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ARS Home » Northeast Area » Orono, Maine » New England Plant, Soil and Water Research Laboratory » Research » Publications at this Location » Publication #185793
Title: ROOT GROWTH EFFECTS ON SOLUBLE C AND P IN MANURED AND NON-MANURED SOILS

Author
item PIPER, A - UNIV OF MAINE
item ERICH, M - UNIV OF MAINE
item PORTER, G - UNIV OF MAINE
item Griffin, Timothy

Submitted to: Plant and Soil
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/1/2006
Publication Date: 7/15/2006
Citation: Piper, A., Erich, M.S., Porter, G.A., Griffin, T.S. 2006. Root growth and manure effects on soluble C and P in soils. Plant and Soil Journal. 283:353-366.

Interpretive Summary: There is limited research on relationships between root characteristics and soil chemical properties and processes. The objectives of this study were to measure soluble organic matter concentration in soil under different rotation crops, and to assess the relationship between soil phosphorus (P) and soluble carbon (C). Roots and soil were collected plots containing potato, barley, soybean, and mixed forage (alfalfa and timothy), to determine root length density (RLD) and soluble C and P concentrations. Half of the sampled plots were amended with beef manure and half were not amended. Barley and forage consistently had higher RLD than potato or soybean, and also typically had higher concentrations of soluble C in the soil. However, there was no straight-line relationship between root length and soluble C in the soil. Soil P levels were typically higher in barley and forage crops. However, linear correlations between soluble C and soluble P were only significant at two of the five sampling dates. The significant relationships were noted for manure-amended soils, indicating that the manure is increasing levels of both C and P and enhancing the relationship between these two variables. Although the lack of significant correlations between RLD and soluble C makes it impossible to conclude that root length is a predictor for soil C levels, it does appear that soluble C can significantly increase P solubility. Therefore, cropping systems that promote increased soluble soil C levels may enhance P bioavailability.

Technical Abstract: There is limited research on relationships between root characteristics and soil chemical properties and processes. The objectives of this study were to measure soluble organic matter concentration in soil under different rotation crops, and to assess the relationship between P concentration and soluble C soil concentration. Roots and soil from potato, barley, soybean, and mixed forage (alfalfa and timothy) were sampled from a long-term field experiment in Presque Isle, ME, during the summers of 2003 and 2004 to determine root length density (RLD) and soluble C and P concentrations. Half of the sampled plots were amended with beef manure and half were not amended. Barley and forage consistently had higher RLD than potato or soybean. Barley and forage also typically had higher concentrations of soluble soil C. When correlating RLD to soluble C, none of the relationships were significant. As with soil C, soluble soil P levels were typically higher in barley and forage crops. However, linear correlations between soluble C and soluble P were only significant at two of the five sampling dates. The significant correlations were noted for manure-amended soils, indicating that the manure is increasing levels of both C and P and enhancing the relationship between these two variables. Although the lack of significant correlations between RLD and soluble C makes it impossible to conclude that root length is a predictor for soil C levels, it does appear that soluble C can significantly increase P solubility. Therefore, cropping systems that promote increased soluble soil C levels may enhance P bioavailability.