Study on the fertilizer efficiency and the economic benefit of new slow-release nitrogenous fertilizers

A pot experiment was conducted to study effects of two kinds of slow-release nitrogen fertilizer made by ourselves on the spinach and cherry radish.Through the study of vegetable yields,N utilization ratio and Nitrate content,the results indicated that the best fertilizer effect and most cost-effective was the slow-release nitrogen fertilizer Ⅰ.In different levels of nitrogen,with the increase of fertilizer,vegetable yields showed a trend that increased at the beginning and then decreased,when the fertilization was up to 0.33 g/2.5kg,vegetable yields reached the maximum,which accorded with the reward degression rate of fertilizer.By comparing with different nitrogen fertilizer,it showed that vegetable yields which were used slow-release nitrogen fertilizer were higher than carbamide,and yields of the slow-release nitrogen fertilizer Ⅰ were higher than the slow-release nitrogen fertilizer Ⅱ.With increasing fertilization,nitrogen fertilizer utilization gradually decreased.The better practical effect was slow-release nitrogen fertilizer,and N utilization ratio was higher than carbamide.The utilization of nitrogen fertilizer was quite high in the second crops too.The more fertilization was,the more nitrate content was,and the economic benefit of the slow-release nitrogen fertilizerⅠ was highest in 0.33 g/2.5kg level.