Application of Crop Residues in Combination with a Mineral Nitrogen Fertilizer to Albic Retisols and Their Effect on the Nitrous Oxide Production

• Published in: Moscow University soil science bulletin 2022, Vol.77 (1), p.46-52
• Main Authors: Maslov, M. N., Pozdnyakov, L. A.
• Format: Article
• Language: English
• Subjects: Biomass; Carbon content; Cereal crops; Crop residues; Crops; Decomposition; Earth and Environmental Science; Earth Sciences; Emission; Emissions; Fertilizers; Historical Geology; Immobilization; Microorganisms; Mineral fertilizers; Mineralization; Nitrogen; Nitrogen compounds; Nitrous oxide; Organic nitrogen; Paleontology; Parameter identification; Residues; Rye straw; Soil dynamics; Soils; Straw; Substrates
• ISSN: 0147-6874; 1934-7928
• DOI: 10.3103/S0147687422010057

A laboratory incubation experiment was conducted to examine the effect from the application of crop residues (rye straw) in combination with a mineral nitrogen fertilizer on the production of nitrous oxide in Albic Retisols. A linear correlation between the weight of plant residues applied to the soil and the increase in the microbial carbon content in this soil has been identified. An important parameter characterizing the studied system was the soil microbial biomass C : N ratio and its dynamics (both determined by changes in the amount of applied crop residues and temporal dynamics). If the C : N ratio in plant residues exceeded 40 at early stages of their decomposition in the soil, a change of predominant process has been shown: microbial immobilization of nitrogen is replaced by mineralization of organic nitrogen compounds. It has been shown that the maximum nitrogen immobilization ‘capacity’ of microbial biomass is achieved when the C : N ratio in the substrate was 20–40. A relationship between the nitrous oxide emission from the soil and the amount of crop residues applied to this soil has been identified. It was established that the emission factor (i.e., N 2 O amount produced per 1 g of applied C) reached maximum values in experimental variants involving the application of substrate enriched with nitrogen (C : N = 7.5–10); apparently, this was because better nitrogen supply conditions contributed to a faster and more complete decomposition of plant residues.