干旱区生态环境知识资源中心

Tecomella undulata L. (Rohida) is a common tree of traditional agroforestry systems of the northwestern dry region of India. Seedlings of T undulata at 1666, 833 and 416 stem ha(-1) stand densities were thinned in July 1995 to maintain them at 417 (D-1), 278 (D-2) and 208 (D-3) stem ha(-1), respectively, to find out the optimum density with tree age. Vigna radiata (L.) Wilczek (mungbean) and Pennisetum glaucum (L.) R.Br. (pearl millet) were the intercrops. The increase in height and collar diameter between June 1995 and June 2002 was 2.6 and 3.3 fold in D, to 2.0 and 2.3 fold in D-3 plots, respectively. Grain and straw yield was lower under intercropping than with a sole agricultural crop. Production was significantly lower (p < 0.01) in D-1 plot. It was highest in D-2 Plot during 1995 and 1996 and in D-3 plot during 2000 and 2001. The trees produced a utilizable biomass of 2.5 to 3.2 t ha(-1) in 1996 and 3.63 to 4.08 t ha(-1) in 1999. Soil water content differed significantly (p < 0.05) in deeper soil layers and was lower near the root zone than at 2 m distance and in the centre of four trees. Utilization of soil water was more when pearl millet rather than mung bean was the intercrop. Soil PO4-P and NO3-N were lower and NH4-N was higher near the root zone than at 2 m distance. Two hundred and seventy eight stems ha(-1) was most favourable for crop production at the age of 6-7 years and 208 stem ha(-1) at 10-11 years.