How to control the planting depth of manual transplanter

The Importance of Planting Hole Depth
In agricultural production, planting hole depth is directly related to crop emergence rate and growth. Too shallow a planting hole may expose roots to air, resulting in insufficient water and nutrient absorption and reduced survival rate. Too deep a planting hole can impair seedling growth and even cause slow growth or deformities. In manual transplanting operations, properly controlling the planting hole depth is crucial for ensuring efficient transplanting and uniform seedling emergence.

Basic Principle of a Manual Transplanter
A manual transplanter, through the operator's push or pull, uses a mechanical mechanism to separate seedlings from a seedling tray from the seedbed and accurately place them in a pre-set planting hole in the soil. Controlling the planting hole depth primarily relies on a combination of mechanical design, adjustment mechanisms, and operation. Generally, the planting hole depth adjustment mechanisms of a manual transplanter include furrow depth adjustment, seedling pusher adjustment, and support wheel height adjustment.

Furrow Depth Adjustment
The furrow mechanism is the part of the manual transplanter that directly contacts the soil; its depth determines the initial planting hole depth. The trenching mechanism typically consists of a blade- or hoe-shaped metal component. Some advanced models allow for variable trenching depth using a screw or latch mechanism. The operator adjusts the trenching mechanism height based on soil type and crop requirements to create a consistent trench depth throughout the process, thereby controlling the initial planting hole depth range.

Adjusting the Seedling Pusher
The seedling pusher is a key component for pushing seedlings from the seedling tray into the soil. The pusher length and push angle directly affect the depth of the seedlings. Some manual transplanters are equipped with pusher height adjustment bolts or slides, allowing the operator to fine-tune the desired planting hole depth. The pusher and trenching mechanism work together to precisely position the seedlings within the trench, ensuring the desired planting hole depth.

Adjusting the Support Wheel Height
Manual transplanters are typically equipped with support wheels or travel wheels to maintain stability and balance. Adjusting the support wheel height not only affects operator comfort but also indirectly affects the planting hole depth. By adjusting the support wheel's contact height with the ground, the machine's forward or backward tilt angle can be adjusted, thereby fine-tuning the trenching depth and seedling insertion depth. Proper support wheel height settings can reduce uneven planting hole depths and ensure uniform planting depth.

Depth Control in Different Soil Conditions
Soil type and moisture significantly influence hole depth control. In clay or moist soils, trenching resistance is high, which may result in shallow holes or push rod rebound. This requires increasing trenching pressure or adjusting the push rod angle. In loose, sandy soils, holes are prone to being too deep. The trenching mechanism should be raised or the push rod stroke shortened. Operators should consider soil conditions and ensure the hole depth is within an appropriate range during adjustment.

Crop Type Depth Adjustment Requirements
Different crops have specific requirements for hole depth. For example, vegetable seedlings generally require shallow planting to facilitate rapid sprout expansion, while rice or tobacco seedlings require deep planting to ensure adequate root contact with the soil. On the manual transplanter, by adjusting the combined furrowing depth, push rod length and support wheel height, it can flexibly adapt to the planting needs of different crops and achieve precise transplanting.