• Authors:
    • Meca, A. V.
    • Popescu, N.
  • Source: Annals of the University of Craiova - Agriculture, Montanology, Cadastre Series
  • Volume: 40
  • Issue: 2
  • Year: 2010
  • Summary: Within our country conditions the wheat, rye, barley, oilseed rape and pea-oat fodder are sown in autumn. They may be grown after crops that are harvested during summer or perennial crops or pastures that are included is crop rotation schemes. In the conditions of our country, crops that are harvested during the summer are: pea-oat fodder, pea, early potato, barley and wheat. After harvesting these crops, there must be done, immediately, the summer plowing because the soil is still moist, resulting a good quality plowing. Any delay conducts to diminishing the yields. Usually, the summer plow is made at 18-20 cm depth. Deeper plow are not necessary on most soil types from our country. Twenty cm deeper plow is need only on clayey soil that easily compacts, when the soil is highly infested by weeds, covered by high straw or when in the last year there was made a shallow plow. Summer plow, no matter the depth must be done along with harrow after plow. During the fall, till drilling, the soil has to be harrowed in order to destroy weeds and to maintain soil loosened.
  • Authors:
    • Bengtson, L. E.
    • Fagre, D.
    • Pederson, G.
    • Zeyuan, Q.
    • Prato, T.
    • Williams, J. R.
  • Source: Environmental Management
  • Volume: 45
  • Issue: 3
  • Year: 2010
  • Summary: Potential economic impacts of future climate change on crop enterprise net returns and annual net farm income (NFI) are evaluated for small and large representative farms in Flathead Valley in Northwest Montana. Crop enterprise net returns and NFI in an historical climate period (1960-2005) and future climate period (2006-2050) are compared when agricultural production systems (APSs) are adapted to future climate change. Climate conditions in the future climate period are based on the A1B, B1, and A2 CO(2) emission scenarios from the Intergovernmental Panel on Climate Change Fourth Assessment Report. Steps in the evaluation include: (1) specifying crop enterprises and APSs (i.e., combinations of crop enterprises) in consultation with locals producers; (2) simulating crop yields for two soils, crop prices, crop enterprises costs, and NFIs for APSs; (3) determining the dominant APS in the historical and future climate periods in terms of NFI; and (4) determining whether NFI for the dominant APS in the historical climate period is superior to NFI for the dominant APS in the future climate period. Crop yields are simulated using the Environmental/Policy Integrated Climate (EPIC) model and dominance comparisons for NFI are based on the stochastic efficiency with respect to a function (SERF) criterion. Probability distributions that best fit the EPIC-simulated crop yields are used to simulate 100 values for crop yields for the two soils in the historical and future climate periods. Best-fitting probability distributions for historical inflation-adjusted crop prices and specified triangular probability distributions for crop enterprise costs are used to simulate 100 values for crop prices and crop enterprise costs. Averaged over all crop enterprises, farm sizes, and soil types, simulated net return per ha averaged over all crop enterprises decreased 24% and simulated mean NFI for APSs decreased 57% between the historical and future climate periods. Although adapting APSs to future climate change is advantageous (i.e., NFI with adaptation is superior to NFI without adaptation based on SERF), in six of the nine cases in which adaptation is advantageous, NFI with adaptation in the future climate period is inferior to NFI in the historical climate period. Therefore, adaptation of APSs to future climate change in Flathead Valley is insufficient to offset the adverse impacts on NFI of such change.
  • Authors:
    • Nepomuceno, A. L.
    • Oliveira, G. M. de
    • Neumaier, N.
    • Rakocevic, M.
    • Farias, J. R. B.
  • Source: Pesquisa Agropecuária Brasileira
  • Volume: 45
  • Issue: 7
  • Year: 2010
  • Summary: The objectives of this work were to determine the heliotropic movements of the upper trifoliates for two soybean cultivars, BR 16 and Embrapa 48, during a daily cycle, in three phenological stages and two water regimes, and to estimate the impact of irrigation and daily leaflet movements on agronomic characteristics and grain yield. Heliotropic movements were studied in three phenological stages: V4-V6, V7-V10, and R5 in irrigated and non-irrigated plots. For each stage, the leaflet elevation and azimuth were measured hourly. Under a low (V4-V6 stage) and mid (V7-V10 stage) leaf area index (LAI) the diaheliotropism was slightly more frequent and intensive in non-irrigated than in irrigated plants, only at early morning and late afternoon hours. At R5 stage (high LAI) the paraheliotropism of superior trifoliates was predominant and more intensive in non-irrigated plants. The heliotropic movements are correlated to carbon gain, but not to environment (light intensity or temperature), for measurements at 11 h. 'Embrapa 48' expresses greater paraheliotropism than 'BR 16' at high LAI, while 'BR 16' displays lower heliotropic plasticity under irrigation. In spite of significant heliotropic differences, genotype and water availability treatments did not influence the final grain yield.
  • Authors:
    • Suyker, A. E.
    • Verma, S. B.
  • Source: Agricultural and Forest Meteorology
  • Volume: 150
  • Issue: 4
  • Year: 2010
  • Summary: Continuous measurements of CO 2 and water vapor exchanges made in three cropping systems (irrigated continuous maize, irrigated maize-soybean rotation, and rainfed maize-soybean rotation) in eastern Nebraska, USA during 6 years are discussed. Close coupling between seasonal distributions of gross primary production (GPP) and evapotranspiration (ET) were observed in each growing season. Mean growing season totals of GPP in irrigated maize and soybean were 1738114 and 99669 g C m -2, respectively (standard deviation). Corresponding mean values of growing season ET totals were 54527 and 45423 mm, respectively. Irrigation affected GPP and ET similarly, both growing season totals were about 10% higher than those of corresponding rainfed crops. Maize, under both irrigated and rainfed conditions, fixed 74% more carbon than soybean while using only 12-20% more water. The green leaf area index (LAI) explained substantial portions (91% for maize and 90% for soybean) of the variability in GPP PAR (GPP over a narrow range of incident photosynthetically active radiation) and in ET/ET o (71% for maize and 75% for soybean, ET o is the reference evapotranspiration). Water productivity (WP or water use efficiency) is defined here as the ratio of cumulative GPP or above-ground biomass and ET (photosynthetic water productivity=SigmaGPP/SigmaET and biomass water productivity=above-ground biomass/SigmaET). When normalized by ET o, the photosynthetic water productivity (WP ETo) was 18.41.5 g C m -2 for maize and 12.01.0 g C m -2 for soybean. When normalized by ET o, the biomass water productivity (WP ETo) was 27.52.3 g DM m -2 for maize and 14.13.1 g DM m -2 for soybean. Comparisons of these results, among different years of measurement and management practices (continuous vs rotation cropping, irrigated vs rainfed) in this study and those from other locations, indicated the conservative nature of normalized water productivity, as also pointed out by previous investigators.
  • Authors:
    • van Rensburg, L. D.
  • Source: South African Journal of Plant and Soil
  • Volume: 27
  • Issue: 1
  • Year: 2010
  • Summary: This is the third soil physics review to be published in South African Journal of Plant and Soil. In the previous reviews the focus was broad and covered almost every aspect of the subject, providing a comprehensive list of contributions in soil physics. For the 25th year anniversary celebration of South African Journal of Plant and Soil, I have chosen to narrow the scope and focus on advances in soil physics in relation to irrigation and dryland agriculture. From a bio-physical viewpoint, South African researchers have made a major contribution to the body of scientific knowledge about irrigation and its application, expressed mainly in the form of irrigation or crop models such as PUTU, SWB and BEWAB. Attention was also given to modern ways of irrigation scheduling based on continuous soil water monitoring. Several irrigation scheduling service providers have adapted their businesses accordingly, with the result that South Africa is probably the leading country in Africa with respect to soil water monitoring and associated communication technology. In contrast, the review has shown that at farm and irrigation scheme level, salt management requires urgent attention. This is necessary as a precautionary measure to protect our natural resources. In the second part of the review the contribution of soil physics in relation to tillage practices is explored, and in particular how these have modified the field water balance components in order to enhance yield and rain water productivity. Based on the results of field experiments, new relationships were established, viz, rainfall and maize yield; water storage and yield; runoff and surface coverage by crop residue mulches; tillage depth, texture and yield relationships. Lastly, the review also showed how the water balance on clay and duplex soils in semi-arid zones can be modified through in-field rainwater harvesting to increase their rain water productivity. This technology has enhanced the livelihoods of many communal families who have applied the technique in their homesteads.
  • Authors:
    • Zhang, L. X.
    • Boahen, S.
  • Source: Agriculture and Biology Journal of North America
  • Volume: 1
  • Issue: 4
  • Year: 2010
  • Summary: One of the major problems associated with the early soybean production system (ESPS) in the Midsouth USA is seed shattering of early maturity group (MG) soybean that mature in the midsummer. Information is needed to measure the impact of this problem and to provide proper management strategies. Studies were conducted to investigate the problem of shattering in MG IV soybean, the dominant soybean group in ESPS, in 2006 and 2007. The objectives of this study were to determine the pattern and critical period of seed shattering of MG IV soybeans under various climatic and production conditions in the Mississippi Delta. A total of 56 and 80 MG IV soybean varieties were evaluated in the experiments in 2006 and 2007, respectively. The varieties were all selected from a Mississippi Soybean Variety Trial and the study was carried out at Stoneville, Mississippi. In 2006, only the April planting (April 19) under irrigation was investigated. In 2007, experiments were conducted on both irrigated and non-irrigated fields. On the irrigated tests, both April (April 23) and May (May 15) planting were examined. Results from both years have indicated that most pods of early MG IV soybean varieties can hold seeds relatively well for the first three weeks after maturity (WAM). However, differences were noted starting from the fourth WAM. Non-irrigated soybean shattered faster than irrigated soybean after three weeks. Irrigated soybean held seeds longer than non-irrigated soybean during the fourth week; however, seed shattering became greater after four weeks even in the irrigated study. When comparing early- and late-planted soybean under irrigated conditions, the later maturing pods held seeds better within the same period after maturity (up to 6 weeks or longer). Late-maturing pods tended to held seed better, most likely due to lower temperatures experienced after late September.
  • Authors:
    • Göksoy, A. T.
    • Sincik, M.
    • Candogan, B. N.
    • Yazgan, S.
    • Bükükcangaz, H.
    • Demirtaş, Ç.
  • Source: African Journal of Biotechnology
  • Volume: 9
  • Issue: 41
  • Year: 2010
  • Summary: The aim of the study was to determine the response of soybean [ Glycine max (L.) Merr.] to drought at various stages of development in a sub-humid environment of Turkey. Drought-stress treatments was applied to plants in 2005 and 2006 by withholding irrigation at six critical stages: completely vegetative (fifth trifoliate) (T 2), flowering (T 3), podding (T 4), seed fill (T 5), full bloom+podding (T 6), and podding+seed fill (T 7). Growth and production was compared in each treatment to full irrigated (T 1) and non-irrigated (T 8) controls. Each drought treatment reduced shoot biomass and seed yield compared to well-watered plants, but only non-irrigated plants or plants droughted at vegetative or flowering stages produced fewer seed pods and seeds. Seed protein and oil content was highest among treatments when plants were droughted during the seed filling stage. Yield increased exponentially with crop water use and ranged from 2.1-2.5 tons ha -1 in non-irrigated plants to 3.5-4.0 tons ha -1 in the well-watered controls. However, plants droughted during the vegetative stage of development produced the highest yield per unit of irrigation water applied (that is, irrigation water use efficiency). This research results will be useful for maximizing soybean production and/or seed quality when irrigation water is limited.
  • Authors:
    • Sabău, N. C.
    • Samuel, A.
    • Brejea, R.
    • Domuța, C.
    • Borza, I.
    • Bara, C.
    • Bara, L.
    • Vușcan, A.
    • Ciobanu, G.
    • Gîtea, M.
    • Moza, A.
    • Jurca, A.
    • Șandor, M.
    • Domuța, C.
  • Source: Research Journal of Agricultural Science
  • Volume: 42
  • Issue: 1
  • Year: 2010
  • Summary: The paper is based on the research carried out during 2007-2009 in the long term trial placed in 1990 on the preluvosoil from Agricultural Research and Development Station Oradea. The preluvosoil from the research field is characterized by the presence of the horizons Bt 1 (34-54 cm depth) and Bt 2 (54-78 cm depth); the colloid clay eluviation determined to appear the El horizon with 31.6% colloid clay. On 0-20 cm depth, the soil has a big percentage of macroaggregates (Phi >0.25 mm), 47.5% bulk density is of 1.41 g/cm 3 and total porosity is median one, hydraulic conductivity is of 21.0 mm/h. The values of the pH indicates a low acid soil, humus, total nitrogen, phosphorus and potassium content are low. The source of irrigation water was a drill of 15 m depth. The chemical parameters of the irrigation water were the following: fixed mineral residue 0.5 g/l; SAR index 0.52; CSR index=-1.7%; N. Florea class=II; there are not some problems regarding the use of irrigation use. There are two factors of the experiment: crop rotation (wheat-monocrop, maize-wheat; maize-soybean-wheat) and water regime (unirrigated; irrigated). Optimum water provisionment was assured in the irrigated variant maintaining the soil water reserve between easily available water content on 0-50 cm depth. The biggest protein and gluten content were determined in the wheat grains from maize-soybean-wheat crop rotation both in unirrigated and irrigated variant and the smallest values were registered in the wheat monocrop. In the irrigated variant the smaller values protein, wet and dry gluten were registered but the differences are unsignificant. The research results emphasized the importance of the crop rotation to obtain an wheat yield with good panification index. The research results are part in the project: PN-II-ID-PCE-2008 2; 690/2009 "The study of influences of some technological elements upon the wheat yield quality in the conditions of the North-Western part of Romania".
  • Authors:
    • Guerra, L. C.
    • Persson, T.
    • Garcia y Garcia, A.
    • Hoogenboom, G.
  • Source: Agricultural Water Management
  • Volume: 97
  • Issue: 7
  • Year: 2010
  • Summary: Studies on irrigation scheduling for soybean have demonstrated that avoiding irrigation during the vegetative growth stages could result in yields as high as those obtained if the crop was fully irrigated during the entire growing season. This could ultimately also lead to an improvement of the irrigation water use efficiency. The objective of this study was to determine the effect of different irrigation regimes (IRs) on growth and yield of four soybean genotypes and to determine their irrigation water use efficiency. A field experiment consisting of three IR using a lateral move sprinkler system and four soybean genotypes was conducted at the Bledsoe Research Farm of The University of Georgia, USA. The irrigation treatments consisted of full season irrigated (FSI), start irrigation at flowering (SIF), and rainfed (RFD); the soybean genotypes represented maturity groups (MGs) V, VI, VII, and VIII. A completely randomized block design in a split-plot array with four replicates was used with IR as the main treatment and the soybean MGs as the sub-treatment. Weather variables and soil moisture were recorded with an automatic weather station located nearby, while rainfall and irrigation amounts were recorded with rain gauges located in the experimental field. Samplings for growth analysis of the plant and its components as well as leaf area index (LAI) and canopy height were obtained every 12 days. The irrigation water use efficiency ( IWUE) or ratio of the difference between irrigated and rainfed yield to the amount of irrigation water applied was estimated. The results showed significant differences ( P
  • Authors:
    • Fortuna, A. M.
    • Kennedy, A. C.
    • Stubbs, T. L.
  • Source: Journal of Agricultural and Food Chemistry
  • Volume: 58
  • Issue: 1
  • Year: 2010
  • Summary: Residue from cultivars of spring wheat ( Triticum aestivum L.), winter wheat, and spring barley ( Hordeum vulgare L.) was characterized for fiber and nutrient traits using reference methods and near-infrared spectroscopy (NIRS). Calibration models were developed for neutral detergent fiber (NDF), acid detergent fiber (ADF), acid detergent lignin (ADL), carbon (C), sulfur (S), nitrogen (N), and C:N. When calibrations were tested against validation sets for each crop year, NIRS was an acceptable method for predicting NDF (standard error of prediction (SEP) 0.90) and ADF (SEP0.92) and moderately successful for ADL in 1 year of the study (SEP=0.44; R2=0.81) but less successful for C, S, N, and C:N ( R2 all <0.57). These results indicate that NIRS can predict the NDF and ADF of cereal residue from dryland cropping systems and is a useful tool to estimate residue decomposition potential.