Title : Amorphous silica increases grain yield of maize grown in sandy soil in the Brazilian Cerrado
Abstract:
Maize (zea mays l.) production in sandy soils of the Brazilian Cerrado is constrained by high temperatures, high solar radiation, semiarid conditions, and intense evaporative demand, which can reduce crop performance in grain-producing areas. Silicon (Si), although not classified as an essential plant nutrient, may help crops tolerate biotic and abiotic stresses under restrictive soil and climatic conditions. This study evaluated the effects of application rates and split application of an amorphous silica fertilizer (ASF) on grain yield, yield components, and leaf Si and nutrient concentrations in maize grown in a sandy soil of the Brazilian Cerrado. A field experiment was conducted from January to June 2022 at Fazenda América – agro fritzen, Santa Filomena, Piauí, Brazil, using the maize hybrid pioneer 30F53 at 65,000 plants ha-¹. The experiment was arranged in a randomized complete block design. Treatments consisted of 0, 100, 200, 300, and 600 kg ha-¹ of ASF applied to the soil, plus split applications of 200 kg ha-¹ as 100 + 100 kg ha-¹ and 600 kg ha-¹ as 300 + 300 kg ha-¹. The fertilizer was agrisilicaTM, produced from natural diatomaceous earth of melosira granulata, containing 26% total Si, 2% calcium, 1% magnesium, and 1% iron. At 66 days after sowing (DAS), at the pre-flowering stage, 10 plants were collected from the central row of each plot to determine leaf concentrations of N, P, K, Si, Fe, Mn, Cu, and Zn. At 128 DAS, 10 ears were collected per experimental unit to determine ear length, ear diameter, number of kernel rows per ear, 1000-grain weight, total grain weight, and grain yield, with grain moisture corrected to 13%. Data were analyzed by ANOVA, linear or nonlinear regression models, and Tukey’s test at the 5% probability level. Amorphous silica fertilizer increased maize grain yield, with a positive response up to 300 kg ha-¹ of ASF, equivalent to 78 kg ha-¹ of Si, and a yield gain of up to 30% relative to the control. The 600 kg ha-¹ rate did not further increase grain yield, regardless of single or split application. The 10-ear weight followed the grain yield response, whereas 1000-grain weight was not significantly affected. Split application did not improve grain yield or yield components. Leaf Si tended to increase from 2.87 ± 1.25 g kg-¹ in the control to 5.00 ± 0.67 g kg-¹ at 600 kg ha-¹, but this response was not statistically significant. Macronutrient and micronutrient concentrations showed limited variation across treatments, indicating that yield gains were not directly explained by marked changes in leaf mineral nutrition. Under the conditions evaluated, a single application of 300 kg ha-¹ of ASF was the most suitable rate to increase maize grain yield in sandy soil of the Brazilian Cerrado.
Keywords: Amorphous silica; Brazilian Cerrado; maize; nutrient accumulation; yield parameters.
