DEPENDENCE OF PHYTOMETRIC PARAMETERS OF AGROCENOSES ON AGROPHYSICAL INDICATORS OF SOIL

An express-evaluation of the level of development of field agrocenoses phytomass and agrophysical soil indicators is necessary for rapid technological optimization of the growing conditions of crops in order to more fully realize their productive potential, as well as to preserve and reproduce soil fertility. The research was carried out in 2020–2022 at the experimental field of the Orenburg State Agrarian University. The objects of research were the normalized difference vegetation index (NDVI) of agrocenoses of winter wheat (Triticum aestivum L.), spring wheat (Triticum aestivum L.), oat (Avena sativa L.) cultivated under minimum tillage technology and soil agrophysical parameters (hardness, humidity, density) at the experimental site. NDVI was determined using remote sensing data and a hand-held sensor Green Seekеr Handheld Crop Sensor, Model HCS–100. The penetrologger Eijkelkamp 06.15.SA was used to determine the hardness of the soil; the density of the arable soil layer was determined by N.A. Kachinsky drilling method; soil moisture was determined by the thermostatic-weight method. Digital material was processed using generally accepted methods of statistical analysis. We have established the acceptability of modern instrumental methods (using portable devices) for determining phytometric parameters of crops and agrophysical properties of soils; the undoubted advantages of these devices are their ease of use and speed of obtaining results. The high convergence between the results of NDVI determination using satellite images and those obtained by ground scanning was confirmed. The dependence of phytometric parameters of oat agrocenosis (according to NDVI) on agrophysical indicators of the soil was revealed. The most pronounced inverse relationship (r = –0.52) was observed between NDVI and the density of the upper soil horizon (5–10 cm), as well as between NDVI and the hardness of the soil layers: 5-10 cm (r = –0.43) and 25–30 cm (r = –0.52). With a certain degree of conditionality, this connection can be explained by the transition to direct sowing in modern agricultural technologies and the legacy of deep tillage in retrospect, which created a compacted soil layer in these horizons