• Authors:
    • Blaise, D.
  • Source: Soil & Tillage Research
  • Volume: 114
  • Issue: 2
  • Year: 2011
  • Summary: Transgenic Bt cotton hybrids, in India, now constitute more than 90% of the cotton area. Conservation tillage systems such as reduced tillage (RT) improve soil health and crop productivity. Field experiments were conducted to study the response of Bt cotton hybrids to the tillage methods in a split plot design for three years (2005-2006 to 2007-2008) with tillage practices as main plots (conventional tillage {CT}, RT with two inter-row cultivations {RT(1)} and RT with no inter-row cultivation {RT(2)}). In the sub-plot, in situ green manure (GM) was included along with 100 (GM + N(100)), 80 (GM + N(80)) and 60 kg N ha(-1) (GM + N(60)) and were compared to N alone (N(100)). Growth, yield and fibre quality of Bt transgenic cotton hybrid (RCH-2 Bt) were monitored during the study. In all seasons, weed density and biomass were significantly lower in the RT treatments than in the CT treatments. Taller plants with more main stem nodes were produced on the RT plots (63.6-75.8 cm) than on the CT plots (58.1-70.2 cm). Thus, plants of RT treatment retained more bolls (60.8-62.0 m(-2)) than those of the CT treatment (52.4 m(-2)). Averaged over seasons, RT treatment had seed cotton yield (1717-1740 kg ha(-1)) significantly higher than the CT treatment (1489 kg ha(-1)). The treatments N(100), GM + N(100) and GM + N(80) (1687-1734 kg ha(-1)) did not differ and were significantly better than the GM + N(60) (1303 kg ha(-1)). Tillage x GM interaction was significant in two of three years and data combined over years. The RT plots with GM had significantly greater yield than the CT plots. Compared to the CT treatment, the RT plots had significantly greater proportion of water stable aggregates (48.6% vs. 54.4-56.0%) and mean weight diameter (0.47 mm vs. 0.49-0.51 mm). The GM plots had significantly higher WSA and MWD than those without. Further, soil moisture content was greater in the GM mulched plots up to 0.60 m depth compared to without GM treatment (CT + N(100)). Favourable soil physical properties may have contributed to improved seed cotton yield in the RT treatments with GM than in the CT treatment. Fibre quality was not affected by either the tillage systems or GM. This study indicates that Bt transgenic cotton can be grown under RT systems with an in situ legume GM. (C) 2011 Elsevier B.V. All rights reserved.
  • Authors:
    • Nogueira, C. C. P.
    • Veloso, M. E. da C.
    • Freire Filho, F. R.
    • Cardoso, M. J.
    • Blanco, F. F.
    • Dias, N. da S.
  • Source: Pesquisa Agropecuária Brasileira
  • Volume: 46
  • Issue: 5
  • Year: 2011
  • Summary: The objective of this work was to evaluate the response of green maize ( Zea mays) intercropped with cowpea ( Vigna unguiculata) to irrigation depths and phosphorus doses. The experiments were carried out in 2008 and 2009 in a randomized block design, with 25 treatments and four replicates. Treatments consisted of five irrigation depths at 70, 110, 140, 180 and 220% of the crop evapotranspiration, and of five doses of P 2O 5: 0, 50, 100, 150 and 200% of the recommended P dose. Maize was sown at 0.80*0.40 m spacing, and cowpea was planted inside the lines among maize plants. There was no effect of P 2O 5 doses, but the response to irrigation depths was quadratic for maize and linear for cowpea. The maximum technical yield of green ears of maize with straw (10.76 Mg ha -1) and without straw (7.62 Mg ha -1) was obtained with 530 mm depth, intermediary to the 180 and 220% of the crop evapotranspiration. The highest cowpea green grain (3.40 Mg ha -1) was obtained with the highest water depth, of 644 mm.
  • Authors:
    • Ouedraogo, E.
    • Mando, A.
  • Source: Proceedings of the 19th World Congress of Soil Science: Soil Solutions for a Changing World
  • Year: 2010
  • Summary: A field experiment was conducted in Gampela (Burkina Faso) in 2000 and 2001 to assess the impact of organic and mineral sources of nutrients and combinations thereof in optimizing crop production under till and no-till and to assess the economic benefit of that option. At a dose equivalent to 40 kg N/ha, crop yield was better secured with organic-N than with urea-N. Combining organic and mineral sources of nutrients do not have only additive effects but real interaction, which significantly affect crop yield and water use efficiency. The use of soil and water management measures is a key to increase the economic benefit of mineral, organic or combined organic and mineral sources of nutrient application under semi-arid conditions.
  • Authors:
    • Huon, S.
    • Soulileuth, B.
    • Jouquet, P.
    • Pierret, A.
    • Ribolzi, O.
    • Valentin, C.
    • Bourdon, E.
    • Chantharath, B.
    • Rouw, A. de
  • Source: Agriculture, Ecosystems & Environment
  • Volume: 136
  • Issue: 1-2
  • Year: 2010
  • Summary: There is limited information, particularly in the tropics, of farming systems that loose or accumulate carbon in their soils. We compared no-till with a mulch-providing cover crop with conventional tillage without cover crop. Side effects were also investigated, weeds, surface crusting, soil macrofauna, infiltration, porosity and roots. The study site was a flat sandy clay loam. Treatments were maintained over five years; within this period, the time between the first and last soil sampling was exactly four years. Both times the same profile locations and exactly the same depths were sampled thereby greatly reducing inherent soil variability. Soil was sampled at five increments from 0 to 40 cm depth. The biomass contributions of maize, cover crop and weeds were measured. The main findings were: (1) The cover crop that was alleged to supply extra inputs to the no-till system failed to do so because the weeds in the tillage treatment became as efficient in accumulating biomass as the planted cover crop. (2) With equal organic inputs over four years (43.0 Mg dry weight ha -1 incorporated into the soil under conventional tillage, and 44.2 Mg dry weight ha -1 remaining on the soil surface as mulch under no-till), the tillage system stored (0-40 cm) significantly soil carbon (+590 g C m -2), whereas the no-till lost carbon (-133 g C m -2). The difference between the systems was significant. Carbon accumulated just below the plough layer. Nitrogen stocks remained unchanged. A very significant lowering of the C:N ratio occurred under no-till. The process of transforming the available biomass on the soil surface into organic matter is apparently too slow to avoid direct losses under no-till. Alternatively, ploughing plant residues into the soil enables to capture some of what would otherwise be lost as CO 2 through decay, thereby increasing soil carbon. (3) In the last three years of the experiment, maize grain yields and crop residues stabilized at a lower level but were significantly higher under no-till, 16% and 34%, respectively. Higher yields were attributed to more soil water under no-till due to improved soil structure, though bulk density was not affected. The mulch layer protecting the soil surface favoured infiltration by keeping it crust-free. Water availability was further promoted by a better connectivity of pores and more macrofauna. However, the no-till system depended heavily on fertilizers and herbicides. The lack of effectiveness of herbicides against shifting weed communities threatens the continuation of the system.
  • Authors:
    • Mielniczuk, J.
    • Vezzani, F. M.
  • Source: Proceedings of the 19th World Congress of Soil Science: Soil solutions for a changing world
  • Year: 2010
  • Summary: Soil use for agricultural production may increase soil structure quality as long as conservation management practices are adopted. The aggregates and single particles distribution into diameter classes (9.51-4.76, 4.76-2.00, 2.00-0.25, 0.25-0.053, 0.25 mm) also were increased from 22.8% to 53.5% and the C stock reached 17.9 Mg/ha building a complex soil structure with the capacity to increase soil quality.
  • Authors:
    • Biradar, D. P.
    • Rathod, P. S.
    • Patil, V. C.
  • Source: Journal of Medicinal and Aromatic Plant Sciences
  • Volume: 32
  • Issue: 4
  • Year: 2010
  • Summary: A field experiment was conducted at Regional Agricultural Research Station, Bijapur on medium deep black soil during rabi seasons of 2004 and 2005 to study the influence of different rabi intercrops on growth and productivity of senna. The treatment consists of five rabi crops (chickpea, safflower, linseed, mustard and wheat) and senna in sole stand as well as intercropping system and safflower+chickpea (2:4) intercropping system as a check. The sole crop of senna recorded significantly better growth and growth parameters as compared to intercropped senna. The leaf and pod yield of senna also followed the same trend as that of growth and growth parameters with different rabi intercrops. Growing of senna with safflower adversely reduced the growth and growth parameters, leaf and pod yield as compared to chickpea, linseed, mustard and wheat.
  • Authors:
    • Hayes, P.
    • Talbert, H.
    • Surber, L.
    • Kanazin, V.
    • Bowman, J.
    • Abdel-Haleem, H.
    • Blake, T.
  • Source: Euphytica
  • Volume: 172
  • Issue: 3
  • Year: 2010
  • Summary: More than half of the barley grown in the USA is used for livestock feed, with the remaining stocks diverted for human food and malting purposes. The use of barley grain as a major source of cattle feed has been criticized because of its rapid digestion in the rumen, which can result in digestive disorders in cattle. In sacco dry matter digestibility (ISDMD) and particle size (PS) after dry rolling have been found to play a role in the feedlot performance of barley as a feed grain. Reducing the rate of ISDMD is predicted to result in significantly improved animal health and average daily gain. A recombinant inbred line population derived from a cross between a high ISDMD, two-rowed barley cultivar (Valier) and a six-rowed Swiss landrace line (PI370970) exhibiting far slower ISDMD has been developed for studying the underlying genetic locations and mechanisms of these traits. To detect associated quantitative trait loci (QTLs), we collected and analyzed data from irrigated and rain-fed environments. A significant negative correlation was observed between ISDMD and PS. High heritability estimates for ISDMD and PS suggest that early selection for these traits during breeding would be achievable. Four QTLs were identified on chromosomes 2H, 6H, and 7H, explaining 73-85% of ISDMD phenotypic variation, while three QTLs on 2H and 7H were associated with variation in PS and explained 58-77% of its variation. A major QTL on chromosome 2H tightly linked to the morphology-modifying gene vrs1 was found to dramatically control 35-62% of the phenotypic variation of ISDMD and 26-53% of that of PS. The impact of the vrs1 locus on ISDMD was validated in two populations representing different genetic backgrounds. Our results suggest that it may also be advantageous to simultaneously overlap these QTLs around the vrs1 locus.
  • Authors:
    • Rayar, A. J.
    • Senthivel, T.
    • Kannan, N.
    • Frank, M.
  • Source: Agricultural Water Management
  • Volume: 97
  • Issue: 5
  • Year: 2010
  • Summary: The study explores the potential of introducing an additional crop during dry season in Rwanda, comparing the efficiency of in situ soil moisture conservation techniques to sustain rain-fed agriculture. Comparative study of in situ soil moisture conservation techniques in bench terraces and unterraced field with maize crop had been conducted from June 2007 to October 2007. Bench terrace increased the average soil moisture content in 90 cm soil depth by more than 50% than that of unterraced land. Within the bench terraced field compartment bund and ridges and furrows increased soil moisture by 19.5% and 27.9% higher than plain bed. In terms of efficiency of moisture conservation, ridges and furrows performed well with 85.8% followed by compartment bund with 75.9% in terraced field. Unterraced field conserved moisture very poorly with 13.9% efficiency inferring importance of bench terraces for soil moisture conservation. No maize grain yield was recorded in all the techniques because soil water depleted to 60% and above from the beginning of the cropping period inferring the need of supplementary irrigation. Analysis of rainfall, crop water demand and in situ moisture conservation reveals exciting opportunities for water productivity enhancements by integrating components of water management within the context of rain-fed farming through water harvesting and supplemental or microirrigation for dry spell mitigation. Detailed analysis is needed for feasibility of lift irrigation with different crops under different altitudes to derive suitable policy for hill land irrigation.
  • Authors:
    • Kumar, S. N.
    • Byjesh, K.
    • Aggarwal, P. K.
  • Source: Mitigation and Adaptation Strategies for Global Change
  • Volume: 15
  • Issue: 5
  • Year: 2010
  • Summary: Climate change associated global warming, rise in carbon dioxide concentration and uncertainties in precipitation has profound implications on Indian agriculture. Maize ( Zea mays L.), the third most important cereal crop in India, has a major role to play in country's food security. Thus, it is important to analyze the consequence of climate change on maize productivity in major maize producing regions in India and elucidate potential adaptive strategy to minimize the adverse effects. Calibrated and validated InfoCrop-MAIZE model was used for analyzing the impacts of increase in temperature, carbon dioxide (CO 2) and change in rainfall apart from HadCM3 A2a scenario for 2020, 2050 and 2080. The main insights from the analysis are threefold. First, maize yields in monsoon are projected to be adversely affected due to rise in atmospheric temperature; but increased rainfall can partly offset those loses. During winter, maize grain yield is projected to reduced with increase in temperature in two of the regions (Mid Indo-Gangetic Plains or MIGP, and Southern Plateau or SP), but in the Upper Indo-Gangetic Plain (UIGP), where relatively low temperatures prevail during winter, yield increased up to a 2.7°C rise in temperature. Variation in rainfall may not have a major impact on winter yields, as the crop is already well irrigated. Secondly, the spatio-temporal variations in projected changes in temperature and rainfall are likely to lead to differential impacts in the different regions. In particular, monsoon yield is reduced most in SP (up to 35%), winter yield is reduced most in MIGP (up to 55%), while UIGP yields are relatively unaffected. Third, developing new cultivars with growth pattern in changed climate scenarios similar to that of current varieties in present conditions could be an advantageous adaptation strategy for minimizing the vulnerability of maize production in India.
  • Authors:
    • Kalungu, J. W.
    • Monteiro, R. O. C.
    • Coelho, R. D.
  • Source: Ciência Rural
  • Volume: 40
  • Issue: 10
  • Year: 2010
  • Summary: This paper reviews various irrigation technologies in both South Africa and Kenya that enable improvements in their socio-economic conditions. The two countries are located in semi-arid areas that experience extreme fluctuations in the availability of rain water for plant growth. Population growth exceeds the ability to produce food in numerous countries around the world and the two countries are not an exception. This experiment examined the constraints that farmers face and the role of government and nongovernmental organization in the uptake of modern technologies for irrigation. Detailed mechanisms and options to secure sustainable irrigation which are economically viable are considered. Despite the higher production of cereals and grains, fruits, and flowers also thrive in the two countries. Total irrigated area, crops grown and irrigation systems used in the two countries are discussed.