Agrogray Soils Research Articles

Temperature field of complex soilscapes (by the example of the Vladimir opolie region)

Problems of the assessment of soil temperature regime at the polypedon level have yet to be solved. An approach suggested by the authors consists of three stages: (1) the characterization and prediction of the soil water regime as a factor influencing the soil temperature regime, (2) the obtaining of thermophysical functions for the particular elements of complex soilscapes, and (3) the calculation and assessment of the temperature regime of complex soilscapes in the form of the functional fields of soil temperature isopleths. This approach has been applied to predict the soil temperature regime of an arable field in the Vladimir opolie region. The complex soilscape of the field consists of medium loamy agrogray soils, agrogray soils with the second humus horizon, and podzolized agrogray soils. At the beginning of the growing season, minimum temperatures are observed in the areas of agrogray soils with the second humus horizon; the difference in soil temperatures at a depth of 20 cm reaches 1°C, and the difference in the sum of active soil temperatures reaches 20°C. Then, this difference changes considerably, so that the agrogray soils with the second humus horizon become warmer than the agrogray soils. In general, the functional field of soil temperatures within the complex soilscape is highly dynamic and diverse, which is specified by the variability in the water-physical and thermophysical properties of particular soils.

Biochemistry of lignin in soils of periodic excessive moistening (from the Example of Agrogray Soils in Opolie Landscapes of the Russian Plain)

Tissues of Angiospermae (deciduous arborous and herbaceous plants) were found to take part in the formation of humus in the agrogray soils. The proportions of lignic phenol contents between the soils did not change neither upon their plowing, no their drainage. Within the catenas studied, the maximal accumulation of phenol compounds takes place in the soils of the mesodepressions with long-term reduction conditions and in the soils of the microdepressions with spring perched water on two levels. In the Fe-Mn nodules of the agrogray soils, lignin of higher plants was found. Its fractional composition was correlated with the predominant vegetation. With the increasing size of the nodules, the amount of products of lignin oxidation in the nodules decreased due to its mineralization. Drainage caused a deep transformation of lignin in the Fe-Mn nodules, especially in the coarse fractions of concretions. The mineralization of lignin aromatic compounds under aerobic conditions was accompanied by the significant increase in the share of phenol acids.

ASSESSMENT OF CONSTITUTIONAL BASE OF AGRO-GREY SOIL FERTILITY

The general state of fertility should be assessed by at least two groups of parameters: dynamic (mobile nutrients, acidity) and constitutional direct - mineralogical, granulometric, organic and chemical composition, as well as constitutional indirect - cation exchange capacity (CEC), sorption capacity, buffering capacity. The purpose of the research is to study and evaluate some of the constitutional parameters of the fertility of the experimental agro-gray soil. The humus content in the soil (2%) corresponds to the minimum permissible level. The soil has a low value of the sum of exchangeable bases (7-8 mmol / 100 g of soil), which is 2 times less than the cultivated analogue. In the soil, the share of free HAs increased to 11.5-14.0% (abs.) And the content of HAs not associated with calcium decreased to 24.3-28.1%. In the mineral part of the thin soil fraction of agro-gray soil 1-5 microns in size in the 0-20 cm layer, the content of functionally inert minerals is 63% in total. The number of valuable mixed-layer formations increases with depth. To compensate for the loss of clay fractions, cover loam enriched in nitrate forms of nitrogen can be used. The experimental product contains about 2.7% of total nitrogen, mobile and total potassium is 1250 mg / kg and 0.20%, respectively, ECO - 48 mg-eq / 100 g.