Nutrient Management in Mango
Anunciado, Ismael S., Angeles, Domingo E., Reveche, Ricardo Amiel V., and Mary O. Cedo. Nutrient management in mango (fertilizer application in mango through the diagnostic and recommendation integrated system). Department of Horticulture, College of Agriculture. University of the Philippines Los Baños.
Why Improve Nutrient Management in Mango?
Fertilizer recommendations for mango has been one of the concerns of mango experts, technologists, and growers. Local fertilizer recommendations have been formulated, although some give standards regardless of the wide variations of the agroecological conditions under which the trees are grown.
This project attempted to develop an approach in assessing the fertilizer nutrient requirements of mango based on available techniques and test this approach in at least two locations. One of its objectives was to determine flowering response, yield, and fruit quality of mango as influenced by leaf N, P, K, Ca and Mg levels. Specifically, it aimed to determine the effects of soil-test based compounded fertilizer treatments on leaf N, P, K, Ca and Mg levels, flowering intensity, yield and fruit quality of mango. Furthermore, the project wanted to correlate leaf N, P, K, Ca, and Mg levels prior to flower induction with flowering intensity, yield, and fruit quality and compare the results with the critical levels established elsewhere. Lastly, it aimed to showcase that application of appropriate nutrients is an effective cultural management practice to increase yield and quality of mango.
How was the Project Done?
Two sets of mango trees were fertilized with compounded N-P2O5-K2O fertilizer, one at the mango orchard of Benguet Management Corporation (BMC), located at Iba, Zambales and the other at the plantation of Menzi Farmers Cooperatives (MEFCO), Mati, Davao Oriental. The trees at BMC site are about 15 years old while those at MEFCO orchard are 30-40 years old.
Leaf samples from each experimental tree were gathered prior to flower induction, as well as data on flowering intensity, fruitlet count, fruit retention, and yield. Regression analysis was done to analyze data.
Leaf N, P, K and yield. The results of the regression analysis showed that the levels of leaf N, P, and K significantly influenced the number of fruits harvested per tree. However, their effects on fruit weight were insignificant. The influence of N, P, and K on the number of fruits harvested per tree can be attributed to the combined effect of the three nutrients because not one of the three nutrients had significant interaction effect on number of fruits. Negative interaction was noted between leaf N and K levels. A total of 52% of the variables affecting the number of harvested fruits is due to leaf N, P, and K levels. On the other hand, leaf N, P, and K levels formed only 38% of the factors affecting fruit weight.
Leaf N, P, and K levels, flowering intensity, fruitlet count, and fruit retention. The levels of leaf N, P, and K had no significant influence on fruitlet count and fruit retention. However, they exerted a significant influence on flowering intensity with an R2 value of 0.51. A significant positive interaction existed between leaf P levels and flowering intensity. This shows that the level of P had greater effects on flowering than any of leaf N and K levels. This finding needs further study.
Leaf N, P, K and yield. The yield of mango trees, in kg per tree, was significantly influenced by the levels of leaf N, P, and K. This is in contrast with the results of the BMC site. However, the leaf N, P and K levels accounted only 30% of the factors affecting fruit weight. A high significant interaction existed between leaf P levels and leaf K concentrations.
The number of fruits harvested per tree from the MEFCO site was not influenced by the leaf N, P, and K levels. Again, the result is in contrast with the findings at BMC. Also, the leaf N, P, and K levels of mango trees at MEFCO formed only 20% of the factors affecting the number of harvested fruits.
Leaf N,P, K levels, flowering intensity, fruitlet count, and fruit retention. Although the levels of leaf N, P, and K of mango trees at MEFCO had a highly significant influence on flowering intensity, these effects can be masked by the other factors that affect flowering intensity. This is logical because their combined effects accounted only 17% of the factors affecting flowering intensity of mango.
The levels of leaf N, P, and K had no effect on fruitlet count and fruit retention per panicle. This supports the findings at BMC site.
Although the importance of N, P, and K on yield of mango (fruit weight and fruit number at MEFCO and BMC sites, respectively) has been demonstrated, the results are deemed inadequate for the formulation of a better approach for nutrient management mango orchards. This is so because the generated data are only limited to one crop year. The failure to have at least two cropping years is attributed to two factors. The first is the uncooperative environment that occurred during the project life and the second is the change on project leadership.
The approach adopted by the project in the formulation of interim fertilizer recommendations for MEFCO and BMC sites was on soil test and tissue analysis coupled with the reported nutrient removal of mango. This approach is still logical knowing fully that the soil types of mango orchards nationwide vary widely.
For details of the study, please contact:
Dr. Ma. Lourdes O. Cedo
Department of Horticulture
College of Agriculture
U.P. Los Baños, College, Laguna
Tel. No. (049) 536-2448, 2478
Dr. Domingo E. Angeles
Department of Horticulture
College of Agriculture
U.P. Los Baños, College, LagunaTel. No. (049) 536-2448, 2478