Phytometric characteristics and chlorophyll index of “Paiaguás” grass (Urochloa brizantha) as a function of wood ash doses and soil water stress

Abstract

The objective of this study was to evaluate the phytometric characteristics and chlorophyll index of paiaguás grass (Urochloa brizantha) fertilized with wood ash doses and soil water availability. The experiment was carried out in a randomized complete block in a 5x5 fractional factorial scheme (five doses of wood ash: 0, 8, 16, 24 and 32 g dm-3, and five soil water stresses: 4, 8, 16, 32 and 64 kPa), with four replicates. The experimental design was based on the modified central compound, in which 13 combinations of wood ash doses and soil water availability were studied. Each experimental unit consisted of a pot containing 8.7 dm3 of soil and five plants. Three harvests were performed every 30 days after planting, in a 90-day experimental period. At each harvest, plant height, leaf angle, leaf area, stem diameter, and chlorophyll index (SPAD reading) were evaluated. The best results for the phytometric characteristics and chlorophyll index of paiaguás grass were observed in the wood ash dose of 21 g dm-3. There was a reduction of growth and grass chlorophyll content in the soil water tension of 41.20 kPa.

Nitrogen Fertilization of Paiaguás Grass: Production and Nutrition

“…Regarding Paiaguás palisade grass height Germano et al (2018) on Dystrophic Oxysoil, N rates between 0 to 250 kg ha -1 were evaluated and they observed quadratic responses with the greatest height of 0.59 m using 210 kg ha -1 . Froehlich et al (2019) using the same soil, grass, and N rate, observed a greater height of 0.63 m 150 kg ha -1 of N. Bezerra et al (2019) using Paiaguás palisade grass in the Mato Grosso state region obtained heights between 53.55 and 55.48 cm at 30 and 60 d after sprouting during tests using wood ash as a fertilizer in soils under water stress. Rodrigues et al (2021) using the same grass studied the establishment stage, which resulted in heights of 57 cm at 105 d after sprouting using 55 kg N ha -1 in Quartizarenic Neosoil.…”

“…Furthermore, use of the chlorophyll meter is a fast, making it a practical tool that causes no harm to the plant (Rigon et al 2012) . Bezerra et al (2019) studied Paiaguás palisade grass in Dystrophic Red Oxisol with wood ash fertilization in soil under water stress. They observed an RCC of 41 and 48 with wood ash doses equivalent to 150 kg ha-1 of N. The values they obtained were similar to that found in this study, although the RCC response to tested doses increased with N rates above 250 kg ha-1 after the second cut, as noted in Figure 5.…”

Effects of Fertilization Types and Base Saturation on the Growth and Water Productivity in Panicum maximum cv. BRS Zuri

“…In the treatment composed solely of WA, a fertilization of 24 g.dm −3 was recommended [18]. The WA was incubated together with the soil in closed plastic bags for 30 days, with the moisture adjusted to 60% of the soil's maximum water-holding capacity.…”

“…This combination consisted of 12 g.dm −3 of WA, 75 mg.dm −3 of phosphorus (Simple Superphosphate), 50 mg.dm −3 of potassium (Potassium Chloride) and 50 mg.dm − ³ of FTE (boron: 1.8%; copper: 0.85%; sulphur: 3.9%; iron: 3.0%; manganese: 2.0%; molybdenum: 0.1%, and zinc: 9.0%). For WA, we followed half the P and K recommendation of Bezerra et al [18] and Bonfim-Silva et al [19], respectively, and for micronutrients, we followed the full recommendation of Bonfim-Silva et al [19]. This combination was incorporated into the soil on the day of sowing, which occurred in February 2022.…”

“…Figure 1. 3D sketch representing the distribution of experimental units on benches in the greenhouse with Zuri grass subjected to different fertilization types (Wood ash (WA), Organomineral (OM), and Mineral (M)) associated with different levels of base saturation (0, 25%, and 50%).Each experimental unit consisted of self-irrigating plastic pots with the following dimensions: an external height of 0.18 m; an internal height of 0.14 m; an upper diameter of 0.215 m; a lower diameter of 0.175 m; a pot volume of 5.082 L, and a self-irrigating reservoir volume of 0.96 L.For the first source of variation, three different types of fertilization were used: WA, OM, and M.In the treatment composed solely of WA, a fertilization of 24 g.dm −3 was recommended[18]. The WA was incubated together with the soil in closed plastic bags for 30 days, with the moisture adjusted to 60% of the soil's maximum water-holding capacity.…”