Primary production and nutrient dynamics of grazing land in the semi arid region of Madurai.

摘要

The net primary production, dry matter dynamics and uptake, transfer and release of nutrients in the semiarid grazing land at Madurai, Tamil Nadu, India, were studied. Heteropogon contortus was the dominant species in the grazing land. The total net production of the grazing land was 1618.3 g m2/year. Of the total net production, approximately 64% was attributed to the aboveground and 36% to the belowground production. The rate of belowground disappearance was higher than that of litter. The maximum concentration of nutrients occurred in the live shoot component followed by belowground parts. Litter had the lowest concentration of all nutrients. The nutrients that accumulated in the plant components were in the order: N > K > Ca > Mg > P. A large amount of nutrients were stored in the soil and a little was distributed to various plant parts. The uptake of nutrients in the aboveground parts were higher than the belowground parts. The nutrients released to the soil through root decay were higher than the nutrients released through litter disappearance..