Application of manure has been recommended as an effective strategy to to mitigate climate change. However, the magnitude of greenhouse gases emission derived by application of manure to agricultural soils across environmental conditions still remains unclear. Here, we synthesized data from 379 observations in China and quantified the responses of soil nitrous oxide (N₂O), carbon dioxide (CO₂) and methane (CH₄) emissions to manure (Org-M) in comparison to chemical fertilizers (Min-F) or non-fertilizers (Non-F). The results showed that N₂O, CO₂and CH₄emissions were significantly affected by Org-M compared to Min-F (percentage change: −3, +15 and +60%,P < 0.05) and Non-F (percentage change: +289, +84 and +83%,P < 0.05), respectively. However, at the same amount of total N input, Org-M decreased soil N₂O emission by 13% and CH₄emission by 12%, and increased soil CO₂emission by 26% relative to Min-F in upland soils. For paddy soils, N₂O, CO₂and CH₄emissions differed by −3%, −36% and +84% between Org-M and Min-F (i.e., Org-M minus Min-F). Thus, practices such as application of manure instead of chemical fertilizer and decreasing nitrogen input rate need to be highly considered and optimized under different soils and climate conditions to mitigate GHGs emission in China.

The assessment of soil organic carbon (SOC) in mountainous karst areas is very challenging, due to the high spatial heterogeneity in SOC content and soil type. To study and assess the SOC storage in mountainous karst areas, a total of 22,786 soil samples were collected from 2,854 soil profiles in Guizhou Province in Southwest China. The SOC content in the soil samples was determined by the oxidation of potassium dichromate (K₂Cr₂O₇), followed by titration with iron (II) sulfate (FeSO₄). The SOC storage was assessed based on different land uses. The results suggested that the average SOC density in the top 1.00 m of soil associated with different land uses decreased in the following order: Croplands (9.58 kg m⁻²) > garden lands (9.07 kg m⁻²) > grasslands (8.07 kg m⁻²) > forestlands (7.35 kg m⁻²) > uncultivated lands (6.94 kg m⁻²). The SOC storage values in the 0.00–0.10 m, 0.00–0.20 m, 0.00–0.30 m and 0.00–1.00 m soil layers of Guizhou Province were 0.50, 0.87, 1.11 and 1.58 Pg, respectively. The SOC in the top 0.30 m of soil accounted for 70.25% of the total within the 0.00–1.00 m layer in Guizhou Province. It was concluded that assessing SOC storage in mountainous karst areas was more accurate when using land use rather than soil type. This result can supply a scientific reference for the accurate assessment of the SOC storage in the karst areas of southwestern China, the islands of Java, northern and central Vietnam, Indonesia, Kampot Province in Cambodia and in the general area of what used to be Yugoslavia, along with other karst areas with similar ecological backgrounds.

Irrigated paddy rice (Oryza sativa L.) is a staple food for roughly half of the world’s population. Concerns over water quality have arisen in recent decades, particularly in China, which is the largest rice-producing country in the world and has the most intensive use of nutrients and water in rice production. On the one hand, the poor water quality has constrained the use of water for irrigation to paddy systems in many areas of the world. On the other hand, nutrient losses from paddy production systems contribute to contamination and eutrophication of freshwater bodies. Here, we review rice production, water requirement, water quality issues, and management options to minimize nutrient losses from paddy systems. We conclude that management of nutrient source, rate, timing, and placement should be combined with the management of irrigation and drainage water to reduce nitrogen and phosphorus losses from paddies. More research is needed to identify cost-effective monitoring approaches and mitigation options, and relevant extension and policy should be enforced to achieve water quality goals. The review is preliminarily based on China’s scenario, but it would also provide valuable information for other rice-producing countries.

基于自然解决方案(nature-based solutions, NbS)是一种高效利用自然资源与保护生态系统并行的行动，可解决当今面临的来自社会、经济和环境方面的挑战，是国际上普遍认可的生态系统管理前沿方法之一。将基于自然解决方案应用于乡村空间重构，不仅能够有效缓解乡村发展面临的生态环境危机，还可进一步激发乡村发展潜力，促进乡村地域的全面振兴。论文梳理了基于自然解决方案的概念演进，并基于地方政府、村委会、村域经营主体和村民等不同利益主体视角，从生态空间、实体空间、经济空间和社会空间4个方面探讨了基于自然解决方案的乡村空间重构概念内涵。随后，分别从生态保护和生态景观优化、农村地区生产生活空间优化和土地整治与农业转型、自然景观商品化以及平衡不同利益相关者的需求和期望等方面系统分析了基于自然解决方案的乡村生态空间、实体空间、经济空间和社会空间重构的研究进展。最后指出，未来可着重从NbS理念的本土化改造、多部门协同合作机制构建、资源与资金配置的优化策略探究、社会经济影响的阶段评估、社会经济效益量化方法的应用等方面深入开展基于自然解决方案的乡村空间重构研究。