Ecological Geochemistry of Pineapple Growing Lands in Longhai City

Pineapple growing areas in Chengxi Town, Longhai was selected for an ecological geochemical study. Samples of pineapple flesh, rock, and soil at a same site for various locations were collected to determine the correlations between the land geochemical characteristics and the fruits grown on the same site. It is found that (a) the contents of Hg, N, Se, and U in the rocks were higher than those in the granite found in South China fold system or other places in China; (b) the N, P, K contents in the soil were higher than the national average for surface soil, and the soil was particularly rich in ammonium N, available P and rapid released K, possibly due to the natural weathering and artificial fertilization in the area; (c) the contents of Ca, Mg, and Fe were relatively low by eluviation, but the available Fe was high; (d) the heavy metals came basically from the geological background with little input from pollution; and, (e) in comparison, the local pineapples were richer in P, but poorer in Ca, Fe, Cd and Pb than those grown in Zhanjiang city. The correlations between the land geochemistry and the chemical contents of the pineapple flesh, as well as the element transfer from the rocks and/or soils to the fruits, indicated that the pineapples efficiently absorbed S, P, Cu, B, K and other nutrients, but did not accumulate the pollutants such as Pb, F, As, and Cr, from the ground. Consequently, with the fertile soil, desirable nutrient transfer and minimal concern with heavy metals, Chengxi seemed to be ideal for pineapple plantation.