Sustainable Production of Tomato Using Fish Effluents Improved Plant Growth, Yield Components, and Yield in Northern Senegal

Aquaculture and agriculture integration is essential for maximizing water and land productivity in arid and semi-arid regions. Thus, the increase in global water scarcity and the dual use of water for crop and fish production has the potential to optimize water use, dispose of aquaculture wastes, provide additional nutrients to crops, and reduce inorganic fertilizer usage, thus maximizing farm productivity. This greenhouse study was conducted to determine the effects of fish effluents on the growth, yield parameters, and yield of tomatoes (Solanum lycopersicum L.). The experiment was carried out in a randomized complete block design with six replications. The 13 treatments consisted of three irrigation water types (river water—control, Nile tilapia—Oreochromis niloticus, African sharptooth catfish—Clarias gariepinus), four fertilizers (chicken manure, cow manure, sheep manure; recommended rate of NPK—280 kg ha−1 of 10-10-20), and six mixed treatments with fish effluent and 50% of the applied rate of manure alone. Results showed that irrigation with C. gariepinus effluent increased the stem diameter by 21%, the number of flowers by 88%, the fruit number by 50%, the fruit diameter by 24%, the mean fruit weight by 34%, and total fruit weight of tomato by 96% compared to NPK treatments. These effects were more evident when C. gariepinus was mixed with poultry, cow, and sheep manures, which resulted in significantly greater values than recommended rates of NPK. The higher productivity observed from the combined use of C. gariepinus and manure treatments (133% increase, on average) compared to NPK treatments was related to the continuous supply of nutrients and the increase of yield parameters. Therefore, the combined use of C. gariepinus effluent and manure can be a viable alternative for smallholder farmers, for whom inorganic fertilizers are often neither affordable nor available

The Synergistic Effects of Humic Substances and Biofertilizers on Plant Development and Microbial Activity: A Review

Agroecosystem and ecological cycling loops are open when considering the reutilization of inputs applied in farming areas. Non-renewable resources have been transformed or relocated from the air, water and land into the system and are flowing out as wastes rather than reusable, recyclable resources. This current environmental situation is promoting the development of methods able to optimize nutrient cycling, minimize use of external inputs, and maximize input use efficiency. Some humic products are derived from lignin found in wheat straw and biofertilizers as compost and manure teas can be made using residues. Also, these biostimulants might decrease the necessity of synthetic inputs. This review strives to enhance our understanding of the conjunctive use of humic substances (HS) and biofertilizers. The biostimulant effects of each of these compounds are shown in the literature. Thus, our review question is whether the combined application of HS and biofertilizers can promote synergy between both compounds and potentially more efficacy. The effects promoted by using HS plus biofertilizers on plants and microorganisms are very interconnected, so sometimes these effects can be confounded. For instance, the root elongation promoted by HS might increase hyphal fungi colonization. Therefore, this review as divided in three sections: Responses of plants, fungi and bacteria. The findings indicate that the source and application rate of HS will have a strong impact on whether plant growth and microbial activity significantly improved. The microbial species and plant type also influence the response to HS. The prospects of the conjunctive use of and biofertilizers to stimulate plant development and microbial activity in agricultural systems are theoretically substantial when considering the total number of studies included in this review