Practical test: John Deere CTS 9780i combine harvester For your ‘i’s only… … comes this John Deere practical report, in which profi testers tuck the firm’s CTS 9780i combine into winter wheat and oilseed rape. Our conclusion on last summer’s experience? ‘Mixed’ is the word that best sums up our thoughts, thus reflecting the typically varied views on whether rotary or conventional straw walker designs represent the ultimate crop-separating solution