EFFECT OF MANURING ON SOIL PROPERTIES AND NUTRITIONAL QUALITIES ON SELECTED LEAFY VEGETABLES IN SOUTHWESTERN NIGERIA.

Abstract

Field experiment was carried out at the Teaching and Research Farm of the Federal University of Technology, Akure, Ondo State, Nigeria to examine the effect of manuring on the growth and yield of three leafy vegetable species (Amaranthus cruentus, Corchorus olitorius and Celosia argentea). The experimental design used was 3 x 5 factorial scheme laid out in Randomized Complete Block Design (RCBD) replicated three times. The field was laid out in beds of 2 m x 1 m and 0.5 m alley between beds and the total beds were 45. The growth parameters assessed included plant height and number of leaves while the yield parameters were total biomass, marketable yield and edible yield. Proximate analysis was also carried out in the laboratory to determine the nutritional compositions of the harvested leafy vegetables. The results from the study showed that there was no significant difference (P<0.05) in the proximate contents of Amaranthus cruentus plant among different levels of poultry manure and N.P.K used. However, carbohydrate and protein contents were higher in 4 t/ha (63.71%) and NPK (16.56%), respectively. Likewise the proximate contents of Celosia argentea were not significantly different (P>0.005) among the poultry manure and NPK used. Moisture content ranged from 17.23% to 23.26% in Celosia argentea plot treated with 4 t/ha ash and fat content. Highest protein and crude contents were also recorded on Celosia argentea plot treated with NPK. There was also no significant difference (p> 0.005) in proximate contents of Corchorus olitorius due to poultry manure and NPK treatment. Highest proximate contents were recorded with Corchorus olitorius plant treated with 4 t/ha of poultry manure. Amaranthus cruentus had the lowest proximate contents except in carbohydrate (63.71%), while Corchorus olitorius had the highest proximate contents, except in moisture content (23.26%) and carbohydrate (63.70%). Effects of different levels of poultry manure and NPK showed there was no significant difference (p>0.05) in plant height and number of leaves among the levels of manure used. Meanwhile, Amaranthus cruentus plant treated with 4 t/ha of poultry manure had the highest plant weights for the three weeks of observation except in week 1 where NPK was the highest. There was also no significant difference in number of leaves counted. The yield parameters of the vegetables due to different levels of poultry manure showed that edible yield of Amaranthus cruentus treated with 0 t/ha (0.33) was not significantly different (p>0.05) from each other. The highest marketable yield of Amaranthus cruentus was recorded in NPK (2.10) and least in 0 t/ha (0.53). Total biomass of NPK (2.43) was not significantly different (p>0.05) from 4 t/ha (2.12) in edible yields and marketable yield. For Corchorus olitorius’s yield parameter, NPK was not significantly different (p>0.05) from edible yield, marketable yield and total biomass of 4 t/ha.