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Rory Maguire

Title Summary Date ID Author(s)
Biochar in Agricultural Systems Aug 20, 2010 442-311
Fertilizer Types and Calculating Application Rates Aug 4, 2009 424-035
Fertilizing Cool-Season Forages with Poultry Litter versus Commercial Fertilizer

The Shenandoah Valley of Virginia and some other regions produce more manure nutrients than local crops need. This manure has traditionally been applied to row crops and overapplication has led to soil-test phosphorus (P) being well above agronomic optimum in many cases. In 2008, it was estimated that nutrient-management regulations now require that approximately 85 percent of poultry litter be applied off poultry farms, as they do not have sufficient land to beneficially recycle their manure nutrients. There is a substantial area of nutrient-deficient forage production in the Shenandoah Valley that could benefit from this poultry litter. This publication summarizes two years of field research on fertilizing nutrient-deficient forages with poultry or commercial fertilizer. It also evaluates split versus single annual applications of nutrients and addresses a common misconception that poultry litter contains weed seeds.

Sep 16, 2009 418-142
Impact of Changing From Nitrogen- to Phosphorus-Based Manure Nutrient Management Plans

Animal manures are a good source of nitrogen (N) and phosphorus (P) for agricultural crops, but they have an imbalance in their N to P ratio, so that if they are applied to meet crop N needs, then P is overapplied. For many years, manures have been applied to meet crop N needs, which has resulted in some soils containing more P than crops require, leading to environmental concerns. Regulations have been developed to limit P losses from manures and soils high in P by moving manure nutrient management from an N basis to a P basis.

Sep 16, 2009 442-310
Importance of Farm Phosphorus Mass Balance and Management Options

Phosphorus is a naturally occurring element that is one of 16 elements essential for plant growth and animal health. Research has documented that applying phosphorus in fertilizers or manure increases crop growth and yield on soils that are below critical agronomic levels, as measured during routine soil testing. Although the economic benefits of phosphorus fertilization on crop production are well-documented, too much of a good thing can be detrimental to the environment. Excessive soil phosphorus is a potential threat to water quality.

Dec 19, 2014 CSES-98P
Laboratory Procedures: Virginia Tech Soil Testing Laboratory May 1, 2009 452-881
Manure Injection in No-Till and Pasture Systems Feb 27, 2013 CSES-22P
Nitrogen Management for White Potato Production

One of the challenges of white potato production, as with any crop, is the efficient management of nitrogen
(N) fertilizer. Excessive N fertilizer applied at or before tuberization can extend the vegetative growth period and delay tuber development, resulting in a lower tuber yield. However, too much N applied later in the season can delay maturity of the tubers, reducing
yield and adversely affecting tuber quality and skin set. Conversely, under-application of N at any point in the season can result in lower tuber yields and reduced profits. Environmental considerations must also be taken into account in N fertilizer management. Nitrogen
is a mobile nutrient in the soil and any excess N has the potential to move off-site via leaching or surface runoff. This is particularly true on the coarse-textured, low-organic matter soils common to the Eastern Shore, the premier potato-producing region in Virginia. These factors make the appropriate N rate and N application timing critical for successful white potato production.

Sep 28, 2009 438-012
Nutrient Management for Small Farms Oct 8, 2010 442-305
Soil Test Note #1 - Explanation of Soil Tests May 1, 2009 452-701
Soil Test Note #2 - Field Crops

Most Virginia soils are acidic and require lime applications at three- to five-year intervals. Maintaining the correct soil pH has several benefits, such as encouraging healthy root development and making sure nutrients in the soil are available to the plant. For example, low pH can cause aluminum toxicity and can decrease phosphorus availability. 

Sep 25, 2014 452-702 (CSES-100P)
Soil Test Note 5: Fertilizing With Manures Aug 19, 2009 452-705
Soil Test Note No.3 - Liming and Fertilization of Cool-Season Forage Crops Aug 28, 2012 452-703 (CSES-16P)
Virginia No-Till Fact Sheet Series Number Three: Manure Injection Nov 16, 2010 3011-1517