Leandro Michalovicz

Soil fertility, nutrition and yield of maize and barley with gypsum application on soil surface in no-till

Annual crop yield and nutrition have shown differentiated responses to modifications in soil chemical properties brought about by gypsum application. The aim of this study was to evaluate the effect of gypsum application rates on the chemical properties of a Latossolo Bruno (Clayey Oxisol), as well as on the nutrition and yield of a maize-barley succession under no-till. The experiment was set up in November 2009 in Guarapuava, Parana, Brazil, applying gypsum rates of 0.0, 1.5, 3.0, 4.5, and 6.0 Mg ha-1 to the soil surface upon sowing maize, with crop succession of barley. Gypsum application decreased the levels of Al3+ and Mg2+ in the 0.0-0.1 m layer and increased soil pH in the layers from 0.2-0.6 m depth. Gypsum application has increased the levels of Ca2+ in all soil layers up to 0.6 m, and the levels of S-SO42- up to 0.8 m. In both crops, the leaf concentrations of Ca and S were increased while Mg concentrations have decreased as a function of gypsum rates. There was also an effect of gypsum rates on grain yield, with a quadratic response of maize and a linear increase for barley. Yield increases were up to 11 and 12 % in relation to control for the maximum technical efficiency (MTE) rates of 3.8 and 6.0 Mg ha-1 of gypsum, respectively. Gypsum application improved soil fertility in the profile, especially in the subsurface, as well as plant nutrition, increasing the yields of maize and barley.

Atributos químicos do solo associados à produtividade do trigo em um talhão com diferentes potenciais produtivos

Different yield potentials between plots and within them have been verified in areas managed under no-till (NT). Precision farming (PF) techniques can help in identifying these distinct areas, but for efficient soil fertility management in areas under long-term NT, there must be representative sampling. The aim of this study was to evaluate the influence of soil chemical properties on wheat yield in accordance with the sampling layer or depth in an area under long-term NT using zones of a plot with different yield potentials. The study was carried out at the Reserva do Iguacu (Iguacu Conservation Area), Parana, Brazil, in an area under NT for 25 years and with adoption of PF techniques for five years. Using data from yield maps of previous crops, two zones with distinct yield potentials were identified, named Z1 (higher yields) and Z2 (lower yields), in which sample grids with 16 units (50 × 50 m) were established. Wheat yield was estimated in three points per sampling unit, taking soil samples in the 0.0-0.1 and 0.1-0.2 m depths at the same points. Wheat yield was 22 % higher in Z1 as compared to Z2, in agreement with the yield maps from previous crops. Soil organic carbon contents (Corg) were higher in Z1 for both soil layers. In the 0.1-0.2 m layer, the aluminum saturation (m %) and the Al3+ contents were significantly higher in Z2. In this same layer, Z1 showed higher values of pH and base saturation (V %) and higher levels of Ca2+, Mg2+ and K+. There was positive correlation between wheat yield and Corg content in both soil layers, and considering only the 0.1-0.2 m layer, correlation was positive with pH, V % and Ca2+, Mg2+ and K+ contents, and negative with Al3+. The differences in soil fertility between Z1 and Z2 were mainly in the 0.1-0.2 m layer and were associated with the difference in wheat yield, indicating that the presence of this stratum is important for soil sampling in long-term NT areas aiming to correctly represent the status of soil fertility.

Flue gas desulfurization gypsum as a chemical amendment to reduce the concentrations of phosphorus and suspended solids in liquid manure

Purpose Animal liquid manure contains large amounts of phosphorus (P), which is susceptible to runoff losses when manure is surface-applied on farms as a soil amendment. Even very small quantities of P can have a large impact on waterways and lead to eutrophication. Previous studies have shown that flue gas desulfurization (FGD) gypsum, a coal combustion by-product, can reduce P losses from runoff in soils. Therefore, the authors hypothesize that FGD gypsum could reduce nutrients in liquid manure prior to field applications. The purpose of this paper is to evaluate the effect of FGD gypsum to reduce P and suspended solids (SS) concentrations in liquid manure, also determining its proper rate(s) and minimum time of reaction. Design/methodology/approach The experimental design was completely randomized with three replicates. Each plot was constituted by a polyvinyl chloride (PVC) column (1 m height and 0.15 m diameter). Dairy liquid manure and FGD gypsum rates (0, 0.62, 1.25 and 2.5 mgl−1) were added to the PVC columns and manually shaken for two minutes. Sampling was performed at 0.35, 0.65 and 0.95 m depths after 0 (immediately after shaking), 4, 8, 16 and 24 hours. Amount of phosphorus was determined by a colorimetric method and solids concentration by mass difference. Findings FGD gypsum reduced P concentrations in the liquid manure after four hours of reaction. The most effective rate was 0.62 mgl−1at a 0.35 m depth. FGD gypsum increased SS concentrations in depth in all treatments. Originality/value There are growing concerns regarding the fate of nutrients, especially phosphorus, from land application of animal waste. The results indicated that treating liquid manure in the settling tanks with FGD gypsum before field application can be particularly useful on farms where surface-manure is applied, reducing potential losses of P following manure applications, and consequently the eutrophication risk to waterways.

Soil chemical attributes, nutrient uptake and yield of no-till crops as affected by phosphogypsum doses and parceling in southern Brazil

ABSTRACT This study evaluated soil chemical attributes, leaf nutrient concentrations and grain yield of corn (Zea mays), barley (Hordeum vulgare), common bean (Phaseolus vulgaris) and wheat (Triticum aestivum) as affected by phosphogypsum (PG) rates and split application to a Typic Hapludox under no-till from Southern Brazil. A Randomized complete block design was used, with factorial treatment structure (5 x 2) consisting of increasing PG rates (0, 3, 6, 9 and 12 Mg ha−1) either in single or split (half dose, two consecutive years) application. PG rates have reduced concentrations of Al3+, increasing Ca2+, SO42- and pH values in soil layers up to 0.8 m. Leaf concentrations of Ca (between 28 and 42%) and S (between 6% and to 50%) increased in all crops, while leaf levels of Mg decreased on corn (−16%), bean (−22%) and wheat (−14%) by PG rates. Compared to the control, PG rates between 4.0 and 6.1 Mg ha−1 promoted increases of 11%, 10% and 10% on corn, barley and wheat yields, respectively. There was no effect of PG on common bean’s yield. Phosphogypsum was effective for improving soil fertility, plant nutrition and crop yields. Applying the PG annually at one-half rate gave best overall results.

Wheat yield and physical properties of a brown latosol under no-tillage in south-central Paraná

Soil management influences the chemical and physical properties of soil. Chemical conditions have been thoroughly studied, while the role of soil physical conditions regarding crop yield has been neglected. This study aimed to analyze the wheat yield and its relationship with physical properties of an Oxisol under no-tillage (NT). The study was carried out between 2010 and 2011, in Reserva do Iguacu, State of Parana, Brazil, on the Campo Bonito farm, after 25 years of NT management. Based on harvest maps of barley (2006), wheat (2007) and maize (2009) of a plot (150 ha), zones with higher and lower yield potential (Z1 and Z2, respectively) were identified. Sampling grids with 16 units (50 x 50 m) and three sampling points per unit were established. The wheat grain yield (GY) and water infiltration capacity (WIC) were evaluated in 2010. Soil samples with disturbed and undisturbed structure were collected from the 0.00-0.10 and 0.10-0.20 m layers. The former were used to determine soil organic carbon (Corg) levels and the latter to determine soil bulk density (BD), total porosity (TP), macroporosity (Mac), and microporosity (Mic). Soil penetration resistance (PR) and water content (SWC) were also evaluated. The wheat GY of the whole plot was close to the regional average and the yield between the zones differed significantly, i.e. 22 % higher in Z1 than in Z2. No significant variation in Mic was observed between zones, but Z1 had higher Corg levels, SWC, TP and Mac and lower BD than Z2 in both soil layers, as well as a lower PR than Z2 in the 0.00-0.10 m layer. Therefore, soil physical conditions were more restrictive in Z2, in agreement with wheat yield and zone yield potential defined a priori, based on the harvest maps. Soil WIC in Z1 was significantly higher (30 %) than in Z2, in agreement with the results of TP and Mac which were also higher in Z1 in both soil layers. The correlation analysis of data of the two layers showed a positive relationship between wheat GY and the soil properties TP, SWC and WIC.