Malan, P. J.

Snyman, Hennie A.

English

University of Kentucky

University of Kentucky UKnowledge International Grassland Congress Proceedings XXI International Grassland Congress / VIII International Rangeland Congress Dry Matter Production and Partition of Two Palatable Karoo Shrubs P. J. Malan University of the Free State, South Africa Hennie A. Snyman University of the Free State, South Africa 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/21/10-1/50 The XXI International Grassland Congress / VIII International Rangeland Congress took place in Hohhot, China from June 29 through July 5, 2008. Proceedings edited by Organizing Committee of 2008 IGC/IRC Conference Published by Guangdong People's Publishing House 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. 瞯 ]238　 瞯 　 Multifunctional Grasslands in a Changing World 　 Volume Ⅱ 　Grasslands/Rangelands Production Systems——— Integration of Crops , Forage and Forest SystemsDry matter production and partition of two palatable Karoo shrubsP .J . Malan , H .A . SnymanDepartment o f A nimal , W ildli f e and G rassland Sciences , P .O . Box 339 , University o f the Free State , Bloem f ontein 9300 ,South A f rica . E‐mail : malanp j .sci＠ u f s .ac .z aKey words : edible ,inedible ,root productionIntroduction It is taken for granted that Karoo shrubs ( bushes) are well adapted to only the soils and climate of the Nama Karoobiome in South Africa . The easterly movement of Karoo vegetation into the Grassland biome ( dominated by grasses) is howeverwell documented , while ecosystems responding to global climate change are a new debate . The dry matter ( DM ) productionand structure of two palatable shrubs from the Nama Karoo biome were evaluated on two different soil types .Material and methods The plants Nenax microphy lla and Pentz ia incana , and one soil type were collected from GrootfonteinAgricultural Development Institute at Middelburg Eastern Cape in the Nama Karoo biome ( Valsrivier form‐４０ ％ clay content ,annual rainfall ３６５mm) , while the other soil type was from Bloemfontein in the Grassland biome ( Bainsvlei form‐１４ ％ claycontent , annual rainfall ５３０mm) . One plant of each species was vegetatively multiplied by means of stem cuttings . This meansthat six clones of each species were used and therefore the different plants of each species were genetically identical . Threeplants of each species were planted in each soil type in pots in a glasshouse . Pots were watered once a week with the samevolume of water . Dry matter production and its partition ( roots , inedible stems , edible stems and leaves) were determined byharvesting all plants destructively after six months of grow th .( Malan , ２０００) . Edible stems were those with a diameter of lessthan two millimeters (Du Toit , １９９６) .Results The total DM production ( above ground plus below ground ) of P . incana was on average ５８ .９７ g / plant on theGrassland soil and only ４４ .７４ g / plant on the Karoo soil , while that of N . microphy lla was also higher in the Grassland soil at６３ .９３ g / plant compared to ５１ .５３ g / plant on the Karoo soil . The percentage contributions of different plant components wasvirtually the same for each species in both soil types , with N . microphy lla producing a higher percentage of edible materialthan P . incana . Root development and production of both species was higher in the Grassland soil with the lower clay content( Table １ ) . Plants in the Grassland soil wilted earlier than those in the Karoo soil , which might be due to the higher claycontent (４０％ ) of the Karoo soil ( Table ２) . Even though the mineral content of the grassland soil was slightly lower ( Table２ ) , it still showed the highest production . The higher soil pH level of the clay soil might inhibit the availability of the soilnutrients .Table 1 Percentage contribution o f di f f erent p lant components toaverage DM p roduction per species , as well as the root / shoot ratio .Species Roots Leaves andedible twigs( ％ )Inedibletw igsRoot / shootratioGrassland soilN . microp hy lla １５ 煙８１ �４ G０ 篌.１８P . incana １７ 煙７３ �１０ \０ 篌.２０Karoo soilN . microp hy lla １３ ⅱ８２ ６ H０ 祆.１４P . incana １２ ⅱ７６ １２ _０ 祆.１６Table 2 Soil analysis results f or the two soil ty pes .Ca K Mg Na P Clay pH　 ppm 　 ( ％ )Grassland soil ( Bainsvlei form )４８６ 侣２００ 汉１５４ 亮２５４ 热２２ １４ ６ 祆.１Karoo soil ( Valsrivier form )１９０８ 种３２０ 汉９００ 亮３２０ 热１１ ４０ ７ .８Conclusions Surprisingly , plants generally grew better on the Grassland soil than on the Karoo soil , which might be ascribed tothe better root development in the Grassland soil . The plants might persist longer in the Karoo soil with its higher clay content ,which will enhance water retention , and higher nutritional value . Although a lower DM production in the Karoo soil over theshort term , the tested plant species might over a longer period survive better in the Karoo soil . This study clearly indicated theadaptability of Karoo shrubs to different soil types which might be important for vegetation changes and movements due toglobal warming .ReferencesDu Toit , P .C .V . , １９９６ . Karoobush defoliation in the arid Karoo . Journal o f Range Management ４９(２ ) : １０５‐１１１ .Malan , P .J . , ２０００ . Selection and propagation of elite A trip lex material . MSc . Agric . Dissertation . University of Pretoria ,South Africa , ２１‐５８ .

Dry Matter Production and Partition of Two Palatable Karoo Shrubs

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Dry Matter Production and Partition of Two Palatable Karoo Shrubs

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