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Effects of various soil amendments on soil test P values. David Brauer, Glen Aiken, Dan Pote ARS/USDA, Booneville AR S.J. Livingston, L.D. Norton ARS/USDA, W. Lafayette IN T.R. Way and J.H. Edwards ARS/USDA, Auburn, AL. Acknowledgements. Additional funds were provided by:
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Effects of various soil amendments on soil test P values David Brauer, Glen Aiken, Dan Pote ARS/USDA, Booneville AR S.J. Livingston, L.D. Norton ARS/USDA, W. Lafayette IN T.R. Way and J.H. Edwards ARS/USDA, Auburn, AL
Acknowledgements • Additional funds were provided by: • Southern Plains Area Office/ARS • U.S. Poultry and Egg Association
Rationale and Objectives • Rationale • Manure applications from concentrated animal feeding operations have increased soil P levels • P transport from agricultural land to surface water is undesirable • Objectives • Evaluate various amendments to decrease soil test values for P
Farm History- Kurten Site • Farm occupies 200-300 acres • Dairy operation- Post WWII era (30 years) • Hen laying operation since early 1980’s • 500,000 birds • 30-35 Mg of wet manure produced daily (70% moisture)
Kurten TX site: Climate • Rainfall • About 900 mm of annual rainfall • About 100 mm occurs in July and August, thus leading to low soil moisture • Annual Average temperature • About 20 C
Kurten Site- Soil Characteristics • Zulch fine sandy loam (thermic udertic Paleustalfs) • Chemical characteristics Ap horizon • Mehlich III P ~1,500 mg/ kg • Bray-1 P ~3,000 mg/ kg • DRP (25:1) 50 mg/ kg • Soil Ca ~5,500 mg/ kg • Soil pH 7.8
Soil amendments at Kurten Site • Gypsum (2 rates, 1.5 and 5 Mg/ ha) • Alum (1.4 Mg/ ha) • Waste paper (24.4 Mg/ ha) • Waste paper plus Gypsum • Waste paper plus Alum • Waste paper plus Alum and Gypsum
Experimental Protocol • Amendments applied annually 1999 to 2001 in March. • Soil samples (0-7.5 cm and 7.5-15 cm) collected in July/August from 1999 to 2004. • Bray-1 P and DRP (25 ml water per 1 g soil). • DRP solutions analyzed for Ca-readily reactive Ca.
Booneville Experiment • Ability to change soil P levels with waste paper • Leadvale silt loam • Low P soil (<60 mg P/kg Bray-1 P values) • 3 rates of waste paper (22, 44 or 88 Mg/ha to supply 90, 170 or 350 kg Al/ha)
Conclusions • Gypsum can reduce runoff and DRP when soil P values are very high • Low soluble, reactive Ca • Ca added in amounts equal to Mehlich P • Decreases in runoff P with amendments • Maybe associated with changes in soil structure