Lecture 2. Agricultural Pollution Control in the Baltic Sea with Special Emphasis on Manure Management Prepared by Assoc. Prof. Philip Chiverton, SLU and Göran Carlsson, Head of Research, Swedish Institute of Agricultural and Environmental Engineering

Agricultural Pollution control ”Measures employed to prevent the loss of nutrients (nitrogen and phosphorous) from agricultural land to ground and surface waters” These measures are usually defined in Best Management Practices (BMP).

Best Management Practices 1. Crop rotation Crops are changed year by year in a planned sequence. Crop rotation is a common practice on sloping soils because of its potential for soil saving. Rotation also reduces fertilizer needs, because alfalfa and other legumes replace some of the nitrogen corn and other grain crops remove. Grass and legumes in a rotation protect water quality by preventing excess nutrients or chemicals from entering water supplies. Meadow or small grains cut soil erosion dramatically. Crop rotations add diversity to an operation.

Emerging sugar beet (left) and oil seed rape (right) in rotation near the Baltic sea (background)

2. Conservation Tillage (30 percent or more crop residue left, after planting). Any tillage and planting system that covers 30 percent or more of the soil surface with crop residue, after planting, more of the soil surface with crop residue, after planting, to reduce soil erosion by water. Where soil erosion by wind is the primary concern, any system that maintains at least is the primary concern, any system that maintains at least 1,000 pounds per acre of flat, small grain residue equivalent on the surface throughout the critical wind erosion period. on the surface throughout the critical wind erosion period.

Rows of soybean plants emerge from a field covered with wheat residue from the previous harvest.

3. Permanent vegetative cover Conservation buffers are small areas or strips of land in vegetation, designed to slow water runoff, provide shelter and stabilize riparian areas. Strategically placed in the agricultural landscape, buffers can effectively mitigate the movement of sediment, nutrients, and pesticides within farm fields. Buffers include: contour buffer strips, field borders, filter strips (especially adjacent to rivers, ditches etc.), windbreaks, and wetlands. A small amount of land in buffers can assist producers in meeting both economic and environmental goals

Contour buffer strips of perenneal grass with wider cultivated strips that are farmed on the contour

4. Strip Cropping. Growing row crops, forages, small grains or fallow in a systematic arrangement of equal width strips across a field. o Reduces soil erosion from water and transport of sediment and other water-borne contaminants o Reduces soil erosion from wind o Protects growing crops from damage by wind-borne soil particles particles

Strip cropping – growing crops in a systematic arrangement of strips across the field to reduce soil erosion, reduce particulate emissions into the air and improve water quality.

Best Management Practices 1. Crop rotation Crops are changed year by year in a planned sequence. Crop rotation is a common practice on sloping soils because of its potential for soil saving. Rotation also reduces fertilizer needs, because alfalfa and other legumes replace some of the nitrogen corn and other grain crops remove. Grass and legumes in a rotation protect water quality by preventing excess nutrients or chemicals from entering water supplies. Meadow or small grains cut soil erosion dramatically. Crop rotations add diversity to an operation.