Response of Wheat and Barley Varieties to Phosphorus Fertilizer, 2010

Phosphorus fertilizer represents a significant portion of the cost of producing small grains. Some evidence exists that there are differences in the ability of small grain varieties to take phosphorus up from the soil and utilize this nutrient in the grain. The objective of this study is to determine if barley and wheat varieties grown in Arizona differ in their response to phosphorus fertilizer. A study was conducted for the second year at the Maricopa Agricultural Center testing the response of 7 barley and 14 wheat (12 durum wheat and 2 bread wheat) varieties to 2 phosphorus rates (0 and 100 lbs P₂O₅/acre). The grain yield increase due to phosphorus application averaged across varieties in 2010 was 170 lbs/acre for barley (not statistically significant) and 545 lbs/acre for wheat. The grain yield increase averaged across varieties and years was 331 lbs/acre for barley and 577 lbs/acre for wheat. The barley and wheat varieties did not differ in their grain yield increase due to phosphorus fertilizer in 2010. However, based on 2 years of results, we were able to detect differences among wheat but not barley varieties in their response to P fertilizer. The yield response to P fertilizer (100 lbs P₂O₅/acre) among durum wheat varieties varied from 331 lbs/acre for Alamo to 1063 lbs/acre for Orita. Yecora rojo, a bread wheat, did not respond to P fertilizer