Search

To improve the utilization rate of pineapple leaf and crop straw, and provide technical support for making biodegradable fiber mulch paper through organic cultivation, the process and properties of the degradable fiber mulch paper made from pineapple leaf and rice straw were studied. The degradable fiber mulch paper was prepared as a hybrid composite in which pineapple leaf fiber and rice straw fiber were used as raw materials, and environmentally friendly agents were added. A four-factor five-level quadratic orthogonal rotation central composite design of the response surface method was employed. The beating degree of pineapple leaf fiber, basis weight, addition ratio of pineapple leaf fiber, and wet strength agent content were process parameters; dry tension strength, wet tension strength, and bursting strength were objective functions. The optimal technology parameters of pineapple leaf and rice straw fiber mulch paper were 70 to 90 g/m2 basis weight of pineapple leaf fiber, 17% to 25% addition ratio of pineapple leaf fiber, 55 °SR beating degree, and 1.5% wet strength agent content. According to the tensile strength and bursting strength standards, the degradable fiber mulch paper made from pineapple leaf and rice straw was feasible. The results provide theoretical basis and technical support to use pineapple leaves and rice straw to make degradable mulch paper.

Physical chemical methods were used to treat papermaking white water used to produce plant fiber mulch sheet that contained fine fibers and inorganic fillers as suspended solids. The ordinary chemical oxygen demand (CODCr) was obviously reduced after the papermaking white water was treated by the flocculant. By comparing three different coagulants (aluminum sulfate (Al2(SO4)3), poly-aluminum chloride (PAC), and poly(diallyldimethylammonium chloride) (PDADMAC)) and flocculant (poly-acrylamide copolymer (PAM)) to process papermaking white water, it was found that Al2(SO4)3 had the best coagulation effect and the lowest cost. The best flocculation conditions were 2,733 mg/L of Al2(SO4)3 and 4.52 mg/L of PAM to treat the papermaking white water. Under the best flocculation conditions, the CODCr was less than 300 mg/L. The goal of closed recycling and zero discharge of white water in the production process of plant fiber mulch sheet was realized.

To solve the problems of the damage of weed in paddy field on crop yield and quality, the impact of chemical herbicides on the ecological environment, and the soil pollution caused by plastic film mulching, the field-positioning test was carried out in 2015 to 2017. Taking Daohuaxiang 2 as the test material, three treatments (plant fiber-based degradable film, plastic film, and CK) were setup to investigate the effects of plant fiber-based degradable film on the weed inhibition, warming effect under mulching cultivation, rice yield, rice quality, and economic benefit. The results showed that compared with CK, the plant fiber-based degradable film and plastic film reduced the weed by 85.5% to 87.7% and 78.7% to 81.7%, respectively. Plant fiber-based degradable film mulching cultivation can increase the soil temperature of soil layer 0 to 0.1 m depth. In 2015 to 2017, rice yield with plant fiber-based degradable film increased by 8.71%, 7.53%, and 9.02%, respectively. Plant fiber-based degradable film can significantly reduce the hardness, increase its adhesion, and improve the eating quality of rice. Different films mulching had a certain impact on crop economic benefit. During the developmental stage of the panicle, the plant fiber-based degradable film began to crack, and by the blossom fruit period, the degradation rate reached the grade of 3 or 4. Therefore, the use of plant fiber-based degradable film instead of plastic film can reduce the amount of weed under the membrane and create a more suitable soil temperature, which was conducive to rice yield and quality.

Biodegradable mulching film (BMF) is a promising alternative to petroleum-based plastic mulching film. Thermal conductivity is an important quality factor of BMF that affects the heat transfer between ambient to soil and plant growth. The objective of this research was to enhance the thermal conductivity of fiber film through an environmentally friendly agent and optimized processing conditions. Response surface methodology (RSM) was used to optimize the processing conditions. With optimized process conditions of 70 g/m2 basis weight, 1.5% wet strength agent content, 0.5% neutral sizing agent content, 15% charcoal addition ratio, and 55 &deg, SR beating degree, the films showed satisfactory thermal conductivity (0.0714 W/m&middot, K) and high dry and wet tensile strengths (33.4 and 12.2 N). The addition of charcoal increased the thermal conductivity of the film by 34.31%. This promising result shows the biodegradable fiber film is able to increase soil temperature and meet the required temperature for crop growth.

The present work addresses the optimization of temperature-increasing, environmentally friendly biodegradable film with titanium dioxide and rice straw fiber using response surface methodology (RSM) analysis. The effects of the various process parameters (basis weight, neutral sizing agent, addition ratio of titanium dioxide, wet strength agent, and beating degree) on the dry tensile strength, wet tensile strength, and light-scattering coefficient of the fiber film are reported. The optimal technical parameters of the temperature-increasing film made from titanium dioxide and rice straw fiber included a 64 to 68 g/m2 basis weight, 1.55% to 1.60% wet strength agent, 0.9% neutral sizing agent, 18% addition ratio of titanium dioxide, and 35°SR beating degree. Under this condition, the dry tensile strength, wet tensile strength, and light-scattering coefficient were higher than 30 N, 10 N, and 45 m2/kg, respectively. The film was characterized using Fourier transform infrared (FTIR) spectroscopy. In addition, the resulting film met the requirements of mechanical properties for field mulching and agronomic requirements for crop growth. The results provided a reference for the preparation of fiber film suitable for the temperature required for crop growth.