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1.
Non-destructive acetylene reduction assays were successfully performed using small (1.21) incubation chambers and a 1 h incubation at 20°C. The concentration of C2H2 substrate used in the assays reached saturation at a partial pressure of 10 kPa for nodulated subterranean clover and barrel medic grown in a sandy loam. The optimum rates of C2H2 reduction associated with both species occurred within the range of 25–50% of the soil moisture content at field capacity (33 kPa). The ratio of moles N2 fixed to moles C2H2 reduced was calculated to be 1:2.9 for the subterranean clover—Rhizobium symbiosis and 1:3.3 for the barrel medic—Rhizobium symbiosis.  相似文献   

2.
Liming materials are widely applied to alleviate soil acidification and increase rice yield in acidic soils, but their effects on nitrogen (N) use efficiency are still unclear. Here, we conducted a field-, pot-, and micro-plot experiment to investigate how the application of slaked lime (i.e., Ca(OH)2) affects the fate of chemical fertilizer-N and straw-N in a double rice cropping system. In the field experiment, liming increased grain yield and N uptake by an average of 9.0% and 10.6%, respectively. In contrast, CaCl2 application did not affect rice yield and N uptake, suggesting that the effects of lime application were not related to the addition of Ca2+. Results from a 15N tracer experiment (i.e., 15N-labeled urea and straw) indicated that liming reduced N uptake from fertilizer (−5.7%), but increased N uptake from straw (+31.3%). Liming also reduced soil retention of both urea- and straw-N and increased their loss rates. Taken together, our results indicate that although liming increases rice yield and N uptake, it lowers the use efficiency of fertilizer N and facilitates N losses. In addition, our results emphasize the need for long-term studies on the impact of liming on soil N dynamics in paddy soils.  相似文献   

3.
It has been suggested that liming can improve soil structure and thereby decrease losses of particles and associated nutrients. In this study, two types of structure lime, slaked lime (Ca(OH)2) and a mixed product of calcium carbonate (CaCO3) and slaked lime (Ca(OH)2), were applied at three different rates in field trials on clayey soils (23%–40% clay). A combination of primary tillage and structure liming was also studied, in a split-plot trial on a clayey soil (25% clay). Aggregate (2–5?mm) stability, measured as reduction in turbidity (which is strongly correlated with losses of particulate phosphorus), was significantly increased with the highest application rates of both structure lime products. Aggregate size distribution was also improved with structure lime, creating a finer tilth in the seedbed. Yield response to structure lime was not consistent, with both negative and positive responses over the four-year study period. Positive yield responses can possibly be attributed to the finer tilth preventing evaporation in two dry growing seasons. Negative yield responses were probably an effect of impaired phosphorus availability associated with limited precipitation in May-July in 2011 and 2013. Two years after liming, soil pH levels were significantly elevated in plots with the highest application rate of structure lime, whereas no significant increases were found three years after liming. However, a lingering effect of liming was still detectable, as manganese concentration in barley grain was significantly lower in plots with the highest application rates of both structure lime products in the fourth study year. These results indicate that structure liming can be used as a measure to mitigate phosphorus losses from clayey soils, thereby preventing eutrophication of nearby waters. However, the yield response was varying and unpredictable and thus further investigations are needed to determine the circumstances in which field liming can act efficiently not only to prevent phosphorus losses, but also to ensure consistent yield increases.  相似文献   

4.
Abstract

Positive effects of liming on the nitrogen (N) contents of perennial ryegrass (Lolium perenne) shoots might be due in part to the effects of increased exogenous calcium (Ca) level on the rate of N uptake by plants. To test this hypothesis, perennial ryegrass was grown in soil culture treated with different rates of lime, gypsum, and ammonium nitrate (NH4NO3), in a factorial combination. The effects of these treatments on yield, N offtake, and shoot chemical composition were examined at two consecutive harvests. At both harvests, liming significantly increased plant yield and N offtake. There was no response to gypsum at cut 1; but at the second harvest, a negative interaction occurred between the two Ca treatments such that gypsum increased plant yield and N offtake in the absence of lime but not in its presence. The results suggest that liming affects N recovery by swards in at least two different ways, each associated with a different phase in the soil MIT (Mineralization Immobilization Turnover) cycle. During phases of net N mineralization, liming by raising soil pH stimulates biomass activity and increases the amount of organic N mineralized. In contrast, during phases of net N immobilization, liming by increasing Ca availability in the rhizosphere improves the ability of plants to absorb N, and thus helps them to compete more effectively with the biomass for mineral N.  相似文献   

5.
Crop response to fertilization and liming was investigated in field and pot trials on sandy loam Dystric Albeluvisols (pH 4.2–4.3). Treatments in the field trial were: 1, no fertilizer; 2, PK; 3, NK; 4, NP; 5, NPK; 6, lime; 7, lime+PK; 8, lime+NK; 9, lime+NP; 10, lime+NPK. In the pot trial, they were: 1, no fertilizer; 2, N; 3, P; 4, K; 5, NP; 6, NK; 7, PK; and 8, NPK applied to unlimed and limed soils. All treatments were in four replicates. Crops sensitive to soil acidity (winter wheat, fodder beet, spring barley and clover-timothy ley) and the less acid-sensitive winter rye, potatoes, oats and lupins and oats mixture were sown in the field trial. In the pot trial, the acid-sensitive spring barley and red clover, and the less acid-sensitive oats and lupin-oats served as the test crops. Combined application of fertilizers (NPK) increased yields of crops sensitive to soil acidity in plots receiving lime by 23%, and those of crops less sensitive to soil acidity by 18% in comparison to crops grown on unlimed soils. The results of pot experiments corroborated the field results. When N was applied alone, crop yields were always higher than those recorded for P or K treatments on both the unlimed and limed treatments. N application proved to be a prerequisite for high crop yields in the soils investigated. Thus, the efficiency of P and K fertilizers increased in the order NK<NP<NPK, with the effects being accentuated more in the limed than in the unlimed treatments. The results demonstrated the importance of multi-nutrient (NPK) fertilization in combination with liming for enhancement of high crop productivity in the unlimed soil investigated. N applied alone in combination with liming produced relatively good yields; hence, where resources are limited for the purchase of P and K fertilizers, applying N and lime can be a viable option in the short term.  相似文献   

6.
Abstract

A pot experiment was performed during the 1992 growing season on an acid, sandy topsoil taken from a Swedish liming experiment. A central composite experimental design was used in order to study the effects of supply of phosphorus (P) and micronutrients at different liming levels on yield of barley (Hordeum vulgare L. c.v. Golf), mineral content in plant, straw, and grain, and level of soil extractable nutrients. The results showed no increase of yield due to liming despite the fact that lime increased the yield significantly in the field experiment. The soil appeared initially to have a good balance between the nutrients included in the experimental design with the exception of P. An excessive supply of manganese (Mn) decreased the yield. The contents of calcium (Ca) and aluminum (Al) in the plant were hardly affected by the treatments, while the contents of P, Mn, copper (Cu), and zinc (Zn) more than doubled compared to no supply. The contents of P, Cu, and Zn were mainly influenced by the supply of the actual element, while the content of Mn was more closely related to the supply of lime. Soil pH(H20) and CaCl2‐extractable P, Mn, Cu, and Zn were highly related to the supplies of lime, P, Mn, Cu and Zn, respectively. Only a few interactions were observed.  相似文献   

7.
The aim was to determine if changes in C and N mineralization after acidification and liming could be explained by changes in the soil organism biomass. Intact soil cores from F/H layers in a Norway spruce (C:N=31) and a Scots pine (C:N=44) stand in central Sweden were treated in the laboratory for 55 days with deionized water (control), weak H2SO4 (successively applied as 72 mm of acid rain of pH 3.1), strong H2SO4 (applied as a single high dose of pH 1), and lime CaCO3. Strong acidification reduced C mineralization and increased net N mineralization in both soils. Weak acidification resulted in similar but less pronounced effects. Liming initially stimulated C mineralization rate, but the rates declined, indicating that an easily available C source was successively used up by the microorganisms. Liming also increased net N mineralization in the C:N=31 humus, but not significantly in the C:N--44 humus. Strong acidification generally affected the amounts of FDA-active fungal hyphae, nematodes and enchytraeids more than the other treatments did. The increases in net N mineralization after acidification and liming could only partly be explained by the decreases in biomass N in soil organisms. Mineralization of biomass N from killed soil organisms could at the most explain up to about 30% of the increase in net N mineralization after strong acidification. Most of the effects on N mineralization seemed to depend on the fact that acidification reduced and liming increased the availability of C and N to the microorganisms. Furthermore, acidification seemed to reduce the incorporation of N from dead organisms into the soil organic matter and, thereby, make the N compounds more readily available to microbial decomposition and mineralization.  相似文献   

8.
A temporary decline in tree growth has often been observed after liming in coniferous forests poor in N but seldom in forests rich in N. To test the hypothesis that the decline was caused by decreases in N supply, C and N mineralization were estimated in incubated soil: (1) after liming in the laboratory, and (2) after earlier liming in the field. Liming increased the C mineralization rate in needle litter, nor humus and 0 to 5 cm mineral soil for a period of 40 to 100 days at 15°C. After that period, liming had no effect on the CO2 evolution rate in materials poor in N (C:N ratios 30 to 62) but increased the CO2 evolution rate in materials rich in N (C:N ratios 24 to 28). When liming induced nitrification, the CO2 evolution rate was reduced. Liming resulted in lower net N mineralization rate in needle litter and mor humus. The reduction was more pronounced when NH4 + was the only inorganic form than when NO3 ? was the predominant form. The reason is probably that chemical fixation of NH3 and amino compounds increases with increasing pH. Because of the fixation, the incubation technique most likely underestimated the mineralized N available to the roots. Taking this underestimation into consideration, liming initially reduced the N release in the litter layer. In the other soil layers, liming increased the N release in soils rich in N and had only small effects in soils poor in N. For the total N supply to the roots in the litter, humus and 0 to 5 cm mineral soil layers, liming caused a slight reduction in soils poor in N and a slight increase in soils rich in N. Data on tree growth corresponded with these results.The hypotheses that tree growth depressions can be caused by reduced N supply after liming and that tree growth increases can be caused by increased N supply after liming thus seem reasonable.  相似文献   

9.
Li  Yuan  Cui  Song  Chang  Scott X.  Zhang  Qingping 《Journal of Soils and Sediments》2019,19(3):1393-1406
Purpose

The aim of this meta-analysis was to investigate the interactive effects of environmental and managerial factors on soil pH and crop yield related to liming across different cropping systems on a global scale.

Materials and methods

This study examined the effects of liming rate, lime application method, and liming material type on various soil chemical properties and crop yield based on data collected from 175 published studies worldwide since 1980.

Results and discussion

The most important variables that drive changes in soil pH and crop yield were liming rate and crop species, respectively. Soil conditions, such as initial soil organic matter and soil pH, were more important for increasing soil pH in field-based experiments, while lime material type and application method were more important for improving crop yield. To effectively neutralize soil acidity, the optimum liming duration, rate, and material type were?<?3 years, 3–6 Mg ha?1, and Ca (OH)2, respectively. Averaged across different crop species, the application of CaO, CaCO3, Ca (OH)2, and CaMg (CO3)2 increased yield by 13.2, 34.3, 29.2, and 66.5%, respectively.

Conclusions

This meta-analysis will help design liming management strategies to ameliorate soil acidity and thus improve crop yield in agroecosystems.

  相似文献   

10.
A temporary decline in tree growth has often been observed after liming in coniferous forests poor in N but seldom in forests rich in N. To test the hypothesis that the decline was caused by decreases in N supply, C and N mineralization were estimated in incubated soil: (1) after liming in the laboratory, and (2) after earlier liming in the field. Liming increased the C mineralization rate in needle litter, mor humus and 0 to 5 cm mineral soil for a period of 40 to 100 days at 15°C. After that period, liming had no effect on the CO2 evolution rate in materials poor in N (C:N ratios 30 to 62) but increased the CO2 evolution rate in materials rich in N (C:N ratios 24 to 28). When liming induced nitrification, the CO2 evolution rate was reduced. Liming resulted in lower net N mineralization rate in needle litter and mor humus. The reduction was more pronounced when NH 4 + was the only inorganic form than when NO 3 ? was the predominant form. The reason is probably that chemical fixation of NH3 and amino compounds increases with increasing pH. Because of the fixation, the incubation technique most likely underestimated the mineralized N available to the roots. Taking this underestimation into consideration, liming initially reduced the N release in the litter layer. In the other soil layers, liming increased the N release in soils rich in N and had only small effects in soils poor in N. For the total N supply to the roots in the litter, humus and 0 to 5 cm mineral soil layers, liming caused a slight reduction in soils poor in N and a slight increase in soils rich in N. Data on tree growth corresponded with these results. The hypotheses that tree growth depressions can be caused by reduced N supply after liming and that tree growth increases can be caused by increased N supply after liming thus seem reasonable.  相似文献   

11.
Abstract

Field studies were conducted for four to seven years on two soils, Tangi silt loam (Typic Fragiudalf, fine‐silty, mixed, thermic) and Dexter loam (Ultic Hapludalf, fine‐silty, mixed, thermic), to determine the effects of phosphorus (P) applications on growth and nitrogen (N) content of white clover (Trifolium repens L.) and subterranean clover (Trifolium subterranum L.) and on ammonium (NH4 +)‐ and nitrate (NO3 ‐)‐N, total N, and organic carbon (C) levels in the soils at the end of the study. Phosphorus applications consistently and significantly increased forage yields and led to significantly higher N yields by the clovers. Increases in plant yields and N2‐fixation, however, were not reflected in higher soil N and C levels. On Tangi soil, NH4 +‐ and NO3 ‐‐N levels were lowest where no P was applied but no statistically significant differences (P < 0.05) were found among P rates above 20 kg/ha. On the Dexter soils, no significant differences were found at any P application level. Significant differences due to higher clover yields at increasing P rates were not found in total N or organic C . levels in either soil. Greenhouse evaluations showed no differences in bermuda‐grass yield, N concentration, or total N recovery despite increasing subclover yields in the field during the previous seven years. Harvesting nearly all above ground clover growth caused plant roots to be the major N and C contributor to the soil. It is possible that root production was not increased in proportion to forage production as P applications increased. Perhaps increased microbial activities and some leaching losses also minimized accumulations of N and C released by clover roots.  相似文献   

12.
Glyphosale was added to samples of a sandy loam at rates of 0, 2, 5 and 10μg g?1soil. After 120 days, soil was transferred to pots which were planted with subterranean clover. Plants were inoculated with Rhizohium trifolii and N2 fixation (C2H2-reduction) was recorded after 9, 13, 15 and 19 weeks of growth. Nodule numbers and root weights were determined after the final C2H2-reduction assays had been performed. Decreased C2H2-reduction, nodule numbers and root weights associated with plants growing in glyphosate-treated soil indicated that this herbicide was not inactivated during the 120-days before planting.  相似文献   

13.

The main objective was to compare the response of grain yield to fertiliser N in a winter wheat-white clover intercropping system with the response in wheat alone. Clover was undersown in spring barley and remained established in two consecutive crops of wheat in two field experiments. Clover reduced grain yield in the first crop of wheat and increased it in the second. There was more inorganic N in the soil and a higher concentration of N in the grains in the intercropping system. The grain and N yield response to fertiliser N was equal or less with intercropped than with wheat alone. The reduction of clover biomass with a herbicide increased grain yield of the first crop of wheat without reducing the clover biomass or the positive residual effect in the second wheat crop. It was concluded that in order to produce large grain yields, competition from clover needs to be kept small when wheat is at the tillering stage.  相似文献   

14.
Abstract

Quantifying the effects of soil acidity on plant growth remains a challenging research topic as numerous soil and plant growth factors are influenced by pH and lime. In the field, annual ryegrass (Lolium multiflorum Lam. ‘Marshall') responded positively to the application of 3.8 Mg lime/ha on a strongly acid (pH 4.7) Lilbert loamy fine sand (loamy, siliceous, thermic, arenic Plinthic Paleudult) over three growing seasons. Dry matter yield in some cuttings, however, was better correlated with soil Al, P, Ca, Mg, and K than with pH. A greenhouse study was undertaken to quantitatively determine the effects of these five minerals plus Mo on ryegrass yield in limed and unlimed Lilbert soil material. Three ryegrass cuttings were obtained from unlimed (pH 4.8) or limed (1000 mg CaCO3/kg) Lilbert soil which was also amended with five rates of Ca, K, Mg, Al, P, and Mo in combinations stipulated by central composite design methodology. Response surface models that fit yield to the applied treatments and soil test data were complex because all factors and many interactions were significant. Furthermore, the models were transformed as the plants matured and element availability changed due to mineral uptake. Most yield improvement derived from liming occurred as a result of the elimination of exchangeable Al with a concomitant increase in P efficiency. Applied Ca did not alleviate Al toxicity in unlimed soil. Chlorotic plants developed in all pots where Mg was excluded. Yield was increased by applied Mg and Mo in unlimed soil, but not in limed soil. Applied K improved yield only in limed soil. Although regression accounted for a large portion of the yield variability (R2 values ranged from 0.75 to 0.95), these models were unable to accurately predict yield in control treatments.  相似文献   

15.
The application of nitrogen (N) fertilizers and liming (CaCO3) to improve soil quality and crop productivity are regarded as effective and important agricultural practices. However, they may increase greenhouse gas (GHG) emissions. There is limited information on the GHG emissions of tropical soils, specifically when liming is combined with N fertilization. We therefore conducted a full factorial laboratory incubation experiment to investigate how N fertilizer (0 kg N ha−1, 12.5 kg N ha−1 and 50 kg N ha−1) and liming (target pH = 6.5) affect GHG emissions and soil N availability. We focussed on three common acidic soils (two ferralsols and one vertisol) from Lake Victoria (Kenya). After 8 weeks, the most significant increase in cumulative carbon dioxide (CO2) and nitrous oxide (N2O) fluxes compared with the unfertilized control was found for the two ferralsols in the N + lime treatment, with five to six times higher CO2 fluxes than the control. The δ13C signature of soil-emitted CO2 revealed that for the ferralsols, liming (i.e. the addition of CaCO3) was the dominant source of CO2, followed by urea (N fertilization), whereas no significant effect of liming or of N fertilization on CO2 flux was found for the vertisol. In addition, the N2O fluxes were most significantly increased by the high N + lime treatment in the two ferralsols, with four times and 13 times greater N2O flux than that of the control. No treatment effects on N2O fluxes were observed for the vertisol. Liming in combination with N fertilization significantly increased the final nitrate content by 14.5%–39% compared with N fertilization alone in all treatment combinations and soils. We conclude that consideration should be given to the GHG budgets of agricultural ferralsols since liming is associated with high liming-induced CO2 and N2O emissions. Therefore, nature-based and sustainable sources should be explored as an alternative to liming in order to manage the pH and the associated fertility of acidic tropical soils.  相似文献   

16.
Abstract

The cost and difficulty of applying lime on hilly pastures or small forage fields makes it appropriate to devote attention to efficiency of lime utilization. This study evaluated effects of calcitic and dolomitic lime on yield and mineral composition of 11 forage species grown on soil with a low base status of 0.46 cmolc as Ca and 0.18 cmolc as Mg kg‐1. Both lime types increased dry matter production, but only Lolium multiflorum responded more positively to dolomitic lime. The low Mg level in the soil was not a major factor limiting yield. Increase in yield was mainly attributed to the increase in pH with the concurrent decrease in Al level and to an increased Ca availability to plants. The species ranked as follows according to the magnitude of yield increase due to calcitic liming: Trifolium fragiferum > Trifolium pratense > Vicia sativa > Vicia villosa > Trifolium repens > Lolium perenne > Lolium multiflorum > Festuca arundinaceae = Lolium (multiflorum x perenne x perenne) > Trifolium subterraneum > Dactylis glomerata. The most responsive, Trifolium fragiferum, did not grow without lime. The least responsive, Dactylis glomerata, showed a yield increase of 36%. A similar ranking was obtained when all species were evaluated for Al tolerance using a 48 hour root elongation bioassay. In both unlimed soil and soil limed with calcitic lime, Mg concentrations of all species were relatively low. Although they were generally not low enough to have an effect on yield, they barely met the Mg nutritional requirement of cattle. By adding dolomitic lime, Mg content increased in grasses an average of 3.7 fold and in legumes by 2.4 fold. Grasses were similar in Ca, Mg, and K concentrations within a soil treatment. Legumes showed a greater range with the two vetches having the lowest Ca and Mg concentrations and red clover the highest.  相似文献   

17.
Soil samples taken from 28 sites following varying periods of cropping in a crop-pasture rotation contained very low populations of Rhizobium trifolii. Populations were less than 103g?1R. trifolii of soil for 89% of the sites and were significantly correlated with soil pH. Application of lime resulted in a build-up of R. trifolii in the absence of the host legume, subterranean clover, but when inoculated clover seed was sown the populations built up to satisfactory levels after the first season's growth, regardless of soil pH.The number of nodules per plant was increased by the application of lime, but the plants growing in unlimed soil had fewer, larger nodules. The increase in nodulation with lime on these low-calcium acid soils persisted to the third growing season.  相似文献   

18.
施石灰石粉后红壤化学性质的变化   总被引：23，自引：0，他引：23       下载免费PDF全文
孟赐福  傅庆林 《土壤学报》1995,32(3):300-307
红壤施用石灰１０年的田间试验和盆栽试验的结果表明施用石灰能降低土壤酸度，增加土壤中效换性Ｃａ和Ｍｇ含量，从而导致作物产量的提高；底土酸度的降低随时间的推移和石灰用量的增大而增强，每倾施用３．２５－１５．０吨石灰石粉的降酸和增产效应至少可维持１０年以上。  相似文献   

19.
Calcium carbide (CaC2) is a rich source of the nitrification inhibitor acetylene (C2H2) and plant hormone ethylene (C2H4). C2H4 formed from biotic reduction of C2H2 released from CaC2 may accumulate in soil at physiologically active concentrations. Laboratory studies were conducted to evaluate the potential of encapsulated CaC2 for gradually releasing C2H2 and its product C2H4 in soil. The GC-FID analysis revealed that encapsulated CaC2 released a copious amount of C2H2 (up to 23700 nmol kg−1 soil), which was gradually reduced to C2H4 over a period of time via a strictly biotic reaction as no C2H4 was detected in CaC2-amended sterilized soil. Ammonium oxidation was suppressed by the encapsulated CaC2 indicating that C2H2 acted as a nitrification inhibitor. Results of pot trials conducted in the net house indicated that encapsulated CaC2 applied at 30 mg kg−1 soil significantly increased the number of tillers (up to 45.5%), root weight (up to 14.9%), straw (up to 32.8%) and grain yield (up to 37.3%) of wheat over the fertilizer application alone. In the case of cotton, the number of bolls, root, shoot and seed weight were also significantly increased in response to the application of encapsulated CaC2. Moreover, application of encapsulated CaC2 resulted in greater N-use efficiency (NUE) (up to 61.1%) by both wheat and cotton crops than that observed at the same rates of N fertilizer alone. These findings imply that CaC2 affects plant growth through hormonal action of C2H4 as well as improved NUE; however, the latter factor might be a relatively more contributing. It is desirable that CaC2 is formulated for gradually slow release of C2H2 and C2H4 in soil air.  相似文献   

20.
Abstract

A greenhouse study using lignite overburden surface soil from a lignite mine in northwest Louisiana was conducted to determine the yield response and nodulation of inoculated and non‐inoculated white clover (Trifolium repens L.) to P (0, 40, and 80 kg/ha) and Mo (0, 90, and 180 g/ha) fertilization. Results manifested a highly significant response of inoculated white clover to a single application of P and Mo. Application of P at the rate of 40 and 80 kg/ha increased the dry matter yield (DMY) of white clover by 164% and 154%, while Mo fertilization at the rate of 90 and 180 g/ha increased the dry matter yield (DMY) by 21% and 37%, respectively, over the control. The yield of white clover was also significantly affected by Rhizobium inoculation. Yield was increased from 2.1 to 2.5 Mg/ha which is equivalent to a 19% yield improvement over the non‐inoculated plants.

Nodule formation (NF), likewise, was significantly favored by P and Mo fertilization. Results also revealed that Rhizobium inoculation had remarkably improved the nodule count of white clover. Nodule count was increased from 0.4 to 5.5 or 1375% improvement between the inoculated and non‐inoculated plants. The non‐inoculated white clover also responded significantly to P fertilization, but not to Mo addition. Nodule formation, however, was not observed from the non‐inoculated white clover except at the highest rate of P and Mo additions. Increasing P supply significantly increased the concentrations of P, S, Na, and Ca but decreased the concentration of K in the clover. Mo additions resulted in increased concentrations of P and Ca. No significant P‐Mo interaction effects were observed on the nutrient concentration of white clover.  相似文献   

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