Potato absorption and phytoavailability of Cd,Ni, Cu,Zn and Pb in sierozem soils amended with municipal sludge compost

Effects of sludge utilization on the mobility and phytoavailability of heavy metals in soil-plant systems have attracted broad attention in recent years. In this study, we analyzed the effects of municipal sludge compost(MSC) on the solubility and plant uptake of Cd, Ni, Cu, Zn and Pb in a soil-potato system to explore the mobility, potato plant uptake and enrichment of these five heavy metals in sierozem soils amended with MSC through a potato cultivation trial in Lanzhou University of China in 2014. Ridge regression analysis was conducted to investigate the phytoavailability of heavy metals in amended soils. Furthermore, CaCl_2, CH_3 COONH_4, CH_3COOH, diethylene triamine pentacetic acid(DTPA) and ethylene diamine tetraacetic acid(EDTA) were used to extract the labile fraction of heavy metals from the amended soils. The results show that the MSC could not only improve the fertility but also increase the dissolved organic carbon(DOC) content of sierozem soils. The total concentrations and labile fraction proportions of heavy metals increase with increasing MSC percentage in sierozem soils. In amended soils, Cd has the highest solubility and mobility while Ni has the lowest solubility and mobility among the five heavy metals. The MSC increases the concentrations of heavy metals in the root, stem, peel and tuber of the potato plant, with the concentrations being much higher in the stem and root than in the peel and tuber. Among the five heavy metals, the bioconcentration factor value of Cd is the highest, while that of Ni is the lowest. The complexing agent(DTPA and EDTA) extractable fractions of heavy metals are the highest in terms of phytoavailability. Soil properties(including organic matter, p H and DOC) have important impacts on the phytoavailability of heavy metals. Our results suggest that in soil-potato systems, although the MSC may improve soil fertility, it can also increase the risk of soils exposed to heavy metals.     

磷酸铵镁堆肥产品养分释放特性及其肥效研究

为了研究磷酸铵镁堆肥产品的氮磷养分释放特性及其肥效,分别采用土柱淋溶方法及盆栽试验研究了磷酸铵镁堆肥(MAPC)产品的氮磷养分释放特性及对油菜的肥效,并与普通化肥(CCH)、普通堆肥(CCO)、磷酸铵镁肥(MAP)3种肥料进行对比。结果表明:在整个淋溶过程中,CCH和MAPC处理淋溶液的总氮及总磷浓度均较其他处理高;MAP肥具有缓释性,且堆肥对其养分释放具有促进作用;CCO处理的养分释放最慢。在最后一次淋洗(即第5次)后,总氮及总磷养分浓度排序均为:CCHMAPCMAPCCO。盆栽试验18 d后油菜快速生长,且与对照(不施肥)处理相比,MAP和MAPC处理能显著提高油菜的株高及生物量。在45 d盆栽试验结束时,CCH、CCO、MAP和MAPC处理的生物量分别是对照处理的14.8、4.8、20.5倍和16.0倍。MAP处理能显著提高油菜的养分含量,TN和TP含量分别比对照提高了2.24 g·kg~(-1)和1.54 g·kg~(-1)。研究表明,4种肥料均可改善油菜的生长发育情况,且MAP和MAPC的肥效优于CCH和CCO,在堆肥中利用鸟粪石结晶原理可固定部分氮磷元素,提高堆肥产品肥效。     

Lantana camara——an Ecological Bioindicator Plant for Decontamination of Pb-Impaired Soil Under Organic Waste-Supplemented Scenarios

Heavy metal extraction and processing from ores releases elements into the environment. Soil, being an "unfortunate" sink, has its bionomics impaired and affected by metal pollution. Metals sneak into the food chain and pose risk to humans and other edaphicdependent organisms. For decontamination, the use of an ecosystem-friendly approach involving plants is known as phytoremediation.In this study, different lead(Pb) concentrations(80, 40, 20, and 10 mg kg~(-1)) were used to contaminate a well-characterized soil,(un)supplemented with organic waste empty fruit bunch(EFB) or spent mushroom compost(SMC), with non-edible plant—Lantana camara. Lead removal by L. camara ranged from 45.51% to 88.03% for supplemented soil, and from 23.7% to 57.8% for unsupplemented soil(P 0.05). The EFB-supplemented and L. camara-remediated soil showed the highest counts of heavy metal-resistant bacteria(HMRB)(79.67 × 10~6–56.0 × 10~6 colony forming units(CFU) g~(-1) soil), followed by SMC-supplemented and L. camara-remediated soil(63.33 × 10~6–39.0 × 10~6 CFU g~(-1) soil). Aerial metal uptake ranged from 32.08 ± 0.8 to 5.03 ± 0.08 mg kg~(-1) dry weight, and the bioaccumulation factor ranged from 0.401 to 0.643(P 0.05). Half-lives(t_(1/2)) of Pb were 7.24–2.26 d in supplemented soil,18.39–11.83 d in unsupplemented soil, and 123.75–38.72 d in the soil without plants and organic waste. Freundlich isotherms showed that the intensity of metal absorption(n) ranged from 2.44 to 2.51 for supplemented soil, with regression coefficients of determination(R~2) between 0.901 2 and 0.984 0. The computed free-energy change(?G) for Pb absorption ranged from -5.01 to 0.49 kJ mol~(-1) K~(-1) for EFB-supplemented soil and -3.93 to 0.49 k J mol~(-1) K~(-1) for SMC-supplemented soil.     

智能型规模化膜覆盖好氧堆肥系统设计与试验

设计了一种适用于规模化生产的节能环保智能型膜覆盖好氧堆肥系统,主要包括总控系统、风控系统、传感系统和覆膜系统。结合上述各系统的功能性需求,进行了系统整体性设计、功能模块独立设计选型,该系统可实现堆肥关键参数的高精度实时监测、通风供氧的灵活智能反馈控制、多设备无线通讯等功能。利用该系统进行规模化膜覆盖好氧堆肥性能试验,研究结果表明:整个堆肥过程高温时段满足粪便无害化处理需求,堆体氧浓度维持在适宜水平,覆膜工艺下可确保堆体发酵状况良好。从所监测的流量、频率、温度、压力、氧浓度等多元参数和总体性能来看,与传统技术模式相比,该系统智能化程度显著提升,生产能耗和气体产排显著降低。     

The positive relationship between soil quality and crop production: A case study on the effect of farm compost application

In order to ensure sustainable agriculture, and for evaluating the effects of management practices on soil processes, tools for assessing soil quality are required. The development and use of a multiparameter index, which includes a wide range of soil properties, have been tested and found useful by several studies. However, soil quality measurements are ‘stand-alone’ tools unless they are either linked to important soil functions, used to characterize (agro)ecosystems or used to predict sustainability or productivity. In our study, the relationship between crop production and soil quality was assessed in a six year old field experiment studying the effect of farm compost (FC) amendment in a crop rotation of potato, fodder beet, forage maize and Brussels sprouts. To justify the hypothesis that repeated FC amendment results in both improved soil quality and consequently higher crop yields, a wide range of chemical, biological and physical soil properties were measured and integrated into a soil quality index (SQI). Next, crop yields were used as a functional goal to verify the causal relationship between SQI and crop production. Our results showed that there were significant changes in chemical, physical and biological soil quality as a result of repeated FC amendment. This was evidenced for example by a remarkable increase in both soil organic carbon (SOC) and total N content. Microbial biomass, the relative amount of bacterivorous nematodes and earthworm number were significantly increased as well and, together with SOC and total N, indicated as the dominant factors in assessing soil quality. The integration of these key indicators into the SQI revealed higher SQI values when FC was applied. In addition, crop yields were increased in all FC treated plots by which SOC was pointed out as the most important indicator influencing crop production. Finally, a causal relationship was observed between soil quality and the yield of potato and fodder beet. We conclude that our SQI may be a promising and useful tool to compare different (soil) management practices in relation to a strategic, regional goal, e.g., sustainable high yields. Before generalizing, we recommend a thorough validation of our SQI in other long-term field experiments.     

金针菇松杉木屑菌糠栽培猴头菇的技术研究

为降低猴头菇生产成本和解决松杉木屑工厂化栽培金针菇菌糠利用问题,研究了金针菇菌糠营养成分和不同配方对猴头菇产量及经济效益的影响。结果显示:金针菇菌糠含有9.8%粗蛋白、32.3%粗纤维、1.2%粗脂肪、17.9%木质素和7.7%灰分;筛选出配方2是最佳的配方,比例分别为金针菇菌糠38%、棉籽壳20%、玉米芯30%、麸皮10%、碳酸钙2%,其产量和利润分别比对照组、配方1、配方3和配方4提高了9.67%、25.00%、6.12%、8.40%和115.91%、48.44%、46.15%、25.00%。为金针菇菌糠用于猴头菇大面积栽培提供了科学依据。     

Ryegrass yield and nutrient status after biochar application in two Mediterranean soils

This study was conducted to evaluate whether biochar, produced by pyrolysis at 300°C from rice husk and grape pomace (GP), affects plant growth, P uptake and nutrient status. A 3-month period of ryegrass (Lolium perenne L.) cultivation was studied on two Mediterranean agricultural soils. Treatments comprised control soils amended only with compost or biochar, and combinations of biochar plus compost, with the addition of all nutrients but P (FNoP) or without any fertilization at all (NoF). Application of both types of biochar or/with compost, in the presence of inorganic fertilization except P, significantly increased (P < 0.05) dry matter yield of ryegrass (58.9–77.6%), compared with control, in sandy loam soil, although no statistically significant increase was observed in loam soil. GP biochar and GP biochar plus compost amended loam soil harvests gave higher P uptake than control, in the presence of inorganic fertilization except P, whereas in sandy loam soil, a statistical increase was recorded only in the last harvest. In addition, Mn and Fe uptake increased with the addition of the amendments in both soils, while Ca increased only in the alkaline loam soil. Biochar addition could enhance ryegrass yield and P uptake, although inorganic fertilization along with soil condition should receive special attention.     

Effects of compost amended lead–arsenate contaminated soils on total and inorganic arsenic concentrations in rice

Rice (Oryza sativa L.), a staple crop for over 50% of the world's population, is also a source of dietary arsenic (As) because of it's efficiencyat accumulating As. Lead–arsenate pesticide was used in agriculture, these soils potentially may be used for rice production. The objective of this study was to determine the effects of compost on total and inorganic As concentrations in rice grown on lead–arsenate contaminated soils. Three lead–arsenatesoils were amended with 10% by weight of compost and planted with rice under flooded and non-flooded conditions. Rice grain yieldwas higher with compost but not flooding. Flooding significantly increased total and inorganic As concentrations. In most cases, rice inorganic Asconcentrations were higher than the limit set by Chinaat 0.2 mg kg^?1. Compost at therate used did not reduce rice grain As to safe levels.Lead–arsenate contaminated soils are not recommended for rice production.     

Characterization of Aerococcus viridans isolated from milk samples from cows with mastitis and manure samples

Thirty-eight Aerococcus viridans isolates were obtained from milk from 478 cows with clinical mastitis in a farm during the periods between November 2011 and February 2012, and between December 2012 and March 2013. Additional isolates were obtained from processed manure (a mixture of composted manure, straw and hydrated lime) and bedding materials. The processed manure was later used to cover the floor of the stalls in barns as bedding materials. The temperatures recorded in the composted and processed manure were not as high as those generally observed during satisfactory composting. To reveal the association of A. viridans in manure-related products with intramammary infection in cows, isolates were characterized by their DNA fragment patterns as determined by pulsed-field gel electrophoresis (PFGE) and antimicrobial susceptibility testing. Isolates obtained from milk, processed manure and bedding materials had identical DNA fragment patterns. Antimicrobial susceptibilities were determined for 29 isolates from milk, processed manure and bedding materials. Of these, 26 (89.7%) were resistant to clindamycin, whereas virtually all the isolates were susceptible to 12 other antimicrobials including cefalosporins that have been used to treat bovine mastitis in Japan. In vitro, three A. viridans isolates from milk and an isolate from processed manure survived for 3 hr in Good’s buffer (pH 9) at high temperature (50°C). The results suggest that the processed manure and bedding materials in this farm were possible sources of A. viridans that caused infection in the cows with mastitis.     

蚯蚓堆肥和蚯蚓发酵液体肥在设施葡萄上应用研究

以设施栽培的‘红地球’葡萄为试验材料，采用单因素完全随机设计，研究了蚯蚓堆肥与蚯蚓发酵液体肥对葡萄叶片光合能力、植株生长情况、土壤状况和果实品质及产量的影响。结果表明：利用蚯蚓堆肥与蚯蚓发酵液体肥，提高叶绿素相对含量与净光合速率11.12%、15.31%，促进葡萄的生长，提高叶片面积、茎粗和新稍生长量7.58%、6.42%、18.86%，开花期促进茎叶磷素的吸收，成熟期促进茎叶钾素的吸收；改善土壤理化性质，降低土壤容重30.43%，显著增加总孔隙度8.63%，增加土壤EC值38.23%，pH值降低8.32%，提高速效氮、磷、钾10.56%、11.11%、12.67%，提升有机质3.15 g?kg-1；活化土壤微生物，提高脲酶、磷酸酶和蔗糖酶66.86%、54.60%、82.03%，细菌、放线菌、真菌数量是对照的3.20倍、0.43倍、3.28倍，提高微生物碳氮14.98%、20.23%，增加可溶性蛋白、Vc、可溶性固形物、糖酸比24.31%、9.74%、5.49%、23.46%，降低可滴定酸13.51%；产量增加了21.73%，并土壤理化性质以及土壤微生物关系密切。