FURROW DIKING EFFECTS ON YIELD OF DRYLAND GRAIN-SORGHUM AND WINTER-WHEAT

Dryland sorghum [Sorghum bicolor (L) Moench] and wheat (Triticum aesti vum L.) production in areas where a large fraction of the annual rainf all is received during the fallow period may be improved by rain-conse rving practices. Furrow diking mainly during the growing season has be en shown to improve crop production by conserving rainfall in many par ts of the Southern Great Plains. The objectives of this study were to determine whether seasonal or year-round furrow diking increases dryla nd yields of sorghum and wheat, to test the yield advantage of plantin g sorghum and wheat on a flat seedbed or on beds, and to analyze the d ependence of yield on rainfall. The treatments included nonbedded (FLA T), bedded-nondiked (BND), bed ded-diked during the growing season (BD G), bedded-diked during the fallow period (BDF), and bedded-diked duri ng the fallow period and the growing season (BDFG). Relative to BND, t he BDFG treatment increased yield by up to 72% in sorghum and 23% in w heat. The BDF treatment increased yield by up to 62% in sorghum and 23 % in wheat. Furrow diking during the growing season alone did not sign ificantly increase yield in sorghum or wheat. When annual rainfall exc eeded the average, the FLAT treatment in sorghum yielded less than the BND treatment by 39%. Planting wheat on beds was not an improvement o ver the conventional flat seedbed. Dryland sorghum and wheat productio n in areas where a significant fraction of the annual rainfall is rece ived during the fallow period may be improved by fallow period or year -round furrow diking.