Application of Fertilizers and Change of Enzymatic Activity of Soils

As a result of experimental research it has been found that piedmont irrigated chestnut soils of Zailiyskiy Alatau in natural conditions are characterized by moderate activity of hydrolytic and redox enzymes. Crop rotation raises hydrolytic activity of enzymes' groups (invertase, urease, ATPase) by 30% in comparison with monoculture, but at the same time it does not have a significant impact on change of biological activity of redox enzymes (catalase, dehydrogenase). Hydrolytic activity of soils is activated to a greater extent in crop rotation, by monoculture and background of organic system of fertilizers. Therewith, mineral systems of fertilizers don't inhibit activity of hydrolytic and redox enzymes under recommended norms. Increment of hydrolytic activity of soils has a direct impact on level of yield capacity of oilseed flax. Thereupon, indices of hydrolytic activity of soils can be used as a test for diagnosis of efficiency of fertilizers systems both within crop rotation and by monoculture

Stocks and fraction composition of phosphorus in the Ili Alatau foothill soils and their change under long-term use

In soils of Ili Alatau (dark kastanozems, light kastanozems, mountain chernozems) both in continuous cropping system of sugar beet and in crop rotation with prolonged use of fertilizers the soil agrochemical indices, phosphorus reserves and group composition (total, organic and mineral) vary significantly. The total phosphorus content in the soils was 1720–2330 mg/kg and decreased in the series: virgin mountain chernozems > arable dark kastanozems > arable mountain chernozems > light kashtanozems > virgin dark kastanozems. It was observed, that in arable dark kastanozems, as compared to virgin soils, the content of available forms of phosphorus (loose-bound phosphates Ca-PI and miscellaneous calcium phosphates Ca-PII) increased, and the content of plant unavailable forms of phosphorus (poorly soluble Ca phosphates Ca-PIII, phosphates of aluminum Al-P and iron Fe-P) decreased. In arable mountain chernozems, in comparison with virgin mountain chernozems, the content of all fractions of phosphorus decreased. Arable light kastanozems contain the least amount of available phosphates and the highest of phosphates of aluminum and iron. When cultivating beets on light kastanozems, the content of all fractions of phosphorus, except iron phosphates, increased with increasing dose of fertilizers. The effectiveness of the application of the organic-mineral fertilizers was comparable to the introduction of NK + P1.5 and NK + P2, the yield of sugar beet in the crop rotation in these variants is the highest and amounts to 614 and 577 centner/ha; in the control value (obtained without fertilizers) – 197 centner/ha, and in the variant with application of only NK fertilizers – 277 centner/ha. In continuous cropping system these values were 576 and 561 centner/ha; 311 and 327 centner/ha respectively. Close values of crop yield were obtained in two variants: with the organo-mineral system and NK + P1.5, due to the additional use by the plants of sugar beet phosphorus of newly formed organic compounds