• Authors:
    • Muhammad. T.
    • Habib, I.
  • Source: Kasetsart Journal (Nat. Sci.)
  • Volume: 44
  • Issue: 5
  • Year: 2010
  • Summary: The alarming population growth rate in Pakistan has exacerbated the food security problem. The increase in the human population (3%) in the last two decades has nullified increased cereal production. The use of maize in the feed and wet milling industry is growing at a much larger pace than anticipated. Maize is being grown on an area of 1.016 million hectares with annual production of 3.037 million tons and an average grain yield of 2,864 kg/ha. Approximately 66% of the maize in Pakistan has access to irrigation; the remainder is farmed under strictly rain-fed conditions. Maize production in Pakistan has increased from 0.38 million tons during 1947-50 to 3.037 million tons in 2007. The trend is likely to continue at a much faster pace in the years to come. The adoption/cultivation of spring maize has increased, especially since the active involvement of multinationals in Pakistan. Today spring maize accounts for 12-15% of the total area and almost 30-35% of the total annual production. An annual increase of 20-25% in the maize area during spring has been observed, which is mainly because of very good yield levels (6-7 tons/ha). Spring maize is one of the success stories in Pakistani agriculture. Seed has been, and still is, the most important limiting factor in maize production in Pakistan. Only 34% improved seed is available. The markets are not stable and have uncertainty due to the lack of drying and grain storage facilities. The use of maize grain in poultry feed is on the increase in Punjab province up from 23% in 2001 to 55% in 2007.
  • Authors:
    • Stevens, W. E.
    • Scharf, P. C.
    • Kitchen, N. R.
    • Williams, J. D.
  • Source: Precision Agriculture
  • Volume: 11
  • Issue: 3
  • Year: 2010
  • Summary: Precise management of nitrogen (N) using canopy color in aerial imagery of corn (Zea mays L.) has been proposed as a strategy on which to base the rate of N fertilizer. The objective of this study was to evaluate the relationship between canopy color and yield response to N at the field scale. Six N response trials were conducted in 2000 and 2001 in fields with alluvial, claypan and deep loess soil types. Aerial images were taken with a 35-mm slide film from C1100 m at the mid- and late-vegetative corn growth stages and processed to extract green and red digital values. Color values of the control N (0 kg N ha-1) and sufficient N (280 kg N ha-1 applied at planting) treatments were used to calculate the relative ratio of unfertilized to fertilized and relative difference color values. Other N fertilizer treatments included side-dressed applications in increments of 56 kg N ha-1. The economic optimal N rate was weakly related (R2<= 0.34) or not related to the color indices at both growth stages. For many sites, delta yield (the increase in yield between control N and sufficient N treatments) was related to the color indices (R2<= 0.67) at the late vegetative growth stage; the best relationship was with green relative difference. The results indicate the potential for color indices from aerial photographs to be used for predicting delta yield from which a site-specific N rate could be determined.
  • Authors:
    • Franti, T. G.
    • Drijber, R. A.
    • Wortmann, C. S.
  • Source: Agronomy Journal
  • Volume: 102
  • Issue: 4
  • Year: 2010
  • Summary: Continuous no-till (NT) can be beneficial relative to tillage with fewer field operations, reduced erosion, and surface soil improvement. Field research was conducted at two locations for 5 yr in eastern Nebraska to test the hypotheses that one-time tillage of NT can result in increased grain yield, reduced stratification of soil properties persisting for at least 5 yr, a net gain in soil organic carbon (SOC), and a restoration of the soil microbial community to NT composition. Stratification of soil test P, SOC, and bulk density was similar for all tillage treatments at 5 yr after tillage. Water stable soil aggregates (WSA) were not affected by tillage treatments except that there was more soil as macroaggregates at one location in the 5- to 10-cm depth with moldboard plow tillage (MP) compared with NT. Tillage treatments had no effect on SOC mass in the 0- to 30-cm depth. Soil microbial biomass was greater at the 0- to 5-cm compared with the 5- to 10-cm depth. Biomass of bacteria, actinomycetes, and arbuscular mycorrhizal fungi was greater with NT compared with one-time MP at one location but not affected by the one-time tillage at the other location. Microbial community structure differed among tillage treatments at the 0- to 5-cm depth at one location but not at the other location. Grain yield generally was not affected by tillage treatment. One-time tillage of NT can be done without measureable effects on yield or soil properties.
  • Authors:
    • Robertson, G. P.
    • Grace, P. R.
    • Bohm, S.
    • McSwiney, C. P.
  • Source: Journal of Natural Resources & Life Sciences Education
  • Volume: 39
  • Year: 2010
  • Summary: Opportunities for farmers to participate in greenhouse gas (GHG) credit markets require that growers, students, extension educators, offset aggregators, and other stakeholders understand the impact of agricultural practices on GHG emissions. The Farming Systems Greenhouse Gas Emissions Calculator, a web-based tool linked to the SOCRATES soil carbon process model, provides a simple introduction to the concepts and magnitudes of gas emissions associated with crop management. Users choose a county of interest on an introductory screen and are taken to the input/output window, where they choose crops, yields, tillage practices, or nitrogen fertilizer rates. Default values are provided based on convention and county averages. Outputs include major contributors of greenhouse gases in field crops: soil carbon change, nitrous oxide (N2O) emission, fuel use, and fertilizer. We contrast conventional tillage and no-till in a corn-soybean-wheat (Zea mays L. Glycine max (L.) Merr. Triticum aestivum L.) rotation and compare continuous corn fertilized at 101 and 134 kg N ha -1 yr -1. In corn years, N2O was the dominant GHG, due to high fertilizer requirements for corn. No-till management reduced greenhouse gas emissions by 50% due to net soil carbon storage. Continuous corn fertilized at 101 kg N ha-1 yr-1 emitted 1.25 Mg CO2 equivalents ha-1 yr-1 compared with 1.42 Mg CO2 equivalents ha-1 yr-1 at 134 kg N ha-1 yr-1, providing a 12% GHG savings. The calculator demonstrates how cropping systems and management choices affect greenhouse gas emissions in field crops.
  • Authors:
    • Anderson, R. L.
  • Source: Renewable Agriculture and Food Systems
  • Volume: 25
  • Issue: 3
  • Year: 2010
  • Summary: Weeds are a major obstacle to successful crop production in organic farming. Producers may be able to reduce inputs for weed management by designing rotations to disrupt population dynamics of weeds. Population-based management in conventional farming has reduced herbicide use by 50% because weed density declines in cropland across time. In this paper, we suggest a 9-year rotation comprised of perennial forages and annual crops that will disrupt weed population growth and reduce weed density in organic systems. Lower weed density will also improve effectiveness of weed control tactics used for an individual crop. The rotation includes 3-year intervals of no-till, which will improve both weed population management and soil health. Even though this rotation has not been field tested, it provides an example of designing rotations to disrupt population dynamics of weeds. Also, producers may gain additional benefits of higher crop yield and increased nitrogen supply with this rotation design.
  • Authors:
    • Dejoux, J. F.
    • Aubinet, M.
    • Bernhofer, C.
    • Bodson, B.
    • Buchmann, N.
    • Carrara, A.
    • Cellier, P.
    • Di Tommasi, P.
    • Elbers, J. A.
    • Eugster, W.
    • Gruenwald, T.
    • Jacobs, C. M. J.
    • Jans, W. W. P.
    • Jones, M.
    • Kutsch, W.
    • Lanigan, G.
    • Magliulo, E.
    • Marloie, O.
    • Moors, E. J.
    • Moureaux, C.
    • Olioso, A.
    • Osborne, B.
    • Sanz, M. J.
    • Saunders, M.
    • Smith, P.
    • Soegaard, H.
    • Wattenbach, M.
    • Ceschia, E.
    • Beziat, P.
  • Source: Agriculture, Ecosystems & Environment
  • Volume: 139
  • Issue: 3
  • Year: 2010
  • Summary: The greenhouse gas budgets of 15 European crop sites covering a large climatic gradient and corresponding to 41 site-years were estimated. The sites included a wide range of management practices (organic and/or mineral fertilisation, tillage or ploughing, with or without straw removal, with or without irrigation, etc.) and were cultivated with 15 representative crop species common to Europe. At all sites, carbon inputs (organic fertilisation and seeds), carbon exports (harvest or fire) and net ecosystem production (NEP), measured with the eddy covariance technique, were calculated. The variability of the different terms and their relative contributions to the net ecosystem carbon budget (NECB) were analysed for all site-years, and the effect of management on NECB was assessed. To account for greenhouse gas (GHG) fluxes that were not directly measured on site, we estimated the emissions caused by field operations (EFO) for each site using emission factors from the literature. The EFO were added to the NECB to calculate the total GHG budget (GHGB) for a range of cropping systems and management regimes. N2O emissions were calculated following the IPCC (2007) guidelines, and CH4 emissions were estimated from the literature for the rice crop site only. At the other sites, CH4 emissions/oxidation were assumed to be negligible compared to other contributions to the net GHGB. Finally, we evaluated crop efficiencies (CE) in relation to global warming potential as the ratio of C exported from the field (yield) to the total GHGB. On average, NEP was negative (-284 +/- 228 gC m(-2) year(-1)), and most cropping systems behaved as atmospheric sinks, with sink strength generally increasing with the number of days of active vegetation. The NECB was, on average, 138 +/- 239 gC m(-2) year(-1), corresponding to an annual loss of about 2.6 +/- 4.5% of the soil organic C content, but with high uncertainty. Management strongly influenced the NECB, with organic fertilisation tending to lower the ecosystem carbon budget. On average, emissions caused by fertilisers (manufacturing, packaging, transport, storage and associated N2O emissions) represented close to 76% of EFO. The operation of machinery (use and maintenance) and the use of pesticides represented 9.7 and 1.6% of EFO, respectively. On average, the NEP (through uptake of CO2) represented 88% of the negative radiative forcing, and exported C represented 88% of the positive radiative forcing of a mean total GHGB of 203 +/- 253 gC-eq m(-2) year(-1). Finally, CE differed considerably among crops and according to management practices within a single crop. Because the CE was highly variable, it is not suitable at this stage for use as an emission factor for management recommendations, and more studies are needed to assess the effects of management on crop efficiency.
  • Authors:
    • Yu Qiang
    • Wang Enli
    • Chen Chao
  • Source: Agricultural Water Management
  • Volume: 97
  • Issue: 8
  • Year: 2010
  • Summary: In the North China Plain (NCP), while irrigation using groundwater has maintained a high-level crop productivity of the wheat-maize double cropping systems, it has resulted in rapid depletion of groundwater table. For more efficient and sustainable utilization of the limited water resources, improved understanding of how crop productivity and water balance components respond to climate variations and irrigation is essential. This paper investigates such responses using a modelling approach. The farming systems model APSIM (Agricultural Production Systems Simulator) was first calibrated and validated using 3 years of experimental data. The validated model was then applied to simulate crop yield and field water balance of the wheat-maize rotation in the NCP. Simulated dryland crop yield ranged from 0 to 4.5 t ha -1 for wheat and 0 to 5.0 t ha -1 for maize. Increasing irrigation amount led to increased crop yield, but irrigation required to obtain maximum water productivity (WP) was much less than that required to obtain maximum crop yield. To meet crop water demand, a wide range of irrigation water supply would be needed due to the inter-annual climate variations. The range was simulated to be 140-420 mm for wheat, and 0-170 mm for maize. Such levels of irrigation applications could potentially lead to about 1.5 m year -1 decline in groundwater table when other sources of groundwater recharge were not considered. To achieve maximum WP, one, two and three irrigations (i.e., 70, 150 and 200 mm season -1) were recommended for wheat in wet, medium and dry seasons, respectively. For maize, one irrigation and two irrigations (i.e., 60 and 110 mm season -1) were recommended in medium and dry seasons, while no irrigation was needed in wet season.
  • Authors:
    • Snapp, S. S.
    • Robertson, G. P.
    • Gelfand, I.
  • Source: Environmental Science & Technology
  • Volume: 44
  • Issue: 10
  • Year: 2010
  • Summary: The prospect of biofuel production on a large scale has focused attention on energy efficiencies associated with different agricultural systems and production goals. We used 17 years of detailed data on agricultural practices and yields to calculate an energy balance for different cropping systems under both food and fuel scenarios. We compared four grain and one forage systems in the U.S. Midwest: corn ( Zea mays) - soybean ( Glycine max) - wheat ( Triticum aestivum) rotations managed with (1) conventional tillage, (2) no till, (3) low chemical input, and (4) biologically based (organic) practices, and (5) continuous alfalfa ( Medicago sativa). We compared energy balances under two scenarios: all harvestable biomass used for food versus all harvestable biomass used for biofuel production. Among the annual grain crops, average energy costs of farming for the different systems ranged from 4.8 GJ ha -1 y -1 for the organic system to 7.1 GJ ha -1 y -1 for the conventional; the no-till system was also low at 4.9 GJ ha -1 y -1 and the low-chemical input system intermediate (5.2 GJ ha -1 y -1). For each system, the average energy output for food was always greater than that for fuel. Overall energy efficiencies ranged from output:input ratios of 10 to 16 for conventional and no-till food production and from 7 to 11 for conventional and no-till fuel production, respectively. Alfalfa for fuel production had an efficiency similar to that of no-till grain production for fuel. Our analysis points to a more energetically efficient use of cropland for food than for fuel production and large differences in efficiencies attributable to management, which suggests multiple opportunities for improvement.
  • Authors:
    • Ghosh, P. K.
    • Das, A.
    • Saha, R.
    • Kharkrang, E.
    • Tripathi, A. K.
    • Munda, G. C.
    • Ngachan, S. V.
  • Source: Current Science
  • Volume: 99
  • Issue: 7
  • Year: 2010
  • Summary: Productivity of rainfed monocropping farming system in North Eastern Region of India is low and it is a high economic risk activity. Intensive natural resources mining, continuous degradation of natural resources (soil, water, vegetation) and practice of monocropping under conventional agricultural practices will not ensure farm productivity and food security in the coming years. In order to keep the production system in different land situations sustainable, conservation agriculture based on no-till system is an alternative to reconcile agriculture with its environment and overcome the imposed constraints of climate change and continuous inputs cost. Studies on conservation tillage and residue management in different land situations were conducted during 2006-2009 and they are highlighted in this article. In terrace upland, growing mustard completely on residual moisture following upland rice/maize was possible when it is practised under conservation tillage (crop residue of all crops, including weed biomass incorporated). Similarly, in valley upland, growing second crop of pea in rice fallow is possible if two-thirds or half of rice residues are retained on the soil surface under zero tillage. A long-term study (2006-2009) revealed that double no-till practice in rice-based system is cost-effective, restored soil organic carbon (70.75%), favoured biological activity (46.7%), conserved water and produced yield (49%) higher than conventional tillage. Therefore, conservation tillage practised in terrace upland, valley upland and low-land situations ensured double-cropping, improved farm income and livelihood in rainfed NE India.
  • Authors:
    • Halvorson, A. D.
    • Grosso, S. J. del
    • Alluvione, F.
  • Source: Soil Science Society of America Journal
  • Volume: 74
  • Issue: 2
  • Year: 2010
  • Summary: Nitrogen fertilization is essential for optimizing crop yields; however, it increases N 2O emissions. The study objective was to compare N 2O emissions resulting from application of commercially available enhanced-efficiency N fertilizers with emissions from conventional dry granular urea in irrigated cropping systems. Nitrous oxide emissions were monitored from corn ( Zea mays L.) based rotations receiving fertilizer rates of 246 kg N ha -1 when in corn, 56 kg N ha -1 when in dry bean ( Phaseolus vulgaris L.), and 157 kg N ha -1 when in barley ( Hordeum vulgare L. ssp. vulgare). Cropping systems included conventional-till continuous corn (CT-CC), no-till continuous corn (NT-CC), no-till corn-dry bean (NT-CDb), and no-till corn-barley (NT-CB). In the NT-CC and CT-CC systems, a controlled-release, polymer-coated urea (ESN) and dry granular urea were compared. In the NT-CDb and NT-CB rotations, a stabilized urea source (SuperU) was compared with urea. Nitrous oxide fluxes were measured during two growing seasons using static, vented chambers and a gas chromatograph analyzer. Cumulative growing season N 2O emissions from urea and ESN application were not different under CT-CC, but ESN reduced N 2O emissions 49% compared with urea under NT-CC. Compared with urea, SuperU reduced N 2O emissions by 27% in dry bean and 54% in corn in the NT-CDb rotation and by 19% in barley and 51% in corn in the NT-CB rotation. This work shows that the use of no-till and enhanced-efficiency N fertilizers can potentially reduce N 2O emissions from irrigated systems.