CRUSTING OF RIVER ESTATE SOIL, TRINIDAD, AND ITS EFFECT ON GASEOUS DIFFUSION, PERCOLATION, AND SEEDLING EMERGENCE

Abstract

SummaryThe River Estate Loam in Trinidad is micaceous. It is weakly structured and prone to surface crusting which results in decreased gaseous diffusion, infiltration‐ percolation, and seedling emergence. Mulching with ‘Encap’ (a liquid petroleum product) increased infiltration but not seedling emergence whereas ‘Krilium’ (sodium polyacrilonitrile) was more effective in improving seedling emergence. Bagasse mulch had a beneficial effect on infiltration but in common with pen manure was not very effective in aiding seedling emergence. Thin section examination showed that the uncrusted soil had an open structure with a large volume of pores, but, on crusting, the particles became densely packed with negligible air‐spaces. Soil particles on die surface of the crust showed some degree of orientation but below the surface there was no such tendency, although particles coalesced with negligible air‐spaces. The liquid petroleum mulch prevented crust formation and maintained a stable soil structure.