October 22, 2007

Contact: Dr. Quirine M. Ketterings, Cornell University, 607-255-3061;
Joe Lawrence, Nutrient Management Spear Program, 607-255-3061

Four New Crop Management Resources Online for NNY farmers

The Northern New York Agricultural Development Program website at www.nnyagdev.org is providing area farmers with four new resources on the interaction of soils, nutrients and crops. The publications are part of a series from Cornell University�s Department of Crop and Soil Sciences and the Cornell Nutrient Management Spear Program. The fact sheets � found in the Agricultural Environmental Management section of the website at www.nnyagdev.org � are designed to help farmers make decisions about field crop management, including which crops to plant, when, and on what fields based on the availability of essential nutrients, fertility management and good stewardship practices.

The How Quickly Will Soil Test P Increase? fact sheet reports research on the effects of how manure and fertilizer applications affect the changes in soil test phosphorus (P) levels in farm soils to help producers learn how long it may be before soil test P levels will reach a level at which alternative manure applications sites must be found. For example, if manure is surface applied and not incorporated into the soil, the ammonia portion of manure nitrogen(N) is lost. Sand affects the optimal 2:1 N to P ratio, thus surface application of manure to meet crop N needs requires higher manure application rates leading to a phosphorus application that can be twice as much as what the plants will be able to remove through harvest. This increases soil test P over time. The study also shows how quickly soil test P levels rise for different soils.

The Phosphorus Removal by Field Crops fact sheet shows how to estimate manure and fertilizer application limits if the P Index is high, based on the projected removal of phosphorus by a crop. The P Index requires producers to limit phosphorus application to the estimated level of crop removal when the risk for a farm is rated High. No P in any form may be applied to fields rated Very High.

The Soybean Nitrogen Credits fact sheet provides the background behind an adjustment in Cornell guidelines for applying a soybean nitrogen (N) credit (an estimate of how much N remains in the soil for crop uptake) of 20 to 30 lbs of nitrogen per acre for corn production only during the first year of corn planted after a crop of soybeans. This rate of application is lower than for corn planted after corn. In other words, the optimum economic N application rate for corn after soybeans can be lowered by 20-30 lbs of N per acre thus saving farmers money for N fertilizer not purchased.

The Late Season Stalk Nitrate Test fact sheets provides the sampling and submission procedure for evaluating the nitrogen (N) supply available for corn during the past growing season. The stalk nitrate test results are useful in planning for adjustments in the fertilization program for the next year�s crop. This fact sheet notes that multiple year testing is essential for success with using this test.

Ongoing NNY soils research will add to knowledge base
Studies currently underway using 15 Northern New York non-calcareous (without limestone) soils and ten different P sources will determine the impact of the type of fertilizer (ammonium or calcium based, liquid or granular) used with manure separation and-or chemical treatment (alum or aluminum chloride) on plant-available phosphorus in the soils.

Links to these and other fact sheets providing valuable information and recommendations specific to the Northern New York region are found on the Northern New York Agricultural Development Program website at www.nnyagdev.org. The farmer-led Northern New York Agricultural Development Program provides funding for research, education and outreach to assist agricultural producers improve on-farm efficiencies and profitability.