Nitrogen Transfer from Cover Crop Residues to Onion Grown under Minimum Tillage in Southern Brazil

Leoncio De Paula Koucher,Corina Luisa Videira De Abreu Fernandes Carranca Carranca,Monique Souza,Claudinei Kurtz,Vilmar Müller Júnior,Sandro José Giacomini,Jucinei José Comin,Gustavo Brunetto,Rafael Da Rosa Couto,Andria Paula Lima

doi:10.1590/18069657rbcs20160347

Abstract

ABSTRACT Nitrogen derived from cover crop residues may contribute to the nutrition of onion grown under minimum tillage (MT) and cultivated in rotation. The aim of this study was to evaluate the N transferred from different cover crop residues to the onion crop cultivated under MT in southern Brazil. In June 2014, oilseed radish, black oat, and oilseed radish + black oat residues labeled with 15N were deposited on the soil surface before transplanting onions. During the growth season and [...]

Highlights

Cover crops offer many benefits for farmers seeking to reduce their reliance on external inputs (Haramoto and Gallandt, 2004)
Oilseed radish decomposed faster than other residues and 4 % of residue N was recovered in leaves and bulbs at harvest, but in general, N in plant organs was derived from sources other than the cover crop residues
In onions grown under the oilseed radish (OR) + black oat (BO) combination, the highest N content was observed in leaves collected at 44 days after residue addition (Table 3)

Summary

Introduction

Cover crops offer many benefits for farmers seeking to reduce their reliance on external inputs (Haramoto and Gallandt, 2004). In the MT system, onion is planted under residues of cover crops such as black oats (Avena strigosa Schreb) and oilseed radish (Raphanus sativus L.) grown during the fall and winter, alone or intercropped (Souza et al, 2013). These residues protect the soil against the impact of raindrops, reduce runoff, suppress weed growth, and increase soil water storage and nutrient release (Haramoto and Gallandt, 2004; Mbuthia et al, 2015). It is expected that most N forms derived from the decomposition of residues in the soil are recovered by onion, promoting plant N nutrition and reducing the levels of mineral N accumulated in the soil, decreasing the potential for N losses through leaching (Haramoto and Gallandt, 2004)

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