Reclaiming Tropical Saline-Sodic Soils with Gypsum and Cow Manure

Francisco Gonçalo Filho,Ray G Anderson,Nildo Da Silva Dias,Jorge F S Ferreira,Raniere Barbosa De Lira,Miguel Ferreira Neto,Cleyton Dos Santos Fernandes,Stella Ribeiro Prazeres Suddarth,Christiano Rebouças Cosme

doi:10.3390/w12010057

Francisco Gonçalo Filho, Ray G Anderson + Show 7 more

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https://doi.org/10.3390/w12010057

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Abstract

Saline-sodic soils are a major impediment for agricultural production in semi-arid regions. Salinity and sodicity drastically reduce agricultural crop yields, damage farm equipment, jeopardize food security, and render soils unusable for agriculture. However, many farmers in developing semi-arid regions cannot afford expensive amendments to reclaim saline-sodic soils. Furthermore, existing research does not cover soil types (e.g., Luvisols and Lixisols) that are found in many semi-arid regions of South America. Therefore, we used percolation columns to evaluate the effect of inexpensive chemical and organic amendments (gypsum and cow manure) on the reclamation of saline-sodic soils in the northeast of Brazil. Soil samples from two layers (0–20 cm and 20–40 cm in depth) were collected and placed in percolation columns. Then, we applied gypsum into the columns, with and without cow manure. The experiment followed a complete randomized design with three replications. The chemical amendment treatments included a control and four combinations of gypsum and cow manure. Percolation columns were subjected to a constant flood layer of 55 mm. We evaluated the effectiveness of sodic soil reclamation treatments via changes in soil hydraulic conductivity, chemical composition (cations and anions), electrical conductivity of the saturated soil-paste extract, pH, and the exchangeable sodium percentage. These results suggest that the combined use of gypsum and cow manure is better to reduce soil sodicity, improve soil chemical properties, and increase water infiltration than gypsum alone. Cow manure at 40 ton ha−1 was better than at 80 ton ha−1 to reduce the sodium adsorption ratio.

Highlights

The use of brackish water in arid and semi-arid regions is increasing due to the increasing food demand by a growing population and declines in the current and future supply of freshwater [1,2,3].the increasing use of brackish water in irrigated agriculture and the potential for inadequate drainage lead to salinization due to the low rainfall and high evaporation rate [4,5]
Statistical tests effect obtained by the combined use gypsum manure as probability the manurelevel, treatments containing included a comparison of means byofthe
We observed that the combination of gypsum with cow manure was more efficient at 40

Summary

Introduction

The increasing use of brackish water in irrigated agriculture and the potential for inadequate drainage lead to salinization due to the low rainfall and high evaporation rate [4,5]. Under these conditions, the soils gradually accumulate soluble salts and alter the physical properties of the soil in the root zone, eventually reducing the potential yield of crops [6]. Soil degradation, caused by increased salinity and sodicity, reduces the soil organic matter and can weaken the soil due to the unstable structure and low water holding capacity. Organic matter applied to the salt-affected soils can increase the physical properties, such as the water retention capacity [7]

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