Nutrient Management Laws for water

Though many states currently do not have nutrient management laws, many states on the east and west coast are beginning to enact them. Maryland has recently instated a program that deserves a quick look to understand what a nutrient management system is and how it affects your water supply.

The Maryland Nutrient Management law has been passed and will require that all managed landscapes of 3 acres or greater and State property must follow University of Maryland Cooperative Extension fertility recommendations. Maryland residents record all use of fertilizer. These Records must be kept for at least 3 years and include soil test results, amount of nutrient applied to the land and to the plants, timing and rate of application, and the nutrient content of any fertilizer applied.

How do I start a nutrient management program? Apply slow release fertilizers at a rate between 1-3 lbs. of actual nitrogen per 1000 sq. ft. per application and do not exceed 4 pounds of actual nitrogen per 1000 sq. ft. annually. Quick release fertilizers should only be used when the objectives of fertilization cannot be met with slow release fertilizer. Use rates between 1 and 3 lbs. of actual nitrogen per 1000 sq. ft. per application and do not exceed 3 lbs. of actual nitrogen per 1000 sq. ft annually.

Be wise in choosing your fertilization area. Define the fertilization area prior to application. Consider root accessibility, root location, fertilization objectives, and plant species. Fertilize under the drip line of the trees and shrubs. For some aggressively rooting plants such as Norway maple and pin oak, an area 1.5x the drip line area can be fertilized. Do not include inaccessible surfaces when determining the rate of application. Calculate overlapping of fertilization areas once.

Calculation the area for fertilizer application:

A crabapple with a 20-ft branch spread will receive fertilizer.

A circle area is calculated as Area =3.14 R2.

The radius is 10 ft. 102 X 3.14 = 314 sq. ft.

If the tree is to receive 2 lbs. of actual N/1000 sq. ft. then ...

2 lbs. of actual N/1000 sq. ft = x lbs. of N 1000 sq. ft. 314 sq ft x 1000 = 2 X 314 x 1000 = 628 x 1000 = 628 1000 x = .628 actual N/1000 sq/ft is applied to 314 sq. ft.

Application rate of fertilizer per tree status: Status Rate/Year Newly planted 0 - 1 lb. N/1000 ft2/year Established plants 2- 4 lb. N/1000 ft2/year Maturing trees 1 lb. N/1000 ft2/year

Choose the right fertilizer application methods.

For surface application, uniformly distribute fertilizer within the defined area to be treated. Do not make surface applications where surface runoff is likely to occur. Where turf or ground cover exists, subsurface fertilization should be the preferred method of fertilization. For sub-surface dry fertilization, evenly space holes within the defined fertilization area. Holes should be 2 to 4 inches in diameter, spaced 12 to 36 inches apart and 4 to 8 inches deep. The fertilizer should be evenly distributed among the holes. The fertilizer shouldn't be closer than 2 inches to the soil surface. For subsurface liquid fertilizer injection, evenly distribute the injection sites within the fertilization area. For liquid injection systems, the pressure should not exceed 200 lbs. per square inch. Fertilizer should be evenly distributed between holes. Foliar applications, injections, or fertilizer implants should only be used when soil application of fertilizer is impractical or ineffective in achieving fertilization objectives.