{'fraction_non_alphanumeric': 0.01607565011820331, 'fraction_numerical': 0.005200945626477541, 'mean_word_length': 5.3927492447129906, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Nutrient regime of irrigated meadow-chernozem soils under long-term intensive use

The patterns of phosphorus and potassium status of soils were studied given the improvement of agricultural technologies of irrigated agriculture. Long-term studies were carried out in an experimental grain-grass crop rotation on irrigated meadow-chernozem soil. The experimental plot is located in the southern forest-steppe of Omsk region. Intensive use of irrigated arable land with a rational combination of moisture and mineral nutrition regimes contributes to obtaining maximum yields of forage and grain crops. The creation of various conditions for mineral nutrition due to an increased and high supply of mobile phosphorus and with the application of different options of agricultural technologies made it possible to simulate possible agro-ecological conditions that form contrasting indices of crop productivity. A comparative assessment of the effectiveness of various agricultural approaches to growing crops under irrigation conditions indicates that soil cultivation techniques and forecrops did not significantly affect the content of available phosphorus in the soil. The equilibrium content of mobile phosphorus given a long-term negative balance changed insignificantly. The systematic application of phosphorus-containing fertilizers significantly increased the phosphate status of the soil. However, an adequate assessment of the phosphate status of arable soils is possible using several diagnostic indices (methods). Long-term intensive use of irrigated arable land has reduced the reserves of easily exchangeable potassium from 4 to 1–2 mg/100 g of soil in the arable layer. The content of exchangeable potassium has also decreased by almost 2 times, but the soil remains in a high and very high class of its availability. However, a number of indicators show its increasing depletion in the most mobile fractions of soil potassium. The reserves of non-exchangeable potassium are more stable, which have decreased by about 19% over 40 years, and the soil has passed into the category with an unstable supply.