Organic vegetable production acreage is expanding in California, but little research-based information is available to guide growers. Several new organic fertilizer materials are available but little data exists on efficient use of these materials. During 1998, the following materials: compost (C), pelleted chicken manure (PCM), fish meal (FM), liquid fish (LF), liquid soybean meal (LSM), feather meal (FTM), and seabird guano (SG) were evaluated. Each material was applied at treatment rates of 0, 60, 120, and 180 kg nitrogen (N)/ha to transplanted, sprinkler irrigated bell peppers. The materials were applied as 30N pre-transplant (PRE) and 30N at 20 days post-transplant (POST) for the 60N treatment; 60N PRE and 30N at 20 days POST and 30N at 40 days POST for the 120N treatment; and 60N PRE, 30N at 20 days POST, 45N at 40 days POST, and 45N at 70 days POST for the 180N treatment. Weekly soil nitrate nitrogen (SSN) over 16 weeks POST and fresh pepper yield was determined for all treatments. Weekly SSN varied from lows of 4 mg·kg-1 in 0N-treated plots to over 80 mg·kg-1 in FTM 180N-treated plots. Highest SSN was observed in FTM-, SG-, LSM-, LF-, and FM-treated plots at 180N and peaks in SSN lagged fertilizer application 3 to 4 weeks. Total pepper yield was not as markedly affected as early yield and size. Highest early yield and largest sizes were observed in FTM 180N-treated plots. Compost treated plots at 180N produced highest economic return per fertilizer dollar.
INFLUENCE OF MINERAL AND ORGANIC NITROGEN FERTILIZERS ON GROWTH AND YIELD OF SOME WHEAT VARIETIES AND SOME SOIL PROPERTIES - NORTH DELTA .
