Abstract
AbstractImposing no‐till and lower fallow frequency on soils previously managed under tilled and frequent fallow systems may alter soil organic C and N concentrations and activity (potential mineralization). This study was conducted to determine the effect of cropping intensity (number of crops/unit time) on surface soil (0‐5 cm) C and N activity after 3.5 yr of no‐till management. The effect was examined across three soil catenas in the West Central Great Plains that were previously managed under tilled and alternate crop‐fallow systems for >50 yr. Production systems included the less intensive wheat (Triticum aestivum L.)‐fallow (WF), and the more intensive wheat‐corn (Zea mays L.)‐millet (Panicum miliaceum L.)‐fallow (WCMF). After 3.5 yr of no‐till, potential C and N mineralization, C turnover, and relative N mineralization were 61,39,36, and 43% greater under WCMF than WF, respectively. Footslope soils had greater potential C and N mineralization than summit or backslope soils, but lower C turnover and relative N mineralization, which was probably due to long‐term accumulation of recalcitrant C and N compounds. Differences in potential soil C and N activity between cropping systems were due to greater surface organic C concentrations under WCMF (mean = 10.88 g kg−1) than WF (mean = 9.60 g kg−1), which were related to cumulative plant residue additions over the 3.5‐yr‐study period (mean = 9.01 and 7.04 Mg ha−1 for WCMF and WF, respectively). It appears that potentially active surface soil organic C and N are very sensitive to change in cultural practices, and are increased by greater cropping intensity under notill management.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call