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Agronomy Journal Abstract -

Nitrogen Balance and Biomass Production of Newly Established No-Till Dryland Agroecosystems


This article in AJ

  1. Vol. 83 No. 3, p. 519-526
    Received: May 31, 1990

    * Corresponding author(s):
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  1. C. W. Wood ,
  2. G. A. Peterson,
  3. D. G. Westfall,
  4. C. V. Cole and
  5. W. O. Willis
  1. D ep. of Agronomy and Soils, 202 Funchess Hall, Auburn Univ., AL 36849-5412
    N atural Resources Ecology Lab., Fort Collins, CO 80523
    U SDA-ARS, Fort Collins, CO 80523



Soil-crop management affects the soil-N balance and, thus, has a direct bearing on soil productivity. This study determined the effects of cropping intensity (crops/time) under no-till and grassland establishment on aboveground biomass production and the system-N balance after 4 yr (1985-1989). The effects were examined across toposequences in the West Central Great Plains that had been tilled and frequently fallowed for >50 yr. Production systems included wheat (Triticum aestivum L.)-fallow (WF), wheat-corn (Zea mays L.) or sorghum (Sorghum vulgare L.)-millet (Panicum miliaceum L.)-fallow (WCMF), and perennial grass (CG). Intense agronomic systems (WCMF) had greater aboveground production, greater N uptake, and greater percent plant residue retention than WF. Continuous grass systems had less aboveground production and N uptake but greater percent plant residue retention than agronomic systems. Soil-profile NO3-N was lower under WCMF systems than WF systems, but organic N showed the opposite trend implying that more intense systems are at less risk for NO3-N leaching, and have greater potential for replenishment of soil-organic N via enhanced immobilization. Aboveground biomass production and plant residue production increased downslope, but slope position had little effect on plant-N uptake, plant residue retention, or soil-N dynamics. Imposing no-till and perennial grassland systems created a N-balance disequilibrium, but more time will be required to ascertain the trajectory of N loss or gain due to establishment of no-till or grassland management on these soils.

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