The International Plant Nutrition Institute has developed a framework for thinking about fertilizer best management practices (BMPs) called 4R Nutrient Stewardship. Fully utilizing the 4 R’s will:
- Help minimize pollution of surface and ground water from fertilizers or manure.
- Supply nutrients to the plants when they are needed, therefor increasing nutrient use efficiency.
- Build and maintain the physical, chemical and biological condition of the soil.
- Save money by reducing input costs and increasing production!
The scientific principles of the 4R framework are:
- Right Source – Ensure a balanced supply of essential nutrients in plant available forms. Consider both organic and synthetic sources, and the characteristics of specific products. Possible plant nutrient sources include manure, compost, cover crops, organic fertilizers, and synthetic fertilizers.
- Right Rate – Choose an application rate based on soil nutrient supply and plant demand. This varies by season, crop, previous nutrient applications, and expected yield. Over application of nutrients is a waste of time and money, and causes nutrient pollution of ground or surface water.
- Right Time – Assess and make decisions based on the dynamics of plant uptake, soil supply, nutrient loss risks, and field logistics. Do not apply fertilizer if more than a ½ inch of rain is forecasted within the next three days. Careful timing of applications during the growing season can help improve nutrient use efficiency. Two or three or three small applications rather than one large application will also improve nutrient use efficiency. This is good for both the environment and your bank account!
- Right Place –Consider root-soil interaction and the movement of nutrients within and across soil to manage crop needs and limit potential losses from the field. Do not spread manure, compost, or fertilizer within 25 feet of a creek, wetland, or pond. Incorporate manures and fertilizers within 12 hours if possible to prevent nitrogen loss to the atmosphere as ammonia gas. Incorporating compost into the soil after application will provide more immediate soil quality benefits than using it as mulch or top-dressing.