Attributes of lucerne (Medicago sativa L.) for wastewater applications

Abstract

The agronomic attributes of lucerne (Medicago sativa L.) as a wastewater irrigated crop are examined. Aspects including optimal climatic zone, soil type, harvest methods, forage quality and management regimes are explored. Potential for dry matter yield, optimisation of applied nitrogen uptake and exploitation of physiological factors, such as root depth and growth response to spring temperatures, are examined with respect to wastewater application requirements. Current knowledge on nutrient losses beneath lucerne crops is reported. Responses and limitations of lucerne growth in response to hydraulic loading rates, nutrient loading rates and cropping management are discussed. Process water or municipal wastewater land application systems are site specific with respect to seasonal flows and loads. Matching the attributes of early spring growth potential, high nutrient requirements, crop longevity and a root zone potentially measured in meters, may alleviate some common site and application constraints. A particular appreciation of those specific attributes and how they can be exploited by wastewater managers with respect to nutrient uptake and export is presented.