Impact of Clipping on Root Systems of 3 Grasses Species in Tunisia

Abstract

The study concerns the impact of herbivory on the root systems of 3 perennial grasses, huffelgrass (Cenchnrs ctiti), digitgrass (Digitaria commutata) and needlegrass (Stipa lagascae), growing in the arid zones of Tunisia. The study simulated animals feeding of the grasses by affecting cuttings at various times throughout the spring growing period. The following effects on the root systems of the grasses were observed.When there is continual overgazing (simulated by cutting all sprouts down the ground level-along the spring), more than 65% of the roots off all 3 species are found in the salty upper 15 cm of soil.In case of medium average grazing (simulated by 2 to 3 cuttings), the root system again remains superficial for buffelgrass (C. c&z&), with 58 to 67% of the roots located in the upper 15 cm of soil. Digitgrass (Digitaria commutata) and needlegrass (Stip Zugascae), however, develop deeper roots with 68 to 86% in the upper 30 cm of soil.When grazing is light (just one cutting), all 3 species perform all most exactly as if there had been no grazing compared to (a control plot) with 85% of the root system located in the upper 50 cm and about 15% at 50 to 75 cm of ground depth.On the basis of this experiments, it is suggested that grazing on these grasses should be allowed just once each spring, thereby allowing : l-To take advantage of the aboveground contained in these grasses in spring.2-Preservation of a deep root system with will thereby have a much better chance of getting through the water stress summer $zl?axlIl.

Relações entre produtividade de Brachiaria Brizantha e atributos físicos de um latossolo do cerrado

“…A relação inversa dos pares MS x RP2 e MS x RP3 evidenciou que com o aumento da RP houve diminuição da MS, proporcionada pelo aumento da compactação do solo na camada de 0,10-0,30 m de profundidade e, portanto, provavelmente pelas condições adversas ao crescimento radicular, uma vez que as raízes da braquiária apresentam maiores concentrações nas camadas mais profundas, se não forem superpastejadas. Assim, a relação inversa da MS x PT3 (r = -0,205*) e a direta entre MS x DS3 (r = 0,204*), provavelmente, podem ser atribuídas ao maior contato solo/raiz, com maior eficiência de absorção de água e nutrientes, incrementando a MS. Chaieb et al (1996), trabalhando com o capim Cenchrus cilliaris, demonstraram, no caso de dois a três cortes (simulação de pastejo leve), que o seu sistema radicular permaneceu superficial, com cerca de 58 a 67 % das raízes localizadas nos primeiros 15 cm da camada superficial de solo. No entanto, para as gramíneas Digitaria commutata e Stipa lagascae houve aprofundamento das raízes, localizando-se 68 a 86 % delas a 30 cm de profundidade.…”

Phosphorus fertilization and growth of buffel grass (Cenchrus ciliares L.) cultivars

“…The buffel grass has features that make it competitive to survive in arid and semiarid conditions, among them a deep root system which according to Halvorson & Guertin (2003) allows access the water supply faster and for longer time than the native species. Thus, it is important to observe the development of the root system to develop management strategies of buffel grass (Chaieb et al, 1996;Mnif & Chaieb, 2009). In this study, it was observed that increasing doses of P promoted the linear development of the root system, showing the competitive strategy and adaptive of the specie.…”

The polyploid nature of Cenchrus ciliaris L. (Poaceae) has been overlooked: new insights for the conservation and invasion biology of this species – a review

“…Despite its wide distribution, the expansion of overgrazing associated with the severity of climatic factors in arid ecosystems has led to a continuous thinning of stands and the threat of extinction of this species throughout its natural area of occurrence (Chaieb et al 1996;Whitford 2002). Considering the ecological interest offered by C. ciliaris: drought tolerance (Bhatt et al 2007; De La Barrera and Castellanos 2007;Kharrat-Souissi et al 2012a), high fodder production and nutritive value to livestock (Kharrat-Souissi et al 2010;Arshadullah et al 2011), rapid regeneration in response to rainfall (Bose and Balakarishnan 2001), tolerance of heavy grazing (M'seddi et al 2004a) and soil stabilisation abilities because of a deep root system (Chaieb et al 1996;Mnif and Chaieb 2009), the persistence of this species in its native range in arid ecosystems is a crucial factor for restoration ecology of degraded arid rangelands.…”

“…Despite its wide distribution, the expansion of overgrazing associated with the severity of climatic factors in arid ecosystems has led to a continuous thinning of stands and the threat of extinction of this species throughout its natural area of occurrence (Chaieb et al 1996;Whitford 2002). Considering the ecological interest offered by C. ciliaris: drought tolerance (Bhatt et al 2007; De La Barrera and Castellanos 2007;Kharrat-Souissi et al 2012a), high fodder production and nutritive value to livestock (Kharrat-Souissi et al 2010;Arshadullah et al 2011), rapid regeneration in response to rainfall (Bose and Balakarishnan 2001), tolerance of heavy grazing (M'seddi et al 2004a) and soil stabilisation abilities because of a deep root system (Chaieb et al 1996;Mnif and Chaieb 2009), the persistence of this species in its native range in arid ecosystems is a crucial factor for restoration ecology of degraded arid rangelands. For these reasons, C. ciliaris has been the subject of numerous applied studies, which have focussed on its phenotypic polymorphism, its ecological significance (M'seddi et al 2002;Arshad et al 2007;Jorge et al 2008;Visser et al 2008;Kharrat-Souissi et al 2010;Arshadullah et al 2011), resistance to drought (Mansoor et al 2002;Mnif and Chaieb 2010;Kharrat-Souissi et al 2012a), biological invasion capacity (Friedel et al 1996;Franklin et al 2006;GutierrezOzuna et al 2009;Marshall et al 2012) and its genotypic diversity (Nisar et al 2010;Al-Soqeer 2011;Kharrat-Souissi et al 2011).…”

“…Because perennial herbaceous plants result in higher levels of ground cover and persist for longer than annual species, they are the most intensively grazed by cattle (Chaieb et al 1996). They are the species most affected by dryland degradation and constitute one factor contributing to desertification (Whitford 2002;Jauffret and Visser 2003).…”