Influence of Different Landuse Management on Soil Biological Properties and other C Fractions under Semi-AridBenchmark Soils of India: Global Theme on AgroecosystemsReport no. 41 uri icon

abstract

  • Fifty two pedons spread over 28 benchmark spots of Vertisols and Alfisols were studied for soil biological properties and other C fractions (soil microbial biomass c, soil respiration dehydrogenase activity, soil microbial biomass N, mineralizable N, water soluble C and soluble carbohydrates, water stable aggregates, water stable aggregates C, humic and fulvic acid C, etc.) in different systems viz., agricultural, horticultural, forest and wasteland. The agricultural system represents dominant crops namely cereals, soybean and cotton. The horticultural system represents mandarins. The forest systems represent teak and sal. The selections of benchmark spots were limited to a mean annual rainfall range from 1448 to 520 mm in semi-arid tropics. The present experiment was conducted under various bio-climatic condition such as sub-humid moist (>1200 mm), sub-humid dry (1200-100 mm), semiarid dry (1000-850mm), semi-arid moist (850-550 mm) and arid (<550 mm). The active pools of SMBC comprised 3.2 to 5.6 % of SOC in Vertisols and 1.2 to 5.7 %of SOC in Alfisols. WSC comprised 0.80 to14.1 % of SOC in Vertisols and 1.5 to 4.9 % of SOC in Alfisols. WSCarbohydrates comprised 15-40.3 % of SOC in Vertisols and 10.5 to 25 % of SOC in Alfisols. In sub-humid moist regions, the SMBC content followed the order: forest (teak)> soybean-wheat>paddy-wheat>cotton (HM). In sub-humid dry regions of Vertisols, the SMBC was maximum under horticultural system (citrus), followed by intercropping (cotton + pigeonpea) and mango-orchard. In semi-arid moist regions, SMBC and SR were higher under intercropping system (soybean+ pigeon pea) compared to soybean ?gram system. The soil biological activity in terms of SMBC, SMBN can be improved with concomitant increase of water-soluble carbon and carbohydrates by better management practices. Among field crops, legume-based intercroppingsystem (soybean + pigeonpea and greengram + pigeonpea) restored higher amount of SOC, SMBC compared to double crop in rotation (soybean-wheat/paddy-paddy cropping system). Among the horticultural-based cropping systems, citrus with high management has better SOC restoration compared to mango orchard. Cotton-based cropping system either as intercropping or sequential cropping registered least improvement of SOC storage. In Vertisols, the percentage of water stable aggregates and concentration of carbon in WSA was higher than Alfisols. Water stable aggregates, carbon concentration increased with decrease in size class. By and large, the maximum concentration of SOC in the water stable aggregates was observed in <0.1 mm size aggregates. In 0-30 cm soil depth, passive fraction of HA-C was relatively higher than FA-C in surface whereas FA-C increased with soil depth. The percent variations in passive fractions among different cropping systems were not pronounced as compared to active and slow pool of C

publication date

  • 2008