• Authors:
    • Leytem, A. B.
    • Venterea, R. T.
    • Fixen, P. E.
    • Snyder, C. S.
    • Liebig, M. A.
    • Del Grosso, S. J.
    • Cavigelli, M. A.
    • McLain, J. E.
    • Watts, D. B.
  • Source: Frontiers in Ecology and the Environment
  • Volume: 10
  • Issue: 10
  • Year: 2012
  • Summary: The use of commercial nitrogen (N) fertilizers has led to enormous increases in US agricultural productivity. However, N losses from agricultural systems have resulted in numerous deleterious environmental impacts, including a continuing increase in atmospheric nitrous oxide (N2O), a greenhouse gas (GHG) and an important catalyst of stratospheric ozone depletion. Although associated with about 7% of total US GHG emissions, agricultural systems account for 75% of total US N2O emissions. Increased productivity in the crop and livestock sectors during the past 30 to 70 years has resulted in decreased N2O emissions per unit of production, but N2O emissions from US agriculture continue to increase at a rate of approximately 0.46 teragrams of carbon dioxide equivalents per year (2002-2009). This rate is lower than that during the late 20th century. Improvements in agricultural productivity alone may be insufficient to lead to reduced emissions; implementing strategies specifically targeted at reducing N2O emissions may therefore be necessary. Front Ecol Environ 2012; 10(10): 537-546, doi:10.1890/120054
  • Authors:
    • Chase, C.
    • Cwach, D.
    • Delate, K.
  • Source: Renewable Agriculture and Food Systems
  • Volume: 27
  • Issue: 1
  • Year: 2012
  • Summary: Novel technologies to reduce tillage in organic systems include a no-tillage roller/crimper for terminating cover crops prior to commercial crop planting. The objective of this experiment was to compare: (1) weed management and yield effects of organic tilled and no-tillage systems for corn ( Zea mays L.), soybean [ Glycine max (L.) Merr.] and irrigated tomato ( Lycopersicon esculentum Mill.), using a roller/crimper and two cover crop combinations [hairy vetch/rye ( Vicia villosa Roth/ Secale cereale L.) and winter wheat/Austrian winter pea ( Triticum vulgare L./ Pisum sativum L. ssp. arvense (L.) Poir.)]; and (2) the economic performance of each system. Weed management ranged from fair to excellent in the organic no-tillage system for soybean and tomato crops, with the rye/hairy vetch mulch generally providing the most weed suppression. Corn suffered from low rainfall, competition from weeds and hairy vetch re-growth and, potentially, low soil nitrogen (N) from lack of supplemental fertilization and N immobilization during cover crop decomposition. No-tillage corn yields averaged 5618 and 634 kg ha -1 in 2006 and 2007, respectively, which was 42-92% lower than tilled corn. No-tillage soybeans in 2007 averaged 2793 kg ha -1 compared to 3170 kg ha -1 for tilled soybeans, although no-tillage yields were 48% of tilled yields in the dry year of 2006. Irrigated tomato yields averaged 40 t ha -1 in 2006 and 63 t ha -1 in 2007, with no statistical differences among tillage treatments. Economic analysis for the three crops revealed additional cover crop seed and management costs in the no-tillage system. Average organic corn returns to management were US$1028 and US$2466 ha -1 greater in the tilled system compared to the no-tillage system in 2006 and 2007, respectively, which resulted mainly from the dramatically lower no-tillage yields. No-tillage soybean returns to management were negative in 2006, averaging US$ -14 ha -1, compared to US$742 ha -1 for tilled soybeans. However, in 2007, no-tillage soybean returns averaged US$1096 ha -1. The 2007 no-tillage irrigated tomato returns to management averaged US$53,515 compared to US$55,515 in the tilled system. Overall, the organic no-tillage soybean and irrigated tomato system demonstrated some promise for reducing tillage in organic systems, but until economic benefits from soil carbon enhancement can be included for no-tillage systems, soil improvements probably cannot offset the economic losses in no-tillage systems. Irrigation could improve the performance of the no-tillage system in dry years, especially if grain crops are rotated with a high-value irrigated tomato crop.
  • Authors:
    • Wise, J. C.
    • van Timmeren, S.
    • Isaacs, R.
  • Source: Pest Management Science
  • Volume: 68
  • Issue: 4
  • Year: 2012
  • Summary: BACKGROUND: Soil application of systemic neonicotinoid insecticides can provide opportunities for long-term control of insect pests in vineyards, with minimal risk of pesticide drift or worker exposure. This study compared the effectiveness of neonicotinoid insecticides applied via irrigation injection on key early-season and mid-season insect pests of vineyards in the eastern United States. RESULTS: On vines trained to grow on drip irrigation, early-season application of imidacloprid, clothianidin, thiamethoxam and dinotefuran provided high levels of control against the potato leafhopper, Empoasca fabae. Protection of vines against Japanese beetle, Popillia japonica, and grape berry moth, Paralobesia viteana, was also observed after mid-season applications. Efficacy was poor in commercial vineyards when treatments were applied to the soil before irrigation or rain, indicating that vines must be grown with an irrigation system for efficient uptake of the insecticide. CONCLUSIONS: In drip-irrigated vineyards, soil-applied neonicotinoids can be used to provide long residual control of either early-season or mid- to late-season foliage pests of vineyards. This approach can reduce the dependence on foliar-applied insecticides, with associated benefits for non-target exposure to workers and natural enemies.
  • Authors:
    • Zhang, Z
    • Sui, X.
    • Wang, S.
    • Zhang, L.
    • Gao, L.
    • Zhang, L.
  • Source: Scientia Horticulturae
  • Volume: 138
  • Year: 2012
  • Summary: Water and nitrogen in soil have a great effect on growth and productivity of cucumber (Cucumis sativus L.), which is widely cultivated with high economic benefit in solar greenhouse in North China. To understand the effects of alternate furrow irrigation (AFI) and nitrogen levels on migration of water and nitrogen in soil, accumulation of nitrate-nitrogen (NO3--N) and root growth of cucumber in the solar greenhouse, cucumber variety Jinyu No. 5 was fertilized with different amounts of nitrogen [no nitrogen (CK2), optimal nitrogen (AINo), conventional nitrogen (AINc)] under AFI. Conventional furrow irrigation and conventional nitrogen were used as the control (CK1). The results indicated that soil NO3--N content, electrical conductivity values in the 0-20 cm, 20-40 cm and 40-60 cm layers, and soil residual NO3--N content at the end of the two growing seasons were all increased as the nitrogen fertilizer increased under AFI, especially in the top layer of soil (0-20 cm). However, compared with conventional furrow irrigation, AFI with optimized fertilizer led to increases of root length, root biomass yield, root-shoot ratio of the cucumber crop and economic coefficient (K). AFI also greatly improved both biomass and economic yield water use efficiency. Altogether, AFI with optimized fertilizer (AINo) was a good irrigation practice in the solar greenhouse for increasing the use efficiency of both water and fertilizer, reducing salinity accumulation in the top soil, and maintaining economic yield of cucumber crop. (C) 2012 Elsevier B.V. All rights reserved.
  • Authors:
    • Luo,Y.
    • Zhou,C.
  • Source: Journal of Food, Agriculture and Environment
  • Volume: 10
  • Issue: 2
  • Year: 2012
  • Summary: Panzhuang Irrigation District is one of the Yellow River irrigation areas. The spatial and temporal distribution of water resources is severely uneven in the upper, middle and lower reaches of the irrigation district. In order to solve this problem, it is necessary to study the differences of crop water consumption (evapotranspiration-ET), irrigation amount, soil water and water use efficiency (WUE) of winter wheat, summer maize and cotton which are the main crops in the irrigation district. This paper improved calculating methods of the capillary rise and percolation of the established model. The model was then applied to the upper, middle and lower reaches of the irrigation district. Conclusions by the model simulation were as follows: (I) The model could simulate the dynamics of water balance components of wheat-maize and cotton relatively accurately in the irrigation district. (II) Winter wheat and summer maize (wheat-maize) had the highest ET in the upper reaches, followed by the middle reaches and then the lower reaches. There was almost no difference for cotton ET in the upper, middle and lower reaches. (III) Irrigation amount of wheat-maize was 225-300 mm in the upstream, 300 mm in the middle reaches, and 500 mm in the downstream. Cotton irrigation quantity was 60-150 mm in the upper and middle reaches, and 60-390 mm in the lower reaches. (IV) Soil water basically showed a decreasing trend in growth periods of wheat-maize and cotton in the middle and lower reaches, its recharge was primarily from irrigation of wheat. Combined with other references, there was a trend of soil drying in the North China Plain. (V) Mean values of water use efficiency (WUE) of winter wheat, summer maize and cotton were highest in the middle reaches and lowest in the upstream and downstream.
  • Authors:
    • Rosen, C. J.
    • Bierman, P. M.
    • Venterea, R. T.
    • Lamb, J. A.
  • Source: Agricultural Systems
  • Volume: 109
  • Year: 2012
  • Summary: A survey was conducted in the spring of 2010 to characterize the use of nitrogen (N) fertilizer on corn ( Zea mays L.) by Minnesota farmers in the 2009 growing season. Detailed information on synthetic N fertilizer management practices was collected from interviews with 1496 farmers distributed across all of the corn growing regions in the state. The total amount of corn they grew represented 6.8% of the ha of corn harvested in Minnesota in 2009. This report summarizes data on: (1) N fertilizer rates, (2) major N sources (excluding manures), (3) application timing of the major N source, (4) use of nitrification inhibitors, additives, and specialty N fertilizer formulations, (5) fertilizer placement and incorporation practices, (6) use of starter fertilizer, split and sidedress applications, and other N sources such as ammonium phosphates, (7) N fertilization of irrigated corn, and (8) use of soil testing as a fertility management tool. Many of the survey results are reported as statewide averages, but where regional differences occurred the data are broken down and presented separately for different parts of the state. This survey provides the most comprehensive set of data on N fertilizer use on corn that has been collected in Minnesota. The information can be used to target research and education programs to improve N management for both production and environmental goals. The statewide average N fertilizer rate was 157 kg N ha -1. Variable rate application was used to apply N by 23% of farmers. About 59% of surveyed farmers applied the majority of their N fertilizer in the spring before planting, 32.5% made their main N application in the fall, and 9% sidedressed the majority of their N after corn emergence. Most farmers used anhydrous ammonia (46%) or urea (45%) as their major source of N fertilizer, while 6.5% used a liquid N formulation as their primary N source. Soil testing was used as a fertility management tool on 84% of the surveyed fields in the last 5 years. Overall results indicate that N fertilizer use by Minnesota corn farmers is generally consistent with University of Minnesota Extension N management guidelines. Fertilizer N use could probably be improved by taking adequate N credit for previous soybean crops. In the South Central region of the state, fertilizer N recovery could potentially be improved by increased use of nitrification inhibitors with fall-applied anhydrous ammonia or by delaying anhydrous ammonia application until spring.
  • Authors:
    • Breland, T. A.
    • Bleken, M. A.
    • Bakken, L. R.
    • Lunde, H. W.
    • Borgen, S. K.
  • Source: Nutrient Cycling in Agroecosystems
  • Volume: 92
  • Issue: 3
  • Year: 2012
  • Summary: We applied a mechanistic ecosystem model to investigate the production and environmental performances of (1) current agricultural practice on two fields of a stockless organic cereal farm in southeast Norway and (2) alternative cereal-ley rotations and plowing time scenarios. Scenarios were simulated using historic weather data and a climate change scenario. Measured and simulated soil mineral N concentrations were generally low (1-4 g N m(-2)) and in good agreement. Simulated nitrate leaching was similar for the two fields, except when an extended period of black fallow weeding was practiced on one of them. Scenario simulations indicated that continuous cereal cropping undersown with a clover-grass winter cover crop performed best when evaluated by whole-rotation grain yield, the N yield/input-, and N loss/yield-ratios, and greenhouse gas emissions. However, the rotation had the largest soil organic matter losses. The N use and loss efficiency indicators were especially poor when ley years occurred consecutively and under fall plowing. Total greenhouse gas emissions were, however, smaller for the fall-plowed scenarios. In conclusion, our results indicated a modest potential for improving stockless systems by management changes in plowing time or crop rotation, which was hardly different in the climate change scenarios, although nitrate leaching increased substantially in the winter. Alternative strategies seem necessary to substantially improve the N-use efficiency in stockless organic grain production systems, e.g., biogas production from green manure and subsequent recycling of the digestate. Abandoning the stockless system and reintegrating livestock should also be considered.
  • Authors:
    • Kaspar, T. C.
    • Parkin, T. B.
  • Source: Soil Science Society of America Journal
  • Volume: 75
  • Issue: 6
  • Year: 2011
  • Summary: Measurements of soil CO 2 flux in the absence of living plants can be used to evaluate the effectiveness of soil management practices for C sequestration, but field CO 2 flux is spatially variable and may be affected by soil compaction and the percentage of total pore space filled with water (%WFPS). The objectives of our study were: (i) to evaluate the effect of wheel traffic compaction on CO 2 flux at two landscape positions with differing soil properties; and (ii) to examine the relationship of CO 2 flux and %WFPS under field conditions and a wide range of soil porosities. Carbon dioxide flux was measured near Ames, IA, in a no-till system without living plants using the closed chamber method on nine cylinders inserted into the soil at each measurement site and evenly spaced across three rows, an untracked interrow, and a tracked interrow. Flux, volumetric water contents, and soil temperature were measured on 12 or 13 d between day of the year (DOY) 164 and 284 in 2001, 2004, and 2005. Bulk density, soil organic C concentration, and soil texture were determined after DOY 284. On most days, CO 2 flux was less in the tracked interrow than in the row or untracked interrow positions. In all 3 yr, the cumulative flux of the tracked position was significantly less than one or both of the other positions. Landscape position did not affect the response of CO 2 flux to traffic. Percentage water-filled pore space was not a good predictor of surface CO 2 flux in the field. The effect of wheel traffic compaction on CO 2 flux should be considered when soil CO 2 flux is used to compare management practices.
  • Authors:
    • Kocyigit, R.
    • Rice ,C. W.
  • Source: Bulgarian Journal of Agricultural Science
  • Volume: 17
  • Issue: 4
  • Year: 2011
  • Summary: The soil surface CO 2 flux is the second largest flux in the terrestrial carbon budget after photosynthesis. Plant root and microbial respiration produce CO 2 in soils, which are important components of the global C cycle. This study determined the amount of CO 2 released during spring wheat ( Triticum aestivum L.) growth under no-till (NT) and conventional tillage (CT) systems. This experiment was conducted at Kansas State University North Agronomy Farm, Manhattan, KS, on a Kennebec silt loam. This study site was previously under dry land continuous corn production with NT and CT for more than 10 years. Spring wheat ( Triticum aestivum L.) was planted with two tillage systems (NT and CT) as four replicates in March. Surface CO 2 flux was measured weekly during plant growth. Soil water content at the surface (5 cm) tended to be greater in NT and decreased from planting to harvest. Soil microbial activity at the surface was usually higher in NT and decreased from planting to harvest, while activity was constant in the deeper depths. The higher microbial activity at the surface of NT occurred after 60 days of planting where soil water content was the most limiting factor on microbial activity. Soil CO 2 flux varied in response to changes in soil water content and the variation and magnitude of the increase was greater at higher soil water contents. Conventional tillage released 20% more CO 2 to the atmosphere compare to NT after 10 years in the North American Great Plains Regions.
  • Authors:
    • Sanadze, E.
    • Weismiller, R.
    • Kirvalidze, D.
    • Kvrivishvil, T.
    • Korakhashvili, A.
  • Source: Communications in Soil Science and Plant Analysis
  • Volume: 42
  • Issue: 7
  • Year: 2011
  • Summary: In 2006, the International Organization of Christian Charities (IOCC) began a program in the country of Georgia to establish an improved dairy enterprise in the villages of Minadze and Ghreli in the Akhaltsikhe district. To correctly determine the fertility requirements for the use of either mineral or organic fertilizer materials for improving soil fertility for legume grain crops (beans, peas, soybeans, etc.) and perennial pastures (a mixture of perennial cereal grasses and perennial legumes) and for the proper management of these soils, it was necessary to understand the geomorphic, chemical, and physical characteristics of the soils of this region. Soils of this region belong to a sub-type of Cinnamonic Calcareous soils. The characteristics of these soils as well as their fertility and soil management needs were ascertained. Appropriate amounts of mineral and organic fertilizers needed for the proper growth of legume crops and perennial pastures as well as timing of application are presented.