Validation of topsoil texture derived from agricultural soil maps by current dense soil sampling

Abstract

Agricultural soil maps were created to facilitate the management of fields. Such maps, at very large scale (1:5000), cover almost the entire agricultural land in Poland. These maps can be very useful for precision field management. However, they were prepared about 40–50 years ago using old mapping techniques with mainly field (organoleptic) examination of soil. For this reason it is necessary to verify agreement between such maps with the current soil status. In the case of detection of disagreements it is important to identify the causes and propose methods for improving soil maps. Only few studies were made in this aspect. The soil texture (ST) of the upper layer, as presented on the agricultural soil maps from the 1960s and 1970s, was compared with the actual ST of the same four fields in northern and central Poland. For laboratory ST determination, soil samples were collected in a dense sampling network. On average, the agreement of the ST presented on the agricultural soil maps and determined in this study was classified as medium for three fields and good for one field. However, the presence of field areas with poor agreement between the ST determined in this study and that shown on the agricultural maps was detected in all investigated fields. Identified causes for this comprised imprecision of ST determination using the organoleptic method, the generalization of the soil quality maps, and erosion processes during the years between soil mapping and this investigation. The improvement of ST presentation on the large scale soil maps might be achieved by quite denser soil sampling for ST analysis supported by ECa, yield and NDVI maps.

Impact of cultivar and environment soil suitability on the contribution of yield components to grain yield variation in spring wheat

“…The second group of experimental locations (unfavorable) consisted of environments with lower suitability for wheat cultivation and increased susceptibility to water deficits for plants with an average soil quality index of 0.61 (range = 0.47-0.70) ( Table 1). The lower soil suitability most frequently results from coarser soil texture caused by a lower content of fine particles (<0.02 mm) (Stępień et al, 2016), and in a temperate climate zone, it is related to periodic water stress conditions, especially for spring cereals. The effect of water shortages depends on the time of their occurrence.…”

Assessing Multiple Years’ Spatial Variability of Crop Yields Using Satellite Vegetation Indices

“…To represent the relative similarity between them, remote imagery and crop yield data were classified from lowest to highest values into five classes (i.e., quintiles) of equal frequency over the entire field. Then, the correspondence levels and final agreement (%) between each VI and GY were determined as described by Stępień et al [71]: For a given pixel, if the class of VI quantile was the same as that of GY quantile, the correspondence was considered 'high' with value 1; if the class of VI and GY belonged to adjacent quantiles, the correspondence was considered 'medium' with value 0.5; if the class of VI and GY quantile were separated by more than one class, the correspondence was considered 'low' with value 0. Based on this, final agreement was calculated as the sum of pixel agreement scores, according to the formula:…”