Organic Agriculture: Geostatistical methods to evaluate the response of cherry tomato to soil nitrate

Abstract

The organic farming is characterized by high variance in abundance of soil nutrients and subsequent crop output. This high heterogeneity challenges the ability to locate lacks and surpluses of soil nutrients in the agricultural plots using the conventional analytical tools. In order to define these areas, we have used spatial  tools based on kriging interpolation that allow constructing value maps of soil minerals and crop factors based on limited samples. We applied this advanced methodology to an organic greenhouse of cherry tomatoes Solanum lycopersicum var. cerasiforme and to a conventional greenhouse nearby that served as a control. Using these tools we defined the spatial patterns of the organic greenhouse area and succeeded in locating areas of lacks and excesses of nitrates. Overlapping the soil's nitrate values all over the tested area with the cherry tomatoes' growth, yield and physical parameters of the tested plot led to dentification of plant-soil interactions that were defined, till implementation of this methodology, only by the conventional analysis methods [based on ‘Random Blocks’]. The high confidence of the results together with the compatibility of those documented in former studies indicated the validity of the applied spatial evaluation methods for studying the organic practice patterns.