李佳男, 杨长琴, 束红梅, 张国伟, 王晓婧, 刘瑞显, 陈嘉敏, 王飞兵, 陈新红. 小麦秸秆还田后茬棉田土壤NO3-N和酚酸变化对棉苗根系生长的影响[J]. 中国生态农业学报 (中英文), 2023, 31(6): 868−876. DOI: 10.12357/cjea.20220918
引用本文: 李佳男, 杨长琴, 束红梅, 张国伟, 王晓婧, 刘瑞显, 陈嘉敏, 王飞兵, 陈新红. 小麦秸秆还田后茬棉田土壤NO3-N和酚酸变化对棉苗根系生长的影响[J]. 中国生态农业学报 (中英文), 2023, 31(6): 868−876. DOI: 10.12357/cjea.20220918
LI J N, YANG C Q, SHU H M, ZHANG G W, WANG X J, LIU R X, CHEN J M, WANG F B, CHEN X H. Effects of content dynamics of NO3-N and phenolic acids in soil on root growth of cotton seedlings under the return of wheat straw[J]. Chinese Journal of Eco-Agriculture, 2023, 31(6): 868−876. DOI: 10.12357/cjea.20220918
Citation: LI J N, YANG C Q, SHU H M, ZHANG G W, WANG X J, LIU R X, CHEN J M, WANG F B, CHEN X H. Effects of content dynamics of NO3-N and phenolic acids in soil on root growth of cotton seedlings under the return of wheat straw[J]. Chinese Journal of Eco-Agriculture, 2023, 31(6): 868−876. DOI: 10.12357/cjea.20220918

小麦秸秆还田后茬棉田土壤NO3-N和酚酸变化对棉苗根系生长的影响

Effects of content dynamics of NO3-N and phenolic acids in soil on root growth of cotton seedlings under the return of wheat straw

  • 摘要: 揭示前茬小麦长期秸秆还田后, 后茬棉田土壤硝态氮(NO3-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NO3-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NO3-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NO3-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NO3-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NO3-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NO3-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。

     

    Abstract: Nitrate nitrogen (NO3-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 NO3-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 NO3-N and phenolic acid in the soil of the subsequent cotton field, the NO3-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 NO3-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 NO3-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 NO3-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, NO3-N content, length, diameter, and surface area of the root, and the aboveground biomass of cotton seedlings. The NO3-N content in different soil layers was positively correlated with the index of morphology and physiology and the biomass of cotton seedlings but did not reach a significant level. The effect of straw return on the growth of cotton seedlings showed a trend of “first inhibition and then promotion”. Within 31 d after straw return, the “inhibition effect” of phenolic acid in soil on the growth of cotton seedlings was greater than that of the “fertilization effect” of straw. Higher phenolic acid content reduced the root activity and root growth of cotton seedlings, inhibiting the absorption and utilization of NO3-N in cotton seedlings. After 31 d of straw return, the “fertilization” effect of straw was greater than the “inhibition” effect of phenolic acid, promoting the root growth of cotton seedlings.

     

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