Use of silicon in the growth and production of bean plants under different water conditions

Abstract

The objective of this work was to investigate the use of silicon (Si) in the growth and production of bean plants under different water conditions in the substrate. For this, common bean plants, Phaseolus vulgaris, cultivar SCS207 “Querência” from the Rio group, were grown in plastic pots containing 8 dm^-3 of substrate inside the greenhouse of the Instituto Federal Catarinense, Campus Videira. The plants grew with the substrate kept close to field capacity for 45 days after emergence (DAE), when two water levels were established, defined based on the total porosity of the soil, with values of 50 (D+) and 100% (D-) of the total volume of pores occupied by water (Field Capacity), with irrigation control carried out using the gravimetric method (daily weighing of the vessels), adding water until the mass of the vessel reached the previously determined value, considering the mass of soil and water. The application of Si doses was carried out using a manual sprayer with a capacity of 500 mL and a fan-type nozzle for application. Control plants where Si was not applied were sprayed with distilled water. The simple mineral foliar fertilizer potassium silicate (Flex Silício^®) was used in doses: 0 mL/L (Control, Si-) and 6 mL/L (Si+) of potassium silicate, applied at 45, 60 and 75 DAE . The experiment was set up in a 2×2 factorial scheme, with four replications, consisting of two water levels [100 and 50% of field capacity, that is, without water deficit (D-) and with water deficit (D+), respectively ] and two dose levels of Si [0.0 mL/L (Control, Si-) and 6mL/L (Si+), arranged in a completely randomized experimental design, in plots subdivided over time (15, 30, 45, 60, 75 and 90 DAE). Each experimental unit was composed of a plastic pot containing two plants. Growth and development assessments were carried out biweekly, until the end of the experimental period, starting after the fifteenth day of seedling emergence. In each collection, the following variables were analyzed per plant in each treatment: height, diameter of the collection, number of pods and estimated leaf area, the dry matter of leaves, branches and stem, root and total (leaf, branches and stem, and root). Production was measured through the dry mass of pods and seeds (grains) per plant, carried out at the end of the experiment. The potential productivity of the bean plant was also estimated according to the values obtained for the dry matter of the grains per plant, considering a spacing of 40 x 50 cm in one hectare (ha), which totaled 50 thousand plants/ha. The results obtained showed, in general, that the supply of Si benefited the vegetative growth and development of plants, under conditions of adequate water availability in the substrate, as can be evidenced by the significant increases found for height, stem diameter, length of the root and leaf area. The supply of Si combined with adequate water availability in the substrate (Si+D-) contributed to significant increases in the dry matter of leaves, stems and branches, roots and total, leading to greater production in grain dry matter and productivity. Si also contributed to alleviating the water deficit, improving the growth and yield of the bean plant when compared to plants where the element was not supplied.