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

Virley G L Sena,Alana C F Aguiar,Sacha J Mooney,Juliano C Calonego,Adam H Price,Emanoel G De Moura,Vinícius R A Macedo

doi:10.1002/ecs2.3028

Abstract

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 (Gliricidia) and assessing how these changes (associated with potassium) can affect nitrogen‐use efficiency and maize yield. An experiment was conducted testing the impact of Glircidia 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 Gliricidia 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.

Highlights

Agricultural products are essential to human well-being, but the sustainable production of agricultural goods is highly dependent on the services provided by neighboring natural ecosystems (Malhi 2012)
Improvement in soil fertility Our findings showed that was a positive effect of the biomass of Gliricidia on permanence of both organic carbon and base cations in the root zone
The effect of biomass and potassium on NRE and NAE was made explicit by comparison with other treatments, confirming the importance of N management for agroecosystem success in the humid tropics. Leguminous trees such as Gliricidia might contribute to achieving sustainable agricultural intensification in soil with low natural fertility, as is characteristic of the humid tropics, by providing ecosystem services such as biomass production, carbon sequestration, base cation recycling, and increased N acquisition

Summary

Introduction

Agricultural products are essential to human well-being, but the sustainable production of agricultural goods is highly dependent on the services provided by neighboring natural ecosystems (Malhi 2012). The services provided by natural ecosystems, such as nutrient cycling and increased carbon sequestration in the soil root zone, is essential to the maintenance of soil structure and the enhancement of soil fertility. These processes drive the efficiency by which plants acquire the major nutrient nitrogen (N), which has been identified as one of the most important targets for improving root acquisition efficiency (Chapman et al 2012). Irregular precipitation rates occurring where soils undergo hardsetting during drying cycles can result in nitrogen uptake that is impaired in conditions of both high rainfall (by nitrogen removal) and low rainfall (by reduced root growth in hardsetting soil; Moura et al 2018)

Objectives

Methods

Results

Discussion

Conclusion