Organic Reserves in ropical Grasses under Grazing

Abstract

Inadequate management in recent times has been considered the main factor contributing to pasture degradation. A major reason for this is related to gross errors of grazing management as a consequence of the lack of knowledge of ecophysiological limits of forage. This review aimed to approach the importance of organic reserves for grasses under grazing. Therefore, the predominant effect of animal grazing is the reduction of leaf area which impacts on carbohydrate and nitrogen reserves and consequently the growth of tillers, leaves and roots. Grass growth after defoliation is related to organic reserves and rate of photosynthesis. The latter is affected by the level of canopy light interception of and by the reminiscent leaf area index. When grazing management is carried out with respect to the physiological limits of grass growth, the rate of dry matter accumulation will be quick and constant. In this aspect, grazing management consists of seeking an efficient balance between plant growth and consumption which will reflect on animal productivity. Therefore, a balance point among frequency and intensity of defoliation must be found to achieve greater animal production concerning the ecophysiological limits of the forage plants. So the challenge will be to find a balance between frequency and intensity of grazing to achieve greater production of animals respecting the eco-physiological limits of forage plants for each forage grass individually.

Morphogenetic and Structural Characteristics of Guinea Grass Pastures Under Rotational Stocking Strategies

“…This way, the plant responses to the defoliation disturbance must be understood as a mechanism of re-establishment and maintenance of the growth patterns, where all the factors available must be utilized for the formation of new photosynthetic tissues (Lemaire and Chapman, 1996). In this scenario, it has been demonstrated that the leaf appearance rate increases with reduction in the sward leaf area index, in conjunction with the high levels of blue light (400 to 500 nm) and the higher red (600 to 700 nm):far-red (700 to 800 nm) ratio at this condition (Ferro et al, 2015). So, it was expected that the greater defoliation frequencies and lower post-grazing heights would result in greater Guinea grass cv.…”

“…In this scenario, it has been demonstrated that the leaf appearance rate increases with reduction in the sward leaf area index, in conjunction with the high levels of blue light (400 to 500 nm) and the higher red (600 to 700 nm):far-red (700 to 800 nm) ratio at this condition (Ferro et al ., 2015). So, it was expected that the greater defoliation frequencies and lower post-grazing heights would result in greater Guinea grass cv.…”

“…As for leaf senescence rate, its highest value occurred in the winter and beginning of the spring (Table 4). It is possible that, with the increase in temperature, solar radiation and soil humidity at the beginning of the spring (Figures 1 and 2), leaves began senescence immediately, in order to supply nutrients and, consequently, help the expansion of new leaves, via greater translocations of nutrients from the senescing organs to those under development in the plant (Ferro et al ., 2015). In fact, there is possibility that 50% of the carbon and 80% of the nitrogen being recycled from the senescing leaves and being utilized by the plant for the synthesis of leaf tissues (Lemaire and Agnusdei, 2000).…”

Forage quality and performance of sheep in Massai grass pastures managed at pre-grazing canopy heights

“…Nevertheless, studies on the management of this forage in semiarid regions are still scarce (Martuscello et al, 2015). According to Ferro et al (2015), the great challenge in pasture management is to find the balance between frequency and intensity of grazing in order to achieve greater animal production, in terms of the eco-physiological limits of the plants.…”

Mowing and lowering the marandu palisadegrass sward height at late winter improve the sward structure

“…In this condition, the tillering is stimulated (MATTHEW et al, 2000). In addition to this fact, it is also possible that marandu palisadegrass had a high stock of reserve compounds during late winter, because the grass growth is low at this season and so is the demand for these compounds (DA SILVA et al, 2014;FERRO et al, 2015).…”