Effects of fertilization and soil management on crop yields and carbon stabilization in soils. A review

Abstract

-The study of sustainable land use is complex and long-term experiments are required for a better understanding of the processes of carbon stabilization. Objectives were (i) to describe for four long-term experiments the effects of fertilization and soil management on crop yields and the dynamics of soil organic carbon (SOC) and total N, and (ii) to discuss the usefulness of models for a better understanding of the underlying processes. Data of soil organic carbon and total N of four long-term experiments in Germany and China which studied the effect of fertilization (Bad Lauchstädt, Darmstadt) and tillage (Göttingen, Quzhou) were evaluated and soil organic carbon fractionation was carried out. The Rothamsted Carbon Model was used for a description and prediction of soil organic carbon dynamics as affected by fertilization and tillage in Bad Lauchstädt and Quzhou. The type of fertilizer added at common rates -either mineral N or farmyard manure -affected the crop yields only slightly, with slightly lower yields after manure application compared with mineral N fertilization. For both fertilization trials, manure applications at common rates had beneficial effects on soil organic carbon stocks in the labile pool (turnover time estimated as <10 years) and to a greater extent in the intermediate pool (turnover time estimated to be in the range of 10 to 100 years). A comparison of the effects of conventional tillage, reduced tillage and no-tillage carried out in Göttingen and Quzhou indicated only small differences in crop yields. Reduced tillage in Göttingen resulted in an increased C storage in the surface soil and C was mainly located in the mineral-associated organic matter fraction and in water-stable macro-aggregates (>0.25 mm). For Quzhou, no-tillage and conventional tillage had similar effects on total C stocks, with a greater spatial variability in soil organic carbon stocks in the no-tillage plots. Modeling required site-specific calibrations for the stock of inert organic matter for each of the sites, indicating that not all carbon stabilization processes are included in the model and that application of a model to a new site may also need site-specific adjustments before it can be used for predictions. After site-specific calibration, however, model predictions for the remaining treatments were generally accurate for the fertilization and tillage trials, which emphasizes the importance of temperature, moisture, soil cover and clay content on the decomposition dynamics of soil organic carbon and the significance of amounts and quality of carbon inputs in the soil for maintaining or increasing soil organic carbon stocks in arable soils.soil organic matter / C dynamics / Rothamsted carbon model / tillage / fertilization / soil organic carbon (SOC)

Sequestering carbon and increasing productivity by conservation agriculture

“…In contrast to the positive trends described above, review of literature on depth-distribution and total profile in relation to tillage methods indicates four distinct patterns: (1) no significant differences in SOC profile SOC pool among tillage treatments (Ludwig et al 2011); (2) more SOC under PT than NT when assessed to 1 m (3 ft) depth or more (Li et al 2007); (3) increase of SOC in the surface but decrease below the plow layer, indicating redistribution of the SOC pool because the cumulative totals are similar (Angers et al 1997;Diaz-Zorita and Grove 2000;Doran et al 1998;Xu et al 2007); and (4) decrease in the SOC pool in both PT and CA systems as in landscapes prone to severe erosion (Olson et al 2013). Declines in the SOC pool under NT are related to lower input of biomass C into the system, either because of low productivity or harvesting of residues (Kim et al 2009).…”

Increase in soil organic carbon by agricultural intensification in northern China

“…A major factor lies in the concentration of the principal parameter (i.e., SOM) which was significantly lower in cropland soils of northern China than those of the US Corn Belt (9 vs. 25 g kg −1 , Ludwig et al, 2011) or countries of western Europe, because large areas of farmlands in northern China were affected by saline-alkaline processes prior to the 1970s. The initial low crop productivity in the temperate region where N fertilization rate was low resulted in higher SOC level in northern China with increasing biomass input achieved by higher input of N. Similar trends have been reported by other studies from around the world Alvarez, 2005).…”

Acute toxicity of experimental fertilizers made of blood meal, spent coffee ground and biomass ash

“…Moreover, when applied in combination, mineral and organic fertilization has a beneficial effect allowing to achieve high yield of crops. The investigated granulated fertilizers demonstrate such feature [LUDWIG et al 2011]. In addition, the tested fertilizers can be produced in relatively short time as no composting process is required, which is an unquestionable advantage of the proposed solution, and the use of wet SCG enables the production of fertilizers, which does not depend on the season.…”