Wastewater Treatment Trial by Double Filtration on Granular Activated Carbon (GAC) Prepared from Peanut Shells

The aim of this work is the purification of wastewater by double filtration on granular activated carbon prepared from peanut shells. The samples of carbonized peanut shells were activated with 35% sulfuric acid and finally, we proceeded to the purification tests on double filtration of wastewater. Granular activated carbons (GAC) were very effective for the treatment of turbidity, dissolved oxygen, suspended solids, iron, COD and BOD5 but the best results were observed with nitrite, nitrate and phosphate. However, the second filtration was the most efficient while the lowest rates were observed for pH (17.91% on average), and conductivity (29.71% on average). In addition, this work has allowed increasing the dissolved oxygen by more than 50.16% at the exit of the first filter and more than 105.36% at the exit of the second filter. This study shows that granular activated carbon prepared from peanut shells could be a credible alternative for developing countries in the control of pollution and environmental protection.

Assessment of groundwater quality with special emphasis on nitrate contamination in parts of Gautam Budh Nagar district,Uttar Pradesh, India

Progressive developments in industrial and agricultural activities are causing a critical stress on groundwater quality in developing countries.The objective of this paper is to assess and evaluate the contamination level of groundwater caused by leachate in 11 villages of the Gautam Budh Nagar district in Uttar Pradesh,India.We systematically sampled 22 groundwater samples and 13 leachate samples to ascertain the source of pollution on groundwater quality.The standard analytical methods given by the American Public Health Association(APHA)(Standard methods for examination of water and wastewater,23rd edn.APHA,AWWA,WPCF,Washington,2017)were used for quantitative estimation of hydrochemical parameters of collected samples.The results of the analysis of groundwater samples indicate that pH values range from 7.31 to 8.97.The mean magnesium concentration in groundwater samples is 58.93±21.44 mg/L.Out of the groundwater samples taken,approximately 41%and 73%of samples analysis results have been found beyond the acceptable limit with respect to the parameters of turbidity and total dissolved solids,respectively,according to the Bureau of Indian Standards(Indian standard specification for drinking water(IS:10500).BIS,Manak Bhawan,New Delhi,2012)for drinking water.Around 95.4%of groundwater samples and 92.3%of leachate samples have high nitrate concentrations above the standard limit of BIS(45 mg/L),respectively.The Piper plot shows that 50%of the samples belong to the Ca^2+-Mg^2+-HCO3^-type.Ternary and Durov's diagrams indicate that the mean concentrations of ions are in the order of Na^+>Mg^2+>Ca^2+>K^+(for cations)and HCO3^->NO3^->C1^->SO42^->CO32^->F-(for anions)in groundwater of the study area.The spatial variation of the hydrochemical parameters shows that groundwater is heavily contaminated with respect to nitrate.Analytical results indicate that the groundwater of villages Achheja,Bisrakh road,Dujana,Badalpur and Sadopur is not suitable for drinking.

Influence of Potential Evapotranspiration on the Water Balance of Sugarcane Fields in Maui, Hawaii

The year-long warm temperatures and other climatic characteristics of the Pacific Ocean Islands have made Hawaii an optimum place for growing sugarcane;however, irrigation is essential to satisfy the large water demand of sugarcane. Under the Hawaiian tropical weather, actual evapotranspiration (AET) is the primary mechanism by which water is removed from natural and agricultural systems. The Hawaiian Commercial and Sugar Company (HC&S), the largest sugarcane grower of the Hawaiian Islands, has developed a locally optimized AET equation for the purpose of water management on its 184.3 km2 sugarcane plantation on the Island of Maui. In this paper, in order to assess the influence of AET on the hydrological water balance of the HC&S’ sugarcane cropping system, the performance of the HC&S method was compared with three physically-based methods: Penman-Monteith, Priestley-Taylor, and Hargreaves, as well as, to a set of historical pan evaporation data. A Soil and Water Assessment Tool (SWAT) project was setup to estimate the water balance in two sugarcane fields: a windy lowland field and a rocky highland field on a hill slope. Under Hawaiian weather conditions, wind speed was found to be the most influential climatic parameter over potential evapotranspiration (PET);therefore, the results with both Hargreaves and Priestley-Taylor underpredicted PET by approximately 30%, presumably because these methods do not take wind speed into account. The HC&S method was demonstrated to be the most accurate PET method compared to the other commonly used PET equations, with less than 10% error. Of the annual total water supply of 3400 mm, AET accounted for 75% - 80% of the total water consumption. These findings can be used to improve the irrigation efficiency as well as other management scenarios to optimize water use on the Island of Maui.

Shared Management of Water Resources among Sovereign States in Latin America: The Case of the River Plate Basin

The present article sought to address the issue of shared management of water resources among sovereign states in Latin America, focusing on the hydrographic basin of the River Plate. The methodology of the Transboundary Waters Assessment Programme for river basins proposed by the United Nations was used to evaluate risks within current and future scenarios. The results obtained allow the inference that the River Plate basin is in a moderate-risk category. However, high and very high risk values were observed for the pollution, dams and economic reliance indicators, which in the future horizon could promote conflicts regarding water resource use. In conclusion, states should establish their priorities and clear rules for monitoring, use and surveillance of water. This process should be done in an integrated manner, with due regard for international arrangements, and should be compatible with the policies and management instruments of the countries involved.

Groundwater discharge drives water quality and greenhouse gas emissions in a tidal wetland

Wetlands play an important role in the global carbon cycle as they can be sources or sinks for greenhouse gases.Groundwater discharge into wetlands can affect the water chemistry and act as a source of dissolved greenhouse gases,including CO_(2)and CH_(4).In this study,surface water quality parameters and CO_(2)and CH_(4)concentrations were evaluated in a tidal wetland(Hunter Wetlands National Park,Australia)using time series measurements.Radon(^(222)Rn),a natural ground water tracer,was used to investigate the role of groundwater as a pathway for transporting dissolved CO_(2)and CH_(4)into the wetland.In addition,water-to-air CO_(2)and CH_(4)fluxes from the wetland were also estimated.The results showed a high concentration of radon in wetland surface water,indicating the occurrence of ground water discharge.Radon concentration had a strong negative relationship with water depth with a determination coefficient(R^(2))of 0.7,indicating that tidal pumping was the main driver of groundwater discharge to the wetland.Radon concentration also showed a positive relationship with CO_(2)and CH_(4)concentrations(R^(2)=0.4 and 0.5,respectively),while the time series data revealed that radon,CO_(2),and CH_(4)concentrations peaked concurrently during low tides.This implied that groundwater discharge was a source of CO_(2)and CH_(4)to the wetland.The wetland had an average water-to-air CO_(2)flux of 99.1 mmol/(m^(2)·d),twice higher than the global average CO_(2)flux from wetlands.The average CH_(4)flux from the wetland was estimated to be 0.3 mmol/(m^(2)d),which is at the higher end of the global CH_(4)flux range for wetlands.The results showed that groundwater discharge could be an important,yet unaccounted source of CO_(2)and CH_(4)to tidal wetlands.This work has implications for tidal wetland carbon budgets and emphasizes the role of groundwater as a subsurface pathway for carbon transport.

Chemical Characterization of Tomato Industry Wastewater, Florida, United States

Tomato packers often struggle to find ways to reuse the large volumes of wastewater generated during the tomato cleaning and sanitizing processes due to high transportation costs for off-site disposal and strict surface water discharge regulations in Florida. Information about the composition of tomato packinghouse wastewater and the likely sources of major wastewater constituents might provide insights to develop environmentally sustainable practices for wastewater reuse. The objective of this study was to characterize the chemical composition of wastewater generated in tomato packinghouses. The wastewater samples were collected for 6 to 8 hours from dump tanks of two representative packinghouses at 30 minute intervals after start-up of packing operations during May-June 2009. Results showed that wastewater had high electrical conductivity (1.3 - 2.8 dS·m–1) and chloride (255 - 1125 mg·L–1) due to the use of chlorine as a sanitizer in the packinghouses. Concentrations of total phosphorus (P, 2.8 - 5.7 mg·L–1) and copper (Cu, 1.9 - 2.2 mg·L–1) in wastewater were elevated due to tomato cleaning and sanitizing. To reduce P and Cu concentrations, treatment or blending of wastewater may be needed before discharging wastewater to surface waters. Concentrations of P, potassium, calcium, magnesium, zinc, iron, and manganese were much higher in packinghouse 1 as compared to packinghouse 2 wastewater, probably due to the greater contact time of tomatoes with the dump tank water. Whereas concentrations of Cu were similar in both packinghouses wastewater. Greater concentrations of chemical constituents in the wastewater suggest that residues of pesticides, insecticides, and/or foliar-applied micronutrients on tomatoes may be the likely external sources of most constituents (especially P, Cu, and Zn) in wastewater.

Fate of Nutrients, Trace Metals, Bacteria, and Pesticides in Nursery Recycled Water

Faced with rapid population growth and fresh water scarcity, reuse of reclaimed water is growing worldwide and becoming an integral part of water resource management. Our objective was to determine the fate of nutrients, trace metals, bacteria, and legacy organic compounds (organochlorine pesticides) in the recycled water from five commercial nursery ponds in Florida. The pH of recycled water at all sites was 8.1 - 9.3, except one site (6.5), while the electrical conductivity (EC) was 0.31 - 0.36 dS/m. Concentrations of trace metals in recycled water were low: Fe (0.125 - 0.367 mg/L), Al (0.126 - 0.169 mg/L), B (0.104 - 0.153 mg/L), Zn (0.123 - 0.211 mg/L), and Mn (<0.111 mg/L). Total phosphorus (P) and total nitrogen (N) in the recycled water were 0.35 - 1.00 mg/L and 1.56 - 2.30 mg/L, respectively. Among organochlorine pesticides, endrin aldehyde was the only pesticide detected in all nursery recycled water ponds, with concentrations from 0.04 to 0.10 μg/L at four sites and 1.62 μg/L at one site. Other detected pesticides in recycled water were methoxychlor, endosulfan sulfate, dichlorodiphenyldichloroethylene (DDE) and α-chlorodane, with concentrations < 0.20 μg/L. Total coliforms and Escherichia coli (E. coli) in recycled water were 20 - 50 colony forming units (CFU)/100 mL. We conclude that the concentrations of various inorganic and organic compounds in recycled water are very low and do not appear to be problematic for irrigation purposes in Florida’s nursery recycled water ponds.

Biocontrol Potential of Bacillus amyloliquefaciens Bc2 and Trichoderma harzianum TR against Strawberry Anthracnose under Laboratory and Field Conditions

The increasingly strict regulation of the use of phytosanitary products and the will of the populations to move towards sustainable development allow bio-sourced products and more particularly for biocontrol in the field of pesticides to progress. The study carried out here concerns the evaluation of the potency of Bacillus amyloliquefaciens Bc2 and Trichoderma harzianum to fight against strawberry cultures infected with anthracnose (Fragaria × ananassa Duch.). The studies were carried out in the laboratory and in the field. The results indicate that B. amyloliquefaciens Bc2 and Trichoderma harzianum TR are effective for the biological control of anthracnose, gray mold and powdery mildew on strawberries grown in field conditions. The increase in plant size and the number of fruits produced with these control agents has also been observed.

Quantitative Detection of <i>Helicobacter pylori</i>by Real Time PCR in Drinking Water—Environmental and Public Health Risk Significance

Helicobacter pylori (H. pylori) is bacteria considered to be present in half of the population and it is a public health problem worldwide. Most patients infected with H. pylori show no clinical symptoms;nonetheless, approximately 10% to 20% of these patients will develop peptic ulcers and 1% will develop gastric cancer. The International Agency for Research on Cancer has classified H. pylori as a Group 1 carcinogen, recognized as the only bacteria capable of producing cancer. Samples of drinking water (n = 44) from aqueducts with chlorination treatment in selected areas with high prevalence of gastric cancer were analyzed in Costa Rica. Samples of drinking water from Panamá (n = 44) from aqueducts supplying untreated water for human consumption in the province of Chiriquí were also analyzed. The molecular marker of H. pylori, glmM, was used, and to optimize the Real Time PCR (qPCR) technique, annealing temperature, concentration of primers and probe were standardized;also, by analyzing different standard curves, the best reaction conditions that allowed detecting and quantifying the gene were determined. The LightCycler&reg 480 II (LC480II) equipment from Roche Diagnostics GmbH was used, as well as the Absolute Quantification Analysis by means of the Second Derivative Maximum Method. In the case of the samples from Costa Rica, it was determined that 79.5% were positive for H. pylori;removing outlier high average, quantification of bacteria was determined in 3.6 × 103 copies/100 mL. For Panamá it was determined that 86% of the samples were found positive for the presence of H. pylori;removing outlier high average quantification of bacteria was determined at 3.3 × 102 copies/100 mL. The difference in values between the aqueducts in both countries revealed an environmental distribution of the bacteria of epidemiological interest in each case.

The Amazon Basin in the Context of Shared Management of Transboundary Water Resources

The present study addresses the issue of shared management of transboundary water resources, using the Amazon river basin as a case study. To evaluate risks, two scenarios (current and future) were simulated using the methodology proposed by the Transboundary Waters Assessment Programme River Basins. The results obtained allowed the inference that the Amazon Basin, considering all indicators, is in the “moderate” category of risk within the current scenario. In turn, when only the “governance” indicator is considered, reflected through projected water politics tensions, the risk category for the basin becomes “high”, both in the current and future scenarios (2030 and 2050). In conclusion, it is recommended that states should establish clear priorities and rules for water resource monitoring, use and supervision.

Analysis of Water Resources Vulnerability Assessment Tools

Water resources face many pressures and stresses around the world.Assessing the vulnerability of water resources is,therefore,increasingly an essential practice in water resources management.Several studies of water resources vulnerability have been carried out around the world during the last three decades.Thus,the main objective of this study was to analyze water resources vulnerability assessment tools and identify the methodological trend of water resources vulnerability assessment at the local level in existing literature.To achieve this objective,the Preferred Reporting Items for Systematic Reviews and Meta-Analyses(PRISMA)method has been applied to include or exclude articles.Articles on water vulnerability numbering 374 were preselected in the ScienceDirect and the Google Scholar databases.Only 32 out of the 374 articles met the inclusion criteria defined for the analysis.The results show that China(21.9%),U.S.A.(9.4%)and Canada(6.3%)are the most active countries publishing water resources vulnerability assessments.Some 191 vulnerability indicators from the 32 articles were classified into five categories of factors:physical factors(33.5%),socio-economic factors(28.3%),environmental or eco-environmental factors(25.1%),institutions and governance factors(7.3%)and infrastructure factors(5.8%).This study shows that almost half of the studies(47%)considered all five categories of factors,9.4%considered four categories of factors,6.3%considered three categories of factors,28%used two types of factors and 9.4%considered only one category.Researchers have used several methods to assess water resources vulnerability:overlay and index methods(59.4%),process-based models(12.5%),statistical methods(9.4%),overlay and index methods plus process-based model(9.4%),overlay and index methods plus statistical methods(6.3%)and statistical methods plus process-based models(3.1%).Geographic information system(GIS)is an important tool in assessing the vulnerability of water resources with almost 60%of the studies using it at some stage of the assessment.In recent years,there is an increasing trend toward conceptualizing the vulnerability of water resources in a holistic way.

Impact of Agricultural Inputs on Groundwater Pollution in Off-Season Rice Farming in the Pic of Sindou Perimeter in Burkina Faso

Burkina Faso, an 80% agricultural country, today copes the massive use of agricultural inputs to boost productivity. However, these pesticides are sources of pollution of water resources. This is how, the objective of this work was to take stock of the inputs used on the Pic of Sindou rice perimeter and to characterize the vulnerability of the aquifer to these products. The study took place from February to September 2019, where two hundred farmers of the perimeter were investigated on the type and quantity of fertilizers and pesticides used in off-season rice farming activities. The DRASTIC method was used to map the vulnerability of the groundwater resource to these pollutants. Producers use NPK and Urea at 90% and 10% to the organic manure as fertilizers, and herbicides and insecticides with the actives ingredient are Glyphosate, Dimethoate and 2.4 D amine salt. The vulnerability to agricultural pollution of the aquifer remains low, but the risk of contamination from pesticides remains possible.

A Systematic Review and Meta-Analysis of Water Quality Indices

Water quality indices (WQI) are useful tools for indicating the suitability of water for an expected use. However, they can suffer from some problems. The objective of this paper was to analyze the development of WQI to determine which parameters are used in water quality assessment and to discuss the characteristics of WQI. To screen articles on WQI, the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) method is applied to include or exclude articles. Four necessary steps are needed to design WQI: parameter selection, standardization, weighting and aggregation. A set of six methods of aggregations of sub-indices are identified: the arithmetic mean, the geometric mean, the root square, the logarithmic function, the fuzzy inference and the minimum operator. The problems encountered for the overall index are different according to the form of aggregation. They are eclipsing, ambiguity, rigidity or flexibility, adaptability and compensation. The chemical parameters (70%) are the most used in the development of WQI with the physical parameters used at 24% and the biological parameters at 6%. Dissolved oxygen (DO, 87%), total coliforms (87%), biological oxygen demand (BOD, 73%), pH (73%), temperature (67%), turbidity (60%), ammonia (53%), ammonium (47%) and total dissolved solids (47%) are the most commonly used parameters for water quality assessment.

Soil Organic C:N vs. Water-Extractable Organic C:N

Traditionally, soil-testing laboratories have used a variety of methods to determine soil organic matter, yet they lack a practical method to predict potential N mineralization/immobilization from soil organic matter. Soils with high micro-bial activity may experience N immobilization (or reduced net N mineralization), and this issue remains unresolved in how to predict these conditions of net mineralization or net immobilization. Prediction may become possible with the use of a more sensitive method to determine soil C:N ratios stemming from the water-extractable C and N pools that can be readily adapted by both commercial and university soil testing labs. Soil microbial activity is highly related to soil organic C and N, as well as to water-extractable organic C (WEOC) and water-extractable organic N (WEON). The relationship between soil respiration and WEOC and WEON is stronger than between respiration and soil organic C (SOC) and total organic N (TON). We explored the relationship between soil organic C:N and water-extractable organic C:N, as well as their relationship to soil microbial activity as measured by the flush of CO2 following rewetting of dried soil. In 50 different soils, the relationship between soil microbial activity and water-extractable organic C:N was much stronger than for soil organic C: N. We concluded that the water-extractable organic C:N was a more sensitive measurement of the soil substrate which drives soil microbial activity. We also suggest that a water-extractable organic C:N level > 20 be used as a practical threshold to separate those soils that may have immobilized N with high microbial activity.

Growth, yield and fiber quality characteristics of Bt and non-Bt cotton cultivars in response to boron nutrition

Background Boron(B)deficiency is an important factor for poor seed cotton yield and fiber quality.However,it is often missing in the plant nutrition program,particularly in developing countries.The current study investigated B’s effect on growth,yield,and fiber quality of Bt(CIM-663)and non-Bt(Cyto-124)cotton cultivars.The experimental plan consisted of twelve treatments:Control(CK);B at 1 mg·kg^(−1) soil application(SB1);2 mg·kg^(−1) B(SB2);3 mg·kg^(−1) B(SB3);0.2%B foliar spray(FB1);0.4%B foliar spray(FB2);1 mg·kg^(−1) B+0.2%B foliar spray(SB1+FB1);1 mg·kg^(−1) B+0.4%B foliar spray(SB1+FB2);2 mg·kg^(−1) B+0.2%B foliar spray(SB2+FB1);2 mg·kg^(−1) B+0.4%B foliar spray(SB2+FB2);3 mg·kg^(−1) B+0.2%B foliar spray(SB3+FB1);3 mg·kg^(−1) B+0.4%B foliar spray(SB3+FB2).Each treat-ment has three replications,one pot having two plants per replication.Results B nutrition at all levels and methods of application significantly(P≤0.05)affected the growth,physiological,yield,and fiber quality characteristics of both cotton cultivars.However,SB2 either alone or in combination with foliar spray showed superiority over others,particularly in the non-Bt cultivar which responded better to B nutrition.Maxi-mum improvement in monopodial branches(345%),sympodial branches(143%),chlorophyll-a(177%),chlorophyll-b(194%),photosynthesis(169%),and ginning out turn(579%)in the non-Bt cultivar was found with SB2 compared with CK.In Bt cultivar,although no consistent trend was found but integrated use of SB3 with foliar spray performed relatively better for improving cotton growth compared with other treatments.Fiber quality characteristics in both cultivars were improved markedly but variably with different B treatments.Conclusion B nutrition with SB2 either alone or in combination with foliar spray was found optimum for improving cotton’s growth and yield characteristics.

Application of Zinc, Iron and Boron Enhances Productivity and Grain Biofortification of Mungbean

Deficiencies of essential vitamins,iron(Fe),and zinc(Zn)affect over one-half of the world’s population.A significant progress has been made to control micronutrient deficiencies through supplementation,but new approaches are needed,especially to reach the rural poor.Agronomic biofortification of pulses with Zn,Fe,and boron(B)offers a pragmatic solution to combat hidden hunger instead of food fortification and supplementation.Moreover,it also has positive effects on crop production as well.Therefore,we conducted three separate field experiments for two consecutive years to evaluate the impact of soil and foliar application of the aforementioned nutrients on the yield and seed biofortification of mungbean.Soil application of Zn at 0,4.125,8.25,Fe at 0,2.5,5.0 and B at 0,0.55,1.1 kg ha−1 was done in the first,second and third experiment,respectively.Foliar application in these experiments was done at 0.3%Zn,0.2%Fe and 0.1%B respectively one week after flowering initiation.Data revealed that soil-applied Zn,Fe and B at 8.25,5.0 and 1.1 kg ha−1,respectively,enhanced the grain yield of mungbean;however,this increase in yield was statistically similar to that recorded with Zn,Fe and B at 4.125,2.5 and 0.55 kg ha−1,respectively.Foliar application of these nutrients at flower initiation significantly enhanced the Zn contents by 28%and 31%,Fe contents by 80%and 78%,while B contents by 98%and 116%over control during 2019 and 2020,respectively.It was concluded from the results that soil application of Zn,Fe,and B enhanced the yield performance of mungbean;while significant improvements in seed Zn,Fe,and B contents were recorded with foliar application of these nutrients.

Response of Contrasting Rice Genotypes to Zinc Sources under Saline Condition

Abiotic stresses are among the major limiting factors for plant growth and crop productivity.Among these,salinity is one of the major risk factors for plant growth and development in arid to semi-arid regions.Cultivation of salt tolerant crop genotypes is one of the imperative approaches to meet the food demand for increasing population.The current experiment was carried out to access the performance of different rice genotypes under salinity stress and Zinc(Zn)sources.Four rice genotypes were grown in a pot experiment and were exposed to salinity stress(7 dS m^(−1)),and Zn(15 mg kg^(-1)soil)was applied from two sources,ZnSO4 and Zn-EDTA.A control of both salinity and Zn was kept for comparison.Results showed that based on the biomass accumulation and K^(+)/Na^(+)ratio,KSK-133 and BAS-198 emerged as salt tolerant and salt sensitive,respectively.Similarly,based on the Zn concentration,BAS-2000 was reported as Zn-in-efficient while IR-6 was a Zn-efficient genotype.Our results also revealed that plant growth,relative water content(RWC),physiological attributes including chlorophyll contents,ionic concentrations in straw and grains of all rice genotypes were decreased under salinity stress.However,salt tolerant and Zn-in-efficient rice genotypes showed significantly higher shoot K^(+)and Zn concentrations under saline conditions.Zinc application significantly alleviates the harmful effects of salinity by improving morpho-physiological attributes and enhancing antioxidant enzyme activities,and the uptake of K and Zn.The beneficial effect of Zn was more pronounced in salt-tolerant and Zn in-efficient rice genotypes as compared with salt-sensitive and Zn-efficient genotypes.In sum,our results confirmed that Zn application increased overall plant’s performance under saline conditions,particularly in Zn in-efficient and tolerant genotypes as compared with salt-sensitive and Zn efficient rice genotypes.

Cd^(2+)、Cu^(2+)和Zn^(2+)对人工湿地反硝化作用的影响

实验室研究了 3种重金属离子 Cd2 +、Cu2 +、Zn2 +对人工湿地反硝化作用的影响 .以 1 0 0、50 0、1 0 0 0 mg/kg剂量的 Cd2 +、Cu2 +、Zn2 +处理人工湿地土壤样品 ,检测其 N2 O的产生 .结果表明 ,3种金属离子的 50 0、1 0 0 0 mg/kg处理组土样 N2 O的产生均显著降低 ,各金属离子抑制 N2 O产生的程度顺序为 Cd2 +>Zn2 +>Cu2 +,这与 3种金属离子在土样中的有效态浓度顺序是一致的 ,反硝化微生物在处理过程中逐步产生了对重金属离子的耐受性 ,50 0、1 0 0 0 mg/kg处理组样品的 NH+4- N浓度较对照组显著升高提示部分 NO- 3 - N由于反硝化过程的抑制而异化性还原为 NH+4- N.

施用不同土壤改良剂对砖红壤酸度的影响

对砖红壤施用不同的改良剂,经一年的大田试验,测定土壤的活性酸与交换酸研究不同土壤改良剂对酸性土壤酸度的影响。试验结果表明:滤泥单施与石灰单施处理能有效降低土壤的活性酸以及交换性酸的含量,有较好的降低土壤酸度的效果,而施用绿肥、甘蔗渣、羊粪以及羊粪与膨润土混施均不能有效降低土壤的酸度。

施用不同土壤改良剂对砖红壤交换性能影响的初步研究

对砖红壤施用不同的改良剂,进行1a的大田试验后,测定土壤的阳离子交换量、有效阳离子交换量、盐基离子总量以及盐基饱和度来研究不同土壤改良剂对酸性土壤交换性能的影响。结果表明:施用滤泥(40t/hm2)、石灰(2.5t/hm2)以及在施用一定量的羊粪(20t/hm2)基础上施用中量(40t/hm2)或者高量(60t/hm2)膨润土的复合改良剂是有效提升酸性土壤交换性能、增加土壤盐基总量与盐基饱和度的优良措施。