BIOCHEMICAL METHOD FOR DETERMINING OF EFFECTIVE FERTILITY OF SODDY PODZOLIC SOIL Russian patent published in 2004 - IPC

FIELD: agriculture, agronomical chemistry, agronomical ecology.

SUBSTANCE: method involves composting sample of soil to be analyzed for 7-8 days at temperature of 34-36⁰C; determining mineral nitrogen and nitrogen mobilized from organic substance of soil by boiling of suspension taken from composted sample of soil in an amount of at least 10 g by weight and in the ratio of 1:5 for 20 min for sandy, sandy loamy and medium loamy soils and for 30 min for heavy loamy soil; determining amount of extracted nitrogen in Kieldal apparatus under alkaline hydrolysis condition while adding Devarde alloy; obtaining really accessible nitrogen in arable layer of soil (N_r.a); determining real assimilation thereof by crop on the base of standard coefficients; determining crop yield by amount of nitrogen required for producing of 100 kg/hectare of resultant product from formula: where Y_c is crop yield, 100 kg/hectare; c is really accessible nitrogen required for production of 100 kg/hectare of resultant product, kg/100 kg; Uc is coefficient of utilization of really accessible nitrogen by crop; judging soil fertility level: yield of 800-1,200 kg/hectare of cereals is accepted as low level of fertility, yield of 1,300-2,000 kg/hectare is accepted as average level of fertility and yield of 2,100-4,500 kg/hectare is accepted as high level of fertility. Yield exceeding 4,500 kg/hectare is accepted as very high level of fertility.

EFFECT: reduced number of operations, decreased consumption of reactants and materials, and provision for immediate determination of nitrogen stock really accessible by plants.

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