Soil, Leaf and Root Ecological Stoichiometry of Caragana korshinskii on the Loess Plateau of China in Relation to Plantation Age

Abstract

Caragana korshinskii, a leguminous shrub, a common specie, is widely planted to prevent soil erosion on the Loess Plateau. The objective of this study was to determine how the plantation ages affected soil, leaf and root nutrients and ecological stoichiometry. The chronosequence ages of C. korshinskii plantations selected for this study were 10, 20 and 30 years. Soil organic carbon (SOC) and soil total nitrogen (STN) of C. korshinskii plantations significantly increased with increase in the chronosequence age. However, soil total phosphorous (STP) was not affected by the chronosequence age. The soil C: N ratio decreased and the soil C: P and N: P ratios increased with increasing plantation age. The leaf and root concentrations of C, N, and P increased and the ratios C: N, C: P, and N: P decreased with age increase. Leaf N: P ratios were >20, indicating that P was the main factor limiting the growth of C. korshinskii. This study also demonstrated that the regeneration of natural grassland (NG) effectively preserved and enhanced soil nutrient contents. Compared with NG, shrub lands (C. korshinskii) had much lower soil nutrient concentrations, especially for long (>20 years) chronosequence age. Thus, the regeneration of natural grassland is an ecologically beneficial practice for the recovery of degraded soils in this area.

Does Caragana korshinskii plantation increase soil carbon continuously in a water‐limited landscape on the Loess Plateau, China?

“…Afforestation of drylands by nitrogen‐fixing shrubs is widely expected to soil carbon sequestration by alleviating nitrogen shortages (Houlton et al, ). Numerous studies have demonstrated that afforestation of legume shrubs increase soil carbon and nitrogen sinks synchronously (Resh, Dan, & Parrotta, ; Shi et al, ; Zeng et al, ). However, our results indicated that initial elevated STN stock by afforestation was decreased in older plantations, indicating a limiting effect on long‐term carbon sequestration.…”

“…Afforestation soil may accumulate low‐quality plant litter input with rich recalcitrant carbon, causing slower microbial decomposition, and ultimately decrease soil nitrogen stock (Li, Zhu, Zhang, & Cheng, ; Templer, Groffman, Flecker, & Power, ). Nevertheless, enriched leaf nitrogen of C. korshinskii with plantation ages and its relatively labile litter in the adjacent locations (Zeng et al, ) suggested that afforestation‐induced recalcitrant carbon input was unlikely a mechanism regulating the negative STN stock response. Alternatively, plant with high nitrogen residence time reduces the annual flux of nitrogen from the plant pool back to the soil pool (Laungani & Knops, ).…”

“…This study was conducted at Shanghuang Village of Guyuan located in the hilly‐gully region of Loess Plateau, China (35°59′–36°02′N, 106°26′–106°30′E, 1,530–1,822 m a.s.l.). The semiarid area occupies 8.19 ha on Entisols (Chinese Soil Taxonomy, ) with 26.6% clay, 62.0% silt, and 11.4% sand (Wang et al, ; Zeng et al, ). Mean annual temperature and precipitation were 6.9°C and 419 mm, respectively.…”

“…Caragana korshinskii, associated with drought tolerance, is often taken to be broadly applicable to a wide range of semiarid areas (Deng, Han, Zhang, Tang, & Shangguan, 2017). Many studies have observed that the C. korshinskii plantation improved soil carbon sink and soil nutrient availability (Cheng, Xue, Xiang, Darboux, & An, 2015;Shi, Han, Zhang, Ding, & Ma, 2015;Zeng, Lal, Chen, & An, 2017). This nitrogen-fixing plant alleviates nitrogen shortage by acquiring atmospheric nitrogen, which leads to soil carbon accumulation (Houlton, Wang, Vitousek, & Field, 2008).…”

Relationship between ecological stoichiometry and community diversity of plant ecosystems in the upper reaches of the Tarim River, China

“…And the rare researches that pay attention to desert ecosystems. Many researches contents is about the C, N, P concentrations and the ratios of plants at the organ and individual levels, which also get the results that C, N, P concentrations and their ratios of different organs were significantly different, the different individuals too (Zeng Q et al . 2017; Halvorson H M et al .…”