Changes in soil organic carbon and nutrient pools in aggregate‐sized fractions along a chronosequence of wolfberry (Lycium barbarum L.) plantations in arid areas of Northwest China

Abstract

Different land use and management actions can affect soil aggregates (SAs) and nutrient stocks, which are crucial for sustainable agriculture. The impacts of various chrono‐sequences on the soil aggregate structure, soil organic carbon (SOC) and nutrients associated with aggregate fractions in wolfberry (Lycium barbarum L.) plantations are still not fully understood. This study examined the composition and stability of SAs, SOC, total nitrogen (TN), available phosphorus (AP) and exchangeable cations (K+, Na+, Ca2+ and Mg2+) in bulk soil and various aggregate‐size fractions from five wolfberry plantations with varying ages (1, 4, 6, 10 and 13 years) and a corn field (0 years) in the arid region of northwest Ningxia in China. The results indicated that silt–clay (<53 μm) fractions were dominant in the soil, accounting for 51%–66%, under different plantation ages. The proportion of the macro‐aggregates (>250 μm) increased significantly, by 40%–47%, over the 4 years of wolfberry plantation. Likewise, the soil aggregate stability was improved, and total exchangeable bases (TEB) along with numerous cations concentrations (K+, Na+, Ca2+ and Mg2+) in SAs were significantly reduced as the wolfberry plantings became older. Both concentrations of SOC and TN in the soil aggregates peaked in the 13th year. The silt–clay fractions stored a considerable amount of SOC and nutrients. However, short‐term (under 6 years) cultivation of wolfberry reduced the stocks of SOC, TN and AP in the soil, while long‐term (over 10 years) cultivation increased them, particularly in macro‐aggregates. These findings indicated that long‐term wolfberry farming had several advantages, such as enhancing soil structure, accumulating SOC and nutrients and ameliorating alkaline soils, especially after 10 years, in the arid northwest of China.

Impacts on Soil and Cowpea Plants Fertigated with Sanitary Sewage through Subsurface Drip Irrigation

“…The information regarding the sodium content available in the soil is insufficient to assess adverse effects on plant growth and development. It is also important to know the proportion concerning other soil cations, such as K + , Ca 2+ , and Mg 2+ [33]. Soils with an SSI lower than 6% are considered non-sodic [34].…”

Planting Year- and Climate-Controlled Soil Aggregate Stability and Soil Fertility in the Karst Region of Southwest China

“…Continuous soil management might alter soil properties, and such change varies across planting years [11,[21][22][23][24][25]. For example, the storage of soil carbon, nitrogen, and phosphorus in tea gardens [11] and ginseng fields [25] increases with an increase in planting years.…”