1. Salt effect of potassium fertilizer on productivity and technological quality of sugarcane
- Author
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Fernando José Freire, Emídio Cantídio Almeida de Oliveira, Djalma Euzébio Simões Neto, Maria B. G. dos S. Freire, Anibia Vicente da Silva, Igor Tenório Marinho da Rocha, and Edivan Rodrigues de Souza
- Subjects
Soil salinity ,Potash ,Plant Science ,engineering.material ,Salinity ,Agronomy ,Productivity (ecology) ,Oxisol ,Soil water ,engineering ,Environmental science ,Fertilizer ,Sugar ,Agronomy and Crop Science - Abstract
The K is important for sugar concentration in sugarcane, but the salt effect on K fertilizer may reduce the productivity. The objective of this study was to evaluate productivity of sugarcane, to establish soil and plant K critical levels, and to determine a saline limit of the soil with maximum agronomic efficiency. The sugarcane variety RB992506 was cultivated in the field in Oxisol (Kandic) dystrophic with very sandy and low K content, mainly in subsurface. Six doses of K2O were used: 0; 25; 50; 100; 200; 250 kg ha-1. We evaluated soil and leaf K content, electrical conductivity of the saturated soil paste, productivity and technological quality of the sugarcane. The application of K promoted increase in soil and leaf K levels, increasing also both productivity and the sugar concentration. The dose of maximum agronomic efficiency was 150 kg ha-1 of K2O and production of 116 Mg ha-1. High doses of K (> 200 kg ha-1 of K2O) decreased the productivity due to elevated soil salinity by the application of K fertilizer. The critical levels of K were 0.18 cmolc dm-3 in the soil and 9.53 g kg-1 in the plant and were associated with low doses of K (< 25 kg ha-1 of K2O). The salinity limits that reduced productivity were 1.38 dS m-1 in the surface layer and 1.19 dS m-1 in the subsurface, suggesting that these critical levels and limits can be used to evaluate the fertility of sandy soils cultivated with sugarcane in tropical regions.
- Published
- 2019