Search Results (4)

This paper presents analyses of the potential use of Sentinel-1 (S-1) and Sentinel-2 (S-2) imagery to generate models of winter wheat growth under agricultural drought vs. normal conditions identified based on potential yield losses calculated in the Agricultural Drought Monitoring System (ADMS). The analyses carried out showed the sensitivity of satellite images to agricultural drought conditions determined in ADMS. The study was conducted in a large region, the West Pomeranian Voivodeship (NUTS PL42), and the analysis covered about 22,935 polygons with winter wheat production that constituted a total area of about 108,000 ha in the period from the 1st of April to the 1st of July 2021. For S-1 data, VH and VV backscatter and the VH/VV ratio were calculated, and for S-2 data, NDVI and NDWI indices were calculated, which were used to build models of winter wheat growth under water stress and in normal conditions. The obtained results presented in this work include: (i) Development of a test version of a model describing the winter wheat crop’s growth, with a preliminary assessment showing the potential for recognizing water shortage effects; and (ii) identification of promising indicators of water scarcity for crops, calculated based on S-1 and S-2 images, that could be recommended for application in remote sensing (RS) of drought effects as complementary multispectral and radar observations. The results obtained in this work also gave many clues regarding the direction and method of including satellite remote sensing in national monitoring programmes, which involves operations on many types of big data sets. Full article

The properties of soil constitute one of the most important features of the environment that determine the potential for food production in a given region. Knowledge of the soil texture and agroclimate allows for the proper selection of species and agrotechnics in plant production. However, in contrast to the agroclimate, the soil may show a large spatial variation of physical and chemical characteristics within the plot. In regions where the soil diversity is so high that the available soil maps are not sufficient, the only method that allows for precise mapping of the soil mosaic is remote sensing. This paper presents the concepts of using Sentinel-2 multispectral satellite images to detail the available soil-agriculture map at a scale of 1:25,000. In the presented work, the following research hypothesis has been formulated: spatial and temporal analysis of high-resolution satellite images can be used to improve the quality of a large-scale archival soil-agriculture map. It is possible due to the spatial differentiation of the spectral reflection from the field (canopy), which is influenced by soil conditions—especially the differentiation of physical properties (granulometric composition) in soil profiles which determine the possibility of water retention during drought conditions. The research carried out as a case study of maize remote sensing confirmed the hypothesis. It was based on the selection of the most appropriate term (maize development period: BBCH 79, 6-decade drought index: CBW = −206 mm) and the vegetation index (NDVI). This made it possible to make the scale of the map 10 times more detailed. The obtained results are the first step in developing a general model (based on remote sensing) for detailing the soil-agriculture map for Poland, which will significantly improve the accuracy of the drought monitoring system developed by the Institute of Soil Science and Plant Cultivation (Poland). Full article

The aim of this study is to compare the farmers’ viewpoint on agricultural drought with the results generated by the national Agricultural Drought Monitoring System (ADMS) in 2021. The authors attempted also to indicate effective methods of validating these results, which could serve as an objective tool of appeal made available to farmers as a part of an administrative procedure or directly included in the drought monitoring system, which, apart from soil and meteorological conditions, would take into account the actual condition of crops in the field. An analysis comparing farmers’ assessments with the ADMS results was presented for all (27,580 parcels) claims for compensation for losses in winter wheat crops submitted in the country. A detailed assessment of the impact of drought on yields was carried out for two pilot regions in the area most affected by agricultural drought in Poland (West Pomeranian Voivodeship, NUTS-2 PL42 region). The paper demonstrates a subjective assessment of incurred losses, performed by the farmers themselves. The difference between the “potential drought”—resulting from the meteorological and soil conditions—and the actual losses, which are also influenced by agro-technical factors, was indicated. The grounds for further development of the Agricultural Drought Monitoring System were the need to establish a method of estimating the impact of drought on crops, which will be based on unambiguous criteria and using high-resolution (temporal and spatial) remote sensing data. Full article

The current Polish Agricultural Drought Monitoring System (ADMS) adopted Climatic Water Balance (CWB) as the main indicator of crop losses caused by drought conditions. All meteorological data needed for CWB assessment are provided by the ground meteorological stations network. In 2018, the network consisted of 665 stations, among which in only 58 stations full weather parameters were registered. Therefore, only these stations offered a possibility to estimate the exact values of potential evapotranspiration, which is a component of the CWB algorithm. This limitation affects the quality of CWB raster maps, interpolated on the basis of the meteorological stations network for the entire country. However, the interpolation process itself may introduce errors; therefore, the adaptation of satellite data (that are spatially continuous) should be taken into account, even if the lack of data due to cloudiness remains a serious problem. In this paper, we involved the remote sensing data from MODIS instrument and considered the ability to integrate those data with values determined by using ground measurements. The paper presents results of comparisons for the CWB index assessed using ground station data and those obtained from potential evapotranspiration as the product from Moderate Resolution Imaging Spectroradiometer (MODIS) remote sensing instrument. The comparisons of results were performed for specific points (locations of ground stations) and were expressed by differences in means values. Analysis of Pearson’s correlation coefficient (r), Mann–Kendal trend test (Z-index), mean absolute error (MAE) and root mean square error (RMSE) for ten years’ series were evaluated and are presented. In addition, the basic spatial interpretation of results has been proposed. The correlation test revealed the r coefficient in the range from 0.06 to 0.68. The results show good trend agreement in time between two types of CWB with constantly higher values of this index, which is estimated using ground measurement data. In results for 34 (from 43 analyzed) stations the Mann–Kendal test provide the consistent trend, and only nine trends were inconsistent. Analyses revealed that the disagreement between the two considered indices (determined in different ways) increased significantly in the warmer period with a significant break point between R7 and R8 that falls at the end of May for each examined year. The value of MAE varied from 80 mm to 135 mm. Full article