Optimization Of Fertilizer Application Rates For Onion, Tomato And Amaranth In Morogoro Municipal, Tanzania

ABSTRACT

Most small scale farmers in Morogoro apply inorganic fertilizers to vegetable crops they grow. However no standard fertilizer application recommendations exist. This may lead to under supply or over supply of nutrients, resulting into economic loss and environmental hazard. Experiments were conducted to establish and recommend the best optimum NPK fertilizer application levels for tomato, onion and amaranth crops in Morogoro Municipal agro - ecological conditions. The experiments were carried out at the Crop Museum of the Sokoine University of Agriculture between December 2016 and May 2017. Single carrier fertilizers of different ratios were used. These fertilizers were Urea, Tripple Super Phosphate and Muriet of Potassh were laid out in randomized complete block design (RCBD) replicated three times. The varieties Assilla, Red Bombay, Lishe for tomato,onion and amaranth respectively and fertilizer levels were assigned to the plots. The fertilizer levels for tomato were; 0, 45, 90,180 kg N ha-1 ; 0, 70,140 kg P ha-1, ; 0, 75,150 kg K ha-1. onion ; 0, 25, 50,100 kg N ha-1, ; 0, 25, 50 kg P ha-1, ; 0, 25, 50 kg K ha-1 and amaranth ; 0, 85,170, 200 kg N ha-1, ; 0, 30, 60 kg P ha-1, ; 0, 30, 60 kg K ha-1. Data were collected on vegetative growth, yield and quality parameters. The data were subjected to analysis of variance using GENSTAT 14th Edition at significance level of 5 %. The results show relative increase with respect to control hence revealed that nitrogen, phosphorus and potassium of 45:140:150 NPK kg ha-1, 50:50:25 NPK kg ha-1 and 200:60:30 NPK kg ha-1 for tomato, onion and amaranth respectively produced higher growth, yield and quality than control. Those rates are recommended to be applied while considering other agronomic practices. However, field study to confirm the findings of this study for those fertilizers to those vegetable crops in this soil type and others with similar characteristics in Morogoro, could particularly be the viable option before it’s recommended to farmers.