Effects of rice planting years on physicochemical property and fungi community in soda saline-alkali soil

Objective  To investigate the effects of different rice planting years on physicochemical properties and fungi communities of soda saline-alkali soil, and provide a theoretical basis for saline-alkali soil improvement.

Method  Soda alkali-saline soil that had been planted with rice for 1, 3, 5, 15, 20 and 50 years respectively were chosen as research objects. The routine analysis and IlluminaMiSeq platform sequencing analysis were conducted to study the basic soil physicochemical properties, richness and diversity of fungi in ITS1+ITS2 domain in soda saline-alkali soil with different rice planting year.

Result  With the increase of rice planting year, pH, electrical conductivity, total alkalinity and water soluble total salt of saline-alkali soil decreased significantly; soil organic matter and microbial biomass carbon contents increased significantly; total nitrogen, ammonium nitrogen and nitrate nitrogen contents presented increasing trends; available phosphorus increased significantly first, reaching the maximum in the treatment of planting rice for 20 years, then decreased slightly; and available potassium content had no obvious changing pattern. The effective sequence numbers of fungi obtained in soil with 1-, 3-, 5-, 15-, 20- and 50- year rice planting periods were 56 942, 42 482, 45 987, 92 214, 64 665 and 68 515, including five phyla, 12 classes, 25 orders, 26 families, 45 genera and 59 species. Cladosporium, Holtermanniella and Massariosphaeria were dominant with relative abundance more than 2%. The α diversity indexes first increased and then decreased with the extension of rice planting years, reaching the largest in soil planted with rice for five years. Soil pH, electrical conductivity, total alkalinity, water soluble total salt and available potassium contents were the main environmental factors affecting fungi communities of soda alkali-saline soil after planting rice.

Conclusion  Planting rice can siginificantly change the basic physicochemical properties and fungi community structures of soda alkali-saline soil, and promote soil improvement.