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Response to defoliation

Response to defoliation. What is defoliation การริดรอนใบพืช Grazing Cut What are feature in response to defoliation ? Frequency ความถี่ จำนวนรอบที่ปล่อยสัตว์เข้าแทะเล็ม / ตัด Intensity ความรุนแรงของการแทะเล็ม / ตัด

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Response to defoliation

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  1. Response to defoliation • What is defoliation การริดรอนใบพืช • Grazing • Cut • What are feature in response to defoliation ? • Frequency ความถี่ จำนวนรอบที่ปล่อยสัตว์เข้าแทะเล็ม / ตัด • Intensity ความรุนแรงของการแทะเล็ม / ตัด • Time in relation to growth stage of pasture ฤดูกาล และช่วงอายุการเจริญเติบโตของแปลงหญ้า

  2. Structure of grass plant apical / flower primordia culm bud & tiller primordia crown

  3. STRUCTURE OF LEGUME PLANT shoot with flower crown root with nodule

  4. Sward dynamics Growth new tissue added Green herbage Senescence Decay dead herbage removed by worms & micro-organisms Dead herbage Pasture production tissues eaten by stocks

  5. New pasture growth Growth / production (kg DM/ha) Decay Net pasture production 900 - 1200 Pasture mass (kg DM/ha)

  6. Gumboot technique • Graze the pasture depending on the availability of the herbage and the recovery of the pasture after grazed.

  7. Grazing vs. Cutting • Selectivity by animal • species preference or palatability • plant parts: leaf is more preferable to stem • Trampling • Excretion • Animal behavior : grazing vs. browsing

  8. ตัวอย่างการจัดการที่ดีตัวอย่างการจัดการที่ดี • แปลงหญ้ารูซี่และซิกแนลเลื้อยในสวนมะพร้าวที่ ต. ไพรวัลย์ อ. ตากใบ จ นราธิวาส เป็นตัวอย่างของ moving shed ที่สามารถหมุนเวียนธาตุอาหารพืชลงสู่แปลงได้สะดวก • แปลงหญ้าเนเปียร์และฟาร์มโคนมที่ อ.ปากช่อง จ. นครราชสีมา เป็นตัวอย่างของการจัดการแรงงานในระบบการคืนมูลสัตว์สู่แปลงหญ้าที่ตัด และอยู่ห่างจากคอกสัตว์

  9. Plant response to defoliation • Reserved carbohydrate in stubble • Effect on growth of root and shoot bud • LAI to intercepted light • Mortality of the sward tiller density, % coverage • Climatic factors eg. rain, soil moisture, temperature ect.

  10. Effect of defoliation to physical environment grazing regimes • water run off • water penitration • evaporation • wilting after drought • frost damage • growth form linient less high less quicker less less change heavy higher less higher less more tillering

  11. How do plant survive after defoliation ? • Less intensity ie removal of leaves or bud primordia is not so severe • Capacity of plant to form new shoot and leaf • Recruitment through seed • Recruitment through stolon and rhizome

  12. Differences in defoliation intensity are due to • Cutting height • Selective grazing • physical and anatomical form of plant • chemical substance ; silica, coumarin • animals are get use to • seasonal and palatability of plant

  13. Pasture growth vs production under defoliation regimes Desmodium + Cynodon Cutting intervalsintortum dactylon (weeks) (ton/ha/yr) (%) 4 4.2 62 7.0 8 6.5 72 9.1 12 8.0 81 10.0 mean over 3 cutting height : 3.8 , 7.5, and 15 cm source: Jones, R.J. 1973

  14. Effecting of defoliation on regrowth and plant form • crown , root and LAI • increase leaf content : leafy sward • enhance branching if cut at juvinile stage • severe defoliation will decrease reserved CH2O and plant vigor • after cut there will be enough leaf to intercept 95 % of light is desired • the more Total Available CH2O is better

  15. The relationship between intake and pasture characters Nutritional limited Non nutritional limited Pasture intake (kg DM/ha) Pasture weight (kg DM/ha), height (cm), post grazing mass (kg DM/ha)

  16. Non-nutritional limited vs Nutritional limited • pasture nutritional quality • digestibility • legume component • pasture structure • pasture allocation • grazing behavior of animal • diet selection • grazing time • bite size • rate of biting

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