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1.
Effects of soil organic matter (80M) on P sorption of soils still remain to be clarified because contradictory results have been reported in the literature. In the present study, pH-dependent P sorption on an allophanic Andisol and an alluvial soil was compared with that on hydrogen peroxide (H202)-treated, acid-oxalate (OX)-treated, and dithionite-citrate- bicarbonate (DCB)-treated soils. Removal of 80M increased or decreased P sorption depending on the equilibrium pH values and soil types. In the H2O2 OX-, and DCB-treated soils, P sorption was pH-dependent, but this trend was not conspicuous in the untreated soils. It is likely that 80M affects P sorption of soils through three factors, competitive sorption, inhibition of polymerization and crystallization of metals such as AI and Fe, and flexible structure of metal-80M complexes. As a result, the number of available sites for P sorption would remain relatively constant in the wide range of equilibrium pH values in the presence of 80M. The P sorption characteristics were analyzed at constant equilibrium pH values (4.0 to 7.0) using the Langmuir equation as a local isotherm. The maximum number of available sites for P sorption (Q max) was pH-dependent in the H202-, OX-, and DCBtreated soils, while this trend was not conspicuous in the untreated soils. Affinity constants related to binding strength (K) were less affected by the equilibrium pH values, soil types, and soil treatments, and were almost constant (log K ≈ 4.5). These findings support the hypothesis that 80M plays a role in keeping the number of available sites for P sorption relatively constant but does not affect the P sorption affinity. By estimating the Q max and K values as a function of equilibrium pH values, pH-dependent P sorption was well simulated with four or two adjustable parameters. This empirical model could be useful and convenient for a rough estimation of the pH-dependent P sorption of soils. 相似文献
2.
HU Guo-Song 《土壤圈》1996,6(3):251-258
The kinetics of H+ releasing after Pb2+ adsorption was studied by the potentiometric method combined with the acid-base titration curve technique. Results showed that pH of latosol, red soil and kaolinite suspensions dropped sharply, and then decreased gradually. Most of the H+ exchanged, more than 60%, was displaced at the first minute after Pb2+ was added into the suspension. More H+ was released at a higher concentration of Pb2+ added for a given sample and the amount of H+ released decreased in the order of red soil > latosol > kaolinite at a given concentration. The time-dependent data of H+ releasing of latosol, red soil and kaolinite at two concentrations could be fitted best with the second-order equation among the six equations, including second-order equation, two-constant equation, Elovich equation, parabolic diffusion equation, first-order equation and exponential equation. The H+/Pb2+ exchange stoichiometry increased with time, and a stable ratio of H+/Pb2+, being 1.73, 1.92 and 2.01 for kaolinite, latosol and red soil, respectively, was reached 25 minutes later. 相似文献
3.
Soil salinity is a concern in the wake of climate change challenges due to rising sea levels and coastal salinity in Papua New Guinea. A greenhouse experiment was conducted in Split Plot design, with five elite sweet potato genotypes (main-plot factors) and three levels of sodium chlroide (NaCl) concentrations (sub-plot factors) replicated six times. The vine cuttings of genotype RAB 45 showed very low mortality percentage (33%) at 600 mM NaCl concentration. At salinity level of 200 mM NaCl, aerial dry biomass of the genotypes was inversely but significantly (r = –0.40; p < 0.05) related to the accumulation of sodium (Na+) in the tissues. The Na+ accumulation in the tissues was antagonistic to the potassium (K+) and calcium (Ca2+) ions. Among the sweetpotato genotypes, Na+/K+ ratio decreased in the following order: RAB 45> KAV 11 > Northern Star > DOY 2 > L 46, which was more or less corroborated with the trend in the aerial dry matter. 相似文献
4.
Abstract The phosphate sorption (P sor) capacity of soils increased when the soils were reduced (Willet and Higgins, Aust. J. Soil Res., 16, 319–326, 1978). The present study aimed at the elucidation of this mechanism using Na2S2O4 and 5 different soils. The P sor of the 5 soils increased with the addition of a small amount of Na2S2O4. Fe(II) was released from the soils with the addition of the same small amount of Na2S2O4. Furthermore, when the amount of FeCl2 corresponding to the amount of Fe(II) released along with the small amount of Na2S2O4 was added, the P sor of the soil increased. However, the P sor of the lowland soils, of which the hydrous Fe oxide content was lower than the others, decreased when the amount of Na2S2O4 addition was increased up to 150–200 g kg?1. Based on these results, the following process is inferred for the increase in the P sor of the soils when they are reduced. Hydrous Fe oxide in soil takes the form of very fine, high-density particles and reacts with P mainly on their surface. When a small amount of Na2S2O4 is added, the hydrous Fe oxide is partially reduced, dissolved and finally re-precipitates with P by oxidation with O2 from the air during the experiment. 相似文献
5.
Carlos Alberto Bucker Sonia Regina de Souza Manlio Silvestre Fernandes 《Journal of plant nutrition》2013,36(3):485-496
The effects of fusicoccin or vanadate on proton (H+) extrusion and potassium (K) uptake of four varieties of rice (oryza satiya L.) were studied. Two of them were improved varieties (IAC-47 and Agulha), with 70% genetic similarity. The two others were landraces (Bico Ganga and Piaui). Vanadate totally blocked H+-pumping activity while fusicoccin increased it. Potassium uptake was suppressed under vanadate but increased sharply under the fusicoccin treatment. The Piaui was the most affected by fusicoccin, while Agulha was the least affected. Under fusicoccin, Bico Ganga had a 48% increase in K uptake at the end of the experimental period in relation to the controls, while IAC-47 showed only a 17% increase. Taken together, for all varieties and treatments, there was a negative correlation between the final pH and the total K taken up by plants. This study suggests that some rice varieties need additional stimulation from external sources to express their full H+-pumping and K-uptake capabilities. 相似文献
6.
Georg J. Lair Martin H. Gerzabek Georg Haberhauer Michael Jakusch Holger Kirchmann 《植物养料与土壤学杂志》2006,169(1):60-68
This study investigated the effect of different farming practices over long time periods on the sorption‐desorption behavior of Cu, Cd, and Zn in soils. Various amendments in a long‐term field experiment over 44 y altered the chemical and physical properties of the soil. Adsorption isotherms obtained from batch sorption experiments with Cu, Cd, and Zn were well described by Freundlich equations for adsorption and desorption. The data showed that Cu was adsorbed in high amounts, followed by Zn and Cd. In most treatments, Cd ions were more weakly sorbed than Cu or Zn. Generally, adsorption coefficients KF increased among the investigated farming practices in the following order: sewage sludge ≤ fallow < inorganic fertilizer without N ≈ green manure < peat < Ca(NO3)2 < animal manure ≤ grassland/extensive pasture. The impact of different soil management on the sorption properties of agricultural soils for trace metals was quantified. Results demonstrated that the soil pH was the main factor controlling the behavior of heavy metals in soil altered through management. Furthermore, the constants KF and n of isotherms obtained from the experiments significantly correlated with the amount of solid and water‐soluble organic carbon (WSOC) in the soils. Higher soil pH and higher contents of soil organic carbon led to higher adsorption. Carboxyl and carbonyl groups as well as WSOC significantly influenced the sorption behavior of heavy metals in soils with similar mineral soil constituents. 相似文献
7.
《Communications in Soil Science and Plant Analysis》2012,43(11):927-943
Abstract Release of native and added K+ and NH+ 4 from two soils was monitored during a 166 day incubation/leaching experiment. One soil (Brookston) represented a major soil series In Ontario whereas the other (Harriston) was suspected having a relatively large fixation capacity. Treatments were imposed involving addition of 50 μM g‐1 soil of K+(KCl) or NH+ 4 (NH4Cl) only or one added after the other on successive days. The addition of either K+ or NH+ 4 on day 2 tended to inhibit the release of the other added on day I. Also the addition of either K+ or NH+ 4 on day 1 tended to inhibit the sorption or fixation of the other on day 2. The release rate of K+ during the 10 to 166 day period was almost constant and not affected by the addition of NH+ 4. Alternatively, the addition of K+ on day 2 slowed the release rate of NH+ 4 measured by NO? 3 appearance from day 10 to 40 but had no effect thereafter. At the end of the experiment considerably more K+ than NH+ 4 was retained suggesting that K+ was more firmly fixed. However, the continuing nitrification of NH+ 4 must be contrasted with periodic removal of K+ by leaching with 0.01 M CaCl2 solution since the equilibrium between exchangeable and fixed ions was affected. There were no notable differences between the two soils inspite of a considerable difference in clay content. 相似文献
8.
《Communications in Soil Science and Plant Analysis》2012,43(17-18):2663-2677
Accurate estimation of the available potassium (K+) supplied by calcareous soils in arid and semi‐arid regions is becoming more important. Exchangeable K+, determined by ammonium acetate (NH4OAc), might not be the best predictor of the soil K+ available to crops in soils containing micaceous minerals. The effectiveness of different extraction methods for the prediction of K‐supplying capacities and quantity–intensity relationships was studied in 10 calcareous soils in western Iran. Total K+ uptake by wheat grown in the greenhouse was used to measure plant‐available soil K+. The following methods extracted increasingly higher average amounts of soil K+: 0.025 M H2SO4 (45 mg K+ kg?1), 1 M NaCl (92 mg K+ kg?1), 0.01 M CaCl2 (104 mg K+ kg?1), 0.1 M BaCl2 (126 mg K+ kg?1), and 1 M NH4OAc (312 mg K+ kg?1). Potassium extracted by 0.01 M CaCl2, 1 M NaCl, 0.1 M BaCl2, and 0.025 M H2SO4 showed higher correlation with K+ uptake by the crop (P < 0.01) than did NH4OAc (P < 0.05), which is used to extract K+ in the soils of the studied area. There were significant correlations among exchangeable K+ adsorbed on the planar surfaces of soils (labile K+) and K+ plant uptake and K+ extracted by all extractants. It would appear that both 0.01 M CaCl2 and 1 M NaCl extractants and labile K+ may provide the most useful prediction of K+ uptake by plants in these calcareous soils containing micaceous minerals. 相似文献
9.
土壤组分对广东省酸性水稻土磷吸附参数的影响 总被引:9,自引:2,他引:7
Soil components affecting phosphate sorption parameters were studied using acid paddy soils derived from basalt, granite, sand-shale and the Pearl River Delta sediments, respectively, in Guangdong Province.For each soil, seven 2.50 g subsamples were equilibrated with 50 mL 0.02 mol L-1 (pH=7.0) of KCl containing 0, 5, 10, 15, 25, 50 and 100 ng P kg-1, respectively, in order to derive P sorption parameters (P sorption maximum, P sorption intensity factor and maximum buffer capacity) by Langmuir isotherm equation. It was shown that the main soil components influencing phosphate sorption maximum (Xm) included soil clay, pH,amorphous iron oxide (Feo) and amorphous aluminum oxide (Alo), with their effects in the order of Alo >Feo > pH > clay. Among these components, pH had a negative effect, and the others had a positive effect.Organic matter (OM) was the only soil component influencing P sorption intensity factor (K). The main components influencing maximum phosphate buffer capacity (MBC) consisted of soil clay, OM, pH, Feo and Alo, with their effects in the order of Alo > OM > pH > Feo > clay. Path analysis indicated that among the components with positive effects on maximum phosphate buffer capacity (MBC), the effect was in the order of Alo > Feo > Clay, while among the components with negative effects, OM > pH. OM played an important role in mobilizing phosphate in acid paddy soils mainly through decreasing the sorption intensity of phosphate by soil particles. 相似文献
10.
Geochemical sorption and biological demand control phosphorus (P) retention and availability in soils. Sorption and the biota predominantly utilize the same inorganic form of P, from the same soil pool, on the same time scale, and thus are likely to compete for P as it flows through the available pool. In tropical soils, P availability is typically quite low and soil geochemical reactivity can be quite high. We tested whether greater P sorption strength in tropical soils resulted in lower biological uptake of available P. Since the strength of soil sorption and biological demand for P change as ecosystems develop and soils age, we used soils from the two upper horizons from three sites along a 4.1 million-year-old tropical forest chronosequence in the Hawaiian archipelago. We evaluated the strength of geochemical sorption, microbial demand, and the partitioning of added available P into biological versus geochemical soil pools over 48 h using a 32PO4 tracer. Soil sorption strength was high and correlated with soil mineral content. The amount of added phosphate geochemically sorbed versus immobilized by microbes varied more between the organic and mineral soil horizons than among soil ages. Microbial activity was a good predictor of how much available P was partitioned into biological versus geochemical pools across all soils, while sorption capacity was not. This suggests that microbial demand was the predominant control over partitioning of available P despite changes in soil sorption strength. 相似文献
11.
Nitrogen (N), ammonium (NH4+) and nitrate (NO3?), is one of the key determinants for plant growth. The interaction of both ions displays a significant effect on their uptake in some species. In the current study, net fluxes of NH4+ and NO3? along the roots of Picea asperata were determined using a Non-invasive Micro-test Technology (NMT). Besides, we examined the interaction of NH4+ and NO3? on the fluxes of both ions, and the plasma membrane (PM) H+-ATPases and nitrate reductase (NR) were taken into account as well. The results demonstrated that the maximal net NH4+ and NO3? influxes were detected at 13–15?mm and 8–10.5?mm from the root apex, respectively. Net NH4+ influx was significantly stimulated with the presence of NO3?, whereas NH4+ exhibited a markedly negative effect on NO3? uptake in the roots of P. asperata. Also, our results indicated that PM H+-ATPases and NR play a key role in the control of N uptake. 相似文献
12.
《Communications in Soil Science and Plant Analysis》2012,43(7):1242-1258
Phosphate (Pi), the fully oxidized and assimilated form of phosphorus (P), influences virtually all developmental and biochemical processes in plants; however, its availability and distribution are widely heterogeneous. Paradoxically, although total P is abundant in lithosphere, elusive soil chemistry of Pi renders the element the most dilute and the least mobile in natural and agricultural ecosystems, resulting in P deprivation due to its low mobility and high fixation capacity in the soil. Nonmycorrhizal Brassica does not produce specialized cluster/dauciform roots but is an effective P user compared to other crops. Using a soil low in P (Mehlich 3–extractable P) with or without P fertilization, Brassica cultivars showed substantial genetic diversity in P-utilization efficiency (PUE), P efficiency (PE), P-efficiency ratio (PER), and P-stress factor (PSF). Cultivars producing greater root biomass accumulated greater total P contents, which in turn was related negatively to PSF and positively to shoot and total biomass. Plant survival and reproduction rely on efficient strategies in exploring culture media for P. Acquisition of orthophosphate from extracellular sparse P sources may be enhanced by biochemical rescue strategies such as copious H+ efflux and/or carboxylates exudation into rhizosphere by roots via plasmalemma H+-ATPase and anion channels triggered by P starvation. The P-starvation-induced solution pH changes due to H+ efflux, and carboxylates exudations were estimated by low-P-tolerant and low-P-sensitive cultivars in solution culture experiments. Low-P-tolerant cultivars showed more decrease in pH compared to low-P-sensitive cultivars when cultivars were grown under a P-stress environment induced by using sparingly soluble P sources (rock phosphate and tricalcium phosphate). The P contents of cultivars were inversely related to decrease in culture media pH. Low P-tolerant cultivars presented enhanced H+-efflux and total carboxylates exudations compared to low-P-sensitive cultivars, resulting in more rhizosphere acidification to scavenge Pi, evidencing their adaptability to P starvation. These elegant P-stress-induced rescue strategies by tested cultivars provided the basis of enhanced P solubilization and acquisition of P from sparingly soluble P sources to combat P-starved environments. 相似文献
13.
This study investigated phosphorus sorption kinetics of three different soils from three sites within the Sahel region of Tunisia; iso-humic soils from Chott-Mariem site, calcic-magnesic soils from Enfidha site and saline-sodic soils from Kondar site. Soils from all sites were sampled (0–25 cm) and analysed for their physico-chemical proprieties. In previous works, we determined the adsorption efficiency of these different soils. In this study, we focused on the influence of contact time on phosphorus adsorption by the different soils. The analytic data were approached from the following kinetics models: pseudo-first-order, pseudo- second-order and Elovich model. The second order model was shown to be the best fit for describing phosphorus adsorption by each soil sample, as seen from the correlation coefficient R2 which ranged from 0.68 to 0.96 for the pseudo-first-order model, 0.91 to 0.99 for pseudo-second-order model and 0.84 to 0.94 for Elovich model. 相似文献
14.
Hitoshi Obata Noriyuki Inoue Motoaki Matsuoka Masanao Umebayashi 《Soil Science and Plant Nutrition》2013,59(2):439-442
As a result of Cd treatment, K concentrations decreased in Cd sensItive maize and kidney bean calli (Obata et al. 1994) and in intact roots of kidney bean plants (Obata et al. unpublished). Potassium may be extruded from the roots or the absorption of K may be depressed by the Cd treatment in these Cd sensitive plants. Obata et al. (1996) observed that Cd inhibited both the efflux of H+ and influx of K+ following K+ addition in intact roots of bean. Thus Cd may affect the activity of proteins essential to ion movement., i.e. ioncarriers, channels and ATPase embedded in the membranes and/or may affect the permeability of the lipids of the membrane. 相似文献
15.
《Communications in Soil Science and Plant Analysis》2012,43(5-6):351-363
Abstract Studies with 42 soils selected to obtain a wide range in properties showed that air‐dry and moist soils have substantial capacities for sorption of H2S from air (averages, 9.8 and 12.5 g S kg‐1 soil, respectively). Soil properties influencing the capacities of air‐dry soils for sorption of H2S included sand and clay contents, DCB‐soluble Mn, exchangeable Na, DCB‐soluble Fe, and total DCB‐soluble metals. The corresponding capacities of moist soils were influenced by sand and clay contents, DCB‐soluble Mn, and surface area. It was possible to closely predict the H2S sorption capacities of both air‐dry and moist soils (R2 = 0.804 and 0.918, respectively) from consideration of their properties. 相似文献
16.
Abbas Samadi 《Archives of Agronomy and Soil Science》2013,59(1):29-37
Determining potassium (K) fertilizer requirement using sorption isotherms is considered more accurate than conventional soil K tests. A total of 59 surface soil samples were used to establish K exchange isotherm. To evaluate K requirement sorption test, a glasshouse experiment using perennial ryegrass (Lolium perenne, cv. Roper) was carried out on 10 soil samples. The experiment was laid out as a completely randomized design with four replications and four K levels (K0, K20, K40, K80). Concentrations of K in solution established by adding K in the pots estimated from the sorption curve ranged from 20 to 80 mg K l?1 including check treatment (no K). Dry matter yield of ryegrass in most soils approached maximum as adjusted K levels were increased to 20 mg K l?1. The amounts of K required to bring the soils to 20 mg l?1 in soil solution varied among soils and ranged from 99 to 399 mg kg?1, on average 205 mg kg?1 soil. It was found that a useful regression model for the prediction of standard K requirement (K20) included the combination of plant available K extracted by NH4OAc (Av-K) and clay content: K20 = ?41 ? 0.63 Av-K + 9.0 Clay (R2 = 0.61, p < 0.001, n = 59). 相似文献
17.
Mohammad E. Hossain Sirajul Hoque Khan T. Osman 《Archives of Agronomy and Soil Science》2013,59(9):959-966
An experiment was conducted to observe the phosphate sorption potential of some soils of Bangladesh. Three soil series of calcareous origin, namely Sara (Aquic Eutrochrept), Gopalpur (Aquic Eutrochrept) and Ishurdi (Aeric Haplaquept), and two soil series of non-calcareous origin, namely Tejgaon (Rhodic Paleustult) and Ghatail (Aeric Haplaquept), were selected. The soils were equilibrated with dilute solution of calcium chloride containing graded concentrations of phosphate (0, 1, 2, 5, 10, 25 and 50?μg?P?mL?1), and the amount of phosphate sorbed or desorbed was determined. Although all the soils showed potential for sorbing phosphate from applied phosphorus, their ability to sorb phosphorus differed. Increasing rates of phosphate application increased the amount of P sorption but reduced phosphate sorption percentage in all soils except Tejgaon. Phosphate was sorbed by the soils in the order: Tejgaon > Ghatail > Ishurdi > Gopalpur > Sara at 50?μg?P?mL?1 application. Soils possessing higher amounts of free iron oxide and clay sorbed more phosphate from applied phosphorus. 相似文献
18.
《Soil Science and Plant Nutrition》2013,59(6):726-733
Abstract The Japanese woody plant Chengiopanax sciadophylloides is well known for its extraordinary accumulation of manganese (Mn), and is used as a model for studying Mn uptake and utilization by plants. To clarify the role of manganese dioxide (MnO2) solubilization for Mn acquisition and further Mn hyperaccumulation in this plant, we examined the lowering of pH in the rhizosphere and Mn accumulation of this plant using regenerated plants. Plants regenerated from C. sciadophylloides calli lowered the pH of the culture broth continuously and simultaneously solubilized MnO2 added to the medium. The Mn content of the plant increased up to 1,300 mg kg?1 within 4 weeks of culture. Release of protein or specific organic acid from the roots was not observed. The medium used for plant culture maintained MnO2 solubilization ability after removal of the plant; however, this ability was lost by adjustment to the same medium pH of pre-culture conditions. In addition, pH lowering and MnO2 solubilization were suppressed by adding 1 mmol L?1 of the plasma H+-ATPase inhibitor Na3VO4 to the medium, and completely inhibited when 5 mmol L?1 of Na3VO4 was added. These results suggested that H+ leaking from plasma H+-ATPase plays an important role in MnO2 solubilization in the rhizosphere of C. sciadophylloides and in Mn accumulation in this plant. 相似文献
19.
不同铵钾比对高铵下拟南芥地上部和根系生长的影响 总被引:1,自引:0,他引:1
钾在缓解植物铵毒害的过程中起着重要的作用。本文研究了高铵(30 mmol/L)条件下,不同铵钾比(7.5︰1和150︰1)对拟南芥(Col-0)主根、侧根以及地上部生长的影响。结果表明:30 mmol/L NH4+条件下,高铵钾比(150)处理显著加重了拟南芥铵毒害现象,地上部和根系生长所受的抑制作用更为明显并导致更严重的氧化胁迫。相比低铵钾比水平,在高铵处理下,高铵钾比使得拟南芥主根伸长量降低57.4%,侧根数量减少33.3%,而地上部鲜重减轻69.9%。DAB(3,3¢-二氨基联苯胺,3,3¢-diaminobenzidine)叶片染色结果表明,不加铵处理下,外源不同钾水平(0.2和4.0 mmol/L)对拟南芥叶片的氧化胁迫作用没有显著差异;而高铵处理下,相比低铵钾比处理,高铵钾比显著增加了叶片中过氧化氢的含量,加重了其氧化胁迫。伊文思蓝(Evans blue,EB)染色结果表明,不加铵处理下,外源不同钾水平对拟南芥地上部和根部的膜透性没有显著差异,而高铵处理下,高铵钾比显著增强了拟南芥地上部和根部的膜透性,表明其对细胞的伤害程度加重。可见,高铵抑制拟南芥根系和地上部生长,高铵钾比则会加重这种抑制,其原因除了高浓度钾能减少植物对铵的吸收外,可能与高铵钾比条件加剧了植物的氧化胁迫有关。因此,适宜的铵钾比在植物应对铵毒害的过程中发挥重要作用。 相似文献
20.
《Communications in Soil Science and Plant Analysis》2012,43(1-2):265-271
This trial was carried out to study the evolution of the nutrient parameters of the nutrient solution applied to tomato plants (Lycopersicum sculentum Mill. Forteza) cultivated in Mediterranean greenhouse conditions under different fertigation management models. The dynamic model is based on soil water content, which was measured by tensiometers, and on soil solutions obtained with suction cups (porous ceramic cup water samplers). The local traditional method consists of following technical recommendations, and the classical model requires the estimation of Crop Factor (Kc) and knowing the nutrient extraction. Nutrient solution and water applied are functions of the fertigation management criteria. The water used for fertigation was classified as C4-S3 according to the Riverside classification system. The cultivation period lasted from 15 August to 20 April. The nutrient parameters studied in nutrient and soil solution were pH, electrical conductivity (EC), nitrate (NO3 ?), phosphate (H2PO4 ?), potassium (K+), calcium (Ca2+), magnesium (Mg2+), sodium (Na+), and chloride (Cl?). The pH shows similar trends under the different treatments. Electrical conductivity is in the range of 2.8–4.5 dS m?1. Chloride, sodium, magnesium, and sulfate are exclusively modified by the salt concentration in the irrigation water, so it can be assumed that the three treatments vary equally. Nitrate, potassium, phosphate, and calcium are modified depending on each fertigation management method. Soil solution is modified by the nutrient solution applied. Dynamic management allows low nutrient concentration in the nutrient solution to be maintained and keeps soil nutrient concentration low, reducing fertilizer losses and therefore aquifer contamination. 相似文献