施石灰和秸秆还田对双季稻田土壤钾素表观平衡的互作效应

土壤酸化和钾素亏缺是制约南方酸性稻田生产力持续提升的重要因素。施石灰和秸秆还田分别是改良土壤酸化和补充钾素的有效措施,但二者对土壤钾素盈亏平衡的互作效应还不甚清楚。于2015—2018年,在江西省上高县开展施石灰和秸秆还田两因素田间定位试验,共设置4个处理:(1)秸秆不还田,不施石灰;(2)秸秆不还田,仅2015年施一次石灰;(3)每季秸秆全量还田,不施石灰;(4)每季秸秆全量还田,仅2015年施一次石灰。结果表明,秸秆还田显著提高了水稻钾素吸收,施石灰仅显著增加了2016年晚稻钾素吸收。施石灰和秸秆还田仅对2016年晚稻钾素吸收有显著正向互作效应。在秸秆还田下,施石灰使2016年晚稻钾素吸收增加了25.7%;而在秸秆不还田下无显著影响。试验进行4年后,施石灰和秸秆还田对土壤全钾含量无显著影响。但4年土壤钾素表观平衡估算表明,在秸秆还田下土壤总累积钾素表观平衡表现为盈余,秸秆不还田下则为亏缺,而施石灰对其无显著影响。施石灰和秸秆还田对土壤总累积钾素表观平衡有显著的互作效应。在施石灰和不施石灰条件下,秸秆还田分别使土壤累积钾素平均表观盈余19.5 kg hm^–2 a...

Interactive effects of liming and straw return on apparent soil potassium ba-lance in a double rice cropping system

Soil acidification and potassium(K)deficit are two important factors limiting crop productivity in acidic paddy soils.Lime application and straw return are effective measures to alleviate soil acidification and improve soil K content,but their inter-action effect on K balance is still unclear.A four-year field experiment including two factors(liming and straw return)was conducted in Shanggao,Jiangxi province from 2015 to 2018.Four treatments were arranged in this experiment:(1)Straw removal without liming;(2)Straw removal with lime application only once in 2015;(3)100%straw return every season without liming;(4)Straw return combined with lime application only once in 2015.Straw return significantly improved rice K uptake,while liming only significantly increased K uptake in late rice in 2016.There were positive interactive effects between liming and straw return on K uptake in late rice in 2016.Liming significantly improved K uptake by 25.7%under straw return in late rice in 2016,but there was no significant effect under straw removal.Neither liming nor straw return significantly affected soil total K concentra-tion.However,the apparent balance of soil K in four years indicated the apparent balance of soil total K was surplus under straw return,while it was deficit under straw removal not returning,and lime application had not significant effect on it.Straw return enhanced soil cumulative apparent K surplus by 19.5 kg hm^-2a^-1 and 29.0 kg hm^-2a^-1 with liming and without liming,respec-tively.Soil cumulative apparent K balance showed a surplus of 24.3 kg hm^-2a^-1 under straw return and a deficit of 185.8 kg hm^-2a^-1 under straw removal.In summary,lime application combined with straw return could simultaneously alleviate soil acidification and maintain K balance,which is conductive to continuously improve the productivity of double rice cropping in acidic paddy fields.