Total Phosphorus Uptake Research Articles

Effect of spacing on P and Zn uptake of local T. Aman rice varieties in Khulna area

A field experiment was conducted at the Agronomy field of Khulna University, Khulna during T. Aman season to evaluate the effects of spacing on nutrient content and total uptake of phosphorus and zinc by grain and straw of traditional rice of Khulna region. The experiment was laid out in split-plot design with three replications assigning three varieties viz., Jotai, Bashfulbalam, Ranisalute and three spacings viz., 30 cm x 30 cm, 40 cm x 40 cm and 50 cm x 50 cm. The variety was assigned in main plot and spacing in sub plot. The plot was fertilized with 40-50-35-5 kg of Urea-TSP-MOP and ZnS04 ha-1 respectively. The results indicated that the single effect of variety and spacing on P and Zn content in grain and straw varied significantly while the straw P content was found insignificant. The interaction effect of variety and spacing on P and Zn content was found significant in all the treatments. The highest P and Zn content of grain was found from the variety Ranisalute at 50 cm x 50 cm (V3S1) but in straw from Ranisalute x 40 cm×40 cm (V3S2) and Bashfulbalam x 30 cm × 30cm (V2S1), respectively. The total uptake of P and Zn was found the highest from Jotai variety at 30 cm x 30 cm spacing. From the interaction it showed that the highest P and Zn uptake was found from Jotai x 30 cm × 30 cm (V1S1) and the lowest from Ranisalute x 50 cm x 50 cm (V3S3). The study indicated that though wider spacings of 40 cm x 40 cm and 50 cm x 50 cm increased the number of tillers hill-1 and nutrient uptake but it cannot increase the nutrient uptake and grain yield ha-1. So, 30 cm x 30 cm spacing showed positive relationship on nutrient uptake than 40 cm x 40 cm and 50 cm x 50 cm spacing.Bangladesh Agron. J. 2014, 17(1): 81-88

Phosphorus uptake by fodder maize (Zea mays L.) under different cadmium levels with or without farm yard manure in loamy sand and clayey soils of Gujarat

A pot experiment was conducted during summer, 2013 by growing fodder maize (Zea mays L.) in loamy sand and clayey soils of Anand and Karvan with five levels of Cd (0.0, 2.5, 5.0, 7.5 and 10.0 ppm) and two levels of FYM (0 and 10 t ha-1) to assess the effect of Cd levels in present of FYM on phosphorus uptake by plant components and total phosphorus uptake by the crop. The result revealed that phosphorus uptake in plant components significantly decreased when 10.0 ppm Cd was added. The total P uptake by maize plant significantly decreased at each level of Cd application. The clayey soil recorded significantly more P uptake as compared to loamy sand soils. The phosphorus removal was significantly higher in FYM treated pot as compared to no FYM application.

Effect of organic and inorganic fertilizer on macronutrients content and uptake of wheat crop under rice- wheat cropping system

The field experiment was conducted in 2004-2005 at the Research Farm of IGAU, Raipur (C.G.) in an on going AICRP on LTFE since 1999, laid out in RBD with ten treatments comprised of 50,100 and 150 per cent of recommended levels of N, P, K and organic sources FYM @ 10t ha-1, green manure (sunhemp in situ), blue green algae @ 10 kg ha-1 and ZnSO4 @ 10 kg ha-1 were applied in Kharif season only. The results showed that the total uptake of nitrogen and phosphorus in treatment T8 (100%NPK+FYM) and potassium and sulphur was recorded with treatment applied 150 per cent NPK (T4 ) of recommended NPK fertilizers.

Optimization of culturing conditions and selection of species for the use of halophytes as biofilter for nutrient-rich saline water

Salt-tolerant plants can be used as biofilters for nutrient-rich saline water such as aquaculture process water. Tripolium pannonicum (Jacq.) Dobrocz. was used to determine optimal culturing conditions for an efficient biofilter performance in terms of nutrient recycling by plant uptake. This performance was evaluated by taking different parameters into account, such as biomass production, plant nitrogen and phosphorus uptake as well as physiological parameters and decrease of nitrate-N and phosphate-P concentrations in the experimental fluid. Afterwards, additional plant species known as edible were studied to follow the idea of generating valuable co-products beside the use as biofilter. It was shown that a nitrate-N concentration of at least 10mgl−1 is necessary for reasonable biomass production. A phosphate-P concentration of 0.3mgl−1 is sufficient, but higher concentrations promote the uptake of phosphate-P. The addition of iron in chelated form is required for the growth of healthy plant biomass; the addition of manganese is beneficial but not implicitly necessary. Salt concentrations lower than seawater salinity promote biomass production and nutrient uptake. The use of a hydroponic culture system is more suitable than sand or expanded clay culture if controlled conditions and nutrient recycling are desired. The five weeks experiment to compare different halophyte species in 0.24m2 tanks with nine plants each resulted in above ground fresh weight of 185 to 398g and total uptake of nitrogen and phosphorus of 0.6 to 2.1g and 0.1 to 0.4g, respectively. All tested species have potential to serve as biofilter and source for valuable co-products. A promising application is the growth of halophytic vegetable plants in marine aquaponic systems.

Inter-Row Subsoiling and Irrigation Increase Starch Potato Yield, Phosphorus Use Efficiency and Quality Parameters

Soil compaction due to the intensive use of heavy machinery is often a problem in potato production. Compaction can limit vertical root growth, water and nutrient uptake, and air and water infiltration, resulting in substantial yield reductions. This study examined the effects of inter-row subsoiling and irrigation on potato yield, tuber quality and phosphorus use efficiency (PUE) in three experiments in southern Sweden on soils with a documented plough pan at 25-30 cm. Potato (Solanum tuberosum L.) was grown in plots treated with inter-row subsoiling to a depth of 55 cm post planting, but prior to the start of root development, or in non-subsoiled plots. In addition, the interaction between inter-row subsoiling and irrigation was investigated under three different irrigation strategies: control (non-irrigated), intensive irrigation and moderate irrigation. Inter-row subsoiling significantly increased average starch yield, phosphorus use efficiency and total uptake of phosphorus in the three experiments. Irrigation significantly increased starch yield and tuber quality. Potato quality was significantly improved by a decrease in the incidence of common scab in the intensive irrigation regime, but the incidence of green tubers increased in the subsoiled plots. No significant interaction between tillage treatment and irrigation strategy was observed.

The effect of effective microorganisms (EM) on EBPR in modified contact stabilization system

Excessive phosphorus can cause eutrophication in water bodies and needs to be reduced in most wastewaters before discharge to receiving waters. The enhanced biological phosphorus removal (EBPR) process has been shown to be an economical and environmentally compatible method for reducing phosphorus from wastewaters. The experiment has been performed in order to investigate the effect of using effective microorganisms (EM) as an application of Enhanced Biological Phosphorous Removal (EBPR) in modified contact stabilization activated sludge system by using contact tank as a phosphorus uptake zone and using thickener tank as a phosphorus release zone. The study involved the construction of a pilot plant which was setup in the Quhafa Wastewater Treatment Plant (WWTP), Al Fayoum, Egypt. Then the uptake and release of total phosphorus were determined through two batch tests using sludge samples from thickener and stabilization tanks. Results showed the removal efficiencies of Chemical Oxygen Demand (COD), Biological Oxygen Demand (BOD5) and total phosphorus (TP) of this pilot plant were 93%, 93% and 90%, respectively. On the other hand the results of batch tests showed that the reason for high ability of phosphorus removal by this pilot plant is related to the high performance of microorganisms for phosphorus accumulation. Finally providing activated EM to the anaerobic zone was to improve fermentation by achieving the enhancement of the performance of phosphorus accumulating organisms (PAOs) and then increase phosphorous release resulting in the decrease of the average effluent phosphorus concentration.

Investigation of initial pH effects on growth of an oleaginous microalgae Chlorella sp. HQ for lipid production and nutrient uptake

Using microalgae for synchronous biodiesel production and wastewater treatment is a promising technology. The growth, lipid accumulation and nutrient uptake characteristics of an oleaginous microalga Chlorella sp. HQ were evaluated at different initial pH from 5.0 to 11.0. The pH values changed towards neutrality and ended in the range 6.0-9.0 without artificial control. The alkalinity change before 8 days was in accordance with pH changing. The alkalinity increase after 8 days might be due to the nitrate consumption, CO2 absorption and the algal release at stationary phases. The algal maximal cell density and population growth rate increased with initial pH values while the specific growth rate kept high without significant difference. After 30 days, the maximal algal lipid yield reaching 167.5 mg · L(-1) occurred at initial pH of 7.0 and the triacylglycerols content was significantly enhanced to 63.0% at initial pH of 5.0 but with a peak of 54.4 mg · L(-1) at initial pH of 9.0. Furthermore, nutrients were taken up by the alga obviously at all initial pH values. The total nitrogen (TN) and total phosphorus (TP) uptake efficiencies in neutral/alkalic circumstances were larger than that in acid circumstance. The TN and TP were removed by 87.77% and 92.05%, respectively, at initial pH of 7.0.

Fate and removal of nutrients in bioretention systems

Phosphorus and nitrogen in different forms are the primary concern in surface water bodies nowadays since it causes eutrophication. A bioretention system, an example of green stormwater infrastructures reduces nutrients through biological processes such as plant uptake and microbial conversion of nitrogen known as bioremediation. In this study, the performance of two types of bioretention system in managing nutrients from urban stormwater runoff was investigated. Total phosphorus (TP) was reduced by 85% up to 86% in both bioretention types while total nitrogen (TN) was reduced by 49 and 55% in type A and type B bioretention, respectively. Among the plants species used in the study, Rhododendron indicum Linnaeus was identified as the most appropriate plant that should be used in bioretention systems considering factors such as number of flower per plants, plant decay rate, cost of plant, number of plant per reactor, and TN and TP uptake by plants. Based on the results, 25–32% of TN and 47–59% of the TP load were absorbed by the soil medium. This finding signified that filtration was the main removal mechanism for nutrients in bioretention.

Bioresource Nutrient Recycling and Its Relationship with Biofertility Indicators of Soil Health and Nutrient Dynamics in Rice–Wheat Cropping System

A field experiment was conducted for 3 years during 2006–2009 in India to study the effects of plant nutrient recycling through crop residue management, green manuring, and fertility levels on yield attributes, crop productivity, nutrient uptake, and biofertility indicators of soil health in a rice–wheat cropping system. The study revealed that soil microbial biomass carbon (SMBC) and carbon dioxide (CO2) evolution were significantly greatest under crop residue incorporation (CRI) + Sesbania green manuring (SGM) treatment and were found at levels of 364 μg g−1 soil and 1.75 μg g−1 soil h−1, respectively; these were increased significantly by recycling of organic residues. Activities of dehydrogenase and phosphatase enzymes increased significantly after 3 years, with maximum activity under CRI + SGM treatment. The CRI with or without SGM significantly influenced the plant height, number of tillers m−2, number of grains panicle−1 or ear−1, and 1000-grain weight. Mean yield data of rice and wheat revealed that CRI or crop residue burning (CRB) resulted in slightly greater yield over crop residue removal (CRR) treatment. The CRI + SGM treatment again observed significantly greatest grain yields of 7.54 and 5.84 t ha−1 and straw yields of 8.42 and 6.36 t ha−1 in rice and wheat, respectively, over other crop residue management treatments. Total nitrogen (N), phosphorus (P) and potassium (K) uptake in rice–wheat system was greatest with amounts of 206.7, 37.2, and 205.6 kg ha−1, respectively, in CRI + SGM treatment. Fertility levels significantly influenced the rice and wheat yield with greatest grain yields of 6.66 and 5.68 t ha−1 and straw yields of 7.94 and 5.89 t ha−1 in rice and wheat, respectively, with the application of 150% of recommended NPK. Total NPK uptake in rice–wheat system also increased significantly with increase in fertility levels with greatest magnitude by supplying 150% of recommended NPK. Overall, nutrient recycling through incorporation of crop residues and Sesbania green manuring along with inorganics greatly improved the crop productivity, nutrient uptake, and biofertility indicators of soil health with substantial influence on SMBC, CO2 evolution, and dehydrogenase and phosphatase enzyme activities. This indicates that crop residue management along with Sesbania green manuring practice could be a better option for nutrient recycling to sustain the crop productivity and soil health in intensive rice–wheat cropping system in India as well as in similar global agroecological situations, especially in China, Pakistan, and Bangladesh.

Interactive Effect of Soil Salinity and Copper Application on Growth and Chemical Composition of Pistachio Seedlings (cv. Badami)

The effects of five salinity levels and four Cu levels on growth and chemical composition of Badami pistachio seedlings were studied under greenhouse conditions in a completely randomized design with three replications. Growth parameters were determined on the 24th week after planting. Total elemental uptake amounts in shoot and root of plant were measured. Results showed that salinity decreased leaf area, stem height, and shoot and root dry weights. Application of 2.5 and 5 mg copper (Cu) kg−1 soil significantly increased root dry weight, whereas it had no significant effects on shoot dry weight and leaf area. Application of 7.5 mg Cu kg−1 soil had a negative effect on stem height. Salinity declined shoot and root total Cu and phosphorus (P) uptake amounts but increased shoot and root total sodium (Na) and chlorine (Cl) uptake amounts. Copper increased shoot and root total Cu uptake amounts, root total P uptake, and shoot total Na uptake but decreased shoot total Cl uptake.

Application of contact stabilization activated sludge for enhancing biological phosphorus removal (EBPR) in domestic wastewater

The experiment has been performed in order to investigate the effect of using contact stabilization activated sludge as an application of enhancing biological phosphorous removal (EBPR) by using contact tank as a phosphorus uptake zone and using thickening tank as a phosphorus release zone. The study involved the construction of a pilot plant which was setup in Quhafa waste water treatment plant (WWTP) that included contact, final sedimentation, stabilization and thickening tanks, respectively with two returns sludge in this system one of them to contact tank and another to stabilization tank. Then observation of the uptake and release of total phosphorus by achievement through two batch test using sludge samples from thickener and final sedimentations. Results showed the removal efficiencies of COD, BOD and TP for this pilot plant with the range of 94%, 85.44% and 80.54%, respectively. On the other hand the results of batch tests showed that the reason of high ability of phosphorus removal for this pilot plant related to the high performance of microorganisms for phosphorus accumulating. Finally the mechanism of this pilot plant depends on the removal of the phosphorus from the domestic waste water as a concentrated TP solution from the supernatant above the thickening zone not through waste sludge like traditional systems.

The use of <sup>32</sup>P Method to Evaluate the Growth of Lowland Rice Cultivated in a System of Rice Intensification (SRI)

A pot experiment has been conducted to evaluate the growth of the Dyah Suci, a lowland rice variety, in an SRI (System of Rice Intensification) planting system. The phosphorus-32 ( 32 P) isotope technique was used to evaluate the growth of plants in relation with their phosphorus uptake. The uptake was assumed to vary in the same direction as the growth of the plant. The 32 P uptake is assumed to vary in the opposite direction to the plant’s total phosphorus uptake. Here the 32 P uptake is expressed in count per minutes (cpm) which is then transformed to disintegration per minute (dpm). The results show that , in terms of promoting the plant’s uptake of phosphorus, the SRI planting system is superior to the conventional planting system, and it i s manifested in the higher dry weight of straw and grain. From this experiment it is concluded that the 32 P method can be used satisfactorily as a tool for explaining the relation between P-uptake and plant growth . Received: 04 Juny 2013; Revised: 22 August 2013; Accepted: 30 August 2013

Influence of cetyltrimethyl ammonium bromide on nutrient uptake and cell responses of Chlorella vulgaris

The removal of nutrients by algae is regarded as a vital process in wastewater treatment, however algal cell activity can be inhibited by some toxic chemicals during the biological process. This study investigated the uptake of ammonia nitrogen (NH4+) and total phosphorus (TP) by a green alga (Chlorella vulgaris) and algal cell responses under the stress of cetyltrimethyl ammonium bromide (CTAB), a representative for quaternary ammonium compounds (QACs, cationic surfactants). When the concentration of CTAB increased from 0 to 0.6mg/L, the uptake efficiencies of NH4+ and TP decreased from 88% to 18% and from 96% to 15%, respectively. Algal cell responses showed a decline in photosynthesis activity as indicated by the increase of chlorophyll autofluorescence from 2.9a.u. to 25.3a.u.; and a decrease of cell viability from 88% to 51%; and also a drop in esterase activity as indicated by the decrease in fluorescence of fluorescein diacetate stained cells from 71.5a.u. to 4.7a.u. Additionally, a transcription and translation response was confirmed by an enhancement of PO peak and amide II peak in algal cellular macromolecular composition stimulated by CTAB. The results suggest that QACs in wastewater may inhibit nutrient uptake by algae significantly through declining algal cell activities.

Arsenic uptake in upland rice inoculated with a combination or single arbuscular mycorrhizal fungi

A pot trial was conducted to investigate the role of arbuscular mycorrhizal fungi (AMF) on arsenic (As) uptake of upland rice (Oryza sativa L.) cultivar, Zhonghan 221; where the following 3 species of Glomus geosporum (Gg), G. mosseae (Gm) and G. versiforme (Gv) were applied as single or combined inoculations. In general, Gm significantly enhanced (p<0.05) total As concentration in Zhonghan 221 when compared to the non mycorrhizal (NM) treatment. The treatment inoculated with Gg+Gm increased total phosphorus (P) uptake and decreased total As uptake in the ingestible rice parts (husks and grains). In terms of AMF colonization rates, Gm had significantly higher (p<0.05) average values of 57.3% and 66.6% when grown in As0 and As40 soils, respectively, in comparison to that of Gg and Gv, and finally dropped to 3.63% when grown in As80 soil. There was a significant difference (p<0.05) between single AMF species (Gg or Gv) and AMF mixture treatments (Gg+Gv, Gg+Gm, Gv+Gm and Gg+Gv+Gm) in terms of total As concentrations in rice. No significant correlation between AMF colonization rates and As uptake in grains (r=0.150, p>0.01) and total P (r=0.002, p>0.01) were observed.

Improvement of biological total phosphorus release and uptake by low electrical current application in lab-scale bio-electrochemical reactors

The overall process enhancement by different electrical current application on the biological phosphorus release and uptake have been investigated. Five reactors were constructed for three experiments and activated sludge was used as inoculums. In Exp.1 by comparing the control and the bio-electrochemical reactors, it was found that the overall phosphorus removal efficiency could be enhanced at lower electrical current applications of 5mA and 10mA, but were restrained at higher than 20mA, although 20mA could be a sensitive turning point. Moreover, the electrochemical effects of the cathodic and the anodic reactions on the phosphorus release and uptake, respectively, have been further evaluated separately under an electrical current application of 10mA in Exp.2 and Exp.3, respectively. As observed, both of the biological release and uptake were improved by the cathodic reactions in the cathode reactor, but not by the anodic reactions in the anode reactor, and thus indicated that the cathodic reactions play an important role in the improvement of the biological phosphorus release and uptake.

Response of Soybean [Glycine max (L.) Merrill] to Sources and Levels of Phosphorus

A field experiment was conducted during rainy seasons of 2007-2009 in India (Manipur) to study the effect of different sources and levels of phosphorus on productivity of soybean [Glycine max (L.) Merrill]. The treatments consisted of four sources of phosphorus [Single super phosphate (SSP), Di-ammonium phosphate (DAP), Single super phosphate (SSP)+Phosphate solubilizing bacteria (PSB), Di-ammonium phosphate (DAP)+Phosphate solubilizing bacteria (PSB)], four levels of phosphorus (20, 40, 60 and 80 kg P2O5 ha-1) and one absolute control(without any fertilizer and PSB). Application of SSP+PSB produced significantly higher number of nodules per plant, dry weight of nodules per plant, number of pods per plant and 100-seed weight than the other treatments. Maximum grain yield and total phosphorus uptake were also recorded when using SSP+PSB. Yield attributing characters, grain and stover yield were increased with increasing levels of phosphorus. Regarding evaluation of various efficiency fractions of soybean, agronomic efficiency, physiological efficiency and phosphorus use efficiency had more pronounced effects on combined application of SSP+PSB. However, apparent recovery of phosphorus was higher in DAP+PSB due to higher stover yield and higher phosphorus uptake. Among the different levels the efficiency fractions increase up to 60 kg P2O5 ha-1 and declined at 80 kg P2O5 ha-1.

The effect of multi-component fertilizers on spring triticale yield, the content and uptake of macronutrients

Fertilization is the main factor and an indicator of the effectiveness of agricultural production. A wide variety and range of mineral fertilizers are currently available on the Polish market. They differ with respect to quality and price, while their names are often similar, which makes it difficult for the farmer to select the best one. There has been a steady increase in the share of multi-component fertilizers in total mineral fertilizer consumption in Poland, which seems very positive. Multi-component fertilizers supply a combination of nutrients at a time, in adequate amounts and proportions, in view of the content of available phosphorus, potassium and magnesium in the soil. The objective of this study was to determine the effect of mixed multi-component fertilizers on spring triticale yield, the content and uptake of macronutrients. A three-year field experiment (2005-2007) was carried out in a randomized block design at the Research and Experimental Station in Tomaszkowo, at the University of Warmia and Mazury in Olsztyn. The experiment comprised three fertilization treatments: control treatment (simple fertilizers) and two treatments with mixed multi-component fertilizers, Amofosmag 4 (NPKMg 4:15:15:2) and Amofosmag 3 (NPKMg 3:14:20:2). The tested crop was spring triticale (Triticosecale Wittm) cv. Wanad. Amofosmag 4 had the most beneficial influence on the yield of spring triticale grain, which increased by 11% on average, compared with the control treatment. The effect of Amofosmag 3 was similar to that of simple fertilizers. Simple and multi-component fertilizers exerted a comparable effect on the mineral composition of triticale grain and straw, which remained within normal limits. More pronounced differences were observed in this respect between successive years of the study. The highest total uptake of nitrogen, phosphorus, potassium, calcium and magnesium by spring triticale was noted in plots fertilized with

Effect of Arbuscular Mycorrhizal Inoculations on Seedling Growth and Biomass Productivity of Two Bamboo Species

A study was conducted to identify suitable arbuscular mycorrhizal (AM) fungi for inoculation of Bambusa bambos and Dendrocalamus strictus at nursery stage for increasing growth and productivity. Twelve AM species, isolated from bamboo and other common trees of Bundelkhand were used for inoculations. In B. bambos, total dry weight and phosphorus (P) uptake were significantly increased by all studied fungi and shoot length was increased by eight AM inoculants. Maximum mycorrhizal dependency (MD) was recorded for Acaulospora scrobiculata (44.2%), followed by Glomus cerebriforme (41.6%) and G. intraradix (41.0%). In D. strictus, all tested AM inoculants significantly increased shoot length, dry shoot weight and P uptake, except Glomus 1. Dry root weight was significantly increased by only two inoculants namely, G. cerebriforme and G. etunicatum. Total dry weight was significantly increased by eight AM fungi. Maximum MD was recorded for G. cerebriforme (62.9%), followed by G. diaphanum (55.0%) and G. etunicatum (51.3%). Thus, the results showed that utilization of effective AM fungi can enhance the productivity of bamboo in the region.

TOTAL PHOSPHORUS REMOVAL FROM DOMESTIC WASTEWATER WITH CYPERUS ALTERNIFOLIUS IN VERTICAL-FLOW CONSTRUCTED WETLANDS AT THE MICROCOSM LEVEL

Vertical-flow constructed wetland (VFCW) is an effective alternative for removal of nutrients, heavy metals, and organic pollutants from wastewaters. This study investigated the uptake and removal of total phosphorus (TP) by Cyperus alternifolius from domestic wastewaters in the simulated VFCWs. The total of eight simulated VFCW treatments, including two different substrates, two different wet-to-dry ratios, and with and without C. alternifolius species (2 × 2 × 2 = 8), were utilized for an operation period of two years in this study. Results show that about 1.1 to 1.4 times more TP was removed from the influent with the presence of C. alternifolius as compared to without this plant species. A linear correlation existed between the aboveground biomass and its TP content. An increase in total biomass by 1000 g would result in an increase in TP accumulation in the aboveground biomass by 4.9g. Large amounts of TP were removed by the substrate adsorption as compared to those by the aboveground biomass. Results suggest that, although substrate adsorption played a major role in TP removal, C. alternifolius uptake was an alternative pathway for further removal of TP from wastewaters in the VFCWs.

Numerical analysis of the performance of horizontal and wavy subsurface flow constructed wetlands

A three-dimensional numerical model is proposed for modeling the TP transport in the Horizontal Subsurface Flow (HSSF) and Wavy subsurface Flow (WSSF) constructed wetland in this article. Both numerical simulations and physical experiments indicate that the removal efficiency of WSSF is higher than that of HSSF. The difference of performance in removing pollutants, e.g., Total Phosphorus (TP), between HSSF and WSSF is numerically analyzed from three interactive aspects, that is, the hydraulic behavior, the substrate and the plant roots. It is shown that the dead zone volume in WSSF is smaller than in HSSF with less short circuiting. The soil in the top layer is more used in WSSF than in HSSF. The TP uptake by the plant roots in WSSF is higher than that in HSSF.