Long‐term tillage effects on the distribution of phosphorus fractions of loess soils in Germany

Abstract

Different tillage systems may affect P dynamics in soils due to differently distributed plant residues, different aggregate dynamics and erosion losses, but quantitative data are scarce. Objectives were to investigate the effect of tillage on the availability of P in a long-term field trial on loess soils (Phaeozems and Luvisols) initiated from 1990 to 1997. Four research sites in E and S Germany were established with a crop rotation consisting of two times winter wheat followed by sugar beet. The treatments were no-till (NT) without cultivation, except for seedbed preparation to a depth of 5 cm before sugar beet was sown and conventional tillage (CT) with mouldboard plowing down to 25-30 cm. Soil P was divided into different pools by a sequential extraction method, and total P (P t ) in the single P fractions was extracted by digesting the extracts of the fractionation to calculate the contents of organic P. The P t content (792 mg [kg soil] -1 ) in the topsoil (0-5 cm) of NT was 15% higher compared to CT, while with increasing depth the P t content decreased more under NT than under CT. This was also true for the other P fractions except for residual P. The higher P contents in the topsoil of NT presumably resulted from the shallower incorporation of harvest residues and fertilizer P compared to CT, whereas estimated soil losses and thus also P losses due to water erosion were only small for both treatments. Contents of oxalate-extractable Fe and organic C were positively related to the labile fractions of inorganic P, while there was a high correlation of the stable fractions with the clay contents and pH. Multiple regression analyses explained 50% of the variability of these P fractions. Overall, only small differences in the P fractions and availability were observed between the long-term tillage treatments.

Effects of Reduced Tillage on Crop Yield, Plant Available Nutrients and Soil Organic Matter in a 12-Year Long-Term Trial under Organic Management

“…Other authors found, on the contrary, a clear stratification of P avail in no-till systems compared to inversion tillage with the highest values in the upper 5 cm of the no-till treatments [38]. As soil disturbance was more intensive in our study compared to the no-till treatments of Piegold et al [38], such clearly pronounced stratification could not occur.…”

“…Other authors found, on the contrary, a clear stratification of P avail in no-till systems compared to inversion tillage with the highest values in the upper 5 cm of the no-till treatments [38]. As soil disturbance was more intensive in our study compared to the no-till treatments of Piegold et al [38], such clearly pronounced stratification could not occur. In addition, as the overall P status in the experimental area was high and very heterogeneous (Table 1), and as P is a rather immobile element, changes in the P status between the different tillage systems may not be visible even after 12 years of trial duration.…”

Soil Phosphorus Pools, Bioavailability and Environmental Risk in Response to the Phosphorus Supply in the Red Soil of Southern China

“…Phosphorus fixed in soil was converted into various soil Pi fractions [ 44 ]. It has been well documented that the fractions of P in soil can greatly be dependent on soil types and the rates of P fertilizer.…”

Exogenous phosphorus compounds interact with nitrogen availability to regulate dynamics of soil inorganic phosphorus fractions in a meadow steppe

“…The positive linear correlation of soil TIP concentration and P addition rates (Fig. S2) indicates that applied P was fixed mainly into inorganic forms (Chauhan et al, 1981) and converted to various soil P fractions (Piegholdt et al, 2013). Most of the applied P transformed into soil moderate-cycling IP fractions as seen from the decrease in the relative proportion of soil recalcitrant IP fractions (Fig.…”

“…The effect of combined N and P addition on ecosystem P dynamics may further depend on their relative amounts added to the soil. For instance, inorganic P solubility and availability were particularly large when P was applied with N (Ross et al, 1995), while N and P applied at higher N : P ratios increased plant P use efficiency and leaf phosphatase activity (Hogan et al, 2010). It is well known that variation in N : P input ratios can also alter plant litter N : P ratios (Vitousek et al, 2010;Güsewell, 2004;Sun et al, 2018), thereby further affecting N and P availability through litter decomposition.…”