Abstract
Abstract: In transitory and busy farming season, the straw has to be buried in the field whether it’s paddy or dry land. In this study, we designed a straw burying rotary tiller, which can bury crop straw not only in paddy field, but also in dry land. It is suitable for tillage in middle and lower reaches of Yangtze River, where the principal crop rotation is paddy field rice after dry land crop annually. In order to improve the working quality of the cultivating roller for straw returning in paddy field and dry land, the experimental studies have been conducted in the fields. First, L9(34) orthogonal experiment was conducted to research the influence factors of the performance of the cultivator for straw returning. The main influence factors for working quality of rotary tiller were tillage depth, rotary speed and forward speed. The tillage depth of 15.5, 18.5 and 21.5 cm, the rotary speed of 314, 330 and 360 r/min, and the forward speed of 0.43, 0.69 and 0.93 m/s were selected. The results showed that among the above 3 factors the influence order was tillage depth>forward speed>rotary speed. The tillage depth affected straw coverage extremely significantly, the forward speed affected straw coverage extremely significantly, and the rotary speed didn’t affect straw coverage obviously, but it affected soil crushing rate significantly. The better test conditions were shown as below: the forward speed was 0.43-0.93 m/s, the rotary speed was about 330 r/min, and the tillage depth was about 21.5 cm. Based on the better test conditions (the forward speed was selected as 0.43 m/s), the experiments on working performance of cultivator for straw returning in paddy field and dry land were conducted in the fields, and the wireless telemetry technology and the power output shaft torque sensor were used in the study. The results showed that the working qualities of cultivator which met the agro-technical requirement of rice sowing and transplanting were as follows: in paddy field, when the soil texture was clay loam, the soil water content was 42.6%, the height of straw was 78.9 cm, the tillage depth was about 150 mm and the soil compaction value was under 1 244.8 kPa, the vegetation coverage rate reached 94.3%, the tillage depth reached 20.8 cm, the stability of tillage depth was 92.3%, the field surface evenness was 0.9 cm, and the power consumption was 27.6 kW; in dry land, when the soil texture was loam, the soil water content was 25.8%, the height of wormwood was 97.2 cm, the tillage depth was 150 mm and the soil compaction value was under 2 310.5 kPa, the vegetation coverage rate reached 96.5%, the tillage depth reached 20.3 cm, the stability of tillage depth was 90.6%, the field surface evenness was 1.2 cm, and the power consumption was 31.2 kW. At the same time, the comparative tests between the combination blade roller and the spiral blade, the traditional rotary blade were also conducted, in which the new roller was in according with the national standard of the work quality. The results showed that the working quality of the combination blade roller was better than that of the spiral blade and the traditional rotary blade, and the power consumption of the combination blade roller was higher than that of the traditional rotary blade. Based on the above results, further research on the power consumption of the cultivator for straw returning in paddy field and dry land is needed. The results provide the basis for the structure optimization of the cultivator for straw returning and the improvement of its working performance, and also provide a suitable implement to achieve high stubble straw mulching and soil tillage in paddy field and dry land.
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