Effect of Weed Management Practices on Weed Control Index, Yield and Yield Components of Sweet Corn

Introduction

Sweet corn (Zea mays corn var. saccharata var. rugora also called as Indian corn, sugar corn and popcorn) is a variety of maize with high sugar content. Due to its delicacy and sweet flavors and crop nature it has a prominent place as an indispensable ingredient in many fancy dishes of today’s cuisine and it is highly nutritive value crop. To augment higher yield crop per unit area, proper weed management is most important factor which cause marked effect on the growth and eventually the yield of a crop. Further weed causes a huge loss, and the magnitude of losses largely depends upon the composition of weed flora, period of crop crop-weed competition and its intensity. The season –long weed competition caused considerable yield loss in maize [1] weed reduce crop yield by competing for light, water, nutrient and carbon dioxide, interfere with harvesting and increase the cost involved in crop production [2]. If weed growth is minimized during critical period of crop weed competition, the yield can be equivalent to that of weed free yield. Weed management can be formulated to minimize the losses due to weeds by means of integrated approach strategy. Manual weeding alone is not sufficient to ensure adequate weed control in maize field. It should be supplemented with chemical or herbicide for effective weed control. Choice for selection of safe herbicides determines the success of weed control programme. But it is difficult to find broad spectrum of herbicides as herbicides are often crop specific. Pre-emergence herbicides ensure significant promising weed control and save the crop from initial weed competition and nutrient drain. Similarly the post emergence herbicide also has a significant role in reducing the crop weed competition at the time of critical growth stages of the crop.

1 as pre-emergence herbicide at 3 DAS + paraquat 0.5 kg ha-1 as post-emergence herbicide at 21 DAS, hand weeding at 20 DAS, hand weeding at 40 DAS, hand weeding at 20 & 40 DAS and weedy check. All the recommended package of practices except weed control was followed for raising the sweet corn. Sweet corn f1 hybrid, sugar-75 was sown with a seed rate of 7.5 kg ha-1 in rows spaced at 60 x 30 cm. Irrigation was adjusted with weather condition and receipt of rain including pre sowing once. Weed population and biomass was recorded at 30 and 60 DAS by using quadrat of 0.25m2 fixed randomly at four places in each plot. Data on weed biomass, WCI, crop yield components and yield was recorded from net plot areas. Results and Discussion

Materials and Methods

A field experiment with 10 treatment was laid out in randomized block design, replicated thrice, were undertaken at the experimental farm, Annamalai University, Department of Agronomy, Faculty of Agriculture, Annamalai Nagar during kharif (July – October) 2013 in sweet corn. Soil was clayey loam with pH 7.8, organic carbon 0.31%, and low in nitrogen (246.5 kg ha-1), medium in phosphorous (16.7 kg ha-1) and high in potassium (327.5 kg ha-1). The treatments comprised of atrazine 1 kg ha-1 as pre-emergence herbicide at 3 DAS, atrazine 1 kg ha-1 as pre- emergence herbicide at 3 DAS + one hand weeding at 20 DAS, atrazine 1 kg ha-1 as pre- emergence herbicide at 3 DAS + one hand weeding at 40 DAS, paraquat 0.5 kg ha-1 as post- emergence herbicide at 21 DAS, paraquat 0.5 kg ha-1 as post-emergence herbicide at 21 DAS + one hand weeding at 40 DAS, atrazine 1 kg ha-

Conclusion

On the basis of the experimentation, it can be concluded that twice hand weeding was comparable with atrazine 1 kg ha-1 as pre emergence herbicide at 3 DAS + one hand weeding at 40 DAS and was more efficient in controlling weeds.