Cover cropping system and mulching can shape soil microbial status in fruit orchards

Andre Freire Cruz,Osvaldo Kiyoshi Yamanishi,Marcio De Carvalho Pires,Sebastiao Alberto Oliveira,Maria Lucrecia Gerosa Ramos,Luiz Eduardo Bassay Blum,Lennon Kaique Beda Do Nascimento

doi:10.1590/1678-992x-2018-0316

Andre Freire Cruz, Osvaldo Kiyoshi Yamanishi + Show 5 more

Open Access

https://doi.org/10.1590/1678-992x-2018-0316

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Abstract

ABSTRACT The use of cover crop in agricultural fields has been well elucidated, especially regarding nitrogen fixation from legume crops and their function as weed protection. Furthermore, to cover crops can benefit the soil microbial community. This study aimed to evaluate and compare the benefits of mulching and cover cropping systems on soil microbial growth and activity, and their effects on plant mineral nutrition in pomelo (Citrus maxima ) and macadamia ( Macadamia integrifolia ) orchards. The treatments included: 1) control [Glyphosate herbicide (Roundup at 4 l per ha)], 2) manual weed control, 3) mulching with dead leaves from their respective trees (macadamia and pomelo), 4) millet, 5) faba bean, 6) millet + faba bean. All the treatments were applied for 120 days before soil and plant leaves were sampled for analyses. Plant mineral nutrition, soil microbial biomass C (MBC) and soil microbial biomass N (MBN); basal respiration (BRA), arbuscular mycorrhizal fungi (AMF) colonization (COL); number of AMF spores (SPO) in soil; total organic carbon (TOC) and total nitrogen (TN) were evaluated. Plant nutrition was not altered by the treatments; however, the MBC, COL and SPO markedly increased in response to mulching and faba bean + millet treatments. Especially in macadamia soils, these treatments had a great response to soil microbiology. Significant negative correlations were also detected for the COL, SPO, BRA and TOC with the Nutrient Balance Index (NBI). These results indicate that in short-term the cover cropping system is useful to improve the soil microbial growth and AMF formation in soils of pomelo and macadam orchards.

Highlights

Macadamia (Macadamia integrifolia Maiden & Betche) and pomelo (Citrus maxima [Burm.)] Merr.) are produced worldwide, and their edible fruits are used for juice and culinary condiments
This study aimed to evaluate and compare the benefits of mulching and cover cropping systems on soil microbial growth and activity, and their effects on plant mineral nutrition in pomelo (Citrus maxima) and macadamia (Macadamia integrifolia) orchards
These results indicate that in short-term the cover cropping system is useful to improve the soil microbial growth and arbuscular mycorrhizal fungi (AMF) formation in soils of pomelo and macadam orchards

Summary

Introduction

Macadamia (Macadamia integrifolia Maiden & Betche) and pomelo (Citrus maxima [Burm.)] Merr.) are produced worldwide, and their edible fruits are used for juice and culinary condiments. One example is grass, which is appropriate and plays an important role in soil management in citrus orchards, where Bahia grass roots could release stimulatory compounds for arbuscular mycorrhizal fungi (AMF), a beneficial microorganism for plant development (Cruz et al, 2003; 2000) Legumes represent another type of cover crop, which are more efficient for nitrogen (N) fixation, essential for plant synthesis of protein and production. These cover crops increase soil organic matter (SOM) content, microbial activity, and decrease erosion and incidence of pests and diseases (Zaccheo et al, 2013). It is not clear whether a mixed grass and legume cover crop in fruit orchards positively affects soil quality and improves plant production

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