Fabrication of multi-functional biodegradable liquid mulch utilizing xyloglucan derived from tamarind waste for agricultural application.

Biodegradable liquid mulch is considered a promising alternative to plastic mulch for sustainable agriculture. This work proposed a xyloglucan-based liquid mulch with multi-function using a combination of chemical modification and blending methods. The esterification product of tamarind xyloglucan (TXG) from forestry wastes was synthesized with benzoic anhydride (BA). The effect of esterification modification was investigated, and BA-TXG was utilized as a film-forming and sand-fixation agent. The rheological properties, thermal stability, and hydrophobicity were improved following esterification. Additionally, waterborne polyurethane and urea were incorporated into the mulch to enhance its mechanical strength (23.28 MPa, 80.71 %), and homogeneity, as well as improve its nutritive properties. The xyloglucan-based liquid mulch has excellent UV protection, a high haze value (approximately 90 %), and retains water at a rate of 80.45 %. SEM and immersion experiment showed the effect of xyloglucan-based liquid mulch on sustainable sand-fixation. Moreover, the liquid mulch treatment demonstrated an impressive germination rate of 83.8 % and degradation rate of 51.59 % (60 days). The modified polysaccharide film increases stability and slows down the degradation rate. Tamarind xyloglucan-based liquid mulch exhibits powerful and diverse optical properties as well as sand fixation functions, indicating their great potential in sustainable agriculture as an alternative to plastic mulch.

Effects of Biodegradation of Corn-Starch-Sodium-Alginate-Based Liquid Mulch Film on Soil Microbial Functions.

In response to the problems of the poor degradability and mechanical properties of liquid mulch, natural non-toxic polymer compound corn starch and sodium alginate were used to prepare fully biodegradable liquid mulch. The preparation conditions of the mulch were optimized, and the mechanical properties of the mulch and the changes in the microbial community in soil with the mulch degradation were analyzed. The corn-starch-sodium-alginate-based liquid mulch film had an optimum performance at a tensile strength of 0.145 MPa and an elongation at a break of 16.05%, which was attained by adding 33.33% sodium alginate, 50% glycerol 22 and 4% citric acid to corn starch after moist heat modification. Fourier transform infrared spectroscopy analysis showed that the -COOH in sodium alginate could interact with the -OH in starch and glycerol through hydrogen bonding, thus, resulting in a denser structure and better mechanical properties of the liquid mulch as a non-crystalline material. The soil burial degradation study of mulch revealed that corn-starch-sodium-alginate-based liquid mulch degraded completely at 25 days macroscopically, and mulch degradation increased soil organic matter content. Microbial kinetic analysis showed that the abundance and diversity of the bacterial community decreased with the degradation of the mulch, which was conducive to the optimization of the bacterial community structure and function. Arthrobacter of the class Actinomycetes became the dominant microorganism, and its abundance increased by 16.48-times at 14 days of mulch degradation compared with that before degradation, and Acidophilus phylum (14 days) decreased by 99.33%. The abundance of fungal communities was elevated in relation to the main functional microorganisms involved in liquid mulch degradation, with Alternaria and Cladosporium of the Ascomycete phylum Zygomycetes being the most active at the early stage of mulch degradation (7 days), and the relative abundance of Blastocystis was significantly elevated at the late stage of mulch degradation (14 days), which increased by 13.32%. This study provides important support for the green and sustainable development of modern agriculture.