Fertilization Effect on N Distribution in Cotton Plant

摘要

Nitrogen (N) (300 kg/ha) is normally applied to cotton crops in three splits: pre-plant application (PPA, 30%), first bloom application (FBA, 40%) and peak bloom application (PBA, 30%) in Yangtze River Valley China. However, fixing the FBA ratio (40%) of a lower (than conventional) N rate (225 kg N/ha) and allocating more N from PPA to PBA harvested the same yield as the conventional in field. Such a split ratio should have utilized the N more efficiently by partitioning it to the fruiting plant parts. The aim of this research was to determine where fertilizer N is distributed in cotton plants as affected by N fertilization. A pot trial was carried out to study the effects of N split ratio balance between PPA and PBA on cotton yield, biomass, N absorption and distribution. The present results, concerning N distribution, showed that treatment A (0%PPA, 60%PBA) had a higher ratio of 15N to total N (57%) in the plant, and higher proportion of 15N accumulated in fruiting and relative parts (79%) than any other treatments. It was suggested that allocating more N for PBA ensure more N to be used in fruiting and relative parts. Thus N fertilization in the peakdemand period should benefit the improvement in N distribution.