414-1 Quantifying Long-Term Availability of Phosphorus in Swine Manure.

Poster Number 411

See more from this Division: ASA Section: Environmental Quality
See more from this Session: Nutrients and Environmental Quality

Wednesday, November 18, 2015
Minneapolis Convention Center, Exhibit Hall BC

T.Q. Zhang, Harrow Research and Development Centre, Agriculture & Agri-Food Canada, Harrow, ON, Canada, Xianjun Hao, Greenhourse and Processing Crops Research Center, Agriculture and Agri-Food Canada, Harrow, ON, Canada, Chin Tan, Agriculture & Agri-Food Canada, Harrow, ON, CANADA, Tom Welacky, GPCRC, AAFC, Harrow, ON, Canada and Yutao Wang, Agriculture & Agri-Food Canada, Guelph, ON, CANADA
Abstract:
Recent research advances indicate that legacy phosphorus (P) in soils can be usable by crops in the following years, while its availability varies depending on P source and the accompanying components. Long-term availability of manure/fertilizer P must be quantified on a source-specific base to develop economically and environmentally sound BMPs. We conducted an 8-year study to evaluate the effects of repeated application of chemical fertilizer and three forms of swine manure (liquid, LM; solid, SM; and liquid manure compost, MC) on crop yield, P uptake, and changes in soil test P (i.e. Olsen P) under corn-soybean rotation in a clay loam soil. Phosphorus from each source was added to the corn phase at 100 kg P ha-1 yr-1. Manure P source coefficient (PSC) was calculated in equivalency to the chemical fertilizer. Corn yield over the 8-year period followed the order of LM>SM≥MC, while soybean yield did not differ amongst the three forms of swine manure. Similar patterns were observed for total P uptake and grain P removal for both corn and soybean. Level of soil test P increased with year of application, but the incremental varied with the source of P added. When taking crop P removal and the increases of STP into account, each unit increase of STP required 12.2, 9.8, 16.1 and 10.7 kg ha-1 net P addition for CF, LM, SM, and MC, respectively. The calculated manure PSC values were 1.10, 1.07 and 1.02 for LM, SM, and MC, respectively, indicating that long-term P availability of swine manures was about identical to that of chemical fertilizer, with some potential for mobilizing indigenous P in soil, regardless of the form. Long-term cumulative P agronomy efficiency, defined as grain yield produced with each kg net P input in a given year-period since its 1st application, decreased linearly with increases in net P input over time, regardless of crop species and P source. P-based manure application must be optimized on a manure-form specific base. Long-term P management must take the effect of legacy P into consideration.

See more from this Division: ASA Section: Environmental Quality
See more from this Session: Nutrients and Environmental Quality

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