Effect of Yadbiovitalizer on yield of Irish Potatoes in Limuru area, Kenya

Abstract

Organic resources play dominant role in soil fertility management in the tropics through their short-term effects on nutrient supply and longer-term contribution to soil organic matter (SOM) formation. Biovitalizer herein referred to as 'YAD' is a locally manufactured organic product and is reported to be a slow release fertilizer. A field experiment was set up to investigate the effects of different applications of manure and fertilizers on the growth and fresh tuber weight of potatoes (Solanum tuberosum) in Limuru area, Kiambu County in Kenya. The treatments consisted of Diammonium phosphate (DAP)fertilizer(l8:46:0) at 500kg/ha, Farmyard manure (FYM) (I tonlha), YAD Bio Vitalizer® (750 kg/ha), Control (no fertilizer or manure applied), DAP (250 kg/ hal + FYM (500 kglha), DAP (250 kg/ha) + YAD (375 kg/ha, FYM (500 kglha) + YAD (375 kglha).Treatments of YAD alone were applied with Ecoh balance fohar feed 2 weeks after emergence and then after every other week. The test variety was Tigoni. The experiment was conducted during the short rains season in 2010 and the long rains season in 2011 and was laid out in randomized complete block design (RCBD) with three replications.Plant spacing was 75 cm between rows and 30 cm between plants .Results showed that there were significant differences in number of tubers during the short rain season of 2010 but not during the long rain season of 2011 at P:S0.05. DAP+ FYM treatment had the highest number of tubers and also the highest tuber weights in both seasons. YAD yielded the highest ware yield (5.7 tons/ha) and the lowest chatt yield( 0.2 tons/ha) during the short rains season of 2010. The experiments need to be repeated on smallholder farmers' fields where the masking effects of the residual fertilizers could be eliminated. In addition, the cost benefit ratio of different fertilizer combinations especially the use of organic fertilizers needs to be evaluated at farmers' fields so as to make the most profitable recommendations to Irish potato producers in Kenya.