Copper Availability in an Acidic and Limed Zeolite-Amended Soil

In acidic soils, copper (Cu) availability may be high because of Cu impurities of various agricultural additives. This research was aimed at assessing liming and zeolite application as availability reduction methods. In a soil with pH 3.8, lime was added at 6.6 Mg ha(-1), and zeolite was added at 3.3% and 10% in a 100-day pot trial with ryegrass. On day 50 zeolite was more effective in reducing Cu availability [as expressed by diethylenetriaminepentaacetic acid (DTPA) soil extractions and plant concentration measurements] than liming. On day 100, Cu levels were further reduced in both treatments, indicating the effectiveness of both zeolite and liming over the study period to retain Cu. Zeolite alone reduced Cu concentration in plants to 26%, liming alone reduced it by 21%, and the combination of the two reduced it by 43%. The orders in the DTPA extractions and the soil-to-plant Cu transfer coefficients were similar

Nitrogen and phosphorus availability to ryegrass in an acidic and limed zeolite-amended soil

Nitrogen and P fertilization increases crop yields, especially in acidic soils, but its effect may be minimized by various N loss and P retention processes. Zeolite may enhance N and P fertilizer efficiency. The aim of this study was to compare N and P availability and recovery efficiencies to ryegrass, as well as soil available nitrogen, in acidic and limed zeolite-added soils. In a pot experiment with ryegrass we added escalating zeolite quantities to an acidic and limed soil and we measured soil NH4-N dynamics and N and P in plant. Added zeolite protected NH4-N by releasing it more slowly when compared to the no-zeolite treatments. Recovery efficiency (uptake compared to added nutrient) increased with zeolite from 11.7% (no-zeolite) to 30% (zeolite treatment) for N and from 1.52% to 4.02% for P. Even under the unfavourable conditions of an acidic soil, N and P recovery efficiencies were greatly improved due to zeolite. This was induced by the slow release of ammonium cations, which kept the available NH4-N unchanged and due to the protection of the available P from being retained onto soil colloids