Balance of Nutrients and the Optimization of Their Use in Agroecosystems of the Russian Federation

Abstract

Nutrient balance, calculated at the national and regional level, is a useful tool to gain information on trends in nutrient depletion or enrichment which can be used to choose nutrient management strategies and to assess the undesirable effects of nutrient mining and environmental pollution. The balances of the main plant nutrients like nitrogen (N), phosphorus (P), and potassium (K) were calculated by taking into consideration the inputs of nutrients with mineral and organic fertilizers, seeds, biologically fixed N (symbiotic and non-symbiotic fixation) and rain, plus the outputs of nutrients through crop uptake, and losses through leaching, erosion, and denitrification. The increase in the scope of chemicalization in Russia led to the gradual elimination of the N and P deficit, and the surplus of these nutrients at the national level—from the approximate balance since the mid-1960s up to 37 and 25 kg/ha and between 1986 and 1990, respectively. The annual deficit of K was also gradually reduced in the same period from −15 to −2 kg/ha. Present-day agriculture has a serious annual excess of removal over input, with a long-term deficit of up to 30, 10, and 27 kg/ha for N, P, and K, respectively as the result of a drastic decrease in mineral and organic fertilization, since the 1990s. The regional balance also provides a link with monitoring data of nutrient availability in arable soils. For the regions with high-input agricultural production, the analysis of agrochemical survey data shows a consistent decrease in the weighted average content of available P and K forms in arable lands. This negative tendency became clear when the input of nutrients was inadequate to maintain soil fertility, being permanently lower than its removal from the agrolandscapes. The balance method helped to identify hot spots of unbalanced fertilization, where N consumption outstripped that of P and K. Siberia is one of these regions where arable lands are not only underfertilized, but mainly receive N fertilizers at the expense of P and K as a result of farmers concentrating on short-term decisions instead of long-term sustainability, while in the Russian Far East the situation is much more favorable. The development of policies and strategies relating to the fertilization requirements of Russian agriculture should be based on providing balanced nutrition conditions for sustaining agricultural systems and soil fertility conservation.