Effect of Long-term Nitrogen, Phosphorus and Potassium Fertilization of Irrigated Corn and Grain Sorghum

This long-term western Kansas study was initiated in 1961 to evaluate responses of irrigated continuous corn and grain sorghum to N, P and K fertilization. Furrow irrigation was used through 2000, and sprinkler irrigation since 2001. No yield benefit to corn from K fertilization was observed in the first 30 years and soil K levels remained high, so the K treatment in the corn study was discontinued in 1992 and replaced with a higher P rate.

This long-term western Kansas study was initiated in 1961 to evaluate responses of irrigated continuous corn and grain sorghum to N, P and K fertilization. Furrow irrigation was used through 2000, and sprinkler irrigation since 2001. No yield benefit to corn from K fertilization was observed in the first 30 years and soil K levels remained high, thus the K treatment in the corn study was discontinued in 1992 and replaced with a higher P rate.

This long-term western Kansas study was initiated in 1961 to evaluate responses of irrigated continuous corn and grain sorghum to N, P and K fertilization. Furrow irrigation was used through 2000, and sprinkler irrigation since that time. No yield benefit to corn from K fertilization was observed in the first 30 years and soil K levels remained high, thus the K treatment in the corn study was discontinued in 1992 and replaced with a higher P rate.

This long-term western Kansas study was initiated in 1961 to evaluate responses of irrigated continuous corn and grain sorghum to N, P and K fertilization. Furrow irrigation was used through 2000, and sprinkler irrigation since 2001. No yield benefit to corn from K fertilization was observed in the first 30 years and soil K levels remained high, thus the K treatment in the corn study was discontinued in 1992 and replaced with a higher P rate.

This long-term western Kansas study was initiated in 1961 to evaluate responses of irrigated continuous corn and grain sorghum to N, P, and K fertilization. Furrow irrigation was used through 2000, and sprinkler irrigation since 2001. No yield benefit to corn from K fertilization was observed in the first 30 years and soil K levels remained high, thus the K treatment in the corn study was discontinued in 1992 and replaced with a higher P rate.

This long-term western Kansas study was initiated in 1961 to evaluate responses of irrigated continuous corn and grain sorghum to N, P, and K fertilization. Furrow irrigation was used through 2000, and sprinkler irrigation since 2001. No yield benefit to corn from K fertilization was observed in the first 30 years and soil K levels remained high, thus the K treatment in the corn study was discontinued in 1992 and replaced with a higher P rate.

This long-term western Kansas study was initiated in 1961 to evaluate responses of irrigated continuous corn and grain sorghum to N, P, and K fertilization. Furrow irrigation was used through 2000, and sprinkler irrigation since 2001. No yield benefit to corn from K fertilization was observed in the first 30 years and soil K levels remained high, thus the K treatment in the corn study was discontinued in 1992 and replaced with a higher P rate.

This long-term western Kansas study was initiated in 1961 to evaluate responses of irrigated continuous corn and grain sorghum to N, P, and K fertilization. Furrow irrigation was used through 2000, and sprinkler irrigation since 2001. No yield benefit to corn from K fertilization was observed in the first 30 years and soil K levels remained high, thus the K treatment in the corn study was discontinued in 1992 and replaced with a higher P rate.

This long-term western Kansas study was initiated in 1961 to evaluate responses of irrigated continuous corn and grain sorghum to N, P, and K fertilization. Furrow irrigation was used through 2000, and sprinkler irrigation since 2001. No yield benefit to corn from K fertilization was observed in the first 30 years and soil K levels remained high, thus the K treatment in the corn study was discontinued in 1992 and replaced with a higher P rate.

This long-term western Kansas study was initiated in 1961 to evaluate responses of irrigated continuous corn and grain sorghum to N, P, and K fertilization. Furrow irrigation was used through 2000, and sprinkler irrigation since 2001. No yield benefit to corn from K fertilization was observed in the first 30 years and soil K levels remained high, thus the K treatment in the corn study was discontinued in 1992 and replaced with a higher P rate.

This long-term western Kansas study was initiated in 1961 to evaluate responses of irrigated continuous corn and grain sorghum to nitrogen (N), phosphorus (P), and potassium (K) fertilization. Furrow irrigation was used through 2000, and sprinkler irrigation since 2001. No yield benefit to corn from K fertilization was observed in the first 30 years and soil K levels remained high, thus the K treatment in the corn study was discontinued in 1992 and replaced with a higher P rate.

This long-term western Kansas study was initiated in 1961 to evaluate responses of irrigated continuous corn and grain sorghum to nitrogen (N), phosphorus (P), and potassium (K) fertilization. Furrow irrigation was used through 2000, and sprinkler irrigation since 2001. No yield benefit to corn from K fertilization was observed in the first 30 years and soil K levels remained high, so the K treatment in the corn study was discontinued in 1992 and replaced with a higher P rate.

This long-term western Kansas study was initiated in 1961 to evaluate responses of irrigated continuous corn and grain sorghum to nitrogen (N), phosphorus (P), and potassium (K) fertilization. No yield benefit to corn from K fertilization was observed in the first 30 years and soil K levels remained high, so the K treatment in the corn study was discontinued in 1992 and replaced with a higher P rate. Nitrogen treatments for corn and grain sorghum were 0, 40, 80, 120, 160, and 200 lb N/A.

This western Kansas study was initiated in 1961 to evaluate responses of irrigated continuous corn and grain sorghum to nitrogen (N), phosphorus (P), and potassium (K) fertilization. No yield benefit to corn from K fertilization was observed in the first 30 years and soil K levels remained high, so the K treatment in the corn study was discontinued in 1992 and replaced with a higher P rate. Nitrogen treatments for corn and grain sorghum were 0, 40, 80, 120, 160, and 200 lb/A.

This western Kansas study was initiated in 1961 to evaluate responses of continuous corn and grain sorghum grown under flood irrigation to nitrogen (N), phosphorus (P), and potassium (K) fertilization. No yield benefit to corn from K fertilization was observed in the first 30 years, and soil K levels remained high, so the K treatment in the corn study was discontinued in 1992 and replaced with a higher P rate.

This western Kansas study was initiated in 1961 to determine responses of continuous corn and grain sorghum grown under flood irrigation to N, P and K fertilization. No yield benefit to corn from K fertilization was observed in the first 30 years, and soil K levels remained high so the K treatment in the corn study was discontinued in 1992 and replaced with a higher P rate.

Long term research conducted since 1962 has shown that P and N fertilizer must be applied for optimum grain yields and profitability of irrigated corn and grain sorghum in western Kansas. The objectives of this study were to determine the optimum rate of N, P, and K fertilizer for irrigated corn and grain sorghum. Various levels of N fertilizer ranging from 0 to 200 lb/A in 40 lb increments were applied to corn and grain sorghum with 40 lb P2O5/A and without P fertilizer.

Long term research has shown that phosphorus (P) and nitrogen (N) fertilizer must be applied for optimum grain yields of irrigated corn and grain sorghum in western Kansas. The objectives of this study were to determine the optimum rate of N, P, and potassium (K) fertilizer for irrigated corn and grain sorghum. Nitrogen and P fertilization increased corn yields more than 100 bu/A in 1998.

Long term research has shown that phosphorus and nitrogen fertilizer must be applied for optimum grain yields of irrigated corn and grain sorghum in western Kansas. The objectives of this study were to determine the optimum rate of nitrogen, phosphorous, and potassium fertilizer for irrigated corn and grain sorghum, and to determine the effect of long term nitrogen and phosphorous applications on nitrate accumulation in the soil profile.

Long term research shows that phosphorus and nitrogen fertilizer must be applied for optimum grain yields of irrigated corn and grain sorghum in western Kansas. In this study, the optimum economic N rate (with P) for corn remains relatively constant at about 160 lb N/acre. Application of the economic optimal N rate does not enhance the potential for nitrate leaching. Fertilizer P at 40 lb P2O5/acre appears to be adequate for producing optimum grain yield of corn.