Long‐term‐fertilization effects on soil organic carbon, physical properties, and wheat yield of a loess soil

Abstract

The large dryland area of the Loess Plateau (China) is subject of developing strategies for a sustainable crop production, e.g., by modifications of nutrient management affecting soil quality and crop productivity. A 19 y long‐term experiment was employed to evaluate the effects of fertilization regimes on soil organic C (SOC) dynamics, soil physical properties, and wheat yield. The SOC content in the top 20 cm soil layer remained unchanged over time under the unfertilized plot (CK), whereas it significantly increased under both inorganic N, P, and K fertilizers (NPK) and combined manure (M) with NPK (MNPK) treatments. After 18 y, the SOC in the MNPK and NPK treatments remained significantly higher than in the control in the top 20 cm and top 10 cm soil layers, respectively. The MNPK‐treated soil retained significant more water than CK at tension ranges from 0 to 0.25 kPa and from 8 to 33 kPa for the 0–5 cm layer. The MNPK‐treated soil also retained markedly more water than the NPK‐treated and CK soils at tensions from 0 to 0.75 kPa and more water than CK from 100 to 300 kPa for the 10–15 cm layer. There were no significant differences of saturated hydraulic conductivity between three treatments both at 0–5 and 10–15 cm depths. In contrast, the unsaturated hydraulic conductivity in the MNPK plot was lower than in the CK plot at depths of 0–5 cm and 10–15 cm. On average, wheat yields were similar under MNPK and NPK treatments and significantly higher than under the CK treatment. Thus, considering soil‐quality conservation and sustainable crop productivity, reasonably combined application of NPK and organic manure is a better nutrient‐management option in this rainfed wheat–fallow cropping system.

The impacts of different long-term fertilization regimes on the bioavailability of arsenic in soil: integrating chemical approach with Escherichia coli arsRp::luc-based biosensor

“…The application of different long-term fertilization regimes could lead to a great change of soil characteristics, such as levels of organic C, P, and the pH (Dong et al 2012;Ge et al 2008;Liu et al 2013;Yang et al 2011;Zheng et al 2008a, b), which could affect the fraction and bioavailability of metal in soil, thereby posing risk to agricultural products. Sequential chemical extraction does not represent the actual bioavailability of As in soil.…”

“…It has been reported that the application of inorganic or organic fertilizers can increase the content of organic carbon in soil and maintain soil productivity (Liu et al 2013;Yang et al 2011). Additionally, it has been confirmed that As mobilization is associated with the concentration of dissolved organic carbon ND not determined in soil, which is due to the organic ligands of dissolved organic carbon (DOC) that facilitate the release of inactive As (F4 fraction) to active soluble As (F1 fraction) through competitive sorption or through solution complexation (Cao et al 2003;Harvey et al 2002;Jackson et al 2006;Mladenov et al 2010).…”

“…However, Li et al (2010) found that the variation of geological source but not exogenous factors played a more dominant role in determining As concentration in soil. However, the application of long-term fertilization increased organic carbon concentration (Liu et al 2013;Yang et al 2011) and the content of phosphorus (P) (Ge et al 2008;Zheng et al 2008a) and changed the acidity of soil depending on the soil conditions (Dong et al 2012;Zheng et al 2008b). Meanwhile, the release of metal including As from the solid phase of soil was influenced by organic carbon based on the formation of soluble metal-organic complexes (Cao et al 2003;Grafe et al 2002;Harvey et al 2002;Jackson et al 2006;Mladenov et al 2010;Wang and Mulligan 2006).…”

“…Different long-term fertilization regimes could lead to a great change of the soil physical and biochemical characteristics such as organic carbon, pH, and P (Ge et al 2008;Liu et al 2013;Yang et al 2011;Zheng et al 2008a), which may cause variation of bioavailable As. There is scant comprehensive research about the impact of long-term fertilization containing N, NP, NPK, M (manure), and NPK + M on the bioavailable As in soils.…”

How does tillage intensity affect soil organic carbon? A systematic review

“…7], indicating that agricultural soils may have a potential to mitigate climate change through C sequestration [8,9]. Besides climate change, SOC has a number of potential associated benefits, including: increased soil fertility [10,11]; improved biological and physical soil characteristics [12] via a reduction in bulk density, improved waterholding capacity and enhanced activity of soil microbes [13] (although this may increase CO 2 emission). Promoting SOC also often increases soil biodiversity and ecosystem functions that can enhance agricultural productivity by mediating nutrient cycling, soil structure formation, and crop resistance to pests and diseases [14].…”