Abstract Liming is widely used to decrease soil acidity, and the application of lime alone or in combination with other amendments, such as gypsum, is a viable agricultural practice to improve soil nutrient status and crop yield. However, the effects of applying lime and gypsum alone or in combination on the microbial population and N cycle in intercropped no-till tropical systems are largely unknown. Here, we determined the lasting effects of applying lime and gypsum individually or in combination on soil chemical properties, N uptake by intercropped plants, maize yield, archaeal and bacterial abundances, and N cycle genes in the maize and ruzigrass rhizospheres in a long-term field experiment in tropical soil with a no-till maize and forage ruzigrass intercropping system. Our results showed that the application of lime or lime + gypsum increased soil fertility and the gene abundances of microorganisms responsible for biological nitrogen fixation and reduced gene abundances of nitrification and denitrification in the soil and rhizosphere of ruzigrass and maize. The accompanying increases in Ca2+ and Mg2+ availability, reduced Al3+ levels, and balance of micronutrient availability, mainly Mn, in the soil strongly influenced the responses of N cycle genes and enhanced plant N-acquisition and maize yield.

中文翻译：

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长期石灰和石膏改良剂在热带免耕间作系统中增加固氮作用并降低根际和土壤中的硝化和反硝化基因丰度

摘要 石灰被广泛用于降低土壤酸度，单独施用石灰或与石膏等其他改良剂联合施用是改善土壤养分状况和作物产量的可行农业实践。然而，在间作免耕热带系统中，单独或组合施用石灰和石膏对微生物种群和氮循环的影响在很大程度上是未知的。在这里，我们确定了单独或组合施用石灰和石膏对土壤化学性质、间作植物对氮的吸收、玉米产量、古菌和细菌丰度以及玉米和红枣根际氮循环基因的长期影响在热带土壤中使用免耕玉米和饲草 ruzigrass 间作系统进行田间试验。我们的结果表明，石灰或石灰 + 石膏的施用增加了土壤肥力和负责生物固氮的微生物的基因丰度，并降低了红枣和玉米土壤和根际硝化和反硝化的基因丰度。伴随着土壤中 Ca2+ 和 Mg2+ 有效性的增加、Al3+ 水平的降低以及微量营养素有效性（主要是 Mn）的平衡，强烈影响了 N 循环基因的响应，并增强了植物 N 的获取和玉米产量。