Performance of exotic Acacias as fodder species on arid salt affected soils in Rajasthan and Little Rann of Kachchh, Gujarat.
Salt affected soils dominantly occur in arid and semi-arid regions and generally remain unutilized due to various stresses. In India, out of total 6.73 m ha salt affected soils, states of Rajasthan, Gujarat, Haryana and Punjab account for about 50%. Selection of salt tolerant trees/shrubs is very important to increase productivity of these soils. Exotic Acacias, especially Acacia ampliceps (salt wattle) being fast growing shrub/small trees from North-Western Australia offers potential to grow and yield fodder on alkaline/saline soils. At Arid Forest Research Institute, Jodhpur; research was initiated first in 1998 on sandy to loamy sand soil located in Jodhpur district of Rajasthan, and later in 2007 on black silty clay soil in the Little Rann of Kachchh, Gujarat to evaluate exotic Acacias, namely A. ampliceps and Acacia bivenosa along with indigenous fodder plant species. For site in Jodhpur, the planting treatments were: depths of soil (deep and shallow) and doses of gypsum (G0 - contrrol and G1 - gypsum @100% soil's requirement) whereas, for site in Kachchh, the treatments were planting techniques using 1 different materials viz., T1: control, T2: FYM, T3: wheat straw, T4: FYM + wheat straw, T5: bajara (pearl millet) husk, and T6: bajra husk + FYM. The objectives for these field trials were to assess survival, growth and biomass (fodder) production potential of exotic Acacias under different planting techniques in two different environmental settings. Results of 72 months growth of A. ampliceps on loamy sand salty soil in Jodhpur, and 42 and 48 months of A. ampliceps and A. bivenosa shrubs, respectively on black silty clay soil in Kachchh are presented in this article. The findings revealed that increased soil depth and gypsum application positively influenced the growth and biomass production on loamy sand soil in Jodhpur, and maximum green biomass (12.05 kg tree-1) was yielded by gypsum treated plots in deep soil as well as in shallow soil. Minimum biomass was produced by control (without gypsum) in shallow soils. On black silty clay soil in Kachchh, performance of A. bivenosa was better than A. ampliceps. At 42 months of age, maximum green biomass yield (13 kg tree) from A. ampliceps was obtained from T3 (wheat straw), followed by T2 (FYM), and minimum (5.5 kg tree-1) from T4 (FYM + wheat straw). In case of A. bivenosa, after 36 months, maximum biomass yield (12.69 kg tree-1) was obtained in T3 (wheat straw), followed by T2 (10.22 kg tree-1) and minimum in control. Both the species flowered and produced viable seeds. Besides, natural germination of A. ampliceps was observed at both sites. They did not suppress the native vegetation and exhibited high potential to be introduced as fodder species in afforestation programmes targeting salt affected soils in arid Rajasthan and Rann of Kachchh, Gujarat.