Biometric Responses of Soybean to Different Potassium Fertilization Management Practices in Years with High and Low Precipitation

Abstract

Brazilian soybean producers commonly apply maintenance potassium (K) fertilization during cultivation to restore the K taken up by plants; however, this measure can modify the morphophysiological plant characteristics, since the functions of K are closely related with plant growth and development. This study assessed the morphological changes in soybean plants in response to K rates, sowing fertilization, and the application periods of K fertilization in a Latossolo Vermelho eutroférrico (Oxisol) under a no-tillage system, located in the municipality of Floresta, Paraná. A randomized block design was used in the experiment with four replications in a fully crossed factorial design (5 × 2 × 2). The experiment was carried out in two growing seasons (2015/2016 and 2016/2017), with a total of 80 experimental units. The rates corresponded to the first factor (0, 40, 80, 120, and 160 kg ha -1 of K). The application periods (pre-sowing and post-sowing) were the second factor, and sowing fertilization (0 and 30 kg ha -1 of K) the third. The following variables were measured: shoot dry weight, leaf dry weight, stem dry weight, leaf area, specific leaf area, leaf area ratio, and leaf area index, and these biometric parameters were correlated with soybean yield. The results showed that plants well-supplied with K exploited the environment better and this may be reversed for higher yields since there were correlations between grain yield and the biometric parameters. At lower water availability, the biometric changes were more evident.

Quality of Soybean Seeds Cultivated on Different Potassium Fertilization Management

“…Batistella Filho (2012) applying K rates cited that water unbalance could negatively influence, especially when it occurs near the harvest. In the 2017/18 growing season there were no differences for the seed mass, and the average obtained was 140.6 g. One of the possible causes may have been the lower water availability in this growing season, since some authors indicated that the plant responses to available K are clearer in adverse conditions mainly in lower water availability (Sangakkara et al, 2001;Wang et al, 2013;Zörb et al, 2014;Esper Neto et al, 2018).…”

“…and Diaporthe phaseolorum f. sp. meridionalis (Basseto et al, 2007), low water availability (Esper Neto et al, 2018) and lodging.…”

Hyperspectral Data for Early Identification and Classification of Potassium Deficiency in Soybean Plants (Glycine max (L.) Merrill)

“…Among the main abiotic factors that seriously compromise grain yield, nutritional management stands out due to the inherent low fertility of tropical soils, their high degree of weathering, and the frequent use of fertilizers at a low concentration. These challenges make nutritional management a crucial aspect of maintaining productivity [9][10][11]. The experimental site is cultivated under a no-tillage planting system, with a soybean/corn or soybean/wheat succession, with mechanized planting, and without an irrigation system.…”

Identification of Modern High-Yield Soybean Genotypes for Potassium-Use Efficiency in Sandy Soil of the Brazilian Cerrado

“…Therefore, the low fertility of Cerrado soils is the main cause of the gap between the low crop-grain yield and their productive potential, and the low K availability represents one of the most limiting factors for soybean development and productivity [6][7][8]. This low availability of K is even more limiting in sandy, sandy loam, and sandy clay loam soils, which are predominant in the Cerrado region, due to the high susceptibility of these soils to K losses by leaching [9,10].…”

“…The ability of the root system to acquire large amounts of K from the soil and translocate this nutrient to the shoots of plants plays a key role in improving the K-use efficiency of soybean genotypes [19]. Therefore, the use of soybean genotypes with a vigorous root system capable of extracting large amounts of exchangeable K from the soil, or roots with a greater capacity to solubilize non-exchangeable K from the soil through the exudation of organic acids, is fundamental for the sustainability of Brazilian soybean production systems [6,13,20]. This fact has been even more relevant in recent years, because farmers use new soybean genotypes with greater productive potential each growing season, increasing the requirement and demand for soil K in Brazilian soybean fields [13].…”