Cover crops (CCs) and tillage practices influence C and N pools in soil, which can affect dissolved organic C (DOC) and N leaching from agricultural fields. Previous studies on cover crops have focused mostly on nitrate leaching and total C (TC). Therefore, a study was conducted in southern Illinois from 2015 to 2018 to evaluate the effects of tillage systems (conventional till [CT] and no‐tillage [NT]) and CCs on C and N pools including water‐extractable C (WEC), permanganate oxidizable C (POXC), TC, water‐extractable N (WEN), and total N (TN) in soil and on TN and DOC leaching collected with zero‐tension lysimeters. Crop rotations included were corn (Zea mays L.)–soybean [Glycine max (L.) Merr.] rotation without winter CC (C–S), corn–cereal rye (Secale cereale L.)–soybean–hairy vetch (Vicia villosa Roth) (C–R–S–HV), corn–cereal rye–soybean–oat + radish (Avena sativa L.+ Raphanus sativus L.) (C–R–S–OR). The WEC decreased over time under CT system at a depth to 0–15 cm in rotation C–R–S–OR having cereal rye and oat + radish CCs. The POXC at depths of 15–30 and 30–45 cm increased significantly over time from fall 2015 to spring 2018 for all rotations under both tillage systems. The cumulative DOC leaching was greater in C–R–S–HV rotation than in C–S rotation in fall 2015 and spring 2018. Inclusion of cereal rye in C–R–S–HV and C–R–S–OR rotations reduced cumulative TN leaching compared with the C–S having no CC in spring 2018. Increased DOC leaching losses with the introduction of CC should be addressed and need further evaluation for its impact on C cycling in surface and subsurface waters.

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覆盖作物和耕作对碳氮库的影响：蒸渗仪研究

覆盖作物（CCs）和耕作方式会影响土壤中的碳和氮库，这可能会影响农田中的溶解性有机碳（DOC）和氮的淋溶。以前对覆盖作物的研究主要集中在硝酸盐淋失和总碳（TC）上。因此，2015年至2018年在伊利诺伊州南部进行了一项研究，以评估耕作制度（常规耕作[CT]和免耕[NT]）和CCs对C和N池（包括可抽水C（WEC））的影响，高锰酸盐可氧化碳（POXC），TC，水可萃取氮（WEN）和土壤中总氮（TN）以及通过零张力渗漏仪收集的TN和DOC淋溶。轮作包括玉米（Zea mays L。）-大豆[ Glycine max（L.）Merr。]轮作，没有冬季CC（CS），玉米-谷物黑麦（Secale谷类）L.）–大豆– etch子（Vicia villosa Roth）（C–R–S–HV），玉米-谷物黑麦–大豆–燕麦+萝卜（Avena sativa L. + Raphanus sativusL.）（CR–S–OR）。在CT系统下，随着谷物黑麦和燕麦+萝卜CCs的旋转，CR-S-OR深度达到0-15 cm时，WEC随时间下降。从2015年秋季到2018年春季，两种耕作系统下所有轮作的POXC深度在15–30和30–45 cm处随时间显着增加。在2015年秋季和2018年春季，CR–S–HV轮换的累积DOC淋溶量大于CS –S轮换。谷物黑麦在CR–RS–HV和CR–R–S–OR旋转中的包含量减少与2018年春季没有CC的C–S相比，TN的累积浸出量更大。应解决由于CC引入而导致DOC浸出损失增加的问题，并且需要进一步评估其对地表水和地下水中C循环的影响。