Field research from 1986 to 1988 evaluated control of alfalfa, dandelion, orchardgrass, and annual weeds in corn with sequential herbicide treatments. Glyphosate applied the previous fall controlled 95% or more of the dandelion and orchardgrass before postemergence treatments. Atrazine applied early preplant or with paraquat the day before planting only partially controlled the perennial species. Atrazine applied postemergence usually controlled vegetation escaping initial treatment except orchardgrass following the atrazine treatments. Adding tridiphane increased weed control with atrazine or cyanazine applied postemergence only when fall panicum was present. Herbicides applied postemergence increased corn yield compared to the initial treatments alone, and few differences among postemergence treatments were observed. Sequential treatments which included glyphosate applied in the fall controlled 82% or more of each perennial species before the next growing season. Orchardgrass control was 81% or less the following spring when the initial treatment was atrazine or atrazine plus paraquat.

Birdsfoot trefoil (Lotus corniculatus L.) was direct-seeded into five different grass sods after treatment with dalapon (2,2-dichloropropionic acid), glyphosate [N-(phosphonomethyl)glycine], or paraquat (1,1′-dimethyl-4,4′-bipyridinium ion) at varying rates for vegetation control. During establishment, the stands of birdsfoot trefoil were acceptable in all treated- and untreated-sod grass sods except 1 yr in untreated tall fescue (Festuca arundinacea Schreb.) and timothy (Phleum pratensis L.) and 1 yr in tall fescue receiving 3 kg/ha of dalapon. Herbicide treatments resulted in a more rapid development of a significant legume component in the sward and an increase in forage yield over the untreated plots. Minimum herbicide application rates for best return for grass sod control were 0.5, 1, and 5 kg/ha respectively for paraquat, glyphosate, and dalapon.

Rapid germination and root growth have been identified as important plant characteristics for establishment in arid environments. This study evaluates germination, radicle elongation, and root growth rates of two annual grasses, two forage species, and yellow starthistle. Yellow starthistle germination, radicle elongation, and root growth were faster than those of medusahead and hedgehog dogtailgrass. Subterranean clover possessed rapid seedling growth characteristics similar to those of yellow starthistle, whereas Palestine orchardgrass was most delayed.

Hereford cows and their spring-born calves grazed an irrigated grass pasture containing about 13% dandelion based on dry weight yield. Grazing treatments were 1) no grazing, 2) 4 days of grazing just before clipping, and 3) long-term grazing just before clipping. In clippings taken in June and July after the grazing treatments, the percentage dandelion in the forage was similar in all three grazing treatments, indicating that cattle used dandelion as readily as grass. The protein and mineral contents of dandelion were at appropriate levels to meet the established requirements of beef cattle.

The effects of alternating temperatures on seed dormancy changes, germination and seedling emergence were investigated in ‘Arctic’ and ‘Lineta’ orchardgrass (Dactylis glomerata L.). Thermal time models were successfully developed for 0, 5, 10 and 15°C temperature amplitudes, using 28 constant and alternating temperature regimes. These models were then modified by linking seed germination in Petri dishes and seedling emergence in soil. A field experiment was conducted with four seeding dates over 2 years to validate the modified thermal time models. Temperature regimes with a 5–15°C amplitude enhanced seed germination percentages of orchardgrass, indicating that the conditional dormancy was released by these temperature regimes. Base temperatures decreased with increasing temperature amplitude. Seeds germinated more rapidly under alternating temperatures than under constant temperatures. The dual effects of temperature for dormancy breaking and germination were accounted for by thermal time models based on alternating temperature regimes, which accurately predicted the timing and percentage of ‘Arctic’ and ‘Lineta’ orchardgrass seedlings emerging in the field (R2≥0.88).