Soil residual nitrogen under various crop rotations and cultural practices

Abstract

Crop rotation and cultural practice may influence soil residual N available for environmental loss due to crop N uptake and N immobilization. We evaluated the effects of stacked vs. alternate-year crop rotations and cultural practices on soil residual N (NH4-N and NO3-N contents) at the 0-125 cm depth, annualized crop N uptake, and N balance from 2005 to 2011 in the northern Great Plains, USA. Stacked rotations were durum (Triticum turgidum L.)-durum-canola (Brassica napusL.)-pea (Pisum sativum L.) (DDCP) and durum-durum-flax (Linum usitatissimum L.)-pea (DDFP). Alternate-year rotations were durum-canola-durum-pea (DCDP) and durum-flax-durum-pea (DFDP). Both of these are legume-based rotations because they contain legume (pea) in the crop rotation. A continuous durum (CD) was also included for comparison. Cultural practices were traditional (conventional tillage, recommended seeding rate, broadcast N fertilization, and reduced stubble height) and improved (no-tillage, increased seeding rate, banded N fertilization, and increased stubble height) systems. The amount of N fertilizer applied to each crop in the rotation was adjusted to soil NO3-N content to a depth of 60 cm observed in the autumn of the previous year. Compared with other crop rotations, annualized crop biomass N was greater with DCDP and DDCP in 2007 and, but was greater with DDFP than DCDP in 2011. Annualized grain N was greater with DCDP than CD, DFDP, and DDFP and greater in the improved than the traditional practice in 2010 and 2011. Soil NH4-N content was greater with CD than other crop rotations in the traditional practice at 0-5 cm, but was greater with DDCP than CD and DDFP in the improved practice at 50-88 cm. Soil NO3-N content was greater with CD than other crop rotations at 5-10 cm, but was greater with CD and DFDP than DCDP and DDCP at 10-20, 88-125, and 0-125 cm. Nitrate-N content at 88-125 and 0-125 cm was also greater in the traditional than the improved practice. Nitrogen balance based on the difference between N inputs and outputs was greater with crop rotations than CD. Increased N fertilization rate increased soil residual N with CD, but legume N fixation increased N balance with crop rotations. Legume-based crop rotations (all rotations except CD) reduced N input and soil residual N available for environmental loss, especially in the improved practice, by increasing crop N uptake and N immobilization compared with non-legume monocrop. RightsWorks produced by employees of the U.S. Government as part of their official duties are not copyrighted within the U.S. The content of this document is not copyrighted. AbstractCrop rotation and cultural practice may influence soil residual N available for environmental loss due to crop N uptake and N immobilization. We evaluated the effects of stacked vs. alternateyear crop rotations and cultural practices on soil residual N (NH 4 -N and NO 3 -N contents) at the 0-125 cm depth, annualized crop N uptake, and N balance from 2005 to 2011 in the northern Great Plains, USA. Stacked rot...

Determination of nitrogen balance in agroecosystems

“…Nitrogen fertilization rates to same crops also depend on crop varieties and differ from one location to other due to variations in residual soil N content to a depth of 60 cm at crop planting and N mineralization potential of the soil during the growing season. A depth of 60 cm is chosen to determine soil residual N content because it has been assumed that crop roots usually grow to that depth for N uptake [6] , [7] , [8] . This often results in analysis of soil samples for NO 3 -N content and N mineralization potential before crop planting.…”

“…Crop N requirements are usually determined by yields that are economically profitable, although yields may not be at their maximum levels [8] . Crop responses to N fertilization vary with soil NO 3 -N content and N mineralized from crop residue and soil organic N during the growing season.…”

“…Crop responses to N fertilization vary with soil NO 3 -N content and N mineralized from crop residue and soil organic N during the growing season. Maximum attainable yield for a crop vary with soil and climatic conditions, nutrient supply, and competitions with weeds and pests [8] . Therefore, it is necessary that soils be tested for residual N content and potential N mineralization (if possible) and adjusted for N rates before N fertilizers are applied so that N requirements for crops can be optimized and potential for N losses minimized.…”

“…This is due to differences in N fertilization rates, crop N removal, N mineralization and immobilization, atmospheric N depositions, N concentration in irrigation water, biological N fixation, and N losses through various processes among years and locations. Fine-textured soils retain more N and reduce N losses compared with coarse-textured soils, which can reduce N fertilization rates, although predominant N losses are gaseous losses and N leaching in fine-and coarse-textured soils, respectively [8] , [14] . Soil and crop management practices, such as no-till and crop rotation, may result in different N fertilization rates to same or different crops, soil N retention, and N losses compared with conventional till and monocropping [23] .…”

Distribution of Mineral Nitrogen in Soil in Relation to Risk of Nitrate Leaching in Farms with Irrigated Vegetables and Early Potatoes

“…Our results suggest that specific crop rotations, alternating vegetables with low N efficiency and shallow roots and other crops (cereals, maize, sorghum) are effective tools for the reduction of the risk of leaching losses. These standard approaches of reduction of leaching and run-off losses (Cameira & Mota 2017;Li et al 2017;Sainju et al 2017) should be enhanced by new methods, such as the use of biofertilizers. CONCLUSIONS 1.…”