Gordon Rajendram the soil scientist

January 2025

The Role of Organic Mulches in Protecting Soil Health During Summer Droughts – Insights from Dr Gordon Rajendram

The Growing Challenge of Summer DroughtsSummer droughts are a persistent challenge, placing soil health and crop productivity under strain. Dr Gordon Rajendram, an expert in sustainable agriculture, highlights that organic mulches are a key tool for maintaining soil resilience during these periods. Research supports their role in moisture retention, temperature regulation, and preventing soil degradation, making them vital for drought management. How Organic Mulches Protect SoilOrganic mulches, including straw, wood chips, and compost, reduce evaporation by covering the soil surface, retaining water, and providing plants with consistent moisture. Studies show that mulches can decrease water loss by up to 35%, outperforming bare soil (Chalker-Scott, 2007). Mulches also protect soil from extreme temperatures, insulating it and maintaining conditions conducive to root and microbial health, enhancing soil biodiversity and nutrient cycling (Chalker-Scott, 2007; Lalljee, 2020).“Mulching is one of the simplest yet most effective ways to combat drought and improve soil health,” says Dr Rajendram. Preventing Erosion and Enriching SoilDr Rajendram also highlights mulches’ ability to prevent erosion and compaction. By cushioning the soil and reducing surface runoff, mulches preserve soil structure. A study found a 1.5 cm layer of straw reduced soil erosion by 86%, demonstrating the protective capacity of organic mulch (Chalker-Scott, 2007). As these materials decompose, they enrich the soil with organic matter, improving texture and fertility (Chalker-Scott, 2007; Lalljee, 2020). Practical Tips for Applying MulchesThe effectiveness of mulches depends on proper application. Dr Rajendram recommends an even layer of mulch, avoiding direct contact with plant stems to reduce disease risks. For long-term benefits, selecting materials suited to soil types and crops is essential (Chalker-Scott, 2007). ConclusionDr Gordon Rajendram’s research affirms that organic mulches are essential for protecting soil health during summer droughts. By conserving moisture, stabilising temperatures, and improving soil structure, mulches help farmers and gardeners build resilience, ensuring sustainable productivity. References Chalker-Scott, L. (2007). Impact of mulches on landscape plants and the environment: A review. Journal of Environmental Horticulture, 25(4), 239–249. Lalljee, B. (2020). Soil health and climate change: An analysis of soil protection and drought management using organic mulches. Agronomy, 10(4), 605. https://doi.org/10.3390/agronomy10040605 For more information, please contact: Contact Dr Gordon Rajendram 021 466077 rajendram@xtra.co.nz www.gordonrajendramsoilscientist.co.nz Contact MediaPA phillip@mediapa.co.nz 027 458 7724

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Dr Gordon Rajendram: Implementing Agroforestry Practices to Mitigate Soil Temperature Extremes

In New Zealand’s diverse climate, managing soil health is essential for sustainable agriculture. Dr Gordon Rajendram, a leading New Zealand soil scientist, advocates agroforestry as a transformative approach to mitigating soil temperature extremes while improving farm productivity. Integrating trees with crops and pastures helps stabilise soil conditions, buffers against environmental stresses, and enhances overall resilience. Agroforestry systems can reduce soil temperature fluctuations by up to 9% through shade provision and improved microclimates (Riyadh et al., 2024; Sarmiento-Soler et al., 2022). Trees act as “safety nets,” capturing nutrients via deep roots and increasing soil organic matter, which boosts moisture retention and reduces evaporation. This is particularly beneficial for New Zealand’s agricultural regions prone to droughts and frosts, such as Canterbury and Central Otago (Fahad et al., 2022; Surki et al., 2023). In addition to temperature moderation, agroforestry offers numerous ecological and economic benefits. Species like mānuka and kānuka not only fix nitrogen but also enrich soils with organic matter, reducing dependency on synthetic fertilisers. Windbreaks formed by tree rows minimise soil erosion, a persistent issue in Hawke’s Bay and other erosion-prone areas (Fahad et al., 2022; Riyadh et al., 2024). Furthermore, agroforestry fosters biodiversity, provides habitats for native species, and enhances the broader ecosystem (Surki et al., 2023). “Agroforestry is a holistic solution that merges ecological restoration with agricultural productivity,” says Dr Gordon Rajendram. “By adopting these practices, farmers can mitigate soil extremes, reduce reliance on chemical inputs, and build resilience to climate challenges.” Success in agroforestry lies in careful design. Selecting tree species adapted to local conditions, ensuring appropriate planting densities, and managing inter-species competition are critical. Agroforestry has been shown to improve soil health indicators, including organic carbon and nutrient cycling, which are key to sustaining long-term agricultural yields (Fahad et al., 2022; Sarmiento-Soler et al., 2022). Dr Gordon Rajendram’s advocacy underscores the potential of agroforestry to future-proof New Zealand’s farms. By aligning ecological principles with farming innovation, his approach offers a practical roadmap for sustainable agriculture in the face of a changing climate. References For more information, please contact: Contact Dr Gordon Rajendram 021 466077 rajendram@xtra.co.nz www.gordonrajendramsoilscientist.co.nz Contact Media PA phillip@mediapa.co.nz 027 458 7724

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