Reduced tillage in temperate organic farming: Effects on soil nutrients, nutrient content and yield of barley, rye and associated weeds

Abstract

In temperate regions, reduced tillage is still not broadly accepted in organic farming although the guidelines often recommend the reduction of tillage intensity. During the years 5–7 of a long-term experiment, we studied the effects of the three tillage systems moldboard plowing (MP, soil inversion to 30 cm depth), two-layer plowing (TP, inversion to 15 cm, loosening to 30 cm) and layer cultivation (LC, loosening to 30 cm) on soil nutrients, nutrient content of barley, rye and associated weeds, and yield on a clay loam soil. Crops were cultivated within a five-course crop rotation consisting of green fallow, winter wheat, field peas, winter rye and spring barley; no additional fertilizers were applied. Tillage affected only soil nitrate under barley, which decreased with decreasing tillage intensity. Soil humus, phosphorus (P) and potassium (K) were unaffected by tillage under both crops. Barley shoot nitrogen content was significantly influenced by tillage, with, across years, 38 and 83% higher values under MP than under TP or LC, respectively. Weeds in barley had a higher P and K content at LC than at MP or TP. This resulted, across years, in 73% higher barley yields in MP than in LC. The TP showed a 29% higher barley yield than the LC. Tillage methods had no effect on rye nutrient contents, rye yields or on weeds associated with rye. The significant interaction between tillage and year for rye yield suggests that weather conditions in a given year (e.g., amount of rainfall) can considerably alter the effect of reduced tillage.

Diversified Arable Cropping Systems and Management Schemes in Selected European Regions Have Positive Effects on Soil Organic Carbon Content

“…Conversely, SOC contents decreased by 10%, 6%, and 13% in the layers 10-20, 20-30, and 30-60 cm respectively. No tillage ( Figure 3b) had a significant effect (12%) in increasing SOC contents compared to CT across all depths (0-60 cm) when considering the references providing SOC content by depth ranges [39,69,[73][74][75][76][77][78][79][80]. In addition, both NT and MT systems were significantly different in comparison with CT in the 0-10 cm depth range (Figure 3c), with SOC content increases by 36 and 25% respectively.…”

“…Compared to CT, SOC content increases were significantly higher only with NT (7%) ( Figure 1a) when considering the references providing SOC content only for a single layer . Significant SOC content increases by conservation tillage management were found with crop rotation (5%, Figure 1b Results by soil depths [39,69,[73][74][75][76][77][78][79][80] showed an average SOC content increase by 28% in the 0-10 cm layer with conservation tillage management (including no tillage, minimum tillage, and rotational tillage) compared to conventional deep tillage ( Figure 3a). Conversely, SOC contents decreased by 10%, 6%, and 13% in the layers 10-20, 20-30, and 30-60 cm respectively.…”

“…The final selection included 304 comparisons from a total of 38 references . Moreover, studies providing SOC content by soil depths under tillage management were also considered, with 167 comparisons from 10 references [39,69,[73][74][75][76][77][78][79][80].…”

“…We did not calculate and compare SOC stocks, since most studies did not report measurements of bulk density, and using pedotransfer functions was not considered appropriate due to the high heterogeneity of soils, treatments, and environmental conditions. SOC content changes by soil depths [39,69,[73][74][75][76][77][78][79][80] were represented using the depth range reported in the studies and analyzed by groups, i.e., 0-10, 10-20, 20-30, and 30-60 cm.…”

Effects of Reduced Tillage on Dynamic Soil Properties and Winter Triticale Performance in Organic Farm at Wageningen, the Netherlands

“…However, successive use of CON has been reported to have negative environmental impacts, as it may cause soil degradation, soil erosion, and water and air pollution [5,6]. Furthermore, high soil nutrient contents under CON can lead to nitrate leaching thereby affecting surface and groundwater bodies [7]. To rescue the situation, conservation tillage practices that include no tillage and reduced tillage have been adopted to increase the organic matter content and aggregate stability of the topsoil [8], bulk density and penetration resistance [9].…”