Location: National Soil Erosion ResearchTitle: An important tool with no instruction manual: A review of gypsum use in agriculture
|ZOCA, SAMUEL - Monsanto Corporation|
Submitted to: Advances in Agronomy
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/2/2016
Publication Date: 4/4/2017
Citation: Penn, C.J., Zoca, S.M. 2017. An important tool with no instruction manual: A review of gypsum use in agriculture. Advances in Agronomy. 144:1-44.
Interpretive Summary: Gypsum (Calcium sulfate) has been used in agriculture for hundreds of years. While the benefits of gypsum to soil properties and as a calcium and sulfur source are well known, less is known about quantitative impact on crop yields. This paper summarizes the benefits of gypsum on soils and plants, elaborating on the mechanisms in which gypsum operates. We present different methods for determining ideal gypsum application rates, and summarize the literature regarding potential improvements in crop yields among different soil types and conditions. This paper provides information and criteria to users needing to determine soil gypsum application rates for improving crop yields.
Technical Abstract: Land application of gypsum has been studied and utilized in agriculture and environmental remediation for many years. Most of the published literature has focused on gypsum application impacts on soil properties rather than crop yields. This literature review was conducted to (i) gather results from gypsum application studies relevant to crop grain yield, soil physical–chemical properties, and environmental impact; (ii) report different methods for determining gypsum application rates; (iii) suggest recommendations for future studies on land application of gypsum. Improvement in plant nitrogen use efficiency was rarely discussed as a potential mechanism for improving yield. Free Al activity has been demonstrated to be more correlated with plant yield responses to gypsum application than exchangeable Al or Al saturation. However, few authors reported Al speciation and Al activity. While gypsum is reported to improve soil chemical properties in most cases, these changes do not necessarily translate to increases in yield. Improvements in physical properties for nonsodic soils are not consistent. It is difficult to exactly determine the positive effects from gypsum application that are responsible for yield increases, since there are often many simultaneous physical and chemical changes occurring in the soil. Improvement in crop yield may be a result of an additive or synergistic effect of each of these potential changes. In addition, these potential changes, as varied as they are, appear to also vary with crop, soil type, and rainfall regime. Therefore, meta-analysis of gypsum experiments is highly recommended in order to improve gypsum recommendations across diverse environments.