Effects of organic nitrogen fortifiers onsome growth parameters of greenamaranths (Amaranthus caudatus L.)

Chemical fertilizers for boosting crop production are becoming more expensive and scarce. Green amaranth (Amaranthuscaudatus L.) is a fast growing and highly nutritious crop, but its common use in the diet of Nigerians is constrained by itshigh demand for nitrogen fertilizer. Thus, there is a need to find local fertilizer materials that are readily available to peasantfarmers. A preliminary field study was conducted to evaluate urine and neem (Azadirachta indica L. juss) as alternativesources for mineral fertilizers in fortifying organic fertilizer (OF) made from cow dung and market waste compost, and OFfortified with urea and bone meal [organo-mineral fertilizer (OMF)], for yield and growth of green amaranth. Fifteentreatments, based on the percentages of N supplied, were NPK15-15-15, OMF, OF, urine, neem and ten treatments of 50, 60,70, 80 or 90% OF supplemented with a total of 50, 40, 30, 20 and 10% urine or neem, respectively, to provide a totalapplication rate of 100 kg Nha - 1, with no fertilizer treatment as a control. Planting was done in two successions (main withfertilizer treatments and residual without further application). The fertilizer sources and levels had significant effects onplant height, number of leaves, stem girth, fresh weight and dry weight. The residual effects were also significant for plantheight, number of leaves, total fresh and dry weights. Forty percent N urine amendment of the OF produced the highest totalfresh amaranth biomass (269.3 g plot - 1 main effect and 110.8 g plot - 1 residual effect), which was significantly better thanthe values of (140 and 35.3 g plot - 1, respectively) obtained with respect to OMF during main planting and NPK duringresidual planting. Results of our study reveal that 40% N urine fortification of OF was a viable substitute for syntheticfertilizers in production of amaranth, and that urine and neem cake can be alternatives to mineral fertilizer for cropproduction