“Vernal dam” in Temperate Deserts

Desert soils are often characterized by low nutrient status, and plant nutrient conservation is of great importance to plant growth and the performance of ecosystem functions. Spring ephemerals are one of the most important constituents of plant communities in Central Asia. They show a fast growth rate and the dominance of ephemeral biomass in the herbaceous community in spring-early summer may lead them to be the most important agent of soil nutrient uptake. However, their role in desert soil nutrient retention has not been investigated. 

HUANG Gang and his colleagues from the Xinjiang Institute of Ecology and Geography (XIEG) of the Chinese Academy of Sciences focused their research on the topic and found that desert spring ephemerals play a key role in the nutrient retention and absorption of arid ecosystems. 

HUANG carried out his research in the Gurbantonggut Desert in Central Asia, a typical temperate desert where the vegetation comprises sparsely distributed shrubs and a dense cover of herbs. For three straight years from 2011 to 2013, scientists measured the seasonal patterns of spring ephemerals and the soil microbes’ uptake of N and P, main nutrient elements of the soil. 

“Ephemerals exhibited a net N and P uptake of 0.49-0.94 g N m-2 and 0.05-0.09 g P m-2 in the normal precipitation years, and released 35% of litter N and 60% of litter P within six months. Microbial immobilization was 3.6 and 4.5 times of spring ephemeral uptake in terms of N and P in the normal precipitation years, but soil microbes showed a nutrient release in the dry year.” said HUANG. 

Their study demonstrates that spring ephemerals can incorporate soil nutrients into plant biomass in the spring and then release nutrients into soil by fast litter decomposition. Moreover, this study also indicates that soil nutrient utilization by spring ephemerals is an important nutrient retention mechanism in the temperate desert and the magnitude of nutrient retention is biomass dependent. 

Their study entitle “The role of spring ephemerals and soil microbes in soil nutrient retention in a temperate desert” was published in Plant Soil.