Nutrient utilization in soybean weed ecosystem under different varieties, crop geometries and weed control treatments

摘要

A field experiment was conducted during rainy season of 2001 and 2002 at Udaipur. Results revealed that variety JS-335 was found most efficient in total N and P uptake at harvest as compared to NRC-37 and JS 71-05 though there was no significant difference in N and P uptake by monocot, dicot and total weeds at 40, 60 DAS and at harvest. Both the crop geometries did not show any significant effect on N and P uptake by both weeds and crop. At harvest, all the weed control treatments resulted in significantly lower uptake of N and P by monocot and dicot weeds and also total uptake compared to weedy check, except uptake by dicot weeds due to fenoxaprop-p-ethyl 75 g/ha post emergence (POE). All the weed management practices significantly enhanced total N and P uptake by soyabean at 60 DAS and at harvest as compared to weedy check. Lower N and P uptake (total) by weeds and higher N and P uptake by soyabean were recorded with two hand weeding at 20 and 40 DAS and colomazone+HW at 40 DAS and followed by colomazone 1.0 kg/ha pre emergence (PE)..