Acta Horticulture, vol.807, pp.365-370, 2009 (Journal Indexed in ESCI)
Green manuring has a key role in organic agriculture, because it enriches the soil organic matter and provides nutrients to soil microorganisms resulting in an increase in microbial activity. This research was carried out in order to determine the effects of summer green manuring and poultry manure application before planting, on organic head lettuce (Lactuca sativa var. capitata cv. Coolguard) production in the greenhouse. The study was realized in 2006 and 2007 in PE covered greenhouse at the Department of Horticulture, Ege University. The tested summer green manure plants were (1) soybean (Gylcine max. L. Merr.), (2) maize (Zea mays) and (3) cowpea (Vigna sinensis L.) and a plot was left as a control (4) without green manuring. Prior to planting, 7.5 t ha certified poultry manure was applied to subplots and a subplot was left as control. The experimental design was split plots with three replicates where the main plots were green manuring and the subplots poultry manuring. The total yield in head lettuce production was between 4123.3 and 7430.5 g m. The highest yield was obtained from the maize parcel that received poultry manure. Nitrate content of the leaves was higher in the plants of green manure plots that also received poultry manure. Organic matter content of the control parcel was 1.5% at the beginning while after the green manuring it was 1.7, 1.57 and 2.25% at incorporation, 15 and 30 days after incorporation, respectively. Total soil nitrogen also increased during the incorporation.