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Interpretive Summaries:
1998 - Potassium Nutrition of Pistachio: Development of Fertilizer Recommendations and Diagnostic Procedures
1997 - Potassium (K) nutrition of pistachio: development of fertilizer recommendations and diagnostic procedures
1996 - Potassium (K) Nutrition of Pistachio: Development of Fertilizer Recommendations and Diagnostic Procedures
Potassium Nutrition of Pistachio: Development of Fertilizer Recommendations and Diagnostic Procedures, 1998
The primary objectives of this study were to determine the response of pistachio to potassium (K) application and to develop optimal K fertilizer programs. It was initiated in 1996 and terminated at the end of 1998.
The study was conducted on mature ‘Kerman” pistachio trees in three commercial orchards. Treatments consisted of four annual fertilizer rates (0, 120, 240 and 360 lb/A of K2O), three K fertilizers (K2SO4, KCl and KNO3), and two application methods (micro-sprinklers vs. soil banding). Potassium application, regardless of K source, application rate and method, significantly increased nut yield and quality, soil K availability, and leaf K level. The economic effects of K use were evaluated using net return and value to cost ratio (VCR, the ratio of the value of increased yield from K used to the cost of K used). Potassium application was shown to be highly profitable to growers, with net returns for K use in the range of $378 to $1,648 per acre and VCRs of 3.5 to 30.5. Based on both agronomic and economic results of this study it is recommended to apply K fertilizers via fertigation systems at the rate of 120 to 240 lb/A of K2O (at least for low and medium testing soils), using either K2SO4 or KCl.
Based on the above recommendation, estimated annual increase in K consumption on pistachio in California up to 14,800 tons of KCl or 17,600 tons of K2SO4 is possible. These data are generally applicable to other nut crops in the Central Valley so they will impact not just pistachio, but also other crops such as almond and walnut. CA-19F
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