The Effects of Grazing on the Structure and Productivity of the Vegetation near Pilani, Rajasthan, India

Abstract

Capparis decidua, Maytenus senegalensis and Balanites aegyptiaca do occur while trees of Prosopis cineraria are quite abundant. The economy of these sparsely populated areas is based on livestock production. Consequently the herbaceous primary production is of vital importance. The present work was undertaken to study the effects of grazing on the structure and productivity of the vegetation on three sites near Pilani. In this paper, the number of plant individuals and species, standing crop of above and underground biomass, standing dead vegetation, litter, plant pigments and the net vegetation production of the above and underground biomass have been assessed. DESCRIPTION OF THE STUDY SITES Areas were selected for study near Pilani (28023 N, 75?37 E) at an altitude of about 350 m. The sites were: I, sandy plains; II, hard ground; and III, stabilized dunes. Sites I and II lack trees and shrubs, while site III supports a thin scrub consisting of Capparis decidua, Balanites aegyptiaca, Lycium europaeum, Maytenus senegalensis and Prosopis cineraria. Herbaceous species, which are of common occurrence on more than one site, include annuals such as Dactyloctenium aegyptium, Eragrostis ciliaris, E. poaeoides, Tragus biflorus and Gisekia pharnaceoides while the perennials comprise Convolvulus microphyllus and Tephrosia purpurea. The rooting depth of annuals varies from 20-30 cm while that of perennials may be beyond 40 cm. However, the major portion of the dry matter of roots is found to lie within 25 cm of the soil surface. Study plots in sites I, II and III cover