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1.
Dynamics of soil microbial biomass and nitrogen availability in a flooded rice soil amended with different C and N sources 总被引：4，自引：0，他引：4
A greenhouse experiment was conducted to compare effects of different C and N sources applied to a flooded soil on soil microbial
biomass (SMB) C and N, extractable soil organic N (NORG), and NH4
+-N in relation to plant N accumulation of rice (Oryza sativa L.). In addition to a control without inputs (CON), four treatments were imposed receiving: prilled urea (PU), rice straw
(RS), RS and PU (RS+PU), or Sesbania rostrata as green manure (SES). Treatments were arranged according to a completely randomized design with four replicates and further
consisted of pots with and without transplanted rice. While plant effects on the SMB were relatively small, the application
of organic N sources resulted in a rapid increase in SMB until 10 days after transplanting (DAT) followed by a gradual decline
until 73 DAT. Plant N accumulation data in these treatments clearly indicated that the SMB underwent a transition from a sink
to a source of plant-available soil N during the period of crop growth. Seasonal variation of the SMB was small in treatments
without amendment of organic material (CON, PU) presumably due to a lack of available C as energy source. Extractable NORG was significantly affected by soil planting status and organic N source amendment, but represented only a small N pool with
little temporal variation despite an assumed rapid turnover. Among the three treatments receiving the same amount of N from
different sources, the recovery efficiency of applied N was 58% for PU and 28% for both RS+PU and SES treatments at 73 DAT.
The N uptake of rice, however, was not driven by N availability alone, as most evident in the RS+PU treatment. We assume that
root physiological functions were impeded after application of organic N sources.
Received: 1 June 1999 相似文献
2.
K. H. Dickmann J. C. G. Ottow K. H. Diekmann S. K. De Datta 《Biology and Fertility of Soils》1996,21(1-2):103-108
Organic-N fertilizers in the form of flood-tolerant, leguminous, stem-nodulating Sesbania rostrata and Aeschynomene afraspera may be useful alternatives to resource-poor rice farmers if applied as green manure. Therefore, the accumulation of N by these green manure species and their effect on the performance and yield of wetland rice (IR 64) was examined at four different sites in Luzon, Philippines. Soils deficient in N, P, and K were selected and compared with the fertile Maahas clay of the International Rice Research Institute (IRRI) at Los Baños. The green manure plants were grown under flooded conditions for 49 days in the wet season of 1987, chopped, and then ploughed in before transplanting rice seedlings. In a second experiment, the effect of S. rostrata green manure was studied under rainfed conditions. All green manure treatments were compared to an urea treatment (60 kg N ha–1) and an untreated control. Both legumes developed well, even on the marginally productive soils. S. rostrata accumulated up to 190 kg N ha–1 and A. afraspera even accumulated 196 kg N ha–1 in the shoots. In all treatments, green manure increased grain yield significantly (P=0.05) over the untreated control, by 1.3–1.7 Mg ha–1. The yields were comparable to those obtained with 60 kg N ha–1 of urea fertilizer. S. rostrata caused the highest grain yield, of 6.5 Mg ha–1 on the Maahas clay soil of IRRI. The apparent release of exchangeable NH
4
+
-N in the soils after green manuring and the rice grain yield response showed that both green manure species may provide sufficient available N throughout the development of IR 64 in the wet season. In the rainfed marginal soil site, green manure with S. rostrata produced even higher rice grain yields than urea. Green manure therefore seems particularly attractive for poor farmers on marginally productive soils, at least as a temporary strategy to improve yield and yield sustainability. 相似文献
3.
Influence of NPK on performance of the stem-nodulating legumes Sesbania rostrata and Aeschynomene afraspera in lowland rice The stem-nodulating tropical legumes S. rostrata and A. afraspera are promising green manure species for the low-input rice farming systems of lowland areas. Nutrient imbalances and soils low in available nutrients can considerably affect the use of biofertilizers. Use of mineral N, P, and K fertilizers in the growth of S. rostrata and A. afraspera as biofertilizers for lowland rice in the Philippines was evaluated. Applied P and K both stimulated growth, nodulation, and N2 fixation. N accumulation in PK fertilized S. rostrata was about 40% higher than in nonfertilized green manure. Mineral N application (urea) depressed nodulation and N2 fixation (ARA) in roots and resulted in an increased ARA in stem nodules. The legumes produced more N gains in the presence of small amounts of N. Use of S. rostrata and A. afraspera green manure increased in all cases significantly rice grain yield. Thus integration of mineral N, P, and K fertilizers in a green manurebased rice farming system can considerably improve biofertilizer production and increase rice grain yield. 相似文献
4.
Simple and rapid chemical indices of soil nitrogen (N)-supplying capacity are necessary for fertilizer recommendations. In
this study, pot experiment involving rice, anaerobic incubation, and chemical analysis were conducted for paddy soils collected
from nine locations in the Taihu Lake region of China. The paddy soils showed large variability in N-supplying capacity as
indicated by the total N uptake (TNU) by rice plants in a pot experiment, which ranged from 639.7 to 1,046.2 mg N pot−1 at maturity stage, representing 5.8% of the total soil N on average. Anaerobic incubation for 3, 14, 28, and 112 days all
resulted in a significant (P < 0.01) correlation between cumulative mineral NH4+-N and TNU, but generally better correlations were obtained with increasing incubation time. Soil organic C, total soil N,
microbial C, and ultraviolet absorbance of NaHCO3 extract at 205 and 260 nm revealed no clear relationship with TNU or cumulative mineral NH4+-N. Soil C/N ratio, acid KMnO4-NH4+-N, alkaline KMnO4-NH4+-N, phosphate–borate buffer extractable NH4+-N (PB-NH4+-N), phosphate–borate buffer hydrolyzable NH4+-N (PBHYDR-NH4+-N) and hot KCl extractable NH4+-N (HKCl−NH4+-N) were all significantly (P < 0.05) related to TNU and cumulative mineral NH4+-N of long-term incubation (>28 days). However, the best chemical index of soil N-supplying capacity was the soil C/N ratio,
which showed the highest correlation with TNU at maturity stage (R = −0.929, P < 0.001) and cumulative mineral NH4+-N (R = −0.971, P < 0.001). Acid KMnO4-NH4+-N plus native soil NH4+-N produced similar, but slightly worse predictions of soil N-supplying capacity than the soil C/N ratio. 相似文献
5.
6.
Pot experiments were carried out to evaluate the response of rice to Sesbania rostrata green manure N as compared to urea fertilizer N under flooded conditions. After growing S. rostrata for 21 days with a 15N-labelled N source, the labelled Sesbania was applied to wetland rice as a green manure and the uptake of 15N from this substrate was compared to that from labelled urea. Rice was cultivated twice in the same pots. The rice was grown
for a period of 49 days in each case, separated by a period of 21 days when the soil was allowed to dry. The 15N content of the soil and shoots and roots of rice was determined and 15N balances established. The total N content of the shoots and roots of rice was determined by a non-tracer method. The percentage
recovery of 15N from shoot material which was derived from urea N was more than twice that from S. rostrata. The recovery of 15N from the pots receiving both green manure and urea was low, and not significantly different from that recovered from the
green manure treatment. As much as 64.5–73.5% and 40.1–41% of the 15N remained in the soil which had received green manure or urea, respectively. The overall recoveries of 15N varied between 86.5% and 94.4%. At the second harvest, the oven-dry weight of shoots was significantly (P<0.05) higher in green-manure treated pots, but the total N content did not differ significantly. Labelled N remaining in
the soil after amendment with the green manure was much more available to the rice crop than that remaining after the addition
of urea-N. The total recovery of labelled N (shoots plus roots) amounted to 65.5% and 74%, respectively of the residual labelled
N in the two S. rostrata treatments (i.e. 19.55 mg 15N pot–1 and 39.10 mg 15N pot–1) and 23.2% and 23.2% of the residual labelled N in the two urea treatments (i.e. 19.55 mg 15N pot and 39.10 mg 15N pot–1), respectively.
Received: 8 December 1997 相似文献
7.
Gamini Seneviratne S. A. Kulasooriya W. L. Weerakoon Thomas Rosswall 《Biology and Fertility of Soils》1992,14(1):37-42
Summary We used 15N technology to investigate N2 fixation by Sesbania speciosa and Sesbania rostrata and its transfer to a lowland rice crop after incorporation of the Sesbania spp. into soil as green manure. During the first 50 days after establishment in November–December 1989, S. speciosa and S. rostrata produced 1126 and 923 kg dry matter ha-1 respectively. They gathered 31 and 23 kg N ha-1 respectively, of which 62%±5% and 55%±3% respectively, came from N2 fixation. Both these species produced a greater biomass during September–October 1989, with S. rostrata producing more than S. speciosa. These results reflected differential responses by the plants to different day lengths at different times of the year. Furthermore, the dry matter yield and %N of 15N-labelled S. speciosa were smaller than those of the unlabelled plants, possibly due to inhibition of N2 fixation in root nodules by the chemical N fertilizers added during labelling. These differences were not so pronounced in the stem-nodulated S. rostrata. The increased grain yield of rice fertilized with N in the form of chemical fertilizer or green manure was a result of an increased number of panicles per hill. The rice crop manured with S. speciosa produced a lower grain yield, with a lower grain weight than that manured with S. rostrata. This was due to a low uptake of soil N by rice manured with S. speciosa. Recovery of N from the green manure in rice straw with S. speciosa was significantly higher than from rice manured with S. rostrata, because of the higher applied N uptake by rice manured with the former. 相似文献
8.
Nitrification inhibition of soil and applied fertilizer N is desirable as the accumulation of nitrates in soils in excess
of plant needs leads to enhanced N losses and reduced fertilizer N-use efficiency. In a growth chamber experiment, we studied
the effects of two commercial nitrification inhibitors (NIs), 4-amino 1,2,4-triazole (ATC) and dicyandiamide (DCD), and a
commonly available and economical material, encapsulated calcium carbide (CaC2) (ECC) on the nitrification of soil and applied NH4
+-N in a semiarid subtropical Tolewal sandy loam soil under upland [60% water-filled pore space (WFPS)] and flooded conditions
(120% WFPS). Nitrification of the applied 100 mg NH4
+-N kg–1 soil under upland conditions was retarded most effectively (93%) by ECC for up to 10 days of incubation, whereas for longer
periods, ATC was more effective. After 20 days, only 16% of applied NH4
+-N was nitrified with ATC as compared to 37% with DCD and 98% with ECC. Under flooded soil conditions, nitrates resulting
from nitrification quickly disappeared due to denitrification, resulting in a tremendous loss of fertilizer N (up to 70% of
N applied without a NI). Based on four indicators of inhibitor effectiveness, namely, concentration of NH4
+-N and NO3
–-N, percent nitrification inhibition, ratio of NH4
+-N/NO3
–-N, and total mineral N, ECC showed the highest relative efficiency throughout the 20-day incubation under flooded soil conditions.
At the end of the 20-day incubation, 96%, 58% and 38% of applied NH4
+-N was still present in the soil where ECC, ATC and DCD were used, respectively. Consequently, nitrification inhibition of
applied fertilizer N in both arable crops and flooded rice systems could tremendously minimize N losses and help enhance fertilizer
N-use efficiency. These results suggest that for reducing the nitrification rate and resultant N losses in flooded soil systems
(e.g. rice lowlands), ECC is more effective than costly commercial NIs.
Received: 25 May 2000 相似文献
9.
Transformations of nitrogen-15-labelled urea in a flooded soil as affected by floodwater algae and green manure in a growth chamber 总被引：1，自引：0，他引：1
The effects of floodwater algae and green manure on transformations of 15N-urea were studied in columns of a sandy loam soil in a growth chamber. The columns were flooded and either kept in the light,
to allow algal growth, or in the dark (control) for 17 days before adding the labelled urea. Changes in urea-, NO3
–- and NH4
+-N levels and the pH of the floodwater were measured over the subsequent 41-day period, during which the control column remained
in the dark and those containing algae were maintained either in the dark to cause the death of the algae or in the light.
Volatilized NH3 was monitored, and on termination of the experiment the distribution of 15N between NO3
–, NH4
+ and organic forms was measured in the soil. Urea hydrolysis was most rapid in the presence of both living algae and green
manure, followed by dead algae, and was slowest in the control. The concentration of NH4
+-N in the floodwater was, however, reduced in the presence of algae due to assimilation and NH3 volatilization owing to the raised day-time pH in the floodwater. NH3 volatilization for the first 10 days was rather high in the columns kept in the light compared to those in the dark. Total
volatilization plus denitrification losses were greatest where dead algae were present, owing to the absence of live algae
which assimilated more than half of the applied N. Algal growth in floodwater increased the depth of the aerobic soil layer
present at the soil-water interface. Subsequently, under dark conditions, stimulated algal growth reduced the depth of the
aerobic layer causing less nitrification, which resulted in lower losses of N due to denitrification, i.e. 17% of the applied
urea-N as compared to 39% in the light treatments. Although the presence of green manure caused a marked increase in the rate
of hydrolysis, algal assimilation prevented excessive N losses via volatilization, indicating that the retention of higher
quantities of NH4
+-N may have increased fertilizer-N use efficiency.
Received: 22 January 1999 相似文献
10.
M. D. Serna J. Bañuls A. Quiñones E. Primo-Millo F. Legaz 《Biology and Fertility of Soils》2000,32(1):41-46
The objectives of this work were to evaluate the inhibitory action on nitrification of 3,4-dimethylpyrazole phosphate (DMPP)
added to ammonium sulphate nitrate [(NH4)2SO4 plus NH4NO3; ASN] in a Citrus-cultivated soil, and to study its effect on N uptake. In a greenhouse experiment, 2 g N as ASN either with or without 0.015 g
DMPP (1% DMPP relative to NH4
+-N) was applied 6 times at 20-day intervals to plants grown in 14-l pots filled with soil. Addition of DMPP to ASN resulted
in higher levels of NH4
+-N and lower levels of NO3
–-N in the soil during the whole experimental period. The NO3
–-N concentration in drainage water was lower in the ASN plus DMPP (ASN+DMPP)-treated pots. Also, DMPP supplementation resulted
in greater uptake of the fertilizer-N by citrus plants. In another experiment, 100 g N as ASN, either with or without 0.75 g
DMPP (1% DMPP relative to NH4
+-N) was applied to 6-year-old citrus plants grown individually outdoors in containers. Concentrations of NH4
+-N and NO3
–-N at different soil depths and N distribution in the soil profile after consecutive flood irrigations were monitored. In
the ASN-amended soil, nitrification was faster, whereas the addition of the inhibitor led to the maintenance of relatively
high levels of NH4
+-N and NO3
–-N in soil for longer than when ASN was added alone. At the end of the experiment (120 days) 68.5% and 53.1% of the applied
N was leached below 0.60 m in the ASN and ASN+DMPP treatments, respectively. Also, leaf N levels were higher in plants fertilized
with ASN+DMPP. Collectively, these results indicate that the DMPP nitrification inhibitor improved N fertilizer efficiency
and reduced NO3
– leaching losses by retaining the applied N in the ammoniacal form.
Received: 31 May 1999 相似文献
11.
Summary
Azolla spp. and Sesbania spp. can be used as green manure crops for wetland rice. A long-term experiment was started in 1985 to determine the effects of organic and urea fertilizers on wetland rice yields and soil fertility. Results of 10 rice croppings are reported. Azolla sp. was grown for 1 month and then incorporated before transplanting the rice and 3–4 weeks after transplanting the rice. Sesbania rostrata was grown for 7–9 weeks and incorporated only before transplanting the rice. Sesbania sp. grew more poorly before dry season rice than before wet season rice. Aeschynomene afraspera, which was used in one dry season rice trial, produced a larger biomass than the Sesbania sp. The quantity of N produced by the Azolla sp. ranged from 70 to 110 kg N ha-1. The Sesbania sp. produced 55–90 kg N ha-1 in 46–62 days. Rice grain yield increases in response to the green manure were 1.8–3.9 t ha-1, similar to or higher than that obtained in response to the application of 60 kg N ha-1 as urea. Grain production per unit weight of absorbed N was lower in the green manure treatments than in the urea treatment. Without N fertilizer, N uptake by rice decreased as the number of rice crops increased. For similar N recoveries, Sesbania sp. required a lower N concentration than the Azolla sp. did. Continuous application of the green manure increased the organic N content in soil on a dry weight basis, but not on a area basis, because the application of green manure decreased soil bulk density. Residual effects in the grain yield and N uptake of rice after nine rice crops were found with a continuous application of green manure but not urea. 相似文献
12.
We studied N mineralization of legume green manures under laboratory and field conditions, and the effects of field green-manuring on the microbiological properties of an acid Alfisol soil. No significant differences were found in the mineralization rates of Sesbania (Sesbania cannabina), sunnhemp (Crotalaria juncea), and cowpea (Vigna unguiculata) green manure. Mineralization was higher in field-capacity moist soil than water-saturated soil. The decomposition of sunnhemp under field wetland conditions, in the absence of a rice crop, was a rapid as it was under in vitro conditions. The decomposition released considerable amounts of mineral N and the level of NH
4
+
-N was significantly higher than NO
3
–
-N. Significant improvements were observed in the microbial biomass, dehydrogenase activity, and bacterial populations in the field soil green-manured for rice for 3 years, compared with fertilized soil. 相似文献
13.
Substituting chemical fertilizers with manure is an important method for efficient nutrient management in rice cropping systems of China.Labile nitrogen(N) is the most active component of the soil N pool and plays an essential role in soil fertility.However,the effects of manure substitution on soil labile N in rice cropping systems and their relationships with soil properties,fertilization practices,and climatic conditions remain unclear and should be systematically quantified.Here,we investiga... 相似文献
14.
The effects of four treatments upon the N content of rice crop and soil in 1m2 irrigated microplots were compared: (1) PK fertilization + Sesbania rostrata (inoculated stems) ploughed in as green manure when it was 52 days old. (2) PK fertilization + S. rostrata (non-inoculated stems) ploughed in as green manure. (3) PK fertilization + ammonium sulphate (60kg N ha?1). (4) PK fertilization alone (control).The application of chemical N fertilizer (treatment 3) increased the grain yield by 169 g m?2 (1.69t ha?1). whereas incorporating S. rostrata as green manure resulted in a grain yield increase of 372 g m?2 (3.72t ha?1). N2 fixed by S. rostrata was estimated to be at least 26.7 g m?2 (267kg N ha?1), one third being transferred to the crop and two thirds to the soil. 相似文献
15.
Combined application of synthetic nitrogen (N) fertilizers and organic materials can enhance soil quality, but little is known
about the distribution of fertilizer N among different soil fractions after crop harvest. A pot experiment using 15N tracer was employed to address this question with three treatments, i.e., labeled urea-only (15NU), labeled urea + rice straw (15NU-S) and labeled rice straw + urea (15NS-U) applied to a Ferallic Cambisol (1:1 type soil clay mineral) and a Calcaric Fluvisol (2:1 clay mineral). Soil microbial
biomass N, fixed ammonium (fixed NH4+), exchangeable ammonium and soil organic N fractions by hydrolysis (6 N HCl) and their isotope abundance were determined
after the rice harvest. Soil newly formed N in urea + straw (U-S) treatments (15NU-S, 15NS-U) was the sum of labeled urea-N in 15NU-S and labeled straw-N in 15NS-U. Compared with 15NU, U-S significantly (P < 0.05) increased the content and percentage of newly formed total soil N, acid insoluble N, amino acid N, and hydrolysable
unknown N in both soils. In U-S treatment, straw amendment significantly (P < 0.05) reduced the content and percentage of newly formed fixed-NH4+-N in Fluvisol as compared with 15NU treatments. Soil microbes contributed to the larger percentage of newly formed amino acid N (P < 0.01) in Cambisol as compared with Fluvisol. Fertilizer N in various soil fractions was therefore strongly affected by
clay mineral type and microbes after the combined application of organic materials and synthetic N fertilizer. 相似文献
16.
Influence of N and non-N salts on atmospheric methane oxidation by upland boreal forest and tundra soils 总被引：10，自引：0，他引：10
S. C. Whalen 《Biology and Fertility of Soils》2000,31(3-4):279-287
The short-term (24 h) and medium-term (30 day) influence of N salts (NH4Cl, NaNO3 and NaNO2) and a non-N salt (NaCl) on first-order rate constants, k (h–1) and thresholds (CTh) for atmospheric CH4 oxidation by homogenized composites of upland boreal forest and tundra soils was assessed at salt additions ranging to 20 μmol
g–1 dry weight (dw) soil. Additions of NH4Cl, NaNO3 and NaCl to 0.5 μmol g–1 dw soil did not significantly decrease k relative to watered controls in the short term. Higher concentrations significantly reduced k, with the degree of inhibition increasing with increasing dose. Similar doses of NH4Cl and NaCl gave comparable decreases in k relative to controls and both soils showed low native concentrations of NH4
+-N (≤1 μmol g–1dw soil), suggesting that the reduction in k was due primarily to a salt influence rather than competitive inhibition of CH4 oxidation by exogenous NH4
+-N or NH4
+-N released through cation exchange. The decrease in k was consistently less for NaNO3 than for NH4Cl and NaCl at similar doses, pointing to a strong inhibitory effect of the Cl– counter-anion. Thresholds for CH4 oxidation were less sensitive to salt addition than k for these three salts, as significant increases in CTh relative to controls were only observed at concentrations ≥1.0 μmol g–1 dw soil. Both soils were more sensitive to NaNO2 than to other salts in the short term, showing a significant decrease in k at an addition of 0.25 μmol NaNO2 g–1 dw soil that was clearly attributable to NO2
–. Soils showed no recovery from NaCl, NH4
+-N or NaNO3 addition with respect to atmospheric CH4 oxidation after 30 days. However, soils amended with NaNO2 to 1.0 μmol NaNO2 g–1 dw showed values of k that were not significantly different from controls. Recovery of CH4-oxidizing ability was due to complete oxidation of NO2
–-N to NO3
–-N. Analysis of soil concentrations of N salts necessary to inhibit atmospheric CH4 oxidation and regional rates of N deposition suggest that N deposition will not decrease the future sink strength of upland
high-latitude soils in the atmospheric CH4 budget.
Received: 30 April 1999 相似文献
17.
Soil microbial biomass and nitrogen supply in an irrigated lowland rice soil as affected by crop rotation and residue management 总被引：5，自引：0，他引：5
C. Witt Kenneth G. Cassman Johannes C. G. Ottow Ulrich Biker 《Biology and Fertility of Soils》1998,28(1):71-80
Processes that govern the soil nitrogen (N) supply in irrigated lowland rice systems are poorly understood. The objectives
of this paper were to investigate the effects of crop rotation and management on soil N dynamics, microbial biomass C (CBIO) and microbial biomass N (NBIO) in relation to rice N uptake and yield. A maize-rice (M-R) rotation was compared with a rice-rice (R-R) double-cropping
system over a 2-year period with four cropping seasons. In the M-R system, maize (Zea mays L.) was grown in aerated soil during the dry season (DS) followed by rice (Oryza sativa L.) grown in flooded soil during the wet season (WS). In the R-R system, rice was grown in flooded soil in both the DS and
WS. Three fertilizer N rates (0, 50 or 100 kg urea-N ha–1 in WS) were assigned to subplots within the cropping system main plots. Early versus late crop residue incorporation following
DS maize or rice were established as additional treatments in sub-subplots in the second year. In the R-R system, the time
of residue incorporation had a large effect on NO3
–-N accumulation during the fallow period and also on extractable NH4
+-N, rice N uptake and yield in the subsequent cropping period. In contrast, time of residue incorporation had little influence
on extractable N in both the fallow and rice-cropping periods of the M-R system, and no detectable effects on rice N uptake
or yield. In both cropping systems, CBIO and NBIO were not sensitive to residue incorporation despite differences of 2- to 3-fold increase in the amount of incorporated residue
C and N, and were relatively insensitive to N fertilizer application. Extractable organic N was consistently greater after
mid-tillering in M-R compared to the R-R system across N rate and residue incorporation treatments, and much of this organic
N was α-amino N. We conclude that N mineralization-immobilization dynamics in lowland rice systems are sensitive to soil aeration
as influenced by residue management in the fallow period and crop rotation, and that these factors have agronomically significant
effects on rice N uptake and yield. Microbial biomass measurements, however, were a poor indicator of these dynamics.
Received: 31 October 1997 相似文献
18.
施用包膜尿素对水稻生长和氮磷流失的影响 总被引：8，自引：3，他引：5
施用新型肥料是减少养分径流损失的重要途径。采用田间试验研究了施用包膜尿素对水稻生长和径流氮磷损失的影响,试验设置CK(习惯施肥)、PU1(减磷41%、减氮20%、施普通尿素)、PU2(PU1基础上减氮13%)、UR1(PU2基础上施包膜尿素)和UR2(UR1基础上减氮13%)5个处理。结果表明:PU1和UR1处理水稻氮磷含量与CK处理相近,PU1成熟期氮、磷总积累量比CK增加11.21,2.69kg/hm~2。PU1和UR1处理成熟期地上部生物量和籽粒产量高于CK处理,籽粒产量分别提高7.68%,5.77%。PU1、PU2、UR1和UR2处理径流总磷含量和累积流失量比CK处理低,减少13.18%~21.51%。施用包膜尿素(PU1、PU2)处理径流总氮、铵氮和硝氮含量低于施用普通尿素(CK、UR1、UR2)处理;稻田径流总氮、铵氮和硝氮累积流失量分别减少12.90%~26.91%,54.52%~49.38%和4.03%~15.95%,其中包膜尿素处理铵氮累积流失量显著(P0.05)小于普通尿素处理。施用包膜尿素和优化施肥能促进水稻对氮磷养分的吸收,提高水稻籽粒产量,显著减少稻田氮磷流失量,值得在水稻生产中推广应用。 相似文献
19.
有机肥无机肥配施对稻田氨挥发和水稻产量的影响 总被引：64，自引：17，他引：64
在南方红壤区双季稻田进行田间试验,研究等氮、磷、钾量条件下,有机无机肥配施对稻田氨挥发及水稻产量的影响。结果表明,有机无机肥配合施用能显著地降低稻田氨挥发,减少氮素损失,提高氮肥利用率。单施化肥(尿素),其氨挥发损失达37.8%,而单施有机肥和有机无机肥各半配合施用,氨挥发损失分别为0.7％-1.0％和7.2％-18.2％。田间氨挥发持续的时间,早稻约在施肥后20d,晚稻为9-10d。虽然有机无机肥各半配合施用的水稻产量与单施化肥的相近,均比对照提高约70％,但前者的氮损失少,其氮肥利用率为34.9％,高于化肥处理(33.2％)和有机肥处理(28.0%)。有机无机肥配合施用对提高水稻产量和降低氮肥环境负效应的综合效应最佳。 相似文献
20.
《Journal of plant nutrition》2012,35(2):285-296
AbstractModern rice cultivation relies on chemical nitrogen (N) fertilizer that ultimately degrades soil health and creates environmental pollution. The increasing concerns about environmental pollution, restoring soil health, and conservation of energy, public attention is now towards green manures as supplement for N fertilizer. Sesbania rostrata is a popular leguminous green manuring crop that fixes atmospheric N2, improves soil health, and rice productivity through incorporation of its biomass in to soil. About 40–60?days plants provide 5–6 tons dry biomass that can supplement 50–100% N requirement. In world, it is adapted as pre-rice or post-rice green manuring crop. Long-term use of S. rostrata improves soil health and increased rice yield by 9–11% over chemical fertilizer. Use of S. rostrata in large scale for rice production can reduce environmental pollution problems as it can cut down chemical N requirement and thus reduction dispersal of Nr to the environment. 相似文献