EFFECTS OF NITROGEN APPLICATION ON BIOMASS ACCUMULATION, REMOBILIZATION, AND SOIL WATER CONTENTS IN A RAINFED WHEAT FIELD

Authors : Wenxue DUAN, Zhenwen Yu, Yongli ZHANG, Dong WANG, Yu SHİ, Zhenzhu Xu

Pages : 25-34

Doi:10.17557/tjfc.45522

View : 24 | Download : 17

Publication Date : 2014-01-01

Article Type : Research Paper

Abstract :This study examined the effects of different levels of N fertilization on dry matter accumulation and remobilization, and soil water contents in a rainfed winter wheat field. The experiments were carried out during growth seasons in 2009 – 2012 in a hilly region in Shandong Province, China. The N rates applied were 0 insert ignore into journalissuearticles values(N0, the control);, 90 insert ignore into journalissuearticles values(N1);, 120 insert ignore into journalissuearticles values(N2);, 150 insert ignore into journalissuearticles values(N3);, 180 insert ignore into journalissuearticles values(N4);, and 210 insert ignore into journalissuearticles values(N5); kg N ha1. Our results showed that N fertilization significantly increased dry matter accumulation and post-anthesis assimilates compared with controls. At anthesis, total above-ground biomass increased significantly with increasing N rate up to 150 kg ha1 and then leveled off in the 2009 – 2010 and 2011 – 2012 growth seasons. However, the biomass in the 2010 – 2011 growth season did not vary with different N rates. At maturity, the accumulation of dry matter in vegetative organs significantly increased with increasing N rate up to 150 kg ha1 and then leveled off in all growth seasons. Of all the treatments, N3 and N4 had relatively higher total above-ground biomass at maturity. In contrast, dry matter remobilization efficiency showed a declining trend under increasing N rate. The higher post-anthesis assimilates and the contribution of pre-anthesis assimilates to grains were obtained at N rates of 150 and 180 kg ha1 in all growth seasons. Soil water contents in 0 – 120, 0 – 100, and 40 – 160 cm soil layers during each growth season decreased significantly with increasing N rate up to 150 kg ha1. The maximum grain yields were obtained under N rate of 150 kg ha1 in all growth seasons, with the highest grain yield being 7160.8 kg ha1 in the 2011 – 2012 growth season. Our results suggested that N fertilization at 150 kg N ha1 was optimal for grain production via promoting above-ground biomass and soil water consumption in deep soil layers. These results should help provide guidance for N fertilization management for optimal and sustainable wheat production in the said region
Keywords : Dry matter accumulation, dry matter remobilization, grain yield, N application rate, rainfed winter wheat, soil water content