Desertification of Western Maharashtra: Causes and possible solutions. I. Comparative growth of eight tree species

Abstract

In the low rainfall tract of Western Maharashtra, the degraded area that can be called a desert in the making is 2.28 million ha out of a total of 5.7 million ha or 40% of the area. The main causes of this desertification are overcultivation coupled with deforestation and overgrazing. The problem is made more acute by the increasing human and animal population, and the fact that rainfall is undependable and of high intensity. The trend of desertification can be reversed by (a) closing the area to grazing and uncontrolled wood cutting, (b) implementation of time-tested soil and water conservation measures and (c) large scale planting of suitable forage grasses and legumes as well as arid zone species of trees. The main research thrust of the trials with promising species of trees was to determine their suitability to wastelands and to investigate methods of establishing them rapidly and economically. Thus the effect of fertilization and spacing was examined for the following eight tree species: Acacia albida, A. nilotica var. cupressiformis, A. nilotica var. indica, Albizia lebbek, Cassia siamea, Dalbergia sissoo, Leucaena leucocephala, Melia azedarach and Prosopis juliflora. The two spacings used were 5 × 0.6 m and 3 × 1 m and the three fertilizer doses were 0:0:0, 50:50:50 and 100:100:100 kg N:P 2O 5:K 2O per ha. A factorial design with nine plant selections, three fertilizer treatments, two spacings and three replicates was used. A total of seven irrigations were applied from October 1983 to February 1984. At 15 months of age the average basal stem diameters of L. leucocephala and M. azedarach were significantly superior to all the other species. The average plant height of L. leucocephala, at 2.38 m, was superior to all other species. The use of fertilizer led to significant improvements in performance; however, there was little difference between using a dose of 50 kg ha −1 or 100 kg ha −1. An interaction was found to exist between the species and spacings. L. leucocephala and M. azedarach showed better performance at the spacing of 5 × 0.6 m and D. sissoo and P. juliflora performed better at 3 × 1 m. C. siamea at 62% had the lowest survival rate.