Effects of tillage practice on fungal and actinobacterial cellulolytic community with different humified particle‐size fractions in a double‐cropping paddy field

Abstract Soil cellulose plays a vital role in keeping or increasing carbon (C) cycling and fertility of rice fields. There is a close relation between soil fulvic acid (FA), humin (HM) fractions, and GH48 , cbhI genes. However, the effects of different tillage practices on soil humus C content composition, GH48, and cbhI genes abundances in different soil particle‐size fractions of double‐cropping rice fields still need to be further investigated. Therefore, the impacts of different short‐term tillage practices on soil GH48 and cbhI genes abundances in double‐cropping rice fields were conducted. This experiment set up different tillage practices: rotary tillage with crop straw removed as a control (RTO), conventional tillage with crop straw in put (CT), rotary tillage with crop straw in put (RT), and no‐tillage with crop straw retain (NT). The result indicated that the distribution of soil humus, and GH48 , cbhI genes abundances were significantly enhanced under combined applied with tillage and crop straw incorporation conditions. Soil FA, HM, and humic acid (HA) C content in 2000–50 μm and >2000 μm fractions with RTO treatment were significantly lower than that of CT, RT, and NT treatments. This result showed that oalkyl and alkyl of HA and FA in 2000–200, 200–50, 50–2, and 2–0.1 μm fractions with CT, RT, NT, and RTO treatments were lower than that of >2000 μm fraction. There was lower ARO% and more AL% of FA and HA in these fractions under the same tillage condition. The result showed that GH48 and cbhI genes abundances in these fractions with CT, RT, and NT treatments were significantly higher than that of RTO treatment. There had significantly positively correlated with GH48 , cbhI genes abundances, and soil HA, FA, HM C contents, o‐alkyl C, and AL% of FA. Therefore, it was positively practiced for increasing GH48 and cbhI genes abundances in the double‐cropping rice fields by applying with tillage and crop straw incorporation.