Woody organic amendments for retaining soil water, improving soil properties and enhancing plant growth in desertified soils of Ningxia, China

- Incorporated wood chips improved desertified soil.
- Best treatment was 5% incorporated wood chips plus a twig lattice aboveground.
- Mulch increased water availability, but chips improved microbes and soil structure.
- Wood from local trees can improve soil, save water, and increase crop yields.
- Slow-decomposing wood chips in soil can help sequester carbon.

Extreme soil degradation is one of the most serious problems affecting dryland ecosystem health and agricultural production globally. This study was conducted to investigate the potential for using woody amendments to improve soil moisture availability, soil microbial activity, soil fertility, and plant growth in desertified soils in Ningxia, China. Soil amendments of wood chips derived from tree branches of four readily available tree species (poplar, elm, pagoda tree, and grapevine), were evaluated and compared with more commonly used wheat straw, rice husks, and cow manure, using replicated microcosm experiments. Different types, concentrations, and application techniques of woody and non-woody organic amendments were compared for their impacts on soil moisture, soil chemistry, microbial activity, and plant growth. The treatments with woody organic materials incorporated into the soil consistently demonstrated an improvement in soil water status, increased organic C content, and improved soil fertility, and also resulted in enhanced microbial activity, and wheat growth. Although surface mulch increased soil water storage and enhanced wheat growth, it did not effectively improve soil microbial activity as compared with wood incorporated into the soil. Differences in placement and type of amendment differ markedly in their effects on physical, chemical and biological soil responses. A combination of 5% poplar wood chips incorporated into the soil with a lattice of twigs over the soil was ideal for simultaneously maximizing soil water availability, encouraging microbial activity, and maximizing wheat yield. In conclusion, woody materials from locally available trees can serve as a valuable amendment for desertified soils in Ningxia and other places of Northern China by increasing rainfall capture, reducing irrigation demand, improving soil health and promoting higher crop yields.