63.Effect of wheat planting density and weed management on nutrient accumulation and uptake of wheat and weeds under agro-climatic condition of Quetta-Pakistan

Abstract

Weed infestation ranked first as main constraint in agriculture production system because both weeds and crop striving for space, light, water and nutrients. For this purpose, a field trial was designed in CRBD across factorial management during 2017-18. Four different seed rates (100, 125, 150 and 175 kg ha^-1) tested against weed management practices (no weeding, herbicide application, hand hoeing and allelopathic weed control) and replicated thrice. The results revealed that seed rate of 125 kg ha^-1 increased grain yield (4.24 t ha^-1). The wheat physiological traits were also improved on this seed rate with CGR (16.80 g m^-2 day^-1) and NAR (4.78 16.80 g m^-2 day^-1). This medium seed rate also increased leaf N, P and K concentration by 34.72, 56.76 and 31.79% over 100 kg ha^-1, 11.56, 20.83 and 6.48% over 150 kg ha^-1. However, higher seed rate reduced its uptake by 48.84, 57.92 and 11.28% over 125 kg ha^-1 and 29.84, 60.00 and 10.68% over 150 kg ha^-1. The weed whole plants N, P and K concentration and uptake reduced on higher seed rates. While, herbicide application effectively controlled weeds by 90.56% followed by hand hoeing (84.55%). According to linear regression analysis, a positive and significant correlation was noted between grain yield and CGR (r = 0.90) and grain yield and NAR (r = 0.93).  Consequently, it can be established from this study that weeds controlled by herbicide application and crop sown with seed rate of 125 kg ha^-1 minimized weed crop competition and increased crop yield.

Keywords: NPK concentration in wheat leaf and weeds; NPK uptake by wheat and weeds; planting densities; Wheat; Weeds

http://dx.doi.org/10.19045/bspab.2019.80106