Effects Of Different Harvesters On Harvesting Efficiency Of Cassava

Cassava(Manihot esculenta crantz(M.utilissima Pohl)),one of three tuber crops(cassava,potato,sweet potato)in the world,is praised as "king of starch" and "underground foodstuff",being the main crop in Chinese tropic region.Yet its low harvesting efficiency has a strong impact on sustainable development of cassava.The test applied three cassava harvesters to analyze the influence of different cassava harvesters on travel speed,harvesting productivity,uprooting speed,uprooting force,manual operation force,and cost when harvesting cassava,and to screen proper cassava harvester,thereby providing scientific reference for solving low efficiency and high cost in harvesting cassava in hilly ground.The main research findings are:1.Different cassava harvesters have different travel speeds.No.3 harvester is the fastest,No.2 comes the second,and No.1 is the slowest.Wherein the travel speed of No.3 is 2.93 times of that of No.2,and 4.72 times of No.1,while that of No.2 is 1.61 times of No.1.The travel speed of No.3 is 1.558m·s-1,greater than 1m·s-1,a fast speed which is applicable to production,while the travel speed of No.1 and No.2 <1m·s-1,a too slow speed which is not applicable to production.2.Different cassava harvesters have different uprooting speed and uprooting force.The maxima and minima of uprooting force for No.1 are largely different,so are No.2 and No.3.The largest uprooting force of three harvesters is not significantly different.The maxima and minima of uprooting speed for No.1 are not significantly different,so are No.2.The maxima and minima of uprooting speed for No.2 are largely different.The No.3 has the fastest uprooting speed,while No.2 comes the second,and No.1 is the slowest.Wherein the uprooting speed of No.3 is significantly higher than that of No.2 and No.1,being 2.93 times of that of No.2,and 4.91 times of that of No.1,while that of No.2 is not significantly different from that of No.1,being 1.66 times of No.1.3.Different harvesters and harvesting modes have significant effects on harvesting time and harvesting efficiency of individual cassava.The average manual harvesting time for individual cassava is 1.36min·cassava-1,3.02min·cassava-1 for No.1,2.06min·cassava-1 for No.2,0.4min·cassava-1 for No.3.The harvesting efficiency of No.3 is apparently higher than manual harvesting,improving by 3 times than manual harvesting,and 7.78 times and 6.85 times than No.1 and No.2 respectively,while the harvesting productivity of No.1 and No.2 is all lower than manual harvesting,being 42.96% and 41.63% lower than manual harvesting respectively.Wherein the harvesting productivity of No.1 is lower than that of No.2,being 22% lower than No.2.4.Different harvesters have significant effects on harvesting cost of cassava.Calculating by 100 Yuan·day-1 for manual harvesting cost,the harvesting cost of No.1 increases 4442 Yuan·hectare-1 than manual harvesting,that of No.2 increases 2776·hectare-1 than manual harvesting,While that of No.2 increases 2917 Yuan·hectare-1 than manual harvesting.It is observed that proper harvester used to harvest cassava can dramatically lower harvesting cost.