• Authors:
    • Loon, G.
    • Hugar, L.
    • Patil, S.
    • Sarkar, A.
  • Source: Ecohealth
  • Volume: 8
  • Issue: 4
  • Year: 2011
  • Summary: In order to support agribusiness and to attain food security for ever-increasing populations, most countries in the world have embraced modern agricultural technologies. Ecological consequences of the technocentric approaches, and their sustainability and impacts on human health have, however, not received adequate attention particularly in developing countries. India is one country that has undergone a rapid transformation in the field of agriculture by adopting strategies of the Green Revolution. This article provides a comparative analysis of the effects of older and newer paradigms of agricultural practices on ecosystem and human health within the larger context of sustainability. The study was conducted in three closely situated areas where different agricultural practices were followed: (a) the head-end of a modern canal-irrigated area, (b) an adjacent dryland, and (c) an area (the ancient area) that has been provided with irrigation for some 800 years. Data were collected by in-depth interviews of individual farmers, focus-group discussions, participatory observations, and from secondary sources. The dryland, receiving limited rainfall, continues to practice diverse cropping centered to a large extent on traditional coarse cereals and uses only small amounts of chemical inputs. On the other hand, modern agriculture in the head-end emphasizes continuous cropping of rice supported by extensive and indiscriminate use of agrochemicals. Market forces have, to a significant degree, influenced the ancient area to abandon much of its early practices of organic farming and to take up aspects of modern agricultural practice. Rice cultivation in the irrigated parts has changed the local landscape and vegetation and has augmented the mosquito population, which is a potential vector for malaria, Japanese encephalitis and other diseases. Nevertheless, despite these problems, perceptions of adverse environmental effects are lowest in the heavily irrigated area.
  • Authors:
    • Diekmann, J.
    • Singh, M.
    • Masri, S.
    • Ryan, J.
    • Sommer, R.
  • Source: Soil & Tillage Research
  • Volume: 115/116
  • Year: 2011
  • Summary: Sustainability of dryland cropping is a major issue in the typical Mediterranean climatic environment of West Asia and North Africa. Management of crop residues and soil organic matter (SOM) and its interrelationship with tillage and crop rotation is of central importance for maintaining soil quality and sustaining crop yields. We examined the medium-term influence of conventional moldboard plowing compared with shallow tillage, under barley-vetch and barley-vetch-wheat-vetch rotation, with different levels of straw management (burned, removed, or incorporated) and compost addition (10 Mg ha -1 every 2 or 4 years) on the distribution with soil depth (0-30 cm) of SOM, total organic nitrogen (N tot), and labile as well as microbial carbon (C) and nitrogen (N). Shallow tillage increased SOM in 0-20 cm across all residue management treatments by on average 2.7 g kg -1. Compost addition every 2 years instead of burning or removing residues significantly increased N tot in 0-20 cm by 0.22 g kg -1, doubled labile N and C in 0-5 cm depth, and increased the ratio of labile N to N tot in 0-20 cm by 4%. Consequently, SOM accumulated in the labile pool, which reacts readily to changes in soil management practice, but which may also be depleted as quickly. Thus, shallow tillage in combination with compost addition can help build-up of SOM, and therefore soil quality. Under conditions of intensive cultivation, where crop residues are not in demand for livestock fodder, the system assessed constitutes a new agronomic direction under dryland agriculture in the Mediterranean region.
  • Authors:
    • Olson, B. L.
    • Schlegel, A. J.
    • Holman, J. D.
    • Maxwell, S. R.
  • Source: Crop Management
  • Issue: June
  • Year: 2011
  • Summary: A common crop rotation in the west-central Great Plains is no-till winter wheat-corn-fallow. Because most of the corn produced is herbicide-tolerant, volunteer corn in fallow is not controlled with glyphosate. This study evaluated the impact of volunteer corn on soil moisture storage in fallow and the succeeding winter wheat crop across three locations in western Kansas from 2008 to 2010. Volunteer corn reduced available soil water at wheat planting in 8 out of 9 site years. On average, available soil water was reduced by 1 inch for each 2,500 volunteer corn plants per acre. Volunteer corn water use reduced wheat tillers in half of the site years. Similarly, volunteer corn reduced wheat yields in half of the site years, and yields fell 1 bu/acre for every 500 volunteer corn plants per acre. When wheat yields were above 70 bu/acre or below 35 bu/acre, other factors affected wheat yield more than the preceding volunteer corn population or available soil water at wheat planting.
  • Authors:
    • Vanotti, M. B.
    • Matheny, T. A.
    • Stone, K. C.
    • Hunt, P. G.
    • Szogi, A. A.
    • Busscher, W. J.
  • Source: Communications in Soil Science and Plant Analysis
  • Volume: 42
  • Issue: 22
  • Year: 2011
  • Summary: The wastewater from swine production facilities has been typically managed by treatment in anaerobic lagoons followed by land application. However, there have been considerable advances in superior treatment technologies. Wastewater from one of these technologies was effective for subsurface drip irrigation of bermudagrass. The objectives of this experiment were to assess accumulation of soil nitrogen and carbon along with grain yield, dry-matter accumulation, and plant nitrogen accumulation of soybean [ Glycine max (L) Merr., cv.] and wheat [ Triticum aestivum (L), cv.] when supplementally irrigated with treated swine effluent via subsurface drip irrigation (SDI). The soil series was Autryville loamy sand (loamy, siliceous, subactive, thermic Arenic Paleudults). Its low unsaturated hydraulic conductivity of 0.00170.0023 mm h -1 caused problems with water movement to either the soil surface or laterally to adjoining soybean and wheat roots. This condition contributed to complete crop failure in soybean in 2 years and generally poor yields of wheat. In a good rainfall year, the soybean yield was somewhat satisfactory and benefited from the supplemental irrigation. In that year, nonirrigated and irrigated soybean mean yields were 1.55 versus 1.98 Mg ha -1, respectively. The mean yield of wheat was only 1.06 Mg ha -1, and it was not affected by irrigation. The means for soil nitrogen and carbon in the 0- to 15-cm depth were 414 and 5,679 mg kg -1, respectively, and they were not affected by the water treatments. Thus, neither soil conditions nor soybean/wheat production were greatly enhanced by the SDI system.
  • Authors:
    • Walter-Shea, E. A.
    • Singh, R. K.
    • Irmak, A.
    • Verma, S. B.
    • Suyker, A. E.
  • Source: Transactions of the American Society of Agricultural and Biological Engineers and Papers in Natural Resources. Paper 334.
  • Volume: 54
  • Issue: 1
  • Year: 2011
  • Summary: We evaluated the performance of four models for estimating soil heat flux density (G) in maize (Zea mays L.) and soybean (Glycine max L.) fields under different irrigation methods (center-pivot irrigated fields at Mead, Nebraska, and subsurface drip irrigated field at Clay Center, Nebraska) and rainfed conditions at Mead. The model estimates were compared against measurements made during growing seasons of 2003, 2004, and 2005 at Mead and during 2005, 2006, and 2007 at Clay Center. We observed a strong relationship between the G and net radiation (R n) ratio (G/R n) and the normalized difference vegetation index (NDVI). When a significant portion of the ground was bare soil, G/R n ranged from 0.15 to 0.30 and decreased with increasing NDVI. In contrast to the NDVI progression, the G/R n ratio decreased with crop growth and development. The G/R n ratio for subsurface drip irrigated crops was smaller than for the center-pivot irrigated crops. The seasonal average G was 13.1%, 15.2%, 10.9%, and 12.8% of R n for irrigated maize, rainfed maize, irrigated soybean, and rainfed soybean, respectively. Statistical analyses of the performance of the four models showed a wide range of variation in G estimation. The root mean square error (RMSE) of predictions ranged from 15 to 81.3 W m -2. Based on the wide range of RMSE, it is recommended that local calibration of the models should be carried out for remote estimation of soil heat flux.
  • Authors:
    • Lenssen, A. W.
    • Sainju, U. M.
    • Jabro, J. D.
    • Evans, R. G.
  • Source: Communications in Soil Science and Plant Analysis
  • Volume: 42
  • Issue: 18
  • Year: 2011
  • Summary: We evaluated the effect of no tillage (NT) and conventional tillage (CT) on soil penetration resistance (PR), bulk density (BD), gravimetric moisture content (MC), and saturated hydraulic conductivity (Ks) during the fallow phase of a spring wheat-fallow rotation. The study was conducted on two soils mapped as Williams loam at the Froid and Sidney sites. Soil measurements were made on 19 May, 23 June, and 4 August 2005 at the Froid site and on 6 June and 8 July 2005 at the Sidney site. Tillage had no effect on either soil properties except on the PR at Sidney. However, soil PR, MC, and BD varied significantly with depth regardless of tillage and location. Further, soil PR and MC varied with the date of sampling at both locations, and PR generally increased with decreased MC at all soil depths. Soil Ks was slightly influenced by tillage at both locations.
  • Authors:
    • Verma, S. B.
    • Vanegas, D. X.
    • Xiao, X. M.
    • Kalfas, J. L.
    • Suyker, A. E.
  • Source: Agricultural and Forest Meteorology
  • Volume: 151
  • Issue: 12
  • Year: 2011
  • Summary: Information on gross primary production (GPP) of maize croplands is needed for assessing and monitoring maize crop conditions and the carbon cycle. A number of studies have used the eddy covariance technique to measure net ecosystem exchange (NEE) of CO 2 between maize cropland fields and the atmosphere and partitioned NEE data to estimate seasonal dynamics and interannual variation of GPP in maize fields having various crop rotation systems and different water management practices. How to scale up in situ observations from flux tower sites to regional and global scales is a challenging task. In this study, the Vegetation Photosynthesis Model (VPM) and satellite images from the Moderate Resolution Imaging Spectroradiometer (MODIS) are used to estimate seasonal dynamics and interannual variation of GPP during 2001-2005 at five maize cropland sites located in Nebraska and Minnesota of the U.S.A. These sites have different crop rotation systems (continuously maize vs. maize and soybean rotated annually) and different water management practices (irrigation vs. rain-fed). The VPM is based on the concept of light absorption by chlorophyll and is driven by the Enhanced Vegetation Index (EVI) and the Land Surface Water Index (LSWI), photosynthetically active radiation (PAR), and air temperature. The seasonal dynamics of GPP predicted by the VPM agreed well with GPP estimates from eddy covariance flux tower data over the period of 2001-2005. These simulation results clearly demonstrate the potential of the VPM to scale-up GPP estimation of maize cropland, which is relevant to food, biofuel, and feedstock production, as well as food and energy security.
  • Authors:
    • Halloran, J. M.
    • Olanya, O. M.
    • Griffin, T. S.
    • Honeycutt, C. W.
    • Larkin, R. P.
    • He, Z.
  • Source: Phytopathology
  • Volume: 101
  • Issue: 1
  • Year: 2011
  • Summary: Four different potato cropping systems, designed to address specific management goals of soil conservation, soil improvement, disease suppression, and a status quo standard rotation control, were evaluated for their effects on soilborne diseases of potato and soil microbial community characteristics. The status quo system (SQ) consisted of barley under-seeded with red clover followed by potato (2-year). The soil-conserving system (SC) featured an additional year of forage grass and reduced tillage (3-year, barley/timothy-timothy-potato). The soil-improving system (SI) added yearly compost amendments to the SC rotation, and the disease-suppressive system (DS) featured diverse crops with known disease-suppressive capability (3-year, mustard/rapeseed-sudangrass/rye-potato). Each system was also compared with a continuous potato control (PP) and evaluated under both irrigated and nonirrigated conditions. Data collected over three potato seasons following full rotation cycles demonstrated that all rotations reduced stem canker (10 to 50%) relative to PP. The SQ, SC, and DS systems reduced black scurf (18 to 58%) relative to PP; ST reduced scurf under nonirri2ated but not irrigated conditions; and scurf was lower in DS than all other systems. The SQ. SC, and DS systems also reduced common scab (15 to 45%), and scab was lower in DS than all other systems. Irrigation increased black scurf and common scab but also resulted in higher yields for most rotations. SI produced the highest yields under nonirrigated conditions, and DS produced high yields and low disease under both irrigation regimes. Each cropping system resulted in distinctive changes in soil microbial community characteristics as represented by microbial populations, substrate utilization, and fatty acid methyl-ester (FAME) profiles. SI tended to increase soil moisture, microbial populations, and activity, as well result in higher proportions of monounsaturated FAMEs and the FAME biomarker for mycorrhizae (16:1 omega 6c) relative to most other rotations. DS resulted in moderate microbial populations and activity but higher substrate richness and diversity in substrate utilization profiles. DS also resulted in relatively higher proportions of FAME biomarkers for fungi (18:2 omega 6c), actinomycetes, and gram-positive bacteria than most other systems, whereas PP resulted in the lowest microbial populations and activity; substrate richness and diversity; proportions of monounsaturated and polyunsaturated FAME classes; and fungal, mycorrhizae, and actinomycete FAME biomarkers of all cropping systems. Overall, soil water, soil quality, and soilborne diseases were all important factors affecting productivity, and cropping systems addressing these constraints improved production. Cropping system approaches will need to balance these factors to achieve sustainable production and disease management.
  • Authors:
    • Galusha, T. D.
    • Jackson, D. S.
    • Mason, S. C.
    • Griess, J. K.
    • Pedersen, J. F.
    • Yaseen, M.
  • Source: Crop Science
  • Volume: 51
  • Issue: 4
  • Year: 2011
  • Summary: Grain processors would benefit from information about the production environment and the influences of the sorghum [ Sorghum bicolor (L.) Moench] hybrid on food-grade flour properties. The objective of this study was to determine the effects of environment and hybrid on rapid-visco-analysis (RVA) flour properties of commercially available food-grade sorghum. A randomized complete block experiment was planted in 12 environments, which included the 2004 and 2005 growing seasons and irrigated and dryland water regimes in eastern, central, and west central Nebraska, and a dryland, low-N environment in eastern Nebraska. The environment accounted for 71-85% of the total variation in RVA parameters, while the hybrid accounted for 11-23% and the environment-by-hybrid interaction, 1-3%. Unfortunately, the results of this experiment suggest that it is difficult to predict the effect that environment will have on resulting sorghum-flour parameters. Although of secondary importance in terms of total variation in sorghum-flour RVA properties, the choice of hybrid predictably and significantly contributes to sorghum-starch viscosity properties. Food-grade hybrids were grouped based on viscosity properties into those best suited for dry-mill and alkaline-cooked products (Asgrow Orbit; Sorghum Partners NK1486) and those best suited for porridge, consumable alcohol, and ethanol production (Kelly Green Seeds KG6902; NC+ Hybrids 7W92; Asgrow Eclipse; and Fontanelle W-1000). These results were consistent with those previously reported for grain density.
  • Authors:
    • Joshi, A. K.
    • Dixon, J.
    • Waddington, S. R.
    • Li, X.Y.
    • Vicente, M. C. de
  • Source: Food Security
  • Volume: 3
  • Issue: 1
  • Year: 2011
  • Summary: Variation in water availability is a major source of risk for agricultural productivity and food security in South Asia. Three hundred and thirty expert informants were surveyed during 2008-09 to determine the relative importance of drought and water-related constraints compared with other constraints limiting the production of four major food crops (wheat, rice, sorghum, chickpea) in five broad-based South Asian farming systems. Respondents considered drought an important constraint to crop yield in those farming systems that are predominantly rainfed, but associated it with low yield losses (well below 10% of all reported losses) for crops in farming systems with well-developed irrigation. In these systems, other water-related constraints (including difficult access to sufficient irrigation water, the high cost of irrigation, poor water management, waterlogging and flooding of low-lying fields) were more important. While confirming the importance of drought and water constraints for major food crops and farming systems in South Asia, this study also indicated they may contribute to no more than 20-30% of current yield gaps. Other types of constraint, particularly soil infertility and the poor management of fertilizer and weeds for the cereals, and pests and diseases for chickpea, contributed most yield losses in the systems. Respondents proposed a wide range of interventions to address these constraints. Continued investments in crop-based genetic solutions to alleviate drought may be justified for food crops grown in those South Asian farming systems that are predominantly rainfed. However, to provide the substantial production, sustainability and food security benefits that the region will need in coming decades, the study proposed that these be complemented by other water interventions, and by improvements to soil fertility for the cereals and plant protection with chickpea.