Effect of spacing and nitrogen on productivity and nitrogen use indices of colocynth under rainfed condition

Abstract

An experiment on effect of intra row plant spacing and nitrogen nutrition on the yield attributes, yields, nutrient accumulation and nitrogen use efficiencies of colocynth (Citrullus colocynthis) was carried out during 2005 and 2006 under rainfed condition. The experiment consisted of 16 treatments with 4 intra–row plant spacings (50, 75, 100 and 150 cm) and 4 nitrogen levels (0, 20, 40 and 60 kg/ha). Plant spacing at 150 cm produced higher fruits/plant, average size and weight of fruits over closer plant spacings. The yields of plant dry matter, dry fruit, seed and oil per hectare recorded significantly the highest with 75 cm plant spacing. Nitrogen and phosphorus uptake (kg/ha) by the leaf, vine and total biomass was recorded maximum with 75 cm spacing while 100 cm spacing recorded maximum uptake in rind, pulp, cotyledon, testa and fruits. Successive increase in nitrogen levels up to 40 kg/ha recorded significantly higher yield parameters per plant and yields per hectare. The uptake of nitrogen and phosphorus in leaf and vine increased up to 60 kg N /ha while the maximum uptake of these nutrients in fruit (rind, pulp, cotyledon and testa) and total biomass was recorded with 40 kg N/ ha. Significantly higher values of agronomic nitrogen use efficiency (ANUE) and apparent nitrogen recovery (ANR) were recorded with 75 cm plant spacing and 20 kg N/ha due to higher fruit yields per unit area.