No description available.

No description available.

No description available.

Optimum design and management of irrigated wheat production is limited by the scarcity of information available on yield variability. The purpose of this study was to evaluate the spatial variability in soil-water parameters and the effects compared to grain yield response under level-basin irrigation. Three levels of seasonal irrigation water and two border lengths were used. Grain yields were found to increase significantly with the amount of water applied and soil water depletion (estimate of crop evapotranspiration), although yield variability was greater with reduced or deficit irrigations. Variations in soil water content were responsible for about 22% of the variability in grain yield, indicating that other soil and crop- related factors had a significant influence on production. Spatial dependence was exhibited over a greater distance at the wetter compared with the drier irrigation regimes.

No description available.

No description available.

No description available.

Additional data to calibrate and refine current guidelines for interpreting soil test values is an ongoing need in Arizona. This includes information for soils testing above and below the level that may currently be considered adequate for optimum plant growth. An experiment was conducted at the Maricopa Agricultural Center during the 1985-86 crop year to evaluate the response of durum wheat to the application of phosphorus (P), potassium (K), magnesium (Mg), or zinc (Zn) on a soil testing adequate or higher for all of these nutrients. Grain yields from plots receiving every combination of three of the four nutrients were compared to yields obtained when all four nutrients were applied. No significant change in grain yield was measured as a result of witholding any one of the nutrients. Current guidelines used to interpret soil test results for wheat production correctly predicted the nutrient status of this soil with respect to P, K, Mg, and Zn.

A four-year experiment was conducted at the Mesa Agricultural Center to study the use of dried sewage sludge from the City of Phoenix as a source of plant nutrients in the commercial production of barley grain. The objective was to compare the effects of sewage sludge and commercial fertilizer on barley growth, grain yield, and quality. Three fertilizer treatments were used: (1) suggested rates of nitrogen (N), phosphorus (P), and potassium (K) in Arizona, (2) dried sewage sludge to supply plant-available N in amounts equal to the suggested rate, and (3) N, P, and K from inorganic fertilizers in amounts equal to those in sewage sludge. Characteristics of barley growth, grain yield, and quality were similar for the three fertilizer treatments. Barley can utilize the fertilizer nutrients in dried sewage sludge in the production of grain as effectively as it can utilize the fertilizer nutrients in inorganic fertilizer.

No description available.