Plans for a Machine to Collect Plastic Mulch

The use of plastic mulch is a common practice for strawberry and vegetable growers, but there are two major problems with plastic mulch: it is expensive to install and at some point it has to be removed from the field.

Several machines are available that help simplify the removal of the mulch. After the plastic is loosened and lifted, some growers pick up the plastic by hand; however, there are several machines available to pick up the plastic. The most common design has a powered spool to roll up the plastic. In most cases, a worker has to tie the strip of plastic to the spool at the beginning of the row and then the plastic can be rolled up. A major problem with this type of pickup device is that as the spool fills, its diameter increases and thus the peripheral speed of the plastic increases. As the spool fills, either the tractor ground speed must constantly increase or the spool rotational speed must constantly decrease. This problem is addressed in different ways on different models of mulch collectors. Some use a belt drive to the spool and allow the belt to slip to maintain constant tension on the plastic. Others have a variable-speed valve in the hydraulic line to the spool motor that must be manually adjusted (constantly) by an operator riding on the machine. A design developed by the LSU AgCenter senses the tension on the plastic and automatically adjusts spool speed to provide relatively uniform torque loading on the spool.

Drawings are available to use in building a mulch collector based on the LSU AgCenter design. The drawings show a version that rolls the used plastic around four bars, then when one end is removed, the bars collapse to allow the roll of plastic to be removed. The design can be modified to allow inserting a fiber roll (saved from installing the new plastic) to serve as a core and then just discarding the fiber roll with the roll of used plastic.

Basic Frame

Spool Driver

Spool – Left End

Spool Latch Arm

Spool – Right End

Spool Shaft

Spool Detail

Swing Arm

Bearing Mounting Plate - Top

Spool Tube

List of Materials(other than basic steel)

Quantity Description

1 Hydraulic motor, 9.9 in3/rev

1 Adjustable flow control valve

1 Check valve

2 ½ x 48” hydraulic hose

2 ½ X 72” hydraulic hose

2 40B16 sprocket with 1.00” bore

10 ft #40 roller chain

1 #40 roller chain connecting link

1 #40 roller chain offset link

2 1.00” pillow block bearing

1 1.00” flange bearing