Interactive Effects of Senna Stems and Nitrogen Fertilization on Net Photosynthesis, Carbohydrate and Nitrogen Metabolism and Yield of Wheat

摘要

A field trial was undertaken to study the interactive effects of senna stems (0, 2.5 and 5.0 t ha~(-1)) and nitrogen (0, 50 and 100 kg ha~(-1)) on wheat (Triticum aestivum L. cv. Raj. 3077) during rabi season of 2003-04. Senna stems and nitrogen application, either alone or in combination significantly increased leaf area, net photosynthetic rate, levels of total chlorophyll, starch, reducing sugars, soluble protein, free amino acids and nitrate reductase activity at vegetative, flowering and grain development stages. Combined application of senna stems at the rate of 5.0 t ha~(-1) and nitrogen at the rate of 50 kg ha~(-1) was most beneficial for enhancement of various leaf metabolites, net photosynthesis and NR activity at all the growth stages, but promotive effects were more pronounced at the vegetative stage followed by flowering stage. Application of senna stems significantly increased grain yield (25.9% increase at 5.0 t ha~(-1) over control) and dry matter production (29.2% increase at 5.0 tha~(-1) over control) of wheat. Nitrogen application also increased grain yield by 41.4% and 58.0% at 50 and 100 kg ha~(-1) levels, respectively. However, application of senna stems and N fertilization showed additive effects. It was found that 5.0 t ha~(-1) senna stems in combination with 50 kg ha~(-1) N enhanced grain yield by 76.1% and DMP by 71.0% over control. These results indicate that fertilizer N requirement may be significantly reduced by senna stems application to achieve similar levels of grain yield as achieved with 100 kg ha~(-1) nitrogen.