Saturday, 15 July 2006

Ecological Monitoring of the South Russian Plants Nutriment Quality.

Olga Biryukova1, Natalya Kravtsova1, Ivan Yel’nikov2, and Vladimir Kryshchenko1. (1) Rostov State Univ, Bolschaya Sadovaya, Rostov -on- Don, Russia, (2) Soil Institute after V.V. Dokuchaev, Pyghevski, Moskow, Russia

The notion of ‘nutriment quality' not only embraces the optimum level of chemical elements content in plants, but also its optimum ratio (balance) within the complete vegetation period. These days plants nutriment quality factors should be used as universal criteria for the assessment of the environmental danger level conditioned by soil degradation and soil covering changes, various man-caused and agrogenic impacts upon the soil and plants. The common soil fertility criterion, which is the harvest, fails to characterize the vegetal produce quality, which may vary from a not dangerous level to a highly dangerous level with quantitatively equal harvests. The generally accepted criteria for the assessment of the environmental dan-ger of the vegetal produce and soil (Maximum Permissible Concentrations, or MPCs) are ineffective since they characterize the pre-pathological or pathological states of the subject of study. They also fail to completely assess the environmental danger linked not with the distur-bance of concentration, but rather with the balance in the vegetal produce chemistry. Besides, MPCs do not depend on the soil characteristics, hence they do not let forecast the hidden environmental danger at its early stage, when its removal is still possible. Various microbiological and biological tests do not characterize the ecological condition of the full root-inhabited soil layer, they only show the place where the soil sampling was done. These are typically generalizing criteria, which cannot serve as a basis to determine, which definite nutriment element or group of elements deteriorates the vegetal produce quality. Farming ecologization in fact means plants mineral nutriment with a large number of macro- and microelements. This re-quires a thorough regard of the influence of at least the basic soil factors upon their receipt by plants. The modern oncoming global environmental threat and universal intensive degradation development and contamination of soil require annual regional monitoring of the plants nutri-ment quality. Under the South Russian conditions systematic and experimental studies in this direction were started by the Soil Science and Agricultural Chemistry Department of Rostov State University, together with Soil Institute after V.V. Dokuchaev. Monitoring with a coupled soil-and-plant analysis is carried out on the basis of a multiple-unit diagnostics method (the ISOD system). Formed have been databases with maize, sorgo, wheat, carrot, soy, barley with an analysis of up to 20 macro- and microelements content in them. The research results have shown that in the South of Russia various in their biological characteristics species of plants, in spite of their frequently insufficient supply with moisture, strongly react to the degrading changes of soil properties and fertilization, by changing their nutriment quality in a large number of macro- and microelements at the early stages of their development. These disturbances cannot be removed at the development phases, which follow, and this leads to a highly possible correlative dependence between the final harvest magnitude / its quality and the plants nutriment disturbance at the early period of their development. By the example of sorgo, wheat, carrot studies, we have shown that the above dependence may be expressed as plural regression models. A practical use of such models enables, at a multiple-factor basis and at early plant development stage, to forecast the possible harvest magnitude and quality, as well as to assess the optimum fertilizer dose not just in what concerns the fertilizer influence on the harvest magnitude, but also in the change of environmentally important (P/Ca, Sr/Ca, K/Ca+Mg, Fe/Mn, etc.) chemical elements ratio in the harvest. Monitoring of the plants nutriment quality directly in industrial crops should be carried out at specially allocated agrolandscapes in view of the space heterogeneity of the soil covering and the soil characteristics microdiversity. In prospect, one should form a static geographi-cal network of ‘soil-plant' biomonitors with annual monitoring of the plants nutriment quality of a large number of macro- and microelements, which will permit to estimate the mathematical models of diagnosing the changes in soil efficient fertility and plants nutriment quality within a timing loop.

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