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Field experiments were carried out in 2018 and 2019 cropping seasons at Landmark University Teaching and Research farm, Omu-Aran Kwara state, Nigeria, to determine the effect of soil applied Zn-fertilizer, Tithonia diversifolia (Ti), Chromolaena odorata (Ch) and poultry manure (PM) on the performance, yield, minerals and vitamins composition of okra fruits. Treatments were combined and tested as follows:—Control (T1), Control + 10 kg ha−1 Zn (T2), 5 t ha−1 Ti + 5 t ha−1 PM (T3), 5 t ha−1 Ch + 5 t ha−1 PM (T4), 5 t ha−1 Ch + 5 t ha−1 Ti (T5), 10 t ha−1 Ti + 0 kg ha−1 Zn (T6), 10 t ha−1 Ti + 10 kg ha−1 Zn (T7), 10 t ha−1 Ch + 0 kg ha−1 Zn (T8), 10 t ha−1 Ch + 10 kg ha−1 Zn (T9), 10 t ha−1 PM + 0 kg ha−1 Zn (T10), and 10 t ha−1 PM + 10 kg ha−1 Zn (T11). The experiment was laid out in a randomized complete block design with four repetitions. Vegetative, yield and quality parameters of okra were taken. Data were subjected to analysis of variance and means were compared using Duncan Multiple Range Test (DMRT) at p ≤ 0.05. Variations were observed on the vegetative parameters, yield, minerals and vitamin composition of okra among the applied amendments. The combined application of green biomass, poultry manure, and Zn-fertilizer improved all the variables tested as compared to when they were applied singly. Application of Zn-fertilizer to some selected plots significantly increased yield, Zn, Mg and vitamins concentration of okra. Application of 5 t ha−1 Ti + 5 t ha−1 PM + 10 kg ha−1 Zn (T3) and 5 t ha−1 Ch + 5 t ha−1 PM + 10 kg ha−1 Zn (T4) significantly improved all the parameters tested but the use of 5 t ha−1 Ti + 5 t ha−1 PM + 10 kg ha−1 Zn (T3) resulted in optimum yield and at the same time increase minerals and vitamin concentration of okra. The results of this study therefore showed that Tithonia diversifolia (Ti) as green biomass contained and released more and quality nutrients than Chromolaena odorata (Ch) when combined with equal rate of Zn fertilizer and poultry manure.

Field experiments were carried out during the 2016 and 2017 cropping seasons at the Teaching and Research Farm, Landmark University, Omu-Aran, Kwara State (latitude 8.9°N and longitude 50°61 E.), Nigeria, to study the effect of some green manures as an alternative to inorganic fertilizer on growth, yield, mineral and proximate composition of radish. Green manure composed of leaves of Vernonia amygdalina and Chromolaena odorata and were applied as follows: 10 tonnes ha−1 vernonia + 0 tonnes ha−1 chromolaena (T1), 7.5 tonnes ha−1 vernonia + 2.5 tonnes ha−1 chromolaena (T2), 5.0 tonnes ha−1 vernonia + 5.0 tonnes ha−1 chromolaena (T3), 2.5 tonnes ha−1 Vernonia + 7.5 tonnes ha−1 chromolaena (T4), 0 tonnes ha−1 vernonia + 10 tonnes ha−1 chromolaena (T5) while in-organic fertilizer (NPK 20:10:10) was applied at 200 kg NPK ha−1 (T6) and there was a control plot (T7). The experiment was laid out in a Randomized Complete Block Design (RCBD) replicated four times. Vegetative, yield and quality parameters of radish were taken. Data collected were subjected to Analysis of Variance (ANOVA) using Statistical Analysis Software (S.A.S), 2000. Treatment means were compared using Duncan Multiple Range Test (DMRT) at 0.05 level of probability. The study showed that application of green manures increased vegetative, yield and yield parameters and were comparable with application of NPK fertilizer while there was a significant increase in the nutritional composition of radish with application of green manures when compared with NPK and control. It can therefore be concluded that application 10 tonnes ha−1 vernonia + 0 tonnes ha−1 chromolaena (T1) as green manure increased vegetative, yield and yield parameters while application 7.5 tonnes ha−1 vernonia + 2.5 tonnes ha−1 chromolaena (T2) improved radish quality.