• 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:
    • Constantin, N.
    • Zaharia, G. V.
    • Cociu, A. I.
  • Source: Romanian Agricultural Research
  • Issue: 27
  • Year: 2010
  • Summary: The increase of water use efficiency is very important, especially in water-limited conditions. The research project, carried out on cambic chernozem soil at Fundulea, in 2008 and 2009, had as the main objective the evaluation of contribution of the deep sub-soiling, done before the implementation of this experiment, and of certain tillage systems on over-winter soil water storage, water use efficiency (WUE) and water use as well as on the yield of winter wheat ( Triticum aestivum L.), maize ( Zea mays L.) and soybean [ Glycine max. (L) Merr.], in rotation. The following tillage systems were studied: (1) traditional, with moldboard plough (TS); (2) cizel plough tillage (CS); (3) disc/sweep tillage (DS); (4) strip till, only for row crops (ST); and no till (NT). The over-winter soil water storage estimation was based on calculation of the coefficient of rainfall accumulation during winter (CA), and of capacity of soil water conservation (CC). In the case of maize after wheat, CA was 0.6 on plots with deep sub-soiling, 0.6 on plots without deep sub-soiling, 0.6 with TS, 0.6 with CS, 0.7 with DS, 0.7 with ST, and 0.7 with NT. CC was 85% on plots with deep sub-soiling, 85% on plots without deep subsoiling, 82% with TS, 0.84% with CS, 86% with DS, 86% with ST, and 86% with NT. For soybean after maize, CA was 0.5 on plots with deep sub-soiling, 0.6 on plots without deep sub-soiling, 0.5 with TS, 0.5 with CS, 0.5 with DS, 0.6 with ST, and 0.6 with NT. CC was 77% on plots with deep sub-soiling, 79% on plots without deep sub-soiling, 72% with TS, 78% with CS, 78% with DS, 78% with ST, and 79% with NT. Water use and water use efficiency showed non significant differences for all crops under this study on both plots with deep sub-soiling and without deep sub-soiling, suggesting that the yield differences were not significantly determined by water supply. The water use average for wheat was: 380 mm with TS, 377 mm with CS, 395 mm with DS, and 382 mm with NT. For maize, water use was 339 mm with TS, 345 mm with CS, 343 mm with DS, 341 mm with ST and 343 mm with NT. For soybean, water use was 320 mm with TS, 315 mm with CS, 317 mm with DS, 314 mm with ST and 319 mm with NT. Water use efficiency from precipitations was given for wheat, maize and soyabean. Yield increases due to deep sub-soiling were: 0.1% for wheat 1.5% for maize, and 7.3% for soybean. The average yields recorded were: For wheat 4948 kg ha -1 with TS. 4536 kg ha -1 with CS, 4814 kg ha -1 with DS, 5048 kg ha -1 with NT. For maize 8743 kg ha -1 with TS, 8954 kg ha -1 with CS, 8792 kg ha -1 with DS, 7940 kg ha -1 with ST and 9052 kg ha -1 with NT. For soybean 2098 kg ha -1 with TS, 1812 kg ha -1 with CS, 1846 kg ha -1 with DS, 1798 kg ha -1 with ST and 1941 kg ha -1 with NT. The highest yields were obtained with NT for wheat and maize. WUE was strongly correlated with yield, and had the highest values far wheat and maize with NT. In the case of soybean, we consider that a significant yield increase can be obtained with an efficient weed control and soil protection with adequate amounts of residues from the previous crop.
  • Authors:
    • Dourado Neto, D.
    • Righi, C. A.
    • Costa, L. C.
    • Bernardes, M. S.
    • Confalone, A. E.
    • Martin, T. N.
    • Manfron, P. A.
    • Pereira, C. R.
  • Source: Ciência Rural
  • Volume: 40
  • Issue: 5
  • Year: 2010
  • Summary: Predicting crop growth and yield with precision are one of the main concerns of the agricultural science. For these purpose mechanistic models of crop growth have been developed and tested worldwide. The feasibility of an expolinear model for crop growth was evaluated on predicting growth modification on soybean ( Glycine max L. Merrill) of determined and undetermined growth cultivars, submitted to water restrictions imposed on different phenological stages. An experiment was carried out in Azul/Argentina and in Vicosa/Brazil during the growing seasons (1997/1998, 1998/1999 and 2002/2003). The expolinear model was adjusted to the dry-matter data obtained from each treatment. The model showed sensibility of R m (maximum relative growth rate of the culture - g g -1 day -1) to variation in air temperature; of C m (maximum growth rate of the culture - g m -2 day -1) to solar radiation and of T b (lost time-day) to water stress. C m values were higher without water restriction presenting, in both countries, a direct correlation with solar radiation. Without water restrictions, R m values were lower when the average air temperature during the cycle was lower. It was observed that under water stress the culture had a bias to present higher R m values. T b was lower in the irrigated treatments than in those with water deficits. The analysis of the outputs clearly shows the feasibility of the expolinear model to explain the differential growth rates of soybean as a consequence of climatic conditions.
  • Authors:
    • Robertson, G. P.
    • Thelen, K. D.
    • Corbin, A. T.
    • Leep, R. H.
  • Source: Agronomy Journal
  • Volume: 102
  • Issue: 6
  • Year: 2010
  • Summary: Agronomic management during the 3-yr transition period to organic certification influences soil quality and the weed seedbank. We studied two cropping systems during the transition period and the first certified organic season. A 4-yr rotation of corn, soybean, wheat/alfalfa, corn (C-S-W/A-C) [Zea mays L., Glycine max (L.) Merr., Triticum aestivum L., Medicago sativa L.], produced under a more complex management that included manure and cover crop residue, was compared to a perennial based corn, alfalfa, alfalfa, corn (C-A-A-C) rotation. We compared soil aggregate size distribution and bulk density after Year 1 and on completion of the transition period. Weed seedbank populations were quantified through two seasons in the greenhouse. Weed surface density and aboveground weed biomass were quantified in the field. Over the course of the study, the percentage of large soil macroaggregates (> 2000 mu m size class) had 2.7 and 3.4-fold increase for the C-A-A-C and C-S-W/A-C treatments, respectively. The C-S-W/A-C system generated a 4.5-fold increase in aggregates of this class when wheat that was interseeded with alfalfa was harvested as forage. Bulk density decreased 14 and 6% for the C-S-W/A-C and the C-A-A-C systems, respectively. There was a 60 to nearly 300% increase in total weed seeds germinated in the greenhouse for the C-S-W/A-C system. This same system had a 60 to more than 500% decreased weed seedbank density in the field. We conclude from this study that either strategy can improve soil quality while the weed seedbank was better managed in the more complicated C-S-W/A-C system.
  • Authors:
    • Rosa Becker, A.
    • Camilo Bedano, J.
    • Dominguez, A.
  • Source: Soil & Tillage Research
  • Volume: 110
  • Issue: 1
  • Year: 2010
  • Summary: No-till (NT) has been recognized as a management system of low environmental impact when applied in combination with crop residue mulch and rotations involving cover crops. It has been suggested, however, that, if these conditions are not met, NT may result in physical, chemical and biological soil degradation. This study evaluates the effect of NT on the litter decomposition process and on soil macrofauna communities and how changes in soil physical, chemical, and physicochemical properties affect litter decomposition and soil macrofauna. We hypothesised (1) that macrofaunal abundance, richness and diversity would be lower in NT soils than in natural grasslands; (2) that this would be a consequence of unfavourable physical and chemical soil conditions and high inputs of agrochemicals; and (3) that these changes in macrofauna would influence soil functioning, reducing litter decomposition rate. The study was conducted during winter and spring 2007 on Typic Haplustolls from southern Cordoba, Argentina (32 degrees 41' and 32 degrees 50'S; 63 degrees 58' and 63 degrees 44'W). Macrofauna was sampled twice in NT and in natural grasslands (NA) - as a reference situation - by extracting five soil monoliths of 25 cm x 25 cm x 30 cm at each plot. Soil properties were measured using standard methods. The decomposition rate was determined by the litterbag method, using a 2 mm and a 10 mm size meshes to evaluate litter decomposition mediated by macrofauna. NT greatly reduced richness (from 33 species in NA to 12 species in NT) and abundance (from 1870 ind/m(2) in NA to 475 ind/m(2) in NT) of macroinvertebrates, confirming our first hypothesis. Changes in macrofauna community under NT were mainly explained by high compaction and low organic matter content, confirming our second hypothesis. The reduction in earthworm abundance may also be explained by the influence of the intense use of toxic agrochemicals. No-till increased surface horizon bulk density (from 1.22 to 1.33 g/cm(3)) and decreased organic matter content (from 3.51% to 2.58%) and pH (from 6.74 to 6.01) compared with NA. The litter decomposition rate was lower in NT, confirming our third hypothesis, and it was correlated with low earthworms abundance and activity. We conclude that in our study area the capacity of soils under NT to maintain ecosystem functions would be at risk. (C) 2010 Elsevier B.V. All rights reserved.
  • Authors:
    • Vuscan, A.
    • Brejea, R.
    • Bara, L.
    • Bara, C.
    • Samuel, A.
    • Borza, I.
    • Sandor, M.
    • Domuta, C.
    • Domuta, C.
  • Source: Research Journal of Agricultural Science
  • Volume: 42
  • Issue: 1
  • Year: 2010
  • Summary: This paper based on the research carried out during 2006-2008 in Agricultural Research and Development Station Oradea on a preluvosoil. All the soil profile are low acid (6.11-6.8), humus content (1.44-1.75%) is small and total nitrogen is low median (0.127-0.157). After 30 years of good soil management, good practices the soil phosphorus content became very good (from 22.0 ppm to 150.8 ppm) on ploughing depth, potassium content (124.5 ppm) is median. The source of irrigation water was a drill of 15 m depth. Irrigation water quality was very good: pH=7.2; Na +=12.9; mineral residue=0.5 g/l; CSR=-1.7; SAR=0.52. Ten to ten days determination of the soil moisture on 0-75 cm depth emphasized the presence of the pedological drought every year: 39 days in 2006; 104 days in 2007 and 81 days in 2008; soil moisture decreased below wilting point every year too: 5 days in 2006 and 2008 and 6 days in 2007. Irrigation use - 1100 m 3/ha in 2006, 2900 m 3/ha in 2007, 3350 m 3/ha in 2008 - for maintaining the soil water reserve between easily available water content and field capacity determined the improve of the soybean microclimate. The values of de Mrtonne aridity index (IdM) for optimum irrigated soybean characterized the microclimate like "wet" in 2006 (IdM=45.2) and 2007 (IdM=44.2) and like "wet I" in 2008 (IdM=53.4). Irrigation suspending in the different months of the soybean irrigation season determined a smaller values of IdM and a worse microclimate, too. The biggest soybean yield were obtained in the irrigated variant without irrigation suspending in the soybean irrigation season: 3510 kg/ha in 2006, 3170 kg/ha in 2007 and 4050 kg/ha in 2008. In comparison with this variant the yield losses from unirrigated variant were of 25.4% in 2006; of 81.7% in 2007 and of 66.6.% in 2008; the yield losses are very significant statistically. Very significant statistically are the yield losses from the variants with irrigation suspending in the months of soybean irrigation season, too. The inverse link between pedological drought and yield and the direct link between de Martonne and yield sustain, too the need of the irrigation for pedological drought control and for microclimate improve in soybean from Crisurilor Plain.
  • 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:
    • Egli, D. B.
  • Source: Crop Science
  • Volume: 50
  • Issue: 5
  • Year: 2010
  • Summary: The number of pods and seeds produced by soybean [ Glycine max (L.) Merr.] is related to canopy photosynthesis during flowering. The effect of low photosynthesis during only a portion of flowering (growth stage R1 to R5), however, is not well defined. Two field experiments were conducted at Lexington, KY (38degreesN), with seeds sown in mid-May in 0.76-m rows (20 seeds m -1 of row) and all plots irrigated as needed. In 2005/2006, plants (cultivars Pennyrile and Ripley) were shaded (60% in 2005 and 80% in 2006) for 4- to 9-d periods just before or just after peak pod production. These treatments had almost no effect on seed number (significant reduction in only one of eight comparisons). In a second experiment (cv. Pennyrile, 2007/2008), shade cloth (60%) was placed over plants at growth stage R1.6 and removed at 7-d intervals. The first 7 d of shade did not affect seed number, but 14 d of shade ending at roughly growth stage R3.0 reduced seed number by 16% and longer periods caused proportionally larger reductions. When shade cloth (80%) was put in place at 7-d intervals (starting at R3.4) and left in place until maturity, seed number was reduced until the last treatment (put in place 4-7 d after the beginning of growth stage R6). Seed number was tolerant of short periods (4-9 d) of low assimilate supply during flowering, but could not recover from longer periods of shade (≥14 d), even when they occurred relatively early in the flowering period.
  • Authors:
    • Ferreira, A. C. de B.
    • Lamas, F. M.
  • Source: Revista Ceres
  • Volume: 57
  • Issue: 6
  • Year: 2010
  • Summary: The objective of this work was to evaluate the production, persistence and the effect of different cover crops on weed control and cotton yield in no-tillage system. The treatments included: Pennisetum glaucum; Brachiaria ruziziensis; Sorghum bicolor; Eleusine coracana; Crotalaria juncea; Crotalaria spectabilis; Avena strigosa; Raphanus sativus; P. glaucum+ C. juncea; P. glaucum+ C. spectabilis; B. ruziziensis+ C. juncea; B. ruziziensis+ C. spectabilis; S. bicolor+ C. juncea; S. bicolor+ C. spectabilis; E. coracana+ C. juncea; E. coracana+ C. spectabilis; A. strigosa+ R. sativus; P. glaucum+ R. sativus; fallow. The cover crops were sown in late summer, after soybean harvest. The cotton cultivar BRS 269-Buriti was sown nine months later. The experiment was carried out in a randomized complete block design with four replications. Dry matter of B. ruziziensis, B. ruziziensis+ C. juncea, B. ruziziensis+ C. spectabilis and P. glaucum+ R. sativus was above 6.8 t ha -1 The dry matter produced by B. ruziziensis provided sufficient soil cover during the cotton cycle. Residues of B. ruziziensis, B. ruziziensis+ C. juncea and B. ruziziensis+ C. spectabilis reduced weed incidence until the time of cotton sowing, lasting until the initial stages of cotton development. The use of both R. sativus and A. strigosa, alone or in mixtures, resulted in reduced yield of cotton fiber.
  • Authors:
    • Paulino, J.
    • Zolin, C. A.
    • Folegatti, M. V.
    • Sanchez-Roman, R. M.
    • Bezerra, M. O.
  • Source: Informe Agropecuario
  • Volume: 31
  • Issue: 259
  • Year: 2010
  • Summary: Irrigation is important in the context of food, since each irrigated hectare is equivalent to 3-ha of irrigation in physical productivity and 7-ha in economic productivity. Given this importance and the fact that Brazil has different water availability from other countries, there was an approach to irrigated agriculture in the country, considering the irrigated area at the regional and state based on 2006 Census of Agriculture. Brazil has currently an area of 4.45 million hectares cultivated with irrigation being the largest irrigating the Southeast Region, followed by the South, Northeast, Midwest and Northeast. Among the crops, sugar cane, rice, soyabeans and maize stand out in irrigated area. The irrigation method used is more for sprinkling (no pivot), followed by flood, centre pivot, and located in the groove.