Effect of Different Water Regimes, Planting Dates and Allelopathic on Rice Weeds .

Abstract

Six experiments were initiated at 2002 and 2003 growing seasons at Agriculture Research Center (ARC), in El-Serw station, Giza, Egypt, to develop and integrated control system to weeds in rice fields. Results could be summarized as follow:At 30 days after planting with 100 % field capacity, E. crus-galli emergence (%) reached the maximum values of 90 and 84 %, respectively..The field capacity of 200 % decreased the emergence of E. crus-galli .but, C. difformis reached its maximum under the soil condition of 150 % followed by 200 %. While, the soil condition of 100 % and 50% were not proper for the emergence of C. difformis. whereas, E. geniculata was significantly increased with increasing time of observation after planting up to 60 days under 150 and 200 % field capacity condition.Emergence of E. crus-galli being higher in a short period between 15 to 20 days after planting in both seasons, while maximum emerged seedling of E. crus-galli were recorded at the planting date on first of May and reduced significantly when the planting time was delayed. Consequently, emergence of E. geniculata seedlings increased with delaying the planting date from mid of April to first of June. Early planting date of rice is an important integral part in suppressing E. geniculata. Also, maximum emergence of C. difformis for each planting date was occurred at 50 days with little change between the rates of emergence after 50 or 60 days in each planting date and maximum emergence of C. difformis were occurred when planting date was delayed to 1 st June.E. geniculata has allelopathic effects on the association weed of C. difformisw with increasing the number of emergence of E. geniculata, the performance of C. difformis was reduced.,and increasing the number of E. geniculata at 20 plants/ pot, the competetion effects were significantly increased