Applications of swine residues to the soil surface in a no-tillage system (NTS) may increase the organic carbon level and improve the physical properties of the soil. This study aimed to evaluate the effect of the continuous application of pig slurry (PS) and pig litter (PL) on the total organic carbon (TOC) content and physical properties of soil under NTS in Southern Brazil. In March 2010, after 8 years of cultivation of black oats (Avena strigosa)–maize (Zea mays), soil samples were collected in the 0–5, 5–10, 10–15, and 15–20 cm layers. The treatments consisted of a control plot (without manure application), plots with PS applications equivalent to one and two times the recommended rate of nitrogen (N) for maize and black oats (PS1X and PS2X, respectively), and plots with PL equivalent to one and two times the recommended rate of N for maize and black oats (PL1X and PL2X, respectively). The TOC, soil bulk density (BD), penetration resistance (PR), total porosity (TP), macro- and microporosity, distribution of pore diameters, and indices of aggregation and aggregate stability were evaluated. Differences were found between treatments for TOC, BD, macro- and microporosity, pore diameter, aggregation, and PR. Treatment with PL favoured the production of aggregates (diameter >4 mm) and increased the rates of aggregation and aggregate stability in the 10–15 and 15–20 cm layers and macroporosity in the 0–5 and 15–20 cm layers. Application of PL2X reduced PR by 34% and 20%, respectively, in the 5–10 and 10–15 cm layers. Eight years of adding PS to successive cultivations of black oats–maize soil managed under NTS produced no changes in the physical features or the TOC of the soil, whereas the application of PL produced improvements in physical attributes of the soil and increased soil TOC.
In soils rich in organic matter (OM), such as those in the elevations of South Brazil, the mineralized N from organic matter does not always meet the N demands of grapevines, thus, N applications are necessary during vine growth. However, the optimal N rate to achieve satisfactory yield and desirable grape enological composition is not known. The study aimed to evaluate yield and must composition of grapevine subjected to N applications, in relation to temperature and rainfall. The experiment was conducted in a vineyard planted in 2003 in the city of Água Doce, located in the Midwest region of the state of Santa Catarina, southern Brazil. The cultivar 'Chardonnay' grafted on rootstock 1103 Paulsen, planted in clay, high-OM soil was trained as a spur pruned cordon system. From 2011 to 2014, the grapevines were submitted to the application of N as urea at the following rates: 0, 20, 40, 80 and 120 kg N ha -1 split at bud sprout and full bloom. Leaves, collected at flowering and veraison, were dried, milled and analyzed for total N. At harvest, the number of clusters per plant and yield were recorded. Total soluble solids, titratable acidity, pH and tartaric acid were evaluated on must. Temperature and rainfall data were collected throughout the experiment. The application of N increased N concentration in leaves but had little effect on yield and must composition. According to principal component analysis, a negative correlation between rainfall and N in must was found.
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