Engineering Properties of Some Plug-type Vegetable Seedlings for Development of Automatic Vegetable Transplanter

Transplanting of vegetable seedlings has been referred as a critical and time-consuming activity in vegetable production system. In India, manual transplanting operation of vegetable seedlings is done in most areas due to non-availability of appropriate transplanter, and is drudgery prone. To mechanize this operation, vegetable transplanter needs to be developed considering engineering properties of plug-type seedlings as tomato, brinjal, and cabbage grown in pro-tray. Basic engineering properties of 30-day old seedlings of tomato, brinjal, and cabbage relevant to design of vegetable transplanter were evaluated. The moisture content of whole seedling and root bulb of tomato, brinjal, and cabbage seedlings were 84.3 (± 3.6), 86.7 (± 4.5), and 84.57 (± 3.7)% w.b., respectively. The average respective heights of the seedling were 162.44 (± 19.80), 129.4 (± 16.96), and 114.13 (± 19.98) mm, whereas, canopy major dimensions were (length) 110 ± 15.62, 79.3 ± 16.08, 91.93 ± 14.44 mm, respectively. The coefficient of frictions offered by mild steel were 0.81 (± 0.08), 0.81 (± 0.07), and 0.89 (± 0.04) for tomato, brinjal, and cabbage seedlings, respectively; and adhesion force between pro-tray and seedlings were 1.43 (± 0.40), 0.95 (± 0.22), and 0.41 (± 0.04) N, respectively. The average compression forces of the root bulbs were 6.05 ± 1.53, 5.8 ± 0.56, and 10.26 ± 0.16 N; and average needle penetration forces into root bulbs was 5.18 (± 0.86), 7.83 (± 0.56), and 19.47 (± 0.59) N for tomato, brinjal, and cabbage seedlings, respectively.