Comparative effects of Bioslurry and chemical fertilizer on soil properties and performance of Spider plant (Cleome gynandra L).

Abstract

Spider plant (Cleome gynandra L.) is a promising indigenous leafy vegetable in the diet of many African rural populations. However, soil fertility for production of spider plant remains an unexploited area leading to low crop yields. Bioslurry (BS) is a by-product of biogas production rich in organic matter, plant nutrients and a potential substitute for chemical fertilizer (CF). It can also be utilized as a soil amendment to restore soil health. Pot and field experiments were conducted to compare the effects of BS and CF on soil properties and performance of spider plant. A factorial combination of two landraces of spider plant were laid out in CRD and RCBD with three replications in the greenhouse and field, respectively. Treatments were landraces (Tot 89-26 and Rothwe), and N applied as Urea at 0, 60, 120, and 180kg N/ha and bioslurry at 0, 10, 20 and 30 ton/ha using a sandy loam soil. Results revealed that fertilization with BS and CF significantly (p<0.05) improved plant growth parameters and the effect between the two fertilizers was not statistically different. The highest plant height (27.04cm), leaf number (23.39) and leaf petiole length (9.43cm) were recorded from BS20, CF60 and BS20 respectively compared to the control. Accession alone influenced leaf petiole length and leaf number. All fertilizer treatments significantly increased yield parameters. Furthermore, application rate of 120kg N /ha and 20 ton/ha BS recorded the highest chlorophyll content while high stomatal conductance was recorded from 30 ton/ha BS and the results were at par with BS20, CF60, CF120 and CF180. Spider plant efficiently used N when low rates of bioslurry and urea at 10 ton/ha and 60kg N/ha respectively were applied. Results showed a highly significant (p≤ 0.001) effect of fertilizer application on CO2 emissions and carbon sequestration. High CO2 emissions and low carbon sequestration were recorded from 180kg N/ha of Urea while low emissions and high carbon sequestration were recorded from 30 ton/ha of bioslurry. Various application rates of bioslurry and urea significantly influenced soil xii chemical properties while no significant effect was observed on soil physical properties. Overall, the findings of this study revealed that the impact of bioslurry and urea on growth and yield of spider plant were not significantly different. Thus, bioslurry can be used as an alternate nitrogen supply for spider plant cultivation. Bioslurry significantly improved soil properties, reduced CO2 emissions through carbon sequestration, hence promoting sustainable crop production.