The Southern San Joaquin Valley Management Practices Evaluation Program (MPEP) is developing and compiling online tools and resources for growers.

Y-to-R Calculator

The Crop Yield to Nitrogen Removed Calculator (also known as the Y-to-R Calculator) estimates N removed (R) and the ratio of N applied (A) to N removed (A/R). Results can be calculated on inputs for a single crop or for multiple crops. Conversion factors were developed by UC Davis (Geisseler 2016) based on the best available information. The conversion factors will continue to be refined as additional research becomes available.

Irrigation Water N Calculator

The N supply in irrigation water is a crucial component of N management. This calculator allows users to calculate N supply from inches of applied water and N (nitrate and/or ammonium) content from surface and/or groundwater.

Within-field Variability Viewer

Management is often discussed at the field or block level, even though we know that individual fields or blocks may contain very distinct units due to soil or topographic variation. Precision agriculture increasingly provides options to manage this variation, but a first question is, how much variation exists within a given area? This online mapping tool allows the user to zoom into specific fields, complete with field boundaries, and view evapotranspiration variability within each field.

Management Practice Performance (MaPP) Decision Support
Tool (in development)

This online interactive tool will allow irrigators to select a location and crop, and evaluate management options from the standpoint of the relative risk of N loss through leaching from the root zone. Irrigated landscapes vary greatly with respect to the degree of difficulty in retaining N in the root zone for use by crops. The performance of various combinations of management practices applied to a specific crop is influenced by soil, climatic, topographic, and other agronomic factors. MPEP modeling efforts will assess common sets of management practices across the full range of Central Valley conditions.

Events Calendar

This site is a compilation of outreach events related to agricultural management practices in the Central Valley.