Influence of rates of alfalfa pellets on water retention and cation exchange capacity of a sandy and a clay soil

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Disturbed and degraded lands often have one physical or chemical limitation to productivity that must be overcome if they are to be restored to pre-disturbance conditions. Their ability to hold onto nutrients as indicated by their cation exchange capacity (CEC) and their ability to hold onto water to ensure a continuous supply to the crop is often limited. One way to overcome these limitations is through the addition of soil amendments especially those of organic origin such as animal manures and crop residue. In several of the areas where these disturbed lands exist, manure is not available and other organic amendments must be sourced to restore the land. Alfalfa pellet is made from dehydrated alfalfa by Western Alfalfa Milling Company Ltd. (WAMCO), a North America's leader in alfalfa pellet production for feed. Alfalfa pellet is a multi-purpose material that can provide vital nutrients and organic matter, possesses water retention properties and can help alleviate soil compaction and aeration issues. CEC is an important soil property that influences plant nutrient storage and uptake. Several studies have shown increases in CEC following animal manure application. To our knowledge, no previous study has examined the effect of alfalfa pellets and rates on soil CEC. One important physical property of soil that greatly affects productivity is water retention. The plant available water capacity of a soil can be estimated from soil water retention at field capacity (FC) and at permanent wilting point (PWP). Soil water retention is largely influenced by increases in soil organic matter. Manure has been known to improve soil water retention. If alfalfa pellets are to serve as an alternative organic amendment for land reclamation, they must have a demonstrated influence on the water retention and cation exchange capacity of the soil. Therefore the objectives of this study are to determine the effect of different rates of alfalfa pellets on the CEC and water retention capacity of a sandy soil and a clay soil. Knowledge of the effect of alfalfa pellets on these soil properties will provide valuable information for WAMCO on the potential of these pellets to serve as an organic amendment thereby increasing their range of use and market potential.