• Authors:
    • Sousa, D. M. G. de
    • Rein, T. A.
  • Source: Informações Agronômicas
  • Issue: 126
  • Year: 2009
  • Summary: Soyabean monoculture with inadequate agricultural practices has resulted in losses of soil organic matter in the Brazilian cerrado, especially in sandy soils. This has led to erosion, reduced cation exchange capacity and water storage, and diminished fertilizer use efficiency. One of the ways of avoiding the loss of soil organic matter is to reduce tillage, as in the system of direct (as opposed to conventional) planting, and the use of this system is growing in the cerrado region. This paper reviews work that has been done on the correction of soil acidity and fertilizing with macronutrients in the direct planting system, both before and after crop establishment. The section on soil acidity discusses both surface (0-20 cm) and subsurface (20-60 cm) acidity, and the effects of correction with limestone or gypsum under conventional and no tillage systems, and on cotton and soyabean yields under a direct planting system. The section on fertilizers looks at the effects of liming, conventional and no tillage systems and dry farming on soil macronutrient content (with particular reference to nitrogen, phosphorus and potassium) and crop yield (with data for maize). Soil organic matter content is also compared under conventional and no tillage systems.
  • Authors:
    • Ranamukhaarachchi, S.
    • Thongsaga, K.
  • Source: Asia-Pacific Journal of Rural Development
  • Volume: 19
  • Issue: 1
  • Year: 2009
  • Summary: Water stress is unpredictable in rain-fed agriculture, and regularly affects maize production in Thailand. This study was conducted to determine the effect of 10-day dry period occurring during critical growth stages on growth and yield of maize, and to simulate and compare the performance using CERES-Maize model in DSSAT version 4.0.2.0 using concurrent weather data. Two popular maize hybrids, namely Suwan 4452 and Pacific 224, were subjected to four 10-day dry periods [viz. 36-45 days from seeding (DFS), 46-55 DFS, 56-65 DFS, and 66-75 DFS] as treatments together with a control grown with regular irrigation in a split plot design with four replicates. The experiment was conducted during the longest dry period, from December 2006 to April 2007, under controlled irrigation. Soil moisture content at 0-15 cm and 15-30 cm depths reached near the lower limit of readily available water (RAW) in six days, after the cessation of irrigation, which declined to near permanent wilting point (PWP), but did not reach PWP during the 10-day period. Leaf area index (LAI) (ranged from 4.3 to 4.6), plant height (ranged from 2.2 to 2.4 m) and biomass (ranged from 6.8 to 7.6 t/ha) at silking were not significantly affected by the 10-day suspension of irrigation, but various differences were observed in the plant height: Suwan 4452 was taller than Pacific 224. Number of grains per ear, 100-grain weight, grain yield and the harvest index remained unaffected due to the 10-day suspension of irrigation, but were significantly greater in Pacific 224 than Suwan 4452. CERES-Maize model showed excellent results in predicting time to silking, LAI and biomass at silking, 100-grain weight, grain yield and the harvest index. However, some deviations were found in Suwan variety for LAI and 100-grain weight, and of Pacific 224 in the time to silking. Comparisons showed that simulations were very much close, except for the cases noted. The model simulated responses similar to the actual values in this study.
  • Authors:
    • Andreotti, M.
    • Benett, C. G. S.
    • Buzetti, S.
    • Valderrama, M.
    • Arf, O.
    • Sa, M. E. de
  • Source: Pesquisa Agropecuaria Tropical
  • Volume: 39
  • Issue: 3
  • Year: 2009
  • Summary: The objective of this study was to evaluate the effect of doses and sources of nitrogen and phosphorus, on the production components and grain yield, on irrigated common beans cultivated in a Cerrado area of Selviria, Mato Grosso do Sul State, Brazil (20degrees22′S, 51degrees22′W, altitude 335 m). The experimental design was a randomized block, with 4 doses of top-dressed N (0 kg ha -1, 40 kg ha -1, 80 kg ha -1, and 120 kg ha -1) and 2 sources (urea and coated urea), and 4 doses of phosphorus (0 kg ha -1, 50 kg ha -1, 100 kg ha -1, and 150 kg ha -1 of P 2O 5) and 2 sources (triple super phosphate and coated triple super phosphate), at sowing, with 4 repetitions. Nitrogen and phosphorus content in leaves, pod/plant number, grain/plant number, mass of 100 grains, and grain yield were evaluated. The sources of N, as well as the sources of P 2O 5, did not differ, as related to the number of pods per plant, grains per plant, mass of 100 grains, and grain yield. The doses of N influenced linearly the leaf N content, as well as the grain yield. The doses of P increased linearly the leaf P content and the grain yield, up to the 120 kg ha ′1 dose.
  • Authors:
    • Kreuzer, M.
    • Wettstein, H.
    • Gomez, C.
    • Gamarra, J.
    • Bartl, K.
    • Hess, H.
  • Source: Grass and Forage Science
  • Volume: 64
  • Issue: 2
  • Year: 2009
  • Summary: The agronomic performance and nutritive value of twelve annual and perennial grasses and legumes were analysed in order to define alternatives to local forages for dry-season feeding of ruminants in the Peruvian Andes. There were twelve species and two fertilizer treatments (no fertilizer and a N;P;K fertilizer mainly applied at sowing) in an experiment with a randomized complete block design with three replicates at each of two sites. Plant height, soil cover by forage and weed species, frost damage, dry matter (DM) yield and nutritive value of herbage were evaluated in 2005 and 2006. Among the annual species, Hordeum vulgare L. cv. UNA 80 and * Triticosecale Wittm. had the highest DM yields when fertilized (8226 and 6934 kg ha -1 respectively). Without fertilizer the alternative cultivars had similar DM yields to that of the local forages. Cultivars of Avena sativa L. had lower concentrations of neutral-detergent fibre (NDF) (557 g kg -1 DM) and higher concentrations of predicted net energy for lactation (5.86 MJ kg -1 DM) than the other annual grass species (625 g kg -1 DM and 5.01 MJ kg -1 DM respectively), while the legumes were superior in concentrations of crude protein (277 g kg -1 DM) and NDF (362 g kg -1 DM). Considering the low agronomic performance of the perennial forages, a mixture of fertilized annual grasses and legumes appears the most appropriate approach to meeting the demand for forage of high nutritive value in the Peruvian highlands.
  • Authors:
    • Cabezas, W. A. R. L.
    • Lange, A.
    • Trivelin, P. C. O.
  • Source: Revista Brasileira de Milho e Sorgo
  • Volume: 8
  • Issue: 1
  • Year: 2009
  • Summary: Strategies aiming to increase straw production by crops should be implemented in the Cerrado region in order to consolidate no-tillage cultivation. The objective of the present work was to evaluate the effect of time and splitting of supplementary nitrogen application to maize (in addition to the N-fertilization at seeding) on straw production and several yield components of black oat, a spontaneous native species. Treatments consisted of applying 70 kg ha -1 nitrogen in addition to maize fertilization at seeding, at distinct times: at black-oat seeding; 8 days before corn seeding; in covering in plants in the phases of 4-5 leaves and 6-7 leaves. At seeding, 42 kg N.ha -1 were applied in all plots. The nitrogen fertilization applied at oat seeding did not cause increase in out-of-season straw productivity. An increase in maize straw production was observed with nitrogen supply in addition to fertilization at seeding as well as the application closer to seeding resulted in an increased straw production when compared to fertilization at oat seeding.
  • Authors:
    • Sanginga, N.
    • Olufajo, O.
    • Iwuafor, E.
    • Abaidoo, R.
    • Yusuf, A.
  • Source: Agriculture, Ecosystems & Environment
  • Volume: 129
  • Issue: 1/3
  • Year: 2009
  • Summary: Understanding changes in soil chemical and biological properties is important in explaining the mechanism involved in the yield increases of cereals following legumes in rotation. Field trials were conducted between 2003 and 2005 to compare the effect of six 2-year rotations involving two genotypes each of cowpea (IT 96D-724 and SAMPEA-7) and soybean (TGx 1448-2E and SAMSOY-2), a natural bush fallow and maize on soil microbial and chemical properties and yield of subsequent maize. Changes in soil pH, total nitrogen (N tot), organic carbon (C org), water soluble carbon (WSC), microbial biomass carbon (C mic) and nitrogen (N mic) were measured under different cropping systems. Cropping sequence has no significant ( P>0.05) effect on soil pH and C org, while WSC increased significantly when maize followed IT 96D-724 (100%), SAMPEA-7 (95%), TGx 1448-2E (79%) and SAMSOY-2 (106%) compared with continuous maize. On average, legume rotation caused 23% increase in N tot relative to continuous maize. The C mic and N mic values were significantly affected by cropping sequence. The highest values were found in legume-maize rotation and the lowest values were found in fallow-maize and continuous maize. On average, C mic made up to 4.8% of C org and N mic accounted for 4.4% of N tot under different cropping systems. Maize grain yield increased significantly following legumes and had strong positive correlation with C mic and N mic suggesting that they are associated with yield increases due to other rotation effects. Negative correlation of grain yield with C mic:N mic and C org:N tot indicate that high C:N ratios contribute to nitrogen immobilization in the soil and are detrimental to crop productivity. The results showed that integration of grain legumes will reverse this process and ensure maintenance of soil quality and maize crop yield, which on average, increased by 68% and 49% following soybean and cowpea, respectively compared to continuous maize.
  • Authors:
    • Tennigkeit, T.
    • Woelcke, J.
  • Source: Rural21: The International Journal for Rural Development
  • Issue: 01
  • Year: 2009
  • Summary: The smallholder agricultural sector in East Africa can substantially contribute to climate change mitigation, generate carbon revenues for farmers, and enhance agrobiodiversity, while reducing farmers' vulnerability to climate change. Currently a demonstration project is being developed with support of the World Bank which will generate emission reductions based on the adoption of sustainable agricultural land management practices.
  • Authors:
    • Eckard, R.
    • Henry, B.
  • Source: Tropical Grasslands
  • Volume: 43
  • Year: 2009
  • Summary: Agriculture is responsible for a significant proportion of total anthropogenic greenhouse gas emissions (perhaps 18% globally), and therefore has the potential to contribute to efforts to reduce emissions as a means of minimising the risk of dangerous climate change. The largest contributions to emissions are attributed to ruminant methane production and nitrous oxide from animal waste and fertilised soils. Further, livestock, including ruminants, are an important component of global and Australian food production and there is a growing demand for animal protein sources. At the same time as governments and the community strengthen objectives to reduce greenhouse gas emissions, there are growing concerns about global food security. This paper provides an overview of a number of options for reducing methane and nitrous oxide emissions from ruminant production systems in Australia, while maintaining productivity to contribute to both objectives. Options include strategies for feed modification, animal breeding and herd management, rumen manipulation and animal waste and fertiliser management. Using currently available strategies, some reductions in emissions can be achieved, but practical commercially available techniques for significant reductions in methane emissions, particularly from extensive livestock production systems, will require greater time and resource investment. Decreases in the levels of emissions from these ruminant systems (i.e., the amount of emissions per unit of product such as meat) have already been achieved. However, the technology has not yet been developed for eliminating production of methane from the rumen of cattle and sheep digesting the cellulose and lignin-rich grasses that make up a large part of the diet of animals grazing natural pastures, particularly in arid and semi-arid grazing lands. Nevertheless, the abatement that can be achieved will contribute significantly towards reaching greenhouse gas emissions reduction targets
  • Authors:
    • Hunt, J. R.
    • Dalgliesh, N. P.
    • McCown, R. L.
    • Whish, J. P. M.
    • Robertson, M. J.
    • Foale, M. A.
    • Poulton, P. L.
    • Rees, H. van
    • Carberry, P. S.
    • Hochman, Z.
  • Source: Crop & Pasture Science
  • Volume: 60
  • Issue: 11
  • Year: 2009
  • Summary: Crop simulation models relevant to real-world agriculture have been a rationale for model development over many years. However, as crop models are generally developed and tested against experimental data and with large systematic gaps often reported between experimental and farmer yields, the relevance of simulated yields to the commercial yields of field crops may be questioned. This is the third paper in a series which describes a substantial effort to deliver model-based decision support to Australian farmers. First, the performance of the cropping systems simulator, APSIM, in simulating commercial crop yields is reported across a range of field crops and agricultural regions. Second, how APSIM is used in gaining farmer credibility for their planning and decision making is described using actual case studies. Information was collated on APSIM performance in simulating the yields of over 700 commercial crops of barley, canola, chickpea, cotton, maize, mungbean, sorghum, sugarcane, and wheat monitored over the period 1992 to 2007 in all cropping regions of Australia. This evidence indicated that APSIM can predict the performance of commercial crops at a level close to that reported for its performance against experimental yields. Importantly, an essential requirement for simulating commercial yields across the Australian dryland cropping regions is to accurately describe the resources available to the crop being simulated, particularly soil water and nitrogen. Five case studies of using APSIM with farmers are described in order to demonstrate how model credibility was gained in the context of each circumstance. The proposed process for creating mutual understanding and credibility involved dealing with immediate questions of the involved farmers, contextualising the simulations to the specific situation in question, providing simulation outputs in an iterative process, and together reviewing the ensuing seasonal results against provided simulations. This paper is distinct from many other reports testing the performance and utility of cropping systems models. Here, the measured yields are from commercial crops not experimental plots and the described applications were from real-life situations identified by farmers. A key conclusion, from 17 years of effort, is the proven ability of APSIM to simulate yields from commercial crops provided soil properties are well characterised. Thus, the ambition of models being relevant to real-world agriculture is indeed attainable, at least in situations where biotic stresses are manageable.
  • Authors:
    • Shankar, M. A.
    • Murukannappa
    • Gajanan, G. N.
    • Ganapathi
  • Source: Environment and Ecology
  • Volume: 27
  • Issue: 2
  • Year: 2009
  • Summary: A long term field experiment was conducted on cereal-legume cropping sequence leaving summer fallow at Bangalore during 1993 to 2006 in light textured red sandy loam soil to study the effect of long term use of glyricidia, farm yard manure and NPK fertilizers on soil fertility, crop productivity and nutrients losses. Plots of 3,000 m 2 each and having 2.5% slopes were delineated for each treatment. Appropriate instrumentation was done to quantity the nutrients loss. Continuous use of glyricidia to supply recommended N+50% recommended NPK recorded 16.8 and 142.6% higher yield followed by FYM and NPK in equal proportion (3.22 and 88.6%) in fingermillet and maize respectively as compared to recommended NPK (2,572 kg/ha and 1,150 kg/ha). FYM and 50% NPK recorded 35.8% higher soybean yield followed by FYM with 25.6% as compared to recommended NPK (453 kg/ha). Highest loss of OM, N, P and K were recorded under control and lowest losses were recorded in FYM and NPK in equal proportion, but least P loss (0.39 kg/ha) was recorded with 50% N with through glyricidia+50% NPK. In soybean, highest loss of OM, N, P and K were recorded in control and least loss of OM, P and K in FYM to supply 50% N+50% NPK. But least loss of N was in glyricidia to supply 50%+50% recommended NPK. In maize, highest loss of OM, N, P and K were recorded in control followed by recommended NPK. Irrespective of the crops the mean of seven years indicated that highest loss of OM, N, P and K were under control treatment Least loss of OM and N occurred under glyricidia to supply 50%+50% recommended NPK. But least losses P and K were recorded in NPK. Analysis of surface soil samples (0-15 cm) indicated that continuous addition of FYM or glyricidia to supply recommended N alone or along with NPK over a period of 13 years increased OC, biomass carbon and mean weight diameter as compared to NPK alone. Reduction in soil pH in recommended NPK from 5.6 to 4.5 and improvement in organics, increased available N, available K, sulfur, Zn, Cu Mn and Fe in organics alone or along with NPK as compared to recommended NPK.