Potential Nitrogen Contributions by Tropical Legume Summer Cover Crops in Mediterranean-Type Cropping Systems

Shahnaj Parvin; Jason Condon; Terry J. Rose

doi:10.3390/nitrogen3040038

Back

Potential Nitrogen Contributions by Tropical Legume Summer Cover Crops in Mediterranean-Type Cropping Systems

Journal article

Open access

Peer reviewed

Potential Nitrogen Contributions by Tropical Legume Summer Cover Crops in Mediterranean-Type Cropping Systems

Shahnaj Parvin, Jason Condon and Terry J. Rose

Nitrogen, Vol.3(4), pp.592-599

21/10/2022

DOI: https://doi.org/10.3390/nitrogen3040038

Appears in Recent Faculty of Science and Engineering Publications

Files and links (2)

pdf

Potential Nitrogen Contributions by Tropical Legume Summer Cover Crops in Mediterranean-Type Cropping Systems386.76 kBDownload View

Published (Version of record)CC BY V4.0, Open Access

url

Potential Nitrogen Contributions by Tropical Legume Summer Cover Crops in Mediterranean-Type Cropping SystemsView

Published (Version of record)CC BY V4.0, Open

Metrics

4 File views/ downloads

9 Record Views

Abstract

cover crops

short duration summer legumes

B-value

biological N2 fixation

Legume cover crops in temperate cropping systems can fix substantial amounts of nitrogen (N) and reduce N fertiliser requirements for subsequent crops. However, little is known about potential biological N2 fixation by summer cover crop legumes in the short summer fallow in Mediterranean-type cropping systems. Six legume species (balansa clover, barrel medic, mung bean, sunn hemp, lablab and cowpea) were grown for 8–9 weeks in the field in semi-arid southern Australia during the summer fallow, and in a glasshouse experiment, to estimate N2 fixation using the 15N natural abundance method. Cowpea, sunn hemp and lablab produced 1.2–3.0 t ha−1 biomass in the field while balansa clover and barrel medic produced < 1.0 t ha−1. The percent of N derived from the atmosphere (%Ndfa) in the field ranged from 39% in barrel medic to 73% in sunn hemp, but only 15% (balansa clover) to 33% (sunn hemp) in the glasshouse experiment, likely due to higher soil mineral N availability in the glasshouse study. Biological N2 fixation of cowpea and sunn hemp in the field was 46–55 kg N ha−1, while N2 fixation in lablab and mung bean was lower (around 26 kg N ha−1). The N2 fixation in cowpea and sunn hemp of around 50 kg N ha−1 with supplementary irrigation in the field trial likely represents the upper limit of N contributions in the field in typically hot, dry summer conditions in Mediterranean-type climates. Given that any increase in summer cover crop biomass will have implications for water balances and subsequent cash crop growth, maximising N benefits of legume cover crops will rely on increasing the %Ndfa through improved rhizobium strains or inoculation technologies. This study provides the first known estimates of biological N2 fixation by legume cover crops in the summer fallow period in cropping systems in Mediterranean-type environments, providing a benchmark for further studies.

Details

Title: Potential Nitrogen Contributions by Tropical Legume Summer Cover Crops in Mediterranean-Type Cropping Systems
Creators: Shahnaj Parvin - Southern Cross University
Jason Condon - Charles Sturt University
Terry J. Rose - Southern Cross University
Publication Details: Nitrogen, Vol.3(4), pp.592-599
Publisher: MDPI
Identifiers: 991013075903802368
Copyright: © 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
Academic Unit: Faculty of Science and Engineering; Science; Centre for Organics Research
Language: English
Resource Type: Journal article

Potential Nitrogen Contributions by Tropical Legume Summer Cover Crops in Mediterranean-Type Cropping Systems

Files and links (2)

Metrics

Abstract

Details

Southern Cross University Social media