Profitability and agronomic potential of cotton (Gossypium hirsutum L.) under biochar-compost-based amendments in three agroecological zones of northern Benin

Abstract

Low land productivity is a major constraint facing agriculture in sub-Saharan Africa, which severely affects crop yields, particularly cotton which is main export agricultural produce of Northern Benin. To overcome this situation, the hill-placement of microdose biochar-compost-based amendments was carried out at two research stations and on farmer's fields in three agroecological zones of northern Benin. The study aims to evaluate the agronomic and economic performance of cotton under two types of compost and biochar-based amendments. On stations, the experimental design used was a complete randomized block with one factor and ten treatments replicated four times as follows: (i) absolute control without any amendment (Ck), (ii) mineral fertilizer (MF) at 200 kg/ha, (iii) cow dung-based compost at 200kg/ha (CP1_200) and (iv) 300kg (CP1_300), (v) household waste-based compost at 200kg/ha (CP2_200) and (vi) 300 kg (CP2_300), the combination of CP1 and 15% biochar designated Terra preta (TP) applied at 200kg/ha (vii, TP1_200) and 300kg/ha (viii, TP1_300), the combination of CP2 and 15% biochar applied at 200kg/ha (ix, TP2_200) and 300kg/ha (x, TP2_300). On-farms, the experimental design was a randomized complete block with one factor and six optimal treatments extracted from the on-station experiments with three replicates installed in four farmers' fields from each location studied. The six treatments were: Ck, MF, CP1_200, CP2_200, TP1_200 and TP2_200. Cotton growth (Plant height, number of vegetative and reproductive branches and total bolls per plant) and yield data were collected. The treatment TP1_300 yielded higher cotton seed with 2.53 t/ha, i.e., 86% more than the absolute control. However, the highest plant growth parameters were obtained with MF which were similar to those obtained with TP1_300 (P > 0.05). Likewise, at farms, the highest plant growth parameters and yield were observed with MF followed by TP1_200 (with a cotton seed yield increase of 146% compared to the control, P < 0.05). In addition, no significant differences were observed between organic fertilizers treatments for growth variables. However yield differences occurred. To resume, TP1_300 kg/ha performed best in terms of growth and yield in on-station experiments, while on-farms, TP1_200 kg/ha produced the highest responses of cotton. Value Cost Ratio (VCR) and Benefit Cost Ratio (BCR) values were generally as good or even better for MF treatment and treatments involving CP1 at both on station and on farm, compared to Ck. Although applying mineral fertilizer (MF) alone as currently done by many farmers appears to make economic sense, this practice is unlikely to be sustainable in the long term. Applying TP1_200 and TP1_300 are two possible strategies that are affordable to farmers and provide returns on investment at least as good as the current practice of sole application of MF. However, a long-term study to assess the effect of compost-activated biochar on crop productivity and soil quality is advised.

Evaluation of Cotton Stalk Biochar Use Efficiency on Cotton Yield in Zambia

“…The high pH of biochar is useful in reclamation or increasing uptake of nutrients in acidic soils. Tovihoudji et al 2022 found that biochar had a pH of 10.21, with concentrations of 50.03% C, 0.31% total N, and 13.76% ash. So, Biochar increased the availability of nutrients in soil under acidic soil stress condition than other soil type (Uzma et al, 2015 andKarthik et al, 2020).…”

“…which, led to the improvement of physical, chemical and biological properties of the soil. Also, the bene ts to cotton nutrient content, growth, yields, productivity, and economic bene ts (Tovihoudji et al 2022 andLi et al, 2023). Biochar, "green charcoal", is a result of the slow pyrolysis of plant biomass (straw) in a under hypoxia or anaerobic conditions at 300-1000 ℃, which produces a product with very high carbon content.…”

Research trends on biochar-based smart fertilizers as an option for the sustainable agricultural land management: Bibliometric analysis and review

“…Nigeria and Ghana from West Africa and their collaboration with other countries on the theme is nil. A recent work on the topic was published in Benin on profitability and agronomic potential of cotton under biochar-compost-based amendments which showed high return on investment compared with biochar and mineral fertilizer alone (36). It is necessary to initiate research projects involving collaboration between African countries and other countries, especially, countries that form more bridges in the network.…”

“…Previous studies have synthesized the articles published on biochar-based fertilizers but none of them used the concept of smart fertilizers. Some of them presented the different formulations and methods to produce biochar-based fertilizers and their effect on soil and crops (35)(36)(37)(38). Melo et al (39) reported that biochar-based fertilizers increased crop productivity by 10% over fertilized controls and by 186% over absolute controls.…”