Response of Reservoir Water Quality to Nutrient Inputs from Streams and In-Lake Fishfarms

This study demonstrates how land-use characteristics influence stream water chemistry in a Korean watershed and how stream conditions and in-lake point sources determine trophic state, algal biomass and phytoplankton composition. Measurements of nutrient loads showed that 68% of total phosphorus (TP) loads was originated from the watershed and the remaining 32% came directly from in-lake fish farms. Based on mass balance models, annual areal phosphorus (L _p) and water loading (q _s) were 1.032 g m^-2 and 25 m³ m^-2 yr^-1, respectively, and the total annual P-input exceeded dangerous loading levels according to Vollenweider's classification (1976). In situ Nutrient Stimulation Bioassays (NSB), Trophic State Index (TSI), and mass N:P ratios showed that phosphorus was the primary element regulating algal chlorophyll in the system, and non-algal turbidity and zooplankton effects on algal growth were minor. A high regressioncoefficient in the empirical relationship between chlorophyll (Chl) and TP supported the evidence of strong P-limitation, and model comparisons suggested that our observed Chl values were largely underestimated in models developed for world-wide lakes. Direct P-input to the trophogenic zone from the in-lake fishfarms and streams with intense human-use resulted in massive bluegreen algal blooms, indicating that the highly available input fraction may explain the deviation. Under the circumstances, reduction in P-loading is an essential measure for long-term eutrophication control in this system.     

Control of Algal Scum Using Top-Down Biomanipulation Approaches and Ecosystem Health Assessments for Efficient Reservoir Management

The objectives of this study were algal control and health assessments in a temperate eutrophic reservoir. Laboratory and mesocosm-scale in situ top-down biomanipulation experiments using planktivorous fishes and filter-feeding macroinvertebrates were conducted along with identification of the limiting nutrient using nutrient enrichment bioassays (NEBs), and ecosystem health evaluation based on the modified index of biological integrity model (Reservoir Ecosystem Health Assessment; REHA). Nutrients and N/P ratio analyses during 5 years revealed that the reservoir was in a eutrophic–hypertrophic state and that the key limiting nutrients, based on the NEBs, varied among seasons. Reservoir trophic guilds indicated declines in sensitive and endemic fish species and dominance of tolerant omnivores. Model values from multimetric REHAs averaged 25.8, indicating that the ecological health was in “fair to poor” condition. Overall microcosm biomanipulation tests suggested that macroinvertebrates, specifically Palaemon paucidens and Caridina denticulata, were effective candidates for phytoplankton control, compared to fishes. In situ mesocosm experiments revealed the highest removal rates with bluegreen algae and a phytoplankton size fraction of 2–19 μm (R _e?>?90%, Mann–Whitney U?=?64.5–74.0, p?<?0.01), the dominant fractions in the reservoir. Our biomanipulation technique may provide a key tool for efficient management and restoration of eutrophied reservoirs.     

碱蓬浮床对海水养殖尾水的修复效果

[目的]利用碱蓬浮床对富营养化、高盐碱的海水养殖尾水进行修复,为治理严重的海洋环境问题提供新的方法。[方法]通过设计一种兼具物理、化学、生物协同作用的新型组合式碱蓬(Suaeda salsa)浮床,研究其对富营养化海水养殖尾水中总氮(TN)、总磷(TP)、高锰酸钾指数(COD_(Mn))、氨氮(NH_4~+-N)的去除效果,并与传统浮床进行对比。[结果]组合式浮床对TN,NH_4~+-N,TP,COD_(Mn)的去除率分别为62.14%,93.94%,73.05%和60.91%,较传统浮床去除率分别提高了27.36%,21.27%,19.51%,12.43%。[结论]组合式浮床对富营养化、高盐碱的海水养殖尾水具有明显的修复能力。     

密云水库上游流域水体营养物质现状及来源分析

密云水库作为北京地区最重要的地表饮用水水源地,其水质优劣直接关系到首都的社会经济发展,开展密云水库水污染监测和治理研究具有重要的现实意义。以密云水库上游流域为研究区,通过不同尺度流域水体营养物质监测,分析了水库上游河流水体营养物质现状;通过分割流量过程线,划分了水体营养物质来自点源和非点源污染的比例。研究结果表明,依据标准(GB3838-2002)要求,密云水库上游河流水体TN含量几乎全部超标,且15.9%样本的TP含量超标。密云水库的营养物质平均40.3%来自点源污染,59.7%来自非点源污染;入库水体中50.1%的TN,49.1%的NO₃^--N,39.0%的NH₄⁺-N,26.5%的TP和36.8%的COD_Mn来自点源污染;49.9%的TN,50.9%的NO₃^--N,61.0%的NH₄⁺-N,73.5%的TP和63.2%的COD_Mn来自非点源污染。     

Stable Isotopes in Sedimentary Organic Matter from Lake Dianchi and their Indication of Eutrophication History

Sediment cores were collected from the central and northern parts of Lake Dianchi, a large and shallow eutrophic lake situated in southwest China. Total organic carbon, total nitrogen (TN), and total phosphorus (TP) as well as the δ¹³C and δ¹⁵N were analyzed in the sediment cores. Age model of the sediment cores were established according to ¹³⁷Cs geochronology, which reveals that the sedimentary record covers a period of the last 50 years. During that time, Dianchi had been undergoing a distinct conversion from oligotrophic to eutrophic, as a result of increasing nutrient loadings. The two cores displayed similar increases for values of TN and δ¹⁵N, and the variations of the both parameters matched well with that of TP, which presumably suggested that δ¹⁵N is a reliable proxy for anthropogenic nutrient input. Also, dynamics of δ¹⁵N and TP showed that anthropogenic nutrients input seemed to start in the 1970s. The upward elevation of δ¹⁵N might be ascribed to the increasing input of isotopically heavier dissolved inorganic nitrogen and the accelerated denitrification process when the lake water was oxygen-depleted. The less variation of δ¹⁵N in the uppermost several centimeters of both cores were probably the result of pollution controls carried out by the local government in the recent decade. The upward increasing of δ¹³C in the two cores seemed to be induced by the enhanced productivity since 1980, which was in accordance with limnological observation. Therefore, δ¹³C values were believed to be an effective proxy for reconstructing the history of eutrophication in Lake Dianchi. In addition, this study also suggested that carbon and nitrogen isotopes are applicable to large, shallow lakes in interpreting the past environmental change.     

An Application of Landsat-5TM Image Data for Water Quality Mapping in Lake Beysehir, Turkey

The main goal of this study was to investigate spatial patterns in water quality in Lake Beysehir, which is the largest freshwater reservoir in Turkey, by using Landsat-5TM (Thematic Mapper) data and ground surveys. Suspended sediment (SS), turbidity, Secchi disk depth (SDD), and chlorophyll-a (chl-a) data were collected from 40 sampling stations in August, 2006. Spatial patterns in these parameters were estimated using bivariate and multiple regression (MR) techniques based on Landsat-5TM multispectral data and water quality sampling data. Single TM bands, band ratios, and combinations of TM bands were estimated and correlated with the measured water quality parameters. The best regression models showed that the measured and estimated values of water quality parameters were in good agreement (0.60 < R ² < 0.71). TM3 provided a significant relationship (R ²?=?0.67, p?<?0.0001) with SS concentration. MR between chl-a and various combinations of TM bands showed that TM1, TM2, and TM4 are strongly correlated with measured chl-a concentrations (R ²?=?0.60, p?<?0.0001). MR of turbidity showed that TM1, TM2, and TM3 explain 60% (p?<?0.0001) of the variance in turbidity. MR of SDD showed a strong relationship with measured SDD, with R ²?=?0.71 (p?<?0.0001) for the ratio TM1/TM3 and TM1 band combinations. The spatial distribution maps present apparent spatial variations of selected parameters for the study area covering the largest freshwater lake and drinking water reservoir in Turkey. Interpretation of thematic water quality maps indicated similar spatial distributions for SS, turbidity, and SDD. A large area in the middle portion of the lake showed very low chl-a concentrations as it is far from point and nonpoint sources of incoming nutrients. The trophic state index values were calculated from chl-a and SDD measurements. Lake Beysehir was classified as a mesotrophic or eutrophic lake according to chl-a or SDD parameters, respectively.     

Nutrient Removal in Pilot-Scale Constructed Wetlands Treating Eutrophic River Water: Assessment of Plants, Intermittent Artificial Aeration and Polyhedron Hollow Polypropylene Balls

Seven experimental pilot-scale subsurface vertical-flow constructed wetlands were designed to assess the effect of plants [Typha latifolia L. (cattail)], intermittent artificial aeration and the use of polyhedron hollow polypropylene balls (PHPB) as part of the wetland substrate on nutrient removal from eutrophic Jinhe River water in Tianjin, China. During the entire running period, observations indicated that plants played a negligible role in chemical oxygen demand (COD) removal but significantly enhanced ammonia–nitrogen (NH₄–N), nitrate–nitrogen (NO₃–N) total nitrogen (TN), soluble reactive phosphorus (SRP) and total phosphorus (TP) removal. The introduction of intermittent artificial aeration and the presence of PHPB could both improve COD, NH₄–N, TN, SRP and TP removal. Furthermore, aerated wetlands containing PHPB performed best; the following improvements were noted: 10.38 g COD/m² day, 1.34 g NH₄–N/m² day, 1.04 g TN/m² day, 0.07 g SRP/m² day and 0.07 g TP/m² day removal, if compared to non-aerated wetlands without PHPB being presented.     

Study on the Effect of Periphyton on the Water Quality of Eutrophic Lakes

In this study, we constructed aquatic microcosms, including four experimental groups, to simulate eutrophic lakes. Using polyurethane sponges as artificial substrates to support periphyton, we conducted a systematic study of the effect of periphyton on the water quality of eutrophic lakes by monitoring water-quality indexes including TN, TP, and NTU. The results show that periphyton can effectively degrade N and P in these bodies of water, reduce NTU and the concentration of Chl-a, and restore the aquatic environment. Periphyton can also promote the formation of the DO-Chl-a-NTU-TN-TP synergistic system, which can provide a basis for the comprehensive management of eutrophic lakes. Periphyton can also effectively improve the water quality of eutrophic lakes, and its positive impact on lake ecosystems cannot be ignored during the treatment of eutrophic lakes.     

Algae in the Assessment of Industrial Wastewater Holding Ponds

The ecology and photosynthetic behaviour of the microalgalcommunity in an oil refinery wastewater holding pond was studiedwith a view to assess the role of algae in industrial effluenttreatment ponds. The biological and physico-chemical parameterswere measured for one year from February 1994 to February 1995.The assessment of algal population based on chlorophyll andprimary productivity revealed that the pond is a eutrophic systemsupporting continuous algal bloom. There was no significantcorrelation between the algal biomass and the nutrient parameterstested. A comparison of the algal gross primary production andthe community respiration for the period was done to assess thedegree of waste stabilisation, and it was found that the pondwater is of eutrophic potential. Bioassays of the effluent usingpure cultures of algae, Chlorella pyrenoidosa, Oocystispusilla and Oscillatoria quadripunctulata again confirmedthat the effluent is stimulatory to algal growth. Thus thestudy of algal community in the field surveys and the algalbioassays of the effluent, established that algae can be used asan effective tool to assess the degree of stabilisation of industrial effluents.     

狗牙根与空心莲对水库消落带土壤氮磷释放影响的模拟

通过水库水位涨落室内模拟试验,探究丹江口库区消落带优势物种狗牙根和空心莲2种草本植物对土壤氮磷释放过程影响。结果表明:(1)水淹结束后(32天),空心莲子草土壤TN、TP分别降低11.75%,25.28%,狗牙根分别降低3.62%,25.77%。(2)干湿交替环境主要影响土壤中NH_4~+-N、NO_3~--N和AP的含量的变化,对土壤中的TN、TP含量的影响较小。(3)狗牙根的死亡增加土壤TN、NH_4~+-N、TP量,即不耐淹植被过滤带虽然能净化径流中N、P等污染物,但截留的污染物和植物吸收的养分随着植物体的分解再次进入水体或土壤,无法达到有效防控农业面源污染的目的。该研究为丹江口水库利用植被缓冲带防控水体富营养化提供一定理论依据。     

两种水生植物对重富营养化水体修复效果研究

为了探索重富营养化水体的植物修复方法,在人工模拟条件下选取了两种水生植物伊乐藻(Elodea nuttallii)和黄花水龙(Jussiaea stipulacea Ohwi),采用漂浮生长方式对富营养化水体中养分的去除效果进行研究。结果表明:沉水植物伊乐藻在水面漂浮条件下可起到净化水体的作用,对总氮、氨态氮、硝态氮、总磷、COD、叶绿素a的去除率分别为62.9%,90.83%,53.90%,71.21%,43.33%,50.05%;漂浮植物黄花水龙对上述污染物的去除效果分别为93.56%,97.38%,99.44%,97.74%,52.49%,58.34%。变异分析表明,两者对这些养分的去除达到了显著水平(P<0.05)。黄花水龙对上述污染物的去除效果明显好于漂浮培养条件下的伊乐藻,适合重富营养化水体中养分的去除,而伊乐藻则在水质维持方面发挥更大作用。     

Organic matter production in rice field flood water

To assess the contribution of organic matter produced in the flood water to the fertility of a rice soil, the primary productivity and the algal biomass therein were examined throughout one crop. Primary productivity was estimated from the diurnal curve of dissolved oxygen.

Just after transplanting, an algal bloom developed due to fert,ilizer or ploughing or both. After submerged weeds occupied the whole paddy no distinct algal growth was found. At the ripening stage, the rice plant canopy suppressed the growth of aquatic plants. Benthic algal biomass did not change much throughout the crop period. The standing crop of algae ranged from 2 to 114 kg/ha by fresh weight, while the maximum standing crop of submerged weeds (Najas sp., Chara sp.) was 400 kg/ha by dry weight.

The primary productivity of the flood water community was high (0.6-3.3 g 0 1 m^-2day^-l) and equivalent to productivity values in eutrophic lakes. The total gross primary production of the flood water community during the cropping period corresponded to 10% and 15% of that of rice plant in the fertilized plot and non-fertilized plot, respectively.

Considering the movement of CO₂ in the flood water, it is suggested that the photosynthesis activity in the flood water prevents surplus CO₂ from being lost.     

Effect of Storage Temperature for Paddy on Consumer Perception of Cooked Rice

Effect of storage temperature (ST) (5, 15, and 25°C) for paddy on the consumer perception of cooked rice (CR) was investigated with six major rice cultivars in Korea (Ilmibyeo, Chucheongbyeo, Ilpumbyeo, Hwayeongbyeo, Nampyeongbyeo, and Odaebyeo) after 12 months of storage. Germination rate (GR) of the paddy, grading characteristics (percentages of head rice, broken kernels, damaged kernels, colored kernels and chalky kernels) of milled rice (MR) kernels, texture profile analysis (hardness, springiness, cohesiveness, adhesiveness, and chewiness) and color (L*, a*, and b*) of CR were measured. Also, consumer testing on CR was done with 108 consumers. Consumers evaluated acceptability for odor, appearance, taste, texture, and overall purchase intent, and willingness to pay (WTP) of CR. After 12 months of storage, physicochemical characteristics of MR and CR were significantly different depending on ST. The significant difference among three ST of paddy was noted for GR, color b* value, fat acidity of MR, and overall consumer acceptability of CR. The GR was constant during 12 months of storage at 5°C, whereas a significant decrease of GR was noted for all six cultivars within 12 months of storage at 25°C. The average WTP for rice stored at 5°C for 12 months was $U.S. 45.68/20 kg, whereas WTP for rice stored at 15°C and 25°C were $U.S. 44.19/20 kg and $U.S. 41.87/20 kg, respectively, implying the importance of ST on grain quality and product value by consumers. Overall consumer acceptability had high correlation coefficient with WTP (r = 0.985). Overall consumer acceptability had highest correlation with GR of paddy (r = 0.861), followed by b* value of CR (r = –0.826), fat acidity (r = –0.768), cohesiveness (r = 0.733), and hardness (r = –0.650) of CR by TA, implying GR of paddy and b* value of CR could be used as indicators for eating quality of rice.     

巢湖藻类组成与环境因子典范对应分析

2008年5月—2009年5月对巢湖藻类组成及水质的季节变化进行了逐月调查研究。鉴定的藻类共6门31属48种,其中绿藻比例最高,占47.9%。藻类优势种群为蓝藻门的铜绿微囊藻（Microcystic aeruginosa）,出现频度为90.9%。3个采样点藻类群落组成没有明显差异,藻类物种丰富度指数（Margalef值）和藻细胞密度的变化范围分别为0.10~1.84和（12.65~825.00）×106 cell.L-1,且冬季值较低。同时,叶绿素（1.30~41.10μg.L-1）和总磷（0.06~0.48 mg.L-1）含量分别在秋季和夏季显著高于其他季节。典范对应分析（CCA）显示,藻类种群分布受水环境因子的影响较为明显。整体上,TP是影响巢湖藻类种群分布的重要因素。     

Sediment Phosphorus Release at Beaver Reservoir, Northwest Arkansas, USA, 2002–2003: A Preliminary Investigation

Phosphorus (P) release from bottom sediments can be a significant source to the overlying water column, potentially maintaining and enhancing algal growth and eutrophic conditions in lakes and reservoirs. Thus, the objectives of this study were to: (1) measure P flux under aerobic and anaerobic conditions from intact sediment cores collected at Beaver Reservoir, northwest Arkansas, (2) evaluate the spatial variability in measured sediment P flux under aerobic and anaerobic conditions along the reservoir, and (3) compare external and internal P loads to Beaver Reservoir. Six intact sediment cores were collected at three sites representing the lacustrine, transitional, and riverine zones during June 2003, September 2003 and February 2004 and incubated for 21 days in the dark at ～22°C. Three cores from each site were incubated under aerobic conditions and anaerobic conditions. Water samples were collected from the overlying water column in each core daily for the first five days and every other day thereafter and analyzed for soluble reactive phosphorus (SRP). Water removed from the core was replaced with filtered lake water, maintaining a constant overlying water volume of 1 l. Sediment P flux under anaerobic conditions (<0.01–1.77 mg m^?2 day^?1) was generally greater than that measured under aerobic conditions (<0.01–0.89 mg m^?2 day^?1). Some spatial variability existed in sediment P flux where P flux was generally greatest at the sites in the riverine and transitional zones. Maximum sediment P flux was observed under anaerobic conditions in cores collected from the transitional zone during September 2003. Average sediment P flux under aerobic conditions (0.09 mg m^?2 day^?1) and anaerobic conditions (0.31 mg m^?2 day^?1) was greater than the external P flux (0.05 mg m^?2 day^?1) estimated from the Beaver Reservoir tributaries. Results showed that the annual internal P load (7 Mg year^?1) from bottom sediments in Beaver Reservoir was less than 10% of the annual external P load (～81 Mg P year^?1). The internal P load was significant, but it would not currently be cost effective to manage this P source given the large surface area of Beaver Reservoir.     

Glyphosate effects on photosynthesis,nutrient accumulation,and nodulation in glyphosate‐resistant soybean

Previous greenhouse studies have demonstrated that photosynthesis in some cultivars of first‐ (GR1) and second‐generation (GR2) glyphosate‐resistant soybean was reduced by glyphosate. The reduction in photosynthesis that resulted from glyphosate might affect nutrient uptake and lead to lower plant biomass production and ultimately reduced grain yield. Therefore, a field study was conducted to determine if glyphosate‐induced damage to soybean (Glycine max L. Merr. cv. Asgrow AG3539) plants observed under controlled greenhouse conditions might occur in the field environment. The present study evaluated photosynthetic rate, nutrient accumulation, nodulation, and biomass production of GR2 soybean receiving different rates of glyphosate (0, 800, 1200, 2400 g a.e. ha^–1) applied at V2, V4, and V6 growth stages. In general, plant damage observed in the field study was similar to that in previous greenhouse studies. Increasing glyphosate rates and applications at later growth stages decreased nutrient accumulation, nodulation, leaf area, and shoot biomass production. Thus, to reduce potential undesirable effects of glyphosate on plant growth, application of the lowest glyphosate rate for weed‐control efficacy at early growth stages (V2 to V4) is suggested as an advantageous practice within current weed control in GR soybean for optimal crop productivity.     

Evaluation of methods of nutrient and water management on tea performance and nutrient loss in the Danjiangkou Reservoir area,China

The long-term control of fertilizer pollution in the Danjiangkou Reservoir is an important task, and promoting good fertilizer pollution control methods is necessary to conserve water quality. A 3-year experiment was conducted to evaluate the fertilizer losses, economic benefits, and feasibility of different nutrient and water management methods in the area. The experiment included the following treatments: (1) local recommended fertilizer dose (450, 144, and 189 kg ha^?1 y^?1 of N, P₂O₅, and K₂O) under rain-fed conditions (CK); (2) chicken manure at 7500 kg ha^–1 without drip irrigation (OF); (3) same dosage of treatment OF but with drip irrigation (OFD); and (4) drip fertigation with 30% of the fertilization dose of CK (DF). The results showed that organic fertilizer and drip fertigation treatments reduced total N (TN) and total P (TP) losses compared to CK due to considerably less amounts of N and P nutrient inputs. Total N runoff losses, and TN and TP concentrations in leaching water did not differ significantly among treatments OF, OFD, and DF. Net income among the CK, OF, and OFD treatments did not differ significantly. Treatment DF resulted in 19.5% and 13.8% more net income than CK and OFD, respectively. Such results provided guidance for promotion to maximize benefits and minimize environmental impacts.     

北方典型水库型水源地水体叶绿素a含量遥感监测研究

遥感监测具有监测区域广、速度快、省时省力等优势,常用于大面积水质监测。其中,叶绿素a浓度是水质监测的一个重要指标。叶绿素a遥感反演的关键是建立遥感数据和叶绿素a含量的定量关系。本文选取石家庄市饮用水源地黄壁庄水库为研究区域,通过进行水体反射光谱现场测量和同步水质采样,得出研究区水体反射光谱特征,并采用丙酮分光光度法测得各水样中叶绿素a含量。在此基础上通过波段比值模型及一阶微分模型分别分析叶绿素a浓度与反射率之间的线性相关性。结果表明,黄壁庄水库各采样点水体叶绿素a浓度均在4.55μg·L-1以下,光谱反射率比值R705nm/R680nm和696 nm反射率的一阶微分值均与叶绿素a浓度有较显著的线性相关性(r2分别为0.736 6和0.875 5)。本文所得结论与方法可为未来对北方水库型水源地水体进行大面积遥感监测叶绿素a含量提供理论参考。     

水口库区流域农业面源污染评价及其防治对策

通过对水口库区流域内18个镇（乡）的农业面源污染源（包括生活污染、人粪尿、农村固体废物及生活垃圾、化肥、畜禽养殖、农田养分流失、村镇地表径流、水产养殖等）调查,并采用等标排放量进行评价,结果显示：2005年该流域全年CODer、TN和TP的排污量分别为6288．87t．4450．07t和1448．82t,总等标排放量为19357．55&#215;10^6m^3,其中CODer、TN和TP的污染率指数分别为2．17％、22．99％和74．85％,故磷和氮是水口库区流域水体污染的主要污染物。污染率指数大小排在前3位的污染源为农田水土流失、水产养殖和畜禽粪尿,分别为41．95％、36．81％和10．60％,三者总和占全流域污染率的89．36％,是该流域农业面源污染的主要污染源。各乡镇间相比较,2005年全年等标排放量以黄田镇居第1位,达2942．14&#215;10^6m^3,污染率指数为15．20％;水口镇和东桥镇次之。不同乡镇的主要污染源有所不同,例如黄墩办、水东办以生活污水为主,炉下镇、大横镇等以畜禽粪尿为主,梅溪镇、东桥镇等以农田养分流失为主,水口镇、尤溪口镇等以水产养殖为主,不同乡镇在治理农业面源污染问题上应各有所侧重。最后提出水口库区流域农业面源污染的防治对策,主要包括：完善农业立法、强化经营管理措施,加强农化物质投入最小化技术研究,开展畜禽粪便多用途综合利用,发展生态农业和有机农业、提倡清洁生产,合理投放鱼饲料和药物、减少流失率。     

Influence of cucurbitacin-containing phytonematicides on selected nutrient elements in leaf tissues of green bean under greenhouse conditions

Cucurbitacin-containing phytonematicides consistently reduce nematode population densities in various crops. However, there is no information on how these products affect the accumulation of essential nutrient elements in crops. The objective of this study was to determine the influence of Nemafric-BL and Nemarioc-AL phytonematicides on accumulation of essential nutrient elements in leaf tissues of green bean (Phaseolus vulgaris L.) under greenhouse conditions. Weekly application of phytonematicides each at 0%, 2%, 4%, 8%, 16% and 32%, were assessed on plant growth variables, nematode suppression and nutrient elements (Ca, K, Na, Fe, Zn) in leaf tissues of green bean at 56 days after initiating the treatments. Phytonematicide concentrations significantly (P?≤?0.05) affected nematode numbers and nutrient elements, without affecting plant growth. Calcium (R²?=?0.97), K (R²?=?0.93), Na (R²?=?0.94) and Fe (R²?=?0.91) each with increasing Nemafric-BL phytonematicide concentration exhibited positive quadratic relations. In contrast, K (R²?=?0.97) and Fe (R²?=?0.98) each with increasing Nemarioc-AL phytonematicide concentration exhibited positive quadratic relations, whereas Na (R²?=?0.92) and Zn (R²?=?0.72) each with increasing phytonematicide concentration exhibited negative quadratic relations. In conclusion, accumulation of essential nutrient elements in green bean leaf tissues and increasing phytonematicide concentrations exhibited density-dependent growth patterns prior to the eventual expression of plant growth responses.