EFFECT OF BLACK MEDIC (MEDICAGO LUPULINA) AND NITROGEN FERTILISER ON CROP YIELD AND SOIL NITROGEN

摘要

Black medic {Medicago lupulina, cv. George) is a weed, however it can also be used as a self-seeding legume cover crop that may improve farm productivity (Entz et a/., 2007). Black medic is able to produce a persistent seed bank and self-reseed each year over a wide variety of growing conditions. Black medic has relatively slow growth in the spring compared to annual crops and this reduces black medic's competitiveness with annual crops during the early stages of crop development. Black medic has thepotential to increase the nitrogen available to the crop during the growing season; however, once black medic is established it will be hard to eradicate from production field if it is deemed as undesirable. The objective of this study is to evaluate the benefits and problems of black medic as a self-seeding legume cover crop.