Returning degraded soils to productivity: an examination of the potential of coarse woody amendments for improved water retention and nutrient holding capacity

Authors: MENZIES PLUER, E.G. - Cornell University; SCHNEIDER, R.L. - Cornell University; MORREALE, S.J. - Cornell University; Liebig, Mark; LI, J. - Ningxia Axcademy Of Agriculture And Forestry Sciences; LI, C.X. - Chongqing University; WALTER, M.T. - Cornell University

Submitted to: Journal of Water Air and Soil Pollution
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/19/2019
Publication Date: 1/2/2020
Citation: Menzies Pluer, E., Schneider, R., Morreale, S., Liebig, M.A., Li, J., Li, C., Walter, M. 2020. Returning degraded soils to productivity: an examination of the potential of coarse woody amendments for improved water retention and nutrient holding capacity. Journal of Water Air and Soil Pollution. 231:15. https://doi.org/10.1007/s11270-019-4380-x.
DOI: https://doi.org/10.1007/s11270-019-4380-x

Interpretive Summary: Soil restoration strategies are urgently needed for severely degraded soils. Incorporation of coarse woodchips has been proposed to restore degraded soils, but there is limited information to guide use of woodchips to enhance important soil functions. Therefore, field and laboratory studies were undertaken to quantify the effects of coarse woodchips on water and nutrient retention for degraded, sandy soils. Coarse woodchips incorporated into the soil increased water holding capacity by 16% in the field and 18% in the laboratory and was attributed to absorption of water by the woodchips. Soluble nutrient losses of nitrogen and phosphorus in the presence of coarse woodchips were smallest when fertilizer was applied in liquid form, as opposed to incorporated or surface applied dry granules. Carbon dioxide emissions increased by 200% in the presence of woodchips, likely due to increased respiration by soil microbial biomass. This study suggests incorporating coarse woodchips into the soil is a viable strategy for increasing water and nutrient retention in degraded, sandy soils. Future research is needed to examine whether increased water retention by woodchips also increases the availability of water and nutrients to plants.

Technical Abstract: Soil degradation and desertification from agricultural land use is a serious and growing problem worldwide. Bringing degraded soils back into production is crucial to stop the cycle of land degradation, followed by abandonment and a subsequent shift of agricultural pressure to previously uncultivated soils. To return degraded and desertified landscapes to productivity, sandy soils must first be improved to enhance water and nutrient holding capacity. In this study we examine the ability of incorporated coarse woodchips to alter water holding capacity in very sandy, degraded soils in the field, complemented by soil column experiments in the laboratory examining the mechanisms behind changes in water retention. In a second phase of our lab studies, we examined nutrient losses, both soluble and gaseous, from laboratory-scale soil columns under different fertilization application regimes. Coarse woodchips incorporated into the soil increased water holding capacity by 16% in the field and 18% in the laboratory which was attributed to absorption of water by the woodchips, with limited evidence of the occurrence of flow path disruption. Soluble nutrient losses of nitrogen and phosphorus were smallest when fertilizer was applied in liquid form, as opposed to incorporated or surface applied dry granules. Carbon dioxide emissions increased by 200% in the presence of woodchips, likely due to increased respiration by the microbial biomass. This study suggests incorporating coarse wood chips into the soil is a viable strategy for increasing water and nutrient retention in very sandy and degraded soils and can provide a basis for enhancing ecological processes. More work is needed to examine whether increased water retention by woodchips also increases the availability of water and nutrients to plants.