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Long-term intensive use of mineral fertilizers in double rice-cropping systems has led to soil acidification and soil degradation. Manure fertilization was suggested as an alternative strategy to mitigate soil degradation. However, the effects of long-term mineral and manure fertilization on rice grain yield, yield stability, soil organic carbon (SOC) content, soil total nitrogen (TN) content, and the underlying mechanisms are unclear. Based on a long-term experiment established in 1981 in southern China, we compared four treatments: no fertilizer application (Control); application of nitrogen–phosphorus–potassium (NPK); NPK plus green manure in early rice (M1); and M1 plus farmyard manure in late rice and rice straw return in winter (M2). Our results showed that 37 years of NPK, M1, and M2 significantly increased rice grain yield by 54%, 46%, and 72%, and yield stability by 22%, 17%, and 9%, respectively. M1 and M2 significantly increased SOC content by 39% and 23% compared to Control, respectively, whereas there was no difference between Control and NPK. Regarding soil TN content, it was significantly increased by 8%, 46%, and 20% by NPK, M1, and M2, respectively. In addition, M2 significantly increased bacterial OTU richness by 68%, Chao1 index by 79%, and altered the bacterial community composition. Changes in soil nutrient availability and bacterial Simpson index were positively correlated with the changes in grain yield, while shifts in bacterial community were closely related to yield stability. This study provides pioneer comprehensive assessments of the simultaneous responses of grain yield, yield stability, SOC and TN content, nutrient availability, and bacterial community composition to long-term mineral and manure fertilization in a double rice-cropping system. Altogether, this study spanning nearly four decades provides new perspectives for developing sustainable yet intensive rice cultivation to meet growing global demands. [ABSTRACT FROM AUTHOR]

Ammonia (NH 3) emissions are an important pathway of nitrogen (N) losses in rice paddies. Lime application and straw retention are common practices to enhance soil fertility in acidic soils. However, the interaction of lime and straw application on NH 3 emissions from paddies remain unclear. Here, a factorial experiment was employed to examine the interactive effects of slaked lime (i.e., Ca(OH) 2) and straw retention on NH 3 emissions and NH 3 emission factors (EFs) in a double-cropped rice field. The results showed that compared to unlimed treatments, liming promoted NH 3 emissions and EFs by 98.6% and 90.2% in the early rice growth season, respectively, with increases of 16.3% and 15.7% in the late rice growth season. Relative to straw removal, straw retention increased NH 3 emissions by 52.8% in the early rice growth season but did not alter EFs, while reducing NH 3 emissions by 9.9% and EFs by 25.7% in the late rice growth season. Liming interacted with straw retention to increase NH 3 emissions and EFs in the early rice growth season. Under straw retention, liming promoted NH 3 emissions by 147.7% and EFs by 148.3%, whereas liming raised NH 3 emissions and EFs only by 45.3% and 45.5% under straw removal, respectively. Liming had no significant interactions with straw retention on NH 3 emissions and EFs in the late rice growth season. It is likely that the decomposition extent of straw can alter the response of NH 3 emissions to liming. Thus, NH 3 emission inventories should take into account the interaction of liming and straw retention and its dependence on rice growth seasons in double-cropped rice systems with acidic soils. • Liming alone increased NH 3 emissions and NH 3 emission factors (EFs) in a double-cropped rice field. • Straw retention alone promoted NH 3 emissions in the early rice growth season but reduced them in the late rice growth season. • Liming interacted with straw retention to increase NH 3 emissions and EFs in the early rice growth season. • Liming had no significant interactions with straw retention on NH 3 emissions and EFs in the late rice growth season. [ABSTRACT FROM AUTHOR]