Study on Plant Available Nitrogen Release in the soils Applying Different Organic Fertilizers

Abstract

The organic fertilizer is the main source of plant nutrients for organic farming under the variation of plant nutrients content which involve to the source and raw materials, which affects to the release ability and amount of plant available nutrients. The objective of the study was to determine the effect of soils with organic fertilizers to the amount and release rate of plant available N. It was studied under greenhouse experiment by Ruzi grass continuous planting, at Faculty of Agricultural Production, Maejo University. The 4x4 factorial in randomized complete block design (RCBD) and 3 replications was used. The main factors consists of the 4 soils (Mae Tang: Mt, Hang Dong: Hd, San Sai: Sai and Mae Rim: Mr soils) and 3 organic fertilizers (compost, manure and earthworm vermicompost) 2 ton.rai-1. Estimating the accumulation of plant available N and release rate during 1 year, by determining the N uptake of Ruzi grass at 30, 60, 90, 150, 240 and 360 days after planting. The data was fitted using simple linear regression to estimate the release rate of plant available N. The results showed that the plant available N and release rate were significantly highest in Mt and Hd soil with compost (769 and 768 mg kg-1), and release rate of plant available N were 2.04 and 2.10 mg kg-1 day-1. The amount of plant available nitrogen and release rates showed the significant correlation with organic matter of organic fertilizers. The coefficient of determination (Adj. R2) were 0.885 for amount of plant available N, and 0.897 for release rate at P<0.01.