Potato Tuber Yield, Tuber Size Distribution, and Quality, As Impacted by Preceding Green Manure Cover Crops Under Irrigated Conditions.

There is the need to develop sustainable systems with higher yields and crop quality. Studies were conducted with green manure cover crops grown under limited irrigation (< 200 mm) to assess the effects of certain types of green manure cover crops on potato tuber yield and quality. On a commercial farm operation prior to the 2006 and 2007 potato season, mustard (Brassica spp.), canola (Brassica napus), and two varieties of sorghum-sudan (Sorghum sudanensis) were planted.  A wet fallow ground treatment where no green manure cover crop was planted, was used as a control. Prior to the 2008 season, barley (Hordeum vulgare L), barley plus applied compost, sunflower (Helianthus annus), peas (Pisum sativum), and annual rye grass (Lolium spp.) cover crops were added. The results of these 2005-2008 studies show that cover crops have the potential to contribute to sustainable food production while increasing potato tuber yields and quality, as measured by tuber size (larger tubers) and appearance (e.g., tubers with reduced defects such as cracks, knobs, and misshapes). In two of the three years, most of the cover crops, especially sorghum sudan, increased yields and/or tuber quality. Positive results from sorghum sudan suggest there is the potential to harvest hay from cover crops and still obtain tuber benefits.