Mechanization of Tillage and Seeding on the Sand Cultivating

本研究的目的是为日光温室砂床耕作播种机械化提供基础数据。研制了在钢轨上工作的旋转式和固定式试耕器，并在填沙的耕作床上进行了试验。结果表明：1)所需的耕作功率为0.2~1.4kW，并随土壤含水率的增加而增大；2)耕作前后土壤汽相的变化范围在5%~3.0%之间。土壤水分含量的变化。但当土壤含水率大于3%时，气相的变化量增大到10-40%。这是受砂土的流动性影响，即在干燥条件下休止角较小。可以认为，床上耕作的含水率在4%~6%之间。3)固定耕作刀所需的拉力大于旋耕，且气相增加小于5%。不宜在床上使用固定刀具，干燥的土壤与持水物质混合后，会膨胀到分布的位置，并上升到沙面。在土壤中掺入持水物质，固相含量降低，而气相含量的降低幅度显着小于对照。在土壤的物理性质上表现出与耕作相同的现象。通过一些试验性的实验装置，测量了包衣种子和凝胶中种子的物理性质和释放率。结果表明：1)包衣种子的抗压强度为628~1251gf；2)包衣种子在刷头与种子链轮之间的O mm间隙处的排种精度约为90%。

The object of this study is to obtain the fundamental data for mechanization of tillage and seeding on the bed of sand cultivating in green house. Trial tillage apparatus attached with rotary and fixed tines working on the rails was fabricated and tested on the cultivating bed filled up the sand. The following results were obtained.1) The required power of tillage was the range of 0.2-1.4 kW and increased with increase of the moisture content of soil.2) The variance of the vapor phase of before and after tillage of the soil was within 5% until 3.0% (d. b.) of the soil moisture content. But the variance of the vapor phase increases to 10-40 % when the soil moisture content has more than 3 %. These are influenced by the fluidity of sand, that is, the low repose angle under the dry condition. It is thinkable that the moisture content for tillage on the bed is property between 4 and 6 %.3) Pulling force of the fixed knife for tillage required more than rotary tillage and furthermore the increase of vapor phase is less than 5 %. It is not suitable using the fixed knife for tillage apparatus on the bed.When the dry soil mixed with the holding water substance gets the water, it swells into the position of the distribution and rises up sand surface. The solid phase decreases by mixed with the holding water substance into the soil but the decreasing of vapor phase is remarkable smaller than control. It shows the phenomenon as same as tillage in physical property of soil.The physical properties and discharge rate in the coating seed and seed in the gel were measured by some trial experimental apparatus. The following results were obtained.1) Crush strength of the coating seed was the range from 628 to 1251 gf.2) Discharge accuracy of the coating seed is about 90 % at the O mm clearance between the blush and seed sprocket.