The Effects of Waterlogging, Sewage Sludge and Manure on the Growth Characteristics of Sunflower in a Sandy Loam Soil

The effects of waterlogging and organic fertilizers on sunflower (Helianthus annuus L.) growth characteristics were investigated in greenhouse conditions. A factorial experiment based on completely randomized design with three replications was conducted including duration of waterlogging at five levels (0, 2, 4, 8, 22 days) and source and amount of organic fertilizer at five levels (0, 15 and 30 grams of both manure and sewage sludge per kg of soil). The results showed that by increasing the duration of waterlogging, leaf chlorophyll index, wet and dry weight of root and shoot as well as shoot/root dry weight ratio were decreased but plant height and stem diameter were increased and leaf area did not change significantly. By application of both organic fertilizers chlorophyll index, leaf area, stem diameter, wet and dry weight of shoot and root, and shoot/root dry weight ratio were increased but plant height did not change significantly. The interactive effect of waterlogging and organic fertilizer on chlorophyll index, leaf area and shoot/root dry weight ratio was significant but on other studied characteristics was not significant. The highest amount of wet weight of shoot and root and leaf area was found in 30 grams of sewage sludge and without waterlogging treatment. The sewage sludge increased sunflower shoot and root growth more than cow manure. The results also showed that the dry matter of sunflower shoot was more sensitive than of roots to waterlogging stress.