The Ability of Plant Compost Leachates to Control Black Mold (Aspergillus niger) and to Induce the Accumulation of Antifungal Compounds in Onion Following Seed Treatment

Onion seeds treated with leachates of composts prepared from alfalfa and sunflower stalks, at the dosages of 10% and 20% respectively, were inoculated with Aspergillus niger van Tieghem, causal agent of onion black mold disease. The ability of the leachates to induce the production of antifungal compounds and to control black mold were tested at seedling and set stages. Leachates from both composts were able to reduce disease incidence in sets, but not disease severity in onion seedlings. Extracts from treated seedlings and sets were fractionated by thin layer chromatography for their content of antifungal compounds. There were no significant differences between the fractions of alfalfa and sunflower compost leachates in the inhibition of the mycelium growth of A. niger, with the exception of one fraction. The presence of fluorescent pseudomonads and Pantoae agglomerans [synonym: Erwinia herbicola (Löhnis)] bacteria was determined in both leachates. The population of P. agglomerans was higher in the sunflower compost leachate compared to the alfalfa leachate. The tested strains of both bacteria were able to inhibit mycelium growth of the fungal pathogen in agar tests. This study suggests the possible role of beneficial bacteria in the induction of antifungal compounds in onion against A. niger during seedling and set stages.     

基于环境微生物资源库快速构建易腐垃圾高效堆肥复合菌剂

【目的】针对易腐垃圾成分快速构建一种高效堆肥复合菌剂。【方法】研究以"中国科学院战略生物资源服务网络计划"支持建设的微生物资源库为基础,根据菌株产酶活功能信息,针对易腐垃圾有机成分定向挑选出高产酶(蛋白酶、淀粉酶、纤维素酶、木质素酶、脂肪酶)菌株,通过测定菌株间拮抗作用,构建了一种高效堆肥复合菌剂CM菌剂。进行了菌剂发酵条件优化和易腐垃圾堆肥应用研究。【结果】CM菌剂最适发酵条件为接种7%的种子液于红糖培养基中,30°C下培养48h,此时菌剂产生蛋白酶、淀粉酶、纤维素酶、木质素酶、脂肪酶酶活分别为181.76、52.92、1.57、12.81、9.94 U/mL。堆肥结果表明CM菌剂堆肥产品pH、含水率、有机质含量均满足生物有机肥标准(NY884-2012)。CM菌剂堆肥过程中最高温度为63.5°C,高温期9–12 d,30 d后含水率为28.7%,有机质降解率为30.4%,C/N为8.93,与商品菌剂BM相比堆肥效果更好,可使堆体高温期延长4–7d、含水率降低3.8%,可加快易腐垃圾中有机质降解,降解率提升6.2%,并具有更强的固氮能力,缩短腐熟时间,提升堆肥产品品质。【结论】基于环境微生物资源库功能信息构建堆肥复合菌剂是一种快速有效的菌剂构建方法。     

Isolation and characterization of thermophilic methanogenic bacteria from mushroom compost

Abstract During the first stage of the preparation of mushroom compost oxygen is believed to be readily available. However we measured methane in the evoking air above the compost piles and were able to isolate thermophilic methanogenic bacteria from this compost. The isolates grow only on H₂ and CO₂ as energy and carbon source and do not require complex factors for growth. On the basis of nutritional and morphological characteristics these methanogens were identified as strains of Methanobacterium thermoautotrophicum .     

Biocontained Carcass Composting for Control of Infectious Disease Outbreak in Livestock

Intensive livestock production systems are particularly vulnerable to natural or intentional (bioterrorist) infectious disease outbreaks. Large numbers of animals housed within a confined area enables rapid dissemination of most infectious agents throughout a herd. Rapid containment is key to controlling any infectious disease outbreak, thus depopulation is often undertaken to prevent spread of a pathogen to the larger livestock population. In that circumstance, a large number of livestock carcasses and contaminated manure are generated that require rapid disposal.Composting lends itself as a rapid-response disposal method for infected carcasses as well as manure and soil that may harbor infectious agents. We designed a bio-contained mortality composting procedure and tested its efficacy for bovine tissue degradation and microbial deactivation. We used materials available on-farm or purchasable from local farm supply stores in order that the system can be implemented at the site of a disease outbreak. In this study, temperatures exceeded 55°C for more than one month and infectious agents implanted in beef cattle carcasses and manure were inactivated within 14 days of composting. After 147 days, carcasses were almost completely degraded. The few long bones remaining were further degraded with an additional composting cycle in open windrows and the final mature compost was suitable for land application. Duplicate compost structures (final dimensions 25 m x 5 m x 2.4 m; L x W x H) were constructed using barley straw bales and lined with heavy black silage plastic sheeting. Each was loaded with loose straw, carcasses and manure totaling ~95,000 kg. A 40-cm base layer of loose barley straw was placed in each bunker, onto which were placed 16 feedlot cattle mortalities (average weight 343 kg) aligned transversely at a spacing of approximately 0.5 m. For passive aeration, lengths of flexible, perforated plastic drainage tubing (15 cm diameter) were placed between adjacent carcasses, extending vertically along both inside walls, and with the ends passed though the plastic to the exterior. The carcasses were overlaid with moist aerated feedlot manure (~1.6 m deep) to the top of the bunker. Plastic was folded over the top and sealed with tape to establish a containment barrier and eight aeration vents (50 x 50 x 15 cm) were placed on the top of each structure to promote passive aeration. After 147 days, losses of volume and mass of composted materials averaged 39.8% and 23.7%, respectively, in each structure.     

淋洗后生活垃圾堆肥建植高羊茅草坪生理生态响应

以不同淋洗方式处理后的生活垃圾堆肥为基质进行草坪植物培植,研究了高羊茅的生理生态响应。结果表明,淋洗处理堆肥中高羊茅的发芽率及株高等生长指标均优于未淋洗的原堆肥对照组,其中水肥淋洗比例为1∶1的处理中,高羊茅的最大发芽率比对照提高89.6%。通过对超氧化物歧化酶（SOD）、过氧化物酶（POD）、过氧化氢酶（CAT）3种保护酶的活性及脯氨酸和丙二醛（MDA）含量等指标的测定可以看出,经淋洗处理后的堆肥基质对草坪植物的胁迫程度均小于原堆肥,更有利于草坪植物的正常生长。综合高羊茅生长指标及生理指标来考虑,堆肥处理的最佳淋洗比例为水∶堆肥的质量比为2∶1。     

畜禽粪便堆肥过程中氮素的损失与控制

堆肥是实现畜禽粪便处理及资源化利用的有效途径,然而畜禽粪便堆肥过程中氮素损失较严重,对氮素损失与控制的研究可为有效控制氮素损失提供理论基础和实践参考.本文简述了畜禽粪便堆肥过程中氮素转化及主要损失途径,总结了影响堆肥氮素损失的主要因素(包括堆肥物料初始特性、堆肥环境参数和堆肥工艺条件),并综述了氮素损失控制措施(调节C、N代谢,改变氮素形态,添加NH₃吸附剂和调节通风与控温措施)的研究进展,此外,对未来的研究方向进行了展望.     

Effects of spawn,supplement and phase II compost additions and time of re-casing second break compost on mushroom (Agaricus bisporus) yield and biological efficiency

Three cropping experiments (0710, 0803 and 0805) were conducted to determine the effect of adding spawn, various levels of delayed release nutrient, and phase II compost to 2nd break mushroom compost (2BkC) on mushroom yield and biological efficiency (BE). We also investigated the effect of delaying time of re-casing non-supplemented and supplemented 2BkC on mushroom yields and BEs. The addition of 14.6% spawn to nutrient-supplemented 2BkC (w.w./d.w) increased yield by 11.1% over the control (no spawn) but did not affect BE. The addition of delayed release supplements to 2BkC increased maximum yields by 29–54%, depending on the treatment. Substitution of 15% phase II compost in 2BkC (15/85) did not significantly affect mushroom yields. However, use of 15% phase II compost in 2BkC increased the response of the mixture to delayed release supplement. Yield response to increasing levels of supplement was greater in the 15/85 mixture compared to 100% 2BkC. Yields also increased as time of re-casing was delayed up to 10 days. Mushroom yields increased approximately 2.1% for each day re-casing was delayed. Overall yields were generally higher from commercial 2BkC compared to 2BkC originating from the Penn State Mushroom Research Center (MRC) probably due to nitrogen (N) content of the 2BkC. Nitrogen content in commercial 2BkC (Crop 0805) was 3% while N content in 2BkC from Crops 0710 and 0803 was 2.2% and 2.1%, respectively. By optimizing supplement levels and adding 15% phase II compost to commercial 2BkC, or by delaying casing by 5–10 days, it was possible to obtain BEs that were equivalent to supplemented phase II compost.     

Purification and Properties of Extracellular Carboxyl Proteases of Acid-tolerant Bacteria,Isolated from Compost

Four strains of acid-tolerant and protein-using bacteria were isolated from compost. Two of them, Gram-negative strains MB8 and MB11, were identified as a new genus close to Stenotrophomonas species MB8 and Burkholderia species MB11, respectively. Both bacteria produced extracellular carboxyl proteases (CP) in acid-casein-starch medium. The enzymes, termed CP MB8 and CP MB11, purified through ion exchange and gel filtration chromatographies had molecular weights of 61,000 (CP MB8) and 36,000 (CP MB11) as estimated by SDS-PAGE, and showed optimum activities with hemoglobin as a substrate at pH 3.5 (CP MB8) and pH 3.7 (CP MB11) at 55°C. Both of the enzymes were not inhibited by pepstatin, DAN, or EPNP. These results suggest that both enzymes are members of the pepstatin-insensitive carboxyl proteinase family (EC 3.4.23.33), except for a larger molecular weight of the CP MB8 enzyme.     

Compost tea as soil drench: an alternative approach to control bacterial wilt in brinjal

An experiment was conducted in the field laboratory, Department of Plant Pathology, Bangladesh Agricultural University, Mymensingh, to evaluate the efficacy of compost tea and poultry litter extract along with their economic feasibility of their usage in controlling bacterial wilt of brinjal under natural incidence condition. A significant variation was observed among the treatments on the incidence and severity of bacterial wilt in brinjal. The results showed that the lowest wilt incidence was recorded in T₂ (Compost tea as soil drenching), T₅ (Poultry litter as soil application) and T₆ (IPM Lab Biopesticide as soil application) while the highest wilt incidence was recorded in control treatment in both counting periods. Similar trend regarding the performance of these treatments was observed on the bacterial wilt severity of brinjal. The effects of compost tea and poultry litter extract on the growth and yield parameters of eggplant were observed to be significant. The results revealed that plant height, number of branches per plant, number of fruits per plant and fruit yield per ha were recorded as maximum in T₂ (Compost tea as soil drenching), followed by T₅ (Poultry litter as soil application) and T₆ (IPM Lab Biopesticide as soil application), while the minimum plant height, number of branches per plant, number of fruits per plant and fruit yield were recorded in control treatment (T₁). The other treatments showed significant effect in increasing all the growth and yield parameters of brinjal as compared to control. Benefit cost analyses (BCR) showed that T₆ (IPM Lab Biopesticide as soil application) resulted in the highest BCR (99.21) as compared to control, followed by T₇ (BAU-Biofungicide as foliar spray) and T₂ (Compost tea as soil drenching) with BCR 35.7 and 19.5, respectively. The results indicated that an investment of Tk. 1.00 may lead to a profit up to Tk. 99.21 by soil application of IPM Lab Biopesticide which gave the maximum profit in the present study. T₇ (BAU-Biofungicide as foliar spray) followed T₂ (Compost tea as soil drenching) where the investment Tk. 1.00 returned a profit of Tk. 35.70 and Tk. 19.5, respectively. Soil drenching of compost tea showed comparatively lower BCR but the highest percent increase of gross margin was obtained when compost tea was applied as soil drench (T₂). Therefore, it may be concluded that soil drenching of compost tea may be an alternative approach to control bacterial wilt of brinjal along with other possible organic amendments.     

Dynamic Changes in Bacterial Communities During Compost and Earthworm Treatment of Low-Grade Potassium Ore

Both composting and earthworm treatment can degrade potassium rock powders and bacteria play a key role during the bio-processings. To understand the dominant bacteria and bacterial profile in biological conversion of the ore including compost and earthworm treatment, the bacterial communities in the compost were studied by using the method of denaturing gradient gel electrophoresis (DGGE) after ore powder was co-composted with organic wastes and then treated with earthworms. Results showed bacterial community structure changed very quickly during the early stages of solid-state fermentation, but relatively stable in the later stages of fermentation and during earthworm treatment. The dominant species of bacteria largely varied in the earlier stage of composting, but they were stable in the latter stage and during earthworm treatment. Two classes of bacteria, represented by band 12 (likely Alteromonas) and band 14 (likely Firmicutes) in DGGE profile, were found to be dominant species over the entire solid-state fermentation period. No special dominant bacterial species appeared during earthworm treatment. Phylogenetic studies of the bacteria based on 16S rRNA sequences indicate that major 13 bands came from phyla Proteobacteria and Firmicutes, suggesting that bacteria in these phyla played an important role during the compost treatment.