THE COMPREHENSIVE EFFECT OF MICROBIAL METABOLIC DIVERSITY ON CARBON COMPONENT CHANGES IN SALINE ALKALI FARMLAND.

In the face of the reduction of biodiversity in saline alkali farmland and its adverse effects on soil carbon components, experiments were conducted using different sludge treatment gradients (0, 25, 50, 100, 200 t/ha). The changes in functional groups in soil aggregates were quantitatively analyzed using infrared spectroscopy technology, and microbial activity was measured using chemical analysis methods. The results showed that the application of sludge significantly increased the soil macroaggregates' mass fraction, which was 48.9% in untreated soil and increased to 51.1% after the highest treatment gradient. The absorption peak intensity of 3617 cm-1 caused by hydroxyl functional groups significantly increased after application, especially at 150 t/ha. In addition, there was a slight increase in microbial activity in soil aggregates ranging from 0.25 to 2 mm, while microbial activity was significantly enhanced in aggregates larger than 2 mm. The soil salt content indirectly affected the microbial metabolic rate by affecting soil sucrase activity and soil organic carbon, with a path coefficient of -0.42. Salt is a key factor affecting microbial metabolic diversity. Reasonable application of sludge can effectively improve the metabolic diversity of microorganisms in saline alkali soil, promote the formation of soil aggregates, and enhance the fixation soil organic matter. This has practical value in improving the soil structure of saline alkali farmland and promoting sustainable soil management. [ABSTRACT FROM AUTHOR]