Study On The Strip Chopping Anti-blocking No-till Planter

Conservation tillage method is being adopted and extended gradually at the present time in northern arid and semi-arid regions of China as a effective method to solve those problems in crop production, like poor grain yield, limited utilization ratio of precipitation, serious soil erosion and low mechanization level. However, one of the most important limitations to conservation tillage is qualified no-tillage planter, and the anti-blocking mechanism is a key component affecting the performance of the planter. In this thesis, a new strip chopping anti-blocking mechanism and a new no-till planter operating well in heavy straw mulching condition are developed from the following aspects:(1)In order to solve the problem that the no-till planters can not work well when the mulched straw is long and thick, especially in the double cropping area of Huabei Plain where the winter wheat gives a high yield, a new strip chopping anti-blocking mechanism was developed. It consists of a group of rotary blades, a narrow tine opener, a shear bar, a hood and a deflector. The testing results of straw cutting and field experiment show that this mechanism has excellent anti-blocking capability.(2)A new no-till planter equipped with the strip chopping anti-blocking mechanism was developed. Compared with other no-till planters, it possesses higher anti-blocking capability and suits the need of seeding in Huabei plain where the winter wheat-summer corn continuous double cropping system gives much straw and short planting season. It still works well when the mulched straw is more then lOt/ha.(3)An experiment was conducted on a self-made testing equipment to investigate the chopping properties of wheat straw under different conditions. On the basis of testing results, main cutting curves of wheat straw were given under different cutting speeds of rotary blade, with different straw lengths, different moisture contents, different cutting position, different thick of knife edge, with and without shear bar. The curves showed that the moisture contents of straw and the shear bar are the main factors impacting the cutting ratio besides cutting speed. The speed of 40mm/s is necessary to cut off wet straw.(4)The testing results indicate that the rotary speed of the blade axle need to be more then1230 rpm (rotary radius of the blade is 25cm) to cut off straw (with moisture content less then 20%).If the straw is wet, higher speed is required. Through theoretical calculation, the critical rotary speedof the axle is 9683rpm. The reasonable blade axle parameters were chosen. The rotary radius is27cm and the rotary speed of the blade axle is 1800rpm.(5)The effect of pressure of twin inclined presswheels on emergence rate under different soil moisture have been compared in field. The experimental results show that the pressure should be 3035kg when the soil moisture is between 11-14%.(6)Through vibration frequency spectrum analysis of no-till planter in field, its vibration characteristics were found out. The main factors causing vibration and the proposed approaches for improving the dynamic characteristics of the strip chopping no-till planter have been discussed.