Interactions between Soil Texture and Placement of Dairy Slurry Application: II. Leaching of Phosphorus Forms

Abstract

Managing phosphorus (P) losses in soil leachate folllowing land application of manure is key to curbing eutrophication in many regions. We compared P leaching from columns of variably textured, intact soils (20 cm diam., 20 cm high) subjected to surface application or injection of dairy cattle (Bos taurus L.) manure slurry. Surface application of slurry increased P leaching losses relative to baseline losses, but losses declined with increasing active flow volume. After elution of one pore volume, leaching averaged 0.54 kg P ha(-1) from the loam, 0.38 kg P ha(-1) from the sandy loam, and 0.22 kg P ha(-1) from the loamy sand following surface application. Injection decreased leaching of all P forms compared with surface application by an average of 0.26 kg P ha(-1) in loam and 0.23 kg P ha(-1) in sandy loam, but only by 0.03 kg P ha(-1) in loamy sand. Lower leaching losses were attributed to physical retention of particulate P and dissolved organic P, caused by placing slurry away from active flow paths in the fine-textured soil columns, as well as to chemical retention of dissolved inorganic P, caused by better contact between slurry P and soil adsorption sites. Dissolved organic P was less retained in soil after slurry application than other P forms. On these soils with low to intermediate P status, slurry injection lowered P leaching losses from clay-rich soil, but not from the sandy soils, highlighting the importance of soil texture in manageing P losses following slurry application.

Long-term trends in nutrient concentrations in Polish coastal rivers

“…(2015) 1e10 8 solubilization of its compounds (Liu et al, 2012). Application of organic fertilizers may constitute a direct risk of nutrient losses, especially if surface-applied and/or applied during periods of high rainfall which increase the runoff potential (Glaesner et al, 2011;Liu et al, 2012). The essential role of organic fertilizer application on nutrient losses to surface water, and consequently on water quality changes was confirmed in our studies.…”

Persistence and Leaching Potential of Microorganisms and Mineral N in Animal Manure Applied to Intact Soil Columns

“…The extent of soil-slurry mixing during application is of fundamental importance in controlling the leaching potentials, because a better incorporation of slurry into the bulk soil can remove a major portion of contaminants from active macropore flow paths (21). On the other hand, greater redistribution of slurry constituents in a soil with few preferential flow paths may increase the interaction between matrix flow and contaminants and, hence, leaching.…”

“…On the other hand, in structured soil this filtering effect can be severely reduced by preferential flow and macropore flow (13,14), and microorganisms may move with runoff or infiltrating water as free cells and/or attached to soil and manure particles (15,16,17). While the environmental fate of manure-borne contaminants has received attention in the past (5,11), there are recent developments in manure management techniques for improved nutrient use efficiency and odor control, including solid-liquid separation (18,19) and field application methods, that may alter the environmental fate of some contaminants (20,21).…”

“…Slurry is usually applied to agricultural fields by surface application or, increasingly, by subsurface injection at 6-to 10-cm soil depth to reduce nuisance odor and NH 3 volatilization from the applied slurry (23,24,25). These two application methods may represent different risks for leaching of nutrients and microorganisms as a result of the difference in slurry-soil contact (21,26,27).…”

The effect of anaerobic baffled reactor effluent on nitrogen and phosphorus leaching from four soils in a laboratory column experiment

“…Leaching in the upflow columns showed that coarse-textured soils leached more P than fine-textured soils, which may be attributed to their high saturated hydraulic conductivity and active flow volume, which is inversely related to the clay content (Glaesner et al, 2011). Unlike the nitrate leaching, the P leaching in down-flow columns from the Se (clay loam) and Ia (loam) soils was higher than from the sandier soils, which agrees with the findings of Djodjic et al (1999) who showed that, under preferential flow and low active PVs, clay soils leached more P than sandy soils.…”