The responses of soil organic carbon and total nitrogen to chemical nitrogen fertilizers reduction base on a meta-analysis

Abstract

Soil organic carbon (SOC), total nitrogen (TN), and their ratio (C:N) play important roles in preserving soil fertility, and their values are closely related to fertilizer use. However, the overall trend and magnitude of changes in SOC, TN and C:N in response to chemical nitrogen fertilizers reduction remain inconclusive. Here, the meta-analysis conducted comparisons at 48 sites covering various cropping system, soil type, and climatic regions of China to investigate the responses of SOC, TN and C:N to chemical nitrogen fertilizers reduction. The results showed that chemical nitrogen fertilizers reduction decreased SOC by 2.76 ± 0.3% and TN by 4.19 ± 0.8%, and increased the C:N by 6.11 ± 0.9% across all the database. Specifically, the reduction of chemical nitrogen without adding organic nitrogen fertilizers would reduce SOC and TN by 3.83% and 11.46% respectively, while they increased SOC and TN by 4.92% and 8.33% respectively with organic fertilizers supplement, suggesting that organic fertilizers could cover the loss of SOC, TN induced by chemical nitrogen fertilizers reduction. Medium magnitude (20–30%) of chemical nitrogen fertilizers reduction enhanced SOC by 6.9%, while high magnitude (≧30%) and total (100%) of chemical nitrogen fertilizers reduction significantly decreased SOC by 3.10% and 7.26% respectively. Moreover, SOC showed a negative response to nitrogen fertilizers reduction at short-term duration (1–2 years), while the results converted under medium-long-termThis system analysis fills the gap on the effects of fertilizer reduction on soil organic carbon and nitrogen at the national scale, and provides technical foundation for the action of reducing fertilizer application while increase efficiency.

Soil conditioner improves soil properties, regulates microbial communities, and increases yield and quality of Uncaria rhynchophylla

“…The most significant effect was observed with lime powder, which is associated with the alkaline nature of lime powder 25 . AHN or TN levels are commonly used indicators for assessing soil N supply capacity 26 . The M2 treatment exhibited the sole increase in AHN content, with the maximum values observed for soil TN and SOM ( p < 0.05; Table 1 ).…”

Organic Carbon Stock in Mineral Soils in Cropland and Grassland in Latvia

“…Factors beyond soil texture may have played a role in SOC dynamics in our study, such as land management practices, climate and environmental conditions, vegetation type and productivity, and soil moisture regime. SOC, TN, and C/N ratio are pivotal factors in maintaining soil fertility, and their values exhibit a close association with the use of fertilizers [67]. When evaluating SOC stock based on both WRB groups and texture classes, a very strong or strong significant correlation between SOC stock and soil TN concentration was found in the majority of cases.…”

Assessment of Soil Fertility and Nutrient Management Strategies in Calcareous Soils of Khuzestan Province: A Case Study Using the Nutrient Index Value Method

“…More than 91% of soil samples exhibit low nitrogen levels, possibly due to the low SOC content in the study areas. This is because soil nitrogen is directly linked to SOC (Li et al 2022). The mean nitrogen content in the study areas is 0.05%.…”