Rancang Bangun Ditcher Berpengeruk untuk Pembuatan Saluran Drainase pada Budidaya Tebu Lahan Kering

Abstract

One factor determining the sugar cane production is a good drainage system. The drainage channel that crosses the planting rows is used to drain the excess water from sugar cane plantation. The drainage channel at PG. Jatitujuh has been being formed by using a rotary ditcher. Shape and dimension of the drainage channel were good enough as expected, but the rotary ditcher itself had some disadvantages such as: its blades became dull and worn quickly, it tend to break the tractor PTO system. On the other hand, the utilization of a furrower in the ditch forming is preferred. But, the resulted shape and dimension channel was not good enough. The soil dug out from the ditch covered both sides of the planting rows along the channel. Consequently, it blocked the drain water flow out from the planting rows. The objective of the research was to design a ditcher equipped with a pair of scrappers pulled by a four-wheel tractor. The ditcher operated without using PTO. It’s designed to produce drainage channel with trapezoidal shape with the lower side of 35 cm, upper side of 90 cm, and depth of 40 cm. It is also able to place the dug soil on the top of initial ridges. The prototype of the ditcher was equipped by a pair of soil scrappers. The function of the ditcher is to make the drainage channel, whereas function of the scrapper is to scrap the soils in between the ridges and put it on the top of the ridges. Scrapping mechanism was driven by a front wheel that rolls on the ridge’s profile. The drive force then was transmitted through a transmission shaft to drive the scrapper. The structure of the scrapper ditcher consisted of a frame, a ditcher, and a pair of scrappers. The frame had a triangular shape and equipped with three standardized hitching points. The ditcher had share cutting angle of 70o, 60 cm in cutting width, share intersection angle of 15o, and the concaveness radius of the mold of 65 cm. The construction of the scrapper driver consisted of front wheel (41 cm in diameter), wheel arm (28 cm in length) and the scrapper blade (40 cm x 55 cm in size), scrapper arm (68 cm in length). The dimension of the scrapper ditcher was 173 cm in length, 293 cm in width, and 138 cm in height, and the weight is 435 kg. The modified scrapper ditcher operated successfully. The ditcher produced the expected trapezoidal type drainage channel with a proper size. The test result at Experimental Field of Leuwikopo showed that the length of lower side, upper side and the depth of the ditcher were 39.1 cm, 113.1 cm and 33.1 cm respectively. Whereas, the test result at PG. Jatitujuh showed that the length of lower side, upper side and the depth of the ditcher were 37.9 cm, 100.2 cm and 38.7 cm respectively. The scrapper could scrap the discharged soils and then placed the soils on the ridges. However, there was un-scrapped soil in between the ridges which has 6 cm in height (at Leuwikopo), and 15.8 cm in height (at PG. Jatitujuh). The wheel slip of the tractor, draft, and theoretical field capacity were 37.58%, 2.84 kN and 3.72 ha/hour respectively (at Leuwikopo), and 63.12%, 6.49 kN, and 6.85 ha/hour respectively (at PG Jatitujuh).

Salah satu faktor penentu keberhasilan budidaya tebu adalah sistem drainase yang baik. Got malang merupakan saluran drainase melintang untuk menyalurkan kelebihan air dari barisan tanam tebu. Pembuatan got malang di PG. Jatitujuh dengan menggunakan rotary ditcher menghasilkan bentuk dan dimensi saluran drainase seperti yang diharapkan, namun mempunyai permasalahan pisau yang mudah tumpul dan aus, dan kerusakan pada PTO traktor. Penggunaan kair mata satu lebih disukai, namun saluran yang dihasilkan tidak sempurna dan juring tanaman tertutup oleh buangan tanah yang menumpuk di kedua sisi saluran sehingga menutupi aliran air dari barisan tanam. Penelitian ini bertujuan membuat ditcher drainase yang ditarik oleh traktor roda-4 tanpa menggunakan tenaga PTO traktor untuk menghasilkan saluran drainase berpenampang trapesium dengan lebar dasar 35 cm, lebar atas 90 cm, kedalaman 40 cm dan buangan tanah pada cekungan guludan harus dipindahkan ke punggung guludan.