Virginia Manure Test Summaries
Accurate and up-to-date manure tests are an important basis for nutrient management planning with livestock manures. The Virginia Nutrient Management Standards and Criteria utilizes the following average total Kjeldahl nitrogen (TKN), ammonium nitrogen (NH4), phosphate (P2O5), and potash (K2O) values for manure tested in the Virginia Tech Manure Testing Laboratory during 1989-92:
|Table 1. Average Values for Manure Tested in Virginia, 1989-921|
|Manure type2||TKN||NH4||P2O5||K 2O|
|Semi-solid Dairy (46)||10.54||3.16||6.12||8.67|
|Liquid Dairy (434)||22.61||9.57||12.07||18.92|
|Semi-solid Beef (18)||12.79||2.57||6.67||11.30|
|Dry Broiler Litter (254)||62.58||11.75||62.12||28.57|
|Dry Turkey Litter (85)||61.75||15.18||63.68||24.36|
|Layer or Breeder (54)||36.46||8.98||65.06||24.22|
|Liquid Poultry (14)||51.08||32.95||41.01||30.53|
|Mixed Swine (76)||41.13||26.93||29.75||18.18|
|Swine Lagoon (109)||10.14||5.34||5.68||5.72|
Manure testing for Virginia nutrient management plans is now conducted in a Maryland laboratory. For Virginia farmers, the Virginia Department of Conservation and Recreation (DCR) currently subsidizes manure testing. Summary results from 1998-99 manure tests indicate that some manure average nutrient values are significantly different than earlier test results.
|Table 2. Average Values for Virginia Manure Tests 1998-991|
|Dairy or beef semisolid w/o bedding (27)||11.47||2.65||6.48||8.28|
|Dairy or beef solid w/ bedding (27)||18.73||2.78||14.87||17.93|
|Dairy or beef liquid (178)||21.76||9.44||10.61||17.32|
|Poultry solid w/o litter (53)||54.01||15.84||57.33||42.01|
|Poultry deep pit (5)||50.24||14.35||50.39||27.14|
|Poultry solid w/ litter (761)||71.61||13.53||58.17||43.40|
|Swine fresh (11)||16.23||5.01||23.51||5.60|
|Swine liquid (157)||10.19||7.57||6.40||7.98|
Livestock manure categories differ between the earlier Virginia Manure Testing Laboratory results and the current Maryland lab results. For example, dairy and beef liquid manure is not distinguished on the newer results, nor is broiler litter distinguished from turkey litter.
Among those manure types with more than 100 samples, some nutrient concentrations are markedly different in the 1998/99 manure samples than in the earlier results. Liquid dairy/beef manure phosphate in the 1998/99 samples is 12% lower than reported in 1989/92. Swine lagoon ammonium is 42% higher than the earlier tests, phosphate is 13% higher, and potash is 40% higher. Poultry solid manure with litter is 15% higher than the weighted average of broiler and turkey litter in the earlier tests, ammonium concentration is 7% higher, phosphate is 7% lower, and potash is 58% higher.
Producers may refer to the average nutrient values tests listed in DCR's Virginia Nutrient Management Standards and Criteria (Table 1) for estimating the amount of manure to be applied to a field, but the most accurate result comes from using current/recent manure test results from the producing farm. Manure can be a cost-effective nutrient source for crop, hay, and pasture production. Properly applied manure can also improve organic matter, tilth, soil aeration, and water-holding capacity. Proper handling and field application methods, application timing, and application rate are necessary to avoid potential damage to water quality.
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