Mr. Fan, who manages a 5-acre durian orchard in Kulim, Kedah, stated that achieving high-quality fruit requires proper fertilization management at different growth stages.

Entering the Production Season
             When interviewed, his first batch of flowers had nearly finished yielding, but like most farmers, the yield was low due to continuous rain during the initial flowering period, which caused the flowers to be knocked off by rain. Currently, Mr. Fan is in the second flowering phase, having already harvested about 50 fruits, which is a satisfactory result. The variety of durians he is harvesting primarily includes Black Thorn; he also has two Musang King trees, with over 70 fruits on the trees, and another tree with 101 fruits. Additionally, some trees are showing flower buds, and it’s expected that the third batch of flowers will yield more fruits.
               In early June 2024, the local durian production season began, and it’s estimated that the season will last until July. If the third batch of flowers successfully bear fruit, the production season may be extended further. In fact, he currently estimates that there are about 880 fruits still on the trees, while there are only 20 fruit-bearing trees in the orchard. It is surprising that each fruit-bearing tree is yielding dozens or even over a hundred fruits, which impressed him greatly. He even mentioned that this high yield is due to proactive thinning operations, which allowed for such productivity, making his diligent orchard management commendable.

Scientific Fertilization Management
               Besides standard orchard operations, Mr. Fan adheres to strict standards for the fertilizers used, which must be certified by laboratory tests to ensure they contain adequate nutrients before application. He believes that scientifically managed fertilization is worth recommending. Over the years of practice, he has developed his own fertilization schedule, ensuring that the process is managed smoothly.
              He mentioned that during the seedling stage, he applied fertilizers containing 15-15-6-4, 15-15-15, and 16-16-16 to promote the growth of durian seedlings. Generally, durian seedlings require balanced nutrients, mainly phosphorus, nitrogen, and potassium, to promote the growth of the root system and leaves, laying a solid foundation for future growth. Additionally, during the seedling stage, Mr. Fan began increasing the application of organic fertilizers. Excessive chemical fertilizers can cause soil compaction, hindering nutrient absorption. Therefore, during the seedling stage, the application of organic fertilizers must match the amount of chemical fertilizers.
              For mature trees, organic fertilizers should be applied more to ensure that the soil has sufficient organic matter, making it easier for the trees to absorb nutrients.
Of course, fertilization management for mature trees is more demanding, especially during the flowering and fruiting stages, where nutrient requirements vary. Mr Fan gave an example: before entering the flowering stage, the trees need to be prepared, so he increases the application of phosphorus fertilizers and applies them to the leaves to enhance flower bud differentiation.
In fact, more phosphorus does not alter the durian tree’s growth process; it only provides the necessary elements for the tree’s growth. The tree’s nutrient status affects the quality of flowering. Adequately nourished trees produce larger and more numerous flowers compared to nutrient-deficient trees. Therefore, actively supplementing phosphorus naturally increases the likelihood of the durian tree flowering.
            Within the appropriate dosage range, nitrogen can have the same effect. However, nitrogen is never promoted as a nutrient for enhancing the reproductive growth of durian trees, as excessive nitrogen can delay reproductive growth, thus postponing the flowering period, which requires precise control. These Black Thorn tree is in its second fruiting phase, currently bearing over 130 fruits, a satisfactory yield. Some trees are showing flower buds, and it’s expected that the third batch of flowers will yield more fruits.

Emphasizing Potassium and Phosphorus During Flowering and Fruiting Stages
               As the durian trees enter the flowering stage, they start to bloom. This stage includes the initiation of flowering and full bloom. At this time, Mr. Fan applies ample amounts of potassium and phosphorus, along with some micronutrients. Based on Mr. Fan’s experience, he has found that potassium and phosphorus are crucial for the formation of floral organs and for pollination. Additionally, sufficient potassium ensures that the flowering and fruiting processes of the durian trees proceed normally, while sufficient potassium and boron effectively strengthen the cell walls of the fruit. A deficiency in calcium and boron usually leads to poor cell wall development, severely affecting cell division and making the fruit prone to cracking, which lowers the quality.
             In light of this, Mr. Fan emphasizes the importance of calcium and boron not only during the fruiting period but also during the flowering stage, ensuring that the plants receive adequate amounts of these nutrients. During the fruiting period, Mr. Fan continues to provide sufficient calcium and boron and increases the amount of potassium fertilizer, supplemented with boron. Generally, his method is to apply these nutrients when the fruit is about the size of an egg, using granular fertilizer. However, Mr. Fan mentioned that if economic conditions allow, foliar fertilizers can also be applied simultaneously to quickly replenish the nutrients needed by the durian trees.
               Regarding foliar fertilizers, besides the high potassium content, Mr. Fan also focuses on the application of amino acids. He noted that amino acid fertilizers are effective in promoting plant growth, enhancing resistance to stress, improving soil conditions, and increasing yield. Additionally, adequate organic fertilizer is also essential. Mr. Fan pointed out that at the appropriate time, he applies organic fertilizer and potassium sulfate to improve fruit quality and prevent the plants from shedding leaves before they have time to recover after harvest.
         In fact, Mr. Fan frequently encountered leaf shedding issues in the past, especially those caused by leaf diseases. Fortunately, by increasing the application of nitrogen in his fertilization practices, the leaves became thicker and more resistant to leaf diseases, while simultaneously addressing the issue of leaf diseases. He mentioned that for several months now, he has not seen any severe outbreaks of leaf diseases, clearly indicating that targeted improvements in fertilization practices can yield tangible results.

Ensuring the Trees Absorb Adequate Nutrients
              In addition to keeping the ground clean, Mr. Fan also cleans the tree trunks to prevent parasitic plants like moss from competing with the durian trees for nutrients. During the fruiting period, Mr. Fan not only continues to supply sufficient potassium and phosphorus but also increases the application of potassium fertilizer, supplemented with boron. At the appropriate time, Mr. Fan applies organic fertilizer and potassium sulfate to improve fruit quality and prevent the trees from shedding leaves before they can recover after the harvest.

Actively Applying for myGap Certification
             Mr. Fan adopts a self-sufficient model for managing his durian orchard, where he manages the orchard, and his children handle the sales through online platforms. This approach has received rave reviews and has encouraged many repeat customers to purchase durians from them. However, Mr. Fan admits that demand far exceeds supply, so he kindly asks his loyal customers to be patient for the next production season.
           Currently, the orchard price for Mr. Fan’s Black Thorn durians has reached RM 80 per kilogram, and last year, he harvested a Black Thorn weighing 3.5 kilograms. Such achievements make him very satisfied with his durian cultivation efforts.
Moreover, he is actively applying for myGap certification to further develop the orchard and meet the requirements for future exports. However, he pointed out that the myGap certification process, though seemingly simple, is quite complicated, involving inspections of water sources and even the slope gradient. He further explained that regulations stipulate that the slope of the orchard must not exceed 30 degrees, as there is a risk of landslides that could cause significant damage, and exceeding this limit would result in a failed certification.
           Regardless, Mr. Fan believes that many small durian orchard owners in the country should actively apply for myGap certification if conditions permit. After all, it is crucial for long-term success, especially since myGap certification can sustain the growth of Malaysia’s durian industry.