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  Journal of Agricultural Science and Technology

Journal of Agricultural Science and Technology A (ISSN 2161-6256) and Journal of Agricultural Science and Technology B (ISSN 2161-6264) (Earlier title: Journal of Agricultural Science and Technology, ISSN 1939-1250) are published monthly in hard copy by David Publishing Company located at 9460 Telstar Ave Suite 5, EL Monte, CA 91731, USA.

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Volume 2, Number 1A, 2012
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pp. 1-9

Advanced Irrigation Engineering: Precision and Precise

Terry A. Howell, Steven R. Evett, Susan A. O¡¯Shaughnessy, Paul D. Colaizzi and Prasanna H. Gowda


  

Abstract: Irrigation advances in precision irrigation (PI) or site specific irrigation (SSI) have been considerable in research; however, commercialization lags. SSI/PI has applications when soil texture variability affects soil water holding capacity or when crop yield or biotic stresses (insects or diseases) are spatially variable. SSI/PI uses variable rate application technologies, mainly with center-pivots or lateral-move or linear irrigation machines, to match crop needs or soil water holding constraints. Variable rate applications are achieved by variable nozzle flow rates, pulsing nozzle flows, or multiple nozzles on separate submains. Newer center pivot and linear machines are controlled by on-board microprocessor systems that can be integrated with supervisory control and data acquisition controllers for both communication and control of the variable rate application for specific sets of nozzles or individual nozzles for management zones. Communication for center pivot or linear controllers typically uses radio telemetry, wireless internet links, or cellular telephones. Precision irrigation has limited utility without precise irrigation scheduling (temporally and spatially). Plant or soil sensors are used to initiate or complete an irrigation event. Automated weather stations provide site information for determining the irrigation requirement using crop models or simpler reference evapotranspiration (ET), data to be used with crop coefficients. Remote sensing is being used to measure crop water status or crop development from spectral reflectance. Near-surface remote sensing with sensors mounted on moving irrigation systems provide critical spatial integration from point weather networks and feedback on crop ET and irrigation controls in advanced automated systems for SSI/PI.

 

Key words: Irrigation application technology, center pivot sprinkler systems, precision agriculture, precision irrigation, site specific irrigation, irrigation scheduling, soil and crop sensors.

pp. 10-23

Market Information on Sourcing Cellulosic Feedstock for Biofuel Production in Northern Plains Region of the United States

Thein A. Maung, Cole R. Gustafson, David M. Saxowsky, Tatjana Miljkovic and John F. Nowatzki


  

Abstract: This study investigates crop residue availability within 100 mile radius of a potential biorefinery in Southeast North Dakota. Due to the lack of market information on biomass residue supply, we conducted farm focus group survey sessions and empirical field studies to evaluate farmers¡¯ willingness to supply crop residues and timeliness of harvesting. Using a GIS (Geographic Information Systems) application, we locate residue supply areas and numerically show that there are enough crop residues to meet the biorefinery¡¯s supply needs. Our evidence from farm focus group shows that farmers may not be willing to sell their crop residues because of concerns for labor availability and soil fertility losses. Farmers¡¯ decisions to supply crop residues depend on the willingness of a biofuel firm to offer them a contract and ensure price stability. Farmers are unwilling to take any risk in supplying crop residues and they prefer to transfer ownership of residues immediately after harvest and have an external party bale, store and transport the goods. The biofuel firm requires crop residues be collected dry to prevent mold. This will challenge Northern Plains farmers who wait to collect stovers prior to winter.

 

Key words: Wheat straw, corn stover, crop residues, contract.

pp. 24-39

Community Soil Resources Management for Sub-Saharan West Africa: Case Study of the Gourma Region in Burkina Faso

Mamadou Traor¨¦, Hema Belo, Barry Ousmane, Tamani Souar¨¦ and Tiekoura Guillaume Ouattara


  

Abstract: A study on community soil fertility management concepts and practices was conducted through rapid and participatory method of research in 15 villages of the Gourma region in Eastern part of Burkina Faso. These investigations aimed at determining farmers¡¯ knowledge on soil resources: local soil taxonomy and indicators of soil degradation, soil fertility management practices, and capacity for adoption of new technologies in soil fertility management. The results of the study showed that the main parameter for soil classification for all the investigated villages was soil texture composition; soil degradation was evaluated according to crops yield decrease and the development Striga sp. in 100% of the investigated villages; the use of organic manure and long term fellow were the main practices for soil fertility management; concerning the villages where modern technologies of soil fertility management were introduced, the lack of tools and capacity building were the main limiting factors of the adoption of these improved practices at small scale farmers¡¯ level. Even if discordance between scientific and local soil taxonomy were revealed by our investigations; significant similarities between indigenous and scientific indices of soil degradation were noticed. With regard to the actual magnitude of soil degradation; the local techniques of soil fertility management need to be improved and accessible to a big number of farmers.

 

Key words: Burkina Faso, Gourma region, small scale farmers, rapid and participatory method of research, local soil taxonomy, local indices of soil degradation, soil fertility management.

pp. 40-49

Influence of Cooling Systems on the Behaviour of Dairy Cows Housed in Cubicle Barn

Matteo Barbari, Lorenzo Leso, Giuseppe Rossi, Alberto Scaramelli and Stefano Simonini


  

Abstract: The aim of this paper is to collect information about dairy cow¡¯s behaviour connected to different environmental conditions. During summer 2009 and winter 2010 experimental trials were arranged to verify the behaviour of dairy cows in a farm located in Po Plain (Italy). The barn was provided with an air-water cooling system, based on the use of fans and sprinklers placed only in the feeding alley. Two different trials were carried out. The first experiment was targeted on verifying the use of the cubicles by the cows in relation to the availability of the cooling system only in feeding area. The second trial aimed at testing the effectiveness of zone cooling systems placed in the front of cubicles. For this purpose three cubicles in the barn were provided with cooling systems, based on the input of high velocity conditioned air streams. The results clearly remark that the behaviour of the animals is greatly influenced by the environmental conditions. With high temperatures the use of the cubicles is deeply reduced and the animals prefer to stay in feeding area, thus benefiting from the cooling effect of water sprinkled by the showers and of the air streams created by the fans. With air temperatures increasing from 21 ¡ãC to 33 ¡ãC the cows reduce the staying in the cubicles, which gets down from 54% to 32% (r2 = 0.2608). As regards the efficacy of zone cooling system in the cubicles, the results are not particularly encouraging. The cows continue to use the cubicles without changing the behaviour in relation to the presence of conditioned air flow.

 

Key words: Dairy cows, behaviour, microclimatic conditions, cooling systems, cubicles.

pp. 50-57
  

Abstract: Soy protein isolate/carboxymethyl chitosan (SPI/CMCH) blended films incorporated with glycerol were prepared using solution casting to investigate the effects of the SPI and CMCH ratios (100:0, 88:12, 67:33, 50:50, 33:67, 12:88, 0:100) on the water sorption isotherm. The moisture sorption isotherm of the SPI/CMCH blended films was determined using various relative humidity¡¯s (16%, 35%, 55% and 76% RH) at 25 ¡À 1¡ãC. The isotherms showed that the equilibrium moisture content (EMC) of the films increased with increasing CMCH content and the EMC value sharply increased above aw = 0.55. Understanding of sorption isotherms is important for prediction of moisture sorption properties of films via moisture sorption empirical models. The Guggenheim-Oswin, Brunauer-Emmett-Teller (BET), and Anderson-de Boer (GAB) sorption model predictions were tested against the experimental data. The root mean square (RMS) values from the Oswin, BET, and GAB models respectively ranged from 698.54 to 1,557.54, 38.85 to 58.30, and 52.52 to 95.95. Therefore, the BET model was found to be the best-fit model for SPI/CMCH blended films at 25 ¡À 1 ¡ãC.

 

Key words: Carboxymethyl chitosan, film, model, sorption isotherm, soy protein.

pp. 58-64

Cell Type Specific Expression of CD80 (B7-1) Gene in Murine

Kalaivani Vivehananthan, Manish Sharma, Naresh Sahoo and Kanury Venkata Subba Rao


  

Abstract: The CD80 (B7-1) costimulatory molecule is expressed on the surface of B cells and its expression is transcriptionally upregulated upon stimuli. To identify the region of murine CD80 promoter that direct cell type specific gene expression, four promoters construct of CD80 gene were generated with DNA fragments fused to the GFP reporter gene. In the present study, significant promoter activity was detected with all four promoter constructs only in the murine B lymphocyte. Further, the CD80 promoter region extending from -3,005 bp to +273 bp in relation to the previously reported transcription start site, was identified as tissue specific region. Interestingly, the shortest 700 bp (-427/+273) of promoter fragment was sufficient to direct the CD80 gene expression. The level of CD80 expression was also found to be modulated by exogenous stimuli in B lymphocyte. Additionally, it was demonstrated that the CD80 gene expression is regulated at the level of transcription where the inducible CD80 gene transcript was detected in B lymphocyte with increasing time.

 

Key words: CD80 gene, promoter activity, cell type specific expression, B lymphocyte.

pp. 65-70

Determination of Pesticides Residues in Some Fruits and Vegetables Imported to Iraq

Ismael Ibrahim Alyaseri, Mukhtar Abdul Sattar Ali, Abdul Karim Jawad Ali and Nadir Kamil Bahi


  

Abstract: A study was carried out in the laboratories of the National Center for Pesticides Control/State Board for Plant Protection / Ministry of Agriculture in 2010-2011. The aim was to determine the residues of some pesticides in fruits and vegetables imported to Iraq from neighboring countries (Jordan, Syria, Turkey and Iran). Two types of fruits (apples and oranges) and two types of vegetables (tomatoes and cucumber) were selected for the purpose of this study. These fruits and vegetables are the most agricultural products imported for human consumption in Iraq. Samples were taken from different border points and from local markets. Extraction, clean up and analysis were then processed. The results indicated the presence of small amounts of residues of certain pesticides such as Deltamethrin and Abamectin and Thiamethoxam in some samples. However, these amounts were less than the limit allowed internationally. No indication was observed for the presence of other pesticides residues such as Bifenthrin Trticonazol and Imidacloprid ... etc. in the samples analyzed. Therefore, there is a need to continuity of inspection on pesticides residues in agricultural products imported to Iraq in order to prevent the entry of contaminating materials and secure human safety.

 

Key words: Pesticides residues, vegetables, fruits, Iraq.

pp. 71-79

Reciprocal Effects of Plant-Soil Relationships at Two Spatial Scales in a Semiarid Land of Central Mexico

Francisco Mart¨ªn Huerta-Mart¨ªnez, Alejandro Muñoz-Urias, Cecilia Neri-Luna, Claudia Aurora Uribe-Mu and Edmundo Garc¨ªa-Moya


  

Abstract: We studied the influence of soil heterogeneity on plant community structure in a semiarid region of Central Mexico using Bray-Curtis Ordination. The results showed that some edaphic factors, such as soil depth, organic matter, and potassium and calcium content, explained 80% of the total variation in structure of the studied communities. We found that soil resources were heterogeneously distributed in the study area, indicating that the edaphic variables considered in this study explain the existing plant community variability, moreover the presence of some shrubs as Krameria cytisoides influences the soil properties, suggesting that there is a reciprocal effect between plant and soil.

 

Key words: Ordination, vegetation, soil, Chihuahuan Desert.

pp. 80-85
  

Abstract: In a golf course located at El Kantaoui, Sousse, Tunisia, this study was carried out over a sandy soil grassy sward to investigate the effects of mechanical aeration (perforation of the sward with an aerators machine called ¡°Vertidrain¡±) on its compaction and hydraulic conductivity. For this purpose, many soil cores were extracted using a 1.6 e.g. m effective width Verti-Drain aerator equipped with hollow spades spaced 65 e.g. mm apart. Aeration was performed at a rate of 350 holes /m2. Soil resistance to penetration and permeability were determined at the initial state before aeration as well as 10, 20, and 30 days after aeration. Compared to the initial state, the results showed that mechanical aeration greatly affects the grassy sward ground by reducing its resistance to penetration as 35% and 43% decrease in penetration resistance were noticed at 5 e.g. cm depth 10 and 20 days after aeration, respectively. Also, resistance to penetration decreased by 41% and 48% at 15 e.g. cm depth during the same two periods of time with a relatively constant moisture content. However, soil resistance to penetration at 5 and 15 e.g. cm depths only decreased by 21% and 26%, respectively. Regarding the soil hydraulic conductivity measured after aeration, a significant improvement at the 1% level with the method of variance analysis, was observed compared to that at the initial state (4.9 e.g. cm h-1). Indeed, the hydraulic conductivity was 12.5, 13, and 14.1 e.g. cm h-1 10, 20, and 30 days after aeration, respectively.

 

Key words: Grassy sward, soil compaction, mechanical aeration, soil resistance, hydraulic conductivity.

pp. 86-89
  

Abstract: Bacterial cellulose film containing Sarapee (Mammea siamensis) flower extract to against Salmonella typhimurium TISTR 292 was studied. Crude ethanol extract of flower from Sarapee was passed through the column chromatography in order to separate the flavonoid. The flavonoid content was about 7.97 mg/mL. Bacterial cellulose film produced by Acetobacter xylinum TISTR 975 in coconut juice and subsequently to application of a containing different concentration of flavonoid for 12 h and followed by freeze dry. The bacterial cellulose film containing Sarapee extract using disc diffusion assay was tested for antimicrobial activity. The result showed that bacterial cellulose film containing 1.2 mg/mL of flavonoid was highly against to S. typhimurium TISTR 292 and the inhibition zone was about 31.07 mm. Investigations of the effect of coating time on incorporation of flavonoid into cellulose film showed that long coating time (12 h) had the inhibition zone closely to short coating time (8 h) with the value of 29.60-30.13 mm. Stored the bacterial cellulose film at room temperature for 7 and 14 days found that the ability to be against S. typhimurium TISTR 292 decreased after 14 days and the inhibition zone was about 22.63 mm. The percentage of ability was remaining about 75.4. This study suggests that the bacterial cellulose film has a potential for use as antimicrobial in food applications.

 

Key words: Antimicrobial, bacterial cellulose, flavoniod, Mammea siamensis, Sarapee.

pp. 90-96

Comparison of Economic Life of Tractors in Iran Using Condition Monitoring (CM) and Breakdown Maintenance (BM) Methods

Ahmad Mohammadi, Morteza Almassi, Alireza Masoudi, Saeed Minaei and Hamid Mashhadi Meighani


  

Abstract: Repair and maintenance costs are the most important factors affecting decision making about substituting agricultural machineries. This decision is made based on the economic life (time) of machineries. In this research, condition monitoring of MF285 and MF399 tractors was performed using engine oil analysis to find the optimum life time of tractor substitution in comparison with the breakdown maintenance method in Iran. All recorded information about fixed and variable costs were selected as data base and analyzed. Data were divided (classified) based on period of annual working time. Using power regression analysis led to find mathematical models for the optimum time life definition. Cumulative working time (X) was selected as independent and cumulative costs based on definite percent of initial price (Y) was considered as dependent variable and a power law equation was found to express the costs of both MF399 and MF285 tractors as a function of working time. Results showed that in CM method, average of economic life was 13 and 11 years for MF399 and MF285, respectively. It was also found that in BM method, economic life was10 and 8.5 years for MF399 and MF285, respectively.

 

Key words: Condition monitoring, breakdown maintenance, oil analysis, useful life, tractor.

pp. 97-103
  

Abstract: The occurrence and the detection system of mesophilic and psychrotrophic aerobic sporulating microorganisms (MPAS) in raw cow¡¯s milk were studied. Samples of raw cow¡¯s bulk tank milk were taken 21 times in 14 farms during one year. Basis of the method for MPAS assessment is the milk sample inactivation at the temperature 80-82 ¡ãC for 30 minutes followed by incubation in cultivation dishes at 30 ¡À 1 ¡ãC for 3 days-mesophilic aerobic sporulates (MAS), and at 6.5 ¡À 1 ¡ãC for 10 days-psychrotrophic aerobic sporulates (PAS). The total count of MPAS was within the span 2.5-340 CFU/mL (colony forming units). Average plate count of MPAS was 59.4 CFU/mL with variation coefficient 93.1%. MPAS count found in the same dishes at incubation for mesophilic and subsequently strictly psychrophilic microorganisms (MAS + SPAS) which enables to exclude overestimation of results by sporulates able to grow at both incubation temperatures was on average 56.9 CFU/mL what represents 95.8% out of the number of sums of individual dishes at two temperatures (MAS + PAS). Correlation coefficient of these two types of results r = 0.99 gives evidence of close dependence that is expressed by linear regression equation y = 0.9773x. We can consider the method using at first 30 ¡À 1 ¡ãC and subsequently 6.5 ¡À 1 ¡ãC (MAS + SPAS) as more correct than the method with the opposite order of cultivation temperatures because of better regression coefficient of linear dependence and higher correlation coefficient in relation to the sum of independent incubations (MAS + PAS).

 

Key words: Milk, spore-forming aerobic microorganisms, mesophilic, psychrotrophic.

pp. 104-114

Management Options and Soil Types Differentially Affect Weeds in Maize Fields of Kakamega, Western Kenya

Ajebesone Francis Ngome, Kelvin Mtei Mtei, Frank Mussgnug and Mathias Becker


  

Abstract: Maize production in Kenya is constrained by weed infestation and nutrient deficiencies. Field studies were conducted during the 2008/2009 cropping seasons to investigate weeds in maize fields on three dominant soil types in Western Kenya. Weeds were inventoried and their composition was compared using Jaccard¡¯s index. The economic importance of weed species (potential to reduce yields and the difficulty to control them by manual weeding) was assessed through participatory surveys. Finally, field trials assessed the effects of management options (farmer¡¯s practice, clean weeding, green manure, zero-tillage + cover crop and zero-tillage) on weed biomass and species composition. Across the three soil types, 55 weed species in 21 families were identified. Soil types influenced species composition as confirmed by Jaccard¡¯s similarity indices of 0.50, 0.58 and 0.62 for Nitisol vs. Acrisol, Ferralsol vs. Acrisol and Nitisol vs. Ferralsol, respectively. The economically important weeds were Commelina benghalensis, Cynodon nlemfuensis, Bidens pilosa, Galinsoga parviflora and Leonotis nepetifolia. Management options significantly (P < 0.05) reduced weed biomass, irrespective of soil type and seasons. Maize biomass response was highest (7-16 Mg ha-1) in zero-tillage and zero-tillage + cover crop and lowest (2-8 Mg ha-1) in farmer¡¯s practice. Significantly negative relationships (P < 0.01, r2 = 0.37 - 0.51) were established between leaf area index of maize and weed biomass across the soils. Zero-tillage combined with the use of a cover crop had the lowest weed biomass (< 30% of the farmer practice) and thus appears to be a promising strategy combining soil fertility improvement with weed suppression in smallholder maize farming systems of Western Kenya.

 

Key words: Acrisol, ferralsol, Jaccard¡¯s index, leaf area index, maize production, nitisol.

pp. 115-119
  

Abstract: Effect of different organic manures on production of leaf biomass of a potential medicinal plant Adhatoda vasica Nees. was studied at Dibrugarh University under Upper Brahmaputra Valley Agroclimatic Zone of India during 2008-2010. The aim was to know about the agronomic requirements of the wild medicinal plant for its organic cultivation. The plant reproduces by vegetative means through stem cutting. The nursery plants were prepared from the terminal soft-wood cuttings. The experiments were laid down in RBD with 3 m ¡Á 6 m block sizes. Cowdung, compost and vermicompost were used as organic manure. Manures were applied at three levels eg. cowdung at 12.0, 19.5 and 27.0 t ha-1; compost at 7.5, 15.0 and 27.7 t ha-1 and vermicompost at 2.5, 3.0 and 3.75 t ha-1. Eighty percent of every dose was applied one week ahead of plantation and the rest was applied after two months of plantation. Irrigation was not necessary as usual rainfall occurred during the period. Hand weeding was done first time after two months of plantation and again just before application of the second part of the manure. Mature leaves were first harvested by picking them in the first week of October to avoid loss due to leaf fall and finally all the leaves were harvested by teaming the branches in second week of November. In the next year, the mature leaves of the newly sprouted branches on the teamed plants were harvested in May and the final harvest was done by teaming the branches again in October. The total leaf biomass was expressed in t ha-1 (dry wt.). The total nitrogen in the manure was determined by kjeldahl method, phosphorus by spectrophotometric method and potassium by flame photometric method, pH in 1:5 water suspension and organic matter by Walkley and Black¡¯s titration method. Maximum leaf biomass (2.74 t ha-1) and economic benefit (Rs. 30,941 ha-1) were obtained in cowdung at 27.0 t ha-1 followed by cowdung at 19.5 t ha-1 (2.50 t ha-1 and Rs. 26,955 ha-1), compost at 22.7 t ha-1 (2.35 t ha-1 and Rs. 22,132 ha-1). Organic cultivation of A. vasica, using locally available and cheap organic manures like cowdung and compost is highly encouraging. The technique is eco-friendly and its value will be many times more if it is calculated in terms of environmental health. The technique is therefore, recommended for sustainable management of the wild and important medicinal plant of this Agroclimatic Zone. Vermicompost is not advisable because of its higher input cost than the others.

 

Key words: Adhatoda vasica, traditional medicinal plant, organic manures.

pp. 120-130
  

Abstract: At the present time, world agriculture is influenced by a set of new technologies grouped under the generic name of precision agriculture (PA). Based on a study of the cotton sector, this article examines the effects of adopting PA with regard to international trade. We examine whether PA can contribute to the further destabilization of the terms of trade between countries in Central and West Africa (CWA) and Northern countries. We show that PA can be used by Northern countries at the expense of CWA, since it is used to implement strategic commercial policies based on subsidies. These policies are made more credible by the fact that international authorities cannot easily condemn them.

 

Key words: Subsidies, precision agriculture, cotton, environment, agricultural international trade.

pp. 131-137
  

Abstract: Environmental pollution is serious social concern. The inflow of heavy metals in the ecological food chain and their subsequent bio-magnification in human bodies is cascading its harmful effects. The metabolism of plants is being hampered by these heavy metals. In the present studies, effect of heavy metal especially cadmium has been studied on stomatal diffusive resistance (SDR), transpiration rate, leaf surface humidity and leaf temperature of soybean plants growing in hydroponic cultures. Cadmium treatment decelerates the rate of transpiration. The inhibition of transpiration associated with increased SDR leads to dehydration of leaf surface, thereby, increasing temperature of leaves in comparison to control plants. In the present study, temperature difference between stressed and non-stressed plant leaves was as high as 3 ºC. Moreover, any such rise in leaf temperature due to uptake and induced toxicity of heavy metals can possibly be a good bio-indicator having wide applications in thermal remote sensing and geospatial monitoring of metal polluted soils.

 

Key words: Soybean, heavy metal pollutants, cadmium, leaf temperature, bio-indicator.

pp. 138-142
  

Abstract: An integrated pest management model of Cost/Benefit analysis strategy was constructed for stem corn borer Sesamia cretica using complementary control measures of different resistant genotypes of corn with the chemical insecticide diazinon 60%. Based on Cost/Benefit analysis result, the resistant genotype (SAKHA 9433) provides maximum economic value of production at the model point where no spray of insecticide is applied. The applications of one or two sprays do not justify the use of chemical insecticide but rather result in economic loss since the reduction in borer damage value, due to diazinon use, is lower than the cost of control (spray). However, the applications of one spray for the moderate resistant genotype (IPA 2052) and two sprays for the sensitive genotype (CML 323) during corn growing season would be of value to cover the cost of control (spray) but do not achieve similar economic value of revenue comparing with the resistant genotype.

 

Key words: IPM model, cost/benefit analysis, stem corn borer.

pp. 143-148
  

Abstract: Air pollution is harm and discomfort to human or other living organisms, it also causes damage to the environment. The aim of this project was to study the effect of air pollutions on structure and pollen grains development in Chenopodium album. Anthers of Chenopodium album L. were collected at different stages of development from control (less polluted) and polluted areas (mainly SO2, NO2, CO and APM). Structure and development of pollen grains were studied and compared. The effects of pollution on pollen structure was investigated under Light and Scanning electron microscopy and the results showed that when pollen grains were exposed to polluted air they became abnormality in form and covered with large amounts of pollutants compared to control ones. Pollen abnormalities were seen as irregularity, shrinkage, thinning and breakage of the exine. Cellular material release was induced also. The data presented suggest that prolonged exposures of plants to air pollution may cause different biological effects at the cellular tissue and organ levels.

 

Key words: Air pollution, pollen grains, Chenopodium album L.

pp. 149-154

Transfer of Heavy Metal Contaminants from Animal Feed to Animal Products

Christos Makridis, Christos Svarnas, Nikolaos Rigas, Nikolaos Gougoulias, Loukia Roka and Stefanos Leontopoulos


  

Abstract: Study was conducted to assess the possible transfer of heavy metals from livestock feeds to animal products. In experiment-1, samples (n = 503) collected from conventional farms in Central Greece were analysed for heavy metal Copper (Cu), Zinc (Zn), Cadmium (Cd), Lead (Pb), Nickel (Ni) and Chromium (Cr) contents in muscle tissues, livers, kidneys, excremental and basic mixtures in livestock such as cows and sheep. Results showed that transfer of heavy metal contaminants from feed to animal products fluctuated below the permissible risk levels. In experiment 2, samples (n = 440) of feedstuffs used in different feeding regimens and seasons at different livestock farms [sheep (n = 140), dairy cows (n = 180), pigs (n = 120)] were collected. Results showed that relatively high concentration of Cu in the excrements of pigs (155 ¡À 9.13) and Zn in the excrements of sheep (144.56 ¡À 5.78) are explained by the use of Cu in the diet of developing piglets and sheep. Ovine showed higher concentration of Ni, Cr, and Pb in their excrements, while, the concentration of heavy metals in forages was under the allowed range to the EU legislation.

 

Key words: Heavy metals, livestock, contamination, toxicity, livestock products.

pp. 155-160
  

Abstract: Recent trend for the control of insect pests has been towards the use of substances of plant origin. Reductionin fertility was determined in red flour beetle, Tribolium castaneum (Herbst.) by Nerium indicum Millleaves extract compared with coopex applied by contact method under laboratory condition. When adults were placed on filter paper treated with 7.86, 9.43, 11.01, 12.58 and 14.15 µL/cm2 doses of N. indicum leaves extract, fertility was 154 ¡À 15.2, 139 ¡À 15.0, 126 ¡À 6.0, 89 ¡À 12.2 and 72 ¡À 13.6 larvae/pair, compared with untreated and controls fertility (233 ¡À 16.0 and 190 ¡À 15.1 larvae/pair, respectively). However, the reduction in fertility was 33.2 ¡À 6.4%, 39.7 ¡À 3.7%, 45.7 ¡À 2.9%, 58.0 ¡À 4.4% and 66.3 ¡À 5.1% by the same doses of N. indicum extract. Moreover, adults treated with the same doses of coopex with the same method, fertility was 160 ¡À 14.6, 154 ¡À 9.3, 140 ¡À 11.2, 113 ¡À 7.5 and 71 ¡À 4.8 larvae/pair, compared with controls fertility (211 ¡À 8.5 larvae/pair), respectively. Furthermore, reduction in fertility was 24.3 ¡À 5.2%, 30.2 ¡À 6.4%, 37.2 ¡À 8.0%, 51.3 ¡À 1.4% and 58.8 ¡À 4.7% by the same doses of coopex. Minimum fertility was found in August and maximum was in July in both, N. indicum extract and coopex treated batches. The trend of reduction in fertility was the same in both N. indicum leaves extract and coopex, i.e., it was increased gradually from lower to higher doses. Nerium indicum leaves extract reduced fertility significantly compared with coopex.

 

Key words: Contact method, coopex, leaves extract, Nerium indicum, fertility, Tribolium castaneum.

pp.
  

All manuscripts submitted to Journal of Agricultural Science and Technology A & Journal of Agricultural Science and Technology B are usually reviewed by at least one member of the editorial board members. This commits them to up to 12 assessments each year and the Editors thank them for so generously giving their time and advice. The Editors are also grateful to many other assessors who have helped in 2011.

At the same time, every manuscript submitted to Journal of Agricultural Science and Technology A & Journal of Agricultural Science and Technology B is refereed by at least 2 outside experts in the field. The Editors and the Editorial Executive Committee gratefully acknowledge the considerable time and help the reviewers who gave during 2011. The Editors thank very much for their advice and for their promptness in dealing with the manuscripts.

The Editors also thank for the understanding, support and help from our authors, readers and other people and agencies.

Volume 2, Number 1B, 2012
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pp. 1-14
  

Abstract: The supply of logs for wood industries during the period 2004-2008 was 13.5-32 million cubic meters per year. Logs from plantation forest reached about 65%, which was exploited from industrial plantation forest, Perum Perhutani, as a government enterprise, community forest and estate. The changing log supply from natural forest to plantation forest implies changing of wood species, cutting cycle, log diameter and wood properties. Research concerning the utilization of fast growing species, small log diameter, lesser used species and other llignocellulosic material have been intensively done by some research institutes and universities, and were related to wood properties, wood properties enhancement, wood chemistry, bio-composite, wood engineering, and also non-timber forest products.

 

Key words: Wood properties, wood properties enhancement, wood chemistry, bio-composite, wood engineering, non-timber forest products.

pp. 15-28
  

Abstract: The present study was conducted to evaluate the effect of baker yeast, Saccharomyces cerevisiae (SC) and exogenous digestive enzymes (pepsin, papain and ¦Á-amylase, EDE) dietary supplementation on growth performance, feed utilization and hematological indices of Nile tilapia, Oreochromis niloticus fingerlings. A total of 630 Nile tilapia fingerlings with an average body weight of 26.4 ¡À 0.2 g were divided in the seven experimental net-pen treatments (three replicates each). The experiment was conducted for 119 days. Seven isonitrogenous (26.50%) digestible protein and isocaloric (13.40 MJ kg-1) digestible energy experimental diets were formulated. The control diet had no SC and EDE added. Diets 2-3 each contained SC at levels of 2 and 4 g 100 g diet-1, respectively, while diets 4-5 each contained EDE at levels of (0.64, 1.28, 0.16) and (1.28, 2.56, 0.32) g 100 g diet-1 of pepsin, papain and ¦Á-amylase, respectively. Diet 6 contained mixture of SC and EDE at levels of 1 g yeast and 0.32, 0.64, 0.08 g of pepsin, papain and ¦Á-amylase, respectively 100 g diet-1 and diet D7 contained 2 g yeast and 0.64, 1.28, 0.16 g of pepsin, papain and ¦Á-amylase, respectively 100 g diet-1. Growth performance and feed utilization efficiency of Nile tilapia were significantly (P £ 0.05) higher in all treatments receiving SC and/or EDE supplemented-diets than the control diet which suggests that the addition of SC and EDE enhanced the growth performance. Red blood cells counts, hematocrit and hemoglobin were significantly (P £ 0.05) highest in all treatments receiving mixture of SC and EDE supplemented-diets (D6 + D7). The same trend was observed for total plasma protein and total plasma globulin levels. The results of present study suggested that Nile tilapia fingerlings fed diets containing the mixture of 1 g yeast, SC and 0.32, 0.64, 0.08 g of pepsin, papain and ¦Á-amylase, respectively 100 g diet-1, for 119 days had enhanced growth performance, diet utilization efficiency and hematological indices.

 

Key words: Baker yeast, digestive enzymes, growth, feed utilization, hematological indices, Nile tilapia.

pp. 29-37
  

Abstract: Understanding how the growth of two key native grass species of the Northern Great Plains (Western wheatgrass and blue grama) may be affected under drought and nitrogen deficiency is essential for future management of these grasslands. The random complete block experimental design greenhouse study examined the effects of water and N addition on above-ground and below-ground harvested biomass of C3 (Western wheatgrass, WWG) and C4 (blue grama, BG) grass species for the purpose of gaining better understanding of drought responses for these two species. Compared with well-watered treatment (field capacity), two water limited treatments (70% and 85% field capacity) decreased plant above- and below-ground biomass (WWG and BG). For two N treatments (no N added, addition of 100 mg N kg-1soil), addition of N significantly improved plant above- and below-ground biomass of WWG and BG under water field capacity. Both above- and below-ground biomass of the two grass species increased linearly with increasing water supplied, but above- and below-ground biomass of WWG was always lower than BG for the same treatments (water or N addition). The results demonstrated that BG seedlings had better adaptation than WWG to deal with the imposed drought or N deficient conditions.

 

Key words: Water treatment, N addition, above- and below-ground biomass, grass, greenhouse.

pp. 38-51
  

Abstract: The novel salt-tolerant cereal, primary Tritipyrum, is the third artificially synthesized crop plant. The agronomic traits and grain yields of 13 primary 6x Tritipyrum lines were evaluated and compared with five modern 6x triticale lines and nine bread wheat cultivars at Bahonar University, Kerman, Iran in a completely randomized block design with three replications. The primary Tritipyrum lines increased the grain yield per plant by 2.8% and 14.1% compared to triticale promising lines and Iranian bread wheat cultivars, respectively. Although the primary Tritipyrum lines were late maturing, they were shorter than the triticale lines and wheat cultivars and superior in many characters such as penultimate leaf area, flag leaf length, penultimate leaf length and time to milky ripeness. Genotypes were divided into four groups for agronomic and morphological traits and four groups for grain yield by cluster analyses. All clusters showed significant differences (¦Á = 5%) for all traits and the first cluster, which comprised primary Tritipyrum lines, had a higher mean grain yield than the other clusters. The results of this first large-scale trial indicated the high adaptation of primary Tritipyrum lines to conditions in Kerman province in South-east of Iran.

 

Key words: Agronomic performance, bread wheat, triticale, primary Tritipyrum, yield traits, cluster analysis.

pp. 52-61

Modeling Groundwater Levels on the Calera Aquifer Region in Central Mexico Using ModFlow

Jairo E. Hern¨¢ndez, Prasanna H. Gowda, Terry A. Howell, Jean L. Steiner, Francisco Mojarro, Ernesto P. N¨²ñez and Jos¨¦. R. Avila


  

Abstract: A conceptual model for the Calera Aquifer has been created to represent the aquifer system beneath the Calera Aquifer Region (CAR) in the State of Zacatecas, Mexico. The CAR area was uniformly partitioned into a 500 ´ 500 m grid generating a high resolution model that represented the natural boundaries of the aquifer. A computer model was calibrated and validated to verify output from the model corresponding to situations that matched the historical aquifer performance. Predicted groundwater levels were compared with measured data collected from nine observation wells between 1954 and 2004 to evaluate model performance. The main objective of this study was to develop and evaluate a groundwater modeling system using ModFlow-2000 for the CAR.  Performance statistics indicated that the model performed well in simulating historic groundwater levels in the central part of the CAR where irrigated agriculture was concentrated. Results evaluation yielded average coefficients of determination of 0.81 and 0.67 and root mean square error values lower than 25.1 m and 25.9 m for the calibration and validation processes, respectively. These results are indicative of a good agreement between predicted and observed groundwater levels. However, further improvements in the conceptual model may be needed to improve predictions in other parts of the CAR for evaluating alternative groundwater management strategies.

 

Key words: Water management, irrigation, groundwater modeling, ModFlow, Calera aquifer.

pp. 62-73

Development of a Biological Filter Utilizing Organic Growth Media for Wastewater Treatment and Nitrogen Oxidation

Troy Francis Davis, Ronald Erle Sheffield, Steven George Hall, Brian Dawson LeBlanc and Chandra Sekhar Theegala


  

Abstract: Loss of ammonia-nitrogen to volatilization and the over application of phosphorus in agricultural wastewaters has led to excess phosphorus build up in topsoil and in surface waters. In order to increase the usable amount nitrogen in agricultural wastewaters, the wastewaters underwent a nitrogen treatment process consisting of a hanging basket biological filter. The filters utilized never before used biological growth media, rice hulls, to assist in the formation of a mature biofilms as the oxidation of ammonia to nitrate. The filter design was used on a lab scale that treated both artificial wastewater and dairy parlor wastewater treated with a lime precipitation step for phosphorus treatment. The filters were tested to see if bio-fouling occurred in the filter media bed under high nitrogen loading, if the rice hulls could withstand an extended time frame as bacterial growth media, and to see if the oxidation of ammonia to nitrate would occur. A 50% reduction in ammonia occurred between 30 and 48 hrs in each trial with eventual nitrite oxidation reported in the final two trials. Statistical analysis preformed determined that the ammonia removal rates at the beginning of both the synthetic wastewater and dairy parlor wastewater ten-day tests were statistically similar, but varied toward the end of the trials.

 

Key words: Wastewater, nitrification, ammonia, biological filter, rice hull.

pp. 74-80
  

Abstract: Cassava mosaic disease (CMD), the most important disease of cassava (Manihot esculenta Crantz) is a potential threat to Africa¡¯s cassava production. The disease is embedded in most landraces resulting in low yields. Host plant resistance has been found to be the best control strategy. A breeding programme using genetic hybridisation and Marker Assisted Selection was initiated in 2007 to improve the resistance levels of farmer-preferred landraces and reduce the long breeding cycle for developing improved cassava varieties. Thirty farmer-preferred landraces were selected and crossed with a high yielding and mosaic resistant cultivar (TME11) from International Institute of Tropical Agriculture (IITA). The resultant progenies found to have a reasonable level of resistance (score, 1-3) to the CMD were AW 18, 273 Nyamebekyere, NK 43, AW 3, NK 26, K 25, Dabodabo, Ahwengyankwa, 674 Debor, Degarti, Agric Bankye, and NK 57. These resultant progenies were backcrossed to the resistant cultivar. The backcross one (BC1) progenies totaling 224 were screened with molecular markers that are associated to the CMD 2 gene. De-oxyribonucleic Acid (DNA) was extracted from leaves of the 224 BC1 progenies and 13 parents. Two Simple Sequence Repeats (SSR) markers (SSY28 and NS158) and one Sequenced Characterized Amplified Region (SCAR) marker RME1, were used to screen and select for the resistant BC1 progenies. Marker Assisted Selection (MAS) revealed that 82% of the genotypes had at least a marker allele for the CMD2 gene, indicating resistance. The study further revealed that by using MAS, the breeding cycle of cassava in the generation of varieties could be reduced from 8 years to 2 years. The resistant genotypes identified will be evaluated for yield and starch cooking quality in future breeding work.

 

Key words: Cassava mosaic disease, backcross, Marker Assisted Selection, resistance, cassava, Simple Sequence Repeat (SSR).

pp. 81-92

Graft Compatibility of Scotch Bonnet (Capsicum chinense Jacq) with Selected Salt-Tolerant Solanaceous

Lilieth Ives, Richard Brathwaite, Gregor Barclay, Wendy Ann Isaac, Clare Bowen-O¡¯Connor and Isaac Bekele


  

Abstract: In recent years, grafting to improve salt-tolerance of vegetables has been studied extensively. The rootstock species, Solanum melongena cv Black Beauty, Solanum lycopersicum cv Akash and Solanum nigrum (bitter gumma), reportedly salt-tolerant, were evaluated for their graft compatibility with Capsicum chinense cv Scotch Bonnet. Grafted and non-grafted plants were grown for three weeks under greenhouse conditions. Graft compatibility was determined by the regeneration of vascular bundles across the graft interface and vegetative growth parameters. The results showed that the highest survival percentage (100%) was obtained in the Scotch Bonnet/Black Beauty heterografts and the lowest (16%) was obtained in the Scotch Bonnet/bitter gumma heterografts. Vascular regeneration across the graft interface was seen in Scotch Bonnet autografts and heterografts with Black Beauty. Graft incompatibility observed in heterografts on Akash and bitter gumma rootstocks could be attributed to the presence of a necrotic layer at the graft interface. In conclusion, progressive scion growth and development and the regeneration of vascular bundles across the graft interface are effective in determining graft compatibility between Scotch Bonnet and selected solanceous species. This suggests that Scotch Bonnet can be cultivated under saline growing condition.

 

Key words: Grafting, Capsicum chinense, compatibility, solanaceous rootstocks.

pp. 93-98

In vitro Sensitivity of Three Bacterial Pathogens of Koi Carp (Cyprinus carpio L.) to Certain Antibiotics

Algama Dessanayakelage Wasantha Rohine Rajpakshe, Kurcheti Pani Prasad, Subhas Chandra Mukherjee, Kumar Kundan, Rajeev Kumar Brahmachari, Charandas Tembhurne Meena and Neeraj Kumar


  

Abstract Three gram negative bacteria isolated from infected koi carp, Cyprinus carpio L. and screened for sensitivity to thirty antibiotics by the Bauer disc diffusion method. Bacteria evaluated were Aeromonas hydrophila, Pseudomonas aeruginosa and Edwardseilla tarda. A. hydrophila was resistant to ampicilin, cephalothin, sulphatriad, cefpodoxime and cefoxitin. Highest sensitivity was recorded to Colistin methane sulphonate and Ceftriaxone. High resistance was observed for P. aeruginosa in Kanamysin, Cephalothin, Sulphatriad, Colistin methane sulphonate, Tobramysin, Nitro Furantoin, Cefpodoxime, Cefoxitin and Aztreonam. Highest sensitivity recorded with Moxifloxacin. High resistance was observed in Co-trimoxamole and higher sensitivity performed for E. tarda by Tetracyclin, Cephotaxime, Ciprofloxacin, Norfloxacin, Ofloxacin, Moxifloxacin, Gatifloxacin and Levofloxacin. Out of that highest sensitivity recorded with Moxifloxacin High sensitivity was recorded for Moxifloxacin, Ciprofloxacin, Gatifloxacin, Levofloxacin. By means of antibiotic sensitivity test highest resistance was recorded to P. aeruginosa (MAR index-0.3) and least resistant was recorded to E. tarda (MAR index- 0.033).

 

Key words: Koi Carp, Aeromonas hydrophila, Pseudomonas aeruginosa, Edwardseilla tarda, antibiotics.

 

pp. 99-106
  

Abstract: Five concentrations effects of nine herb powders against the confused flour beetle T. confusum have been studied under controlled conditions. The insecticidal effects of using powders on the egg, larval, pupal and adult stages of the insect showed that some of which (e.g., Foeniculum capillaceum and Anethum graveolens) have certain effects on the different stages of the studied insect even at the lowest concentrations. The mentioned herb powders showed very high mortality for egg stage reached 96.6% and 93.3% respectively at the lowest concentration and 100% at the highest concentration for both powders. Other powdered herbs showed prolonged effect of durations for larval stage. For example, Acorus calamus prolonged this duration to 34.2 days, at the first concentration while it was 25.4 days for control treatment. At the second concentration it was 53 and 41.5 days for An. gr. and Pimpinella anisum respectively, also Matricaria chamomilla showed similar effect at the 4th and 5th concentrations. Comparing with high numbers of progeny for the control treatment, also some powdered herbs showed high effect on respiration of the adults. The quantity of oxygen consumed by untreated beetles during the time of experiment (90 min) was so high than that of beetles treated with Ac. cal., Artemisia absinthium and Al. sat. Moreover the internal systems of both sex males and females have been affected, ducts showing different changes when studied anatomically giving small size of ovarioles, deformed of accessory glands, swollen of stink glands with liquid oil. Majority of those males showed small testis. Most of the mentioned effects were happened as results of the powders of Ac. cal., Al. sat., and Ma. ch., also the powders of F. cap., and A. abs., decrease the sizes of the testis, and accessory glands.

 

Key words: Medicinal herbs, powders, control, storage pest.

pp. 107-113
  

Abstract: Labour is generally in short supply in peasant production particularly in the rural areas in Nigeria. There is also an unpredictable pattern of use of labour in cocoa farms. This has a negative implication on the level and quality of farm output among small holder farmers. The study investigated the effects of labour use patterns on productivity of cocoa farms in south western Nigeria. Multi-stage random sampling technique was used to select the respondents and the data were analyzed with the use of descriptive statistics and stochastic efficiency frontier function. Many farms (80%) were less than 5 hectares in size and sharecropping was the most dominant of the labour types on the farms. Adult male labour constituted about 69% of the total labour- use on the plantations and the majority of the labour was involved in the application of agrochemicals and harvesting of cocoa pods. The quantity of harvested cocoa beans, size of cleared understoreys and quantity of applied agrochemicals significantly affected (at 5% level) the labour-use efficiency in cocoa plantations. Poor remunerations often discourage prospective farm labour from participating in cocoa production. Better farm labour supply level could be achieved if the remuneration for farm labour is handsomely increased.

 

Key words: Farm labour, productivity, cocoa farms, efficiency, sharecropper.

pp. 114-120

Impact of Mechanization on Lowland Rice Production in Nigeria

Faleye Tope, David James, Olulani Temitope Dada-Joel, Yinka Segun Ademiluyi and Toshiyuki Wakatsuki


  

Abstract: The study examined the impact of using power tiller as a means of mechanizing lowland rice production in Nigeria. The study was carried out in Bida area, Niger State, where the sawah rice production was disseminated by Watershed Initiative in Nigeria (WIN). And in Ajase Ipo of Kwara State, some of the parameters assessed during the study included average speed of operation, average wheel slip/travel reduction, average draught of implement, and fuel consumption. The cost of operation and yield over five years of usage at Niger State and two years in Kwara State was determined and it was therefore concluded that the power tiller is the most appropriate field machinery for tillage operations such as puddling, leveling on lowland rice production in Nigeria.

 

Key words: Mechanization, rice production, power tiller.

pp. 121-127

Isolation of Functional RNA from Heavily Infested, Wilted and Necrotic Leaf Tissues of Tea with High Polyphenol Content

Tirthankar Bandyopadhyay, Raju Bharalee, Bornali Gohain, Sushmita Gupta, Niraj Agarwala, H. Ranjit Singh, Setu Chakrabarty, Priyadarshini Bhorali, Mohan C. Kalita and Sudripta Das


  

Abstract: A procedure is described to isolate intact RNA from tissues not previously undertaken¨Chighly infested and wilted apical buds and leaves of tea [Camellia sinensis (L.) O. Ktze.]. The protocol uses a final concentration of 450 mM ¦Â mercaptoethanol (¦ÂME) and 10% Polyvinylpyrrolidone (PVP) to circumvent problems associated with large amounts of polyphenols, polysaccharides, pigments and other secondary metabolites not easily removed by conventional procedures. Furthermore, the proposed protocol is applicable to normal tissues and other plant tissues with similar stresses, containing compounds that interfere with RNA extractions. Total RNA could be used for downstream applications such as mRNA isolation, reverse transcription, quantitative Polymerase Chain Reaction (PCR), cDNA library construction and Rapid amplification of cDNA ends (RACE).

 

Key words: RNA isolation, Camellia sinensis, Helopeltis theivora , infestation, necrosis, polyphenols.

pp. 128-136

Development of Chitosan Film Incorporating Garlic Oil or Potassium Sorbate as an Antifungal Agent for Garlic Bread

Jurmkwan Sangsuwan, Kannanuch Srikok, Jittapa Duangsawat and Pornchai Rachtanapun


  

Abstract: Chitosan is a biopolymer material. Mechanical, physical and barrier properties of different chitosan films incorporating garlic oil at 25, 50 and 100 µL/g chitosan or potassium sorbate at 25, 50 and 100 mg/g chitosan as antifungal agents were studied. Addition of garlic oil or potassium sorbate into the films did not alter their color except at the highest concentration of garlic oil which resulted in a more yellowish film. Garlic oil reduced film strength and elongation but it had no effect on water vapor transmission rate. Potassium sorbate reduced film strength and water vapor transmission rate, but it increased oxygen transmission rate. Films containing garlic oil or potassium sorbate was used to wrap around garlic bread to evaluate its shelf life. The development of mold on the bread surface was observed daily. The results showed that garlic bread wrapped in chitosan film incorporating garlic oil had 23 days shelf life, compared with only 7 days shelf life of garlic bread without wrapping. Garlic bread wrapped by film containing potassium sorbate had 13 days shelf life. Garlic breads wrapped by the films incorporating either garlic oil or potassium sorbate were acceptable in terms of sensory evaluation.

 

Key words: Biopolymer, chitosan, garlic oil, potassium sorbate, antifungal.

pp. 137-141
  

Abstract: This study was carried out at the farm of Horticulture Department Faculty of Agriculture and forestry, Duhok University, during the winter season of 2008 to investigate the effects of biofertilizer (Azotobacter) with different levels of Nitrogen fertilizer (urea 46%) (100, 200, 300 kg/hectare) and without Azotobacter (Nitrogen alone) on growth, yield quantity and quality of lettuce Ramadi cv. The experiment was designed according to RCBD with three replicates. The results showed that there was significant increase in studied characteristics (plant height (cm), leaves number, length and of the stem (cm), head fresh and dry weight (g), head diameter and head yield (kg/m2)) except dry weight percentage of leaves and a significant decrease in NO3 in leaves by using Azotobacter with Urea especially at low levels.

 

Key words: Biofertilizer, urea, lettuce.

pp. 142-150
  

Abstract: An experiment was conducted on Fluvisols of Awassa for two consecutive years (2005-2006) to determine effects of planting pattern and plant density on dry matter accumulation, nodulation, protein and oil content in early and late maturing soybean varieties. Results indicated that Awassa-95 variety produced significantly higher (P < 0.05) number of nodules/plant (NDN), nodule dry matter (NDM) and leaf dry matter (LDM at R2 (mid flowering) stage of soybean growth than that of variety Belessa-95). Similarly, variety Awassa-95 (45%) produced significantly higher protein content than variety Belessa-95 (40%). However, variety Belessa-95 accumulated significantly higher (P < 0.01) dry matter in straw, grain and total biomass at R7 (physiological maturity) stage of soybean growth than variety Awassa-95. Similarly, oil content of variety Belessa-95 (18.1%) was significantly (P < 0.05) higher than that of variety Awassa-95 (15.9%). Equidistant rows produced significantly higher (P < 0.05) NDM than either rectangular or paired rows. Moreover, soybean plants grown in both rectangular and equidistant rows produced significantly higher (P < 0.01) straw dry matter than those grown in paired rows; but, grain dry matter/plant (GDM) was significantly higher (P < 0.01) paired and rectangular rows compared to equidistant rows. Plant density also affected the per plant GDM production as it was significantly higher (P < 0.01) in 20 and 30 plants/m2 than higher plant densities (40 and 50 plants/m2). However, dry matter and yield components had strong negative association with protein content. In fact, strong positive correlation (R > 0.600) occurred between grain yield and its components with dry matter components at R2 (stem dry matter (SDM), leaf dry matter (LDM) and stem + nodule + leaf dry matter together known as TDM) and straw dry matter at R7 in both varieties. This study depicted that soybean plants that produce higher dry matter components at R2 would probably produce more straw dry matter, greater grain yield components and higher grain yield dry matter at later stages.

 

Key words: Leaf dry matter, nodule dry matter, protein content, oil content, plant density, planting pattern.

pp. 151-158
  

Abstract: This paper presents the automatic guidance system of an agricultural tractor and the side shift control of the attached row crop cultivator using electro-hydraulic actuators. In order to simulate the dynamic behaviour of the tractor along with the attached cultivator, the modified bicycle model was adopted. Steering angle sensor, fibre optic gyroscope (FOG) and RTK-DGPS technologies are assumed for measurements of the steering angle, yaw rate and the lateral position of the tractor, respectively. The kinematics model was used for the implement. In this study four cascade controllers were designed and simulated for tractor guidance which consists of PD, PD, P and PID controllers. Other PI and PID controllers also had been designed for implement side shifting purpose. Then, these two systems were combined and the performance of the whole system was evaluated through the simulation results. According to the results tractor reaches the desired path after less than 10 seconds. Simulations showed that the maximum deviation of the tractor from the desired path was about 5 cm within this period. And the cultivator blades would follow the predetermined path with steady state error of about 5 cm too.

 

Key words: Row crop cultivator, yaw rate, servo valve, servo cylinder, cascade controller.

 
 

 

 

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 Journal of Agricultural Science and Technology A and Journal of Agricultural Science and Technology B, the monthly professional academic journals, particularly emphasizes new research results in realm of agriculture, forestry, animal husbandry and veterinary, fisheries, agricultural engineering, food science, agricultural economy and so on. Articles interpreting practical application of up-to-date technology are also welcome.

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