Effect of vegetable soybean decomposition on quantity of N-uptake and yield of Chinese kale

Abstract

The objective of this research was aimed to evaluate the availability of mineralized N from vegetable soybean for Chinese kale growth by using 15N technique and to find out the suitable rate of soybean biomass to be used as fertilizer for Chinese kale. Experiment 1 was conducted at the farmer’s plot in Chiang Rai province during September to November 2005 and the experiment 2, was conducted in the experimental plot of the Faculty of Agriculture Chiang Mai University during January 2006 to June 2006. Soybean decomposed in 2 weeks and had everage of 11.82 kgN/rai and slightly reduced until 0.28 kgN/rai in 6 weeks. Growth of Chinese kale after soybean green manure application in 4 weeks, indicated that fresh weight had non significant difference. Yield of Chinese kale had everage between 995.10 to 1,345.79 kg/rai in 6 weeks and the highest yield was found in treatment that was incorporated with biomass 2.4 t/rai which gave yield of 1,345.79 kg/rai. Estimation of 15N recoveries from soybean to Chinese kale for all treatments were averaged about 30.36% or 11.87 kgN/rai. Yield of Chinese kale from treatment that used 21.1 kgN/rai had highest yield of 1,645.47 kg/rai which were not significantly difference from the treatment that incorporated soybean biomass with root at the rate of 6,474 kg/rai which gave yield of 1,532.20 kg/rai.