Drought stress negatively affects numerous biochemical reactions and physiological responses in plants involved in nutrient homeostasis, photosynthesis, redox balance, energy production, photorespiration, water balance, and lipid metabolism. To limit the water lost by transpiration, plants close their stomata under drought stress, concomitantly limiting their CO2 uptake and fixation potential. Closed stomata directly affect photosynthesis and increase the production of reactive oxygen species (ROS), which leads to the oxidation of the lipid bilayers in the cell, therefore contributing to senescence and cell death.
The application of a biostimulant to leaves is one strategy employed to minimize the physiological problems arising from environmental stress, thereby increasing yield and enhancing final product quality. Biostimulants are sustainable, environmentally friendly, cost-effective products used to improve agricultural production. The concept of biostimulants has been around since 1933 but has received more attention in recent years as a possible solution to help mitigate the effects of the changing climate on agriculture. According to the European Biostimulants Industry Council (EBIC), plant biostimulants contain substances and/or microorganisms that, when applied to plants or the rhizosphere, stimulate natural processes to benefit nutrient uptake, nutrient efficiency, abiotic stress tolerance, and crop quality. Many substances act as biostimulants, such as seaweed extracts, humic substances, inorganic elements, biopolymers, and amino acids.
Seaweeds are multicellular, macroscopic organisms found in marine ecosystems that are a plentiful source of polysaccharides, polyunsaturated fatty acids, enzymes, and bioactive peptides. The most widely used plant biostimulant is the brown seaweed Ascophyllum nodosum. A. nodosum produces compounds not generated by terrestrial organisms that are thought to be vital for its survival in extremely stressful environments. A. nodosum extract is a natural product that stimulates cytokinin production in plants and may also help maintain turgor pressure in cells and a negative water potential, improve photosynthesis and the contents of photosynthetic pigments, and promote plant growth and defense responses.
The application of biostimulant has emerged as a promising strategy to maximize sugarcane yields and promote crop longevity, specifically by increasing the number of ratoon harvests. Biostimulants can be applied to the soil or leaves, depending on their composition and the desired outcomes. The foliar application of biostimulant during the sugarcane crop cycle minimized the adverse effects of weather on plants, resulting in considerable development and high stalk yields. Yield increases were also recently reported in sugarcane following biostimulant treatment. This phenomenon might be attributed to the activation of various physiological responses in crops by the biostimulant, which enhances nutrient utilization efficiency, stimulates plant development, and enhances nutrient uptake from fertilized soil.
A.nodosum extracts are known for their rich contents of bioactive phenolic compounds such as phlorotannins and unique polysaccharides. The foliar application of nutrients alone or with the biostimulant did not affect the technological quality of sugarcane. Perhaps the high stalk yield resulted in a dilution effect on sucrose content due to increased plant water content. Under drought conditions, plants often suffer from nutrient shortages due to diminished nutrient uptake by the roots and limited mineral mobilization caused by water scarcity. Nutrients are vital to plant biology and are crucial for sustaining growth and development, particularly under abiotic stress conditions. In general, biostimulant treatment enhanced nutrient uptake; maintained nutrient balance within the plant, mitigating the loss of biomass due to stress; and increased nutrient content in aboveground plant tissues, especially under drought conditions. We observed that biostimulant application increased the nutritional resilience of sugarcane plants, especially during unfavorable weather periods (dry season; e.g., winter in Southeast Brazil), with lower nutrient content compared to plants treated with nutrients alone or the control treatment. Conversely, when biostimulant was applied during favorable conditions (spring), nutrient uptake increased compared to other treatments. Therefore, the application of biostimulant to sugarcane during drought periods might help improve plant nutritional status, facilitating consistent growth and development.
The use of A. nodosum extract as a biostimulant in agriculture is promising and presents numerous research opportunities. Several questions remain, such as determining the optimal application rate of A. nodosum extract and the best application method (e.g., drenching or spraying). Additionally, it will be important to establish the ideal timing of application and whether re-application is necessary during the growing season and at what intervals. The answers to these questions may vary among crops and climatic conditions. Finally, biostimulant application promotes better agronomic efficiency than nutrient mixture alone, enhancing plant nutritional resilience during unfavorable periods, such as during the dry season.
Modern agricultural practices have become more sustainable and environmentally friendly. This agronomic approach strives to limit inputs without compromising crop yield and quality over a short timeframe and at a lower cost. The foliar application of a biostimulant is a compelling option for improving the yield of sugarcane and the technological quality of raw materials in a sustainable, environmentally friendly manner.
The foliar application of seaweed extract from A. nodosum combined with nutrients enhanced the resilience of sugarcane plants to adverse environmental conditions, improved nutrient accumulation, and increased stalk yield. Applying biostimulant onto the leaves of sugarcane plants before or after the dry season resulted in a significant increase in stalk production compared to the untreated controls and even to foliar application of nutrients in both cane-plant and ratoon fields. The foliar application of biostimulant, especially during the dry season (fall), resulted in the improved nutritional resilience of sugarcane plants. Furthermore, biostimulant treatment maximized the agronomic efficiency when used in both cane-plant and ratoon fields, regardless of application time (fall or spring) compared to the application of nutrients alone.
Therefore, Dora Agriculture's Algamax is derived from Ascophyllum nodosum. Dora also has seaweed extract from other sources, such as kelp and Ecklonia maxima. If you are interested in seaweed fertilizer, please feel free to contact us.