Browsing by Subject "muokkausprofiili"

Starting point for this research was to study the action of spring tine harrow in the perspective of expanding its usage. Farms should keep the investments to machinery at reasonable levels and solution for this are machines with multiple purposes of use, as well as effective tillage systems. Spring tine harrow is effective tool and this study focuses on using it in stubble cultivation in spring, as well as in seedbed preparation. With stubble cultivation there is always the possibility of choking the harrow up with straws which can be solved by making the harrow more permeable with more scattered placement of tines. This leads to the need of broader points and larger tines if the tilling ability is to be kept at the same level. The goal for this research was to study the effects of larger tines, broader points and more scattered tine placement on tillage efficiency of spring tine harrow. Literature review was done in the aim of examining the factors that have effect on the tillage abilities of spring tine harrow as well as looking for studies that operate measuring systems similar the one used in this study. The empirical part of this research was made using field experiments and loading trial in the tine test bench. The treatments used in the research involved 11x45 mm, 10x65 mm, 12x65 mm and 10x45 mm tines and disc cultivation. The tines were equipped with 40 mm, 50 mm and 60 mm points and with 70 mm, 80 mm and 90 mm tine distributions. During the field experiment draft that was needed to pull the test harrow was measured with load cell type sensor, tillage depth was measured with Kritz –method, the roughness of the seedbed was measured with ultrasonic sensor and the clod distribution in the tilled layer with sieving. The soil in the field where the tests were made was silty clay. Bending characteristics of the tines were tested in the tine test bench with loads between 0 - 1000 N. According to results the heavier tines and broader points seemed to be at least as good tillage tools in this test as common s-tines. They produced a very even seedbed and the results from loading tests supported this outcome. Measurements of clod distribution showed no clear distinction between the tested treatments. The draft measurements and the tillage depth measurement did not reach the set objectives due to incorrect test methods as and possible error in the measuring. Otherwise the set objectives for the study were fulfilled.