• Authors:
    • Delgado, J. A.
    • Bausch, W.
  • Source: Precision Agriculture
  • Volume: 6
  • Issue: 6
  • Year: 2005
  • Summary: Spatial and temporal variability of soil nitrogen (N) supply together with temporal variability of plant N demand make conventional N management difficult. This study was conducted to determine the impact of residual soil nitrate-N (NO3-N) on ground-based remote sensing management of in-season N fertilizer applications for commercial center-pivot irrigated corn (Zea mays L.) in northeast Colorado. Wedge-shaped areas were established to facilitate fertigation with the center pivot in two areas of the field that had significantly different amounts of residual soil NO3-N in the soil profile. One in-season fertigation (48 kg N ha-1) was required in the Bijou loamy sand soil with high residual NO3-N versus three in-season fertigations totaling 102 kg N ha-1 in the Valentine fine sand soil with low residual NO3-N. The farmer applied five fertigations to the field between the wedges for a total in-season N application of 214 kg N ha-1. Nitrogen input was reduced by 78% and 52%, respectively, in these two areas compared to the farmer's traditional practice without any reductions in corn yield. The ground-based remote sensing management of in-season applied N increased N use efficiency and significantly reduced residual soil NO3-N (0-1.5 m depth) in the loamy sand soil area. Applying fertilizer N as needed by the crop and where needed in a field may reduce N inputs compared to traditional farmer accepted practices and improve in-season N management.
  • Authors:
    • Parandiyal, A.
    • Singh, S.
    • Arjun, P.
    • Singh, K.
    • Ashok, K.
    • Shakir, A.
    • Prasad, S.
    • Singh, R.
  • Source: Indian Journal of Soil Conservation
  • Volume: 33
  • Issue: 2
  • Year: 2005
  • Summary: Bunding and field levelling are the most preferred activities in the community-driven watershed projects in the semiarid region. In a two-year study carried out during June 1999 to June 2001 on a farmer's field in a ravinous watershed located in south-eastern Rajasthan, India, the effect of bunding and levelling on in situ moisture conservation and corresponding increase in grain and stover yields of chickpea, mustard, sorghum and soyabean was compared. These land treatments considerably improved profile moisture and crop yields during normal as well as deficit monsoon year. Results indicated that conservation measures can potentially stabilize crop production under dryland cropping systems. The land treatments and choice of crops were significant factors influencing economic productivity of land uses. In response to bunding alone and bunding with levelling, crop production increased by 46 and 112%, respectively, over control. Mustard cultivation recovered 76% of the bunding cost and 64% of the bunding+levelling cost in the first year only after imposing land treatments. It is concluded that in semiarid regions, appropriate conservation measures coupled with suitable land use planning result in convincing tangible benefits on short-terms basis, apart from their protective and long-term intangible benefits.
  • Authors:
    • Álvaro-Fuentes, J.
    • Arrúe, J. L.
    • López, M. V.
    • Moret, D.
  • Source: European Journal of Agronomy
  • Volume: 23
  • Issue: 1
  • Year: 2005
  • Summary: Most of the benefits from conservation tillage are attained by maintaining crop residues on the soil surface. However, the effectiveness of crop residues depends on their persistence in time and maintenance of sufficient residue cover can become difficult, especially when a long-fallow period is involved. In this study, we evaluate the effects of conventional tillage (CT) and two conservation tillage systems (reduced tillage, RT, and no-tillage, NT), under both continuous cropping (CC) and cereal-fallow rotation (CF), on the dynamics of surface barley residues during four fallow periods in a dryland field of semiarid Aragon. The CC system involves a summer fallow period of 5-6 months and the CF rotation a long-fallow of 17-18 months. Results indicate that the lack of residue-disturbing operations in NT makes this practice the best strategy for fallow management. With this tillage system, the soil surface still conserved a residue cover of 10-15% after long-fallowing and percentages of standing residues ranging from 20 to 40% of the total mass after the first 11-12 months. In both CT and RT, primary tillage operations had the major influence on residue incorporation, with percentages of cover reduction of 90-100% after mouldboard ploughing (CT) and 50-70% after chiselling (RT). Two decomposition models were tested, the Douglas-Rickman and the Steiner models. Our data indicate that the Steiner model described more accurately the decline of surface residue mass over the long-fallow period in the NT plots. Measured and predicted data indicate that, under NT, 80-90% of the initial residue mass is lost at the end of fallow and that 60-75% of this loss occurs during the first 9-10 months. Finally, the mass-to-cover relationship established in this study for barley residues could be used to predict soil cover from flat residue mass through the fallow period by using a single A(m) coefficient (0.00208 ha kg(-1)). (C) 2004 Elsevier B.V. All rights reserved.
  • Authors:
    • Mundra, M. C.
    • Singh, B. P.
    • Gupta, S. C.
  • Source: Research on Crops
  • Volume: 6
  • Issue: 2
  • Year: 2005
  • Summary: A field experiment was conducted at Chaudhary Charan Singh Haryana Agricultural University, Hisar, India, for three consecutive years (2000/01-2002/03) to determine the efficient cropping system for irrigated conditions of southwest Haryana. Among the cropping systems evaluated, pearl millet (cv. HHB-67)-potato (cv. Kufri Bahar)-green gram (cv. MH 85-111) was identified as the most efficient system, showing the highest total equivalent yield (14344 kg/ha), gross return (Rs. 93 910/ha), net return (Rs. 47 965/ha), energy equivalent (50585 Kcal * 1000/ha) and system productivity (55.17). The highest land use efficiency (93.15) and risk factor (Rs. 7898/ha) were found in soyabean (cv. PK 472)-wheat (cv. PBW343)-cowpea fodder cropping system. The maximum benefit:cost ratio (2.48) and system index (0.85) were recorded in sorghum fodder (cv. HC-71)-wheat. Positive nutrient balance of 607.7 kg/ha was recorded only in the pearl millet-potato-green gram cropping system, and it was negative in all other systems though it was minimum in cotton-wheat and pearl millet-wheat. There was no change in the pH, electrical conductivity and organic carbon content in the soil. Available N decreased in soyabean-wheat-cowpea (F) and pearlmillet-fieldpea-maize (F). Available P also decreased in the pearl millet-fieldpea-maize (F) and pearl millet-potato-green gram. The decrease in K content was relatively higher in the pearl millet-wheat, soyabean-wheat-cowpea (F) and cotton-wheat cropping systems as compared to initial soil fertility status.
  • Authors:
    • Harveson, R. M.
    • Burgener, P. A.
    • Blumenthal, J. M.
    • Baltensperger, D. D.
    • Lyon, D. J.
  • Source: Crop Science
  • Volume: 44
  • Issue: 3
  • Year: 2004
  • Summary: ummer fallow is commonly used to stabilize winter wheat (Triticum aestivum L.) production in the Central Great Plains, but summer fallow results in soil degradation, limits farm productivity and profitability, and stores soil water inefficiently. The objectives of this study were to quantify the production and economic consequences of replacing summer fallow with spring-planted crops on the subsequent winter wheat crop. A summer fallow treatment and five spring crop treatments [spring canola (Brassica napus L.), oat (Avena sativa L.) + pea (Pisum sativum L.) for forage, proso millet (Panicum miliaceum L.), dry bean (Phaseolus vulgaris L.), and corn (Zea mays L.)] were no-till seeded into sunflower (Helianthus annuus L.) residue in a randomized complete block design with five replications during 1999, 2000, and 2001. Winter wheat was planted in the fall following the spring crops. Five N fertilizer treatments (0, 22, 45, 67, and 90 kg N ha-1) were randomly assigned to each previous spring crop treatment in a split-plot treatment arrangement. The 3-yr mean wheat grain yield after summer fallow was 29% greater than following oat + pea for forage and 86% greater than following corn. The 3-yr mean annualized net return for the spring crop and subsequent winter wheat crop was $4.20, -$6.91, -$7.55, -$29.66, -$81.17, and -$94.88 ha-1 for oat + pea for forage, proso millet, summer fallow, dry bean, corn, and spring canola, respectively. Systems involving oat + pea for forage and proso millet are economically competitive with systems using summer fallow.
  • Authors:
    • Shi, Y.
    • Jjemba, P. K.
    • Song, Q.
    • Li, F.
  • Source: Soil Biology and Biochemistry
  • Volume: 36
  • Issue: 11
  • Year: 2004
  • Summary: Microbial biomass C (MBC) is one of the soil properties used as an indicator for the fertility status of a soil. A study was conducted on a semi-arid Loess Plateau in China. The field was planted with spring wheat and mulched with plastic film for various lengths of time. Our primary objectives were to (i) explore the influence of film mulching on soil MBC and soil fertility, and (ii) seek an effective approach of maintaining and improving sustainability of cropland mulched with plastic film in two growing seasons. Four treatments were tested, non-mulching (M0), mulching for 30 days after sowing (M30), mulching for 60 DAS (M60) and mulching for the whole growing period (Mw). An increasing air temperature with time within the growing season promoted soil MBC in the two growing seasons, but a severe drought led to a lower MBC in 2000 compared with the wet year of 1999. Film mulching promoted MBC significantly in the 2 years, but decreased soil organic carbon (SOC). SOC is very low in the experimental soil, accounting for the higher MBC/SOC ratio compared with ratios reported by others. The SOC is greatly reduced in the non-mulched and the Mw treatments compared to the M30 and M60 treatments. In conclusion, the benefits of film mulching in semi-arid agricultural systems are enormous but realizing their full potential depends on how long the mulching material is maintained during the growing season. In the system tested, it is desirable to mulch the plots for 30–60 DAS in order to enhance microbial biomass and cycling of nutrients and also to provide a more stable soil micro-environment that generates more residues in the rhizosphere.
  • Authors:
    • Arshad, M. A.
    • Franzluebbers, A. J.
    • Azooz, R. H.
  • Source: Soil & Tillage Research
  • Volume: 77
  • Issue: 1
  • Year: 2004
  • Summary: Conservation tillage has become a major soil management strategy to reduce soil erosion and improve soil quality, yet the impacts of crop rotation on soil responses to conservation tillage remain poorly described. We investigated the effects of (i) perennial grass cover versus annual cropping and (ii) type of break crop in a wheat (Triticum aestivum L.)-based crop rotation system on surface-soil (0-10 cm) structural and organic matter properties towards the end of a decade of continuous management on an Albic Luvisol in the cold, semiarid region of northwestern Canada. Soil aggregation was at state to resist water erosion more under perennial grass (i.e. bromegrass (Bromus inermis Leyss.) and red fescue (Festuca rubra L.)) than under annual cropping systems (mean-weight diameter of 2.1 and 1.6 mm under perennial and annual systems, respectively). Soil organic C was higher (44 g C kg-1 soil versus 38 g C kg-1 soil), but total soil N was lower (3.5 g N kg-1 soil versus 3.9 g N kg-1 soil) under perennial compared with annual cropping systems. There were few significant differences in soil-structural properties among the various annual cropping systems. The largest effect was greater light-fraction C and N under continuous wheat (4.0 g C kg-1 soil and 0.27 g N kg-1 soil) compared with other rotations, especially wheat-wheat-fallow (2.4 g C kg-1 soil and 0.16 g N kg-1 soil), as a result of higher residue inputs. Relationships between mean-weight diameter of water-stable aggregates and biochemical properties were strongest for soil microbial biomass C and soil organic C. Perennial grass cover exhibited greater potential to preserve soil-structural properties than no-tillage annual cropping.
  • Authors:
    • Iraj Eskandari
    • Abbas Hemmat
  • Source: Aktualni zadaci mehanizacije poljoprivrede. Zbornik radova, 31. međunarodnog simpozija iz područja mehanizacije poljoprivrede, Opatija, Hrvatska, 24-28 veljač 2003
  • Year: 2003
  • Authors:
    • Yang, H.
    • Walters, D. T.
    • Dobermann, A.
    • Cassman, K. G.
  • Source: Annual Review of Environment and Resources
  • Volume: 28
  • Issue: 1
  • Year: 2003
  • Summary: Agriculture is a resource-intensive enterprise. The manner in which food production systems utilize resources has a large influence on environmental quality. To evaluate prospects for conserving natural resources while meeting increased demand for cereals, we interpret recent trends and future trajectories in crop yields, land and nitrogen fertilizer use, carbon sequestration, and greenhouse gas emissions to identify key issues and challenges. Based on this assessment, we conclude that avoiding expansion of cultivation into natural ecosystems, increased nitrogen use efficiency, and improved soil quality are pivotal components of a sustainable agriculture that meets human needs and protects natural resources. To achieve this outcome will depend on raising the yield potential and closing existing yield gaps of the major cereal crops to avoid yield stagnation in some of the world's most productive systems. Recent trends suggest, however, that increasing crop yield potential is a formidable scientific challenge that has proven to be an elusive goal.
  • Authors:
    • Blumenthal, J. M.
    • McLean, G. B.
    • Hammer, G. L.
    • Lyon, D. J.
  • Source: Agronomy Journal
  • Volume: 95
  • Issue: 4
  • Year: 2003
  • Summary: In a 2-yr multiple-site field study conducted in western Nebraska during 1999 and 2000, optimum dryland corn ( Zea mays L.) population varied from less than 1.7 to more than 5.6 plants m -2, depending largely on available water resources. The objective of this study was to use a modelling approach to investigate corn population recommendations for a wide range of seasonal variation. A corn growth simulation model (APSIM-maize) was coupled to long-term sequences of historical climatic data from western Nebraska to provide probabilistic estimates of dryland yield for a range of corn populations. Simulated populations ranged from 2 to 5 plants m -2. Simulations began with one of three levels of available soil water at planting, either 80, 160, or 240 mm in the surface 1.5 m of a loam soil. Gross margins were maximized at 3 plants m -2 when starting available water was 160 or 240 mm, and the expected probability of a financial loss at this population was reduced from about 10% at 160 mm to 0% at 240 mm. When starting available water was 80 mm, average gross margins were less than $15 ha -1, and risk of financial loss exceeded 40%. Median yields were greatest when starting available soil water was 240 mm. However, perhaps the greater benefit of additional soil water at planting was reduction in the risk of making a financial loss. Dryland corn growers in western Nebraska are advised to use a population of 3 plants m -2 as a base recommendation.