Study on Soil Nitrogen and Electrical Conductivity Relationship for Site-Specific Nitrogen Application

Abstract.

The purpose of this work was to develop an algorithm in order to develop a sensor to monitor the available soil nitrogen in the field. The available nitrogen in soil and crop root zone is an essential factor limiting the yield of crops. The crops nitrogen requirement is vary within a field and in different cropping season based on many factors such as; soil type, regain climate, crop needs and crop rotation system. It is profitable and efficient to match crops nitrogen demand to the nitrogen application throughout the season. Three different and common soil types used in agriculture regain, were firstly classified based on the soil triangle chart and an algorithm was developed to determine soil nitrogen requirements in those three different soils. Each soil type chosen to have high percentage of either sand, silt or clay. Physical properties i.e. field capacity, permanent wilting point, available water capacity and chemical properties i.e. pH, available nitrogen and total nitrogen, organic carbon, phosphorus and potassium were determined. Four levels of moisture content keeping in view the best moisture levels between tillage moisture and field capacity were selected. Four levels of nitrogen were selected based on common practice of nitrogen application of 50, 100, 150, 200 kg/ha. Soil moisture levels were measured by moisture sensor as well as oven dry method and the Electrical Conductivity (EC) of these soil samples were measured by using an accurate EC meter (Hanna Soil EC -Tester). A significant relation between electrical conductivity and moisture levels of soil was observed. Also, the relation between electrical conductivity of soil and levels of nitrogen therein was found significant. The relation between EC and different levels of nitrogen in different levels of moisture is going to be used to develop a sensor for real time variable nitrogen application in precision agriculture.