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1.
Soil microbial immobilization and plant uptake of N were evaluated for three forest types in Kochi, Shikoku district. During 196-d laboratory incubation, soil NO3 -N production in the Hinoki cypress forest was negligible for the initial 40 d and then rapidly increased, whereas NO3 -N production was rapid from the beginning in Japanese cedar and deciduous hardwood forests. Microbial immobilization of the labeled 15 N decreased in the order of NH4 -N>glycine-N>NO3 -N. The 15 N immobilization was higher for soil in the Hinoki cypress forest than other two soils. The delayed NO3 -N production in the Hinoki cypress forest was likely related with low availability of NH4 -N due to NH4 -N immobilization and substantial NO3 -N immobilization. In the field experiment, 15 N uptake by roots decreased in the order of NH4 -N>NO3 -N>glycine-N. The absorption of the labeled 13 C suggested direct uptake of organic N. The preference of N forms by root uptake was not different among forest types. Trees in three forest types can absorb inorganic and organic forms of N, suggesting trees absorb the N form that is the most abundant in the soil. 相似文献
2.
Fixation and transfer of nitrogen by white clover to ryegrass 总被引:4,自引:0,他引:4
Abstract. 15 N2 was used in a sealed controlled environment chamber to investigate the transfer of fixed nitrogen from white clover to perennial ryegrass growing in soil in pots. There was no difference in the 15 N content of roots and shoots of clover plants after exposure to 15 N. No labelled fixed nitrogen was detected in ryegrass plants growing with the clover plants for a period of 129 days. There was therefore no evidence of rapid direct transfer (excretion) of fixed nitrogen from clover to ryegrass. 相似文献
3.
Summary A clear understanding of the short-term decomposition and fate of crop residues is necessary to predict the availability of mineral N in soil. The fate of 13 C15 N-labelled wheat straw in a silty soil (Typic Hapludalf) was studied using particle size fractionation and in situ incubation in which the equivalent of 8 t dry matter per ha of straw was incorporated into the soil over 574 days. Soil samples were separated into five particle-size fractions by wet sieving after disruption of aggregates. The weight, C and N contents, and 13 C and 15 N atom excess of each fraction were determined. Straw-derived C disappeared rapidly from the > 2000-μm fraction with an estimated half-life of 53 'normalized' days (equivalent of 10°C and −0−01 MPA water potential). Straw-derived C appeared to be only temporarily stored in the intermediate fractions (1000–2000 and 200–1000 pm). The maximum net 13 C accumulation in the 50–200-μm fraction was 4·4% of added 13 C. Straw-derived C accumulated most rapidly and preferentially in the 50-μm fraction, which stabilized after 265 days and accounted for 70% of the residual 13 C on day 574. Although there was more residual 15 N than 13 C, the distributions and kinetics of the two isotopes in the fractions were similar. 相似文献
4.
While the benefits of earthworms to crop production are widely acknowledged, the mechanisms involved are poorly understood. We examined the effects of an anecic earthworm (Lumbricus terrestris) on the distribution of plant residue N in a corn (Zea mays)/soil system. Soil (mixed Ap and B horizons) mesocosms (10 cm diameter, 39 cm deep) were amended with 15N-labeled corn litter, inoculated with one earthworm per mesocosm (WORM) or none (CTRL), and pre-incubated for 1, 2 or 3 weeks. Earthworms and remaining plant residues were removed and sweet corn grown in the mesocosms in a greenhouse for 3 weeks. Litter, earthworms, shoots, roots and bulk and burrow soil were analyzed for total N and 15N. Plant and earthworm biomass were also determined. Earthworms had no significant effect on the N content of shoots, roots or bulk soil. Recovery of 15N ranged from 92.6 to 101.9% in CTRL and 60.2 to 83.2% in the WORM treatment. The 15N content of bulk soil in the WORM treatment was significantly higher than in CTRL and increased with pre-incubation time. Excess at.% 15N of burrow soil was 10–100 times higher than in bulk soil. Incorporation of 15N by shoots and roots was significantly higher in the WORM treatment and increased significantly with pre-incubation time only in the WORM treatment. In WORM mesocosms pre-incubated for 3 weeks, the distribution of added 15N was 9.8% in litter, 6.5% in plant, 31.5% in soil, 12.0% in earthworms and 39.8% presumably lost as gas; in CTRL mesocosms, the values were 75.7% in litter, 3.2% in plant, 13.7% in soil and 7.4% in presumed gas losses. The activities of L. terrestris altered the distribution of plant residue N significantly, increasing the transfer of N to plants and soil and enhancing losses of N in the gas phase as pre-incubation time increased. 相似文献
5.
6.
A. C. B. M. VAN DER KRUIJS M. T. F. WONG A. S. R. JUO A. WILD 《European Journal of Soil Science》1988,39(4):483-492
Labelled urea was applied to monolith lysimeters in the 1st year of a 2-year experiment at Onne in south-east Nigeria. On eight lysimeters maize and rice were grown in each of the 2 years. Four lysimeters were similarly cropped in the 2nd year after being uncropped in the 1st year. Measurements were made over the 2-year period of labelled and unlabelled mineral nitrogen in the drainage water, and labelled and unlabelled nitrogen in the crops. At the end of the experiment, weeds and the soil were also analysed for labelled and unlabelled nitrogen.
The total recovery of15 N in crop, soil and leachate varied between 70 and 93%. It was lowest when applied to the second season rice crop, which recovered only 15%, and highest when it was leached in the 1st year or was taken up by the maize crop. The highest crop uptake was 31%. The results indicate that, depending on the treatment, between 10 and 30% of the 15 N was immobilized in the soil, lysimeters cropped in the 1st year lost between 22 and 29% of the 15 N in drainage water, and between 7 and 30% was lost by denitrification. The accuracy of these figures is discussed. 相似文献
The total recovery of
7.
Amounts of the individual carbohydrate components derived from uniformly 14 Clabelled grass added to soil were monitored in incubations lasting for up to 2 years. Decomposition was enhanced by the presence of the earthworms. Allolobophora caliginosa and Lumbricus rubellus and the cranefly larvae Tipula paludosa. After 28 d larvae had increased the loss of 14 C-arabinose by 8.8% (compared to soil without larvae), -xylose by 15%, -non cellulose glucose by 5.3% and -cellulose glucose by 12.5%. Earthworms had increased the loss of 14 C-xylose by 5%, -galactose by 21% and -total glucose by 11% after 6 months, and by another 29%, 14% and 8% respectively after 12 months. The losses of 14 C, initially about 60% from soil with tipulid larvae after 1 month, and 50% from soil with earthworms after 3 months, became progressively less. Total 14 C losses in the presence of earthworms were 66% after 12 months and 60% after 2 years, respectively. Increased decomposition is considered to be the result of the mixing of soil and substrate by the invertebrates, rather than an effect of their digestive capabilities. 相似文献
8.
At Onne in South-east Nigeria, drainage water was collected from four monolith lysimeters and analysed for nitrate. The lysimeters contained an acid sandy loam. At the start of the first rainy season two lysimeters received urea labelled with 15 NO3 – and two received no nitrogen fertilizer; all four were uncropped in the first year.
The peak concentrations of15 NO3 – and of unlabelled (soil) NO3 – were found after 2.5 pore volumes of water had passed through the lysimeters. Using the same soil in the laboratory after fine sieving, the peak concentration of tritiated water was found at 1 pore volume whereas nitrate leaching was retarded. The pattern of nitrate leaching was well described by miscible and immiscible models which included an adsorption coefficient for nitrate. Over the 2 years 81.4% of the 15 N added at the start of the first rainy season was recovered in the drainage water. 相似文献
The peak concentrations of
9.
Suzette B. LINA Masanori OKAZAKI Dorothea Sonoko KIMURA Yoshiharu YANO Koyo YONEBAYASHI Masato IGURA Marcelo A. QUEVEDO Alan B. LORETO 《Soil Science and Plant Nutrition》2009,55(1):114-123
Previous trials have revealed variable responses of sago palm ( Metroxylon sagu Rottb.) to fertilizer application, particularly nitrogen (N). In the present study, we quantified the fertilizer use efficiency (FUE) of sago palm for the first time using 15 N-labeled fertilizer in pot and field experiments. The pot experiment was conducted in Japan using a 2:1 mixture of sand to Philippine soil. The field experiment was conducted in Leyte in the Philippines. Both experiments consisted of three replicates in each of three treatments: control, 15 N urea at 50 kg N ha−1 and 15 N urea at 100 kg N ha−1 . The N uptake of sago palm increased significantly, but inconsistently with increasing N application. The few instances of a significant increase in N uptake did not translate into significant improvements in growth parameters, except for the number of leaflets in the pot experiment. The FUE values for sago seedlings (< 6 months) in the pot experiment treated with 50 and 100 kg N ha−1 were 10.5 and 13.2%, respectively, whereas for the 2-year-old sago palms in the field, the corresponding FUE values were 14.8 and 12.0%. The FUE values were similar at the two levels of N application in both experiments. Sago growth parameters appeared to be insensitive to N application, suggesting that the form of N and the timing of N fertilization are important factors for sago palms. Therefore, the use of N fertilizer in sago production can only be justified after determining and fully understanding the response of sago palm to N application. 相似文献
10.
Abstract. In a laboratory study, 15 N ammonium fertilizer uptake and rice growth was determined in a non-acid sulphate marine soil (Typic Tropaquept) and an acid sulphate soil (Sulfic Tropaquept). Acid sulphate sensitive (IR 26) and acid sulphate tolerant (IR 46) rice varieties were grown in soil suspensions incubated at four Eh levels (+500, +250, +50, and -150 mV) in microcosms for three weeks. The results showed that rice grown in non-acid sulphate marine soils gave slightly better dry matter weight of 1.8g/pot, greater 15 N uptake of 12.8 mg N/pot, and higher total N uptake of 38.4 mg N/pot than under acid sulphate soil conditions indicating the non-acid marine soil is more favourable to rice culture. Growth as measured by weight of dry matter was significantly reduced from 2.1g/pot under oxidized condition (+500 mV) to 0.8g/pot under highly reduced condition (-150 mV). N uptake by rice was significantly reduced from 16.9 mg/pot at + 500 mV to 4.5 mg N/pot at -150 mV Total N uptake also decreased with decreasing Eh. Growth, 15 N uptake and total N uptake by acid sulphate tolerant rice, IR 46 were significantly higher than the acid sulphate sensitive rice variety, IR 26. Under highly reduced soil conditions (-150 mV), growing rice in acid sulphate soil would require additions of lime, intermittent irrigation and/or mid season drainage in order to increase soil redox potential and remove toxic substances. 相似文献
11.
Mizuhiko Nishida Mihoko Moriizumi Kazunari Tsuchiya 《Soil Science and Plant Nutrition》2005,51(4):577-581
The N recovery from 15 N-labeled swine manure compost and rice bran with or without simultaneous application of unlabeled cattle manure compost was examined in a paddy field with direct-seeded rice during a 1-year period (1 crop season). In all the 15 N-labeled materials including (15 NH4 )2 SO4 , the processes of N recovery from the 15 N materials by rice plants were different between the plots with and without application of cattle manure compost. At the tillering stage, the N recovery rates from the 15 N materials in the plots with application of cattle manure compost were significantly lower than those in the plots without application of cattle manure compost. These recovery rates, however, became close and no significant differences were observed at the maturity stage. Thus, simultaneous application of cattle manure compost could impede the N recovery from swine manure compost, rice bran as well as (NH4 )2 SO4 . 相似文献
12.
Satomi ISHII Nobuo SUZUI Sayuri ITO Noriko S. ISHIOKA Naoki KAWACHI Norikuni OHTAKE Takuji OHYAMA Shu FUJIMAKI 《Soil Science and Plant Nutrition》2009,55(5):660-666
Real-time images of nitrogen fixation in an intact nodule of hydroponically cultured soybean ( Glycine max [L] Merr.) were obtained. In the present study, we developed a rapid method to produce and purify 13 N-labeled radioactive nitrogen gas (half life: 9.97 min). 13 N was produced from a 16 O (p, α) 13 N nuclear reaction. The target chamber was filled with CO2 and irradiated for 10 min with protons at an energy of 18.3 MeV and an electric current of 5 μA, which was delivered from a cyclotron. All CO2 in the collected gas was absorbed and removed with powdered soda-lime in a syringe and replaced with helium gas. The resulting gas was injected into gas chromatography and separated and a 35 mL fraction, including the peak of [13 N]-nitrogen gas, was collected by monitoring the chromatogram. The obtained gas was mixed with 10 mL of O2 and 5 mL of N2 and used in the tracer experiment. The tracer gas was fed into the underground part of intact nodulated soybean plants and serial images of the distribution of 13 N were obtained non-invasively using a positron-emitting tracer imaging system (PETIS). The rates of nitrogen fixation of the six test plants were estimated to be 0.17 ± 0.10 μmol N2 h−1 from the PETIS image data. The decreasing rates of assimilated nitrogen were also estimated to be 0.012 ± 0.011 μmol N2 h−1 . In conclusion, we successfully observed nitrogen fixation in soybean plants with nodules non-invasively and quantitatively using [13 N]N2 and PETIS. 相似文献
13.
Gaseous N loss, through denitrification and NH3 − volatilization, was monitored throughout the growing season after spring application of 15 N labelled urea fertilizer to peaty gley soils supporting N-deficient Sitka spruce. From the 15 N data, it was calculated that only about 0.28% of applied N was lost through NH3 -volatilization, almost all within the first few days after fertilizer application. Approximately 0.05% of applied N was calculated to be lost through denitrification. Denitrification decreased slowly over a 4-month period after fertilizer application. Rates of NH3 -volatilization correlated with available NH4 + in the litter layer, while for the early part of the study when N-losses were highest, denitrification rates correlated with available NO3 − in the litter layer. Observations of gaseous N-loss are also discussed in relation to data from lysimetry, changes in soil pH, and the soil moisture regime. 相似文献
14.
PANG Jun-Zhu QIAO Yu-Hui SUN Zhen-Jun ZHANG Shuo-Xin LI Yun-Le ZHANG Rui-Qing 《土壤圈》2012,22(5):726-735
Earthworms,one of the most important macroinvertebrates in terrestrial ecosystems of temperate zones,exert important influences on soil functions.A laboratory microcosm study was conducted to evaluate the influence of the earthworm Eisenia fetida on wheat straw decomposition and nutrient cycling in an agricultural soil in a reclaimed salinity area of the North China Plain.Each microcosm was simulated by thoroughly mixing wheat straw into the soil and incubated for 120 d with earthworms added at 3 different densities as treatments:control with no earthworms,regular density(RD)with two earthworms,and increased density(ID)with six earthworms.The results showed that there was no depletion of carbon and nitrogen pools in the presence of the earthworms.Basal soil respiration rates and metabolic quotient increased with the increase in earthworm density during the initial and middle part of the incubation period.In contrast,concentrations of microbial biomass carbon and microbial biomass quotient decreased in the presence of earthworms.Earthworm activity stimulated the transfer of microbial biomass carbon to dissolved organic carbon and could lead to a smaller,but more metabolically active microbial biomass.Concentrations of inorganic nitrogen and NO3--N increased significantly with the increase in earthworm density at the end of the incubation(P<0.05),resulting in a large pool of inorganic nitrogen available for plant uptake.Cumulative net nitrogen mineralization rates were three times higher in the ID treatment than the RD treatment. 相似文献
15.
The amelioration of an acid Alfisol from a tea garden was studied by incorporating various plant materials: canola straw, wheat straw, rice straw, corn straw, soybean straw, peanut straw, faba bean straw, Chinese milk vetch shoot and pea straw prior to incubation for a maximum of 65 days. Soil pH increased after incubation with all the incorporated materials with the legumes causing the largest increases. The final soil pH was correlated with ash alkalinity ( r 2 = 0.73), base cations ( r 2 = 0.74) and N content ( r 2 = 0.93) of the applied materials. It was assumed that the incubation released the base cations in plant materials as they decomposed which ultimately increased the base cation saturation of the soil. Similarly, soil exchangeable Al was also decreased with the incorporation of the legume plant materials and corn straw and rice straw. Our investigation demonstrated that legumes are the preferred choice for controlling the soil acidity and also for reducing the toxicity of Al in acid soils. 相似文献
16.
S. BJARNASON 《European Journal of Soil Science》1988,39(3):393-406
In a laboratory experiment, soil was treated with 15 NH4 - and 15 NO3 -N compounds at various times during the incubation. Several approaches in the calculation of gross immobilization and gross mineralization between two sampling dates were compared and a new method was developed. It is based on a dynamic simulation model designed to interpret isotopic data and an optimization procedure used to determine the best fit between model output and experimental data. This flexible method was used to examine the validity of the assumptions usually made when calculating the gross transformations.
The results indicate that seriously erroneous estimates of the gross transformations can follow if it is assumed that remineralization of immobilized N does not occur. Less serious errors can result from the assumption that both opposing processes occur at a constant rate during the interval between sampling dates.
The combined use of the model and the optimization procedure has several advantages over traditional methods and some of the gross transformation estimates reported would not have been obtainable using older methods. 相似文献
The results indicate that seriously erroneous estimates of the gross transformations can follow if it is assumed that remineralization of immobilized N does not occur. Less serious errors can result from the assumption that both opposing processes occur at a constant rate during the interval between sampling dates.
The combined use of the model and the optimization procedure has several advantages over traditional methods and some of the gross transformation estimates reported would not have been obtainable using older methods. 相似文献
17.
Joseph Jawa Kendawang Sota Tanaka Kenji Shibata Nanae Yoshida John Sabang Ikuo Ninomiya Katsutoshi Sakurai 《Soil Science and Plant Nutrition》2005,51(4):515-523
The effects of burning on the levels of soil organic matter, soil nitrogen, and soil microbial biomass were studied by carrying out experimental shifting cultivation at two sites, Niah and Bakam in Sarawak, Malaysia. Vegetation biomass was burned in plots (10 × 10 m2 ) at the rates of 0 (control), 100, 200, and 300 Mg ha−1 at the Niah site and 0, 20, and 100 Mg ha−1 at the Bakam site. At the Niah site, the levels of total C and N of the soils did not change throughout the experiment in spite of enhanced soil respiration until 2 months after burning. Although burning induced an increase in the amount of NH4 -N of the soils, the readily available pool of N (the sum of the NH4 -N, NO3 -N, microbial biomass N, and extractable organic N pools) in the burned plots was depleted appreciably at the end of rice cultivation. The effects of burning on these properties tended to be substantial with increasing amounts of the vegetation biomass burned. On the other hand, the levels of total C and N and the readily available N pool at the Bakam site were low before burning compared with those at the Niah site, and the burning treatments did not affect them appreciably. While the rice yield at the Niah site reached the average value obtained in traditional shifting cultivation in Sarawak, that at the Bakam site was much lower. It was suggested that the flush of NH4 -N induced by burning was one of the major factors for rice growth. 相似文献
18.
为探讨周年不同施氮组合对冬小麦-夏大豆轮作体系土壤氮素及产量影响规律,于2017—2018年,在伊宁县农业科技示范园内开展大田试验,以冬小麦-夏大豆轮作为研究对象,在前茬麦季设置4个施氮水平:0(N0)、104(N1)、173(N2)、242 kg·hm-2(N3);后茬大豆设置3个施氮水平:0(S0)、69(S1)、138 kg·hm-2(S2),研究周年不同施氮组合对两季作物收获后农田0~100 cm土层土壤硝态氮(NO3--N)、铵态氮(NH4+-N)含量、无机氮残留量及产量的影响。结果表明,冬小麦不同施氮水平土壤NO3--N及NH4+-N含量均在20~40 cm土层达到最大值,且N3的土壤NO3--N和NH4+-N含量最高,分别达到14.65 mg·kg-1和4.26 mg·kg-1,土壤NO3--N含量平均分别较N0、N1、N2增加了92.86%、44.69%和17.03%,土壤NH4+-N平均依次增加了69.95%、26.10%和8.46%;而冬小麦施氮量越高,其土壤无机氮残留量越大,以麦季N3平均最高,为200.62 kg·hm-2。此外,前茬麦季施氮还能影响后茬大豆土壤中NO3--N、NH4+-N含量及无机氮残留量;夏大豆的土壤NO3--N和NH4+-N含量也在20~40 cm土层达到最大值,且N3S2的土壤NO3--N、NH4+-N含量及无机氮残留量最大,平均分别为18.61 mg·kg-1、 5.10 mg·kg-1、258.36 kg·hm-2。在麦季施氮173 kg·hm-2时(N2),冬小麦产量最高,平均为7 828.64 kg·hm-2,平均分别较N0、N1、N3增加35.45%、16.77%、6.26%;且在此基础上夏大豆当季再施氮69 kg·hm-2时(S1),夏大豆获得产量最高,平均为2 988.93 kg·hm-2,其周年总产量也达到最高平均,为10 817.5 kg·hm-2。综上所述,麦季施氮173 kg·hm-2,豆季施氮69 kg·hm-2既有利于提高麦豆周年产量,又能减少土壤氮素的残留量,可为当地一年两熟制高效施氮制度提供一定的参考标准。 相似文献
19.
盐碱草甸植被退化对土壤硝化作用强度的影响 总被引:1,自引:0,他引:1
为了解不同退化阶段盐碱草甸草原土壤硝化作用强度特征及其影响因素,采用空间代替时间的方法,以松嫩平原盐碱草甸草原植被退化过程中4种典型植物群落为对象,以未做处理为参照,设置刈割、施氮和刈割同时施氮3种处理,测定了土壤的硝化作用强度(NI)、pH值、电导率(EC)、含水量(SMC)和有效磷(OP)、硝态氮(NO-3-N)、铵态氮(NH+4-N)及全氮(TN)的含量。结果显示:(1)土壤NI与pH值、电导率、含水量、OP和NO-3-N呈极显著正相关关系(p<0.01);通过逐步回归分析的方法得出土壤NI的重要影响因子,重要影响因子对土壤NI影响强弱表现为:pH值>有效磷含量>含水量>硝态氮含量,并推断土壤硝态氮含量可作为土壤NI的一个重要表征参数。(2)未作处理时,星星草群落与碱蓬群落土壤硝化作用强度分别为13.4,13.5 mg/(kg·h),显著高于羊草群落和退化羊草群落的5.0,2.5 mg/(kg·h),刈割和施氮处理分别使星星草群落土壤NI提高96.88%,253.77%,混合处理使其提高413.70%,显著高于其他3种植物群落,由此可见,在人为刈割和施氮肥的干预下,星星草群落土壤铵态氮可能更易转变为硝态氮,氮素流失的风险也更大,因此可认为星星草群落处于盐碱草甸退化过程中的关键阶段。 相似文献
20.
三类土壤不同酰硝比供应下的辣椒产量、品质和氮素损失 总被引:1,自引:0,他引:1