Title : Large role of small relief elements in precision agriculture
Abstract:
The implementation of "precision farming" into practice requires a detailed quantitative assessment of the soil cover heterogeneity. Such an assessment is carried out mainly by the provision of soils with gross and mobile forms of nutrients, the presence of toxic substances, the degree of erosion, that is, by dynamic indicators. In the course of 2008-2022, we are studying the spatial heterogeneity of the fundamental indicators of soil cover on the plains of the forest-steppe and steppe zones with chernozems (“black soil”), due to the presence of a micro-relief. It is the presence of relief micro-depressions (“potholes”) that causes the spatial heterogeneity of the water regime of soils on such plains, and, as a result, the heterogeneity of the soil cover. Detailed soil studies using Landsat and Sentinel satellite images, a quadcopter, a GPS receiver and chemical analyzes showed that the soils shown on ordinary soil maps occupy no more than 40-50% of the field area. Detailed soil studies using Landsat and Sentinel satellite images, a quad copter (UAV), a GPS receiver and chemical analyzes showed that the soils shown on ordinary soil maps occupy no more than 40-50% of the field area. The rest of the area is occupied by semi-hydromorphic and even hydromorphic soils, which are formed due to the redistribution of moisture over the micro-relief, primarily during the snowmelt period in spring with the formation of temporary lakes that exist from 2 to 4 weeks, depending on the water reserves in the snow and weather conditions during the snowmelt period. The moisture of summer precipitation is also redistributed over the elements of the micro-relief, contributing to the heterogeneity of the water regime and soil properties and their different productivity. In the fields with winter wheat, the yield at the bottom of the micro-depressions with a depth of about 50 cm was about 30%, and on their slopes - 60-80% of the yield in the flat areas of the field. The ripening of wheat in micro-depressions occurs 1-2 weeks later, which affects the timing of harvesting and the quality of grain. In general, the loss of wheat yield in the studied fields (depending on the area of ??micro-depressions) was about 30%. On the slopes and bottoms of micro-depressions, weed infestation and weediness of wheat plants increased. Similar yield losses were identified in the fields of alfalfa, barley, sugar beet, but their reliable quantitative assessment is still ongoing. Proposals are being developed to improve agricultural technology in fields with micro-relief, in particular, the introduction of deep loosening of soils in micro-depressions. The distribution of micro-depressions is also analyzed in the forest-steppe and steppe zones of Eurasia, and a refinement of soil maps is proposed in connection with the spatial heterogeneity of the soil cover on plains with micro-relief. The results of the study are of significant ecological and economic importance.
