Changes in soil chemical and physical properties in pasture fertilised with liquid swine manure

Douglas Leandro Scheid,Marlo Adriano Bison Pinto,Maurício Roberto Cherubin,Márcia Gabriel,Clovis Orlando Da Ros,Vanderlei Rodrigues Da Silva,Rodrigo Ferreira Da Silva

doi:10.1590/1678-992x-2019-0017

Douglas Leandro Scheid, Marlo Adriano Bison Pinto + Show 5 more

Open Access

https://doi.org/10.1590/1678-992x-2019-0017

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Abstract

ABSTRACT: Chemical and physical properties of soil can be altered with the successive application of liquid swine manure (LSM), also known as slurry. Therefore, monitoring the impact of LSM is essential to an assessment of the potential agronomic and environmental benefits and risks associated with management practices. The aim of this study was to evaluate the effects of LSM on the chemical and physical attributes of soil under pasture (Cynodon spp.), located in southern Brazil. Four areas were sampled: three areas cultivated with Cynodon spp. pasture with successive applications of 200 m3 ha–1 y–1 of LSM for three, eight and 15 years; and untreated native forest as a reference. The soil attributes evaluated were: organic carbon (OC), active (pH water) and potential acidity (H + Al+ 3), nutrient availability (i.e., P, K, Ca, Mg, Cu and Zn), soil bulk density, macro, micro and total porosity. Successive applications of LSM on pasture reduced soil active acidity, and increased the soil organic C and plant-available N, P, Ca, Mg, Cu and Zn contents. These effects were more intense with time and in the shallowest layers, i.e. 0-10 cm. Excessive increases in P, Cu and Zn in the soil should be carefully monitored to minimize the contamination risks to soil, ground and surface waters. Soil physical attribute changes were more associated with land use (pasture versus native forest) than LSM use, and LSM applications induced slight improvements in the soil structural quality over time.

Highlights

The production of pork meat is concentrated in family farms in southern Brazil, and plays a fundamental role in the socio-economic development of the region
Soil physical attribute changes were more associated with land use than liquid swine manure (LSM) use, and LSM applications induced slight improvements in the soil structural quality over time
Organic C and attributes of soil acidity The successive applications of LSM for 15 years in Cynodon spp. cultivation promoted increases in soil organic C levels at levels equivalent to those found in native forest (Figure 2A and Table 2)

Summary

Introduction

The production of pork meat is concentrated in family farms in southern Brazil, and plays a fundamental role in the socio-economic development of the region. The environmental impacts associated with large amounts of manure produced by intensive swine production in small farms have caused intense debates, threatening the sustainability of this productive chain. In Brazil, 43 million animals are slaughtered annually (FAO, 2019), producing ~300 million liters of liquid swine manure (LSM) daily (Oliveira et al, 2017). LSM has been used as organic fertilizer, mainly as a source of N (Woli et al, 2013), in areas cultivated with pastures and annual crops (Freitas et al, 2018; Guardini et al, 2012; Oliveira et al, 2017). Successive applications of LSM, as organic fertilizer, enhance the growth and accumulation of dry matter biomass of Cynodon sp. Tifton 85 (Ames et al, 2014), which is well-adapted to the subtropical climate conditions of southern Brazil, and is characterized by rapid growth and high digestibility (Burton, 2001)

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