Cover crops for soil health and forage

Abstract

Cover crops have numerous benefits and while cover crops have been used for centuries, currently there are few producers in Kansas growing them and so there is a need for additional research on how cover crops affect soil properties, and on the potential for utilizing cover crops as forage. Two studies are presented in this thesis. The first study evaluated the use of cover crops in a vegetable production system as compared to a fully tilled control. This study evaluated soil physical properties in the form of wet aggregate stability and infiltration, and microbial properties by soil microbial biomass carbon (MBC). Over the three year study, the most pronounced differences observed were in the wet aggregate stability between the cover crop and control treatments where the cover crop treatments had better soil aggregation compared to the control. At the conclusion of the study, there was not a difference between fall and spring planted cover crop treatments. The second study evaluates species composition and forage quality of various combinations of multi-species cover crop mixtures. This study evaluated sixteen treatments, each consisting of a three-way mixture of a brassica (turnip or radish), grass (rye, wheat, barley, oat), and a legume (berseem clover or Austrian winter pea). Species composition analysis found that the brassica species dominated the mixtures (60-80% by mass on a dry weight basis) in 2014 while the grass species were dominant (62 – 67%) in 2015. Overall all treatments produced prime quality forage (as compared to hay values), however some treatments cost significantly more to plant than others. Therefore an economic analysis compared the treatments and found that the treatments containing turnips and oats generally provided the best return on investment given that both of these species were among the cheapest to plant and produced moderate to high biomass compared to the other treatments. The results of these projects point to the potential benefits that cover crops can have for producers interested in improving soil or utilizing cover crops for forage.