Assessing the importance of soil testing in fertilizer use intensity: an econometric analysis of phosphorus fertilizer allocation in dairy farm systems.

Abstract

As global population rises there is added pressure on agricultural systems to become more intensified which in turn is increasing the concerns about food security.. On the other hand International and European organizations call their members to commit to environmental protection, including preservation of water quality. In many European countries agriculture is reported as a major water pollutant, with Phosphorus (P) considered to be contributing highly to water quality degradation. Hence, controlling phosphorus fertilizer use is expected to be a priority. P chemical fertilizer continues to be a considerable component both for the production systems as well as for the degradation of water quality, regardless of the fact that its use has been decreasing. Phosphorus fertilizer recommendations are based on soil P content. As farmers are responsible for the amount of phosphorus fertilization on their farm, they are expected to be aware of their soil P status conditions. Farmers are advised to soil test their farms before they allocate P fertilizers, based on the assumption that soil test result will assist them in making an informed decisions, and lately policy design discussions mention inclusion of soil testing in the agricultural policies regulations. To ensure the correctness of this decision a good understanding of the relation between soil testing and P fertilizer allocation is required. This paper examines the case of Ireland, where farmers are strongly encouraged to perform soil tests on their farms on a regular basis, assuming that it leads to reduced P fertilizer use intensity. We use National farm data to investigate the relation between a farmer’s decision to soil test and the Phosphorus fertilizer use intensity. A censored tobit model was developed to identify significant relationships between soil testing and Phosphorus fertilizer amount applied at farm level, among other factors that are considered important for fertilizer use intensity. Results indicate a negative relationship suggesting that soil testing leads to reduced P fertilizer use. This result highlights the need for policy recommendations that would provide farmers with the adequate knowledge and tools for soil testing and effective phosphorus management.