Title: Nutrient removal by weeds and maize (Zea mays)
Abstract: Maize (Zea mays L.) is one of the most influenced by different weed-management important grain crops grown in Andlira practices. The weeds under unweeded check Pradesh with an average yield of 1,700 kg1 recorded the highest uptake of NPK ha compared with national average of 1,474 nutrients on account of higher weed dry kglha. There is vast scope to raise its weight. The weed-management practices productivity through agronomic caused significant reduction in N, P and K management. Weeds form the major factor uptake by weeds. The treatments atrazine @ in limiting the yield by causing considerable 1.0 kglha + 2, 4-D Na salt @ 0.5 kglha and nutrient loss in maize crop recorded up to atrazine @ 1.0 kglha + glyphosate @ 1.0 62, 24 and 124 kglha of N, P and K kglha were found effective next only to the respectively (Vishwanath, 1978). farmers, practice in giving higher crop-dry A field experiment was conducted atthe matter as well as N, P and K uptake by the Agricultural College Farm, Rajendranagar, crop compared with other treatments Hyderabad, during the rainy season (kharif) including the unweeded check which of 199 1, to asses; the removal of N, P and K recorded the lowest values. The former 2 both by crop and weeds under different treatments were at par with each other. This weed-management practices as treatments was probably due to higher crop-dry matter (Table 1). The experimental soil was sandy on account of less weed competition as loam (Alfisols) in texture with low in evident from low dry-weed weight. available N (226 kglha) and P (18.5 kglha), Angiras and Singh (1989) also reported and medium in available K (235 kglha) the increaseduptake of NPK nutrients by having pH 7.6. The experiment was laid out maize crop due to chemical weed control in randomized block design and replicated compared with the unweeded control. It is thrice. Maize cv. DHM 105 was sown on 2 evident that the crop-weed competition in July 1991 and harvested on 21 October the unweeded check exerted an adverse 1991. Estimated values of N, P and K effect on the uptake and utilization of uptake by weeds as well as maize plant at nutrients by crop and thus result in low harvest are presented in Table 1. croped dry matter. The removal of nutrients by weeds The nutrient uptake by the crop can be showed a great impact on the availability of increased by effectively checking the weed nutrients to the crop thus affecting its dry- growth with the pre-emergence application matter accumulation. The nutrient removal of atrazine @ 1.0 kglha + post-emergence by both crop and weeds were significantly application of 2,4-D Na salt @ 05 kg/ha or