Building Resilient Crops: Biostimulants for Abiotic Stresses

Climate change and evolving weather patterns challenge growers worldwide, putting crop productivity and profitability under intense pressure. Temperature extremes, erratic rainfall, salinity in irrigation water, and nutrient management issues can all cut into yields and quality. To remain profitable and environmentally responsible, many growers are turning to biostimulants, especially those derived from the brown seaweed Ascophyllum nodosum, as a strategy for building resilient, abiotic stress-tolerant crops.

1. Understanding Abiotic Stress

Abiotic stresses are non-living pressures that negatively impact plant performance. They range from drought and heat waves to salinity and nutrient deficiencies. When plants experience any of these stresses, normal metabolic processes, such as photosynthesis, respiration, or nutrient uptake, can be severely disrupted, diminishing both yield and quality. Climate volatility has exacerbated these challenges, making growers ever more conscious of the need for proactive, scientifically backed solutions.

1.1 A Growing Concern for Modern Farming

• Drought: Sporadic or insufficient rainfall reduces leaf water content, slows photosynthesis, and often leads to stunted growth.
  
• Heat Stress: Elevated temperatures, particularly during flowering or fruit set, can trigger pollen viability issues and lead to smaller, deformed produce.
  
• Salinity: Sodium and chloride ions hinder the uptake of essential nutrients, weakening plant vigour and productivity.
  
• Nutrient Use Inefficiency: Excess nitrogen or phosphorous fertiliser usage can harm the environment and inflate costs; yet under-fertilisation risks yield penalties if nutrients are not efficiently absorbed.
  

2. Biostimulants: A Modern Tool for Crop Resilience

Biostimulants are naturally derived products that enhance plant growth, yield, and abiotic stress tolerance. Unlike traditional fertilisers, they do not directly supply nutrients but instead modify or activate various physiological and biochemical processes within the plant. This leads to enhanced root development, improved photosynthetic efficiency, better water retention, and a raft of other benefits.

Among the many sources of biostimulants, seaweed extracts, particularly from Ascophyllum nodosum, stand out for their richness of bioactive properties. Each of these compounds can influence the plant’s natural processes and metabolism, thereby helping it cope with stressful growing conditions more effectively.

2.1 Why Ascophyllum nodosum?

• High Concentration of Bioactives: Complex Carbohydrates like alginates, fucoidan, and laminarin support cell wall integrity and act as elicitors for plant responses.
  

3. Key Benefits of Seaweed-Based Biostimulants

3.1 Improved Drought Tolerance

Seaweed extracts have been shown to bolster plant water status by:

• Increasing Relative Water Content (RWC) in leaves
  
• Elevating Osmolyte Production, such as proline, which helps stabilise proteins and membranes
  
• Activating Drought-Responsive Genes, including dehydrins that protect cells from water deficit
  

For instance, foliar application of certain Ascophyllum nodosum extracts in tomato crops reduced visible drought symptoms and accelerated recovery after rewatering, as observed in several controlled and open-field trials.

3.2 Protection Against Heat Stress

High temperatures disrupt pollination and fruit development, particularly in heat-sensitive crops like tomato, pepper, and cereals. Biostimulants derived from Ascophyllum nodosum such as MARTELLO® with PSI® Technology:

• Maintain Photosynthetic Efficiency by preventing the degradation of chlorophyll under heat stress.
  
• Boost Heat Shock Proteins (HSPs), safeguarding key metabolic enzymes.
  
• Preserve Carbohydrate Reserves, crucial for sustained fruit set and seed production.
  

Results in tomato fields exposed to temperatures above 30°C demonstrated greater pollen viability and a higher fruit set when MARTELLO® was used.

3.3 Salinity Stress Alleviation

Saline conditions interfere with water uptake and cause ionic toxicity. Seaweed-based biostimulants such as BLOCSAL® with PSI®475 Precision Technology can:

• Regulate Ion Transport, reducing sodium (Na+) accumulation in leaves.
  
• Enhance Potassium (K+) Content, crucial for stomatal function and enzyme activation.
  
• Stimulate Osmoprotectant Synthesis, improving water retention and cell turgor.
  

Published results highlight up to a 23% yield gain in salinity-stressed tomato plants following application of seaweed extracts, attributed to better K+/Na+ ratios and increased proline accumulation.

3.4 Maximising Nutrient Use Efficiency (NUE)

With fertiliser costs soaring, improving NUE is critical. Ascophyllum nodosum-derived biostimulants such as PSI®362 Precision Technology can:

• Upregulate Nitrogen Transporters, promoting better nitrate uptake and assimilation.
  
• Elevate Key Enzymes, including nitrate reductase and glutamine synthase, thereby ensuring more efficient use of applied nutrients.
  

This allows some growers to reduce nitrogen fertiliser by as much as 25% without compromising yield, an economic and environmental win.

3.5 Reduced Pod Shatter and Improved Harvest

Crops like oilseed rape (OSR), soybean, and other legumes can lose up to 25% of yield through premature pod shattering. Applying biostimulants such as SEALICIT® with PSI®759 Precision Technology:

• Strengthens the Replum and Valve Margins, reducing the likelihood of pods bursting.
  
• Modulates Gene Expression (e.g. IND, SHP) that govern cell separation layers, leading to more uniform seed dispersal.
  

4. Practical Application on the Farm

1. Early-Stage Protection
   Some biostimulants are applied as seed coatings to prime the emerging roots and shoots, building stress resilience from the start. This approach is particularly useful for fast-germinating seeds and crops exposed to harsh conditions immediately after sowing.
   
2. Precision Fertiliser Coating
   Products like PSI®362 can be coated directly onto conventional NPK fertiliser granules, allowing for one-pass application and reducing logistical complexities. This also aligns with 4R Nutrient Stewardship, ensuring the right product is placed at the right rate and timing.
   
3. Foliar Sprays
   Growers often opt for foliar sprays just before or during stress periods, such as flowering under high temperatures or when salinity issues intensify mid-season. Proper spray timing can make the difference between losing and retaining the bulk of the harvest.
   
4. Integration into IPM (Integrated Pest Management)
   Biostimulants can often be tank-mixed with other agricultural inputs (like fungicides, insecticides, or fertilisers) to create a holistic crop management system.
   

5. Real-World Success Stories

• Tomato Drought Trials: Applications of MARTELLO® consistently showed higher plant height, lower membrane damage, and at least 8% more marketable fruit after a drought period.
  
• Barley and Wheat NUE: By boosting nitrate transporter gene expression, barley fields treated with precision-engineered Ascophyllum nodosum extract, PSI®362 maintained yields on 25% reduced nitrogen fertiliser.
  
• Oilseed Rape Pod Shatter: Field tests showed a 4.5% average increase in seed yield after a single pre-flowering foliar spray of SEALICIT® primarily by delaying or reducing pod shatter.
  

A growing body of data underscores the diverse capabilities of seaweed-based biostimulants to help farmers adapt to today’s most pressing agronomic constraints. By activating and enhancing natural plant pathways, biostimulants by Brandon Bioscience not only safeguard yields but also provide a stepping stone towards more sustainable farming practices, where resource efficiency and resilience go hand in hand.