Long-Term Spreading of Olive Mill Wastewater on Olive Orchard: Effects on Olive Production,Oil Quality,and Soil Properties

In Italy, the law no 574 of 1996 permits and regulates the disposal of olive mill wastewater (OMW), the liquid by-product obtained in oil mill when olive fruits are processed to extract virgin olive oil, by its controlled spreading on cultivated soil. With the aim to verify the long-term effects of the practice on olive production, oil quality, and physical–chemical and microbiological characteristics of soil, different amounts of OMW were spread in February, for 9 years consecutively, on soil cultivated with olive trees. The results obtained confirmed that the controlled spreading of OMW is not harmful for the plant production. On the contrary, OMW spread on olive grove is useful for the fertility of soil and the growth of microflora for the important supply of nitrogen (N), phosphorus (P), potassium (K), and, above all, of organic matter. The evaluated biological properties indicated that OMW spreading stimulates the growth of soil fungal and fungus-like communities and aerobic N₂ fix micro-organisms. With regard to the oil quality, the data indicate that no significant differences were ascertained on the analyzed parameters.     

Potential Use of Olive Mill Wastewater as Amendment: Crops Yield and Soil Properties Assessment

The traditional olive oil extraction process generates a large amount of liquid by-product that could be recycled as an organic fertilizer. The aim of this 3-year field experiment was to assess the effects of olive mill wastewater (OMWW) application on yields of ryegrass, proteic pea, and clover crops and on soil properties. The following treatments were compared: OMWW at 80 m³ ha^?1 (80_OMWW), OMWW at 120 m³ ha^?1 (120_OMWW), and an unfertilized control (Contr).

The yields of ryegrass increased 40% and 41.6% compared to Contr, for 80_OMWW and 120_OMWW, respectively, while a significant enhancement was found at the lowest level of OMWW in proteic pea (27.0% increase). Clover showed a species-specific sensitiveness, but the OMWW applications increased the protein content 26.3% and 28.7% for 80_OMWW and 120_OMWW, respectively, in comparison with Contr.

The OMWW rates also enhanced the total organic content in the soil compared to the unfertilized control. At the end of the 3-year experiment, total extracted carbon and humified organic carbon were greater than the initial ones. The values of available phosphorus (P) and potassium (K) determined at the end of experiment in Contr were almost the same as those recorded at the beginning of the research, confirming that the increases found in 80_OMWW and 120_OMWW plots were due to the OMWW applications.

The findings suggest that repeated applications of OMWW could both sustain fodder crop performance and support soil fertility, with the possibility to recycle the organic amendment and reduce the risks of soil degradation.     

施用油橄榄加工废弃物对土壤生化特性的影响

油橄榄加工废弃物(OMW)的任意排放会造成严重的资源浪费和环境污染。合理施用OMW不仅可以改善土壤肥力,而且可减轻对环境的威胁,创造更大的经济效益。OMW施用于土壤中,可显著增加土壤有机物及可溶性有机碳的含量,改善土壤pH值及速效P、K等元素的含量,提高除草剂的利用率;可改变土壤微生物群落结构,增加微生物活动及生物量,促进土壤不稳定有机物的氧化成熟。但是由于OMW中含有较高浓度的酚类化合物,在施用时应严格控制其浓度,以降低对土壤生物的毒性。本文综述了施用OMW对土壤生化特性的影响。     

Effect of Treated Wastewater Irrigation on Plant Growth and Biological Activity in Three Soil Types

The effects of two types of treated wastewater on soil biological activity were studied in a pot experiment. Four irrigation treatments were tested on both soils sown with barley and unsown soils: distilled water (DW), half-strength Hoagland nutrient solution (NS), treated wastewater from a conventional treatment plant (CWW), and treated wastewater from a lagoon (LWW). Three types of soils were used: Chromic Luvisol, Calcaric Regosol, and Calcaric Arenosol. The greatest barley production was obtained under NS treatment in the three soils, whereas the least was produced by the DW treatment. Soil biological activity was strongly correlated to plant production, whereas no effect of treated wastewater irrigation was observed in the unsown soils. The greatest soil biological activity was found in the Luvisol. In conclusion, both soil type and the presence of plant root systems were found to have more influence on soil biological activity than irrigation water type.     

Treated Industrial Wastewater Effects on Chemical Constitution Maize Biomass,Physicochemical Soil Properties,and Economic Balance

Irrigation with treated wastewaters can improve nutrient levels and yield of crops planted on degraded soils. This study evaluated how irrigation with treated industrial wastewater affected biomass production and nutrition of maize plants and physio-chemical properties of a degraded soil. The experiment was conducted in a greenhouse using PVC columns. Treatments consisted of 8 treatments irrigated with clean water and increasing doses of N and P, and 8 treatments with 4 proportions of wastewater irrigation (25%, 50%, 75% and 100% v/v). In general, maize biomass did not differ between irrigation water sources. Differences were largely associated with N nutrition. We observed increases in concentrations of N, P, K, S, Mn, Na, Cu, and Zn in tissue of maize under irrigation with wastewater. The addition of treated wastewater increased the P and Na concentrations, and EC values in the soil without affecting clay dispersion in water. An associated economic analysis indicated that wastewater irrigation would not be economically feasible without including environmental benefits. In southern Brazil, the proportion of irrigation water that is wastewater should not exceed 50%.     

Short-Term Effects of Wastewater Land Application on Soil Chemical Properties

Land application of wastewater has been accepted as an effective wastewater treatment method and disposal option in semiarid and arid areas in the world. Although it has economical, environmental, and social benefits, it is sometimes questioned as an environmentally sound method. Water mass balance method has proved to be an effective approach to designing a wastewater land application system to remove nitrogen at the municipal wastewater treatment plant at the City of Littlefield, Texas, USA. The study in this paper was to evaluate the short-term effects of wastewater land application on soil chemical properties at the same site from 16 June 2006 to 28 June 2007 with the system designed by the water mass balance method. Soil samples were taken at the start and at the end of this study at different depths from soil surface down to 91 cm at the research site (54?×?18 m), and analyzed for pH, total Kjeldahl nitrogen, nitrate–nitrogen, ammonia–nitrogen, electrical conductivity, calcium, magnesium, sodium, and sodium adsorption ratio. The results showed that there was no negative change of those soil chemical properties during the research period in this wastewater land application system designed by water mass balance method.     

免耕年限对东北旱田土壤性质及玉米根系、产量的影响

试验以免耕1年,免耕2年,免耕4年和免耕5年的玉米农田为对象,探索免耕年限对不同层次土壤理化性状及玉米根系和产量的影响。结果表明:随着免耕年限的增加0~40 cm土层土壤有机质、全氮含量、速效氮、速效钾含量显著增加,免耕能够增加土壤养分含量,土壤容重在免耕4年以后比常规耕作显著增加;免耕栽培玉米根系的表面积、根长、体积、根尖数均显著低于传统翻耕,但根系直径差异不显著,且随免耕年限增加,玉米根系在0~20 cm土层呈现集聚现象,说明免耕能够促进玉米根系对0~20 cm土壤养分的吸收;随免耕年限增加,不同免耕年限处理分别比传统翻耕增产7.7%、7.9%、9.7%和4.6%,在免耕4年产量达到最高。综合各项指标测定,免耕应以4年左右为宜。     

造纸废水灌溉对芦苇生长及其土壤改良效应

为研究造纸废水灌溉对中度盐碱退化芦苇湿地的土壤改良效应及对芦苇生长的影响,在大田内设置随机区组试验,研究了4种废水灌溉次数下的芦苇生长指标、土壤理化性状及土壤酶活性的变化特征。结果表明:随着废水灌溉次数的增加,芦苇密度、株高、盖度及地上生物量等生长指标显著增加;土壤容重和总孔隙度分别有减小和增大趋势;土壤pH值有所上升,而含盐量下降趋势显著。土壤有机质、速效N、速效P、速效K、全N及微生物生物量碳均表现出随废水灌溉次数增加有增多趋势,其中有机质、速效N在灌溉2～4次后,分别比CK显著增加32.0%,52.2%,84.6%;8.1%,16.2%,29.4%;而速效P(13.26mg/kg)、全N(0.45g/kg)均在灌溉3次后达到最高;废水灌溉后土壤C/N有减小趋势,有机质腐殖化程度不高。随着废水灌溉次数的增加,磷酸酶、脱氢酶显著增加,灌溉3次后均达到最高;灌溉1～4次后的脲酶含量分别是CK的1.1,1.4,2.0,2.1倍。     

整地时期对土壤物理性质及苹果幼树的影响

为了提高陕北黄土丘陵沟壑区苹果幼树的栽植成活率和保存率,对3个穴状整地时期的土壤物理性状及苹果幼树生长状况进行了监测研究.结果表明,穴状整地后土壤容重降低,土壤总孔隙度和非毛管孔隙度提高.雨季前穴状整地提高了春季和幼树生长前期的土壤水分,减小了土壤日温差,提高了苗木成活率,促进了树体生长.但雨季后和春季穴状整地降低了春季和幼树生长前期的土壤水分,加大了土壤日温差,降低了苗木成活率,削弱了树体生长,并且加深了定植当年的地面塌陷深度,降低了苹果幼树冬春季的枝条含水量,提高了枝条抽条指数,降低了苗木保存率.陕北丘陵沟壑区栽植苹果时应该在雨季前穴状整地.     

地面覆盖对盐渍土水热盐运动及作物生长的影响

利用田间小区试验研究了山东省莱州半干旱海水入侵地区不同覆盖措施对土壤水盐热运动及作物生长的影响,试验结果表明,①塑膜覆盖对盐渍土有很好的保温增温效果和一定的保水抑盐作用;②秸秆覆盖能拦蓄雨水、减少地面径流和地表蒸发,对盐渍土有非常明显的保持土壤水分、抑制地表返盐、促进降雨淋盐的作用,且其作用随覆盖厚度的增加而增强,③秸秆覆盖的隔热性及其对土壤热容量的提高,缓和了土壤温度的日变化;④5cm厚秸秆覆盖的土壤含盐量变化幅度较小,说明秸秆覆盖提高了土壤对盐分的缓冲性;⑤随着油葵的生长,增加了地面的植被覆盖度,削弱了覆盖措施对土壤水盐热运动的影响;⑥5cm秸秆覆盖下的油葵生长状况及其产量均优于其他处理。由此可见,秸秆覆盖是改良利用盐渍土非常有效的一项措施。     

Sewage Sludge Compost's Cumulative Effects on Crop Growth and Soil Properties

? Onion (Allium cepa cv. Spanish Sweet Utah), lettuce (Lactuca sativa cv. Black Seeded Simpson), snapdragon (Antirrhinum majus cv. Sonnet Yellow), and turfgrass (Festuca arundinacea cv. Marathon) were grown twice annually (spring and fall) on a San Emigdio sandy loam (coarse-loamy, mixed calcareous thermic, Typic Xerorthents) soil for two years that was treated with a cumulative total of 0, 37 and 74 MT/ha of sewage sludge compost from San Diego. The soil received two compost treatments each year and crops were planted within a week of compost incorporation. Crop growth was monitored and the results of the fourth or final planting are described here. Seedlings of onion, snapdragon and lettuce transplanted to compost treated plots displayed more vigorous establishment than those in the control plots. Compost treatments produced higher yields of onion, turf and lettuce. Snapdragon yield was not affected by compost treatment. Soil analysis of compost treated plots revealed lowered pH and increased levels of organic matter, primary nutrients, soluble salts and heavy metals.     

复合改良剂对盐碱土改良及植物生长的影响

为探寻更加高效的复合型改良剂，本研究通过田间试验，对土壤理化性质和植物生长指标进行分析，探讨了脱硫石膏、黄腐酸钾和稻壳三种物料不同配比施用对盐碱土理化性质及植物生长状况的影响，筛选出最佳复合物料添加比例，旨在为盐碱地改良与合理利用提供参考依据。结果表明：与对照组相比，不同处理下0-20和20-40 cm土壤pH均有显著降低，分别降低了4.2%~9.6%和4.5%~9.4%。0-20 cm土层的土壤盐分含量也显著降低，土壤中〖HCO〗_3^-、〖Cl〗^-、〖Na〗^+含量分别降低了6.1~39.4%、18%~43.1%和6.2%~33.2%，其中稻壳、黄腐酸钾和脱硫石膏配比为5-1.2-9 t/hm2和15-0.4-9 t/hm2时对〖HCO〗_3^-、〖Cl〗^-、〖Na〗^+降低效果最为明显。复合改良剂均能提高土壤有机质、碱解氮和有效磷含量与景天植株生物量。与对照组相比，有机质增加了3%~46%、碱解氮增加了16.1%~111.8%、有效磷增加了59.5%~154.8%和景天生物量增加了7.1%~47.6%。效应综合评价的主成分分析结果表明，稻壳、黄腐酸钾和脱硫石膏配比为5-1.2-9 t/hm2时是滨海盐碱土壤最适宜的生物化学复合改良剂组分。     

土壤石油污染对植物种子萌发和幼苗生长的影响

为了研究土壤石油污染对植物种子萌发和幼苗生长的影响,选取中原油田地区的原油和潮土,通过盆栽试验研究了不同石油污染水平条件下的植物种子发芽率、株高和鲜重.结果表明,土壤中石油含量不同,对黑麦草(Lolium perenne L.)、高羊茅(Festuca arundinacea)、紫花苜蓿(Medicago sativa L.)、白三叶草(Trifolium repens L.)、红三叶草(Trifolium pratense)的各项生长指标影响不同,当土壤中的石油含量较高时,对植物的生长有抑制作用.向日葵(Helianthus annus L.)、棉花(Gossypium hirsutum L.)、高丹草(Sorghum sudangrass)、狗牙根(Cynodon dactylon)在试验设计石油污染水平范围内发芽率、株高及鲜重受影响较小,能生长在石油污染的土壤上,其中狗牙根,生存能力强,是试验中的最具有修复土壤石油污染研究潜力的植物.     

氟对土壤理化性质和玉米生长的影响

用盆栽试验研究了外源氟对潮土、黄棕壤pH、容重、玉米干物重和吸钾量的影响,结果表明：氟可以提高土壤pH,使土壤结块,容重增加,孔隙度减少,加入氟1000 mg/kg,黄棕壤和潮土pH分别比对照增加了0.77和0.52,土壤容重分别增加了26.98%和27.72%。氟对潮土过氧化氢酶活性没有影响,加入氟600 mg/kg,氟对黄棕壤过氧化氢酶活性产生明显抑制作用;氟对黄棕壤碱性磷酸酶活性无影响,氟400 mg/kg对潮土碱性磷酸酶活性产生明显抑制。加入氟600 mg/kg,土壤中性磷酸酶活性明显降低;氟对黄棕壤酸性磷酸酶活性影响较潮土小。脲酶活性对氟最为敏感,在黄棕壤和潮土中,分别加入氟200 mg/kg和400 mg/kg,土壤脲酶活性明显降低。玉米苗期,氟浓度在400 mg/kg以上,才会对玉米苗期干物质积累产生影响,加入氟1000 mg/kg,黄棕壤和潮土玉米幼苗干物重比对照分别减少了20.1%和9.8%,氟对黄棕壤玉米苗期生长影响比潮土大;随着玉米生长,氟对玉米干物重产生明显影响的浓度越来越低,在玉米拔节期,氟浓度在200～400 mg/kg时,玉米地上和地下部干物重比对照明显减少,氟对玉米根的抑制作用超过玉米地上部。氟对玉米吸钾量影响很大,加入氟浓度高于400 mg/kg时,玉米吸钾量明显减少。加入氟1000 mg/kg,潮土玉米含钾量与对照相比减少了43.7%,黄棕壤玉米减少了41.9%。潮土玉米吸钾量与对照相比减少了59.7%,黄棕壤玉米吸钾量减少了50.9%。     

Plant Nutrition Aspects under Treated Wastewater Reuse Management

A greenhouse pot experiment was conducted in Agrinion, Greece, in 2009, using a Randomized Block Design. Treated Municipal Wastewater (TMWW) in five levels was applied to Brassica oleracea var. Capitata (cabbage) in four replications. The experiment aimed at investigating the effect of TMWW on: (a) the interrelationships of cabbage plant parts (roots, stems, leaves, and heads) heavy metal content, with the respective dry matter yield. (b) The relationship between each individual soil bioavailable diethylenetriaminepentaacetic acid (DTPA extractable) heavy metal, with the dry matter (dm) yield of the abovementioned cabbage plant parts. The heavy metals of cabbage plant parts dry matter were significantly related negatively and statistically with the respective dry matter yield. Similarly, the soil available DTPA-extractable heavy metals were generally negatively affecting the dry matter yield of roots, stems, leaves, and heads. Conversely, Co, Cr, and Cd were found to be positively associated with the dry matter yield increase of the aforementioned plant parts. This effect was indirect, probably being due to contribution in essential elements by the synergistic interactions of these heavy metals with plant nutrients, such as Ca, Mg, Fe, and Mn.     

腐殖酸肥料对杨树生长及土壤性质的影响

利用活化后褐煤腐殖酸为吸附基质制成缓效肥料(NHA),研究了其对盆栽杨树生长、土壤酶及理化性质的影响.结果表明:施肥对杨树生长具有明显的促进作用,腐殖酸(HA)的施用对杨树根系促进作用明显,同常规施BE(UREA)及腐殖酸混合肥料(HAUM)相比,NHA显著增加了杨树的茎重及树高,氮肥利用率显著提高,达到了53.8%;HA的施用提高了土壤中蔗糖酶、碱性磷酸酶、多酚氧化酶的活性,降低了土壤脲酶活性,对过氧化氢酶活性影响不大;同UREA处理相比,HAUM处理及NHA处理不同程度地增加了土壤有机质、速效磷及饱和持水量,而速效钾、可溶性盐分、pH有所降低,同HAUM处理相比,NHA处理土壤中的速效氮和阳离子代换量有所增加.     

生物质炭浸提液对大蒜生长品质及土壤的影响

[目的]证实生物质炭中的水溶性有机碳对作物生长和品质的作用,为生物质炭的应用开辟新的途径。[方法]在实验室制取400,450,500℃小麦秸秆生物质炭,以KOH溶液浸提水溶性有机碳获得生物质炭浸提液W_(400),W_(450),W_(500),并应用于盆栽大蒜试验,研究其对大蒜生长、品质及土壤的影响。[结果](1)W_(400),W_(450),W_(500)对大蒜的生长都没有显著影响;(2)W_(400)处理使大蒜可溶性糖的含量显著提高了27.53%,土壤有机质和速效磷含量分别提高37%,26%;(3)W_(450)处理下大蒜维生素C、大蒜素含量分别显著提高34.9%和8.2%。[结论]生物质炭浸提液对大蒜生长没有影响,但可以提高大蒜品质。     

Interaction Effects of Arbuscular Mycorrhiza Fungi and Soil Applied Herbicides on Plant Growth

Interaction between mycorrhizal fungi and herbicide application and their effects on plant growth are issues around which there is little information. Therefore, to determine the effect of arbuscular mycorrhizal (AM) fungus in alleviating the effects of herbicide stress on growth of maize and barley, two pot experiments were conducted in Shahrood University of Technology in 2009 and 2010. Factorial experiments were arranged in completely randomized design with three replications. Experimental factors were a combination of two factors: (1) non-mycorrhiza (control) and Glommusmosseae, Glommusintraradices and Glommusfasciculatum as mycorrhizal inoculums; (2) herbicide treatments, which included three levels of metribuzin (0, 175 and 350 g a.i. ha^?1). In the second experiment, factors examined were inoculated soil with mycorrhiza fungi at two levels (with and without Glommusintraradices) and four rates of metribuzin (0, 175, 350 and 525 g a.i. ha^?1) and two levels of iron (0 (control) and 20 mg pot^?1). The results showed that soil inoculated with mycorrhiza had significantly increased dry weight, height and chlorophyll content of maize and barley in the low herbicide concentrations (175 g a.i. ha^?1) compared to non-inoculated treatments. Based on our results, mycorrhiza fungi can alleviate crop stress due to low doses of metribuzin injury through increase in plant growth.     

Effects of Wastewater Irrigation on Physicochemical Properties of Soil and Availability of Heavy Metals in Soil and Vegetables

The present study investigated the impact of irrigation with wastewater on nutritional property and heavy‐metal concentrations in the soil and consequent accumulation in vegetables at sites having long‐term uses of wastewater for irrigation. Samples of irrigation water, soil, and root and shoot parts of palak plants were analyzed to determine the concentration of heavy metals. Wastewater irrigation led to increases in the total and phytoavailable heavy‐metal concentrations in the soil at all the sites. Heavy‐metal concentrations in soil under wastewater irrigation were negatively and positively correlated with soil hydrogen potential (pH) and organic carbon (OC), respectively. The enrichment factor and metal pollution index were higher at wastewater‐irrigated sites as compared to the clean water–irrigated ones. The study concludes that wastewater irrigation modified the physicochemical properties of the soil, leading to more availability of heavy metals in the soil and consequently to the plant.     

Effects of Municipal Solid Waste Compost on Soil Properties and Vegetables Growth

ABSTRACT

This work investigates the impact of municipal solid waste compost (MSW-compost) application (0, 50, and 100 t/ha) on the growth, and on nutrient and trace elements content in lettuce and tomato plants grown in large, 40-L pots. Our findings showed inhibition of plants’ growth with increasing dose of MSW-compost, compared to plants receiving conventional fertilization. Growth inhibition was associated with a sharp decrease in soil NO₃–N content. On the other hand, a slower decrease in soil NO₃–N content occurred in non-planted pots amended with MSW-compost. These findings provide evidence that N immobilization and/or decreased N mineralization were responsible for inhibited growth by constraining N availability. With regard to the other macro-nutrients, K, P, Mg, Ca, and Fe, their contents in leaves of both crops were maintained at optimum levels. Higher zinc and copper content was measured in leaves of both crops but they did not exceed the optimum range for growth. No accumulation of trace elements was found in the fruits. The content of heavy metals in the tissues of plants grown in MSW-compost amended soil, remained at levels similar to those of the non-amended soil, suggesting that they do not pose a significant risk either for plant growth or public health. The findings of our study suggest that further emphasis should be given on the investigation of the factors regulating N mineralization and availability in order to avoid reductions in crop yield.