Nutrient Management for Wheat

Improving Nutrient Management for Wheat

through Comprehensive Soil and Crop Survey

Olga S. Walsh,  and Jordan R. McClintick-Chess, University of Idaho, Plant Sciences Department

Sanaz Shafian,University of Idaho, Department of Soil and Water Systems,

 Juliet Marshall,University of Idaho, Department of Entomology, Plant Pathology and Nematology

Soil testing is a necessary component of successful and sustainable soil nutrient management for crop producers. Proper soil testing is essential to ensure optimal fertilizer usage resulting in maximum economic and agronomic returns with minimal environmental impact.

Local growers, extension educators, and crop consultants have expressed the need for enhancing their knowledge of sustainable soil nutrient management by boosting their understanding of soil sampling/testing. Despite substantial educational efforts, many growers do not test their soil’s fertility on a regular basis. This is especially true for many wheat growers in southern Idaho, where other crops such as potatoes produce the highest revenue, and nutrient management for wheat is often overlooked.

Improving grower understanding of on-farm soil fertility and soil residual nutrient levels as well as being aware of what kind of response can be expected from N and P fertilizer application are key to making informed and wise nutrient management decisions.

OBJECTIVE: To illustrate response of wheat to N and P fertilizer.

Nitrogen (P) and phosphorus (P) response plots were established at the University of Idaho Parma R&E Center. On April 3, 2019, soft white spring wheat (Seahawk) was planted with H&N Equipment small plot drill using 276 plants m2 seeding rate. At planting, 5 N 5 P levels were applied, each treatment was replicated 3 times. The research plots were hand-harvested on August 22, 2019, and data on wheat biomass and grain production was analyzed. Grain production was calculated as a product of kernels head-1 and kernel weight. The Duncan's Multiple Range Test was used in the SAS 9.4 statistical software to determine the differences between treatments at the 95% confidence level.

In general, plant height increased with increased N rates. Plant height was optimized at 250 lb N ac-1, increasing N rate to 300 lb ac-1 did not further enhance plant height.

Biomass production (weight), number of wheat heads 3 ft-1, kernels head-1, kernel weight, and grain production was maximized with 300 lb N ac-1.

No statistically  significant differences were associated with any other N rates.

All assessed wheat biomass and grain parameters, including  kernels head-1, kernel weight, and grain production were numerically greater at 150 ppm P.

 All evaluated P rates were not statistically significantly different for any of the assessed wheat biomass and grain parameters.

 Positive linear relationship was observed for biomass weight and plant height with wheat grain production.