Growth index in massai grass under different levels of nitrogen fertilization

Abstract

This study aimed to evaluate the growth index of massai grass during two regrowth cycles in a greenhouse under five levels of nitrogen (0, 150, 300, 450 and 600 mg N/dm³ of soil) and eight growth ages (5, 8, 11, 14, 17, 20, 23 and 26 days) in a split-plot design with five replications. The following variables were evaluated: net assimilation rate, herbage growth rate, relative growth rate, leaf area ratio, leaf weight ratio and specific leaf area. The effect of nitrogen was detected on the variables net assimilation rate (regrowths 1 and 2), leaf area ratio (regrowth 1), leaf weight ratio (regrowths 1 and 2), specific leaf area (regrowths 1 and 2) and herbage growth rate (regrowths 1 and 2). The growth ages influenced the relative growth rate (regrowth 2) and the net assimilation rate (regrowth 2). The net assimilation rate presented linear effect, estimated in 0.70 and 2.86 g/m² leaf.day-1 for the 0 and 600 mg N/dm³ soil, respectively (regrowth 1). For each milligram of N/dm³ added, the leaf area ratio was reduced in 0.0000258 m² leaf/g plant (regrowth 1). The herbage growth rate was estimated in 1.38 and 37.02 g/m².day-1 (regrowth 1), and 4.37 and 32.20 g/m².day-1 (regrowth 2) for the 0 and 600 mg N/dm³ soil, respectively. The massai grass' growth is favored by nitrogen fertilization, and little do the growth ages affect the growth index of the plants

Growth Analysis of Brachiariagrasses and ‘Tifton 85’ Bermudagrass as Affected by Harvest Interval

“…Silva et al (2016) compared RGR of irrigated Jiggs and Tifton 85 bermudagrasses harvested every 14, 28, and 42 d and reported differences between grasses but not between the 28-and 42-d harvest intervals. In the present associated with greater amounts of old and shaded leaves (Pedreira et al, 1999;Lopes et al, 2011).…”

“…In the present study, differences among grasses resulted from differences in LAI during growth (Table 3) and in photosynthetic efficiency, as indicated by the greater NAR. Differences in NAR were expected between harvest managements, since longer regrowth intervals are associated with greater amounts of old and shaded leaves (Pedreira et al, 1999; Lopes et al, 2011).…”

The performance of perennial ryegrass in binary mixtures with lucerne and red clover under N fertilization

“…N fertilization did not affect LAR. In research of Lopes et al (2011) abundant N fertilization, significantly reduced LAR what they explained as the result of lower investment in the area of light capture with N fertilization at the expense of investment in the structural components of the plant, as the canopy becomes heavier. In our experiment low doses of N increased LAR, while higher level of N decreased LAR.…”

Producción de materia seca de forrajes en condiciones de Trópico Húmedo en México

“…La mayor TC y PAMS en el Rancho 2 en la mayoría de los meses, puede justificarse por la fertilización con nitrógeno (N) en las praderas de este rancho para mejorar la productividad de los forrajes, ya que la aplicación de N mejora la tasa de crecimiento (Quero, 2007;Améndola et al, 2011;Lopes et al, 2011).…”

“…Most TC and PAMS in ranch 2 in most months, can be justified by fertilization with nitrogen (N) in the grasslands of this ranch to improve productivity of forages, since the application of N improves the rate of growth (Quero, 2007;Améndola et al, 2011;Lopes et al, 2011).…”