Regression-based phosphorus recommendation model for Washington Navel

Abstract

Many methods have been proposed to recommend phosphorus fertilizer, but none of them can quantitatively determine the plant phosphorus required. In this method, which is called “Integrated Plant and Soil System” (IPSS), the required phosphorus of the plant is calculated quantitatively, based off of the correlation between soil phosphorus, soil properties, and plant organs phosphorus. For this purpose, 39 Orange orchards were chosen in Jahrom (Iran). In each orchard during two consecutive years, samples were taken from the plant organs and soil of the root zone and phosphorus was measured. A multivariable regression was established between variables that had a significant correlation with soil phosphorus. The result of IPSS was two regression models between soil and fruit phosphorus. A regression model for high yield orchards (Y2 = –121.3799 + 0.1256308X2), and the other for orchards that have a phosphorus deficiency (Y1 = –96.4673 + 0.120549X1). According to these regressions, calculating the amount of phosphorus required for orange trees is possible.

Keywords:

• fertilizer recommendation
• regression models
• soil phosphorus
• Washington navel orange