Field trials were conducted in 1998 and 1999 to determine the influence of harvest-aids on dry bean desiccation, seed yield, and quality. Light Red Kidney and Great Northern dry beans were pulled from the soil and placed on the soil surface to dry or treated with glufosinate at 440 g ai/ha, with glyphosate at 840 g ae/ha, or with paraquat at 560 g ai/ha at three stages during the maturation process. Dry bean seed weight and seed yield were reduced by all harvest-aid treatments applied when only 5 to 7% of the seedpods were yellow. Herbicides did not affect dry bean seed yield, weight, or germination if treatments were delayed until 77 to 85% of the seedpods had turned yellow. Application of harvest-aids at early stages of the maturation process enhanced desiccation of dry bean plants, pods, and seeds, but reduced yield. Herbicides applied at later stages of the maturation process avoided seed yield reductions, but were not as effective in desiccating plants. Therefore, applying glufosinate, glyphosate, or paraquat to reduce the time from dry bean maturation to harvest may not be beneficial when the crop is grown on the high plains of the United States.

Field experiments were conducted in 1996 and 1997 to evaluate the effect of EPTC (S-ethyl dipropyl carbamothioate) plus ethalfluralin at 2.4 plus 0.83 kg ai ha−1, rotary hoeing, in-row cultivation, rotary hoeing plus in-row cultivation, and dry bean canopy on weed seedling emergence. Cumulative weed emergence in 1996 and 1997 was similar in cropped and noncropped areas. Herbicides were more effective than mechanical cultivation in reducing weed emergence 91% in 1996 and 88% in 1997. Weed emergence was similar in both rotary hoed area and cultivated area in 1996 but weed emergence was 44% lower in rotary hoed plots than in cultivated plots in 1997. The Gompertz equation did not adequately predict weed seedling emergence in the untreated control and with in-row cultivation in 1996. Initial weed seedling emergence was observed at about 120 growing degree-days with 3 to 9% cumulative emergence among treatments. In 1997, the Gompertz equation adequately described weed seedling emergence in plots with or without disturbed soil. Weed emergence was first observed at 80 growing degree-days with 6 to 16% cumulative emergence among treatments. Predicted percent weed emergence closely approximated observed emergence in 1996 and 1997. Rotary hoeing plus in-row cultivation reduced maximum percent emergence rate 37% on an average. The greater maximum percent emergence rate obtained with in-row cultivation suggests that this treatment increased weed seedling emergence in 1997. On average, weed seedling emergence in the untreated check was lower in cropped areas than in noncropped areas, implying a competitive effect by the dry bean crop. Although weed seedling emergence occurred throughout the growing season, more weed seedlings emerged in June and early July than in late July and August.