Avoiding Nutrient Movement in the Landscape

We studied using ‘programmed decisions’ in a long-ago business management class to streamline responses: if this happens, then do X, Y, and Z. Of course, nothing ever happens according to plan. Planning reduces problems down the road however, we cannot predict everything that will happen at the agricultural-environment interface.

Severe weather timing and intensity, temperature changes, or even insect pressure affect nutrient management outcomes, but we cannot succumb to frustration at the start. Nutrient and sediment movement on the landscape can be minimized with planning and preparation using “avoiding” Best Management Practices (BMPs).

Animal diet control options such as low phosphorus (P) corn hybrids, dietary management, or feed additives that manage the P entering environmental systems are promising technologies, however this note will focus on soil-oriented P and nitrogen (N) fertility and management.

Any discussion of environmentally conscious nutrient management for agronomic crops begins with the 4 R’s: Using the Right Amount of the Right Fertilizer, at the Right Time in the Right Place.

The Right Amount of fertilizer depends on whether you really need to add P, or in our warm, humid Mississippi environment, a realistic understanding of your crop N needs Nitrogen soil testing in Mississippi. Soil P management begins with a well-designed soil testing program for P and other nutrients, and soil acidity using a reputable laboratory for analysis. Sometimes, zero P fertilizer is the right amount for the current crop. Pay close attention to the recommendation philosophy of the laboratory or consultant, for more information about different recommendation systems go to Soil Test Recommendations.

Choosing the Right Fertilizer for the situation requires doing your homework. Fertilizer properties affect both agronomic and environmental fates. In addition to movement through the landscape in runoff or leaching, N can be lost to volatilization and denitrification. Placing fertilizers in the Right Place requires knowledge of fertilizer properties. In some situations, band placement will optimize use efficiency and reduce potential loss through interaction with soil components. Applying at the Right Time increases use efficiency and decreases the exposure time for potential nutrient movement.

If you have found the Right Rate of N for your situation, some guidelines for using the Right Fertilizer, at the Right Place, at the Right Time for optimizing corn N management in Mississippi are here: Optimizing Corn N Fertilizers.

Soil management to avoid pollutant movement in the landscape resembles managing for soil carbon enhancement: BMPs for soil C storage. Keeping soils covered as much as possible, minimizing tillage, using diverse crop rotations, including cover crops, reduces erosion; these practices also reduce nutrient movement either in runoff or leaching.

As previously noted in The ACT for Agriculture, choosing the applicable soil management practices for avoiding, controlling, or trapping nutrient or sediment movement requires site-specific decisions. Factors to consider include the soil resource (Using Soil Surveys), local climate, available capital, equipment, and human resources, and perhaps, most importantly, the goals and objectives of both the farm as a business entity, and the people making the decision.

MSU South Farm