Paraquat for Range Seeding in Cismontane California

Abstract

A technique was developed for seeding rangelands which are too steep or too rocky to seed by current methods. Hardinggrass (Phalaris tuberosa L. var. stenoptera (Hack.) Hitchc.) and subclover (Trifolium subterraneum L.) were established by seeding immediately after spraying the resident vegetation with 1,1′-dimethyl-4,4′-bipyridinium ion (paraquat). Tested for seeding in sod were single-disk, double-disk, and hoe-type drill openers. The double disk was best adapted to the clay soils most common in the area. A heavy-duty rangeland drill was modified with custom-made, heavy, double-disk openers and equipped with a spray system which sprays either bands or full coverage. The resulting planter will kill weeds, plant seeds, and spread fertilizer any place where a crawler tractor can pull it. Weed-free bands of 6 and 12 inches were compared with full spray coverage. No hardinggrass was established without some weed control. In only 5 of 16 tests over a 5-year period was full-spray coverage superior to the 6-inch band. The 12-inch band or full spray may be preferable on shallow soils or soils of low water-holding capacity. Spraying helped establish subclover but, unlike with hardinggrass, was not critical. Grazing or mowing during the establishment period improved stands of both hardinggrass and subclover. Prolonged weed control made paraquat superior to cultivation by giving better weed control and a firmer seedbed.