| Corn is one of the most widely distributed food crop in the world. Planting ra nge from 58 degrees north latitude to 40 degrees of south latitude. It is also widel y distributed in China, and is one of the most important food crops for the people in northern china and southwest and other arid mountainous valley region. In Chin a,arid, semi-arid and dry sub-humid areas account for 52.2% of the whole land, a nd dry crops have a planting area of about 33 million square kilometers which dist ributed in north of 16 provinces, municipalities municipalities and autonomous regio ns. Under conditions with limited land resources, to improve food production and i ncrease yield of grain, it is essential to develop agricultural machinery. Since the so wing machinery is an important part of agricultural machinery, the development of corn so wing machine has become one of the key issues to improve the yield of corn.Recent years, with the promotion of no-tillage and sub-soiling corn planter in large ar eas of North China Plain, the no-tillage sub-soiling and whole layer fertilization corn seede r developed by our research group can achieve zero tillage sub-soiling, whole layer fertilizi ng, precise planting, soil and compaction, and many other functions. And it can also meet t he requirements of precision sowing in terms of the high precision metering, single grain ra tio and breakage rate. Thanks to sub-soiling, the permeability and water storage capacity ha ve been improved, and the efficiency of water and fertilizer use has been improved, and the se in turns have promoting effects on corn yield. But because of the traditional operation th at rotary tillage depth is not enough, the active soil layer becomes shallow and the deeper s oil becomes hard plough layer soil, and there will be large amounts of crop residues when s ub-soiling. In addition, inconsistent sowing depth and uneven seedling emergence are als o the problems which badly affect the yield of corn. In order to solve these problems of th e no-tillage sub-soiling and whole layer fertilization corn seeder, this paper developed the p re sowing cult-packer roller, which aimed to increase the yield of corn by breaking the larg e clods, keeping a consistent sowing depth and ensuring even seedling emergence.Aiming at the above problems of the no-tillage sub-soiling and whole layer fertilizatio n corn seeder, this paper put forward an improving solution, which is installing a cult-pack er roller device behind the whole layer fertilization sub-soiler, before the furrow opener t o act as a driving force in the process of soil crushing. By analyzing the crushing method of the soil crushing roller, this paper figured out four surface structures of the rollers; by ana lyzing the shapes of soil after furrow and the relationship between the traction force and w heel diameter, the paper measured out the diameter and width of the soil crushing rollers, a nd drew three-dimensional graphics of the four crushing rollers with Pro/E drawing softwa re. Besides the theoretical dynamics analysis of the soil crushing roller, we also made the fi eld tests of it. Four kinds of soil crushing rollers were put into the field tests in 3 fields wit h different soil bulk density and moisture content. By the comparative analysis of the numb ers of blocks with different diameters and the comparative analysis of the clay rates and sli p rates, we observed the crushing effect of the four kinds of soil crushing rollers, and finall y elected the best one.In the field tests we can see, after the use of pre-sowing soil crushing roller, the clod s decreased remarkably. And considering about the soil breaking rates, clay rates and slip r ates, the soil crushing roller No. 2 is the best. |
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