小麦秸秆还田后茬棉田土壤NO_(3)^(−)-N和酚酸变化对棉苗根系生长的影响  

Effects of content dynamics of NO_(3)^(-)-N and phenolic acids in soil on root growth of cotton seedlings under the return of wheat straw

作　　者：李佳男 杨长琴[2] 束红梅[2] 张国伟[2] 王晓婧 刘瑞显[2] 陈嘉敏 王飞兵 陈新红 LI Jianan;YANG Changqin;SHU Hongmei;ZHANG Guowei;WANG Xiaojing;LIU Ruixian;CHEN Jiamin;WANG Feibing;CHEN Xinhong(College of Life Sciences and Food Engineering,Huaiyin Institute of Technology,Huai’an 223003,China;Institute of Industrial Crops,Jiangsu Academy of Agricultural Sciences/Key Laboratory of Cotton and Rapeseed in the Lower Reaches of the Yangtze River,Ministry of Agriculture,Nanjing 210014,China)

机构地区：[1]淮阴工学院生命科学与食品工程学院,淮安223003 [2]江苏省农业科学院经济作物研究所/农业部长江下游棉花与油菜重点实验室,南京210014

出　　处：《中国生态农业学报（中英文）》2023年第6期868-876,共9页Chinese Journal of Eco-Agriculture

基　　金：国家自然科学基金面上项目(32071968);江苏省农业科技自主创新资金项目[CX(22)2015]资助。

摘　　要：揭示前茬小麦长期秸秆还田后,后茬棉田土壤硝态氮(NO_(3)^(-)-N)与酚酸含量的时空变化对棉苗根系生长影响的生理机制,可为完善秸秆还田技术提供理论支撑。试验于2021年与2022年在小麦长期秸秆定位还田地块进行。以棉花品种‘中棉所425’为材料,设置小麦秸秆不还田(CK)与小麦秸秆还田(S)2个处理。结果表明,秸秆还田增加了土壤NO_(3)^(-)-N与酚酸含量,对0~20 cm土层的影响大于20~40 cm;随秸秆还田后时间推移,土壤NO_(3)^(-)-N与酚酸含量呈先增加后降低趋势,且在秸秆还田后24~31 d达到峰值。秸秆还田后31 d前,秸秆还田处理棉株根系活力、根系NO_(3)^(-)-N含量、硝酸还原酶活性、根系生物量和形态指标均显著低于CK处理,31 d后则呈相反趋势。相关分析表明,0~20 cm土壤酚酸含量与根系活力、根系NO_(3)^(-)-N含量、棉花根系长度、直径、表面积和地上部生物量呈显著负相关;不同土层NO_(3)^(-)-N含量与棉苗形态、生理指标及生物量之间呈正相关但未达显著水平。秸秆还田对棉花幼苗生长影响呈“先抑后促”的趋势,秸秆还田后31 d内,酚酸含量的增加降低了棉苗根系活力,阻碍了根系生长,抑制了棉苗对NO_(3)^(-)-N的吸收利用,表明秸秆还田前期对棉株生长的“抑制效应”大于秸秆的“肥料效应”,秸秆还田31 d后,秸秆的“肥料效应”大于酚酸的“抑制效应”,促进棉株根系的生长。Nitrate nitrogen(NO_(3)^(-)-N)is the main form of nitrogen released from crop straws under dry farming conditions,and is the main form of nitrogen absorption by the roots and the plant root growth regulatory signal of cotton.Straw return affects the availability of soil and fertilizer N,thus inhibiting the early growth of crops and even decreasing crop yields.The straw return also releases many phenolic acids,inhibiting crop seed germination and root growth.This study aimed to reveal the mechanisms by which the contents dynamics of NO_(3)^(-)-N and phenolic acid in the soil affect the growth of cotton seedlings under the return of wheat straw.Based on the 11-year return of wheat straw,field experiments were conducted in 2021 and 2022 at Jiangsu Academy of Agricultural Sciences Experimental Station in Nanjing,Jiangsu Province,China.Two treatments,wheat straw removal(CK)and wheat straw return(S),were applied.The contents of NO_(3)^(-)-N and phenolic acid in the soil of the subsequent cotton field,the NO_(3)^(-)-N content and nitrate reductase activity of cotton seedlings,the activity and morphology indices of cotton roots,and the biomass of cotton seedlings were investigated.The results demonstrated that straw return increased the contents of NO_(3)^(-)-N and phenolic acid in the soil,and the effect on the 0–20 cm soil layer was greater than that on the 20–40 cm soil layer.With a delay of days after the straw return,the contents of NO_(3)^(-)-N and phenolic acid in the soil increased and then decreased,reaching a peak at 24-31 d after the straw return.Within 31 days of straw return,the root activity,root NO_(3)^(-)-N content,nitrate reductase(NR)activity,root biomass,and morphological indices of cotton seedlings under the straw return treatment were significantly lower than those under the CK treatment but showed the opposite trend after 31 d of straw return.The correlation analysis showed that phenolic acid content in 0–20 cm soil were significantly and negatively correlated with the root activity,NO_(3)^(-)

关 键 词：小麦秸秆还田 NO_(3)^(-)-N 酚酸 根系活力 硝酸还原酶 后茬棉花 

分 类 号：S562.01[农业科学—作物学]