Application Schedule of N-P-K in Drip Fertigation Affects Abscission of Cotton Bolls

DENG Zhong; ZHAI Guoliang; WANG Xiaosen; ZONG Jie; FENG Junjie; CAI Jiumao; LYU Mouchao

doi:10.13522/j.cnki.ggps.2017.08.001

Abstract：This paper presents the results of a field experiment aiming to investigate the impact of different drip fertigation schedules on abscission of cotton bolls.We considered three irrigation amounts,3 300,3 900 and 4 500 m3/hm2,and four N application rates,150,225,300,375 kg/hm2.The N was either applied with P-K as topdressing fertilizer,or applied as topdressing with the drip irrigation while the P-K were used as base fertilizer.The results showed that the boll abscission increased first,peaking at the boll setting stage,and then decreased rapidly at the flowering stage under both N application methods.The abscission rate atirrigation of 3 900 m3/hm2 was the lowest in comparison with others.When the N application was 150 kg/hm2,the abscission rate of the cotton buds and bolls increased significantly under different N applications.The abscission was the lowest when N application was 300 kg/hm2,increasing when the irrigation amount and nitrogen application were either too low or too high.When N was applied with P-K as topdressing fertilizer at the rate of 291.25 kg/hm2 and the irrigation amount was 3 890.46 m3/hm2,the boll abscission was 53.60％,while trnder the same water and N applications,applying N-P-K as topdressing with the drip irrigation decreased the abscission by 49.12％.In summary,applying N with P-K as topdressing was more efficient in reducing the abscission compared with applying N together with the drip irrigation by using P-K as base fertilizer.