Use of different organic fertilizers on soil fertility improvement,growth and head yield parameters of cabbage (Brassica oleraceae L)

Field experiment was carried out in Akure in therainforest zone of Nigeria to determine the effect of poultrymanure, wood ash and rice bran on the soil fertilityimprovement, growth and head yield of cabbage (Brassicaoleraceae L) in 2011 and 2012 cropping seasons.Methods The three organic fertilizer treatments wereapplied each at 6 t/ha with a reference treatment NPK15-15-15 applied at 300 kg/ha and a control treatmentarranged in a randomized complete block design with threereplicates.Results The results showed significant increases(P.05) in the growth and head yield parameters ofcabbage crop under the different organic fertilizers comparedto the control treatment. The application of poultrymanure resulted in the highest values of cabbage plantheight, stem girth, leaf number, leaf area, head weight,head length and head girth followed by NPK 15-15-15,wood ash and rice bran, respectively. Cabbage headweight, head girth, head length, plant height, stem girth,leaf number and leaf area increased by 17, 18, 8,17, 19, 10and 16 %, respectively, with application of poultry manurecompared to NPK fertilizer. Also, these parametersincreased by 23, 21, 13 29, 25, 17 and 45 % compared tothe wood ash treatment. The highest values of soil pH, Caand Mg were obtained under wood ash application, whilethe highest values of soil O.M and moderate values of soilP, K, Ca and Mg were obtained under poultry manureapplication. Moderate values of soil pH, K, Ca and low %N were also recorded under rice bran treatment. However,the highest K/Ca, K/Mg and P/Mg ratios of 93.1, 74.1 and572.1, respectively, were obtained under NPK 15-15-15fertilizer application compared to 2:1 K/Ca, 2:1 K/Mg and16:1 P/Mg in rice bran treatment.Conclusion The poultry manure applied at 6 t/ha gave thebest results in improving soil fertility, growth and headyield of cabbage, and this was because of its balancednutrient composition and the least C/N ratio.