Location: Tropical Crops and Germplasm ResearchTitle: Dry matter production and nutrient content of longan grown on an acid Ultisol Author
Submitted to: Experimental Agriculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/20/2012
Publication Date: 2/22/2013
Citation: Goenaga, R.J. 2013. Dry matter production and nutrient content of longan grown on an acid Ultisol. Experimental Agriculture. 49:225-233. Interpretive Summary: The most productive soils of the world are already under cultivation, and those available for agricultural expansion are often strongly acid, possessing toxic levels of soil aluminum and/or manganese. These elements could drastically reduce crop yields when present in the soil at high concentrations. Incorporation of lime to the soil is a common practice to ameliorate acidity but it is not very effective below the plough layer and often lime is not available to farmers with limited resources. The effect of soil acidity factors on dry matter production and leaf nutrient composition of four longan cultivars was assessed during a 2-year field study. High concentrations of soil aluminum (Al) resulted in a 75% reduction in total dry matter production which is indicative that this crop is highly susceptible to acid soils rich in soil Al. Future efforts should be devoted to the screening of longan germplasm to identify Al-tolerant genotypes which could be used as rootstocks in acid soils.
Technical Abstract: Little is known about the adaptability of longan (Dimocarpus longan) to acidic soils high in aluminum (Al). A 2-year field study was conducted to determine the effects of various levels of soil Al on dry matter production, plant growth, and nutrient content in shoots of four cultivars of longan. Soil Al and cultivars were statistically different for all variables measured in the study. Total leaf, petiole, stem and root dry weights significantly decreased at soil Al concentrations ranging from 5.1 cmol/ kg to 12.1 cmol/ kg but this reduction was of a smaller magnitude in roots than in other organs. Shoot content of N, P, K, Ca, Mg, Fe, Mn and Al declined with increases in soil Al. The result of this study demonstrates that longan is highly susceptible to acid soils.