The potential of conservation practices to maintain soil organic C (SOC) and reduce climate change impacts on yields is unknown. This study aimed to validate the DayCent model with observed yield data and the CQESTR model with measured SOC in two agroecosystems, and predict the best practices to sustain SOC under projected climate change. Data were from a conventional tillage (CT) wheat (Triticum aestivum L.)–fallow rotation without N or with 135 kg N ha^–1 fertilizer, and no-till (NT) experiments, NT_A (NT_A0W-F and NT_A135W-F) and NT_B with a wheat–pea (Pisum sativum L.) cover crop (NT_B0W-P and NT_B135W-P) in Oregon; and crop rotations with CT and NT silage or grain corn (Zea mays L.)–soybean [Glycine max (L.) Merr.]–alfalfa (Medicago sativa L.) with or without manure or stover removal or a cover crop in Pennsylvania. Measured and CQESTR-simulated SOC were significantly (p < .0001) correlated (r = .90). In Oregon, predicted SOC to 60 cm increased under NT_A135W-F and NT_B135W-P at 0.05 and 0.08 Mg ha^–1 yr^–1 under projected climate change, respectively. The NT management under dryland production provided a limited SOC increase. In Pennsylvania, predicted SOC to 1 m decreased at 0.07 Mg ha^–1 yr^–1 in corn–soybean under CT or NT with stover removal, but increased by 0.71 Mg ha^–1 yr^–1 in dairy forage NT and manure added under climate change. The responses of SOC to climate change were affected by management, biomass type, edaphic properties, local climate, and agroecosystem.

中文翻译：

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在不同的农业生态系统和不断变化的气候条件下评估农业保护措施在维持土壤有机碳方面的有效性

保持土壤有机碳 (SOC) 和减少气候变化对产量影响的保护措施的潜力尚不清楚。本研究旨在验证 DayCent 模型与观察到的产量数据和 CQESTR 模型与测量的两个农业生态系统中的 SOC，并预测在预计的气候变化下维持 SOC 的最佳实践。数据来自传统耕作 (CT) 小麦 ( Triticum aestivum L.) – 无氮或使用 135 kg N ha ^–1肥料的休耕轮作，以及免耕 (NT) 试验，NT _A（NT _A0 W-F 和 NT _A135 WF ) 和 NT _B与小麦-豌豆 ( Pisum sativum L.) 覆盖作物 (NT _B0 W-P 和 NT _B135WP) 在俄勒冈州；在宾夕法尼亚州，使用 CT 和 NT 青贮饲料或谷物玉米（Zea mays L.）-大豆 [Glycine max (L.) Merr.]-苜蓿（Medicago sativa L.）进行轮作，去除或不去除粪便或秸秆或覆盖作物. 测量的和 CQESTR 模拟的 SOC 显着 ( p <  .0001) 相关 ( r  = .90)。在俄勒冈州，在预测的气候变化下，NT _A135 W-F 和 NT _B135 W-P下的预测 SOC 分别增加0.05 和 0.08 Mg ha ^–1  yr ^–1至 60 cm 。旱地生产下的 NT 管理提供了有限的 SOC 增加。在宾夕法尼亚州，预测的 SOC 下降到 1 m，为 0.07 Mg ha ^–1  yr ^–1在 CT 或 NT 下去除秸秆的玉米 - 大豆中，但在气候变化下添加的奶牛饲草 NT 和粪便中增加了 0.71 Mg ha ^–1  yr ^–1。SOC 对气候变化的响应受管理、生物量类型、土壤特性、当地气候和农业生态系统的影响。