Different limestone particle sizes for soil acidity correction, Ca and Mg supply and corn yield

The aim of this study was to evaluate the soil acidity correction and the grain yield responses for the lime application in different granulometric particles. The limestone particle sizes incorporated into the distroferric red Oxisol were: 0.20 mm to 0.30 mm; 0.30 mm to 0.56 mm; 0.56 mm to 0.82 mm and 0.82 mm to 2.00 mm, at doses of 1.3 t ha-1; 2.6 t ha-1; 3.9 t ha-1 and 6.6 t ha-1 respectively, and a control respectively, and a control (no lime incorporation in the soil). The soil chemical characteristics pH, H+Al3+, Al3+, Ca2+ e Mg2+ were evaluated at 6 months and 18 months after the lime application. The corn yields were evaluated during the 2008/2009 and 2009/2010 crop years. Higher limestone contents and lower particle size resulted in the same effect on soil acidity correction, reducing Al3+ and increasing Ca2+ and Mg2+ in the soil when the 0.30 mm limestone was incorporated, with residual effect at 18 months. Highest corn yield was obtained when the 0.82 mm to 2.00 mm particle size was incorporated in the first crop year, when compared to the lowest limestone particle size used.The aim of this study was to evaluate the soil acidity correction and the grain yield responses for the lime application in different granulometric particles. The limestone particle sizes incorporated into the distroferric red Oxisol were: 0.20 mm to 0.30 mm; 0.30 mm to 0.56 mm; 0.56 mm to 0.82 mm and 0.82 mm to 2.00 mm, at doses of 1.3 t ha-1; 2.6 t ha-1; 3.9 t ha-1 and 6.6 t ha-1 respectively, and a control respectively, and a control (no lime incorporation in the soil). The soil chemical characteristics pH, H+Al3+, Al3+, Ca2+ e Mg2+ were evaluated at 6 months and 18 months after the lime application. The corn yields were evaluated during the 2008/2009 and 2009/2010 crop years. Higher limestone contents and lower particle size resulted in the same effect on soil acidity correction, reducing Al3+ and increasing Ca2+ and Mg2+ in the soil when the 0.30 mm limestone was incorporated, with residual effect at 18 months. Highest corn yield was obtained when the 0.82 mm to 2.00 mm particle size was incorporated in the first crop year, when compared to the lowest limestone particle size used

Phytotechnical parameters and yield of watermelon plants under different irrigation and nitrogen levels

Water and nitrogen availability are fundamental for obtaining a high yield of the watermelon plant. However, the appropriate levels of irrigation and nitrogen to be applied according to specific cultivation conditions should be previously determined. The objective of the present study was to evaluate the effects of irrigation and nitrogen levels in fertigation on the phytotechnical parameters and yield of the Top Gun hybrid watermelon plant. The experiment was conducted at São Luiz Ranch, in Bom Jesus (PI), from August 4 to October 15, 2015. The blocks in strips experimental design was used with four repetitions, and the treatments consisted of five irrigation depths (114.17, 156.86, 221.16, 268.87, and 317.09 mm) and five doses of nitrogen in fertigation (0, 50, 100, 150, and 200 kg ha-1). The growth rate of the main and primary branches, leaf area, specific leaf area, stem diameter, dry mass of the aerial part, number of fruits, and commercial production per plant were evaluated. Both hydric and nutritional stress caused decreased growth rates, leaf areas, and specific leaf areas, and the highest growth expressions were found with the combination of a 317.09 mm irrigation depth and 200 kg ha-1 nitrogen. The irrigation depths did not influence the diameter of the stem nor the accumulation of dry mass. Nitrogen doses did not influence the number of fruits and production. The 247.95 mm irrigation depth promoted the highest commercial fruit production of the watermelon plant.Water and nitrogen availability are fundamental for obtaining a high yield of the watermelon plant. However, the appropriate levels of irrigation and nitrogen to be applied according to specific cultivation conditions should be previously determined. The objective of the present study was to evaluate the effects of irrigation and nitrogen levels in fertigation on the phytotechnical parameters and yield of the Top Gun hybrid watermelon plant. The experiment was conducted at São Luiz Ranch, in Bom Jesus (PI), from August 4 to October 15, 2015. The blocks in strips experimental design was used with four repetitions, and the treatments consisted of five irrigation depths (114.17, 156.86, 221.16, 268.87, and 317.09 mm) and five doses of nitrogen in fertigation (0, 50, 100, 150, and 200 kg ha-1). The growth rate of the main and primary branches, leaf area, specific leaf area, stem diameter, dry mass of the aerial part, number of fruits, and commercial production per plant were evaluated. Both hydric and nutritional stress caused decreased growth rates, leaf areas, and specific leaf areas, and the highest growth expressions were found with the combination of a 317.09 mm irrigation depth and 200 kg ha-1 nitrogen. The irrigation depths did not influence the diameter of the stem nor the accumulation of dry mass. Nitrogen doses did not influence the number of fruits and production. The 247.95 mm irrigation depth promoted the highest commercial fruit production of the watermelon plant