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1.
D. S. Mikkelsen 《Plant and Soil》1987,100(1-3):71-97
Summary The flooded soil-rice plant ecosystem is extremely complex and final N budgets are the products of many N transformations
modified by physical, chemical and biological agents, to a large extent controlled by O2 fluxes, but interacting with each other over time. Topics reviewed include mineralization-immobilization, nitrification-denitrification,
NH
4
+
fixation, NH3 volatilization, leaching and run-off lossess. Nitrogen budgets constructed for water sown rice using temperate climate data
clearly show that the major mechanisms by which fertilizer N is removed is crop absorption, nitrification-dentrification and
NH3 volatilization. Proper fertilizer management can reduce losses and desirably increase fertilizer use efficiency. Nitrogen
budgets have proven useful in describing gains and losses from the various N transformation processes, all of which are environment
and management dependent. 相似文献
2.
A. Islam 《Plant and Soil》1970,33(1-3):533-544
Summary The concentrations of water soluble and ammonium acetate extractable phosphorus in all the soils under investigation first
increased and then decreased with time of submergence under rice cropping. The increase in soluble phosphorus in the three
acid soils of Luisiana, Casiguran and Guadalupe was related to decrease in the concentration of iron, calcium and reductant
soluble phosphates, while in slightly acidic Maahas clay, the increase was associated with decrease in iron and aluminium
phosphates. But in the calcareous soil, the increase was due to decrease in the concentration of aluminium and reductant soluble
phosphates. The decrease was due to the re-formation of insoluble aluminium, iron and calcium phosphates in Luisiana and Guadalupe
clays, to the formation of aluminium and calcium phosphates in Maahas and to the formation of calcium phosphate only in Casiguran
fine sand. The application of phosphorus at the rate of 100 pounds per acre produced better tillering, more penicles and higher
straw and grain productions in Luisiana, Casiguran and Guadalupe only where the level of soluble phosphate was very low in
pots where no phosphorus was applied. This study, thus, indicated the necessity of phosphorus fertilization in low land rice
for soils which are low in phosphorus and high in active iron and aluminium. 相似文献
3.
K. A. Ayotade 《Plant and Soil》1977,46(2):381-389
Summary The sulphide-ion electrode was used to study the kinetics and reactions of free hydrogen sulphide in solution of flooded rice
soils. The observed sulphide potential obeyed the Nernst equation over a range of sulphide-ion concentration from 10-1 to 10-19
M.
Peak H2S concentrations were lowest in neutral soils high in iron and manganese; moderately high in soils low in iron or high in
organic matter; and highest in acid sulphate soil low in iron. Harmful concentrations of H2S may be present in acid sulphate and acid soils low in iron during the first few weeks after flooding. The concentrations
in acid sulphate soils can be drastically lowered by liming.
There was thermodynamic evidence for the presence of FeS and ZnS in the solutions of most soils. 相似文献
4.
A semi-empirical model of methane emission from flooded rice paddy soils 总被引:13,自引:0,他引:13
Reliable regional or global estimates of methane emissions from flooded rice paddy soils depend on an examination of methodologies by which the current high variability in the estimates might be reduced. One potential way to do this is the development of predictive models. With an understanding of the processes of methane production, oxidation and emission, a semi-empirical model, focused on the contributions of rice plants to the processes and also the influence of environmental factors, was developed to predict methane emission from flooded rice fields. A simplified version of the model was also derived to predict methane emission in a more practical manner. In this study, it was hypothesized that methanogenic substrates are primarily derived from rice plants and added organic matter. Rates of methane production in flooded rice soils are determined by the availability of methanogenic substrates and the influence of environmental factors. Rice growth and development control the fraction of methane emitted. The amount of methane transported from the soil to the atmosphere is determined by the rates of production and the emitted fraction. Model validation against observations from single rice growing seasons in Texas, USA demonstrated that the seasonal variation of methane emission is regulated by rice growth and development. A further validation of the model against measurements from irrigated rice paddy soils in various regions of the world, including Italy, China, Indonesia, Philippines and the United States, suggests that methane emission can be predicted from rice net productivity, cultivar character, soil texture and temperature, and organic matter amendments. 相似文献
5.
B. Ramakrishnan S. Kumaraswamy K. Mallick T.K. Adhya V.R. Rao N. Sethunathan 《World journal of microbiology & biotechnology》1998,14(5):743-749
In a laboratory incubation study, effect of various anions on net methane production in two rice soils (alluvial and acid sulphate) under flooded conditions was examined. Methane production was considerable in alluvial soil and almost negligible in acid sulphate soil, albeit with a higher density of viable methanogens, during 30-day incubation without salts. Sodium salts of hydroxide and phosphate further stimulated methane production in alluvial soil and marginally in acid sulphate soil. But, addition of sodium molybdate, a selective inhibitor of sulphate-reducing bacteria, increased the production of methane in acid sulphate soil. In contrast, nitrite, nitrate, sulphite and sulphate suppressed the production of methane in both soils. Acetate served as an excellent substrate for methanogenesis in alluvial soil, but not in acid sulphate soil. Succinate and citrate also stimulated methane production especially in alluvial soil, but after a longer lag. In acid sulphate soil, most of the added carbon in the form of sodium salts of carboxylic acids was converted to CO2 and not methane, which is consistent with their preferential use by the sulphate-reducing bacteria. In general, none of the amendments could increase production of methane in acid sulphate soil to the same level as in alluvial soil. 相似文献
6.
7.
Soil CO2 venting as one of the mechanisms for tolerance of Zn deficiency by rice in flooded soils
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Marie‐Cecile Affholder Dominik J. Weiss Matthias Wissuwa Sarah E. Johnson‐Beebout Guy J.D. Kirk 《Plant, cell & environment》2017,40(12):3018-3030
We sought to explain rice (Oryza sativa) genotype differences in tolerance of zinc (Zn) deficiency in flooded paddy soils and the counter‐intuitive observation, made in earlier field experiments, that Zn uptake per plant increases with increasing planting density. We grew tolerant and intolerant genotypes in a Zn‐deficient flooded soil at high and low planting densities and found (a) plant Zn concentrations and growth increased with planting density and more so in the tolerant genotype, whereas the concentrations of other nutrients decreased, indicating a specific effect on Zn uptake; (b) the effects of planting density and genotype on Zn uptake could only be explained if the plants induced changes in the soil to make Zn more soluble; and (c) the genotype and planting density effects were both associated with decreases in dissolved CO2 in the rhizosphere soil solution and resulting increases in pH. We suggest that the increases in pH caused solubilization of soil Zn by dissolution of alkali‐soluble, Zn‐complexing organic ligands from soil organic matter. We conclude that differences in venting of soil CO2 through root aerenchyma were responsible for the genotype and planting density effects. 相似文献
8.
Butachlor inhibits production and oxidation of methane in tropical rice soils under flooded condition 总被引:1,自引:0,他引:1
In laboratory incubation experiments, application of a commercial formulation of the herbicide butachlor (N-butoxymethyl-2-chloro-2',6'-diethyl acetanilide) to three tropical rice soils, widely differing in their physicochemical characteristics, under flooded condition inhibited methane (CH4) production. The inhibitory effect was concentration dependent and most remarkable in the alluvial soil. Thus, following application of butachlor at 5, 10, 50 and 100 microg g(-1) soil, respectively, cumulative CH4 production in the alluvial soil was inhibited by 15%, 31%, 91% and 98% over unamended control. Since CH4 production was less pronounced in the sandy loam and acid sulfate soil, the impact of amendment with butchalor, albeit inhibitory, was less extensive than the alluvial soil. Inhibition of CH4 production in butachlor-amended alluvial soil was related to the prevention in the drop in redox potential as well as low methanogenic bacterial population especially at high concentrations of butachlor. CH4 oxidation was also inhibited in butachlor-amended alluvial soil with the inhibitory effect being more prevalent under flooded condition. Inhibition in CH4 oxidation was related to a reduction in the population of soluble methane monooxygenase producing methanotrophs. Results demonstrate that butachlor, a commonly used herbicide in rice cultivation, even at very low concentrations can affect CH4 production and its oxidation, thereby influencing the biogeochemical cycle of CH4 in flooded rice soils. 相似文献
9.
10.
In an effort to provide an explanation for the reported variability in fertilizer N efficiency from deepplaced urea on flooded rice, a set of controlled experiments was conducted to evaluate the effect of water percolation on fertilizer loss and plant uptake from15N labeled urea supergranules. Three soils of different texture (silt loam-clay) were subjected to various percolation rates (0–20 mm/day) while planted to rice which was harvested after approximately 40 days.The results indicate that moderate to high percolation through silt loam soil will lead to significant fertilizer N losses and drastically decrease the fertilizer uptake by plants. The permeability of the clay soil was too low for any leaching to take place. It is therefore concluded that deep placement of urea supergranules not be recommended in soils where percolation rates may exceed 5 mm/day, particularly if the cation exchange capacity of the soil is low. This experiment points to the need of evaluating and reporting the percolation rates in soils where experiments with supergranular urea are conducted.Contribution from the Agro-Economic Division of the International Fertilizer Development Center (IFDC), Muscle Shoals, Alabama 35660. 相似文献
11.
12.
Three techniques for estimating nitrification rates in flooded soils were evaluated in short-term incubation experiments using three soils. The techniques were based on inhibition of either ammonium or nitrite oxidation and 13N isotope dilution. Of four inhibitors of ammonium oxidation evaluated, one (allylthiourea) was ineffective and two (2-ethynylpyridine or phenyl acetylene dissolved in ethanol) promoted immobilization of ammonium. Emulsified 2-ethynylpyridine and acetylene were equally effective inhibitors of ammonium oxidation and had little or no effect on gross rates of N mineralization and immobilization. Four inhibitors of nitrite oxidation were evaluated, but this approach was compromised by the nonspecificity of three of the compounds—potassium cyanide, 2-ethylamino-4-isopropylamino-6-methylthio-s-triazine (ametryne) and 3-(3,4-dichlorophenyl)-1-methylurea (DMU)—and by the partial effectiveness of another (potassium chlorate). Two methods based on isotope dilution gave similar estimates of nitrification rates. These rates were similar to those estimated by inhibition of ammonium oxidation in one soil but were lower in the other two soils. In the latter two soils, nitrification of labeled ammonium derived from dissimilatory nitrate reduction resulted in underestimation of nitrification rates by isotope dilution. 相似文献
13.
Phosphorus availability to maize as influenced by organic manures and fertilizer P associated phosphatase activity in soils 总被引:2,自引:0,他引:2
Laboratory incubation and green house studies were conducted to compare the P availability of organic manures and P uptake from organic manures by maize. Various organic manures viz. Poultry manure (PM), Farmyard manure (FYM), Green manure (GM) and Crop residue (CR) and graded levels of fertilizer P were applied in Samana sandy loam and Ladhowal silt loam soils and incubated for 7, 15, 30, 60 and 90 days. Samples were analyzed for P availability, P uptake and alkaline phosphatase activity. The overall, phosphatase activity, Paranitrophenyl phosphate (PNP h−1 g−1), in the Ladhowal silt loam soil was higher than in the Samana sandy loam soil. As the level of inorganic P increased, the release of PNP h−1 g−1 soil also increased. Among different organic manures, PM registered the highest enzyme activity followed by FYM, GM and CR. Compared to 7 days incubation a slightly higher increase in PNP was noticed in samples from 90 days incubation in both soils. The differential phosphatase activity in the organic manures was further reflected in dynamic P availability. The highest amount of Olsen extractable P was in PM-treated soil followed by FYM, GM and field pea crop residue. Organic manure addition along with inorganic P, irrespective of the source, increased the Olsen extractable P throughout the incubation period. Total P uptake by maize increased with the increasing level of inorganic P in both soils. The highest uptake was obtained in PM-treated soil and lowest in the CR-amended soil. We conclude that PM more readily supplies P to plants than other organic manure sources. 相似文献
14.
In a greenhouse study, with and without rice plants, of five flooded Philippine rice soils whose organic C (OC) content varied
from 0.5 to 3.6%, incorporation ofSesbania rostrata, Azolla microphylla and rice straw affected the kinetics of soil solution NH
4
+
−N, K+, Fe2+, Mn2+, Zn2+, and P. Sesbania and Azolla increased NH
4
+
−N concentration above the control treatment, whereas rice straw depressed it. In all soils Azolla released less NH
4
+
−N than Sesbania. The apparent net N release depended on the soil and ranged from 44–81% for Sesbania and 27–52% for Azolla.
These effects persisted throughout the growth of IR36. Soil solution and exchangeable NH
4
+
−N increased initially but levelled off between 30 to 80 days and between 20 to 40 days after flooding (DF), respectively.
With rice, soil solution NH
4
+
−N concentration, reached a peak at 15–40 DF and declined to very low levels (<4mg L−1). In the 3 soils of low OC content nitrogen derived from green manure ranged from 34–53% and the apparent revovery of added
green manure N varied from 29–67%. Almost all N released from both Azolla and Sesbania were recovered in the rice plant in
all soils except Concepcion with only 77%. The concentration of K+, Fe2+, Mn2+ and P in the soil solution were higher with rice straw than Sesbania and Azolla in all soils except Hanggan which showed
no change in Fe2+ and Mn2+ but increased K+ and P. In general, rice straw, Sesbania and Azolla decreased Zn2+ concentration in all soils. 相似文献
15.
I. J. Manguiat G. B. Mascariña J. K. Ladha R. J. Buresh J. Tallada 《Plant and Soil》1994,160(1):131-137
Field experiments were conducted under flooded soil conditions using Maahas clay amended with urea and rice straw-sesbania mixtures during the wet and dry seasons. Parallel laboratory incubation tests were done. The objectives were 1) to determine N mineralization patterns and establish the relationship between mineralization parameters and either N availability or grain yield, and 2) to correlate the results of organic N mineralization studies in the laboratory with data from field experiments. The N mineralization patterns of flooded soils in the laboratory followed a logistic function. In laboratory studies, mineralization potential was positively correlated with extractable soil NH4
+-N at the end of the incubation period (cumulative available N). Likewise, mineralization potential calculated from laboratory studies was positively correlated with N uptake and grain yield from field studies. Extractable (NH4
++NO3
–)-N in the field correlated positively with extractable NH4
+-N in the laboratory. The extractable NH4
+-N from laboratory incubations at 14 days after transplanting, panicle initiation, and maturity was also highly and positively correlated with grain yield from field experiments. 相似文献
16.
17.
Marcia DeLonge Karen L. Vandecar Paolo D’Odorico Deborah Lawrence 《Plant and Soil》2013,365(1-2):201-209
Background and Aims
Bioavailable phosphorus (P) represents a primary constraint on productivity in many ecosystems on highly-weathered soils. Soil moisture can be important to determining P bioavailability and net primary productivity in these systems. However, hydrologic controls on P availability remain poorly understood.Methods
We used “resins” (anion-exchange membranes) to quantify the response of labile P, an estimate of bioavailable P, to soil moisture conditions in two highly-weathered soils (rendzina, ultisol). The resins were either incubated in soil or shaken with a soil-water slurry.Results
Resin incubations in aerobic soil effectively quantified labile P in soils under changing moisture conditions, extracting significant amounts of labile P while avoiding the disturbance imposed by slurries. Wetting field-moist soils resulted in pulsed labile P, with lagged peaks occurring days after the largest moisture additions. Re-wetting air-dried soils enhanced labile P immediately, with the largest amounts observed at the highest moisture levels; labile P steadily declined following the moisture addition.Conclusions
Soil moisture levels and history strongly impacted labile P, indicating the importance of both variables when interpreting labile P measurements. These results also suggest that P availability is linked to both the amount and timing of rainfall, with implications for plant productivity in regions exposed to changing moisture regimes. 相似文献18.
Aluminium,boron and molybdenum availability and uptake by rice in acid sulfate soils 总被引:1,自引:0,他引:1
Although Al toxicity is believed to be a problem in acid sulfate soils cropped to rice (Oryza, sativa L.), little is known about the behavior of other trace metals such as B and Mo in these soils. The objectives of this study were to measure the availability of Al, B, and Mo in these soils, to determine what governs the availability of these metals and to investigate the relationships between metal availability and uptake by rice. Metal availability and uptake by rice were evaluated in 134 flooded acid sulfate soils in the Central Plains region of Thailand and in a growth chamber study using 50 of the same soils. Soil and plant metal analyses were conducted at the panicle differentiation stage of growth in both studies and in the soil prior to transplanting in the growth chamber study. Metal activities were determined with GEOCHEM. The mineral phases believed to be governing Al3+ activities were jurbanite under low pH conditions and amorphous Al(OH)3 at high pH. The Al chemistry is believed to be intimately linked to the redox-pH cycle, which is driven by the monsoonal climate. Mortality of rice associated with Al toxicity was observed under field and growth chamber conditions. Interference in P uptake and/or assimilation was believed to be the mechanism of Al toxicity. Activities of B(OH)
4
–
and B(OH)
3
0
were found to be highly correlated to pH and ionic strength, respectively, with the latter being the dominant B ion found in these soils. Activities of MoO
4
2–
were positively correlated to pH and appeared to be controlled by wulfenite. Leaf Mo contents were found to be positively correlated with MoO
4
2–
activity. 相似文献
19.
Summary Poor or lack of response of lowland rice to P fertilization is a well-known fact. Several studies were conducted in this direction however, our understanding regarding the underlying mechanism has been far from clear. A remarkable influence of rice plants on P transformation in submerged soil is identified in this experiment which may shed light on this problem. Accordingly, in presence of rice plants P was mobilized during the initial growing period followed by immobilization. The increased microbial activity in presence of physiologically active roots was responsible for P mobilization, while capacity of rice plants to reoxidize the rhizosphere, by secretion of oxygen from roots, during later growing period was responsible for P immobilization.The extent of P mobilization decreased while that of immobilization increased with increasing P levels in different soils. At a given P level the ratio of P mobilization to immobilization was higher in a soil where crop growth was better and P uptake was higher as compared to another soil where crop growth was poor with lower P uptake.Thus, lowland rice plants appear to possess an unique physiological mechanism, to regulate the contrasting changes in P availability in the rhizosphere depending on P requirement by the plants or P availability in soil, which in turn is responsible for the poor or lack of response to P fertilization.The experiment was conducted in a growth chamber. Two soils with widely varying properties were used. 相似文献
20.
不同生长期转Bt基因水稻秸杆还土对淹水土壤酶活性的影响 总被引:12,自引:0,他引:12
在实验室条件下通过秸杆还土试验比较了不同生长期转Bt基因克螟稻及其亲本稻秸杆对淹水土壤酶活性的影响。研究结果表明,与同一生长期的亲本稻秸杆相比,孕穗期和成熟期克螟稻秸杆对淹水土壤磷酸酶活性的影响较小;相反,对淹水土壤脱氢酶活性的影响非常显著,并且孕穗期秸杆与成熟期秸杆的添加对淹水土壤脱氢酶活性的影响趋势也存在较大差异。推测造成淹水土壤脱氢酶活性的显著性差异的主要原因可能是由于Bt插入基因表达的多效性所致。结果认为土壤脱氢酶活性可作为转Bt基因水稻生态安全风险性评价的潜在指标。 相似文献