Investigation of soil properties affecting optimum design of pokkali paddy harvester

Abstract

The Pokkali field is a unique eco-system prevailing in the coastal tract of Kerala with rich bio diversity and amazing capacity to produce organic rice and shrimp alternatively. In the saline, water-logged Pokkali farm lands, rice and shrimps are farmed alternatively. During the time of harvest, the fields are almost dry and by the time of harvest, the fields become completely waterlogged. This shift in the moisture regime causes a great variation in the nutrient status of the Pokkali soil. Along with it, changes in soil pH and electrical conductivity play a role in the nutrient dynamics in these soils. The soil samples were collected from eight Pokkali padashekarams of Kottuvally panchayath and RRS, Vyttila Organic carbon, available nitrogen and magnesium showed a decreasing trend from mound preparation to harvest stage. The available nutrients namely P, K, Ca, S, Fe, B, Al and Na followed an increasing trend from mound preparation to harvest stage. Available Zn, Mn and Cu did not show any significant difference between two stages. The study shows that the cone index and shear strength of Pokkali soils decreased with increased depth and decreased with increase in moisture content. For this soil the critical moisture content was found to be 45.9%.