Research and extension efforts in this area include assessment of P supply from animal manures, soil P testing for manured soils, environmental soil P testing, relationships between P losses to surface water supplies and soil P levels or manure/fertilizer management, and development of a P risk index in cooperation with other researchers and agencies. Trials are conducted in cooperation with producers and/or other researchers, and use a conventional plot methodology or a strip-trial method in conjunction with GPS and yield monitors.

The research work in this area include evaluation of various placement methods for P and K fertilizers for corn and soybean managed with conservation tillage and chisel-disk systems, study of relationships between grain yield and early crop growth or nutrient uptake , and soil sampling methods. The placements include application of dry (granulated) fertilizers broadcast, deep banded (about 5-7 inches deep), banded with the planter (2 inches beside and below the seeds), and strip tillage alone (for no-till). Trials are conducted using a conventional plot methodology or a strip-trial method in conjunction with GPS and yield monitors.

The work with liquid starter fertilizers focuses on evaluating the effect of starter mixtures applied with the planter either in the furrow (pop-up) or beside and below the seeds (2 by 2) for corn grown with no-till or chisel-disk tillage. Most trials conducted in cooperation with producers are based on a conventional plot methodology or a strip-trial method in conjunction with GPS and yield monitors. The main objectives of the research are to study the role of in-the-furrow and "2 by 2" starter fertilization as a complement to the less expensive broadcast method, and relationships between grain yield and starter-enhanced early crop growth or nutrient uptake. An additional project developed in cooperation with a crop management specialist studies the interactions of starter fertilization, corn row spacing, hybrids, and planting date. The foliar fertilization work focuses on soybean response to early application of mixtures of various nutrients (N-P-K and micronutrients).

Major efforts focus on studying soil test and yield variability in corn and soybean fields, comparing soil sampling methods (grid sampling, zone sampling), comparing fixed and variable rate application of P and K fertilizers and liquid swine manure, and developing on-farm research/demonstration methods based on precision agriculture technologies. Current projects include field-scale strip trials conducted in cooperation with producers and coops in major agricultural areas of the state.

Field response trials in research farms and producers’ fields are conducted to improve soil-test P and K interpretations and fertilizer recommendations. The work for P emphasizes improving interpretations for the Bray-1, Olsen, and Mehlich-3 tests and evaluations across a wide range of soil pH and calcium carbonate content. Work for K emphasizes study of the ammonium acetate and Mehlich-3 tests in various soil associations and evaluation of a test seemingly less affected by variations in soil moisture. Much of this work is coordinated with work conducted for the precision agriculture and manure and environmental P issues.