首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 328 毫秒
1.
Yield responses of irrigated, field‐grown cotton to phosphorus fertilizer application in Australia have been variable. In an attempt to understand better this variability, the distribution of fertilizer P within soil P fractions was identified using 32P and 33P radioisotopes. The soil chosen, an alkaline, grey, cracking clay (Vertosol), was representative of those used for growing cotton in Australia. Chang and Jackson fractionation of soil P from samples collected within 1 h of application indicated that 49, 7 and 13% of the P fertilizer was present as 0.5 m NH4F, 0.1 m NaOH and 1 m H2SO4 extractable P, respectively. Over 89% of the P fertilizer was recovered as Colwell extractable P in these samples, suggesting that the majority of these reaction products was in a highly plant‐available form. Fertilizer‐P remained in an available form within the band 51 days after application, and 68% of the applied fertilizer‐P was recovered as Colwell‐P (1071 mg kg?1). The Colwell‐P concentration in the band was 35 times that in the unfertilized soil. Thus, the variability in crop response to P fertilizer application in these soils is not a consequence of fertilizer‐P becoming unavailable to plants. These results confirm the suitability of the Colwell (1963) sodium bicarbonate extraction method for measuring available P in these soils.  相似文献   

2.
Soil testing was conducted during 1985–2005 in 11 paddocks on sandy duplex soils on Newdegate Research Station, average annual rainfall of 377 mm, with about 70% falling in the May–October growing season, in the Mediterranean-type climate of southwestern Australia. The study was undertaken to determine lime and fertilizer requirements of eight crop species grown in rotation with one another (one crop each year in the typical May–October growing season, comprising wheat, Triticum aestivum L.; barley, Hordeum vulgare L.; oats, Avena sativa L.; lupin, Lupinus angustifolius L.; canola, Brassica napus L.; chickpea, Cicer arietinum L.; field pea, Pisum sativum L.; and subterranean clover-based pasture, Trifolium subterraneum L. All crops were sown using no-till. The study demonstrated that plant testing was required in conjunction with soil testing to confirm decisions based on soil testing and to assess management decisions for elements not covered by soil testing. Pasture dry-matter production seldom exceeds 2 t ha?1 during the growing season in the region, but clover pasture is valued as a break crop for diseases and pests of grain crops and to facilitate control of herbicide-resistant weeds for cropping. Pastures had negligible impact on soil-test values. By contrast, grain crops typically produce more dry matter than pasture (4–8 t ha?1) and consistently significantly resulted in soil pH, soil-test potassium (K), and organic carbon (C) of soil decreasing through time. Fertilizer phosphorus (P) was not applied to pasture but was applied while sowing most grain crops from 1985 to 1996, a common practice at the time, and soil-test P significantly increased through time in these years. Thereafter fertilizer P was only applied when soil-test P was less than the critical value for that soil and grain crop species resulting, in little P being applied in these years, and soil-test P significantly declined through time. Plant testing indicated P was adequate when soil testing indicated no fertilizer P was required. The soils only started to become K deficient in the mid-1990s because of the removal of indigenous soil K in grain, and fertilizer K was applied when soil-test K was less than the 50 mg kg?1 critical value determined for wheat and canola. Plant testing indicated K was adequate when soil testing indicated no fertilizer K was required, and it indicated K was adequate after fertilizer K was applied, showing K levels applied were adequate for grain production. Plant testing indicated nitrogen (N), sulfur (S), calcium (Ca), magnesium (Mg), copper (Cu), zinc (Zn), manganese (Mn), iron (Fe), and boron (B) were adequate for grain production. Electrical conductivity (EC) of soil was very variable but EC values indicated soil salinity was unlikely to reduce grain yields of all the crop species grown. We conclude soil testing for pH is reliable for indicating paddocks requiring lime to ameliorate soil acidity and to monitor progress of liming. Soil testing proved reliable for determining when fertilizer P and K needed to be applied. Research has shown that for the low rainfall cropping areas of southwestern Australia laboratories need to measure and report soil pH, soil-test P, and soil-test K every 1–3 years and the P-buffering index (estimating P sorption of soil), organic C, and electrical conductivity every 3–5 years.  相似文献   

3.
A calibrated soil test for phosphorus (P) fertilizer application to sugarcane (Saccharum spp.) grown on organic soils in southern Florida is an important best-management practice for minimizing P loads in water draining to the Everglades. The current calibration uses water as the soil extractant, which has the limitations of being very sensitive to pH and being most applicable to short-season crops. Phosphorus fertilizer rate studies at six locations (20 total crop years) were analyzed to develop an updated soil-test P calibration for sugarcane on organic soils. Phosphorus extracted with water, acetic acid, and Bray 2 did not consistently relate well to crop response. A new P soil-test calibration for sugarcane is proposed based on Mehlich 3 soil extraction, with a maximum rate of 36 kg P ha?1 with ≤ 10 g P m?3 in preplant soil samples and no P recommended with >30 g P m?3.  相似文献   

4.
The influence of the duration and conditions of storage of soil samples on the activity of soil enzymes (catalase, β-fructofuranosidase, and dehydrogenase) was studied for the main soils of southern Russia (different subtypes of chernozems, chestnut soils, brown forest soils, gray forest soils, solonetzes, and solonchaks). The following soil storage conditions were tested: (1) the air-dry state at room temperature, (2) the airdry state at a low positive (in a refrigerator, +4°C) temperature, (3) naturally moist samples at a low positive temperature, and (4) naturally moist samples at a negative (in a freezer, −5°C) temperature. It was found that the sample storing caused significant changes in the enzymatic activities, which depended on the soil type, the land use, the type of enzyme, and the duration and conditions of the sample storage. In the course of the storage, the changes in the enzymatic activity had a nonlinear character. The maximum changes were observed in the initial period (up to 12 weeks). Then, a very gradual decrease in the activity of the studied enzymes was observed. Upon the long-term (>12 weeks) storage under the different conditions, the difference in the activities of the soil enzymes became less pronounced. The storage of soil samples in the air-dried state at room temperature can be recommended for mass investigations.  相似文献   

5.
Phosphate (P) was added to soil in solution. The soil was air-dried or freeze-dried and then incubated at a range of temperatures for periods of up to 110 d. The rate of the continuing reaction between the P and soil was measured using the null-point method, and by measuring the amount of desorption induced by filter paper impregnated with iron oxide (Pi test). The reaction between soil and P continued in both air-dried and freeze-dried soil, albeit more slowly than in moist soil. Freezing the soil, whether moist or dry, virtually stopped the reaction. These results are consistent with the hypothesis that the continuing reaction between P and soil involves a solid-state diffusive penetration of the soil particles by the sorbed P ions. They also indicate that the common practice of storing soil air-dry, even for short periods at low temperature, will not preserve the P status of the soil as at sampling. It was estimated that for a sample of soil which remained moist at 25°C for 100d after the addition of 335 μg P g−1 soil, before being sampled and stored air-dry at 4°C for 16 years, the measured Pi test value would be about 15 μg P g−1. This compares with 46 μg P g−1 which is the estimated Pi test value measured on the same day as sampling. When samples cannot be analysed for P status immediately following sampling, they should be stored at the lowest convenient temperature, preferably below 0°C.  相似文献   

6.
Canola (oil seed rape, Brassica napus L.) is now a major crop grown on the predominantly sandy soils in southwestern Australia and knowledge about the phosphorus (P) requirements of the crop in the region is limited. The results of 22 experiments done in the region are reported to determine the relationships between absolute seed (grain) yield response to applied P and (1) soil test P (Colwell sodium bicarbonate procedure) and (2) concentration of P measured in dried shoots at the rosette growth stage. Large grain yield responses to applied P occurred when Colwell soil test P values for the top 10 cm of soil were < 20 mg/kg soil and when concentrations of P in dried shoots were < 3.6 g/kg. The fertilizer P requirements for optimal economic return for canola grain production in the region varied from 10–35 kg P/ha. The 9 different canola cultivars used in the experiments from 1987–2005 had no major effect on the relationship between absolute grain yield response to applied P and soil test P. Application of fertilizer P mostly had no significant effects on either oil or protein concentrations in grain.  相似文献   

7.
Abstract

When soils are extracted with sodium bicarbonate to measure soil test phosphorus (P) by the standard Colwell procedure, the concentration of P in the extract solution is measured using the Murphy and Riley procedure. This measures P as orthophosphate (PO4) and most of the organic P extracted is not measured. The total (inorganic plus organic) P extracted can be measured by digesting an aliquot of the extract solution with perchloric acid to convert all the extracted P to PO4 before measuring the P concentration by the Murphy and Riley procedure. This is called total Colwell P. Data from one crop and two pasture field experiments in Western Australia are presented in which soil test P measured in 1991 and 1992 by the standard and total Colwell procedures were compared. Fertiliser P residues, including organic P, accumulate in the topsoil because, (i) the fertiliser is applied to the surface of pastures, and (ii) crops are being increasingly sown by minimum (conservation) tillage when P is concentrated in the top approximate 5 cm of the soil compared with about 10 cm when crops are sown conventionally. Consequently, to measure soil test P in the present study, soil samples were collected in February 1991 to either 5 or 10 cm depth. For the two Colwell procedures and both sampling depths, soil test P was related to: (i) the level of P applied in previous years and to (ii) plant yield measured later on that year (the soil test P calibration). Soil test P was larger for the total Colwell procedure and for soil samples collected to 5 cm depth. Total Colwell P as the dependent variable was closely correlated with standard Colwell P as the independent variable. The relationship between soil test P and the level of P applied, and the calibration relating yield to soil test P, were different for standard and total Colwell P. Neither method can be claimed to be significantly better than the other. It is concluded that use of the total Colwell procedure instead of the standard procedure is not warranted. Likewise, there was no evidence that collecting soil samples to 5 cm to measure soil test P provided better estimates of the current P status of soils than collecting soils to the standard 10 cm depth. There is therefore no need to change the sampling depth.  相似文献   

8.
Subterranean clover was grown in pots in which the only source of phosphate (P) was from bands of soil which had been incubated with P for a range of times, and at different temperatures, when either moist or air-dry. The effectiveness of these incubated soils in supplying P to plants decreased with time of incubation. Effectiveness decreased after air-dry incubation, though not as quickly as after moist incubation. These results indicate that air-dry storage of soil samples is to be avoided if the samples are to be assessed for their ability to supply P to growing plants. They also indicate that the cost-saving to Australian farmers, derived from applying phosphate prior to the start of the growing season, may be balanced or even outweighed by a loss in fertilizer effectiveness due to the reaction between P and the soil in the weeks prior to germination of seed.  相似文献   

9.
In a field study of irrigated chile (Capsicum annum L.) production in southeastern Arizona and southwestern New Mexico from 2008 through 2009, soil and tissue test samples were analyzed for a spectrum of plant nutrients at 16 different sites, including nitrogen (N), phosphorus (P), potassium (K), zinc (Zn), iron (Fe), and boron (B). The objectives were to evaluate soil and tissue nutrient testing procedures and to establish basic soil and plant tissue-testing guidelines and recommendations with respect to yield potentials. Soil samples were collected before planting. Plant tissue samples from plots at all sites were collected at the following four stages of growth: first bloom (FB), early bloom (EB), peak bloom (PB), and physiological maturity (PM). Fertilizer and nutrient inputs were monitored, managed, and recorded within current extension guidelines for irrigated chiles. Results for soil and tissue analyses were compared to yield results. The results provide estimates for baselines, which can be tested through subsequent calibration experiments to establish recommendations for critical soil- and tissue-test values. Absolute minimum soil-test nutrient values were identified as 10 parts per million (ppm) P, 110 ppm K, 0.3 ppm Zn, 2.0 ppm Fe, and 0.25 ppm B. Absolute minimum FB leaf tissue test values were 0.2% P, 4.5% K, 10 ppm Zn, 80 ppm Fe, and 30 ppm B. Complete data sets for leaf and petiole tissue-test values for all stages of growth were collected. These soil-test and plant nutrient values will be evaluated in subsequent experiments to better define fertilizer nutrient inputs and to gain better nutrient-management efficiencies in irrigated chile production systems.  相似文献   

10.
Continuous use of organic and inorganic fertilizers influences soil physical and chemical properties. Stored samples from the last 24 years of the Magruder Plots were analyzed to document changes in soil organic carbon (SOC), total nitrogen (TN) and soil pH. Since 1947, the same six treatments have been evaluated. Treatments included the use of cattle manure, inorganic nitrogen (N), phosphorus (P), potassium (K), and lime (L). Each year, a composite surface soil sample (0–15 cm) was taken in each plot, air-dried at ambient temperature, ground to pass a 2 mm sieve, and stored at room temperature, 25°C. Averaged over 24 years’ the manure plots resulted in the highest SOC and TN. Manure application maintained SOC at 0.92 and adequate soil pH (>6.0). The use of commercial fertilizers lowered soil pH over time but had higher yields compared to the manure plot.  相似文献   

11.
《Journal of plant nutrition》2013,36(7):1071-1084
Calibration of field crop response to nutrient availability is the bases for making a fertilizer recommendation from soil and tissue analyses. The purpose of this study was to evaluate and summarize results from a series of experiments on silicon (Si) fertilization of rice in the Everglades Agriculture Area. Twenty-eight rice field experiments were conducted from 1992 through 1996. The experiments consisted of 2 to 5 rates of calcium silicate applied to soils (Histosols) of varying Si soil-test values. Soil samples were taken before planting and analyzed for acetic acid (0.5 mol L?1) extractable Si. Straw samples were collected at harvest and analyzed for total Si. Grain yield was determined. The “critical” levels for Si in the soil (point below which response to Si fertilizer is expected) calculated by the Cate & Nelson procedure was 19 mg Si L?1 soil. The amount of silicon to correct Si deficiency in the soil and to obtain optimum rice yield was 1500, 1120 and 0 kg ha?1 for low (<6 mg L?1), medium (6 to 24 mg L?1), and high (>24 mg L?1) level of soil Si, respectively. Silicon in the straw was classified as high when Si concentration was >34 g kg?1, medium when in between 17 and 34, and low when <17 g kg?1 (3.4 and 1.7%, respectively).

  相似文献   

12.
A series of field experiments from 1990 to 1994 in Yingtan, Jiangxi Province, were conducted on an upland red soil derived from Quaternary red clay which had been reclaimed three years before the experiments, in order to study the fertility characteristics and fertilizer requirements of the newly reclaimed soil. The field experiments included that on nutrient characteristics and fertilizer effect, that on K-supplying potential and K-Mg relationship, that on fertilization rates of K and N, etc. The newly reclaimed upland soil was low in both N and P, and its responses to nitrogen and phosphate application were very significant. The K-supplying potential was also low, so the soil was highly responsive to K fertilizer. The effect of Ca and Mg fertilizers was not so great for the reason that certain amounts of Ca and Mg were incorporated into the soil through application of calcium magnesium phosphate during land leveling before the experiments. Among the four micronutrients, B, Mo, Zn and Cu, B had the greatest effect on the soil. The fertilizer requirements of the soil were in an order of P and N > K > lime and B > Mg > Mo, Zn and Cu. Eight crops tested had different fertilizer-requiring characteristics. Rapeseed was very sensitive to P and B fertilizers. Barely was especially sensitive to P and lime and it also responded to B, Mo, Zn and Cu. And sweet potato was especially sensitive to K.  相似文献   

13.
Phosphorus (P) in an high-pH soil may not be readily available to a crop, even though soil-testing procedures indicate high levels are present. A 2-year field study was conducted to determine corn yield responses to different rates of P fertilization as a function of soil-test P levels determined using the Mehlich-3 extractant. In 1 of the 2 years of this study, corn yields responded to P application across all soil P levels in a linear plateau fashion, indicating that P availability was limiting regardless of soil P levels. Where soil-test P was less than 40 mg kg?1, corn yields showed a quadratic response to rate of P applied both years, and when soil-test P was between 40 and 60 mg kg?1, corn yields showed a response only in the second year, when better growing conditions occurred. Soil-test P levels based on the Mehlich-3 extractant identified deficiencies in soil P availability to the crop, which could be corrected by P fertilization on a high-pH soil. Uptake efficiency of applied P was low, indicating that much of the P applied was not available to the crop.  相似文献   

14.
有机酸对红壤磷素吸附特性的影响   总被引：2，自引：0，他引：2  
以不同供磷水平的旱地红壤为材料,探讨了柠檬酸、酒石酸和草酸对红壤磷素吸附特性的影响。试验结果表明,经有机酸培育后的红壤磷的吸附曲线与Langmuir方程吻合性很好,相关系数可达0.949~0.999。有机酸可使磷的吸附曲线类型发生转变,柠檬酸可使土壤磷的吸附等温线由第Ⅱ类型转化为第Ⅲ类型,酒石酸可改变CK与NPK处理的吸附类型,而草酸没有影响。柠檬酸可使土壤的Xm降低30%~75.3%,以PM处理中的降低程度最大。酒石酸和草酸却在不同程度上使土壤的Xm增大,二者可使Xm分别增加0.8~2.3倍和0.1~0.3倍。三种有机酸均可减小平衡常数K值,提高土壤磷素的吸附饱和度,对磷素吸附特征值的影响程度大小顺序为:柠檬酸>酒石酸>草酸。在磷素利用率低的红壤中,增施有机肥或配施有机肥是提高土壤磷素生物有效性的最佳途径。  相似文献   

15.
Various soil test methods including Olsen, Colwell, Bray and Truog have been used to assess the levels of plant‐available P (PAP) in soils situated in the highlands of Papua New Guinea (PNG). Up until now, though, there has been no guarantee that these tests provide valid assessments of PAP in these somewhat atypical organic matter‐rich tropical soils. Furthermore, the critical soil‐P concentrations associated with the tests have been based on studies conducted elsewhere in sub‐tropical and temperate latitudes and as such may or may not be valid for soils or cropping situations in PNG. Soil (Colwell)‐P and leaf‐P data collected during a recent survey of sweet potato gardens in the highlands of PNG were therefore used to determine if useful relationships existed between these variables for different groups of soils, and if they do, to use these relationships to evaluate critical soil Colwell‐P concentrations corresponding to a known critical concentration of P in sweet potato index leaf tissue. Separate, highly significant linear relationships were obtained between leaf‐P and Colwell‐P for soils of volcanic and non‐volcanic origins. Based on these relationships, the critical Colwell‐P concentration for volcanic soils was found to be four times greater than that for non‐volcanic soils, presumably because much of the P extracted from the former soils with alkaline sodium bicarbonate had been chemically ‘fixed’ via sorption and precipitation reactions with sesquioxides and rendered unavailable to plants at ambient soil pH. These critical Colwell‐P concentrations if adopted as benchmark values for the soil groups in question should ensure that the results of future soil fertility surveys involving Colwell‐P assessments are correctly interpreted.  相似文献   

16.
Most fertilizer phosphorus (P) rate recommendations for the north-central United States are based on combination of a critical soil-test P value and a mass-balance calculation of fertilizer P required to maintain critical soil-test P. Accurate estimates of grain P removal are an essential component of P mass-balance calculation. Current north-central extension service guidelines recommend that estimates of corn and soybean grain P removal should be calculated using constant grain P concentrations. We reviewed research from the north-central region to determine the extent to which variation in grain P concentration accounts for differences in crop P removal and to determine whether predictions of grain P concentration can be improved through consideration of soil-test P, crop yield, and fertilizer P application. We found that soil-test P, grain yield, and fertilizer P are predictor variables that may significantly improve estimates of grain P concentration for corn and soybeans.  相似文献   

17.
Fertilizer and temperature effects on urea hydrolysis in undisturbed soil   总被引：11，自引：0，他引：11  
Summary Few published studies have examined the effects of a continuous fertilizer application on urea hydrolysis. In the present study we investigated the effects of 9 years of continuous application of urea and P fertilizers on urea hydrolysis in undisturbed soil samples as affected by temperature (5–45°C). Undisturbed soil samples of surface horizons (0–7 cm) were obtained with cutting rings (50 cm3) from different fertilizer-treatment plots and inserted in polyethylene bottles (with cutting rings). Each soil sample (in the cutting ring) was treated with 10 ml urea solution (0.5 mmol urea N g-1 soil) and then broght to 90% field capacity. The samples were left to equilibrate for 30 min at a temperature of 4°C, then placed in an incubator at 37°C for 6 h. The results indicated that 9 years of continuous application of urea but not P had a significant effect on urea hydrolysis in soil. There was a good correlation between temperature and urea hydrolysis in soil. Q 10 was between 1.97 and 2.08 in the temperature range 5–45°C.  相似文献   

18.
Ongoing global warming may result in colder soil and thawing cycles and will increase the frequency of soil freezing‐and‐thawing‐treated cycles (FTCs) during winter in the cool‐temperate and high‐latitude regions. The purpose of this study was to determine the effects of repeated freeze–thaw cycles on the solubility and adsorption of P in lab and field experiments on Pellustert, Argiustoll, Haplustept, Fluvaquent, and Calciorthid soils, the major soil groups in E Turkey. The results demonstrated that, depending on the soil type, the freeze–thaw cycle could increase the adsorption and desorption of P within a certain temperature range. Repeated freezing and thawing decreased equilibrium P concentration (EPC) and increased P adsorption. EPC and P adsorption were strongly correlated with the number of FTCs. The highest P adsorption and the lowest P desorption was found in Pellustert followed by Argiustoll, Calciorthid, Haplustept, Fluvaquent when refrozen at –10°C for 15 d, then thawed at +2.5°C for 18 h, and 9 times FTC. However, in the field study, the adsorption value was lower than the value obtained from the laboratory condition. It appears that increasing the frequency of freeze–thaw processes depending on increase in temperature that leads to decreased plant‐available soil P pools, thus requires more P fertilizer in soil solution to supply adequate P during the plant‐growth period.  相似文献   

19.
Abstract

Use of adequate rates of phosphorus (P) in crop production on high‐P‐fixing acid soils is essential because of high crop response to P fertilization and the high cost of P fertilizers. Information on lowland rice response to thermophosphate fertilization grown on Inceptisols is limited, and data are also lacking for soil‐test‐based P fertilization recommendations for this crop. The objective of this study was to evaluate response of lowland rice to added thermophosphate and to calibrate P soil testing for making P fertilizer recommendations. A field experiment was conducted for two consecutive years in central Brazil on a Haplaquept Inceptisol. The broadcast P rates used were 0, 131, 262, 393, 524, and 655 kg P ha?1, applied as thermophosphate Yoorin. Rice yield and yield components were significantly increased with the application of P fertilizer. Average maximum grain yield was obtained with the application of 509 kg P ha?1. Uptake of macro‐ and micronutrients had significant quadratic responses with increasing P rates. Application of thermophosphate significantly decreased soil acidity and created favorable macro‐ and micronutrient environment for lowland rice growth. Across 2 years, soil‐test levels of Mehlich 1–extractable P were categorized, based on relative grain yield, as very low (0–17 mg P kg?1 soil), low (17–32 mg P kg?1 soil), medium (32–45 mg P kg?1 soil), or high (>45 mg P kg?1 soil). Similarly, soil‐test levels of Bray 1–extractable P across 2 years were very low (0–17 mg P kg?1 soil), low (17–28 mg P kg?1 soil), medium (28–35 mg P kg?1 soil), or high (>35 mg P kg?1 soil). Soil P availability indices for Mehlich 1 extractant were slightly higher at higher P rates. However, both the extracting solutions had highly significant association with grain yield.  相似文献   

20.
Abstract

The importance of different soil phosphorus (P) compounds and their transformation influenced by several soil and other factors is well established. However, the dynamics of short‐term processes taking part in the long‐term changes of soil P including immobilization and mobilization is still not completely documented. Laboratory incubation experiments were carried out at 10°C and 40°C for studying the influence of incubation on the availability of residual and freshly applied P in samples of a long‐term fertilization field trial conducted on a brown forest soil (U.S. taxonomy: Orthic Eutrochrept; FAO taxonomy: Eutric Cambisol). Samples showing three levels of P resulting from 10 years of intensive P fertilization (referred as P0, P1 and P2, respectively), were collected 30 years after fertilization ceased. Available P contents of soil samples were determined using three approaches: in water (modified Murphy–Riley method), sodium bicarbonate (Olsen, pH=8.5), and ammonium lactate (AL, pH=3.7) extract. Changes in the amounts of P were determined after 2 and 60 days of incubation in four freshly applied new treatments with increasing additions of P: 0, 100, 500, and 1000 mg of P2O5 per kg of soil, representing agronomic and extreme P rates. From the results of our experiments, it was suggested that after 2 days of incubation, at 10°C, both agronomic and extreme P rates resulted in significant increases in P content in each extract. On the other hand, after 60 days, even higher values were obtained. Decreases found in water‐P values after 60 days of incubation were considerable compared to either the Olsen‐P or the AL‐P values, indicating the decline of water‐soluble P forms and further evidence of immobilization with increasing incubation time and temperature. Correlation between water‐P, Olsen‐P, and AL‐P values were significant at both temperatures.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号