ALTERNATIVE CROPS, ROTATIONS, AND MANAGEMENT SYSTEMS FOR THE PALOUSE (COMPOST, WHEAT, WASHINGTON)

Two, three-year field experiments were carried out to investigate the possibility of replacing herbicides and mineral fertilizers in cereal rotations by using leguminous forages or green manures in rotations and biological management practices. Wheat following medic produced equal to double the yields of wheat following continuous cereals which had received N fertilizer. Wheat which followed pulse green manures produced 1.18 to 2.35 times more yield than wheat fertilized with 112 kg N/ha which followed combine harvested pulses. Results from fumigation studies and disease symptoms suggested that use of medic reduced cereal diseases. Low wheat yields occurred if wheat was seeded too soon after soil incorporation of a green manure. Wheat interfered strongly with weeds if grown after medic or green manured pulses, but not if grown in continuous cereal rotations. Wheat after medic had more roots which may have improved its ability to suppress weeds. The results suggest that optimized rotations could largely replace pesticides and fertilizers in winter wheat culture.;Budgets compared a peas + medic-medic-wheat management system (PALS) where pesticides were applied only to peas with a conventional wheat-barley-wheat-peas system which received pesticides and fertilizers every year. PALS had 41% of the operating costs of conventional management and maintained higher profits when wheat prices were below ;Conventional, organic, and bio-dynamic management were compared in field trials. Bio-dynamic differed from organic by using herbal preparations in compost and manure and silica field sprays. Application of manure compost did not replace the effect of rotations, but did increase soil C, respiration, and microbial biomass. Compost treated with bio-dynamic preparations had stronger effects than untreated compost. Bio-dynamic preparations increased root growth, tillers, spikes, and spikelets of winter wheat in 1985. Effects of the preparations on wheat were clear only under optimized rotational conditions.