{"title":"不同季节覆盖作物系统中水分供应和氮循环的变化","authors":"","doi":"10.1016/j.fcr.2024.109608","DOIUrl":null,"url":null,"abstract":"<div><h3>Context</h3><div>Cover crops (CCs) exert significant influences on both soil water content (SWC) and nitrogen (N) cycling, with their effects often varying across different stages of crop succession. Many research endeavors overlook this seasonal variability by focusing solely on single sampling time points.</div></div><div><h3>Objective</h3><div>This study seeks to explore how the introduction of diverse CCs influences the seasonal fluctuations of soil nitrate nitrogen (NO<sub>3</sub>-N) and biological (soil N functional genes – NFGs) components of the N cycle, SWC, and cash crop yield over a three-year maize-soybean succession in northeastern Italy.</div></div><div><h3>Methods</h3><div>Three CC management systems were compared: a fixed treatment with triticale; a 3-year succession of rye, crimson clover, and mustard; and a weedy fallow as control. Soil N cycling was assessed using real-time PCR and Ion Chromatography, SWC through Sentek’s Diviner2000.</div></div><div><h3>Results</h3><div>CCs had no impact on cash crop yields and did not display water competition with subsequent cash crops compared to the weedy fallow. At CCs termination, grasses decreased soil NO<sub>3</sub>-N content (as catch crops) while enhancing potential microbial N-fixing activity (<em>nifH</em>), whereas clover led to the highest residual NO<sub>3</sub>-N and potential N nitrification (AOA). Agronomic operations likely mitigated differences in NFG abundances following CC residue incorporation. During the cash crop season, clover, mustard, and weeds (including wild legumes) were estimated to release higher amounts of N according to the CC-NCALC model, compared to rye and triticale which exhibited immobilization. Nonetheless, consistent N nitrification and denitrification potentials were observed across all treatments except for weedy fallow, with higher NFG abundance when soybean was cultivated instead of maize, underscoring the influence of cash crop species on N transformation dynamics.</div></div><div><h3>Conclusions</h3><div>CC and cash crop species, seasonality of crops sequence, and management operations represent pivotal factors shaping the soil N cycling dynamics intricately governed by N-cycling microbial communities and the temporal variability of the SWC. Upon CC termination, grass CCs decrease soil NO<sub>3</sub>-N content, whereas clover CC sustain high NO<sub>3</sub>-N content, enhancing microbial nitrification. Agronomic operations disrupt differences in N processes subsequent to the incorporation of different CCs. However, all CC residues enhance microbe-mediated nitrification and denitrification by cash crop harvest time, potentially more pronounced in the presence of soybean cash crop compared to maize.</div></div><div><h3>Significance</h3><div>The substantial seasonal variability observed emphasizes the necessity of carefully timing sample collection within a crop succession (e.g., at CC termination) for effectively utilizing NFGs and chemical indicators to assess the impacts of CCs on N dynamics.</div></div>","PeriodicalId":12143,"journal":{"name":"Field Crops Research","volume":null,"pages":null},"PeriodicalIF":5.6000,"publicationDate":"2024-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Variations in water availability and N cycling across different seasons in cover crop systems\",\"authors\":\"\",\"doi\":\"10.1016/j.fcr.2024.109608\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><h3>Context</h3><div>Cover crops (CCs) exert significant influences on both soil water content (SWC) and nitrogen (N) cycling, with their effects often varying across different stages of crop succession. Many research endeavors overlook this seasonal variability by focusing solely on single sampling time points.</div></div><div><h3>Objective</h3><div>This study seeks to explore how the introduction of diverse CCs influences the seasonal fluctuations of soil nitrate nitrogen (NO<sub>3</sub>-N) and biological (soil N functional genes – NFGs) components of the N cycle, SWC, and cash crop yield over a three-year maize-soybean succession in northeastern Italy.</div></div><div><h3>Methods</h3><div>Three CC management systems were compared: a fixed treatment with triticale; a 3-year succession of rye, crimson clover, and mustard; and a weedy fallow as control. Soil N cycling was assessed using real-time PCR and Ion Chromatography, SWC through Sentek’s Diviner2000.</div></div><div><h3>Results</h3><div>CCs had no impact on cash crop yields and did not display water competition with subsequent cash crops compared to the weedy fallow. At CCs termination, grasses decreased soil NO<sub>3</sub>-N content (as catch crops) while enhancing potential microbial N-fixing activity (<em>nifH</em>), whereas clover led to the highest residual NO<sub>3</sub>-N and potential N nitrification (AOA). Agronomic operations likely mitigated differences in NFG abundances following CC residue incorporation. During the cash crop season, clover, mustard, and weeds (including wild legumes) were estimated to release higher amounts of N according to the CC-NCALC model, compared to rye and triticale which exhibited immobilization. Nonetheless, consistent N nitrification and denitrification potentials were observed across all treatments except for weedy fallow, with higher NFG abundance when soybean was cultivated instead of maize, underscoring the influence of cash crop species on N transformation dynamics.</div></div><div><h3>Conclusions</h3><div>CC and cash crop species, seasonality of crops sequence, and management operations represent pivotal factors shaping the soil N cycling dynamics intricately governed by N-cycling microbial communities and the temporal variability of the SWC. Upon CC termination, grass CCs decrease soil NO<sub>3</sub>-N content, whereas clover CC sustain high NO<sub>3</sub>-N content, enhancing microbial nitrification. Agronomic operations disrupt differences in N processes subsequent to the incorporation of different CCs. However, all CC residues enhance microbe-mediated nitrification and denitrification by cash crop harvest time, potentially more pronounced in the presence of soybean cash crop compared to maize.</div></div><div><h3>Significance</h3><div>The substantial seasonal variability observed emphasizes the necessity of carefully timing sample collection within a crop succession (e.g., at CC termination) for effectively utilizing NFGs and chemical indicators to assess the impacts of CCs on N dynamics.</div></div>\",\"PeriodicalId\":12143,\"journal\":{\"name\":\"Field Crops Research\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":5.6000,\"publicationDate\":\"2024-10-21\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Field Crops Research\",\"FirstCategoryId\":\"97\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S0378429024003617\",\"RegionNum\":1,\"RegionCategory\":\"农林科学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q1\",\"JCRName\":\"AGRONOMY\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Field Crops Research","FirstCategoryId":"97","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0378429024003617","RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"AGRONOMY","Score":null,"Total":0}
引用次数: 0
摘要
背景覆盖作物(CCs)对土壤含水量(SWC)和氮(N)循环都有显著影响,其效果往往在作物演替的不同阶段各不相同。本研究旨在探索在意大利东北部玉米-大豆三年连作期间,引入不同的覆盖作物如何影响土壤硝态氮(NO3-N)和氮循环的生物(土壤氮功能基因)成分、SWC 和经济作物产量的季节性波动。方法比较了三种 CC 管理系统:三叶草的固定处理;黑麦、深红三叶草和芥菜的三年连作;以及作为对照的杂草休耕。结果与杂草休耕相比,CCs 对经济作物产量没有影响,也没有出现与后续经济作物争水的现象。在 CCs 终止时,禾本科植物降低了土壤中的 NO3-N 含量(与捕获作物一样),同时提高了潜在的微生物固氮活性(nifH),而三叶草则导致了最高的 NO3-N 残留量和潜在的氮硝化(AOA)。农艺操作可能减轻了掺入 CC 残留物后 NFG 丰度的差异。在经济作物季节,根据 CC-NCALC 模型估计,三叶草、芥菜和杂草(包括野生豆科植物)释放的氮量较高,而黑麦和三粒豆则表现出固定作用。尽管如此,除杂草休耕外,所有处理的氮硝化和反硝化潜力都是一致的,当种植大豆而不是玉米时,NFG 丰度更高,这突出表明了经济作物物种对氮转化动态的影响。CC终止时,禾本科CC会降低土壤中的NO3-N含量,而苜蓿CC则会维持较高的NO3-N含量,从而提高微生物的硝化作用。农艺操作扰乱了不同 CC 加入后氮过程的差异。意义:观察到的巨大季节性变化强调了在作物连作过程中(如在CC终止时)仔细选择样本采集时间的必要性,以便有效利用NFGs和化学指标来评估CCs对氮动态的影响。
Variations in water availability and N cycling across different seasons in cover crop systems
Context
Cover crops (CCs) exert significant influences on both soil water content (SWC) and nitrogen (N) cycling, with their effects often varying across different stages of crop succession. Many research endeavors overlook this seasonal variability by focusing solely on single sampling time points.
Objective
This study seeks to explore how the introduction of diverse CCs influences the seasonal fluctuations of soil nitrate nitrogen (NO3-N) and biological (soil N functional genes – NFGs) components of the N cycle, SWC, and cash crop yield over a three-year maize-soybean succession in northeastern Italy.
Methods
Three CC management systems were compared: a fixed treatment with triticale; a 3-year succession of rye, crimson clover, and mustard; and a weedy fallow as control. Soil N cycling was assessed using real-time PCR and Ion Chromatography, SWC through Sentek’s Diviner2000.
Results
CCs had no impact on cash crop yields and did not display water competition with subsequent cash crops compared to the weedy fallow. At CCs termination, grasses decreased soil NO3-N content (as catch crops) while enhancing potential microbial N-fixing activity (nifH), whereas clover led to the highest residual NO3-N and potential N nitrification (AOA). Agronomic operations likely mitigated differences in NFG abundances following CC residue incorporation. During the cash crop season, clover, mustard, and weeds (including wild legumes) were estimated to release higher amounts of N according to the CC-NCALC model, compared to rye and triticale which exhibited immobilization. Nonetheless, consistent N nitrification and denitrification potentials were observed across all treatments except for weedy fallow, with higher NFG abundance when soybean was cultivated instead of maize, underscoring the influence of cash crop species on N transformation dynamics.
Conclusions
CC and cash crop species, seasonality of crops sequence, and management operations represent pivotal factors shaping the soil N cycling dynamics intricately governed by N-cycling microbial communities and the temporal variability of the SWC. Upon CC termination, grass CCs decrease soil NO3-N content, whereas clover CC sustain high NO3-N content, enhancing microbial nitrification. Agronomic operations disrupt differences in N processes subsequent to the incorporation of different CCs. However, all CC residues enhance microbe-mediated nitrification and denitrification by cash crop harvest time, potentially more pronounced in the presence of soybean cash crop compared to maize.
Significance
The substantial seasonal variability observed emphasizes the necessity of carefully timing sample collection within a crop succession (e.g., at CC termination) for effectively utilizing NFGs and chemical indicators to assess the impacts of CCs on N dynamics.
期刊介绍:
Field Crops Research is an international journal publishing scientific articles on:
√ experimental and modelling research at field, farm and landscape levels
on temperate and tropical crops and cropping systems,
with a focus on crop ecology and physiology, agronomy, and plant genetics and breeding.