聚天门冬氨酸/盐对水稻田面水氮素变化及养分利用的影响

为探究聚天门冬氨酸/盐(PASP)对稻田氮素流失及水稻养分利用的调控作用,本研究以普通聚天门冬氨酸钙/锌盐和改性聚天门冬氨酸钙/锌盐为供试材料,在干旱棚条件下,通过水稻桶栽试验研究了PASP对水稻田面水氮浓度变化和水稻生长、氮磷钾养分吸收及土壤养分的影响。结果表明,与常规尿素对照处理相比,各聚天门冬氨酸/盐处理降低了田面水氮素浓度,尤其在施肥后第3 d和第5 d,铵态氮和硝态氮浓度显著降低了16.8%～44.7%和20.4%～42.8%。聚天门冬氨酸/盐的施用有利于水稻生长及产量提高,水稻株高、有效穗数、秸秆产量和籽粒产量以及氮、磷、钾养分吸收量均表现出增加趋势,其中改性聚天门冬氨酸钙盐处理显著增加了水稻株高(12.0%)、有效穗数(13.8%)、秸秆产量(9.26%)及籽粒氮含量(8.32%),氮肥表观利用率提高了8.4%,但差异不显著。聚天门冬氨酸/盐处理土壤氮含量也有所增加,尤其是NH4+-N含量显著增加,但土壤有效磷和速效钾含量受影响不大。综合水稻产量、养分吸收利用以及田面水氮素流失风险,改性聚天门冬氨酸/盐处理效果优于普通聚天门冬氨酸/盐,且改性聚天门冬氨酸钙盐处理最好。田间应用效果有待进一步验证。

Effects of polyaspartic-acid/salt on nitrogen loss from paddy surface water and nutrients utilization

To investigate the effects of polyaspartic-acid/salt (PASP) on paddy nitrogen (N) loss and nutrients utilization, PASP-Ca/Zn and modified PASP-Ca/Zn were used for pot experiments conducted in a rainproof tank. We evaluated the impacts of PASP on N concentrations in surface water, rice growth and its N, P, K uptake, and soil nutrients. The results showed that PASP treatments decreased NH₄⁺-N, NO₃^--N, and TN concentrations of surface water, with 16.8%~44.7% lower NH₄⁺-N and 20.4%~42.8% lower NO₃^--N in PASP than the control in day 3 d and 5 d after fertilization, respectively. Addition of PASP promoted rice growth and yield; modified PASP-Ca/Zn significantly increased rice height (12.0%), productive tillers (13.8%), straw yield (9.26%), and grain N concentration (8.32%), with 8.4% higher N use efficiency. NH₄⁺-N concentrations in paddy soil were significantly increased by 28.4%~62.2% in PASP treatments compared to the control, whereas no significant difference in soil available P and K was observed. Considering rice yield, nutrients utilization, and N loss risk of surface water, modified PASP-Ca/Zn was more effective than PASP-Ca/Zn. In this study, modified PASP-Ca treatment was evaluated to be the best, with grain yield 9.21% greater and NH₄⁺-N of the surface water 44.7% lower than the control. However, PASP application effects need to be verified further by field experiments.