调理剂和通风方式对污泥生物干化效果的影响

采用了自主设计的污泥生物干化实验室模拟系统,研究了调理剂、物料配比和通风方式等实验条件对脱水污泥生物干化的影响效果。研究结果表明,与锯末相比,秸秆有利于反应物料温度的上升,含水率下降程度更大;利用秸秆调节污泥初始含水率在60%和65%的实验条件下时,物料的平均含水率分别下降了7%和6%,当初始含水率65%时,生物堆体的温度和含水率没有明显的变化;与连续通风相比较,间歇通风的实验条件有利于生物堆体的温度的升高和干化效果;在该实验中,最佳的生物干化条件是以秸秆为调理剂,初始含水率调至65%以下,以间歇方式进行通风。     

Microbial Biomass,P-Nutrition,and Enzymatic Activities of Wheat Soil in Response to Phosphorus Enriched Organic and Inorganic Manures

Compost was prepared from wheat straw enriched with Rajasthan rock phosphate and Aspergillus awamori. The resulting phospho-compost along with phosphorus enriched FYM, mineral fertilizer (rock phosphate) and super phosphate were evaluated for their individual contribution in improving organic matter status, P availability, and enzymatic activities of soil under wheat crop grown in a micro plot. The results showed that total organic carbon, nitrogen, microbial biomass, and humus content (an index of organic matter status of soil) of soil was highest when farmyard manure (FYM) after its enrichment with 12.5% rock phosphate was applied. Microbial enriched phospho-compost was the product yielding highest soil available phosphorus, phosphorus uptake, urease, and cellulase activities. However, FYM amended with 25% rock phosphate resulted in the greatest enhancement of β-glucosidase. Measured parameters indicated a sure improvement of chemical and biological activities of soil after the application of phosphorus enriched organic amendments compared to the commercial fertilizer commonly used by the Indian farmers.     

Immobilization of pentachlorophenol in soil using carbonaceous material amendments

In this study, three pentachlorophenol (PCP) laboratory-spiked and one field-contaminated soil were amended with 2.0% char, humic acid (HA) and peat, respectively. The amended soils were aged for either 7 or 250 days. After amendment, CaCl₂ extractability of PCP was significantly decreased. Desorption kinetics indicated that the proposed amendment could lead to a strong binding and slow desorption of PCP in soils. Amendment with char reduced the bioaccumulation factor (BAF) of PCP most significantly for earthworms (Eisenia fetida) in all soils studied. The results of both physicochemical and biological tests suggested that amendment reduced PCP bioavailability quickly and enduringly, implying that carbonaceous material amendment, especially char amendment, was a potentially attractive in situ remediation method for sequestration of PCP in contaminated soil.     

Impact of soil management practices on yield,fruit quality,and antioxidant contents of pepper at four stages of fruit development

Peppers, a significant component of the human diet in many regions of the world, provide vitamins A (β-carotene) and C, and are also a source of many other antioxidants such as capsaicin, dihydrocapsaicin, and phenols. Enhancing the concentration of antioxidants in plants grown in soil amended with recycled waste has not been completely investigated. Changes in pepper antioxidant content in relation to soil amendments and fruit development were investigated. The main objectives of this investigation were to: (i) quantify concentrations of capsaicin, dihydrocapsaicin, β-carotene, ascorbic acid, phenols, and soluble sugars in the fruits of Capsicum annuum L. (cv. Xcatic) grown under four soil management practices: yard waste (YW), sewage sludge (SS), chicken manure (CM), and no-much (NM) bare soil and (ii) monitor antioxidant concentrations in fruits of plants grown under these practices and during fruit ripening from green into red mature fruits. Total marketable pepper yield was increased by 34% and 15% in SS and CM treatments, respectively, compared to NM bare soil; whereas, the number of culls (fruits that fail to meet the requirements of foregoing grades) was lower in YW compared to SS and CM treatments. Regardless of fruit color, pepper fruits from YW amended soil contained the greatest concentrations of capsaicin and dihydrocapsaicin. When different colored pepper fruits (green, yellow, orange, and red) were analyzed, orange and red contained the greatest β-carotene and sugar contents; whereas, green fruits contained the greatest concentrations of total phenols and ascorbic acid.     

Adsorption/Desorption of Copper by a Sandy Soil Amended with Various Rates of Manure,Sewage Sludge,and Incinerated Sewage Sludge

Organic amendments are sometimes applied to agricultural soils to improve the physical, chemical, and microbiological properties of the soils. The organic fractions in these soil amendments also influence metal reaction, particularly the adsorption and desorption of metals, which, in turn, determine the bioavailability of the metals and hence their phytotoxicities. In this study, a Quincy fine sandy (mixed, mesic, Xeric Torripsamments) soil was treated with 0 to 160 g kg^?1 rates of either manure, sewage sludge (SS), or incinerated sewage sludge (ISS) and equilibrated in a greenhouse at near field capacity moisture content for 100 days. Following the incubation period, the soil was dried and adsorption of copper (Cu) was evaluated in a batch equilibration study at either 0, 100, 200, or 400 mg L^?1 Cu concentrations in a 0.01M CaCl₂ solution. The desorption of adsorbed Cu was evaluated by three successive elutions in 0.01M CaCl₂. Copper adsorption increased with an increase in manure rates. At the highest rate of manure addition (160 g kg^?1 soil), Cu adsorption was two-fold greater than that by the unamended soil at all rates of Cu additions. With increasing rates of Cu additions, the adsorption of Cu decreased from 99.4 to 77.6% of Cu applied to the 160 g kg^?1 manure amended soil. The desorption of Cu decreased with an increase in rate of manure amendment. Effects of sewage sludge amendments on Cu adsorption were somewhat similar to those as described for manure additions. Likewise, the desorption of Cu was the least at the high rate of SS addition (160 g kg^?1), although at the lower rates there was not a clear indication of the rate effects. In contrast to the above two amendments, the ISS amendment had the least effect on Cu adsorption. At the highest rate of ISS amendment, the Cu adsorption was roughly 50% of that at the similar rate of either manure or SS amendments, across all Cu rates.     

2-Undecanone and 2-tridecanone in field-grown onion

A field study was conducted to investigate the impact of soil amendments on concentrations of two volatile organic compounds, 2-undecanone and 2-tridecanone, in onion bulbs. The soil in five plots was mixed with sewage sludge, five plots were mixed with yard waste compost, five plots were mixed with laying hen manure each at 15 t acre^?1, and five unamended plots that never received soil amendments were used for comparison purposes. Plots (n = 20) were planted with onion, Allium cepa L. var. Super Star-F1 bulbs. Gas chromatographic/mass spetrometric (GC/MS) analyses of mature onion bulbs crude extracts revealed the presence of two major fragment ions that correspond to 2-undecanone and 2-tridecanone. Soil amended with yard waste compost enhanced 2-undecanone and 2-tridecanone production by 31 and 59%, respectively. Soil amended with chicken manure enhanced 2-undecanone and 2-tridecanone production by 28 and 43%, respectively. Concentrations of 2-undecanone and 2-tridecanone were lowest in onion bulbs of plants grown in sewage sludge and unamended soil, respectively. The increased concentrations of 2-undecanone and 2-tridecanone in onion bulbs may provide a protective character against insect and spider mite attack in field grown onions.     

Chicken manure increased concentration of organic sulfur compounds in field-grown onions

A field study was conducted at Kentucky State University (KSU) Research Farm. The soil in five plots was mixed with sewage sludge, five plots were mixed with yard waste compost, five plots were mixed with laying hen manure each at 15 t acre^?1, and five unamended plots that never received soil amendments were used for comparison purposes. Plots were planted with onion, Allium cepa L. var. Super Star-F1. The objectives of this investigation were to: 1) determine the concentrations of two organosulfur compounds (dipropyl disulfide and dipropyl trisulfide) in onion bulbs and 2) investigate the effect of mixing soil with three amendments (sewage sludge, yard waste, and chicken manure) on the concentration of dipropyl disulfide and dipropyl trisulfide in onion bulbs. Gas chromatographic/mass spectrometric (GC/MS) analyses of onion oil in chloroform extracts revealed the presence of two major fragment ions that correspond to dipropyl disulfide and – trisulfide. Concentration of these two organic sulfur compounds was greatest (1.5 and 0.8 mg 100 g^?1 fresh weight, respectively) in onion bulbs of plants grown in chicken manure and lowest (0.4 and 0.07 mg 100 g^?1 fresh weight, respectively) in onion bulbs of plants grown in yard waste compost treatments. We concluded that chicken manure could be exploited in growing onions with health-promoting properties.     

Use of amendments to reduce leaching loss of phosphorus and other nutrients from a sandy soil in Florida

Goal, Scope and Background Transport of P from agricultural land contributes to the eutrophication of surface waters. Soil amendment is considered one of the best management practices (BMPs) to reduce P loss from sandy soils. Laboratory column leaching experiments were conducted to evaluate the effectiveness of different soil amendments in reducing P leaching from a typical sandy soil in Florida. Methods The tested amendments were CaCl₂, CaCO₃, Al(OH)₃, cellulose, and mill mud, and applied at the rate of 15 g/kg for a single amendment and each 7.5 g/kg if two amendments were combined. Leaching was conducted every four days for 32 days, 250 mL of deionized water being leached for each column per leaching event. Leachates were collected from each leaching event and analyzed for reactive P, PO₄-P, and macro and micro-elements. Results and Discussion Except for the soils amended with CaCl₂, or CaCl₂+CaCO₃, reactive P and PO₄-P leaching losses mainly occurred in the first three leaching events. Phosphorus leaching from the soils amended with CaCl₂ or CaCl₂+CaCO₃ was less but more persistent than that of other amendments. Reactive Pleaching loss was reduced by 36.0% and 40.4% for the amendments of CaCl₂, and CaCl₂+CaCO₃, respectively, as compared with chemical fertilizer alone, and the corresponding values for PO₄-P were 70.8% and 71.9%. The concentrations of K, Mg, Cu, and Fe in leachate were also decreased by CaCl₂ or CaCl₂+CaCO₃ amendment. Among the seven amendments, CaCl₂, CaCO₃, or their combination were most effective in reducing P leaching from the sandy soil, followed by cellulose and Al(OH)₃, the effects of mill mud and mill mud + Al(OH)₃ were marginal. Conclusions These results indicate that the use of CaCl₂, CaCO₃, or their combination can significantly reduce P leaching from sandy soil, and should be considered in the development of BMPs for the sandy soil regions. Recommendations and Outlook Most agricultural soils in south Florida are very sandy with minimal holding capacities for moisture and nutrients. Repeated application of fertilizer is necessary to sustain desired yield of crops on these soils. However, eutrophication of fresh water systems in this area has been increasingly concerned by the public. Losses of P from agricultural fields by means of leaching and surface runoff are suspected as one of the important non-point contamination sources. The benefits and effectiveness of soil amendment in reducing P losses from cropping production systems while sustaining desired crop yield need to be demonstrated. Calcium chloride, CaCO₃, or their combination significantly reduce Pleaching from sandy soil, and should be considered in the development of BMPs for the sandy soil regions.     

Use of Flyash as Environmental and Agronomic Amendments

Coal combustion power plant flyash materials have been reported as useful soil amendments with agronomic and environmental benefits. This paper reports the efficacy of fluidized bed combustion (FBC) and flue gas desulfurization (FGD) byproducts, when amended with dairy, swine, and broiler litter manures, in reducing phosphorus (P) solubility and potential impact on water quality. At a rate of 400 g/kg, FBC reduced water soluble P by 60% for dairy and swine and 50% for broiler litter, as compared to un-treated control samples. Byproduct FGD had little effect when amended into dairy manure, but reduced water soluble P by nearly 80% when amended into swine and broiler manure at a rate of 250 g/kg. The amount of Ca added in the amendments together with pH of the mixture is the major contributing factor in soluble P reduction. Sequential extraction results showed that the flyash treatments shifted water soluble P into mainly bicarbonate extractable P. The latter is still considered available for crop uptake but less vulnerable for environmental losses. Coal combustion byproducts, when amended into manure and used properly, can provide a useful and viable option for improving nutrient management on animal farms.     

稻-麦轮作模式下不同钝化材料对镉污染农田土壤的原位钝化效应

为明确大田条件下施用钝化材料对镉(Cd)污染农田土壤的原位钝化效应及其持续性,以秸秆生物炭、 YH粉、粉煤灰、海泡石和页岩粉(粒径均<0.2 mm,施用量均为2.25kg·m^-2)这5种钝化材料为研究对象,连续监测3 a稻-麦轮作模式下原位钝化处理对土壤养分、土壤酸碱度、土壤Cd污染状况和种植作物籽粒Cd含量的影响,探讨其钝化效应及持续性,为有效控制农田土壤Cd污染、保证作物安全生产提供理论依据和数据支撑.结果表明：(1)稻-麦轮作模式下,施用5种钝化材料对土壤养分含量影响较小,但均可提高土壤pH,促使土壤Cd由酸提取态向残渣态转化,降低土壤Cd有效性,其中秸秆生物炭与YH粉处理下当季土壤有效Cd含量的降幅最大(20.42%～22.53%),是其它钝化处理的1.07～1.84倍.(2)稻-麦轮作模式下,首年施用5种钝化材料后均显著降低了水稻和小麦籽粒Cd含量,降幅分别达19.88%～48.77%和5.06%～24.00%.施用秸秆生物炭、粉煤灰和YH粉后作物籽粒Cd含量显著低于对照和其它钝化材料,该处理条件下的水稻籽粒ω(Cd)(0.195、0.197和0....