不同施用方式下污泥堆肥对土壤性质和草坪生长的影响

为解决城市污泥处理难题,探讨污泥堆肥及其不同施入方式对绿地土壤的改良效果,进行了污泥堆肥绿地土壤改良试验。试验设混合(H)、覆盖(F)、混合+覆盖(HF)3种施入方式,结果表明:不同施入方式均能显著降低绿地土壤容重,提高土壤中有机质、碱解氮、速效钾、有效磷含量,HF和H的改良效果最好;不同施入方式还均能显著促进草坪生长和分蘖,其中HF,F,H处理的分蘖密度分别比对照高45%,37%,32%;F处理的杂草抑制率在96%以上,HF为78%,H处理未能抑制杂草;各施入方式均能显著提高土壤微生物碳和土壤微生物氮含量,改良1年后,F、H和HF的土壤微生物碳含量分别是对照2.4,3.1,3.4倍,微生物氮含量分别是对照的1.7,3.0,2.8倍;与对照相比,HF处理与H处理的土壤脲酶、酸性磷酸酶和蔗糖酶活性均显著提高。     

Water and Atrazine Movement in a Calcareous Compost Applied Soil During Simulated Multiple Storms Events

The retention and movement of water and atrazine (2-chloro-4-ethylamino-6-isopropylamino-s-triazine) was investigated in a calcareous soil (Krome) amended with three types of compost: (1) Clean organic waste (COW)- municipal solid waste cleaned of plastic materials and metal containers, (2) Biosolids (BSD)- sludge from municipal waste and (3) Bedminster (BDM)—a mixture containing 75% COW and 25% BSD. The research was conducted in two phases; a column-leaching study (dynamic) and a batch-equilibrium method (static). The column study demonstrated that while applying simulated rain, atrazine, leached out at a slower rate by 41, 24, and 18% from soil amended with BDM, BSD, and COW composts, respectively, during the first simulated storm event. BDM application resulted in lowest water movement and atrazine-leaching rate compared to the other composts tested. This study suggests that adding 134 t ha^?1 of compost to the calcareous soil increased soil water holding capacity, reduced water movement and increased atrazine detention and reduced leaching potential of atrazine thereby reducing the potential for groundwater pollution. This study further demonstrates that soil amendment (particularly BDM) is effective in reducing the leaching potential of atrazine at the low rainfall amounts (corresponding to 0.5 pore volume). However, such amendment may not be effective in preventing leaching under more intense rain conditions or multiple rainfall events (corresponding to 3 or more pore volumes).     

湿陷性黄土试坑浸水试验中土压力及含水量变化分析

湿陷性是黄土的重要性质之一,湿陷性黄土遇水发生湿陷变形的过程中,黄土土层的土压力及含水量相应的发生一系列变化。通过湿陷性黄土现场试坑浸水试验,利用布设在试坑内及试坑周围埋设的传感器和张力计等监测仪器,对试验过程中黄土土层的土压力及含水量的变化过程做了信息采集记录,分析了其变化方式及规律。研究结果表明,在试验过程中黄土土层的土压力及基质吸力均呈降低趋势;在黄土湿陷变形过程中,沉降或突降的时间点一般是在土层压力最小或接近最小,含水量达到或接近饱和的时段。     

High Rate of Nitrogen Fertilization Increases the Crop Water Stress Index of Corn under Soil Drought

Soil nitrogen (N) availability is dominated by soil water regime and the N fertilizer levels, which affect crop growth in soil water stress. To determine the optimum N applications under different degrees of soil drought, this study investigated the effects of N fertilizer levels on the crop water stress index (CWSI) of summer corn under soil water stress. A 2-year field experiment was conducted in waterproof plots in upland red soils in subtropical China. Three N fertilizer levels and seven soil water deficit levels were employed in 2007 and 2008. Nitrogen fertilization had no influence on the CWSI of the corn under slight to moderate soil drought, but the high-N treatment increased the CWSI significantly (P < 0.01) under soil drought when the mean CWSI exceeded ～0.20. The results suggested that for scheduling irrigation or predicting crop yields, the equations between CWSI and yield should be established on comparable N fertilization levels.     

Compost Source and Rate Effects on Soil Macronutrient Availability Under Saint Augustine Grass and Bermuda Grass Turf

Compost application to turf grasses can increase availability of nutrients in soil and improve growth, but can potentially lead to accumulation of macronutrients in soil and contribute to leaching and runoff losses. The objectives of this study were to investigate the influence of compost source and application rate on concentrations of plant-available macronutrients in soil over 29 months after a one-time application to saint augustine grass [Stenotaphrum secundatum (Walt.) Kuntze] and Bermuda grass [Cynodon dactylon (L.) Pers.] turf. Compost application increased soil organic C, P, Ca, and S concentrations by 3 months after addition, but further increases from 3 to 29 months were seldom observed. In contrast, NO₃-N and K levels declined while Mg levels increased slightly from 3 to 29 months. Seasonal or cyclical patterns of soil macronutrient levels were apparent, as lower concentrations were observed during dormant stages of Bermuda grass growth in winter. Initial macronutrient concentrations of compost sources strongly influenced macronutrient dynamics in surface soil, while higher application rates resulted in higher levels of P, K, Ca, Mg, but not NO₃-N and S. Higher levels of macronutrients in Bermuda grass than saint augustine grass turf suggested plant-mediated uptake and assimilation differed between turf grass species. Utilization of turf grass systems for compost application should take into account plant species composition and the related impacts of plant uptake. Macronutrient concentrations were significantly correlated with both total organic C and dissolved organic C (DOC). Formation of organic matter-cation complexes appeared to influence macronutrient dynamics in soil, and may contribute to leaching and runoff losses.     

Humus-Rich Compost Increases Lettuce Growth, Nutrient Uptake, Mycorrhizal Colonisation, and Soil Fertility

Sandy soils, typical of Australia's west, either have little or no habitat protection for microbes including arbuscular mycorrhizal (AM) fungi, which are essential for nutrient cycling. To minimize this problem, the application of organic matter, such as humus-rich composts, is necessary during vegetable crop production. This study aimed at determining the effects of humus-rich composts on either indigenous or inoculated AM fungal colonisation in roots, lettuce (Lactuca sativa L. var. Quechua) growth, and soil fertility improvement. Four different humus-rich composts with varying humus contents were applied at the same standard rate to lettuce grown under glasshouse conditions for 10 weeks after sowing and compared with two low-humus composts and non-amended soil (control). Humus-rich composts significantly increased lettuce shoot growth, root growth, and AM fungal colonisation in roots. Humus contents in the composts were also correlated with lettuce shoot and root growth. Soil dissolved organic carbon, microbial biomass carbon, and fertility were increased with the application of humus-rich composts. These humus-rich composts, especially the compost of higher humic acid with and without AM inoculation, might have a significant role in sustainable vegetable production, for example lettuce growth. Overall, the results indicate that supplementation with humus-rich compost is highly beneficial to enhance soil fertility and potentially maintain the sustainability of vegetable production.     

Vineyard Compost Supplemented with Trichoderma Harzianum T78 Improve Saline Soil Quality

Understanding soil degradation is especially important in the Mediterranean Region where desertification is a serious problem, and soil salinization is one of the causes. Salinity reduces soil quality, limits crop productivity and brings on long term soil degradation. Therefore the restoration of degraded soils is necessary to reduce land degradation, improve soil fertility and achieve a sustainable food production. The addition of compost supplemented with the beneficial microorganism Trichoderma harzianum isolate T78 to saline soils (NaCl) was studied to determine the impact on soil microbiology, which is the key to restore and rehabilitate degraded soils. The selected Trichoderma harzianum isolate T78 showed high salt tolerance despite the low osmotolerance of the genus Trichoderma . Increasing salt concentration reduced Trichoderma sp colony‐forming units (CFU) from natural soil and adversely affected soil microbial biomass C as well as dehydrogenase, β‐glucosidase, phosphatase and urease activities. Simultaneous amendment of the saline soil with compost and inoculation with T. harzianum T78 improved the soil microbiological quality; the number of T. harzianum T78 CFU did not decrease as NaCl increased. As T. harzianum strain T78 is salt tolerant, increasing the relative abundance of this specific strain would contribute to the rehabilitation of saline soils. Vineyard composts supplemented with T. harzianum T78 represent a promising approach for the treatment and improvement of saline soil properties. Copyright © 2016 John Wiley & Sons, Ltd.     

土壤含盐量与土壤电导率及水分含量关系的试验研究

应用不同盐分含量土壤，进行了土壤电导率与土壤含盐量关系的试验研究，获得了不同含盐量土壤的电导率随水分含量变化的规律，并且建立了土壤含盐量与土壤电导率及水分含量的关系．本文所用方法简便可行，试验结果具有较高精度．本研究为较精确测定土壤含盐量及快　速进行较大规模盐渍土壤调查提供了一种较佳方法．     

典型半自然稀树草原雨季中末期土壤水分分异规律的研究

在大量试验的基础上对雨季中末期典型半自然稀树草原土壤水分进行研究，得出了雨季中末期区域内黏性燥红土土壤水分时空分异特征、黏性燥红土与壤性燥红土的水分含量时空变化特征的对照、壤性燥红土不同植被下土壤水分含量时空变化特征、小流域不同地形部位土壤水分含量空间分异特征等土壤水分分布规律。     

Effect of MSW Compost on Microbiological and Biochemical Soil Quality Indicators

This laboratory incubation study was conducted to evaluate the effect of municipal solid waste compost (MSWC) as a soil amendment on soil quality indicators, such as microbial biomass, and their activities. The MSWC was compared against cow dung manure (CDM), a traditional organic supplement. The comparative study was carried out in water regimes of 60% water holding capacity (WH) of soil and under waterlogged (WL) condition. MSWC was applied to an alluvial soil (Typic Fluvaquent) at the rates of 0, 2.5, 10, 20 and 40 and CDM at 0, 20 and 40 t/ha. Microbial biomass-C (MBC), glucose induced soil respiration (SR), urease and acid phosphatase activities in soil were analyzed following 15, 30, 45, 60, 90 and 120 days of incubation. The parameters studied were significantly higher in CDM-treated than in MSWC-treated soils. Increase in graded doses of MSWC from 2.5 to 40 t/ha substantially increased the MBC, SR, urease and phosphatase activities in the soil. In 60% WH regime, MBC and SR increased for the first 30 days of incubation and then declined. Under the WL regime, the MBC declined while SR increased from 15 days till 120 days of incubation. Urease and phosphatase activities of soil increased for up to 60 days during incubation in 60% WH regime and then decreased. Activities of both the enzymes under WL regime decreased progressively during incubation. There were no negative impacts on the soil quality indicators from high application rates of MSWC.     

Compost Input Effect on Dryland Wheat and Forage Yields and Soil Quality

Organic agricultural systems rely on organic amendments to achieve crop fertility requirements, and weed control must be achieved without synthetic herbicides. Our objective was to determine the crop yield and soil quality as affected by a transition from grass to dryland organic agriculture in the Central Great Plains of North America. This study evaluated three beef feedlot compost(BFC)treatments in 2010–2015 following biennial application rates: 0(control), 22.9, and 108.7 t ha~(-1) on two dryland organic cropping systems: a wheat(Triticum aestivum)-fallow(WF) rotation harvested for grain and a triticale(Triticosecale)/pea(Pisum sativum)-fallow(T/P-F) rotation harvested for forage. The triticale + pea biomass responded positively to the 108.7-t ha~(-1) BFC treatment,but not the 22.9-t ha~(-1) BFC treatment. The wheat biomass was not affected by BFC addition, but biomass N content increased.Beef feedlot compost input did not increase wheat grain yields, but had a positive effect on wheat grain Zn content. Soil total C and N contents increased with the rate of 108.7 t ha~(-1) BFC after three applications, but not with 22.9 t ha~(-1) BFC. Soil enzyme activities associated with N and C cycling responded positively to the 108.7-t ha~(-1) BFC treatment. Saturated salts were high in the soil receiving 108.7 t ha~(-1) of BFC, but did not affect crop yields. These results showed that BFC was effective in enhancing forage yields, wheat grain quality, and soil C and N, as well as specific microbial enzymes important for nutrient cycling. However, the large rates of BFC necessary to elicit these positive responses did not increase grain yields, and resulted in an excessive buildup of soil P.     

Characterization of a USDA Kentucky Bluegrass (Poa pratensis L.) Core Collection for Reproductive Mode and DNA Content by Flow Cytometry

Kentucky bluegrass (Poa pratensis L.) is an important turf and forage grass species with a facultative apomictic breeding behavior. In this study, mature seed and leaf tissue from 38 accessions of a USDA core collection of Kentucky bluegrass were analyzed with flow cytometry to characterize the reproductive mode and DNA content for each accession. Major reproductive pathways for each accession were determined based upon the presence and the position of the peaks observed and the known methods of reproduction for Kentucky bluegrass. While the majority of the accessions exhibited facultative apomictic reproductive behavior with a combination of reduced, zygotic and unreduced, parthenogenic embryo production, obligate sexual or obligate apomictic accessions were also found to be present in this core collection. In addition, reduced, parthenogenic and unreduced zygotic embryos were also detected in several accessions. Flow cytometric analysis of somatic tissue revealed a large range of DNA variation within this core collection. We also examined the sensitivity of flow cytometry in analyzing bulked samples containing a large number of plants with varied DNA content and determined that flow cytometry can effectively detect a plant having a different DNA content within a 15-plant bulk sample. Overall the combination of mature seed and somatic tissue analysis generated important information for the Kentucky bluegrass core collection and can be an effective and affordable tool to characterize even greater numbers of Kentucky bluegrass accessions.     

Municipal Solid Waste Compost Improves Crop Productivity in Saline-Sodic Soil: A Multivariate Analysis of Soil Chemical Properties and Yield Response

A pot experiment was conducted in sandy clay loam saline-sodic soil to assess the effects of farm yard manure (FYM), municipal solid waste (MSW) composts and gypsum application on nitrate leaching, soil chemical properties and crop productivity under rice-wheat cropping system. It also aims at establishing the correlation between soil phsico-chemical properties and yield response using principle component analysis and Pearson correlation analysis. The MSW was decomposed aerobically, an-aerobically and co-composted. Maximum nitrate leaching was observed during rice (75.9 mg L^?1) and wheat (37.2 mg L^?1) with an-aerobically decomposed MSW as compared with control treatment. Results revealed a decrease in soil pH (?6.95% and ?8.77%), electrical conductivity (EC) (?48.13% and ?51.04%), calcium carbonate (CaCO₃) (?40.30% and ?48.96%), and sodium adsorption ratio (SAR) (?40.27% and ?45.98%) with an-aerobically decomposed MSW compost during rice and wheat, respectively. In this treatment, organic matter (OM) (93.55% and 121.51%) and cation exchange capacity (CEC) (19.31% and 31.79%) were the highest as compared with control treatment during rice and wheat, respectively. Rice and wheat growth were significantly (p≤ 0.05) increased by an-aerobically decomposed MSW followed by co-compost, aerobically decomposed MSW, FYM, gypsum and control. Furthermore, Pearson correlation coefficients predicted significant positive correlation of yield with soil OM, and CEC while inverse relationship was observed with EC, pH, CaCO₃, and nitrogen use efficiency. Soil amelioration with organic and gypsum amendments was further confirmed with principal component analysis. This study has proved an-aerobically decomposed MSW as an effective solution for MSW disposal, thereby improving soil chemical properties and crop productivity from sandy clay loam saline-sodic soil.     

Compost Practices for Improving Soil Properties and Turfgrass Establishment and Quality on a Disturbed Urban Soil

Urban land disturbance degrades physical, chemical, and biological soil properties by removing topsoil and compacting the remaining subsoil. Such practices create a soil environment that is unfavorable for vegetation establishment. A 3-year field study was conducted to compare the effects of various one-time compost application treatments on soil properties and re-vegetation of a disturbed soil. A disturbed urban soil received the following treatments: (1) inorganic fertilizer; (2) 2.5-cm-depth surface-applied compost; (3) 2.5-cm-depth incorporated compost; (4) 5.0-cm-depth incorporated compost; (5) inorganic fertilizer plus 0.6-cm compost blanket; and (6) inorganic fertilizer plus straw mat cover. The plots were seeded with a mixture of tall fescue Festuca arundinacea Shreb.: ‘Magellan,’ ‘Coronado Gold,’ ‘Regiment,’ and ‘Tomcat,’ perennial ryegrass Lolium perenne L. ‘Linn’, and Kentucky bluegrass Poa pratenis L. ‘Baron.’ Soil chemical and physical attributes and plant growth and quality parameters were measured during 840 days following study establishment. Soil C, N, P, K, Ca, and Mg, and turfgrass growth and quality were increased and soil bulk density was reduced by amending with composts. Incorporation of compost into soil improved soil and plant attributes more than unincorporated surface application, but the differences diminished with time. Compost benefits increased with time. One-time applications of compost can provide immediate and long-term benefits to soil and plant attributes, but there may be no need to incorporate the compost into soil, particularly if the soil has recently been loosened by tillage.     

开展水土流失监测 提高水土保持科技含量

万州区的水土流失类型和水土保持治理模式在三峡库区、渝东地区具有典型的代表性。万州区缺乏及时、准确、全面的水土流失动态监测数据,给水土保持宏观决策、监督执法、编制水土保持生态环境建设规划和实施计划增加了困难。经万州区机构编制委员会办公室批准于1999年成立了万州区水土保持监测站,展开水土流失监测工作,并通过点面结合布设站点、加强技术人员培训、科学分析监测成果等措施,来提高水土保持科技含量。     

Effect of Aquasorb and Organic Compost Amendments on Soil Water Retention and Evaporation with Different Evaporation Potentials and Soil Textures

Abstract

Aquasorb PR3005A, a hydrophilic polymer (a salt copolymer polyacrylamide), and garden waste compost were added to a loamy sand and a loam soil in pots to assess their impact upon soil physical properties at two different evaporation potentials. Compost was mulched and incorporated, the Aquasorb was incorporated, and their effect on temperature and amelioration of soil water content and evaporation was investigated. Mulching with compost reduced evaporation and increased soil temperature. Maize (Zea mays var. single cross 704) was sown in the same pots later, and growth indicator factors (plant height, fresh and dry weight, root weight, and leaf area) were compared. It was concluded that compost mulch application is beneficial to soil water retention whereas compost incorporation did not show these benefits. Compost mulch advances seedling emergence and enhances early growth through hydrologic soil amelioration. High rates of Aquasorb were also beneficial in advancing the emergence and early growth of maize seeded in loamy sand. The hydration capacity of Aquasorb is reduced as the electrolyte concentration and electrical conductivity are increased. Increased electrolyte concentration in soil solution, through drying, may result in gel dehydration and water release at potentials greater than field capacity, which may be lost to drainage. Furthermore, it is concluded that pot experiments with amendments fail to simulate field conditions.     

Combined Application of Potassium and Zinc Improves Water Relations,Stay Green,Irrigation Water Use Efficiency,and Grain Quality of Maize under Drought Stress

Abstract

Maize (Zea mays L.) plays an important role in the global food security, but its production is threatened by climate change, especially drought stress. Potassium (K) and zinc (Zn) are considered useful to mitigate the negative consequences of drought stress in plants. Therefore, the objective of this two-year study was to identify the best combination of K and Zn application to improve the water relations, photosynthetic pigments, yield, irrigation water use efficiency (IWUE) and grain quality of maize sown under mild and severe drought stress conditions. The consisted of three drought stress levels viz. 1) well-watered as control (WW), 2) mild drought (MD) with 25?mm of potential soil moisture deficit (PSMD), 3) severe drought (SD) with 50?mm of PSMD and six K-Zn treatments: i.e. 125, 100 and 150?kg ha^?1 K with 0 and 12?kg ha^?1 Zn. The results indicated that K-Zn application improved the water relations and chlorophyll contents, biological yield and grain quality, irrespective of water stress treatment. The combined application of K-Zn under mild drought stress produced statistically same biological yield and grain quality as under well-irrigated without K-Zn fertilization and also produced compratively higher IWUE, biological yield and grain quality under sverer drought stress. Hence, the application of K at 150?kg ha^?1 in combination with Zn at 12?kg ha^?1 might be useful to improve the maize production and grain quality under drought stress. As IWUE was low in WW conditions, therefore, irrigation scheduling must be re-evaluated for optimum water use efficiency.     

Modification of Soil Water Retention and Biological Properties by Municipal Solid Waste Compost

A compost originating from the organic fraction of MSW, separately collected, was added to a loamy soil at different application rates. Modifications of soil physical and biological properties were studied after compost addition. Water retention properties, after compost addition to soil, were monitored. Organic carbon mineralization was followed during a six-month incubation. Enzyme activities were assayed immediately after compost addition, as well as after incubation of soil-compost mixtures. These properties provided information about the modification of overall microbiological activity and specific nutrient cycles in the amended soil. Water retention, carbon mineralization and most enzyme activities after incubation were increased by compost incorporation. The additivity or nonadditivity of compost effects on soil properties was discussed.     

Utilization of Compost Increases Organic Carbon And Its Humin,Humic and Fulvic Acid Fractions In Calcareous Soil

Organic carbon sustainability in a gravelly calcareous soil is a great challenge under the humid conditions of south Florida. The beneficial effects of compost utilization on soil fertility prompted an investigation on (i) accumulation of total organic carbon and (ii) the soil organic carbon (SOC) in humin, humic acid (HA) and fulvic acid (FA) fractions in a gravelly calcareous soil amended with composts or inorganic fertilizer. In 1996 and 1998, compost from municipal solid waste (MSW) (100% MSW), Bedminster cocompost (75% MSW and 25% biosolids) and biosolids compost (100% biosolids) at 72, 82.7 and 15.5 Mg ha^?1, respectively, were each incorporated in soil beds and inorganic fertilizer (6-2.6-10) NPK at 2.8 Mg ha^?1. A control (no amendment) treatment was also included. Total organic carbon and various fractions of soil organic carbon were determined in two depths (0-10 and 10-22 cm) for both soil particles (< 2mm) and pebbles (> 2mm). Inorganic and organic soil amendments had decreased soil pH and increased soil electrical conductivity (EC) 19 months from initial application. Total organic carbon contents in soil particle were 4-, 3-, and 2-fold higher in MSW compost, Bedminster cocompost and biosolids compost treatments, respectively, than those in fertilizer treated or non-treated soils. MSW compost increased total organic carbon in pebbles by 4- and 3-fold in the 0-10 and 10-22 cm deep layers, respectively, more than other treatments. The soil organic carbon accumulation decreased with depth in all treatments in soil particles, but did not in pebbles. Amending soils with MSW compost significantly increased the organic carbon in humin, HA and FA fractions more than those treated with inorganic fertilizer or non-amended. MSW compost has a potential to be used as a soil amendment to increase and sustain the organic carbon in calcareous soils of south Florida.     

土壤初始含水率对涌泉根灌土壤水分及氮素运移特性的影响

为了探究涌泉根灌水肥一体化灌溉在不同土壤初始含水率下水氮运移特性,通过室内肥液入渗试验,研究了不同土壤初始含水率(4.13%,7.21%,8.77%,11.06%,14.01%)条件下入渗特性、湿润锋运移、土壤水分以及铵态氮和硝态氮的运移特性,建立了涌泉根灌累积入渗量、各向湿润锋运移距离与不同土壤初始含水率之间的关系,提出了不同初始含水率下涌泉根灌累积入渗量、各向湿润锋运移距离的经验模型。结果表明:累积入渗量、各向湿润锋运移距离以及湿润体内水分和氮素的分布、转化等均不同程度地受到土壤初始含水率的影响。同一时刻条件下,累积入渗量随着土壤初始含水率的增大而减小,而湿润锋运移距离却呈现出增大的趋势;土壤初始含水率越大,湿润体体积越大,湿润体内水分、铵态氮和硝态氮的分布范围越广泛;距离灌水器出水孔越近,土壤中的铵态氮和硝态氮含量越高。入渗系数K随着土壤初始含水率的增大而减小,入渗指数α随着土壤初始含水率的增大而增大;水平湿润锋拟合参数a、b均随土壤初始含水率的增大而增大,竖直向下湿润锋运移指数c随着土壤初始含水率的增大而增大,入渗指数d随着土壤初始含水率的增大而减小。随着土壤水分再分布的持续进行,湿润体内水分分布越加均匀,采用克里斯琴森均匀系数Cu评价灌水结束、再分布1,3天条件下湿润体内水分分布均匀度依次为61.99%,74.27%和83.60%;湿润体内铵态氮含量逐渐减小,但铵态氮的分布区域基本无变化;湿润体内硝态氮分布区域变大,平均值呈增大,最值区域有下移趋势。研究成果为进一步研究涌泉根灌水氮高效利用技术奠定了基础。