Summer Cover Crops Shoot Decomposition and Nitrogen Release in a No-Tilled Sandy Soil

Douglas Adams Weiler,Sandro José Giacomini,Getúlio Elias Pilecco,Celso Aita,Raquel Schmatz,Leonardo Mendes Bastos,Bruno Chaves

doi:10.1590/18069657rbcs20190027

Abstract

ABSTRACT Cover crops have numerous benefits when used in a no-till system. Understanding the processes of decomposition and N release of summer cover crops (SCC) may help select species and management to be used in cropping systems. This study aimed to evaluate C and N loss of SCC shoots. Six SCCs were evaluated: velvet bean (Mucuna aterrima), pearl millet (Pennisetum americanum), dwarf pigeon pea (Cajanus cajan), sunn hemp (Crotalaria juncea), showy rattlebox (Crotalaria spectabilis), and jack bean (Canavalia ensiformis). The [...]

Highlights

No-till is widespread throughout Brazil, but some challenges such as adequate crop rotation and high biomass input into the soil are still not fully addressed by the traditional cropping systems
Understanding the processes of decomposition and N release of summer cover crops (SCC) may help select species and management to be used in cropping systems
This study aimed to evaluate C and N loss of SCC shoots

Summary

Introduction

No-till is widespread throughout Brazil, but some challenges such as adequate crop rotation and high biomass input into the soil are still not fully addressed by the traditional cropping systems. Summer cover crops (SCC) produce high biomass (Aita and Giacomini, 2006; Weiler et al, 2018), but their use is limited because they are grown in the same period as summer cash crops (e.g., soybean and corn), which are typically main sources of income. The potential of biomass production of these species may be even higher when grown alone, even in a relatively short period (Weiler et al, 2018), due to vigorous growth and high capacity of legumes to fix N2 in symbiosis with diazotrophic bacteria (Aita and Giacomini, 2006). Under the same environmental conditions, crop residues differ in decomposition and N release basically due to chemical composition (Trinsoutrot et al, 2000; Redin et al, 2014), generically called quality. High quality crop residues (e.g., high N content and soluble fraction) are decomposed and release N faster than low-quality residues

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