Influence of sowing orientation and intercropping of chilies on onion yield and its associated weeds in Peshawar, Pakistan

摘要

A field trial was carried out at the Agronomy Research Farm of the The University of Agriculture Peshawar during the onion sowing season of 2015 to find out the effect of sowing orientation and intercropping chilies ( Capsicum annum L.) on onion ( Allium cepa L.) yield and the associated weeds. A two factorial experimental design was used for the experiment data analysis, with the experiment replicated three times. The sowing orientation was termed as Factor A with two levels i.e. North-South and East-West wards sowing, and Factor B was the intercropping treatments with five levels viz. sole onion, onion 1 row + chili 1 row (1:1), onion 1 row + chili 2 rows (1:2), onion 2 rows + chili 1 row (2:1), and onion 2 rows + chili 2 rows (2:2). Data were taken on weed density m -2 , weed fresh biomass (kg ha -1 ), plant height (cm) of onion, biological yield (t ha -1 ), bulbs yield of onion (t ha -1 ), chili yield (t ha -1 ) and Land equivalent ratio (LER). The results indicated that sowing orientation, intercropping and their interaction significantly affected the studied parameters of onion crop, intercrop and weeds. Regarding the sowing orientation, E-W sowing showed significant increase in weed density (94.27 m -2 ), weed biomass (1323 kg ha -1 ) and onion plant height (35.69 cm) as compared to the lower weed density (84 m -2 ) and biomass (1240.67 kg ha -1 ) in north-south sowing. On the other hand, the N-S sowing resulted in increased biological yield (3848.73 kg ha -1 ) and bulb yield (20.73 tons ha -1 ). The yield of chili was higher (6.98 t ha -1 ) in North-South sowing than in east-west plots (6.20 t ha -1 ). As far as the intercropping effect is concerned, maximum weed density (119.17 m -2 ) and biomass (2118.5 kg) were recorded in the monocrop treatments as compared to the intercropping ones. In addition, biological (4625.84 kg) and bulb yields (23.21 kg ha -1 ) were highest in sole onion plots, while intercropping with a ratio of one row of onion and two rows of the intercrop resulted in minimum weed density (48.5 m -2 ), weed biomass (853.17 kg), biological yield (2430 kg ha -1 ) and bulb yield (13.39 t ha -1 ). The onion plant height was maximum (40.62 cm) in plots with intercropping in ratio of onion 2 rows + chili 2 rows. The chili yield was maximum (8.58 t ha -1 ) in sole chili plots while minimum in the intercropping treatment of onion 2 rows + chili 2 rows (4.50 t ha -1 ). It is thus inferred that sowing in the north south direction, with intercropping chili with onion in ratio of 1:1 could be a best environment friendly addition in the weed management program for yield enhancement of onion crop.