Model-Based Analysis of the Long-Term Effects of Fertilization Management on Cropland Soil Acidification

Abstract

Agricultural soil acidification in China is known to be caused by the over-application of nitrogen (N) fertilizers, but the long-term impacts of different fertilization practices on intensive cropland soil acidification are largely unknown. Here, we further developed the soil acidification model VSD+ for intensive agricultural systems and validated it against observed data from three long-term fertilization experiments in China. The model simulated well the changes in soil pH and base saturation over the last 20 years. The validated model was adopted to quantify the contribution of N and base cation (BC) fluxes to soil acidification. The net NO leaching and NOinput accounted for 80% of the proton production under N application, whereas one-third of acid was produced by BC uptake when N was not applied. The simulated long-term (1990-2050) effects of different fertilizations on soil acidification showed that balanced N application combined with manure application avoids reduction of both soil pH and base saturation, while application of calcium nitrate and liming increases these two soil properties. Reducing NH input and NO leaching by optimizing N management and increasing BC inputs by manure application thus already seem to be effective approaches to mitigating soil acidification in intensive cropland systems.

Drivers of spatio-temporal changes in paddy soil pH in Jiangxi Province, China from 1980 to 2010

“…63 reported the greatest effects of Nitrogen fertilizer on farmland soil acidification from long-term monitoring. In the current study, Nitrogen fertilizer application rates in Jiangxi province had a slight stronger influence on soil acidification over acid rain (determined from regression coefficients) and was consistent with other studies 4,23,29 . However, true effect of acid rain intensity can only be examined by taking the integrated data over the whole study period and was a limitation for this study.…”

“…Our result was in line with the general trend of the effect of acid rain intensity. The Nitrogen fertilizer application rate also showed a very similar effect on the soil acidification in the study area 4,10,12,15–19,23,35,49,54,57 . From a long-term fertilization experiment, Zhang 29 reported that unreasonable agricultural practices such as Nitrogen fertilizer application intensified the soil acidification process over other activities, such as burning of fossil fuels contributing acid-deposition.…”

“…Adaptation of inappropriate cropping systems and the application of large quantities of Nitrogen fertilizer lead to low fertilizer use efficiency and contributed substantially to soil acidification in China 4,10,12,14–19,23,35,49,54–57 . Jiangxi province is no different 40,54,58 .…”

“…Higher amounts of fertilizer consumption have already degraded soils and affected the environmental quality in various parts of China 10,12,14–20 , including the North China Plain 15 , black soil of North-East China 21 , the red soil area 22 , and the Taihu Lake area 14 . This may also have a direct and an indirect influence on soil acidity 10,16,23 . Additionally, the effect of acid rain in the region also contributed to the acidification 24–28 .…”

Is Biomass Accumulation in Forests an Option to Prevent Climate Change Induced Increases in Nitrate Concentrations in the North German Lowland?

“…The VSD model (Very Simple Dynamic) has proven to be suitable to describe the dynamics of the acid-base status [54,55], and C and N dynamics of forest soils, e.g., for ICP Forests Level II plots in Germany [56][57][58][59][60][61]. The VSD model was chosen in this study due to its relatively low data requirements and the limited data availability in the model regions.…”