Agricultural Drainage Well Users Assisted through Integrated Crop Management

J. Kennicker, A. Rieck-Hinz and G.A. Miller
Department of Agronomy, Iowa State University

Introduction

In 1994, ISU Extension Staff and the Iowa Department of Agriculture and Land Stewardship introduced an Integrated Crop Management (ICM) program targeted to areas of the state served by agricultural drainage wells (ADWs). The ICM program is designed to assist producers who own or operate land which drains water into an ADW and who are subject to impending state administrative rules regarding the continued use of the ADWs.

ICM is a total crop production and protection program that assists cooperators in adopting management practices to increase efficiency and profitability while minimizing environmental impacts on water quality. The ICM program provides an individualized agronomic plan that evaluates soil, nutrient, crop, pest and tillage management through the use of field-by-field information. At present, the ICM program includes cluster areas in Floyd, Humboldt, Pocahontas and Wright counties (Table 1).

* this includes 758 acres enrolled in Webster County

Objectives

The project objectives include: 1) recruit producers willing to participate in an ICM program designed for ADW owners and users, 2) assist cooperators in learning and adopting ICM practices, 3) assist cooperators in maximizing efficiency and profitability of their resources while minimizing impacts on the environment, and 4) help cooperators to institutionalize the ICM process so that producers continue to use ICM in future crop years.

Materials and Methods

ADW owners and users were invited to recruitment meetings. Producers interested in joining the ICM program were identified and scheduled for one-on-one meetings to document cropping practices from the past cropping years and plan the upcoming season. Project staff assists cooperators in recording inputs, interpreting test results and analyzing related data. The ICM program includes services to help cooperators manage practices such as soil sampling for soil fertility management, establishing yield goals, manure nutrient management, equipment calibration, field scouting for weeds, disease and pests, identifying changes in cultural practices and making recommendations in variety selection. Record keeping and recommendations are provided to the producer on a field-by-field basis.

Results and Discussion

Disease and Insect Management

Soybean cyst nematode(SCN)infestations have become an increasing concern in soybean production in Iowa. In 1997, SCN samples were taken and analyses were delivered. Recommendations were made for 17 analyses ranging from 0 to high levels of SCN for more than 1,200 acres. Planting an SCN-resistant variety versus a susceptible variety in a heavily infested field could mean a yield increase of 5 bu/acre. There would be a income increase of $35.00/acre (at $7.00/bu). For the estimated 1,200 acres, the total income increase could be $42,000.00. SCN-resistant varieties can suppress SCN reproduction and provide increased yields relative to susceptible varieties. Integrated management, early detection through scouting, and recommended nonhost crop rotation and resistant varieties can maximize yields and lower reproduction of SCN (see photo 1).

Weed management

As a guide in reducing potential risk to the water resources, pesticide selection, rate reductions, application methods (timing and banding), and cultural control methods (cultivating) are recommended for weed management. These practices have the potential to improve water quality. In the spring of 1998, approximately 1,777 acres were planted to Round-up Ready soybeans in the project area. As a pesticide, Roundup Ultra adheres tightly to the soil particles. Roundup Ultra has a very low leaching potential and a moderate loss to surface runoff compared to other pesticides.

Nutrient Management

In preparation of Crop Year 1998 more than 2,700 acres were sampled for soil test analysis by soil map unit and landform. Recommendations were made to cooperators for fertility management. On many of the acres sampled, the interpretation of the lab analysis called for no additional P or K (Table 2). As an example, one cooperator had soil sample test results on 256 acres that were high to very high for P and K. The cooperator did not need to apply P or K for two years on the 256 acres. If the cooperator had applied a normal two-year fertilizer maintenance for a corn soybean rotation of 0 +92 +120, the fertilizer cost (P at $0.26/lb., K at $0.14/lb.) on 256 acres would have been $10,424.32. Working one-on-one with cooperators, excessive fertilization may be prevented, saving the cooperator money (see photo 2).

Conclusions

Producers were recruited and cooperators continue to participate in the ICM program. The ICM Program provides assistance for the development of nutrient and pest management plans, establishment and maintenance of field-by-field records and education of requirements and responsibilities of ADWs users. The ICM program has successfully shown increases in profitability. The ICM program encourages cooperators to adopt practices to maximize efficiency and profitability of their resources while accounting for environmental impacts, such as water quality.

This project is funded by Division of Soil Conservation of the Iowa Department of Agriculture and Land Stewardship, cooperative agreement number ADWUA-98-01.