Abstract:

This study focuses on the characteristics of the movement, transformation and leaching of different nitrogen forms in soil by dripping and pouring fertigation with fertilizer gradients by determining the nitrogen content of soil solution in a Red Fuji apple orchard in Weibei dry plateau. The results showed that different application methods of fertilization were the key factor to affect the movement, accumulation and transformation of different nitrogen forms in soil. The dripping fertigation decreased significantly the nitrogen movement, accumulation and transformation compared with pouring fertigation. The urea-N was main form of N leached, followed by NO₃^--N, and then NH₄⁺-N leached. Neither dripping nor pouring had obvious effect on nitrogen loss when the fertilizer concentration was 0.32 kg·tree^-1. However the nitrogen movement, accumulation and transformation was significantly higher with pouring fertigation than with the dripping fertigation when the fertilizer application amounts were added to 1.2 kg·tree^-1, especially in the 40-80 cm soil layers. By comprehensive comparing and analyses, dripping fertigation significantly decreased the leaching loss of different nitrogen forms in soil, and increased nitrogen content, especially available N in soil. The nitrogen loss will be decreased when fertilizer application is 0.64-1.2 kg·tree^-1 in the whole year.

Key words: apple, dripping fertigation, nitrogen migration, soil solution