Enhancing forest productivity through afforestation on arid salt affected sandy soils in Rajasthan

Abstract

Soil salinity/alkalinity is an important factor adversely affecting soil health and plant productivity on arid salt affected soils. In India, 6.73 m ha area has been reported to be salt affected of which about 50 % (2.98 m ha) occurs in Rajasthan, Gujarat, Haryana and Punjab. Utilization of these salt affected areas has become necessary owing to increasing need for fodder and fuel wood for rural poor but they require specific approaches for their reclamation. Experimental trials were conducted on lithic, calcid, coarse sandy to loamy sand salt affected soil in Jodhpur, Rajasthan to find out suitable exotic and indigenous plant species and planting practice to increase the production. Results on performances of various tree and shrub species with management practices showed that Salvadora persica (L) a preferential halophyte, evergreen multipurpose indigenous tree proved most versatile with 85.2 to 66.7 %, survival in different treatments at 72 months of age . Effect of treatments was positive and T6 (gypsum + 9g N) was the best treatment attaining 207cm of height and 212 cm of crown diameter, which was 38 % and 24 % more than the untreated plants. It produced 12.0 kg/tree of above ground biomass followed by 10.7kg and 8.8kg in T8 (gyp + 27g N) and T2 (9 g N) respectively which was 71%, 53% & 27% more than the control (untreated plants). There is no decrease in survival even after 18 years. In another experimental set up tree species like Sueada nudiflora, Atriplex lentiformis and Atriplex stocksii performed well on different types of mound techniques i.e. Double ridge mound (DRM) and Circular dished mound (CDM). Based on survival and growth S. nudiflora was the best species followed by A. lentiformis and A.stocksii. Overall DRM was the best planting practice producing maximum mean dry biomass. C. mopane (Kirk et Benth), an exotic species of south central Africa, maintained 89 % overall mean survival after five years and plants on CDM structure attained 113 & 158 cm as mean height and crown diameter respectively as compared to 101 & 151 cm for control at 60 months of age. Overall plants on CDM recorded a mean 1.45kg green biomass yield/plant which is 5.9% more compared to control (1.37kg) .