Crop production is directly related to the temporal and spatial changes of soil moisture. Water and nutrients are the two major resources for crop production (Sharma et al. 1993). The use of available soil moisture by a crop is necessary and this can best be obtained from the accurate description of the distribution of soil moisture in the root zone. Assessment of such a distribution of soil moisture through field measurements is expensive, time consuming and laborious (Sharma et al. 1997).

Based on this fact in our experiment we decided to find solution for the continuous, direct or indirect measurements of soil moisture.

In our examination we carried out various measurements at the same time and with various methods on a field in Mosonmagyaróvár. On the investigated field site-specific crop production was applied since 2001. The instruments applied were as follows:

1. A hand-held Spectrum Field Scout TDR-300 type soil moisture probe further equipped with a data logger and GPS receiver. Data transfer was via RS-232 port, the rods were 20 cm. Due to the additional equipments we could automatically collect volumetric soil moisture data with additional coordinates.

2. The other instrument was a vehicle-pulled specific Veris 3100 Electrical Conductivity meter. This instrument was equipped with GPS-connection too in order to map our field. This tool makes it possible to continuously measure data while in movement, assuring the necessary number and density of data. By the application of this instrument we presumed that based on the electrical conductivity data, soil moisture data can be measured; therefore, continuous soil moisture measurement can be carried out.

In the research we looked for connections between data of the two measurements. We assumed that the on-site measurements will further simplify the soil moisture measurement compared to the laboratory based gravimetric (drying chamber) based slow, time and workforce consuming method. Furthermore, in the case of the strong correlation between the soil electrical conductivity and the soil moisture content, an online measurement method will be available for soil moisture measurement.

According to the measurement data collected at the same time, soil moisture and electrical conductivity maps were created by ArcGIS ArcMap software. The two maps showed virtually very strong relation which was proved by statistical evaluations as well. We compared the data of the two measurements with correlation (minimum r=0,86) and with regression analysis. In the case of field measurements, these results showed strong correlation between the two databases. In the worst case, the correlation was R2=0,7404.

Keywords: precision agriculture, winter wheat, soil moisture, Electrical Conductivity, TDR 300, Veris 3100