A liquid bioplastic formulation for film coating of agronomic seeds

Interest in industrial and domestic applications of biodegradable plastics from renewable sources is increasing, but their use in agriculture is still limited (e.g., mulching films, plant pots, and plant clips). However, a sprayable liquid bioplastic formulation was recently evaluated for application of microbial biocontrol agents to agricultural and horticultural crops. In this study bioplastic formulation has been evaluated for use in film-coating seeds of two agronomic species, corn and canola. Bioplastic seed coating was achieved using procedures and equipment designed for commercial polymer film-coating of tablets. Germination of both species was unaffected by the thin bioplastic coating. Bioplastic coatings containing spores of the plant-growth promoting fungus, Trichoderma harzianum, significantly stimulated the growth of corn and canola seeds. In corn seedlings, shoot and root lengths were 29% and 44% longer, respectively, in seeds coated with T. harzianum-containing bioplastic than in uncoated seeds. Similarly, in canola seedlings shoot and root lengths were 19% and 20% longer, respectively, in seeds coated with T. harzianum-containing bioplastic than in uncoated seeds. In a paper-roll assay, including T. harzianum spores prevented reduced germination caused by a mixture of the insecticide imidacloprid and the fungicide metalaxyl-M in bioplastic seed coatings. The adhesive and plastic properties of bioplastic reduced dust-off from bioplastic-coated seeds by 96% in corn and 99% in canola compared to seeds coated with a commercial polymer.     

不同生物降解膜在新陆早61号上的应用研究

[目的]研究不同生物降解膜在新陆早61号上的应用效果。[方法]开展3种生物降解膜在棉花新陆早61号上的田间比较试验,针对3种生物降解膜的地温、降解膜降解性能和新陆早61号的农艺性状及经济性状进行综合分析,旨在筛选出适合兵团棉花生产利用的降解膜产品。[结果]降解膜的厚度越厚降解越早,厚度越小降解速率越快。3种供试生物降解膜与普通地膜相比延缓了新陆早61号各生育期的生长发育,在出苗期至现蕾期增温效果比普通地膜差;同时植株的生长势减弱,叶面积指数降低,群体收获株数减少,结铃减少,产量不同程度的减少。[结论]3种供试生物降解膜都能降低土壤地膜残留,有效地减少了残膜对土壤的污染。     

生物可降解型自控缓释尿素养分释放规律的研究

以4种生物可降解型自控缓释尿素（CU1、CU2、CU3、CU4）为研究材料,通过静水释放试验模拟研究了4种肥料在常温条件下的养分释放规律,采用静水释放试验研究了不同温度对CU4养分释放的影响以及采用土壤培养的方法研究了不同土壤含水量对CU4养分释放的影响。结果表明,CU1和CU2养分累积释放曲线呈倒＂L＂形,CU3和CU4养分累积释放曲线呈＂S＂形,这与非生物可降解型聚合物包膜尿素养分累积释放曲线相同。4种肥料的初溶出率为0.07%-8.77%,微分溶出率除CU1外,均低于4%,其中CU4初溶出率最低,控释效果最好,约控释85天。升高温度将增大养分释放速率,缩短控释时间,降低土壤含水量能够降低养分释放速率和养分释放总量,但不管是升温还是降低土壤含水量均不改变肥料养分累积释放曲线类型。     

不同生物降解地膜对花生光合特性和产量的影响

为探讨生物降解地膜的控温控水效应及对花生生长发育和产量的影响, 进行了 4种全生物降解地膜、 普通地膜与不覆盖地膜的对比试验。结果表明： 地膜覆盖均优于不覆膜处理。生物降解地膜 Q2降解速度过快, 其他生物降解地膜降解期适宜。生物降解地膜 Q3更利于花生的光合特性和产量的形成, 效果优于普通地膜; Q4 与普通地膜相近, 效果略差于普通地膜; Q1、 Q2 2 种地膜效果差于普通地膜。生物降解地膜降解期适中, 能达到与普通地膜相似的保温保墒效果, 在提高叶绿素含量, 叶片净光合速率, 延缓叶片衰老方面优于普通地膜处理。Q3、 Q4 2种生物降解地膜能满足花生不同生育期对土壤温度、 水分的需要, 前期增温保水, 后期降温增渗, 促进光合作用, 并且可以减少白色污染, 减轻对土壤性质的破坏, 生态效益和经济效益良好, 具有广阔的应用前景。     

不同类型地膜覆盖对土壤水热与葵花生长的影响

通过设置普通塑料地膜、A型生物地膜、B型生物地膜、液体地膜以及无膜覆盖(CK)5个处理,比较分析不同类型地膜覆盖对土壤地温、土壤基质势以及葵花生长和产量的影响。结果表明,葵花生育前期(6—7月)普通塑料地膜和生物地膜覆盖的地温无显著差异,而在生育后期特别是9月份普通塑料地膜处理的土壤表层(0~20 cm)地温明显高于生物地膜覆盖处理,其中A型生物地膜覆盖处理的地温略高于B型生物地膜覆盖处理,而液体地膜覆盖与无膜处理在全生育期地温显著低于普通塑料地膜和生物地膜覆盖处理(p0.05)。生物地膜覆盖处理的保水效应与普通塑料地膜覆盖处理相近,仅在作物生长末期(9月底)生物地膜与普通塑料地膜覆盖处理在0~20 cm土层基质势差异达到显著水平,尽管液体地膜覆盖与无膜处理相比有一定的保水效应,但差异不显著。生物地膜覆盖下葵花株高、叶面积指数以及收获后的叶质量、茎质量、花盘质量和产量与普通塑料地膜覆盖处理均无显著差异,但都显著优于液体地膜覆盖和无膜处理(p0.05)。     

PBAT型全生物降解地膜对南疆马铃薯产量及土壤温湿度与养分的影响

以聚己二酸/对苯二甲酸丁二酯(PBAT)型全生物降解地膜(BMF)为处理、普通PE地膜为对照(CK),采用田间试验,系统分析BMF的降解性能以及对土壤温湿度、养分、盐分、pH和马铃薯产量的影响。结果表明:马铃薯生育期,BMF的降解过程为先出现裂纹,后裂纹逐渐明显,马铃薯成熟期裂解为4 cm×4 cm以下碎片。BMF在6-7月自然降解破损率均较小,为0.4%～4.0%,8月成熟期破损率较大,为15.0%,而同一时期CK未出现降解。BMF在膜下5 cm和15 cm的平均土壤温度分别较CK低1.08℃和0.26℃,而膜下25 cm较CK高0.27℃;膜下5 cm的平均土壤含水率较CK低3.77%,而膜下15 cm和25 cm分别较CK显著低5.64%和14.60%。在0～20 cm和20～40 cm土层,BMF与CK间土壤养分、盐分和pH差异均不显著。BMF处理马铃薯增产2 500.01 kg·hm~(-2),增产率达5.67%,但增产未达到显著水平。PBAT型全生物降解地膜的降解性能良好,对南疆马铃薯产量、土壤温湿度和土壤养分等指标的影响与CK差异不显著。降解地膜代替普通聚乙烯PE地膜应用于南疆马铃薯生产具有可行性。     

有机肥部分替代化肥对旱地地膜冬小麦产量及水肥利用效率的影响

为探求旱地冬小麦全生物降解地膜绿色覆盖栽培条件下有机肥氮替代化肥氮的适宜比例，于2020—2021年在甘肃定西布设大田试验，比较分析了单施化肥（CK）、15%有机肥氮替代化肥氮（OR₁₅）、30%有机肥氮替代化肥氮（OR₃₀）、45%有机肥氮替代化肥氮（OR₄₅）处理下旱地冬小麦干物质积累、籽粒产量、耗水量、水分利用效率、氮素效率等的差异。结果表明，与CK相比，适宜比例的有机肥替代化肥可有效调节冬小麦生长发育，优化干物质积累和耗水过程，提高籽粒产量和水肥利用效率。有机肥替代处理的花前群体干物质积累量均显著低于CK，而OR₁₅和OR₃₀处理的花后群体干物质积累量分别较CK增加了20.22%和5.39%，OR₄₅处理则降低21.84%；与CK相比，OR₁₅处理增产6.15%，OR₃₀和OR₄₅处理分别减产2.87%和10.43%；OR₁₅和OR₃₀处理的水分利用效率较CK提高了7.76%和3.78%，OR₄₅处理降低了1.89%；OR₁₅、OR₃₀和OR₄₅处理的生育期耗水量分别较CK低1.53%、6.43%和8.67%，而花后耗水量分别高7.46%、1.82%和0.80%；相比于CK，适宜比例的有机肥替代化肥主要通过增加小麦穗数和千粒重提高籽粒产量；有机肥替代处理均显著提高了冬小麦氮素利用效率、氮素收获指数和化肥氮偏生产力，且分别平均较CK提高了10.36%、4.46%和42.16%；OR₁₅处理的籽粒氮积累量较CK增加了7.81%，OR₃₀和OR₄₅处理分别降低了8.63%和20.35%。通过综合分析，有机肥氮15%替代化肥氮可作为陇中旱地冬小麦全生物降解地膜绿色覆盖栽培条件下实现小麦稳产增产及提质增效的氮素管理模式。     

Modified atmosphere packaging of fresh produce with a biodegradable laminate of chitosan-cellulose and polycaprolactone

Use of a biodegradable laminate of a chitosan-cellulose and polycaprolactone as a film for modified atmosphere packaging (MAP) of fresh produce was tested. The temperature dependence of O₂, CO₂ and N₂ gas permeability coefficients for the biodegradable laminate was examined. The coefficients increased linearly with increasing temperature in the range 10–25 °C. The coefficients were validated by experiments on MAP with shredded lettuce and shredded cabbage. MAP systems with head lettuce, cut broccoli, whole broccoli, tomatoes, sweet corn and blueberries were designed using the gas permeability coefficients. The gas composition in each biodegradable package including the fresh produce was simulated to be close to the optimal composition. The biodegradable laminate was found suitable as a packaging material for storage of fresh produce.     

Thermal decomposition kinetics of copolymers derived from<Emphasis Type="Italic">p</Emphasis>-dioxanone,L-lactide and poly(ethylene glycol)

The kinetic parameters, including the activation energyE, the reaction ordern, and the pre-exponential factorZ, of the degradation of the copolymers based on the poly(L-lactide) (PLLA) or poly(p-dioxanone-co-L-lactide) (PDO/PLLA) and diol-terminated poly(ethylene glycol) (PEG) segments have been evaluated by the single heating methods of Friedman and Freeman-Carroll. The experimental results showed that copolymers exhibited two degradation steps under nitrogen that can be ascribed to PLLA or PDO/PLLA and PEG segments, respectively. However, copolymers exhibited almost single degradation step in air. Although the values of initial decomposition temperature were scattered, copolymers showed the lower maximum weight loss rate and degradation-activation energy in air than in nitrogen whereas the higher value of temperature at the maximum rate of weight loss was observed in air.     

全生物降解地膜覆盖对河西灌区马铃薯田耕层土温及产量的影响

全生物降解地膜可作为治理农用聚乙烯地膜残留污染的主要措施之一,但由于其生产工艺不同致使降解性能差异较大,导致使用区域范围和作物种类受限,推广使用时需做适合性试验。为明确全生物降解地膜在河西灌区马铃薯栽培应用中能否满足其生育期对热量的需求,为河西灌区马铃薯种植中全生物降解地膜替代聚乙烯地膜及区域农业生产绿色发展提供数据支撑和科学依据。以马铃薯品种大西洋为指示品种,选用聚乙烯地膜和全生物降解地膜进行垄上覆盖栽培,研究了在河西灌区全生物降解地膜覆盖对马铃薯田耕层土壤温度和马铃薯产量的影响。结果表明,与覆盖聚乙烯地膜相比,采用全生物降解地膜覆盖时5、15、25 cm土层土壤日平均温度降低了1.10 ℃,马铃薯折合产量(39 073.50 kg/hm2)增加了13.64%,这表明全生物降解地膜覆盖能够满足马铃薯生育期对热量的需求,可显著增加马铃薯产量。综上,在不改变当地田间管理措施的条件下,在河西灌区马铃薯栽培中可以使用符合或优于国标(GB 35795-2017)要求的全生物降解地膜替代聚乙烯地膜。