The phosphorus (P) rates recommended for corrective fertilization-P of soils from southern Brazil may be insufficient to reach the critical level for optimal plant growth. This study aimed to quantify the fertilizer-P rates for total correction fertilization with varying soil buffering capacity in the states of Rio Grande do Sul (RS) and Santa Catarina (SC). Soil samples from 0.00-0.10 and 0.10-0.20 m layers were collected from 41 locations distributed in both states. Twelve P rates were applied to each [...] ABSTRACT The phosphorus (P) rates recommended for corrective fertilization-P of soils from southern Brazil may be insufficient to reach the critical level for optimal plant growth. This study aimed to quantify the fertilizer-P rates for total correction fertilization with varying soil buffering capacity in the states of Rio Grande do Sul (RS) and Santa Catarina (SC). Soil samples from 0.00-0.10 and 0.10-0.20 m layers were collected from 41 locations distributed in both states. Twelve P rates were applied to each

The improvement of the chemical conditions of the soil in the subsurface is indicated as an alternative to increasing soybean yields because it is related to greater efficiency of water and nutrient use, such as phosphorus (P). The study aimed to evaluate the soil chemical changes and the soybean yield due to the application of P and gypsum. For this, a field experiment was conducted between 2017 and 2020 under a Humic Cambisol in Southern Brazil. The treatments were composed of four corrective rates of P₂O₅ (0, 50, 100, and 200 kg ha⁻¹) associated or not with agricultural gypsum (0 and 1400 kg ha⁻¹). In the first year of evaluation, there was an increase in soybean yield with gypsum, and rates of P. In the absence of P correction, root length density was higher in the 20–30 cm layer. There was a linear increase in P available in the topsoil (0–10 cm) as a function of the nutrient rate. With gypsum application, there was an increase in calcium (Ca) and reduction of magnesium (Mg) in the 0–10 cm layer, besides the increase of sulfate (S-SO₄^2-) in all layers. The application of agricultural gypsum promotes chemical changes in the soil at depths of up to 40 cm and gains in soybean yield, even without altering the efficiency of P use by plants.

Lime applications are used in acid soils to correct pH and eliminate Al ³⁺ toxicity in crops. The lime rates are determined based on the estimated soil potential acidity (H+Al), using soil incubations with calcium carbonate (CaCO ₃ ) for 180 days, being a time-consuming and laborious process. An alternative method with calcium hydroxide [Ca(OH) ₂ ] for 96 h incubation may efficiently estimate H+Al, but it needs further studies. Also, soils from specific regions in southern Brazil have high organic matter (SOM) contents (>5 %), medium clay contents (20-40 %), and are stony, lacking research to improve liming recommendations. The study aimed to determine potential acidity and adjust lime rates for acidity correction in medium-textured soils with high SOM and stoniness in the Serra Gaúcha region (RS), Brazil, and to test the efficiency of the short incubation alternative method. For this purpose, 20 native forest soils were sampled in the 0.00-0.20 m layer. Samples were dried, sieved, and subjected to short and long incubations. The H+Al values obtained through the incubations were compared with the Manual de calagem e adubação para os Estados do Rio Grande do Sul e de Santa Catarina (CQFS-RS/SC, 2016) equation. The H+Al values estimated by CQFS-RS/SC were lower than those determined by the long incubation, indicating lime rates ranging from 2.0 to 5.1 Mg ha ^-1 lower than in the long incubation. The short incubation showed a positive correlation (0.93***) with the long incubation. The potential acidity for soil water pH 6.5 can be obtained by long [H+Al (cmol _c dm ^-3 ) = 1354.9e ^-0.855TSM ] and short [H+Al (cmol _c dm ^-3 ) = 3763.8e ^-1.086TSM ] incubations, in which TSM is the Tampão Santa Maria index. On average, 34 % of the soil volume was composed of rock fragments (>2 mm). We recommend adjusting the limestone rates for soils with stoniness, considering only the percentage of soil in the diagnostic layer (SDL%).

Soils with low potassium (K) availability require corrective fertilization for grain crops. The recommended rate to increase K availability up to the critical level depends on the soil K buffering capacity (KBC). This study aimed to quantify the KBC and recalculate the rates necessary to reach the K critical level in 23 soils from Southern Brazil. Soil samples were incubated with six K rates, that were thus grouped according to CECpH7.0: below 7.5 cmolc dm-3 (0, 30, 60, 90, [...] ABSTRACT Soils with low potassium (K) availability require corrective fertilization for grain crops. The recommended rate to increase K availability up to the critical level depends on the soil K buffering capacity (KBC). This study aimed to quantify the KBC and recalculate the rates necessary to reach the K critical level in 23 soils from Southern Brazil. Soil samples were incubated with six K rates, that were thus grouped according to CECpH7.0: below 7.5 cmolc dm-3 (0, 30, 60, 90,

Phosphate fertilizers are applied to the soil surface, especially in vineyards in production in subtropical regions. Nowadays, phosphorus (P) is not incorporated into the soil to avoid mechanical damage to the root system in orchards. However, over the years, successive surface P applications can increase the P content only in the topsoil, maintaining low P levels in the subsurface, which can reduce its use by grapevines. For this reason, there is a need to propose strategies to increase the P content in the soil profile of established orchards. The study aimed to evaluate the effect of management strategies to (i) increase the P content in the soil profile; (ii) enhance the grape production; and (iii) maintain the grape must composition. An experiment on the ‘Pinot Noir’ grape in full production was carried out over three crop seasons. The treatments were without P application (C), P on the soil surface without incorporation (SP), P incorporated at 20 cm (IP20), P incorporated at 40 cm (IP40), and twice the P dose incorporated at 40 cm (2IP40). The P concentration in leaves at flowering and veraison, P content in the soil, grape production and its components, and chemical parameters of the grape must (total soluble solids, total polyphenols, total titratable acidity, total anthocyanins, and pH) were evaluated. The P concentration in leaves did not differ among the P application modes. The application of P associated with soil mobilization, especially at 20 cm depth, increased grape production. The P application modes did not affect the values of the chemical parameters of the grape must except for the total anthocyanins, which had the highest values when the vines were subjected to 2IP40. Finally, the P application and incorporation into the soil profile was an efficient strategy for increasing the grape production in full production vineyards.