Rain-fastness and puncture resistance of biodegradable horticultural hydromulches

Authors: DURADO, ANDREW - Montana State University; ARA, ISMAT - Montana State University; BAJWA, DILPREET - Montana State University; GRAMIG, GRETA - North Dakota State University; DEVETTER, LISA - Washington State University; Weyers, Sharon; FORMIGA, ALICE - Oregon State University; GALINATO, SUZETTE - Washington State University; AHMAD, WAQAS - North Dakota State University; WEISS, BENJAMIN - Washington State University; BAJWA, RUTI - Montana State University

Submitted to: Industrial Crops and Products
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/3/2025
Publication Date: 10/15/2025
Citation: Durado, A.D., Ara, I., Bajwa, D.S., Gramig, G., Devetter, L.W., Weyers, S.L., Formiga, A., Galinato, S., Ahmad, W., Weiss, B.D., Bajwa, R.A. 2025. Rain-fastness and puncture resistance of biodegradable horticultural hydromulches. Industrial Crops and Products. https://doi.org/10.1016/j.indcrop.2025.121472.
DOI: https://doi.org/10.1016/j.indcrop.2025.121472

Interpretive Summary: Weed management strategies are vital in horticultural production for promoting crop growth. Strategies such as mulching can control weeds, enhance nutrients, and provide better soil conditions. Traditional low-density polyethylene (LDPE) mulches are effective but pose environmental challenges due to poor recyclability and persistence in the environment. Various formulations of biodegradable hydromulches (HM), composed of cellulose fibers and tackifiers, were evaluated for rain fastness and mechanical resistance to puncture at varying moisture levels to determine suitability as a sustainable alternative to LDPE. The fiber-based formulations tested were made with paper, wood, or a mixture of paper with wood or hemp hurds, and held together with tackifiers, such as guar gum, psyllium husk, or camelina seed meal added at 0%, 2%, 4% or 6% of total dry weight. Rain fastness tests, determined with a simulated rainfall, indicated that HMs of paper only or mixtures with 75% paper tended to resist falling apart better than mixtures of 50% paper to wood or with wood only. Puncture resistance was significantly greater for paper formulations with 4% or 6% guar gum or psyllium husk tackifiers, than most all other formulations tested, but also decreased significantly for all formulations if initial had more moisture. Overall, paper-based HM formulations demonstrated superior performance, with the top five formulations containing paper and varying concentrations of guar gum, psyllium husk, and camelina meal. These findings suggest that paper-based HMs are promising biodegradable alternatives to non-biodegradable LDPE mulch, suitable for organic farming.

Technical Abstract: In horticultural production, mulching is vital for suppressing weeds, optimizing the soil environment, and promoting crop growth. Traditional low-density polyethylene (LDPE) mulch, despite its effectiveness, poses environmental challenges due to poor recyclability and persistence in ecosystems. Biodegradable hydromulches (HM), composed primarily of cellulosic materials and tackifiers, offer a sustainable alternative. This study evaluated various HM formulations to identify those with optimal mechanical strength and moisture resistance. Formulations incorporated fibrous materials, such as paper, wood fiber, hemp hurds, or combinations thereof, blended with tackifiers—guar gum, psyllium husk, or camelina meal at 2%, 4%, or 6% concentrations. Moisture characteristics were assessed for puncture resistance at four moisture levels, 0%, 50%, 75%, and 100% and rainfastness. Puncture resistance was measured as the pressure level at which a flat 13.7 mm dia probe ruptured the formulation. Rainfastness, a measure of the resistance to material loss under simulated rain, was calculated as the ratio of weight of HM before and after rainfastness tests. Results showed HM puncture resistance decreased significantly with increased moisture, dropping below 0.50 MPa at 50% moisture content. Rainfastness tests indicated that paper-based HMs resisted disintegration better than wood fiber-based ones, losing only 4-37% of strength compared to wood fiber formulations. Hemp inclusion decreased strength by 40–70%, depending on the tackifier. Formulations with psyllium husk maintained higher strength than those with camelia meal and guar gum. Paper-based HMs had minimal material loss during simulated rainfall, with a rain fastness index (RFI) of 0.93, superior to wood fiber formulations' RFI of 0.84. Adding hemp increased material loss by 2–4%. Overall, paper-based HM formulations demonstrated superior performance, with the top formulations containing paper and varying concentrations of guar gum, psyllium husk, and camelina meal. These findings suggest that paper-based HMs are a promising biodegradable alternative suitable for organic farming but require further field testing.