Submitted to: Natural Resources Research Update (NRRU)
Publication Type: Research Technical Update
Publication Acceptance Date: 8/27/2008
Publication Date: 8/27/2008
Publication URL: http://hdl.handle.net/10113/8050
Citation: Wienhold, B.J. 2008. Spatial and temporal variability affect soil microorganism activity in high production corn systems. Natural Resources Research Update (NRRU). Update #230685. Available at: http://hdl.handle.net/10113/3951, http://hdl.handle.net/10113/8049, http://hdl.handle.net/10113/8050 and http://hdl.handle.net/10113/3051. Interpretive Summary:
Technical Abstract: Traditional corn feed contains phosphorus (P) in a form that monogastric animals such as swine and poultry can not use efficiently. Poor use efficiency of feed P requires P supplements be added to the diet and results in manure having a high P content. Land application of this manure, at rates to meet the nitrogen needs of a crop, results in accumulation of P in soils. Elevated soil P concentration increases the potential for environmental contamination. Low phytate corn contains similar amounts of P in a form that can be utilized more efficiently by monogastric animals. Laboratory and field studies were conducted to compare P content and composition, changes in soil properties, and crop availability of land applied P for slurry from swine fed a traditional corn diet to that of slurry from swine fed a low phytate corn diet. Slurry from low phytate corn diets contained 40% less total P and had a higher N:P ratio (4.5 vs. 3.3) than slurry from traditional corn diets. A sequential extraction procedure determined that the composition of P in the two slurries was similar (Wienhold and Miller, 2004). Land application of these two slurry types improved soil properties affecting crop production. When applied at rates to meet crop N requirements soil P accumulation was lower for low phytate slurry than for traditional slurry (Wienhold, 2005). Surface application of these two slurry types resulted in availability of 70% of applied N and 100% of applied P while incorporation of the slurry reduced availability to 40% of applied N and 60% of applied P (Paschold et al., 2008a). No-tillage, rainfed sorghum and conventionally tilled, irrigated corn grain P utilization was similar for inorganic fertilizer and the two manure sources (Paschold et al., 2008b). Availability and crop N and P utilization from low phytate slurry and traditional slurry was similar and nutrient guidelines developed for traditional slurry should also apply for low phytate slurry. Use of low phytate feed is a technology that swine producers can use to reduce the P content of slurry. Reducing the P content of slurry will slow the rate of P accumulation in slurry applied soils and reduce the amount of land needed for slurry disposal. Availability and crop utilization of P in low phytate slurry is similar to that for traditional slurry and nutrient management guidelines for traditional slurry should be followed. Publications contributing to the NRRU Release shown above: Grigera, M.S., R.A. Drijber, K.M. Eskridge, and B.J. Wienhold. 2006. Soil microbial biomass relationships with organic matter fractions in a Nebraska corn field mapped using apparent electrical conductivity. Soil Science Society of America Journal 70:1480-1488. Grigera, M.S., R.A. Drijber, and B.J. Wienhold. 2007. Redistribution of crop residues during row cultivation creates a biologically enhanced environment for soil microorganisms. Soil and Tillage Research 94:550-554. Grigera, M.S., R.A. Drijber, and B.J. Wienhold. 2007. Increased abundance of arbuscular mycorrhizal fungi in soil coincides with the reproductive stages of maize. Soil Biology and Biochemistry 39:1401-1409. Grigera, M.S., Drijber, R.A., Shores-Morrow, R.H., and Wienhold, B.J. 2007. Distribution of Arbuscular Mycorrhizal Biomarker C16:1cis11 Among Neutral-, Glygo-, and Phospho-Lipids Extracted from Soil During the Reproductive Growth of Corn. Soil Biology and Biochemistry 39:1589-1596.