Biodegradable plastic mulches: performance, degradation, and impacts on agroecosystems

View the project final report

• 2017 annual report

Commodities

• Vegetables: cucurbits, peppers, sweet corn

Practices

• Education and Training: demonstration, workshop
• Production Systems: general crop production
• Soil Management: soil analysis, soil quality/health

The use of polyethylene mulch in crop production is a standard practice among many specialty crop growers, but its limited disposal options have been a major problem.  Removal and disposal of polyethylene mulch is labor intensive and estimated to cost $250 to $584 ha-1. Sometimes, bailing equipment and disposal facilities are not readily available, causing some producers to stockpile or burn polyethylene mulches which can cause severe harm to the environment. This project seeks to improve the productivity and environmental sustainability of specialty crop production by evaluating biodegradable plastic mulch as alternative to polyethylene mulch. We will (a) evaluate the performance of different biodegradable plastic mulches, and (b) assess their potential effects on agroecosystems. In addition, we will develop a model that could be used to predict soil water and heat flow, as well as crop growth and productivity under biodegradable mulch production systems at any location. The performance of four biodegradable plastic mulches will be tested under pie pumpkin (Cucurbita pepo) production at two locations (Knoxville, TN and Mt Vernon, WA). Paper mulch, polyethylene mulch, and no-mulch treatments will also be included to serve as control. We will perform Nano-scale assessment to determine whether the biodegradable plastic mulches undergo complete degradation. We will work closely with several producers throughout the project to get their input, as well as share with them the findings of the project. We will also organize field tours and a workshop that will train attendees on how to amend readily available crop residues for on-farm composting. Identifying biodegradable plastic mulches that can degrade in soil or in compost without adverse impact on soil quality will be a more sustainable practice with enormous production, economic, and environmental benefits for specialty crop production worldwide. Its adoption will alleviate disposal costs, sustain crop production, and eliminate the accumulation of huge amounts of plastic wastes that exerts negative environmental impacts. 

Overall goal of project is to improve the productivity and environmental sustainability of specialty crop production. The specific objectives are:

Objective 1: Evaluate the performance of biodegradable plastic mulches

Hypothesis: Biodegradable plastic mulch will maintain suitable microclimate and sustain crop growth and productivity comparable to polyethylene mulch.

Sub-objectives:

(1a) Evaluate crop productivity under different biodegradable plastic mulches.

(1b) Measure soil water and heat flow dynamics under different biodegradable plastic mulches.

 (1c) Use results in sub-objectives (1a) and (1b) to develop a model that can be used to predict soil water and heat flow dynamics, as well as the performance of biodegradable plastic mulches at various locations.

Objective 2: Determine the effects of biodegradable plastic mulches on agroecosystems

Hypothesis: The use of biodegradable plastic mulch will have no adverse impact on soil quality and ground water.

Sub-objectives:

(2a) Determine the effects of biodegradable plastic mulches on soil quality.

(2b) Determine whether biodegradable plastic mulches will cause leaching of byproducts that could pollute ground water.

Objective 3: Evaluate the degradation of biodegradable plastic mulches

Hypothesis: Biodegradable plastic mulches will undergo complete biodegradation in compost or in soil regardless of location.

Sub-objectives:

(3a) Evaluate the degradation of biodegradable plastic mulches under different environmental conditions in soils.

(3b) Evaluate the degradation of biodegradable plastic mulches in compost.

Objective 4: Engage and educate producers

Sub-objectives:

(4a) Organize field tours and a workshop.

(4b) Encourage producer adoption of recommendations emerging from the findings of this project