The aim of this trial was to investigate the effect of different cutting heights on tiller population density and herbage biomass of Buffel grass (Cenchrus ciliaris L) grown in miniature swards in a greenhouse. Four treatments with five replicates: five cm, ten cm, and 20 cm cutting height, and control (without cut) were randomly allocated. Intensity of defoliation affected the cumulative herbage harvested; the ten cm cutting height was greater (404.1 g DM m-2) than 5 cm (317.6 g DM m-2) and 20 cm (263.9 g DM m-2), respectively. Cumulative herbage harvested in the control, increased progressively until September; from then onwards tended to decrease. At the end of the trial, the highest tiller population density was found at five cm cutting height with 28 %, 48 % and 71 % more tillers than ten cm, 20 cm and control, respectively. Herbage mass at five cm and ten cm cutting height, were greater for tiller population density and herbage harvested than 20 cm and control (α\u3c 0.05)

Beltrán, L. S.

García, M. E.

Hernández, G. A.

Herrera, H. J. G.

Kohashi, S. J.

Pérez, P. J.

English

University of Kentucky

University of Kentucky UKnowledge International Grassland Congress Proceedings XIX International Grassland Congress Effect of Cutting Height on Tiller Population Density and Herbage Biomass of Buffel Grass L. S. Beltrán Colegio de Postgraduados, Mexico P. J. Pérez Colegio de Postgraduados, Mexico G. A. Hernández Colegio de Postgraduados, Mexico M. E. García Colegio de Postgraduados, Mexico S. J. Kohashi Colegio de Postgraduados, Mexico See next page for additional authors Follow this and additional works at: https://uknowledge.uky.edu/igc  Part of the Plant Sciences Commons, and the Soil Science Commons This document is available at https://uknowledge.uky.edu/igc/19/1/26 This collection is currently under construction. The XIX International Grassland Congress took place in São Pedro, São Paulo, Brazil from February 11 through February 21, 2001. Proceedings published by Fundacao de Estudos Agrarios Luiz de Queiroz This Event is brought to you for free and open access by the Plant and Soil Sciences at UKnowledge. It has been accepted for inclusion in International Grassland Congress Proceedings by an authorized administrator of UKnowledge. For more information, please contact UKnowledge@lsv.uky.edu. Presenter Information L. S. Beltrán, P. J. Pérez, G. A. Hernández, M. E. García, S. J. Kohashi, and H. J. G. Herrera This event is available at UKnowledge: https://uknowledge.uky.edu/igc/19/1/26 ID # 01-32EFFECT OF CUTTING HEIGHT ON TILLER POPULATION DENSITYAND HERBAGE BIOMASS OF BUFFEL GRASSL.S. Beltrán, P.J. Pérez, G.A. Hernández, M.E. García, S.J. Kohashi and H.J.G. HerreraInstituto de Recursos Naturales. Colegio de Postgraduados, México, sbeltran@colpos.colpos.mxAbstractThe aim of this trial was to investigate the effect of different cutting heights on tillerpopulation density and herbage biomass of Buffel grass (Cenchrus ciliaris L) grown inminiature swards in a greenhouse. Four treatments with five replicates: five cm, ten cm, and 20cm cutting height, and control (without cut) were randomly allocated. Intensity of defoliationaffected the cumulative herbage harvested; the ten cm cutting height was greater (404.1 g DMm-2) than 5 cm (317.6 g DM m-2) and 20 cm (263.9 g DM m-2), respectively. Cumulativeherbage harvested in the control, increased progressively until September; from then onwardstended to decrease. At the end of the trial, the highest tiller population density was found at fivecm cutting height with 28 %, 48 % and 71 % more tillers than ten cm, 20 cm and control,respectively. Herbage mass at five cm and ten cm cutting height, were greater for tillerpopulation density and herbage harvested than 20 cm and control (α<0.05).Keywords: Buffel (Cenchrus ciliaris L), defoliation, tiller population density, HerbageharvestedIntroductionBuffel grass (Cenchrus ciliaris L) is African specie introduced to Mexico and twomillion ha is currently established (Ibarra, et al., 1991). This grass has been favored for its greatpotential for the semiarid lands, due to high tolerance to drought, high yield, easy establishmentand good response to grazing management. However, important losses occur every year, due toinadequate management, especially overgrazing. The main factor that affects the growth, yieldand persistence of swards, is the defoliation intensity. The severity of defoliation causesphysiological and morphological changes at plant level, especially during the regrowth period(Briske, 1986). The regrowth after defoliation, is one of the most important physiologicalprocesses, and it determines the sward structure (Matthew et al, 1995). The higher leaf area indexof a pasture promotes the greater incident radiation interception at the canopy and duringregrowth; pasture growth rate increases until the point where 95-100 % of incident light isintercepted (Mott, 1981; Chapman and Lemaire, 1993). Intense grazing usually increases tillerdensity and induces a high irradiation interception in the swards (L’Huillier, 1987), however abalance should exist in the growth-defoliation relationship, because an intense grazing mightseriously limit grass growth, due to the low amount of the remaining leaf area (Matthew et al.,1995). Leaf size is highly responsive to variation in defoliation intensity, owing simply toincreased stocking rate, or to differences in defoliation patterns associated with different grazingmethods (Chapman y Lemaire, 1993). Korte and Parson (1984) postulated that small tillers wouldbe more tolerant to intensive grazing regime by virtue of their ability to retain a greaterproportion of leaves below the grazing horizon and thus maintain a more stable supply ofassimilates for regrowth. According to Hernandez et al (1999) herbage biomass is a function ofthe height defoliation, tiller weight and tiller population density. The aim of this study was toinvestigate the effect of cutting height intensities on tiller population density and herbageharvested in Buffel grass.Material and MethodsMiniature swards of Buffel grass (Cencrhus ciliaris L), were established from seed inplastic pots 25 cm of diameter and 20 cm depth, in may 1998 and grown in a greenhouse atPalma de la Cruz (INIFAP) research station, San Luis Potosi, Mexico (22º 12’ 00’’ N, 100º55’18’’ W). The experimental period was ten months duration (may 1998 to march 1999). Thepots were randomly allocated to four treatments (five, ten, 20 cm cutting heights and the control(without cut), with five replications. Each pot contained four kg of sandy loam soil. The sowingrate was equivalent to 3 kg seed ha-1. Once the seedlings were established, 40 kg ha-1 of nitrogenwas supplied, equivalent to 3.0 g per pot as urea. Each pot was watered daily. Clippings beganwhen the plants had reached 25 cm height (26 May 1998), 40 days after seedling (16 April 1998).Afterwards, clipping was done every week, according to the cutting height. Herbage harvestedwas collected, dried at 65 ºC and weighed. Tiller population density was recorded weekly. Datawere submitted to analysis of variance (α<0.05) using the General Linear Model (GLM)procedure of SAS (SAS, Institute Inc. 1991).Results and DiscussionThere were statistical differences among treatments in cumulative herbage biomass (α<0.05). From the beginning to September, cumulative herbage mass was higher under the control,however, from then onwards; it decreased, whereas it increased under the other treatments. At theend of the trial, cumulative herbage mass was ranked as follow: ten cm > five cm > 20 cm cuttingheight > control, respectively (Figure 1). The low herbage harvested in control, might be aconsequence of increased leaf senescence. In this sense, Hunt (1970) mentions losses bysenescence and decomposition increase to a maximum during uninterrupted growth of a sward.The highest cumulative herbage biomass under 10 cm cutting height may be due to higher singletiller weight, just as Hernandez et al, (1999) refers to the highest herbage harvested being afunction of the height of defoliation, tiller weight and tiller population density. The weeklyherbage harvested for ten and five cm increased steadily from november until the end of thestudy.Tiller population density, at the beginning of the experiment (26 May 1998), averaged172 tillers m-2. Tiller population density increased progressively in all treatments, from March(1998) until January (1999). From then onwards tended to decrease at 20 cm cutting height andcontrol (Table 1). At the end of the trial (February - March, 1999), tiller population density washighest at five cm cutting height (2343 tiller m-2). Treatments were ranked as follow: five cm >ten cm > 20 cm > control, respectively. This behavior can be explained by the size-densitycompensation index, where the least size of tillers, is compensated by the high tiller populationdensity (Hernández, et al. 1999). According to Chapman and Lemaire (1993), when severity ofdefoliation increases, morphological adjusts are needed to ensure homeostatic whole plantgrowth. The higher herbage harvested on ten cm cutting height may be explained by the highersingle tiller weight. In this trial the more severe treatments (ten and five cm), probably causedmorphological changes at plant level. In summary, the different cutting heights affect the tillerpopulation density and herbage biomass of Buffel grass.ReferencesBriske, D.D. (1986).  Plant response to defoliation: morphological considerations and allocationpriorities. In: Joss, P. J., Lynch, P. W., Williams, O. B. Eds. Rangelands: A resource under siege.Cambridge, Univ. Press. Pp 425-427.Chapman, D.F and Lemaire G. (1993).  Morphogenetic and structural determinants of plantregrowth after defoliation. Proceedings of the XVII International Grassland Congress p. 95 - 104.Hernández, G.A., Matthew C. and Hodgson J. (1999). Tiller size/density compensation inperennial ryegrass miniature swards subject to differing defoliation heights and a proposedproductivity index. Grass and Forage Science 54: 347-356.Hodgson, J., Bircham J.S., Grant S.A. and King J. (1981). The influence of cutting andgrazing management on herbage growth and utilization. In: Wright, C. E. Ed. Plant physiologyand herbage production. The British Grassland Society. Occasional Symposium. Number 13: 51-62.Hunt, W.F. (1970). The influence of leaf death on the rate of accumulation of green herbageduring pasture regrowth. Journal of Applied Ecology. 7: 41-50.Korte, C.J. and Parsons A.J. (1984). Persistence of a large-leaved white clover variety undersheep grazing. Proceedings of the New Zealand Grassland Association. 45: 118-123.L’ Huiller, P.J. (1987). Effect of dairy cattle stocking rate and degree of defoliation on herbageaccumulation and quality in ryegrass-white clover pasture. New Zealand Journal of AgriculturalResearch 30: 149-157.Ibarra, F.F.A. (1991). Utilización, manejo y mejoramiento de praderas de zacate buffel. Enmemorias del taller sobre captación y aprovechamiento del agua con fines agropecuarios. SARH- INIFAP Comarca Lagunera. P. 191 - 200Matthew, C., Lemaire G., Sackville N.R.  Hamilton A. and Hernández G. (1995). A modifiedself-thinning equation to describe size/density relationships for defoliated swards. Annals ofbotany 76: 579-587.Mott, G.O. (1981).  Potential productivity of temperate and tropical grassland systems.Proceedings of the XIV International Grassland Congress: 35 - 41.SAS Institute Inc. (1995). User's guide. Statistics. Version 6. Forth edition. SAS Inc. Cary,North Carolina, USA. 956 p.Table 1 - Effect of cutting height on tiller population density (tillers m-2) of miniatureswards of Buffel grass1998 1999CuttingHeight (cm) M J J A S O N D J F M5 187 302 391 654 877 1069 1014 1409 1571 2266 234310 165 304 407 791 1152 1442 1447 1897 2019 1917 168620 171 299 405 709 1003 1240 1234 1293 1209 1126 1217Control 162 254 317 529 759 994 1143 1149 1008 811 686s.e.m.Significance0.52ns0.74*1.26*3.16*4.99*7.29*7.63*7.20*9.53*10.04*10.51*Figure 1 – Effect of cutting height on cumulative herbage biomass ofBuffel grass miniature swards (1998-1999).050100150200250300350400450M J J A S O N D J F MMonthg DM m-25 10 20 Control

Effect of Cutting Height on Tiller Population Density and Herbage Biomass of Buffel Grass

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Effect of Cutting Height on Tiller Population Density and Herbage Biomass of Buffel Grass

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