Effects of Long‐Term Fertilization on Soil Carbon and Nitrogen in Chinese Mollisols

Abstract

ree eld experiments were conducted to examine the in uence of long-term (30-31 yr) e ect of fertilizer applications on soil C and N in the mollisols of Northeast China. Each experiment represented a di erent latitude range: low latitude (LatL), middle latitude (LatM) and high latitude (LatH). Four types of fertilizer applications were considered: (i) CK: unfertilized (control); (ii) NPK: balanced application of inorganic fertilizer nitrogen, phosphorus, potassium; (iii) M: application of organic manure; and (iv) NPKM: fertilizer nitrogen, phosphorus, potassium, plus organic manure. Compared with CK treatments, applications of fertilizers increased soil organic carbon (SOC), total nitrogen (TN), available nitrogen (AN), microbial biomass carbon (Cmic) and microbial biomass nitrogen (Nmic). On average compared with CK treatments, SOC in the NPK, M, and NPKM treatments increased by 2.74, 22.00, and 27.81%, respectively. us, applications of organic manure combined with inorganic fertilizers showed greater e ects on the topsoil C and N content than inorganic fertilizers. Under the same fertilizer treatments, SOC, TN, Nmic, and Cmic contents were the lowest at LatM site. Available N content decreased for a latitude sequence of LatH > LatM > LatL for CK, M, and NPKM treatments and LatM > LatH > LatL for the NPK treatments. ese results indicate that the magnitude of soil C and N among the three sites was not related to the latitude of the experiments.

Plant–microbe networks in soil are weakened by century‐long use of inorganic fertilizers

“…Consistent with the previous studies (Jiao et al ., ; Wang et al ., ,b), our results showed that changes in soil C and N contents were the main factors that affect the plant–microbe networks. From the standpoint of soil C content, soil microbes such as bacteria and fungi mainly rely on the large amounts of sugars, amino acids and organic acids deposited in the plant rhizosphere (Bais et al ., ).…”

Mitigated Greenhouse Gas Emissions in Cropping Systems by Organic Fertilizer and Tillage Management

“…The combined application of organic and inorganic fertilizers reduced C emissions compared with the sole application of organic fertilizer. This was because it improved the immobilization of active C (e.g., microbial biomass C, readily oxidizable C) [43][44][45]. Thus, the results of this study showed that CO 2 emissions under microbial fertilizers application are reduced significantly (Figure 6).…”

“…To a large extent, this was because JS promoted the decomposition of straw without nitrogen fixation. Previous studies [44,45] reported that the combined application of organic and inorganic fertilizers enhanced the activity of organic C and N and the immobilization of ammonium N. This equally explained why N 2 O emissions under ETS were lower than those under the JS treatment, as organic matter in ETS enhanced N fixation. Additionally, microbial fertilizer can also alter soil denitrification by changing the functional gene of denitrifying agents [56,57], which could limit N 2 O flux with the application of microbial fertilizer.…”

Does off-farm employment contribute to chemical fertilizer reduction? New evidence from the main rice-producing area in Jilin Province, China

“…However, for decades, predatory development and the heavy use of nutrients have led to a long-term excess of CF inputs. Agricultural surface pollution and soil consolidation problems are becoming increasingly serious, the ecological environment continues to deteriorate, the black soil layer is thinning, and the soil organic matter content is declining rapidly [76,77]. In addition, with the increasing level of urbanization, the rural population of Jilin Province has been flowing out so it has decreased from 12.9 million in 2005 to 11.23 million in 2019.…”