Assessment of plant nutrients’ dynamics in organically and conventionally managed soils by means of different extraction methods
2017
Järvan, Malle | Vettik, Raivo | Adamson, Ando
The aim of this study was to investigate what kind changes in the soil fertility parameters occur depending on different farming methods. The field experiment was performed on sandy loam Luvisol during 2008–2014. The following treatments were carried out: organic (ORG), organic with farmyard cattle manure (ORGFYM) and conventional with farmyard cattle manure and mineral fertilizers (CONFYM). Soil samples were collected yearly in September and analyzed for P, K, Mg and Ca by the Mehlich III method. In parallel, ammonium lactate extractable P and K (AL method), and ammonium acetate extractable Mg and Ca (NH ₄OAc-method) were determined. The Pearson correlation coefficients between the analysis results achieved by the Mehlich III method and alternative methods were calculated. In all the treatments, no significant changes in soil Corg content were established over seven years. A significant (p < .05) decrease in soil pH was shown for the CONFYM treatment. Organic management without nutrients’ input does not decrease the content of P AL in the soil but considerable decrease in the soil K AL content was revealed. The application of cattle manure (60 t ha ⁻¹ for the 5-year crop rotation) in both organic and conventional treatments sustained the status of available nutrients in the soil. The Pearson correlation coefficients between Mehlich III and AL methods for P (r = 0.770 , p < .01) were lower than for K (r = 0.922 , p < .01). The highest correlation between Mehlich III and NH ₄OAc-methods was found in the case of Mg (r = 0.951 , p < .01) whereat for Ca the correlation was somewhat weaker (r = 0.841 , p < .01). It was also shown that the P Mₑₕₗᵢcₕ III/P AL quotient was inversely proportional with the Ca Mₑₕₗᵢcₕ III values.
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