Use of a New Deep Vertical Gypsum Placement Practice on Corn and Soybean Production in Conservation Tillage Systems

Theodore G Blumenschein,Kelly A Nelson,Peter P Motavalli

doi:10.5539/jas.v10n11p1

Abstract

Corn (Zea mays L.) and soybean (Glycine max (L.) Merr.) production in claypan soils in the north central U.S. may be constrained by the presence of acidic subsoils. Subsoil acidity can inhibit root growth leading to decreased drought tolerance and grain yields. In conservation tillage systems, management options to incorporate gypsum applications may be limited; thereby reducing available practices to lower subsoil acidity. The objective of this study was to determine the effects of surface placement of gypsum compared to a new practice for deep vertical placement of gypsum on corn and soybean plant growth and yields in a conservation tillage system. Field trials were conducted from 2012 to 2016 in northeast Missouri (USA) with treatments of gypsum (0, 2.9, and 5.2 Mg ha-1) broadcast on the soil surface or applied in a deep vertical band to a depth of 51 cm. Surface and deep banding of gypsum had inconsistent effects on corn and soybean plant heights, plant population and yields. However, deep banding of gypsum resulted in a 6.4 to 9.8% decrease in corn yields and a 9.9 to 13.0% decrease in soybean yields depending on the time after application. These results indicate that further research is warranted in conservation tillage systems in claypan soils to examine modification to the deep vertical placement practice or combining applications of surface-applied gypsum and deep placement of lime in order to develop a practice that will be more effective in overcoming subsoil acidity.

Highlights

The objective of this research was to evaluate the impacts of gypsum placement, including use of a new deep placement practice, at differing rates on corn and soybean plant growth and grain yields in a conservation tillage system situated in poorly drained claypan soils that exhibit subsoil acidity
Excessive salinity caused by banding a high rate of gypsum-related byproducts, such as flue gas desulfurization gypsum, may reduce plant growth especially under poor drainage conditions when the salts are not leached out of the rooting zone (Wang & Yang, 2018)
This research suggests that deep vertical placement application of gypsum to claypan soils under a conservation tillage system does not increase corn or soybean yields, but may reduce crop yields when this material is placed in a deep band at the rates evaluated in this experiment

Summary

Introduction

Soil acidity is a major constraint to increased global agricultural productivity and this acidity is projected to increase in developing nations where atmospheric sulfur emissions have risen rapidly (Sumner et al, 1986; Tupper et al, 1987; Mclay et al, 1994; Farina et al, 2000a, 2000b; Kuylenstierna et al, 2001; Godsey et al, 2007). In areas with low levels of soil calcium (Ca) and elevated exchangeable aluminum (Al+3) resulting from acidic soil conditions, treatments of gypsum (CaSO4) or gypsum byproducts, such as flue gas desulfurization gypsum, have shown to be effective in ameliorating these limitations to crop growth and development (Sumner et al, 1986; Farina et al, 2000a, 2000b; Wang & Yang, 2018). Overall advantages of gypsum application in agricultural fields include prevention and correction of sodicity, greater stability of soil organic matter, more stable soil aggregates, improved water penetration into soil, increased levels of soil Ca and S for plant use, and more rapid seed emergence (Wallace, 1994; Watts & Dick, 2014)

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Conclusion