METHOD FOR DETERMINING ENVIRONMENTALLY SOUND APPLICATION RATE OF SEWAGE SLUDGE FOR SOIL FERTILIZATION Russian patent published in 2024 - IPC A01C21/00 C05F7/00 

FIELD: agriculture.

SUBSTANCE: invention can be used to improve soil fertility. Method includes laboratory studies of chemical composition of fertilized soils and applied fertilizers from sewage sludge (SS) for gross content of heavy metals and arsenic, on the basis of which the dose of their allowable input into the soil is calculated with subsequent correction for nitrogen content. Qualitative analysis of soils and fertilizers from sewage sludge includes determination of content of benzo(a)pyrene, mercury, mobile forms of heavy metals, microbiological and parasitological parameters. Taking into account all the components, the permissible fertilizer application rate is determined by chemical, microbiological and parasitological indicators in t/ha, maximum possible environmentally sound application rate (AR) and permissible duration of application in one section, according to expression AR_SS = min {AR_T; P_N}, where AR_T = AR_EP/T is the specific, one-time fertilizer application rate, where AR_EP is an environmentally sound rate of fertilizer application, t/ha, and T is the maximum possible period of use of fertilizer on the area under consideration, AR_EP = min {AR_BP, AR_CP}, where AR_BP is the final application rate, based on compliance with soil quality indicators by microbiological indicator, t/ha; AR_CP—final application rate, based on compliance with soil quality indicators for chemicals, including heavy metals in gross and movable forms, t/ha; P_N is the maximum permissible rate of application of the dry substance of the fertilizer, determined by mineral or total nitrogen, t/ha, taking into account its carryover with the annual yield, kg/ha—Y_N and content in fertilizer in mineral form (C_Nmin.) or total amount (C_Ntotal), % of dry substance.

EFFECT: method is environmentally friendly, safe and highly efficient for disposal of sewage sludge accumulated on sludge maps of municipal treatment facilities, prevents pollution of the ecosystem with compounds of heavy metals, benzo(a)pyrene, arsenic and viable eggs of helminths and pathogenic microflora when using sewage sludge as fertilizers, increasing soil fertility due to application of sewage sludge or fertilizers based on them with high content of organic matter, macro- and microelements.

1 cl, 2 dwg, 10 tbl