Studies on the Seedbed Making Tillage by Rotary Tiller (III)

On the Shield Performance for the Various Sorts of Tillage Tine

Abstract

This report examines seedbed making performances of various tilling tines (pick tine, knife tine, L-tine) when the tines are used in combination with the shield.
1) Although the tilling power increased when the shield was used, the seedbed making parformances (soil pulverizing, cutting and covering of rice stubble, soil leveling) were improved, and showed an exponential variation with an increase in shield controlling rate C_T.
2) Differences in the seedbed making performances among various tilling tines became small when using the shield, and breaking ratio Rf was in a range from 0.75 to 0.79 when the testing condition was restricted to 40%<C_T<50%, T₀=90mm, and P_i=120mm.
3) Quartile skewness S_q found from a distribution of the pulverized soil diameter became small when the shield was used and difference between various tilling tines also became small when the shieid was used.
4) Weight mean diameter D_W2 of tilled clod was expressed in terms of tilling pitch P_i and shield controlling rate C_T as
D_W2=(A₀⋅P_iⁿ¹) C_T^-n2, mm
where A₀, n₁, and, n₂ were constants.
5) Soil leveling was controlled largely by C_T, and its relationship with D_W2 was also high showing a high significance.
6) The pick tine had a high pulverizing performance and rice stubble disposing performance was also improved by controlling the shield, but entangling of rice stubbles to the tilling rotor and tines became also accelerated at the same time, and pursuance of the normal tilling operation became hard.
7) The L-tine had, in general, a high pulverizing performance, and showed uniform and improved cutting of rice stubbles especially when N₈-N₂₈.
8) Performance of the knife tine approached that of the L-tine with N₄₅-N₈₅, but consumed rather high tilling power.
9) Both the rotor and axle torques increased with an increase in the shield controlling rate. However, the axle torque decresed when tines used consumed a large rotor torque.
10) Fluctuation ratio of the rotor torque was smaller than that with out the shield, but the specific torque for tilling became higher and showed a broader torque distribution.