Predicting the Lime Demand of Arable Soils from pH Value, Soil Texture and Soil Organic Matter Content

Joerg Ruehlmann,Eric Bönecke,Swen Meyer

doi:10.3390/agronomy11040785

Joerg Ruehlmann, Eric Bönecke + Show 1 more

Open Access

https://doi.org/10.3390/agronomy11040785

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Abstract

For more than 40 years, farmers in Germany have used the fertilization recommendation schema provided by the Association of German Agricultural Investigation and Research Institutions (VDLUFA) to quantify the required lime (CaO) demand of arable mineral soils. To be applicable as guidelines in practice, the results of 30 years of fertilization experiments that studied the correlation between crop yields and the actual soil pH, the soil texture, and the soil organic matter (SOM) content were finally condensed into a look-up table system. However, because the original experimental data are no longer accessible, the purpose of this study is to reconstruct the interaction between the three soil parameters and their appropriate lime demands. Therefore, the class-based, stepwise approach of the look-up table system is transferred into a continuous, stepless approach using mathematical models. Under the precondition to preserve the pH-, texture- and SOM-dependent CaO amounts recommended in the look-up system (n = 317) to the greatest extent possible, the algorithm was successful; more than 99% of their variability could be explained by the models. This adaptation helps to meet the accuracy of present-day requirements of precision farming.

Highlights

Agronomic input and management practices have been uniformly applied in agricultural fields considering the spatial heterogeneity of soil properties and the effects of topography
The mathematical models that describe the three-dimensional relationships between the upper pH limits, the mean particle size diameter (MPD) (x) and mean soil organic matter (SOM) contents (y) are given in Equations (3)–(6)
The subdivision of the soil texture and the SOM into classes is a limitation if applied in a precision farming context

Summary

Introduction

Agronomic input and management practices have been uniformly applied in agricultural fields considering the spatial heterogeneity of soil properties and the effects of topography. Uniform agronomic management does not take spatial variability into account. It can be economically and environmentally inefficient [1]. Sitespecific management, as an intrinsic part of precision agriculture, contributes to increasing yield, reducing inputs, and minimizing environmental impact [2,3,4,5,6,7]. Basso et al [8] reported that in many studies in which guidelines for the delineation of management zones were proposed, areas within a field that are homogeneous with respect to yield limiting factors were defined. Compared to traditional uniform-rate application methods, the use of management zone delineation techniques for variable-rate nutrient application increased farm efficiency according to Nawar et al [9]

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