Effect of Bat Guano and Biochar on Okra Yield and Some Soil Properties

Abstract

The difficulty in obtaining commercial fertilizers by smallholder farmers in sub-Saharan Africa makes it very important to optimize the use of local organic resources. In VilanKulo, Mozambique, a study was carried out on okra (Abelmoschus esculentus) over two growing seasons. The soil was a haplic, loamy-sand textured Lixisol. As organic amendments, bat guano and biochar were used. Bat guano is a phosphorus (P)-rich and low-carbon (C)/nitrogen (N)-ratio material from natural deposits on a cave floor. Biochar is a C-rich material prepared via an artisanal process using forest residues as a feedstock. Bat guano was applied at two rates (5 and 10 t ha−1) just before sowing. It was also applied at the same rates one month before sowing. Biochar was used at two rates (5 and 10 t ha−1) applied at sowing. Biochar and guano were mixed at the rates of 1 and 4 t ha−1 and 2 and 8 t ha−1, respectively, and applied at sowing. The experiment also used a non-fertilized control. Field trials were arranged in a completely randomized design with three replicates. The treatments that received high rates of guano tended to show significantly higher fruit yields (>10 t ha−1 as the two-year average) in comparison with the control, which showed the lowest average okra fruit yield (6.21 t ha−1). In the guano treatments, the apparent recovery by okra of some important nutrients, such as N, was greater than the amount of the nutrient contained in the guano itself. This result, together with many others related to the tissue nutrient concentration, soil properties and residual fertilizing value in guano plots, indicated a strong mineralization of guano during the growing season. This was probably due to its low C/N ratio and favourable environmental conditions for the mineralization process. The result also suggests some kind of manuring effect, i.e., a fertilizing effect of guano beyond what can be explained by the nutrient supply. The use of biochar increased the total organic C in the soil and cation exchange capacity (CEC) compared with the control but did not affect the variables related to plant performance. Overall, the results showed that farmers can benefit from the use of guano in the short term because it releases nutrients, while with the use of biochar, the benefits can arise in the long term by improving the soil properties.

Effect of Co-application of Different Biochars and Inorganic Fertilizers on the Growth and Yield of Okra (Abelmoschus esculentus L.)

“…And particularly, treatments having the highest level of biochars showed significant improvement over both the T0 (control) and T1 (only chemical fertilizer). Findings of Many other studies also reported significant increase in yield and yield related parameters of okra after application of various biochars at different levels that corroborates to our results (Yakubu, et al, E. 2020;Dimande, et al, 2023;Acharya, et al, 2023). Correlating to yield and yield indexes, soil pH was also positively influenced by biochar treatments.…”

“…Being basic in nature biochar can positively alter soil pH and it has been proved by many study results. Corroborating to previous findings (Smebye et al, 2016 andSi et al, 2018;Sial, et al, 2019;Dimande, et al, 2023), we also observed that both TWB and SSB applied at 5% and 10% caused significant amplification in soil pH. Altered pH might have facilitated nutrient availability in soil and caused better yield of okra in biochar plus fertilizer treatments (Artiola et al 2012).…”

Intercropped Maize and Cowpea Increased the Land Equivalent Ratio and Enhanced Crop Access to More Nitrogen and Phosphorus Compared to Cultivation as Sole Crops

“…In the present study, the short duration of the experiments did not permit significant variations in the determined soil properties. Furthermore, sandy soils and tropical climates lead to rapid degradation of organic residues [62,63], also contributing to a reduced probability of observing significant differences in soil properties between the three treatments.…”

“…One of the main recognized benefits of including legumes in rotations is their contribution of N to the subsequent crops [64,65]. The contribution of cowpea to N supply for cabbage may have increased due to the cultivation in sandy soil and a tropical climate, where the rate of mineralization of organic residues is usually high [62,63]. Therefore, cowpea grown as a sole crop or in intercrop seems to be a good preceding crop for non-legume species, provided there is not too much time between the end of its cropping cycle and the beginning of the succeeding crop to reduce the risks of N loss to the environment.…”

AGRONOMIC PERFORMANCE OF SESAME (Sesamum indicum) UNDER DIFFERENT FERTILIZER MANAGEMENT

“…A similar performance was reported by Tarigan et al (2018), that application of guano fertilizer gave the best growth responses in height and stem diameter of cacao seedlings. Similarly, Dimande et al (2023) also found that okra crops that received high rates of guano fertilizer (10 t ha -1 ) had higher plant height, number of leaves, leaf area, total wet weight, and total dry weight than the control treatment.…”