• 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.
  • Authors:
    • Bosque-Pérez, N. A.
    • Eigenbrode, S. D.
    • Hatten, T. D.
    • Johnson-Maynard, J. L.
    • Umiker, K. J.
  • Source: Soil & Tillage Research
  • Volume: 105
  • Issue: 2
  • Year: 2009
  • Summary: Farmers within the Inland Pacific Northwest are gradually transitioning to direct seed (DS) practices that reduce soil disturbance and increase surface residue compared to conventional tillage (CT). Despite this transition the impacts of DS practices on soil properties and fauna in commercial fields has been little studied in the region. During the spring and summer of 2002 and 2003 we compared soil organic carbon (SOC), total nitrogen (TN), pH, and earthworm and cocoon densities in CT and DS fields planted to either spring wheat or pea in the Palouse region of northern Idaho. In 2002 mean SOC within the 0-10-cm depth was greater in DS fields (2.05%) than at the same depth in CT fields (1.79%), however SOC within the 30-40-cm depth was lower under DS compared to CT. Mean soil pH within the 0-10-cm depth was 5.35 under DS and 5.61 under CT indicating that pH stratification can occur when tillage is reduced. Tillage effects on SOC, TN, and pH were not found in 2003. Tillage also did not significantly influence earthworm densities, which averaged 39 individuals m-2 in 2002 and 57 individuals m-2 in 2003. Correlations were detected in 2003 DS fields between soil properties (SOC and TN) and earthworm and cocoon densities at depths above 30 cm while in 2002 correlations in DS fields occurred with cocoon density, but not with earthworm density. Direct seed management can increase near-surface SOC and TN concentrations compared to CT practices, however, SOC concentrations deeper in the soil appear to remain the same or possibly decrease. Higher SOC and TN near the soil surface, as found in DS fields, appear to promote greater earthworm densities, which may improve long-term soil productivity.
  • Authors:
    • Lal, R.
  • Source: Soil & Tillage Research
  • Volume: 102
  • Issue: 2
  • Year: 2009
  • Summary: Global energy demand of 424 EJ year-1 in 2000 is increasing at the rate of 2.2% year-1. There is a strong need to increase biofuel production because of the rising energy costs and the risks of global warming caused by fossil fuel combustion. Biofuels, being C-neutral and renewable energy sources, are an important alternative to fossil fuels. Therefore, identification of viable sources of biofuel feedstock is a high priority. Harvesting lignocellulosic crop residues, especially of cereal crops, is being considered by industry as one of the sources of biofuel feedstocks. Annual production of lignocellulosic residues of cereals is estimated at 367 million Mg year-1 (75% of the total) for the U.S., and 2800 million Mg year-1 (74.6% of the total) for the world. The energy value of the residue is 16 × 106 BTU Mg-1. However, harvesting crop residues would have strong adverse impact on soil quality. Returning crop residues to soil as amendments is essential to: (a) recycling plant nutrients (20-60 kg of N, P, K, Ca per Mg of crop residues) amounting to 118 million Mg of N, P, K in residues produced annually in the world (83.5% of world's fertilizer consumption), (b) sequestering soil C at the rate of 100-1000 kg C ha-1 year-1 depending on soil type and climate with a total potential of 0.6-1.2 Pg C year-1 in world soils, (c) improving soil structure, water retention and transmission properties, (d) enhancing activity and species diversity of soil fauna, (e) improving water infiltration rate, (f) controlling water runoff and minimizing risks of erosion by water and wind, (g) conserving water in the root zone, and (h) sustaining agronomic productivity by decreasing losses and increasing use efficiency of inputs. Thus, harvesting crop residues as biofuel feedstock would jeopardize soil and water resources which are already under great stress. Biofuel feedstock must be produced through biofuel plantations established on specifically identified soils which do not compete with those dedicated to food crop production. Biofuel plantations, comprising of warm season grasses (e.g., switch grass), short rotation woody perennials (e.g., poplar) and herbaceous species (e.g., miscanthus) must be established on agriculturally surplus/marginal soils or degraded/desertified soils. Plantations established on such soils would restore degraded ecosystems, enhance soil/terrestrial C pool, improve water resources and produce biofuel feedstocks.
  • Authors:
    • Moreno, F.
    • Murillo, J. M.
    • López-Garrido, R.
    • Melero, S.
  • Source: Soil & Tillage Research
  • Volume: 104
  • Issue: 2
  • Year: 2009
  • Summary: Short- and long-term field experiments are necessary to provide important information about how soil carbon sequestration is affected by soil tillage system; such systems can also be useful for developing sustainable crop production systems. In this study, we evaluated the short- and long-term effects of conservation tillage (CT) on soil organic carbon fractions and biological properties in a sandy clay loam soil. Both trials consisted of rainfed crop rotation systems (cereal-sunflower-legumes) located in semi-arid SW Spain. In both trials, results were compared to those obtained using traditional tillage (TT). Soil samples were taken in flowering and after harvesting of a pea crop and collected at three depths (0-5, 5-10 and 10-20 cm). The soil organic carbon fractions were measured by the determination of total organic carbon (TOC), active carbon (AC) and water soluble carbon (WSC). Biological status was evaluated by the measurement of soil microbial biomass carbon (MBC) and enzymatic activities [dehydrogenase activity (DHA), o-diphenol oxidase activity (DphOx), and beta-glucosidase activity (beta-glu)]. The contents of AC and MBC in the long-term trial and contents of AC in the short-term trial were higher for CT than TT at 0-5 cm depth for both sampling periods. Furthermore, DHA and beta-glucosidase values in the July sampling were higher in the topsoil under conservation management in both trials (short- and long-term). The parameters studied tended to decrease as depth increased for both tillage system (TT and CT) and in both trials with the exception of the DphOx values, which tended to be higher at deeper layers. Values of DHA and beta-glu presented high correlation coefficients (r from 0.338 to 0.751, p <= 0.01) with AC, WSC and TOC values in the long-term trial. However, there was no correlation between either TOC or MBC and the other parameters in the short-term trial. In general, only stratification ratios of AC were higher in CT than in TT in both trials. The results of this study showed that AC content was the most sensitive and reliable indicator for assessing the impact of different soil management on soil quality in the two experiments (short- and long-term). Conservation management in dryland farming systems improved the quality of soil under our conditions, especially at the surface layers, by enhancing its storage of organic matter and its biological properties, mainly to long-term. (C) 2009 Elsevier B.V. All rights reserved.
  • Authors:
    • Pepo, P.
  • Source: Analele Universităţii din Oradea, Fascicula: Protecţia Mediului
  • Volume: 14
  • Year: 2009
  • Summary: In non-irrigated treatment the maximum yields of winter wheat were 5590 kg ha -1 in biculture (maize-wheat) and 7279 kg ha -1 in triculture (peas-wheat-maize) in 2007 year characterized by water-deficit stress. In 2008 (optimum rain amount and distribution) the maximum yields were 7065 kg ha -1 (biculture) and 8112 kg ha -1 (triculture) in non irrigated conditions. The fertilization surpluses of wheat were 2853-3698 kg ha -1 (non-irrigated) and 3164-5505 kg ha -1 (irrigated) in a dry cropyear (2007) and 884-4050 kg ha -1 (non-irrigated) and 524-3990 kg ha -1 (irrigated) in an optimum cropyear (2008). The optimum fertilizer doses varied N 150-200+PK in biculture and N 50-150+PK in triculture depending on cropyear and irrigation. The optimalization of agrotechnical elements provides 7,8-8,5 t ha -1 yields in dry cropyear and 7,1-8,1 t ha -1 yields of wheat in good cropyear, respectively. Our scientific results proved that in water stress cropyear (2007) the maximum yields of maize were 4316 kg ha -1 (monoculture), 7706 kg ha -1 (biculture), 7998 kg ha -1 (triculture) in non irrigated circumstances and 8586 kg ha -1, 10 970 kg ha -1, 10 679 kg ha -1 in irrigated treatment, respectively. In dry cropyear (2007) the yield-surpluses of irrigation were 4270 kg ha -1 (mono), 3264 kg ha -1 (bi), 2681 kg ha -1 (tri), respectively. In optimum water supply cropyear (2008) the maximum yields of maize were 13 729-13 787 (mono), 14 137-14 152 kg ha -1 (bi), 13 987-14 180 kg ha -1 (tri) so there was no crop-rotation effect. We obtained 8,6-11,0 t ha -1 maximum yields of maize in water stress cropyear and 13,7-14,2 t ha -1 in optimum cropyear on chernozem soil with using appropriate agrotechnical elements.
  • Authors:
    • McNeill, A.
    • Sommer, R.
    • Ibrikci, H.
    • Ryan, J.
  • Source: Advances in Agronomy
  • Volume: 104
  • Year: 2009
  • Summary: This review examines the varied aspects of N in the soils and cropping systems as reflected by research at The International Center for Agricultural Research in the Dry Areas (ICARDA) in Syria in collaboration with other countries of the West Asia-North Africa region, especially in Morocco and other countries north and south of the Mediterranean. The synthesis, therefore, reflects a broad overview of conditions that impinge an N nutrition of crops and the evolution of N research achievements since the advent of commercial fertilization over three decades ago. With few exceptions, the soils of the Mediterranean region are low in organic matter and consequently in the reserves of total N, thus posing a limit of growing crops without fertilizer N or biological N fixation (BNF) through legumes. Soil calibration studies established the value of the soil nitrate test as a predictor of crop response with field trials to establish application rates for the main crops. Applicability is influenced by depth of sampling and the extent of mineralization. Dryland crop responses to N varied widely throughout the region from 30 to 150 kg N ha -1, being dependent on soil N status and seasonal rainfall as the major determinant of yields. Splitting the N application was only advantageous in higher rainfall areas. Residual N from BNF by food and forage legumes influenced soil N supply for cereals and relative responses to N fertilizer. The contribution of rhizobia fixation to all the major legumes was quantified using 15N along with management factors that influenced BNF by legumes. Where legumes were newly introduced to a region, rhizobial inoculation was considered necessary. With cereal responses to fertilizer N, differences between varieties were highlighted. Where urea or ammonium-N fertilizers were used, volatilization was the main loss mechanisms rather than leaching or denitrification. Considerable work was done on N use within crop rotation systems and components of the N cycle defined along with inputs from urine and feces from grazing animals. Forage legumes were shown to enhance total soil N and both labile and biomass N, with the least influence from fallow. These N forms were shown to fluctuate during the year as moisture and temperature conditions changed. Fertilizer N use had a positive effect on grain quality with increased protein, as well as soil organic matter (SOM) and thus soil quality. The significant change of the gradual introduction of supplemental irrigation in traditional rainfed cropping areas and its implications for use of models to describe the complex nature of N in dryland cropping systems was described. With the likelihood of a continuation of intensification of the dryland cropping systems in the Mediterranean region, N fertilizer use will inevitably increase and along with it the need for greater use efficiency in the interest of production economics and the environment. While limited use has been made of modeling of N, this approach is likely to be of more significance in integrating the varied facets of N under Mediterranean cropping conditions.
  • Authors:
    • Singh, V.
    • Gill, M.
  • Source: Indian Journal of Fertilisers
  • Volume: 5
  • Issue: 4
  • Year: 2009
  • Summary: The cultivated area for the last two decades is almost constant 1402 million ha and efforts are to be made to grow food grains from 230 million tonnes to 300 million tonnes by 2025. The vertical enhancement In productivity is the possible option, which has been substantiated by various research investigations. Undoubtedly, with the introduction of high yielding varieties of cereals and their continuous cultivation caused the deficiency of secondary and micronutrients in time and space, which resulted in yield stagnation. The productivity computed in terms of rice equivalent yield was highest, ranged between 8.5-12.0 tonnes/ha for rice-wheat system, 8.6 to 11.4 tonnes/ha for maize-wheat system and 5.8-7.5 tonnes ha -1 for pearl millet-wheat system under Trans Gangetic Plains amply explains about the increase in food grain production. The application of sulfur at 30-45 kg/ha enabled rice crop to fetch return per rupee invested from Rs. 11.7 to 22 while it varied from Rs. 26.4 to 35.1 under rice-wheat system. Zinc application to rice resulted to give response varying from 0.2 to 1.0 tonnes/ha in 62% of field trials out of 2154 trials. The corresponding values for wheat was 51% in 2391 field experiments. Application of S, Zn, Mn, Fe, B and at some places Mo under site specific nutrient management helped to achieve the high yield targets of 15-171 tonnes/ha per annum of rice-wheat and 14-16 tonnes/ha per annum of rice-rice cropping systems. The foliar use of micronutrients particularly Zn, Fe and Mn proved highly economical tonnes than their soil application. To enhance the food grain production, it is pertinent to delineate and map the extent and magnitude of multi-nutrient deficiencies (secondary and micronutrient) in different agro-ecological regions. Such studies are of prime Importance to check the nutritional imbalance in the food chain which will not only solve the health livelihood of the living organisms but at the same time enhance the input use efficiency, curtail the cost of production and above all enable to sustain the food security of the country by breaking the yield barrier coming on account of multi-nutrient deficiencies.
  • Authors:
    • Diaz-Zorita, M.
    • Pena-Yewtukhiw, E.
    • Grove, J.
    • Blevins, R.
  • Source: Better Crops with Plant Food
  • Volume: 93
  • Issue: 4
  • Year: 2009
  • Summary: This long-term Kentucky study evaluated the impact of tillage and N rates on crop yield and soil organic matter (SOM). After 29 years of continuous corn with a winter cereal cover crop, the combination of no-till cropping and fertilizer N use resulted in SOM levels similar to those in adjacent grass sod. There was no evidence that fertilizer N caused SOM loss.
  • Authors:
    • Matsumoto, T.
    • Taeb, M.
    • Malley, Z.
  • Source: Environment Development and Sustainability
  • Volume: 11
  • Issue: 1
  • Year: 2009
  • Summary: Sustainable agricultural development is a necessity for sustainable economic growth and social development in Africa. Sustainable agriculture largely depends on how effective natural and environmental resources are managed and utilized; it also depends on the security of continuous access to such resources. This research was aimed to look into trends in agricultural productivity, examine the persistence of the environmental insecurity, analyze the relationship between the two, and explore their links to the national development policies. The results are discussed in the context of relevance to national development policies and their implications on the sustainability of agriculture and rural livelihoods security. Literature survey, records collection from the stakeholders, village level participatory assessments (PAs), observations and questionnaire survey were tools used for data collection. The study shows significant ( P
  • Authors:
    • Cadisch, G.
    • Giller, K.
    • Kamiri, H.
    • Gathumbi, S.
    • Ndufa, J.
  • Source: Agronomy Journal
  • Volume: 101
  • Issue: 6
  • Year: 2009
  • Summary: The deliberate planting of fast-growing N 2-fixing legume monoculture species in rotation with cereal crops can be an important source of N for soil fertility replenishment. We hypothesized that mixed-species fallows have a higher potential of giving long-term residual benefits in terms of biomass, nutrients, and quality of residuals leading to long-term nutrient supply to postfallow maize ( Zea mays L.) crops. To test these hypotheses, two experiments were established in farmers' fields on very fine Kandiudalfic Eutrudox soils with monoculture and mixed-species fallows. Treatments included: sesbania [ Sesbania sesban (L.) Merr.], crotalaria ( Crotalaria grahamiana Wight and Arn.), pigeonpea [ Cajanus cajan (L.) Millsp.], siratro [ Macroptilium atropurpureum (DC.) Urb.], and calliandra ( Calliandra calothyrsus Meissn.) as monoculture-species fallow and mixture fallows of sesbania+crotalaria, sesbania+pigeonpea, sesbania+siratro, or sesbania+calliandra compared with continuous maize cropping with or without N fertilizer, and natural weed fallow. Total aboveground biomass ranged from 4.1 to 20.5 Mg ha -1 for monoculture and 7.8 to 23.3 Mg ha -1 for mixed-species fallows. Recyclable fallow biomass N ranged from 70 to 313 kg ha -1 and there was a positive interaction in some mixtures leading to increased N accumulation. Postfallow maize yields for fallows over five cropping seasons were 161-272% or 61-103% higher when compared with continuous maize without or with N fertilizer, respectively. Long-term postfallow effects on maize yield were linearly related to the amount of recycled fallow N yield. Thus, choice of fallow species to mix should be primarily driven by a better risk management strategy and an increased basket of multiple products and services.