Spatial variability of soil potassium in sugarcane areas subjected to the application of vinasse.

Laércio A De Carvalho,Cristiane F.B Santos,Carlos A Da Silva Junior,Paulo L Libardi,Ismael Meurer

doi:10.1590/0001-3765201420130319

Abstract

When deposited on land the vinasse can promote improvement in fertility, however, often fertilizer application occurs in areas considered homogeneous, without taking into account the variability of the soil. The objective of this study was to evaluate the effect of vinasse application on potassium content in two classes of soils cultivated with sugarcane, and characterize the spatial variability of soil using geostatistical techniques. In the 2010 and 2011 crop year, soil samples were collected from an experimental grid at 0-0.2 and 0.2-0.4 m depth in three soils cultivated with sugarcane, totaling 90 samplings in each grid, for the determination of pH, calcium (Ca), magnesium (Mg), potassium (K), phosphorus (P), aluminum (Al) and potential acidity (H + Al). The data have been submitted to analysis of descriptive statistics and the K attribute was subjected to geostatistical analysis. The coefficient of variation indicated medium and high variability of K for the three soils. The results showed that the spatial dependence of K increased in depth to FRce and decreased to PHlv, indicating that the attribute could have followed the pattern of distribution of clay in depth. The investigation of the spatial variability of K on the surface and subsurface soils provided the definition of management zones with different levels of fertility, which can be organized into sub-areas for a more efficient management of the resources and the environment.

Highlights

In 2007, increase in the sugarcane industry in Brazil, became the world's largest producer of sugarcane and its derivatives
The objective of this research was to evaluate the effect of vinasse in the potassium in two classes of soil cultivated with sugarcane for two consecutive years, at 0-0.2 and 0.2-0.4 m and characterize the spatial variability of this element in the soil using the techniques of geostatistics
The coefficients of skewness and kurtosis smaller than 1 (FR and layer of 0-0.2 m from the PHlv in two crops), show a tendency to normal, once these parameters are more sensitive to outliers, since the deviations between the mean value are elevated to the third and fourth, respectively (Sanchez et al 2009). These coefficients had values far away from zero in FRce, which according to Gonçalves et al (2001), may indicate that the distribution tails contain very long, compromising the geostatistical

Summary

Introduction

In 2007, increase in the sugarcane industry in Brazil, became the world's largest producer of sugarcane and its derivatives. The production area continues to expand, especially in central-western Brazil, allocating 55 % of production to manufacturing ethanol and 45 % to manufacturing of sugar (Kohlhepp 2010). According to Andrade and Diniz (2007), vinasse is generated at the rate of 13 liters per liter of ethanol, whose composition is quite variable, with about 2 to 6 % of solid constituents, in which the organic matter is highlighted in greater quantity which assists in improving the sum of bases and results in an effect on the consistency, aeration, temperature, and permeability, reducing the plasticity and cohesion of the soil, favoring agricultural operations. In view of the results obtained and the knowledge acquired from tests that contribute to positive effects on the economy of agriculture associated with mineral fertilizers, the economic value gained makes the hypothesis of divergent polluter (Leite 1999)

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Conclusion