Paper sheet mulches and methods of making the same

Abstract

The present disclosure provides novel paper sheet mulch products having benefits over prior sheet mulches, which may include brown or recycled fibers, as well as additives, such as opacity, water-resistant, and strength additives, resulting in mulch products with an improved combination of basis weight, stretch, strength, opacity, and / or water-resistance characteristics.

Description

[0001]This application claims priority to U.S. Provisional Patent Application No. 62 / 843,765, filed May 6, 2019, which is hereby incorporated by reference in its entirety.TECHNICAL FIELD[0002]The present disclosure relates to sheet mulches made from paper substrates having benefits over prior sheet mulches, including an improved combination of environmental impact, cost, and performance, as well as methods for manufacturing such paper sheet mulches.BACKGROUND[0003]Mulch is a layer of material applied to the surface of soil for the purpose of improving soil productivity and resultant crop yield. Mulch may be applied either in the form of loose material, such as grass clippings, leaves, bark, wood chips and the like, or in the form of a more structured material, such as a sheet. Benefits of mulches may include one or more of increased soil temperature (which can allow earlier planting and earlier maturation of crops), deterred weed growth (which can reduce mechanical weeding that can ...

AI Technical Summary

Benefits of technology

The present inventors have developed better paper sheet mulches that are stronger, have more opacity, and are more resistant to water. These improvements make them better suited for use in agricultural settings. The paper sheet mulches may contain recycled or brown fibers, and may also have additives to make them opaque, water-resistant, or stronger. Additionally, they may have increased stretch to withstand physical stress during use.

Problems solved by technology

While synthetic sheet mulches have proven effective for improving crop yield, their use also has a number of negative attributes and costs.

Synthetic sheet mulches require not only installation of the sheet, but removal of the sheet, which is time consuming and typically involves manual labor, resulting in significant cost to the farmer.

The removed synthetic sheet mulch must also be disposed of, which has presented a large environmental problem.

The synthetic sheets cannot simply be tilled into the soil, as they will cause contamination and year-to-year accumulation.

Synthetic sheet mulches also cannot be burned, as burning releases harmful pollutants.

Recycling is typically also not feasible with the high levels of contaminants (e.g., soil, fertilizer, vegetation) and the photodegraded nature of the sheet.

Landfilling has thus become the primary accepted practice for disposing of synthetic sheet mulches, but this practice also has significant environmental and economic costs.

Introduced in the 1980's, many are not suited to organic farming because they are not entirely composed of constituents derived from natural sources.

There is also concern that these materials do not break down completely, leading to accumulation of plastic fragments in the soil and, ultimately, in the oceans.

These films are also costly, often 2-3 times the cost of polyethylene-based sheet mulches.

If the paper degrades too quickly, it can render the sheet useless.

To date, existing paper sheet mulches have been found to have an unacceptable combination of physical properties, for example the combination of basis weight, strength, and stretch needed to ensure a cost effective product that can withstand the required physical abuse.

Prior paper sheet mulches have also been found to have inferior soil temperature, moisture retention, weed control, whether resistance, and / or crop yield properties, particularly compared to synthetic nonbiodegradable sheet mulches.

Prior paper mulches have also been found to be costly compared to even biodegradable plastic mulch alternatives.