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Nitrogen Balance and Biomass Production of Newly Established No‐Till Dryland Agroecosystems
Author(s) -
Wood C. W.,
Peterson G. A.,
Westfall D. G.,
Cole C. V.,
Willis W. O.
Publication year - 1991
Publication title -
agronomy journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 131
eISSN - 1435-0645
pISSN - 0002-1962
DOI - 10.2134/agronj1991.00021962008300030001x
Subject(s) - agronomy , environmental science , perennial plant , sorghum , grassland , soil water , no till farming , leaching (pedology) , biomass (ecology) , agroecosystem , biology , soil fertility , agriculture , soil science , ecology
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 NO 3 –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 NO 3 –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.