Alternative Weed Management Systems Control Weeds in Potato (Solanum tuberosum)1

Five weed management systems utilizing combinations of cover crops, herbicides, and cultivation were tested in potato in 1994 and 1995 in central Washington. A standard herbicide treatment of metribuzin applied preemergence (PRE) at 0.4 kg ai/ha (standard herbicide weed management system [[STD]]) was compared with (1) fall-planted winter rye followed by metribuzin at 0.4 kg/ha applied in a band in the potato hill, followed by reservoir tillage (rye cover crop with herbicide-banded and reservoir-tilled weed management system [[RYESTD]]); (2) cultivation with tine-tooth harrow followed by hilling with shovels and rolling cultivators (total-cultivation weed management system [[CULT]]); (3) fall-planted rapeseed followed by reservoir tillage (rapeseed cover crop and reservoir-tilled weed management system [[RPSD]]); and (4) reservoir tillage alone (reservoir-tilled weed management system [[RESTIL]]). In both years, early-season weed density and final weed biomass were lower in the STD, RYESTD, and CULT systems than in RPSD and RESTIL. Total tuber yield and yield of U.S. ##2 or better were greatest in the RYESTD and STD systems in both years. The CULT system reduced early-season weed densities, but tuber yield was reduced 15%% in 1994, and yield of U.S. ##2 or better was reduced 25%% in 1995 compared with the STD system. The RPSD system reduced early-season in-row weed density from 60 to 70%% and final weed biomass from 29 to 40%% compared with a nontreated check, i.e., a no––cover crop, no-cultivation, no-herbicide weed management system, but tuber yield was 27 to 30%% lower than in the STD system. The RYESTD system was an effective alternative weed management strategy that controlled weeds, decreased PRE-applied herbicide inputs 66%%, and maintained tuber yield.Nomenclature: Metribuzin; potato, Solanum tuberosum L.; rapeseed, Brassica napus; rye, Secale cereale L.Additional index words: Banding, cover crops, cultivation, integrated weed management, glyphosate, reservoir tillage, tillage.Abbreviations: BR, between row; CHECK, no––cover crop, no-cultivation, no-herbicide weed management system; CULT, total-cultivation weed management system; IR, in row; PRE, preemergence; RESTIL, reservoir-tilled weed management system; RPSD, rapeseed cover crop and reservoir-tilled weed management system; RYESTD, rye cover crop with herbicide-banded and reservoir-tilled weed management system; STD, standard herbicide weed management system.