• Authors:
    • Kumar, V.
    • Kumar, V.
    • Saharawat, Y. S.
    • Ladha, J. K.
    • Gathala, M. K.
    • Sharma, P. K.
  • Source: Soil Science Society of America Journal
  • Volume: 75
  • Issue: 5
  • Year: 2011
  • Summary: Rice-wheat (Oryza sativa L.-Triticum aestivum L.) rotation is the major production system in Asia, covering about 18 million ha. Conventional practice of growing rice (puddled transplanting) and wheat (conventional till, CT) deteriorate soil physical properties, and are input- and energy-intensive. Zero-tillage (ZT) along with drill-seeding have been promoted to overcome these problems. A 7-yr permanent plot study evaluated various tillage and crop establishment (CE) methods on soil physical properties with an aim to improve soil health and resource-use efficiency. Treatments included transplanting and direct-seeding of rice on flat and raised beds with or without tillage followed by wheat in CT and ZT soil. Bulk density (D(b)) of the 10- to 20-cm soil layer was highest under puddled treatments (1.74-1.77 Mg m(-3)) and lowest under ZT treatments (1.66-1.71 Mg m(-3)). Likewise, soil penetration resistance (SPR) was highest at the 20-cm depth in puddled treatments (3.46-3.72 MPa) and lowest in ZT treatments (2.51-2.82 MPa). Compared with conventional practice, on average, water-stable aggregates (WSAs) > 0.25 mm were 28% higher in ZT direct-seeding with positive time trend of 4.02% yr(-1). Infiltration was higher (0.29-0.40 cm h(-1)) in ZT treatments than puddled treatments (0.18 cm h(-1)). The least-limiting water range was about double in ZT direct-seeding than that of conventional practice. Gradual improvement in soil physical parameters in ZT system resulted in improvement in wheat yield and is expected to be superior in long-run on system (rice+wheat) basis. Further research is needed to understand mechanisms and requirements of two cereals with contrasting edaphic requirements in their new environment of ZT direct-seeding.
  • Authors:
    • Nagih, A.
    • Lemalade, J. L.
    • Alfandari, L.
    • Plateau, G.
  • Source: Annals of Operations Research
  • Volume: 190
  • Issue: 1
  • Year: 2011
  • Summary: We propose a Mixed-Integer Linear Programming model for a class of multi-period crop rotation optimization problems with demand constraints and incompatibility constraints between cultivation and fallow state on a land plot. This model is applied to a case study on Madagascan farms in the scope of a sustainable development campain against deforestation, where the objective is to better control agricultural space while covering seasonal needs of farmer. We propose an efficient upper bound computation and study the variation of the minimum number of plots and total space needed in function of the unitary surface area of a plot. Numerical results associated with the Madagascan case are reported.
  • Authors:
    • Peluzio, J. M.
    • Almeida, R. D. de
    • Afférri, F. S.
  • Source: Revista Ciência Agronômica
  • Volume: 42
  • Issue: 1
  • Year: 2011
  • Summary: The aim of this work was to evaluate the genetic divergence among twelve soybean cultivars under irrigated lowland conditions in south Tocantins State, Brazil, in the Companhia Brasileira de Agropecuaria (COBRAPE), at Formoso do Araguaia, TO, in the inter-cropping 2005. The experimental design employed was randomized blocks with twelve treatments and tree replications. The treatments consisted on the following cultivars: DM Vitoria, MG/BR 46 (Conquista), Suprema, BRS Pintado, DM 247, BRS/MG 68, BRS/MG Lideranca, BRS MG Seguranca, DM 339, BRS/MG Garantia, A 7002, and DM 309. The following characteristics were evaluated: grain yield, weight of hundred seeds, number of seeds per pod, number of pods per plant, number of days for flowering; number of days for maturation, plant height and height insertion of the primary pod. Genetic divergence was evaluated by multivariate procedures: generalized Mahalanobis distance, Tocher's agglomerative method of Tocher and nearest neighbor. The Tocher's method and nearest neighbor agreed among themselves. Number of days for the maturation (39.49%), weigh of hundred seeds (26.56%) and number of days for flowering (13.59%) were the traits that most contributed to the genetic dissimilarity. The presence of genetic variability allowed the identification of dissimilar cultivars with high average for the traits studied. BRS/MG Garantia * DM 339 and BRS/MG Garantia * MG/BR 46 (Conquista) hybridizations are promising for obtaining segregate populations with higher variability.
  • Authors:
    • Gautam, M.
    • Ambati, R. R.
    • Reddy, A. R.
  • Source: Indian Journal of Agronomy
  • Volume: 56
  • Issue: 4
  • Year: 2011
  • Summary: Field trials were conducted to validate farm pond sizes for supplemental irrigations during 2004-2011 at the Central Institute for Cotton Research, Nagpur (′21degrees09′N, 79degrees09′E.). Ten farm ponds 200 to 15,120 m 3 size resulted in a runoff storage of about 60, 75 and 28, 36, 58% (2007, 2010 and 2008, 2009, 2011) in normal and drought years at the end of August month. During actual drought the water availability was 0 and 18% only of the capacity designed in 2011 and 2008 July seedling droughts. Special recharging techniques like opening borewells/percolation tanks etc in under ground storages and using it with sprinkler irrigation during seedling droughts is the only option. Two supplemental irrigations at flowering stage along with application of deficient micronutrients on shallow and medium soils to Bt hybrid cotton ( G. hirsutum L.) resulted in increased seed cotton yield by 50% and 44%, which was verified during 2008 and 2009 seasons in Yeotmal district. The minimum economical catchment was found to be 21 ha or 0.7 ha m pond size, with which 25% and 50% area could be irrigated by conventional and alternate furrow/sprinkler irrigation respectively, with a payback period (PBP) of 2 years in Bt hybrid cotton. Rotational soybean ( Glycine max (L.) Merrill) could be irrigated to the extent of 16 and 33% catchment area with improved water use efficiency (WUE) from 250 to 500 kg/ha-cm for 1.5 and 3.5 years of pay back period (PBP) under conventional and sprinkler irrigation, respectively, during drought conditions. The same sprinkler and drip irrigation systems could also be used to irrigate subsequent wheat [ Triticum aestivum (L.) emend. Fiori & Paol] crop with a gravitational well, covering 14 and 57% of catchment area with WUE of 180 kg/ha-cm with a PBP of 11 and 21 years.
  • Authors:
    • Yawson, D. O.
    • Obiri, S.
    • Yengoh, G. T.
    • Odoi, J. O.
    • Armah, F. A.
    • Afrifa, E. K. A.
  • Source: Mitigation and Adaptation Strategies for Global Change
  • Volume: 16
  • Issue: 3
  • Year: 2011
  • Summary: Desertification, climate variability and food security are closely linked through drought, land cover changes, and climate and biological feedbacks. In Ghana, only few studies have documented these linkages. To establish this link the study provides historical and predicted climatic changes for two drought sensitive agro-ecological zones in Ghana and further determines how these changes have influenced crop production within the two zones. This objective was attained via Markov chain and Fuzzy modelling. Results from the Markov chain model point to the fact that the Guinea savanna agro-ecological zone has experienced delayed rains from 1960 to 2008 while the Sudan savanna agro-ecological zone had slightly earlier rains for the same period. Results of Fuzzy Modelling indicate that very suitable and moderately suitable croplands for millet and sorghum production are evenly distributed within the two agro-ecological zones. For Ghana to adapt to climate change and thereby achieve food security, it is important to pursue strategies such as expansion of irrigated agricultural areas, improvement of crop water productivity in rain-fed agriculture, crop improvement and specialisation, and improvement in indigenous technology. It is also important to encourage farmers in the Sudan and Guinea Savanna zones to focus on the production of cereals and legumes (e.g. sorghum, millet and soybeans) as the edaphic and climatic factors favour these crops and will give the farmers a competitive advantage. It may be necessary to consider the development of the study area as the main production and supply source of selected cereals and legumes for the entire country in order to free lands in other regions for the production of crops highly suitable for those regions on the basis of their edaphic and climatic conditions.
  • Authors:
    • Risede, J.-M.
    • Foster, J.
    • Rhodes, R.
    • Berry, S. D.
    • van Antwerpen, R.
  • Source: International Journal of Pest Management
  • Volume: 57
  • Issue: 4
  • Year: 2011
  • Summary: Plant-parasitic nematodes cause significant yield losses to sugarcane crops in South Africa. The currently available chemicals for nematode control are both expensive and potentially detrimental to the environment. Various alternative crops have been reported to reduce the numbers of plant-parasitic nematodes. Mindful of this, we evaluated 27 cover crops in pot trials to assess their host status to important plant-parasitic nematodes of sugarcane. All of the crops tested in pots hosted significantly lower numbers of Pratylenchus than did sugarcane. Crops such as cowpeas, tomato and grazing vetch were good hosts for Meloidogyne and would not be good choices as part of a sugarcane rotation system in heavily-infested soils. Conversely, crops such as oats, wheat, forage peanuts and marigolds reduced numbers of Meloidogyne. Velvet beans increased the abundance of Helicotylenchus, a beneficial nematode genus. A field trial was also conducted to study the effect of different cover cropping sequences. Our results show that changes in nematode communities occurred within three months of growing these crops and often remained low for the duration (the remaining 15 months) of the crops' growth. Nematodes such as Pratylenchus and Tylenchorhynchus were significantly lowered and remained so for the duration of the trial.
  • 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.