Variability on Yield, Nutritional Status, Soil Fertility, and Potassium-Use Efficiency by Soybean Cultivar in Acidic Soil

ABSTRACT Aiming to evaluate the effect of potassium (K) doses applied by the conventional method and fertigation in zucchini (Cucurbita pepo L.), a field experiment was conducted in Fortaleza, CE, Brazil. The statistical design was a randomized block, with four replicates, in a 4 x 2 factorial scheme, which corresponded to four doses of K (0, 75, 150 and 300 kg K2O ha-1) and two fertilization methods (conventional and fertigation). The analyzed variables were: fruit mass (FM), number of fruits (NF), fruit length (FL), fruit diameter (FD), pulp thickness (PT), soluble solids (SS), yield (Y), water use efficiency (WUE) and potassium use efficiency (KUE), besides an economic analysis using the net present value (NPV), internal rate of return (IRR) and payback period (PP). K doses influenced FM, FD, PT and Y, which increased linearly, with the highest value estimated at 36,828 kg ha-1 for the highest K dose (300 kg K2O ha-1). This dose was also responsible for the largest WUE, 92 kg ha-1 mm-1. KUE showed quadratic behavior and the dose of 174 kg K2O ha-1 led to its maximum value (87.41 kg ha-1 (kg K2O ha-1)-1). All treatments were economically viable, and the most profitable months were May, April, December and November.

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Fertilization With Nitrogen, Phosphorus and Potassium on Soil Fertility and Nutritional Status of Yellow Passion Fruit Plants

Journal of Agricultural Science ◽

10.5539/jas.v11n5p142 ◽

2019 ◽

Vol 11 (5) ◽

pp. 142

Author(s):

Rodrigo T. M. Miyake ◽

William H. S. Takata ◽

Nobuyoshi Narita ◽

José E. Creste

Keyword(s):

Nutritional Status ◽

Soil Fertility ◽

Nitrogen Fertilization ◽

Passion Fruit ◽

Triple Superphosphate ◽

Fruit Plants ◽

Phosphorus And Potassium ◽

Maximum Content ◽

Nitrogen Phosphorus ◽

Yellow Passion Fruit

The research had as objective to study the influence of the doses of nitrogen, phosphorus and potassium on soil fertility and nutritional status of yellow passion fruit plants. The experimental design was in randomized blocks in an incomplete fractioned factorial 1/2 (4 × 4 × 4), with four doses of N (150, 300, 600 and 1200 Kg-1 ha-1 yr-1 N); four doses of P2O5 (200, 400, 800 and 1600 kg-1 ha-1 yr-1) and four doses of K2O (100, 300, 500 and 700 kg-1 ha-1 yr-1). The fertilizers used were the ammonium nitrate = 32% N; triple superphosphate = 44% P2O5 and potassium chloride = 60% K2O. In the fertility of the nitrogen fertilization increased the content of phosphorus and sulfur. The doses of P2O5 increased the concentration of P in the soil. The doses of K2O influenced the increase in the content of K in the soil in the harvest 2013/2014. There was an interaction of the doses of N and K2O in the availability of K in the soil in the harvest 2012/13 with the maximum levels of K, in the doses of 200-400 kg N ha-1 and 600 to 700 kg ha-1 of K2O. In the nutritional state the yellow passion fruit plants was influenced by the doses of N for the sulfur content of the leaves. The maximum content of S leaf concentration of 3.63 g kg-1 was obtained in the dose estimated at 1120 kg ha-1 of P2O5.

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