Abstract:

In order to improve the use effect of ordinary stable urea fertilizer,develop biostimulant and biochemical inhibitor combined high-efficiency,stable and synergistic urea fertilizer.A field pot test was carried out to investigate the effect of urea fertilizer with the biological stimulator Enteromorpha polysaccharide and various biological inhibitors on rice cultivation in black soil.The control group in the experiment consisted of no nitrogen fertilizer (CK) and only urea fertilizer(N).In the treatment group, urea was supplemented with Enteromorpha polysaccharide (E), the biochemical inhibitor N-butyl thiophosphate triamine (NBPT), 3,4-dimethylpyrazole phosphate (DMPP), and 2-chloro-6-trimethylpyridine (CP). Additionally, a combination of Enteromorpha polysaccharide and a biochemical inhibitor was also added to urea. Nine treatments were set up to study the nitrogen conversion characteristics,physiological and developmental biological indexes of rice,nitrogen uptake by plants,and efficiency of nitrogen absorption and utilization from fertilizers.When urea was applied alone,the addition of Enteromorpha polysaccharide reduced ammonia volatilization loss in black soil,significantly increased ammonium nitrogen content in soil at the tillering stage,promoted plant growth,and then significantly increased grain yield and nitrogen use efficiency.The combination of Enteromorpha polysaccharide and NBPT significantly increased ammonium nitrogen content in black soil,but the application of Enteromorpha polysaccharide promoted the decomposition of NBPT,resulting in no significant effect on rice yield and nitrogen use efficiency.In black soil cultivation rice,the combination of Enteromorpha prolifera polysaccharide and DMPP significantly reduced rice grain yield and nitrogen use efficiency,and the application of stable urea fertilizer combined with both was not conducive to yield increase and efficiency increase.The combination of tillering stage CP rice plants and Enteromorpha polysaccharides had the highest ammonium nitrogen content in black soil,and had a synergistic effect on the process of inhibiting urea nitrogen conversion to nitrate nitrogen.The apparent nitrification rate of black soil treated with the two was significantly lower than that of CP alone,while the increase in ammonium nitrogen promoted rice tillering,increased panicle percentage,and thus significantly increased rice grain yield.

Key words: Black soil, Rice, Biochemical inhibitor, Biostimulant, Enteromorpha polysaccharide, Grain yield