Organic soil amendments improve microbial activity and reduce the negative effects of salinity and water-logging in soil
Increasing soil salinity threatens soil health and plant growth by altering soil organic matter and organisms that cycle nutrients. A new study in Frontiers in Sustainable Food Systems found that adding organic soil amendments to salty soil increases microbial activity and reduces the negative impacts of salinization. Salinization can occur naturally as climate change increases sea levels and saltwater intrudes into farmland. It also can be caused by human activities such as irrigating dry farmland, where salts accumulate in the soil over time. The researchers in this study tested the effects of adding organic soil amendments on soil carbon availability and microbial activity to water-logged, salty soil mimicking rice production conditions. They added treatments of rice straw, manure or a mixture of both to soils with 50% and 100% water-holding capacity and then added salt to half the samples. Soil respiration (Carbon Dioxide off-gassing) was measured throughout the 34-day experiment. At the end of the experimental period, organic Carbon, inorganic Nitrogen, microbial biomass, and communities of soil bacteria and fungi were measured. The mixed straw and manure treatment was the most effective at maintaining microbial activity with increased water-logging and increased salinity. These results show the importance of including organic soil amendments, the tenet of organic farming, to rice production to reduce negative impacts of salinization.
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