Soil Organic-Matter in Water-Stable Aggregates Under Different Soil-Management Practices

Abstract An experiment of different management practices in a commercial vineyard, which was established in 2006 in the locality of Nitra-Dražovce, Slovakia on Rendzic Leptosol, was used to evaluate the dynamics of soil organic-matter parameters during the years 2008–2015. The following treatments were established: 1. G (grass without fertilisation as control), 2. T (tillage), 3. T+FYM (tillage + farmyard manure), 4. G+NPK3 (grass + 3rd intensity of fertilisation for vineyards: it means 125 kg/ha N, 50 kg/ha P, 185 kg/ha K), and 5. G+NPK1 (grass + 1st intensity of fertilisation for vineyards: it means 100 kg/ha N, 30 kg/ha P, 120 kg/ha K). The results showed that the soil-management practices in the vineyard significantly influenced the soil organic carbon in water-stable aggregates (SOC in WSA). The content of SOC in WSAma increased on average in the following order: T < G < G+NPK1 < G+NPK3 < T+FYM. Intensive soil cultivation in the T treatment resulted in a statistically significant build-up of SOC in WSAma at an average rate of 1.33, 1.18, 0.97, 1.22 and 0.76 g/kg/y across the size fractions > 5 mm, 5‒3 mm, 2–1 mm, 1–0.5 mm and 0.5–0.25 mm, respectively. The content of non-labile carbon reflected the contents of SOC in WSA. The highest labile carbon (CL) in WSAma, as compared to others, was found in T+FYM. Overall, application of higher NPK doses resulted in higher content of CL in WSAma compared with the lower applications of NPK. On the other hand, lower applications of NPK to soil increased the content of CL in WSAmi, as compared to G+NPK3.