Abstract
The article discusses a method for diagnosing nitrogen nutrition of spring barley (Hordeum vulgare L.) in different phases of the growing season using a photometric device (N-tester) Yara. The studies were carried out in the conditions of the Moscow region (Russia) on the Mikhailovsky spring barley variety on sod-podzolic medium loamy soils with a high and medium content of phosphorus and potassium and a low content of humus (1.9). The agrometeorological conditions of the growing season of spring barley were characterized by sharp fluctuations in air temperature and the amount of precipitation over decades of the month and in comparison with average long-term observations. Abundant and prolonged precipitation during the grain ripening phase led to lodging in most of the experiments, which affected the yield. To diagnose crops, a model experiment was laid with the introduction of increasing doses of nitrogen fertilizers into pre-sowing cultivation with a step of 30, at which the dose of nitrogen ranged from 30 to 150 kg/ha. Diagnostics was carried out in three phases of vegetation: tube emergence ((Z42), earing (Z55), milk ripeness of grain (Z73) with the Yara N-tester and with the help of stem diagnostics according to the modified method of V. Zerling. The results of photometric diagnostics in the stemming phase (Z42) have a strong correlation with the yield of spring barley grain and with the results of stem diagnostics (R = 0.85). Wherein, the N-tester readings in the earing phase (Z55) and milk ripeness of grain (Z73) with yield R = 0.23 and R = 0.17, respectively, have a weak correlation. This is possibly due to lodging of crops and a change in yield, not as a result of poor plant nutrition, but with difficult mechanized harvesting.
Highlights
Modern agriculture, like many other industries, is moving along the path of automation
When carrying out stem diagnostics in the tube exit phase (Z42), fairly high results were obtained in options of the experiment with fertilizing in doses of 90 kg/ha nitrogen, which amounted to 2.5-2.6 points
In the phase of milky grain ripeness (Z73), when green leaves remained on the plants only in the upper tier, the indicators of stem diagnostics significantly decreased and averaged 0.48 points (Table 1)
Summary
Like many other industries, is moving along the path of automation. The most popular in recent years have received devices that allow quickly, without violating the integrity of agricultural plants to assess its physiological state by optical properties [1]. Plant chemical diagnostics makes it possible to determine the supply of plants with micro- or macroelements in the process of crop formation at one stage or another of development. It is tissue, in which fresh plant samples are analyzed without ashing in the laboratory, and leaf, according to which the total content of elements in the sample after ashing of leaves or other plant parts is determined [4, 5]. Application of plant diagnostics is complicated by the need for laboratory equipment or skills in working with acids in laboratory or field experiments
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