DYNAMICS OF ORGANIC MATER, P AND K IN SOILS OF THE AGROFORESTRY SYSTEMS ‘SPANISH CEDAR-BANANA’ IN TABASCO, MÉXICO

Abstract

In this research we evaluated the dynamics of organic matter (OM), phosphorus (P) and potasium (K) in soils of five agroforestry systems of the spanish cedar-banana complex at the banana region at Teapa, Tabasco, México. Spanish cedar-datil banana (SCDBS), spanish cedar-small giant banana (SCSGBS), spanish cedar (SCS), datil banana (DBS) and grass (GS) systems were the selected systems. Thriplicate soils samples were taken to measure OM, P and K content in soils at three seasons: ´nortes´, dry and rainy, in 2001. Soil samples were taken from two depths: 0 to 30 cm and 30 to 60 cm in each plot. Total volume of the spanish cedar and dry matter production of banana were measured. SCBDS and GS had a low fertility fluvisol eutyric soil. SCSGBS and SCS had a high fertility fluvisol calcaric soil, while DBS had a low fertility fluvisol calcaric. SCSGBS and SCS had the highet content of OM, P and K resulting from higher soil fertility and from nutrient input due to mineralization of fallen leaves from the spanish cedar and banana plants. Dead foliage can reach up to 12 t ha^-1 per year. This system had the highest volume of spanish cedar and the highest yield of banana dry matter. Thus, the agroforestry system spanish cedar-banana is a productive option. DBS system requires to raise the adition of P to soil, since a deficiency was detected. Effects of climate on OM, P and K were not significant. OM, P and K contents were higher at 0-30 cm, and dropped significantly to low and deficient at 30-60 cm depth; nevertheless, these contens can be used by the roots of spanish cedar.