Silicon fertilization and soil water tensions on rice development and yield

ABSTRACT The cultivation of upland rice (Oryza sativa) in Brazil occurs mainly in the Cerrado, a region with adverse weather conditions. The use of silicon in its cultivation becomes important, since this nutrient provides higher rigidity, lower transpiration and higher resistance to dry spells in rice plants. The objective of the present study was to evaluate the effect of silicon fertilization and soil water tensions on upland rice development and yield in a Cerrado Oxisol. A 5 x 5 fractionated factorial with five soil water tensions (0, 15, 30, 45 and 60 kPa) and five silicon doses (0, 120, 240, 480 and 960 mg dm-3) was used, which were distributed in a randomized block design, with four replicates. Plant height, number of tillers, number of panicles, number of grains per panicle, numbers of full and empty grains and percentage of empty grains were evaluated. Silicon fertilization promotes increased tillering in rice plants at the dose of 960 mg dm-3. The numbers of tillers and panicles decreased with the application of silicon up to the doses of 460 and 490 mg dm-3, respectively. The increase in soil water tensions reduced plant height and the number of full grains, and increased the percentage of empty grains of upland rice.

摘要 巴西旱稻（Oryza sativa）的种植主要集中于气候条件恶劣的塞拉多（Cerrado）区域。在旱稻栽培过程中施用硅肥的意义愈发重要，该营养元素可提升稻株刚性、降低蒸腾速率，并增强其对干旱时段的抗性。本研究旨在探究塞拉多地区氧化土（Oxisol）中，硅肥施用与土壤水势对旱稻生长发育及产量的影响。实验采用5×5部分因子析因设计，设置5个土壤水势梯度（0、15、30、45、60 kPa）与5个硅肥施用量梯度（0、120、240、480、960 mg·dm⁻³），并以随机区组设计进行排布，设置4次重复。本试验测定的指标包括株高、分蘖数、穗数、每穗实粒数、饱粒数、空秕粒数以及空秕粒率。当硅肥施用量为960 mg·dm⁻³时可促进旱稻分蘖。分蘖数与穗数分别在施硅量达到460 mg·dm⁻³和490 mg·dm⁻³时，随施硅量增加呈下降趋势。土壤水势升高会降低旱稻株高与饱粒数，并提升其空秕粒率。