This study was conducted to determine the effect of NPK (15 : 15 : 15) fertilizer on some growth parameters of Punica granatum seedlings towards establishing the fertilizer amount optimal for the growth of P. granatum. Planting bags containing 23.3 kg of soil were used for planting the seeds of Punica granatum, and the soil was treated with different amounts of NPK 15 : 15 : 15 fertilizer (T1 = 0 g, T2 = 1 g, T3 = 2 g, T4 = 3 g, and T5 = 4 g) and watered daily with borehole water. The experiment was laid out in a completely randomized design with four replicates. Data were taken on the number of leaves (NOL), height of plant (HOP), and area of leaves (AOL) every three weeks for fifteen (15) weeks after planting. Results obtained using the Ochekwu Comparative Treatment Average (OCTA) trend showed that all the parameters under investigation increased significantly with an increase in fertilizer amount compared to the control. The optimum growth was observed to range between T3 and T4 for the number of leaves, height of plant, and area of leaves parameters studied. It was also observed that the increment of fertilizer amounts beyond this optimum point reduced biological yield previously obtained. Hence, for the optimum growth of P. granatum seedlings, NPK (15 : 15 : 15) fertilizer should be applied within the range of T3 and T4 or any other measurement that falls within the concentration range of T3 (0.09 g NPK kg−1 soil) and T4 (0.13 g NPK kg−1 soil) in the Niger Delta of Nigeria.

ABSTRACT:The study aimed at enhancing the remediationof crude oil polluted soil of the Niger Delta using cow dung and hydrogen peroxide in either single or combined forms. 5 kg of soil each was polluted with 200 ml of crude oil representing 4% w/v. Five amendment treatments labelledA-E were done in order of A (polluted soil + 1.2 kg cow dung), B (polluted soil + 1000 ml Hydrogen peroxide), C (polluted soil + 0.6 kg cow dung +500 ml hydrogen peroxide), D (polluted soil without amendment) and E (unpolluted soil without amendment).pH, conductivity, organic carbon, organic matter, phosphate, nitrate, total hydrocarbon content, potassium and microbial population were analyzed before and after remediation. The results showed that addition of cowdung and H2O2 enhanced remediation of the polluted soilespecially in treatment A and C with significant increase (p=0.05) in soil conductivity, pH and nutrients when compared to the un-amended soil. Reduction in the total hydrocarbon content (THC) was in the order of A (79.48%)>C (77.95%) >B (75.75%) >D(46%)with significant increase in hydrocarbon degrading microbes in the amended soil.The amendments have the capacities to enhance remediation of crude oil polluted soil.Also, the combined treatments did not have any advantage over the single treatment options as the use of cowdung single treatment perform best in terms of its remediation potential. Therefore, nutrient enhancement should be considered a critical factor in the remediation of crude oil polluted soil. © JASEM http://dx.doi.org/10.4314/jasem.v20i4.30

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Agricultural crop production systems are constantly evaluated to measure its impact on the crop producer, soil, crops and the environment. Hence this investigation was carried out to examine the place of multicropping practice in the drive for sustainable agricultural production in the high humid rainforest agroecology of southern Nigeria. Multicropping allows crop producer to plant two or more crops at a time on the same piece of arable farmland. This practice offers some benefits to crop producer’s resilience, harvest more crop species, income, community and soil quality improvement due to various dead plants and animals parts, nutrients balance due to planting shallow and deep rooted crops; and environmental biodiversity. Our findings revealed multicropping as a practice which offers hope to crop producer with more crops harvested throughout the cropping season, extra income and rich dietary intake of the community. It provides effective pests and diseases control of crops due to crop mix and canopy formation of crops, ameliorate soil physicochemical properties and biodiverse of the environment and act as carbon sink.

This study was conducted to ascertain the allelopathic relationship between Tithonia diversifolia and some cucurbits C. sativus, C. colocynthis and C. lanatus. Seeds of the cucurbits were treated every 24 hours with 10ml of different concentrations (0% [control], 25%, 50% and 100%) prepared from 2.5g/ml stock solution of aqueous extracts of T. diversifolia. Two experiments (the Petri and micro plot experiments) were conducted concurrently and were both laid out in a completely randomized design with four replicates in the Green house of Centre for Ecological Studies, University of Port Harcout. Data were taken on Radicle length, Plumule length, Number of leaves (NOL), Plant Height (PH), Fresh weight and Dry weight for five weeks after plating / sowing for the test cucurbits. Results showed that, compared to the control, there were no significant (p≤0.05) difference in all the parameters investigated for the three cucurbits studied after treatment with different concentrations of T. diversifolia. Results from the analysis shows that for laboratory (Petri dish) experiment, T. diversifolia inhibited the plumule of C. calocynthis in 25% concentration at 5 days after plating; the radicle and plumule of C. lanatus in 50 and 100% concentrations at 5 and 7 days after plating (WAP). T. diversifolia showed no effect on the radicle and plumule length of C. sativus. For Green house (potted) experiment, it stimulated the growth of C. sativus and C. calocynthis in 50% at 5WAP and stimulated the growth of C. lanatus in 25% at 5WAP. Conclusively, there are possibiliites that T. diversifolia possess allelopathic effect on the growth and development of some cucubits.