Biologically-mediated nutrient availability in the soil is largely dependent on soil organic matter (SOM) decomposition and mineralization processes. The light fractions of SOM obtained by floatation of the sand-size fraction in a silica suspension (LL 150–300 μm and < 1.13 g cm−3) and floatation of whole soil in sodium iodide (NAL < 1.7 g cm−3) were previously found to be strongly affected by maize and legume cropping systems. The objective of this study was to assess the anaerobic and aerobic N mineralization rates of LL NAL and whole soil after the eighth cropping season (4 y) in seven maize and legume cropping systems. Significantly greater (P < 0.05) N mineralization in whole soil LL and NAL resulted from the seasonal additions of Gliricidia sepium prunings to continuous maize than from continuous maize with removal of crop residues and from a gliricidia stand with prunings removed. Aerobic and anaerobic N mineralization in whole soil from the seven cropping systems correlated (P < 0.05) with aerobic N mineralization in LL and NAL which in turn correlated with the N concentration and amount of N in the respective fraction. Amount of LL-N but not LL-C or dry weight of LL correlated with anaerobic and aerobic N mineralization of whole soil. Dry weight amount of N and amount of C in NAL were not correlated with whole soil mineralization. These results suggest that amount of N in light fraction SOM merits further examination as a sensitive measure of biologically-mediated N availability.
00155-1&apiKey=3948bb216041dbffcb29a618defafc29&httpAccept=image%2Fjpeg)
DOI:
http://dx.doi.org/10.1016/S0038-0717(96)00155-1Altmetric score:
Dimensions Citation Count:
Publication year
1996
Authors
Barrios, E.; Buresh, R.J.; Sprent, J.I.
Keywords
Agroforestry, Agrosilvicultural systems, Alley cropping, Cropping systems, Degradation, Mineralization, Nitrogen, Plant population, Pruning, Soil organic matter
