Main elements of nutrition content in the soil for maize crops, depending on the predecessors and methods of soil treatment
The article presents data on the study of the main nutrition elements in the soil under maize crops, depending on the predecessors and methods of soil treatment in the conditions of ordinary Chernozem. The object of research is a Krasnodarsky 194MV hybrid of maize. Variants: 1. Fallow arable land (control); 2. Lupine as green manure; 3. Peas as green manure; 4. Binary sowing of lupine and peas as green manure; 5. Soy as green manure. The experiment was repeated three times, field placement was randomized, and area of each was 120 m². Agrotechnics of maize cultivation in the experiment corresponded to the recommendations for this zone. Green manure was plowed in during its reproduction phase. In the variants with green mass plowing to a depth of 23–25 cm, the largest amount of nitrate nitrogen was in the soil layer 0–20 cm. In the specified soil horizon, before sowing maize, the content of nitrate nitrogen ranged, depending on the variant, from 24.7 mg/kg to 42.8 mg/kg. In the soil layer 20–40 cm, the amount of nitrogen was lower, just 19.4–29.5 mg/kg. Similar dependence was observed for maize during its flowering phase. Tillage methods had almost no effect on the accumulation of nitrate nitrogen in the upper soil layer (0–20 cm). As in all the variants, the differences in this indicator were within the experimental error. However, the content of nitrate nitrogen during the growing season was different. The greatest amount of it was observed during the spring period, both in versions with plowing to a depth of 25–28 cm and in versions with blade loosening to a depth of 10–12 cm. The smallest amount of available phosphorus, regardless of the method of soil preparation, in the layer 0–20 cm was on fallow arable land – 122 mg/kg during the sowing period and 104 mg/kg during the flowering period. In variants with cultivation of legumes as green manure, the content of available phosphorus in the specified horizon was significantly chigher, being 147–171 mg/kg. The highest content of exchangeable potassium was provided by lupine – 209–213 mg/kg in the 0–20 cm soil layer, and lupine sown together with peas – 196–207 mg/kg. The minimum amount of exchangeable potassium was 143–146 mg/kg in fallow arable land, depending on the method of soil treatment.