ISHS Acta Horticulturae 619: XXVI International Horticultural Congress: Potatoes, Healthy Food for Humanity: International Developments in Breeding, Production, Protection and Utilization
COMPOST APPLICATION EFFECTS ON WEED POPULATIONS AND CROP YIELD AND QUALITY IN THREE EARLY-MATURING, ORGANICALLY-MANAGED POTATO (SOLANUM TUBEROSUM) CULTIVARS |
| Authors: | M.D. Kleinhenz, J. Cardina |
| Keywords: | nitrogen, deficiency, maturity, yield, quality |
| Abstract:
Nutrient and weed management are leading production-related challenges in organic farming systems. Soil nutrient effects on crop and weed growth and genetic variation in crop nutrient efficiency and canopy variables suggest that variety selection and soil amendment may have key, interactive roles in organic systems. We report here on the first in a series of studies designed to aid in the development of integrated nutrient and weed management strategies for organic vegetable production. This study tests the null hypothesis that compost application under Ohio conditions does not impact weed populations or crop yield and quality in non-irrigated, organically-grown, short-season potato (Solanum tuberosum) cultivars. Land and methods used met local organic certification requirements. In 2000 and 2001, 89-111 m2 subplots of ‘Dark Red Norland’, ‘Red LaSoda’, and ‘Red Viking’ red-skinned cultivars were planted in 267-334 m2 main plots. Half of the subplots were previously amended with composted dairy manure (6.5 Mg ha-1) to deliver approximately 62 kg N ha-1. Potatoes were planted on 5 and 8 June, 2000 and 14 June, 2001. Rows were machine cultivated two-three times annually before canopy closure and hills were re-shaped each year 28 d after planting. Vines were killed by mowing 60-65 d after planting, when the majority of tubers had reached 4-7 cm in diameter. Tubers were field-cured for three weeks, machine harvested with a one-row digger, placed in darkened storage at 9 °C for two weeks, and graded for size and external quality. In 2001, nine plants per subplot were removed at 40 d after planting to assess treatment effects on leaf area and shoot, root, and tuber mass. Weed density and biomass were estimated before harvest. In 2000 and 2001, none of the six yield variables measured were affected by year- or cultivar-x-compost application interactions. On average, compost application increased the yield of U.S. #1 and B-size tubers 13-14%. Total and cull yield and the percent by weight in the U.S.#1 and B-size classes were unaffected by compost application. Weed densities and biomass were very low in both years, and were not influenced by compost treatments or cultivars. In sum, these results suggest that organic amendments may be required for high N-demanding crops in post-transitional organic systems including leguminous rotation crops. They also suggest that the relatively late planting date avoided the period when most annual weeds emerge, leading to low weed populations in all plots. Vine killing in mid-late August limited seed production by the few surviving weeds. | |
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