Comparative field performance of some agricultural crops under a canopy of Populus deltoides and Ulmus wallichiana

The performance of maize, beans and sunflower was evaluated under a canopy of Populus deltoides and Ulmus wallichiana at Faculty of Agriculture, Wadura. The germination, growth and yield of the three test crops were suppressed under both tree species. The reduction, however, decreased when the cultivation of test crops was continued for three years. The inhibition potential generally is in the order of P. deltoides < U. wallichiana for maize and sunflower and P. deltoides > U. wallichiana for beans. Available soil N, P and K increased under the canopy of the selected tree species. The soils under U. wallichiana were more fertile than those under P. deltoides. Chromatographic investigation of extracts showed that the soils under P. deltoides and U. wallichiana differed in their composition of phenolic acids and phenolic glycocides. Except for caffic acid, all other allelochemicals disappeared and were no longer recovered in soil samples obtained after the second or third year of cultivation. Tree-crop compatibility can be explored in greater detail for improved management of traditional agro-ecosystems in Kashmir to increase the overall productivity of the land.