Ecosystem services for intensification of agriculture, with emphasis on increased nitrogen ecological use efficiency

Understanding how management can prevent degradation of the structurally fragile soils of the Amazonian periphery

The dynamics and responses to mulching management processes, which affect sustainability in tropical agroecosystems, remain poorly understood. Therefore, this study aims to evaluate and distinguish the short-and long-term effects of mulch of leguminous biomass on fertility of a tropical soil enriched with calcium. This experiment was conducted using the treatments: Long-term mulching (LTM) consisted of planting without mulch in 2019 in soil that had been mulched for six years previously, while short-term mulching (STM) consisted of planting without mulch for six years and with mulch only in 2019. LTM + STM consisted of planting in mulched soil for seven years (from 2013 to 2019), while LTM + synthetic nitrogen (LTM + sN) consisted of the LTM treatment with the addition of 150 kg N ha-1. The remaining treatments were STM + sN; LTM + STM + sN; bare soil with sN, and bare soil without sN as control. In areas with LTM the interactions between products derived from biomass, sN, and Ca resulted in higher total SOC and BS, while STM maintained soil moisture, decreased penetration resistance, and enhanced N uptake providing biological nitrogen able to replace sN for maize nutrition. The positive effects of short- and long-term mulching were cumulative as they increased accumulated N by maize in 163%, and maize grain yield by 125% (4.77-10.78 Mg ha-1) compared to cultivation with sN without mulch. Our results showed that interactions between continuos mulch of leguminous biomass, Ca and sN prevent degradation of agricultural land in Amazonian conditions. Therefore, this combination must be recommended to prevent Amazonian soil management, which in turn reduces the risk of new deforestation in Amazonian periphery.

Could more efficient utilization of ecosystem services improve soil quality indicators to allow sustainable intensification of Amazonian family farming?

In the Amazonian periphery, there are sources of numerous disservices, including deforestation, loss of wildlife habitat and biodiversity erosion. However, there are great opportunities to adopt appropriate agricultural management practices to take advantage of the benefits of ecosystem services for sustainable agricultural intensification. Thus, the aim of this work was to evaluate the effects of certain ecosystem services provided by combined use of legumes with residue of low- and high-quality on soil quality indicators, nitrogen use efficiency and sustainability of maize grain yield in infertile tropical soil. The overarching objective is to determine how ecosystem services can contribute to the improvement of land-use policy to ensure the sustainability of cultivated lands, in such a way that forest can be preserved by avoiding deforestation of other new areas through shifting cultivation systems. Four leguminous tree species were used, two with high-quality residues Leucaena leucocephala (leucaena) and Gliricidia sepium (gliricidia) and two with low-quality residues Clitoria fairchildiana (clitoria) and Acacia mangium (acacia). Maize grain yield was evaluated between 2011 and 2017 in these treatments. In 2018, to assess how ecosystem services affect crop performance, the treatments were divided into ten treatments with and without urea. We conclude that increased uptake of inorganic and organic N by maize resulting from improvement of the soil quality indicators may allow agricultural intensification. This improvement can help meet the challenges of sustainability and feasibility of agroecosystems of the Amazonian periphery by making the agroecosystem more productive year by year. Therefore, our results confirm that the utilization of an ecosystem services style approach can help meet the challenges of sustainability and feasibility in agrosystems of the Amazonian periphery. In addition, these results can contribute to the development of land-use policy in the Amazonian periphery, aiming for the intensification of agriculture in cropped areas to avoid deforestation of new areas from shifting cultivation systems.