Some agricultural areas in South America, such as the coastal deserts of Peru, the Pampas of Argentina and the semi-arid zone of Brazil, are facing increasingly serious soil salinization problems, threatening crop yields and agricultural sustainability. In recent years, bioremediation technology has attracted widespread attention due to its environmental friendliness and cost-effectiveness. Among them, the combined use of Trichoderma harzianum and seaweed fertilizer has shown significant synergistic effects, which can effectively alleviate salt stress, improve soil microecology and enhance crop salt tolerance.
1. Challenges of salinized soils in South America
Salinized soils in South America are mainly distributed in the following areas:
Coastal deserts of Peru and Chile - dependent on groundwater irrigation, leading to the accumulation of sodium salts (Na⁺).
Pampas of Argentina and Uruguay - drought and improper irrigation exacerbate secondary salinization.
Semi-arid areas in northeastern Brazil - strong evaporation and enriched surface salts.
Traditional improvement methods generally involve applying gypsum or leaching, which are costly and may damage soil structure, while microbial-organic fertilizer combined restoration provides a sustainable alternative.
2. Synergistic mechanism of Trichoderma harzianum and seaweed fertilizer
2.1 Contribution of Trichoderma harzianum to salt resistance
Promote root development: Secrete auxin (IAA) to stimulate root growth and enhance water and nutrient absorption capacity.
Osmotic regulation induction: Activate plants to synthesize osmotic protective substances such as proline and betaine, and reduce cell osmotic potential.
Biological control: Inhibit common soil-borne pathogens such as Fusarium and Rhizoctonia in saline-alkali land, and reduce the risk of diseases under salt stress.
2.2 Improvement effect of seaweed fertilizer
Salt chelation: Alginic acid can bind Na⁺ and reduce the toxicity of free salt to plants.
Improvement of soil structure: Polysaccharides promote the formation of aggregate structure and inhibit the rise of salt with capillary action.
Supply of plant hormones: Natural cytokinins, gibberellins, etc. enhance crop resistance.
2.3 Synergistic effect
Enhanced microbial activity: Seaweed fertilizer provides carbon source for Trichoderma harzianum, prolonging its soil colonization time.
Dual regulation of salt: Seaweed fertilizer chelates Na⁺, and Trichoderma promotes plant salt excretion, forming a "soil-plant" joint desalination path.
3. Application cases in South America
3.1 Desert agriculture in coastal Peru
Problem: High-salt irrigation water causes blockage of drip irrigation system, and traditional acid washing is costly.
Solution: Mix seaweed fertilizer and Trichoderma harzianum for irrigation to reduce dripper salt crystallization and improve soil microbial community.
Effect: Field trials showed that dripper blockage rate decreased by 40% and tomato yield increased by 15% (INIA, 2020).
3.2 Salinized soybean field in Argentina
Method: Apply Trichoderma harzianum and seaweed fertilizer before sowing.
Result: Soil Na⁺ content decreased by 18%, and germination rate increased by 20% (Zapata et al., 2022).
3.3 Brazilian salt-tolerant corn experiment
Method: Foliar spraying of seaweed fertilizer + root irrigation with Trichoderma.
Results: Compared with the application of chemical amendments alone, crop biomass increased by 25%, and soil organic matter increased (Embrapa, 2021).
4. Future research directions
Strain selection: Screening of high-salt-tolerant Trichoderma harzianum strains to adapt to extreme saline-alkali land.
Formula optimization: Developing seaweed fertilizer-Trichoderma composite formulations to improve stability.
Economic evaluation: Comparing the long-term cost-effectiveness of chemical improvement and bioremediation.
5. Conclusion
The combined application of Trichoderma harzianum and seaweed fertilizer provides an eco-friendly and economically feasible improvement strategy for salinized soils in South America. In the future, it is necessary to combine soil microbiome analysis and other precision agricultural technologies to further optimize the solution and promote its large-scale application in arid and semi-arid areas.
If you are interested in Trichoderma harzianum and seaweed extract, welcome to discuss and study with us, Dora team.