Sena Virley G L, de Moura Emanoel G, Macedo Vinícius R A, Aguiar Alana C F, Price Adam H, Mooney Sacha J, Calonego Juliano C
Department of Crop Science College of Agricultural Sciences São Paulo State University Botucatu São Paulo 18.610-307 Brazil.
Postgraduate Program in Agroecology Maranhão State University São Luis Maranhão 65000-000 Brazil.
Ecosphere. 2020 Feb 7;11(2):e03028. doi: 10.1002/ecs2.3028. eCollection 2020 Feb.
In weathered tropical soil, low nutrient use efficiency can lead to agricultural systems becoming unsustainable. Therefore, tropical agriculture is highly dependent on ecosystem services, such as nutrient recycling and carbon sequestration, to enhance soil fertility, increase nutrient uptake, and facilitate sustainable production of agricultural goods. This research aimed to find the balance between sustainability and profitability of tropical agriculture by evaluating the changes in soil caused by the ecosystem services provided by the biomass of leguminous trees () and assessing how these changes (associated with potassium) can affect nitrogen-use efficiency and maize yield. An experiment was conducted testing the impact of biomass addition vs. bare soil, with or without addition of both nitrogen and/or potassium. Changes in soil organic matter, (SOM) base cations sum, soil resistance, N uptake, N-use efficiency, and maize yield were evaluated. Gliricidia biomass, when used with N and K, contributed to increasing SOM by 5.0 g/kg and the sum of base cations by 1458. 65 kg/ha in the 0-30 cm layer. Moreover, grain yield was increased by approximately 70% in the treatments with when compared to treatments without biomass where yield was very low. In bare soil, the additional yield of 1.5 tons/ha would not be enough to convince farmers to change slash and burn to conventional bare soil systems. Our results showed that leguminous trees, such as Gliricidia, might contribute to ensuring sustainable agricultural intensification in humid tropical soils with low natural fertility by providing ecosystem services such as biomass production, carbon sequestration, base cation recycling, and increased N acquisition. These findings might be an important strategy to replace the common slash-and-burn-system and preserve the rainforest against the traditional shifting cultivation system. In contrast, the conventional system with bare soil showed that the addition of nitrogen was unfeasible, mainly in conditions of high rainfall precipitation. In these circumstances, the use of potassium may increase nitrogen-use efficiency only when biomass is not used.
在风化的热带土壤中，养分利用效率低下会导致农业系统变得不可持续。因此，热带农业高度依赖生态系统服务，如养分循环和碳固存，以提高土壤肥力、增加养分吸收并促进农产品的可持续生产。本研究旨在通过评估豆科树木生物量提供的生态系统服务对土壤造成的变化，并评估这些变化（与钾有关）如何影响氮素利用效率和玉米产量，来找到热带农业可持续性与盈利能力之间的平衡。进行了一项实验，测试添加豆科树木生物量与裸土相比的影响，以及是否添加氮和/或钾。评估了土壤有机质、（SOM）碱金属阳离子总量、土壤抗性、氮吸收、氮利用效率和玉米产量的变化。当与氮和钾一起使用时，马占相思生物量有助于在0至30厘米土层中将土壤有机质增加5.0克/千克，碱金属阳离子总量增加1458.65千克/公顷。此外，与没有生物量且产量很低的处理相比，添加马占相思生物量的处理的谷物产量提高了约70%。在裸土中，每公顷额外增加1.5吨的产量不足以说服农民将刀耕火种改为传统的裸土系统。我们的结果表明，豆科树木，如马占相思，可能通过提供生物量生产、碳固存、碱金属阳离子循环和增加氮素获取等生态系统服务，有助于确保在自然肥力较低的潮湿热带土壤中实现可持续的农业集约化。这些发现可能是取代常见的刀耕火种系统并保护雨林免受传统轮耕系统影响的重要策略。相比之下，传统的裸土系统表明，添加氮是不可行的，主要是在高降雨条件下。在这些情况下，只有在不使用生物量时，使用钾才可能提高氮素利用效率。
