Growth and yield of coriander (Coriandrum sativum) as influenced by weed management and nitrogen levels

A field study was carried out during winter (rabi) season of 2007–08 and 2008–09 at Jobner, Rajasthan to evaluate the effect of weed-management treatments and nitrogen levels on weed-control efficiency and growth, yield and economics of coriander (Coriandrum sativum L.). Two hand-weedings done 20 and 40 days after sowing and pendimethalin at 1.0 kg/ha + hand-weeding at 40 days after sowing were the most effective in reducing the density and dry weight of weeds and improving the weed-control efficiency. Oxadiargyl at 0.06 kg/ha + hand-weeding at 40 days after sowing represented the lowest weed density and controlled the weeds to the extent of 94.9%. Two hand-weedings done at 20 and 40 days after sowing recorded the highest plant height, umbels/plant and test weight. It also provided the maximum seed and straw yields (1.37 and 2.58 t/ha) of coriander that were 164.7 and 116.9% more than unweeded control respectively. Pendimethalin at 1.0 kg/ha + hand-weeding at 40 days after sowing was also found equally effective in increasing the growth and yield attributes as well as yield. The highest number of branches/plant, dry matter, umbellets and seeds/umbel were obtained under this treatment. It provided the seed and straw yields of 1.36 and 2.56 t/ha, respectively, indicating an increase of 162.5 and 116.9% than unweeded control. It also recorded the highest harvest index (35.01%) and lowest weed competition index (0.73%) among all the treatments. Providing seed yields of 1.20 and 1.17 t/ha with weed competition indices of 12.3 and 14.4%, 1 hand-weeding at 20 days after sowing and pendimethalin at 1.0 kg/ha were the next better and statistically similar treatments. The highest net returns ( 55,841/ha) and benefit: cost ratio (2.39) were obtained with 2 hand-weedings at 20 and 40 days after sowing treatment. Pendimethalin at 1.0 kg/ha + hand-weeding at 40 days after sowing was found at par with hand-weeding twice fetching net returns of 54,308 and benefit: cost ratio of 2.3. Application of 75 kg N/ha significantly increased the growth and yield of coriander over preceding levels. It enhanced the seed yield of coriander to the extent of 11.9, 32.7 and 84.3% over 50 and 25 kg N/ha and control respectively. This level of N also maximized the net returns ( 54,412/ha) and benefit: cost ratio (2.35).