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1.
G. Amanuel R. F. Kühne D. G. Tanner P. L. G. Vlek 《Biology and Fertility of Soils》2000,32(5):353-359
N2 fixation by leguminous crops is a relatively low-cost alternative to N fertilizer for small-holder farmers in developing
countries. N2 fixation in faba bean (Vicia faba L.) as affected by P fertilization (0 and 20 kg P ha–1) and inoculation (uninoculated and inoculated) with Rhizobium leguminosarium biovar viciae (strain S-18) was studied using the 15N isotope dilution method in the southeastern Ethiopian highlands at three sites differing in soil conditions and length of
growing period. Nodulation at the late flowering stage was significantly influenced by P and inoculation only at the location
exhibiting the lowest soil P and pH levels. The percentage of N derived from the atmosphere ranged from 66 to 74%, 58 to 74%
and 62 to 73% with a corresponding total amount of N2 fixed ranging from 169 to 210 kg N ha–1, 139 to 184 kg N ha–1 and 147 to 174 kg N ha–1 at Bekoji, Kulumsa and Asasa, respectively. The total N2 fixed was not significantly affected by P fertilizer or inoculation across all locations, and there was no interaction between
the factors. However, at all three locations, N2 fixation was highly positively correlated with the dry matter production and total N yield of faba bean. Soil N balances
after faba bean were positive (12–58 kg N ha–1) relative to the highly negative N balances (–9–44 kg N ha–1) following wheat (Triticum aestivum L.), highlighting the importance of rotation with faba bean in the cereal-based cropping systems of Ethiopia.
Received: 13 January 2000 相似文献
2.
C. Van Nieuwenhove R. Merckx Lieven Van Holm Karel Vlassak 《Biology and Fertility of Soils》2001,33(1):25-32
Azorhizobium caulinodans was directly inoculated onto rice plants in three short-term pot trials. Addition of increasing amounts of sucrose (23, 46,
92 kg ha–1) did not influence the N economy of the A. caulinodans-rice association during the early vegetative growth stage. A. caulinodans inoculation alone and in combination with the highest amount of sucrose had a significantly positive effect on the N balance,
with small but significant N gains in the system. Application of 60 kg urea-N ha–1 had a negative impact on the N economy of the inoculated treatments. N losses increased and the amount of atmospheric N2 fixed and incorporated decreased significantly as compared to the amounts under the 20 kg urea-N ha–1 regime. However, N losses were low – a maximum of 8% – at the early vegetative growth stage under the conditions of the experiments.
C limitation does not seem to be a limiting factor for the incorporation of fixed N2 in this bacteria-plant association. Biological N2 fixation caused by A. caulinodans inoculation was responsible for 14% of the plant N at the vegetative growth stage and under low N conditions.
Received: 30 January 2000 相似文献
3.
Effect of microbial nitrogen immobilization during the growth period on the availability of nitrogen fertilizer for winter cereals 总被引:1,自引:0,他引:1
Pot and field experiments were conducted to determine microbial immobilization of N fertilizer during growth periods of winter
wheat and winter barley. In a pot experiment with winter wheat, Ca(15NO3)2 was applied at tillering [Zadok's growth stage (GS) 25)], stem elongation (GS 31) and ear emergence (GS 49). Rates of 100 mg
N pot–1, 200 mg N pot–1 or 300 mg N pot–1 were applied at each N application date. At crop maturity, 15N-labelled fertilizer N immobilization was highest at the highest N rate (3×300 mg N pot–1). For each N-rate treatment about 50% of the total immobilized fertilizer N was immobilized from the first N dressing, and
30% and 20% of the total 15N immobilized was derived from the second and third applications, respectively. In field trials with winter wheat (three sites)
and winter barley (one site) N was applied at the same growth stages as for the pot trial. N was also applied to fallow plots,
but only at GS 25. N which was not recovered (neither in crops nor in soil mineral N pools) was considered to represent net
immobilized N. A clear effect of N rate (51–255 kg N ha–1) on net N immobilization was not found. The highest net N immobilization was found for the period between GS 25 (March) and
GS 31 (late April) which amounted to 54–97% of the total net N immobilized at harvest (July/August). At GS 31, non-recovered
N was found to be of similar magnitude for cropped and fallow plots, indicating that C from roots did not affect net N immobilization.
Microbial biomass N (Nmic) was determined for cropped plots at GS 31. Although Nmic tended to be higher in fertilized than in unfertilized plots, fertilizer-induced increases in Nmic and net N immobilization were poorly correlated. It can be concluded that microbial immobilization of fertilizer N is particularly
high after the first N application when crop growth and N uptake are low.
Received: 6 July 1999 相似文献
4.
Influence of different agricultural practices (type of crop, form of N-fertilizer) on soil nitrous oxide emissions 总被引:4,自引:0,他引:4
N2O emissions were periodically measured using the static chamber method over a 1-year period in a cultivated field subjected
to different agricultural practices including the type of N fertilizer (NH4NO3, (NH4)2SO4, CO(NH2)2 or KNO3 and the type of crop (rapeseed and winter wheat). N2O emissions exhibited the same seasonal pattern whatever the treatment, with emissions between 1.5 and 15 g N ha–1 day–1 during the autumn, 16–56 g N ha–1 day–1 in winter after a lengthy period of freezing, 0.5–70 g N ha–1 day–1 during the spring and lower emissions during the summer. The type of crop had little impact on the level of N2O emission. These emissions were a little higher under wheat during the autumn in relation to an higher soil NO3
– content, but the level of emissions was similar over a 7-month period (2163 and 2093 g N ha–1 for rape and wheat, respectively). The form of N fertilizer affected N2O emissions during the month following fertilizer application, with higher emissions in the case of NH4NO3 and (NH4)2SO4, and a different temporal pattern of emissions after CO(NH2)2 application. The proportion of applied N lost as N2O varied from 0.42% to 0.55% with the form of N applied, suggesting that controlling this agricultural factor would not be
an efficient way of limiting N2O emissions under certain climatic and pedological situations.
Received: 1 December 1997 相似文献
5.
Yadvinder-Singh R. K. Gupta H. S. Thind Bijay-Singh Varinderpal-Singh Gurpreet-Singh Jagmohan-Singh J. K. Ladha 《Biology and Fertility of Soils》2009,45(7):701-710
Poultry litter (PL) is an important nutrient source; however, no information is available regarding its value in supplying
N and P in rice–wheat (RW) production. A three-year field study was conducted at Ludhiana, Punjab, India on a loamy sand soil
to identify optimum combination of PL and N and P fertilizers for a sustainable RW production. The litter was applied to rice
at 5 Mg ha−1 as a single application and supplemented with different rates of N. The residual effect of PL and the direct effects of the
different combinations of N and P were studied in the following wheat. Nitrogen and P mineralization from PL was studied under
controlled conditions in the laboratory, and macronutrient input–output balances were estimated from field results. About
46% of the N from PL was released after 60 days of incubation. The release of P from the PL occurred mainly during the initial
20 days after incubation, accounting for 15–17% of the total P. Combining PL with fertilizer N (40 kg ha−1) increased rice yield and nutrient uptake similar to what was obtained with the application of recommended fertilizer N (120 kg
ha−1). In the following wheat, the residual effect of PL was equal to 30 kg N ha−1 and 13 kg P ha−1. After three annual cropping cycles and PL application, mean soil organic C increased by 17%, Olsen-P by 73%, and NH4OAc-extractable-K by 24%. Most treatments had positive P but negative K balances. About 11% of the net P balance was recovered
from the soil as Olsen-P. The study showed that optimum N and P fertilizer doses for an RW system receiving 5 Mg ha−1 of PL are 40 kg N ha−1 for rice and 90 kg N + 13 kg P ha−1 for the following wheat. Safe and effective management of PL should be based on P balance, particularly when regular applications
of PL are to be made in the RW system. 相似文献
6.
Soil mineral nitrogen dynamics under bare fallow and wheat in vertisols of semi-arid Mediterranean Morocco 总被引:1,自引:0,他引:1
The evoluion of NH4
+-N and NO3
–-N was monitored during three growing seasons, 1992–1993, 1993–1994, 1994–1995 in the soil profile (0–60 or 0–90 cm) under
bare fallow and wheat on a vertisol site of the Sais plateau, Morocco. The aim of this study was to relate the soil mineral
N dynamics to crop N uptake and soil N transformation processes. The efficacy of the current N fertilisation rate (100 kg
N ha–1) for wheat production in the region was evaluated. The high level of residual mineral N in the soil profile resulted from
a low N plant uptake relative to the soil N supply and N fertilisation, and masked the effect of N fertilisation on dry matter
accumulation. NH4
+-N was present in considerable amounts, suggesting a low nitrification rate under the given pedo-climatic conditions. An artefact
due to the sampling procedure was encountered shortly after the application of N fertiliser. Losses through leaching and denitrification
occurred after heavy rainfall, but were limited. At least part of the exchangeable NH4
+-N seemed to be barely taken up by the crop. NO3
–-N was therefore considered to be a better indicator of plant-available N than total mineral N for this type of soil. The
low N fertiliser use efficiencies demonstrated clearly that the current fertilisation rate (100 kg N ha–1) for wheat production in this region is unsustainable. The maximum N uptake ranged from 40 kg N ha–1 to 180 kg N ha–1. The estimation of the seasonal production potential is considered to be the main prerequisite for the determination of the
best rates and timing of N fertiliser application in this region.
Received: 9 December 1997 相似文献
7.
P. Houngnandan N. Sanginga P. Woomer B. Vanlauwe O. Van Cleemput 《Biology and Fertility of Soils》2000,30(5-6):558-565
Leguminous cover crops such as Mucuna pruriens (mucuna) have the potential to contribute to soil N and increase the yields of subsequent or associated cereal crops through
symbiotic N fixation. It has often been assumed that mucuna will freely nodulate, fix N2 and therefore contribute to soil N. However, results of recent work have indicated mucuna's failure to nodulate in some farmers'
fields in the derived savanna in Benin. One of the management practices that can help to improve mucuna establishment and
growth is the use of rhizobial inocula to ensure compatibility between the symbiotic partners. Experiments were conducted
in 1995 and 1996 on 15 farmers' fields located in three different villages (Eglimé, Zouzouvou and Tchi) in the derived savanna
in Benin. The aim was to determine the response of mucuna to inoculation and examine the factors affecting it when grown in
relay cropping with maize. The actual amount of N2 fixed by mucuna in the farmers' fields at 20 weeks after planting (WAP) averaged 60 kg N ha–1 (range: 41–76 kg N ha–1) representing 55% (range: 49–58%) of the plant total N. The result suggested that mucuna in these farmers' fields could not
meet its total N demand for growth and seed production only by N2 fixation. It was estimated that after grain removal mucuna led to a net N contribution ranging from –37 to 30 kg N ha–1. Shoot dry weight at 20 WAP varied between 1.5 and 8.7 t ha–1 and N accumulation ranged from 22 to 193 kg N ha–1. Inoculation increased shoot dry matter by an average of 28% above the uninoculated treatments, but the increase depended
on the field, location and year. For the combinations of inoculated treatments and farmers' fields, the response frequency
was higher in Eglimé and Tchi than in Zouzouvou. The response to inoculated treatments was dependent on the field and inversely
related to the numbers of rhizobia in the soil. Soil rhizobial populations ranged from 0 to >188 cells g–1 soil, and response to inoculation often occurred when numbers of indigenous rhizobia were <5 cells g–1 soil. In two farmers' fields at Zouzouvou where extractable P was below 10 μg g–1 soil, mucuna did not respond to rhizobial inoculation despite a higher population of rhizobia. Significant relationships
between mycorrhizal colonization, growth and nodulation of mucuna were observed, and inoculated plants with rhizobia had a
higher rate of colonization by arbuscular mycorrhizal fungi (%AMF) than uninoculated ones. Therefore, it was shown that mucuna
will establish and fix N2 effectively in those fields where farmer's management practices such as good crop rotation and rhizobial inoculation allow
a build up of AMF spores that might lead to a high degree of AMF infection and alleviate P deficiency.
Received: 14 June 1999 相似文献
8.
Rapid nitrate leaching losses due to current agricultural N management practices under the humid tropical environmental conditions
of the Pacific island of Guam may contaminate fresh and salt water resources. Potential environmental contamination of the
Northern Guam aquifer, which is overlain by shallow limestone-derived soils, is a major public concern because the aquifer
is the sole underground source of fresh water for the island. The objectives of this study were to examine the use of waste
office paper as a possible management alternative for reducing nitrate leaching due to N fertilizer applications in northern
Guam while also providing sufficient N for crop growth. In a laboratory study, increasing rates of waste paper application
reduced NO3
–-N leaching up to approximately 200 days after incorporation of N fertilizer and paper treatments. Subsequent mineralization
of immobilized N from paper applications was also observed, although cumulative NO3
–-N leaching at the highest rate of paper addition was lower than the control after 394 days of incubation. The effect of waste
paper on N availability and NO3
–-N leaching after application of N fertilizer at rates up to 500 kg N ha–1 was also evaluated in two field experiments planted with sweet corn (Zea mays var. rugosa Bonaf.) during consecutive dry and wet periods. Leaching losses of NO3
–-N were higher during the wet cropping season, leading to lower crop yields and crop N uptake. Combining paper with N fertilizer
reduced NO3
–-N leaching losses but also decreased crop ear yields up to N fertilizer application rates of 250 kg N ha–1 during the dry cropping season and up to rates of 100 kg N ha–1 during the wet period. Although combining waste paper with N fertilizer reduced NO3
–-N leaching losses, no improvements in fertilizer N recovery were observed during the field experiments. This lack of crop
response may be due to the importance of early season N availability for the short-season horticultural crops grown on Guam.
We suggest that the application of waste paper may be a useful management practice to reduce NO3
–-N leaching losses when high soil NO3
–-N levels remain after cropping due either to crop failure or to over-application of N fertilizer.
Received: 11 May 1999 相似文献
9.
A long-term field experiment was conducted for 8 years on a Vertisol in central India to assess quantitatively the direct and residual N effects of soybean inoculation with Bradyrhizobium and wheat inoculation with Azotobacter in a soybean–wheat rotation. After cultivation of soybean each year, its aerial residues were removed before growing wheat in the same plots using four N levels (120, 90, 60 and 30 kg ha?1) and Azotobacter inoculation. Inoculation of soybean increased grain yield by 10.1% (180 kg ha?1), but the increase in wheat yields with inoculation was only marginal (5.6%; 278 kg ha?1). There was always a positive balance of soil N after soybean harvest; an average of +28 kg N ha?1 yr?1 in control (nodulated by native rhizobia) plots compared with +41 kg N ha?1 yr?1 in Rhizobium-inoculated plots. Residual and direct effects of Rhizobium and Azotobacter inoculants caused a fertilizer N credit of 30 kg ha?1 in wheat. Application of fertilizers or microbial inoculation favoured the proliferation of rhizobia in crop rhizosphere due to better plant growth. Additional N uptake by inoculation was 14.9 kg N ha?1 by soybean and 20.9 kg N ha?1 by wheat crop, and a gain of +38.0 kg N ha?1 yr?1 to the 0–15 cm soil layer was measured after harvest of wheat. So, total N contribution to crops and soil due to the inoculants was 73.8 kg N ha?1 yr?1 after one soybean–wheat rotation. There was a total N benefit of 13.8 kg N ha?1 yr?1 to the soil due to regular long-term use of microbial inoculants in soybean–wheat rotation. 相似文献
10.
Roberta Gentile Mike Dodd Mark Lieffering Shona C. Brock Phil W. Theobald Paul C. D. Newton 《Biology and Fertility of Soils》2012,48(3):357-362
Altered soil nutrient cycling under future climate scenarios may affect pasture production and fertilizer management. We conducted
a controlled-environment study to test the hypothesis that long-term exposure of pasture to enriched carbon dioxide (CO2) would lower soil nutrient availability. Perennial ryegrass was grown for 9 weeks under ambient and enriched (ambient + 120 ppm)
CO2 concentrations in soil collected from an 11.5-year free air CO2 enrichment experiment in a grazed pasture in New Zealand. Nitrogen (N) and phosphorus (P) fertilizers were applied in a full
factorial design at rates of 0, 12.5, 25 or 50 kg N ha−1 and 0, 17.5 or 35 kg P ha−1. Compared to ambient CO2, under enriched CO2 without P fertilizer, total plant biomass did not respond to N fertilizer, and tissue N/P ratio was increased indicating
that P was co-limiting. This limitation was alleviated with the lowest rate of P fertilizer (17.5 kg P ha−1). Plant biomass in both CO2 treatments increased with increasing N fertilizer when sufficient P was available. Greater inputs of P fertilizer may be
required to prevent yield suppression under enriched CO2 and to stimulate any response to N. 相似文献
11.
Long-term winter cover cropping effects on corn (Zea mays L.) production and soil nitrogen availability 总被引:1,自引:0,他引:1
This study was conducted to determine effects of long-term winter cover cropping with hairy vetch, cereal rye and annual
ryegrass on soil N availability and corn productivity. From 1987 to 1995, with the exception of the first year of the study,
the cover crops were seeded each year in late September or early October after the corn harvest and incorporated into the
soil in late April or early May. Corn was seeded 10 days to 2 weeks after the cover crop residues had been incorporated, and
N fertilizer was applied as a side-dressing at rates of 0, 67, 134, or 201 kg N ha–1 each year. While the average annual total N input from the above-ground biomass of the cover crops was highest for hairy
vetch (72.4 kg N ha–1), the average annual total C input was highest for cereal rye (1043 kg C ha–1) compared with the other cover crops. Hairy vetch was the only cover crop that significantly increased pre-side-dressed NO3
–-N (Ni) corn biomass and N uptake at 0 N. At an N fertilizer rate of 134 kg N ha–1 or higher, the cover crops had a minimal effect on corn biomass. This indicated that even after 9 years of winter cover cropping,
the effect of the cover crops on corn growth resulted primarily from their influence on soil N availability. The amount of
available N estimated from the cover crops (Nac) was significantly correlated with relative corn biomass production (r
2=0.707, P<0.001). The total amount of available N, comprising Nac and N added from fertilizer (Nf), was strongly correlated (r
2=0.820, P<0.001)) with relative corn biomass production. The correlation was also high for the available N comprising Ni and Nf (r
2=0.775, P<0.001). Although cereal rye and annual ryegrass did not improve corn biomass production in the short term, they benefited
soil organic N accumulation and gradually improved corn biomass production compared with the control over the long term.
Received: 10 August 1999 相似文献
12.
Xinkai Zhu Wenshan Guo Jinfeng Ding Chunyan Li Chaonian Feng Yongxin Peng 《Journal of plant nutrition》2013,36(12):1747-1761
Nitrogen (N) is one of the most important impact factors on development and growth of wheat. In this study the effects of nitrogen use efficiency on quantity and quality of grains were studied by agronomic management of N fertilizers on spring wheat (Triticum aestivum L.) grown under field conditions for two years. The experiments were performed at 16 combinations of N application amount and time, including four levels of N at 0, 60, 120 and 180 kg N ha?1 that were used as pre-plant fertilizers, sub-treated with four levels of the same N amount used as top-dress fertilizers. As a result, with an increase in total N fertilizers, grain yield increased in a cubic equitation, but partial factor productivity (PFPN, kg grain yield per kg N applied) decreased exponentially. With total fertilizers, N content and accumulation in vegetative tissues and grains increased linearly, but N uptake efficiency (UtEN, kg nutrient taken up per kg N applied) decreased exponentially. When N was over-applied (>360 kg N ha?1 in this study), grain yield clearly declined, due to decrease in productivity from per unit N. The high N level (240~300 kg N ha?1), the reasonable distribution between pre-plant and top dress from the same amount N fertilizer not only increased grain yield but also enhanced N use efficiency. 相似文献
13.
M. A. T. Vargas Ieda C. Mendes Mariangela Hungria 《Biology and Fertility of Soils》2000,32(3):228-233
Most soils sown with field beans (Phaseolus vulgaris L.) contain indigenous rhizobia which might interfere with the establishment of inoculated strains. As a consequence, the
benefits of bean inoculation are usually questioned, and the use of N fertilizer is gradually becoming a common practice.
The present study had the objective of evaluating the effectiveness of inoculation and N fertilization in field soil with
(site 1) and without (site 2) a previous bean-cropping history. At site 1, which had a rhizobial population of 7×102 cells g–1 soil, inoculation had no effect on nodulation or yield, whereas at site 2 (<10 cells g–1 soil) inoculation increased nodulation, nodule occupancy by the inoculated strain and grain yield. N fertilizer decreased
nodulation at both sites, but increased grain yield at site 1 but not at site 2, indicating that the response to inoculation
and N fertilization depends on the cropping history. When bean was cultivated for the first time, indigenous populations of
rhizobia were low and high yields were accomplished solely with seed inoculation, with no further response to N fertilizer.
In contrast, previous cultivation of bean increases soil rhizobia, preventing nodule formation by inoculated strains, and
N fertilizer may be necessary for maximum yields. A significant interaction effect between N fertilizer and inoculation was
detected for serogroup distribution only at site 2, with N fertilizer decreasing nodule occupancy by the inoculated strain
and increasing the occurrence of indigenous strains. Consequently, although no benefits were obtained by the combination of
inoculation and N fertilizer, this practice may be feasible with the selection of appropriate N-tolerant strains from the
indigenous rhizobial population.
Received: 26 May 1999 相似文献
14.
Nitrogen fixation in faba bean (Vicia faba cv. Mesay) as affected by sulfur (S) fertilization (30 kg S ha–1) and inoculation under the semi‐arid conditions of Ethiopia was studied using the 15N‐isotope dilution method. The effect of faba bean–fixed nitrogen (N) on yield of the subsequent wheat crop (Triticum aestivum L.) was also assessed. Sulfur fertilization and inoculation significantly (p < 0.05) affected nodulation at late flowering stage for both 2004 and 2005 cropping seasons. The nodule number and nodule fresh weighs were increased by 53% and 95%, relative to the control. Similarly, both treatments (S fertilization and inoculants) significantly improved biomass and grain yield of faba bean on average by 2.2 and 1.2 Mg ha–1. This corresponds to 37% and 50% increases, respectively, relative to the control. Total N and S uptake of grains was significantly higher by 59.6 and 3.3 kg ha–1, which are 76% and 66% increases, respectively. Sulfur and inoculation enhanced the percentage of N derived from the atmosphere in the whole plant of faba bean from 51% to 73%. This corresponds to N2 fixation varying from 49 to 147 kg N ha–1. The percentage of N derived from fertilizer (%Ndff) and soil (%Ndfs) of faba bean varied from 4.3% to 2.8 %, and from 45.1% to 24.0%, corresponding to the average values of 5.1 and 47.9 kg N ha–1. Similarly, the %Ndff and %Ndfs of the reference crop, barley, varied from 8.5 % to 10.8% and from 91.5% to 89.2%, with average N yields of 9.2 and 84.3 kg N ha–1. Soil N balance after faba bean ranged from 13 to 52 kg N ha–1. Beneficial effects of faba bean on yield of a wheat crop grown after faba bean were highly significant, increasing the average grain and N yields of this crop by 1.11 Mg ha–1 and 30 kg ha–1, relative to the yield of wheat grown after the reference crop, barley. Thus, it can be concluded that faba bean can be grown as an alternative crop to fallow, benefiting farmers economically and increasing the soil fertility. 相似文献
15.
Joseph C. Fetter Rebecca N. Brown Josef H. Görres Chong Lee José A. Amador 《Water, air, and soil pollution》2012,223(4):1531-1541
Consumer demand for cleaned squid generates a substantial amount of waste that must be properly disposed of, creating an economic
burden on processors. A potential solution to this problem involves converting squid by-products into an organic fertilizer,
for which there is growing demand. Because fertilizer application to lawns can increase the risk of nutrient contamination
of groundwater, we quantified leaching of NO3–N and PO4–P from perennial ryegrass turf (Lolium perenne L.) amended with two types of fertilizer: squid-based (SQ) and synthetic (SY). Field plots were established on an Enfield
silt loam, and liquid (L) and granular (G) fertilizer formulations of squid and synthetic fertilizers were applied at 0, 48,
146, and 292 kg N ha−1 year−1. Levels of NO3–N and PO4–P in soil pore water from a depth of 60 cm were determined periodically during the growing season in 2008 and 2009. Pore
water NO3–N levels were not significantly different among fertilizer type or formulation within an application rate throughout the
course of the study. The concentration of NO3–N remained below the maximum contaminant level (MCL) of 10 mg L−1 until midSeptember 2009, when values above the MCL were observed for SQG at all application rates, and for SYL at the high
application rate. Annual mass losses of NO3–N were below the estimated inputs (10 kg N ha−1 year−1) from atmospheric deposition except for the SQG and SYL treatments applied at 292 kg N ha−1 year−1, which had losses of 13.2 and 14.9 kg N ha−1 year−1, respectively. Pore water PO4–P levels ranged from 0 to 1.5 mg P L−1 and were not significantly different among fertilizer type or formulation within an application rate. Our results indicate
that N and P losses from turf amended with squid-based fertilizer do not differ from those amended with synthetic fertilizers
or unfertilized turf. Although organic in nature, squid-based fertilizer does not appear to be more—or less—environmentally
benign than synthetic fertilizers. 相似文献
16.
施用辐照处理的污水污泥对作物产量和土壤氮的影响 总被引:1,自引:0,他引:1
A field experiment was conducted to study the feasibility of irradiated and non-irradiated sewage sludge as a fertilizer for the growth of wheat and rice. The irradiated and non-irradiated sewage sludge were applied at rates of 0 (CK), 75, 150, 225 and 300 kg N ha-1 for wheat, and 0 (CK), 112.5, 225, 337.5 and 450 kg N ha-1 for rice, respectively. (NH4)2SO4 at a rate of 150 kg N ha-1 for wheat, and 225 kg N ha-1 for rice were added to the control treatments. Additionally, 20 kg 15N ha-1 in the form of (NH4)2SO4 was added to each treatment for wheat to study the effect of sewage sludge on chemical nitrogen fertilizer recovery. The results showed that the irradiation of sewage sludge by gamma ray at a dosage of 5 kGy increased crop yield by 11%~27% as compared to the non-irradiated treatments. Irradiation stimulated mineralization of organic nitrogen in the sludge and improved seedling growth. It was found that addition of irradiated sludge could reduce the leaching loss of chemical nitrogen fertilizer. Both irradiated and non-irradiated sewage sludge could increase the content of soil total nitrogen. Based on the preliminary results, it was concluded that irradiated sewage sludge could partly substitute for chemical nitrogen fertilizer in crop production. 相似文献
17.
R. Roscoe C. A. Vasconcellos A. E. Furtini-Neto G. A. A. Guedes L. A. Fernandes 《Biology and Fertility of Soils》2000,32(1):52-59
We studied the relationship between urease activity (UA) and soil organic matter (SOM), microbial biomass N (Nbiom) content, and urea-N fertilizer assimilation by maize in a Dark Red Latosol (Typic Haplustox) cultivated for 9 years under
no-tillage (NT), tillage with a disc plough (DP), and tillage with a moldboard plough (MP). Two soil depths were sampled (0–7.5 cm
and 7.5–15 cm) at 4 different times during the crop cycle. Urea was applied at four different rates, ranging from 0 to 240 kg
N ha–1. The levels of fertilizer N did not affect the UA, SOM content, and Nbiom content. No significant difference between the treatments (NT, DP, and MP) was observed for SOM during the experiment, probably
because the major part of the SOM was in recalcitrant pools, since the area was previously cultivated (conventional tillage)
for 20 years. The Nbiom content explained 97% and 69% of the variation in UA in the upper and deeper soil layer, respectively. UA and biomass N were
significantly higher in the NT system compared to the DP and MP systems. The highest maize productivity and urea-N recovery
was also observed for the NT system. We observed that the increase in urea-N losses under NT, possibly as a consequence of
a higher UA, was compensated for by the increase in N immobilized in the biomass.
Received: 2 July 1999 相似文献
18.
Nitrous oxide emissions from a fallow and wheat field as affected by increased soil temperatures 总被引:8,自引:0,他引:8
T. Kamp H. Steindl R. E. Hantschel F. Beese J.-C. Munch 《Biology and Fertility of Soils》1998,27(3):307-314
In order to determine the effects of increased soil temperature resulting from global warming on microbiological reactions,
a 21-month field experiment was carried out in the Bavarian tertiary hills. The major objective was to focus on N2O releases as either a positive or negative feedback in response to global warming. The soils of a fallow field and a wheat
field were heated 3 °C above ambient temperature and N2O fluxes were measured weekly from June 1994 to March 1996. During the experimental period, measured temperature differences
between the control plots and the heated plots were 2.9±0.3 °C at a depth of 0.01 m and 1.0–1.8 °C at a depth of 1 m. Soil
moisture decreased with the elevated soil temperatures of the heated plots. The mean differences in soil moisture between
the treatments were 6.4% (fallow field) and 5.2%DW (wheat field dry weight, DW), respectively. Overall N2O releases during the experimental period from the fallow field were 4.8 kg N2O–N ha–1 in the control plot against 5.0 kg N2O–N ha–1 in the heated plot, and releases from the wheat field were 8.0 N2O–N ha–1 in the control plot and 7.6 N2O–N kg ha–1 in the heated plot. However, on a seasonal basis, cumulated N2O emissions differed between the plots. During the summer months (May–October), releases from the heated fallow plot were
3 times the rates from the control plot. In the winter months, N2O releases increased in both the fallow and wheat fields and were related to the number of freezing and thawing cycles.
Received: 1 December 1997 相似文献
19.
Crop residues and fertilizer nitrogen influence residue decomposition and nitrous oxide emission from a Vertisol 总被引:2,自引:0,他引:2
Wisal Muhammad Sarah M. Vaughan Ram C. Dalal Neal W. Menzies 《Biology and Fertility of Soils》2011,47(1):15-23
Crop residues with high C/N ratio immobilize N released during decomposition in soil, thus reducing N losses through leaching,
denitrification, and nitrous oxide (N2O) emission. A laboratory incubation experiment was conducted for 84 days under controlled conditions (24°C and moisture content
55% of water-holding capacity) to study the influence of sugarcane, maize, sorghum, cotton and lucerne residues, and mineral
N addition, on N mineralization–immobilization and N2O emission. Residues were added at the rate of 3 t C ha−1 to soil with, and without, 150 kg urea N ha−1. The addition of sugarcane, maize, and sorghum residues without N fertilizer resulted in a significant immobilization of
soil N. Amended soil had significantly (P < 0.05) lower NO3−–N, which reached minimum values of 2.8 mg N kg−1 for sugarcane (at day 28), 10.3 mg N kg−1 for maize (day 7), and 5.9 mg N kg−1 for sorghum (day 7), compared to 22.7 mg N kg−1 for the unamended soil (day 7). During 84 days of incubation, the total mineral N in the residues + N treatments were decreased
by 45 mg N kg−1 in sugarcane, 34 mg kg−1 in maize, 29 mg kg−1 in sorghum, and 16 mg kg−1 in cotton amended soil compared to soil + N fertilizer, although soil NO3−–N increased by 7 mg kg−1 in lucerne amended soil. The addition of residues also significantly increased amended soil microbial biomass C and N. Maximum
emissions of N2O from crop residue amended soils occurred in the first 4–5 days of incubation. Overall, after 84 days of incubation, the
cumulative N2O emission was 25% lower with cotton + N fertilizer, compared to soil + N fertilizer. The cumulative N2O emission was significantly and positively correlated with NO3−–N (r = 0.92, P < 0.01) and total mineral N (r = 0.93, P < 0.01) after 84 days of incubation, and had a weak but significant positive correlation with cumulative CO2 in the first 3 and 5 days of incubation (r = 0.59, P < 0.05). 相似文献
20.
Influence of nitrogen on cellulose and lignin mineralization in blackwater and redwater forested wetland soils 总被引:2,自引:0,他引:2
J. A. Entry 《Biology and Fertility of Soils》2000,31(5):436-440
Microcosms were used to determine the influence of N additions on active bacterial and active fungal biomass, cellulose degradation
and lignin degradation at 5, 10 and 15 weeks in soils from blackwater and redwater wetlands in the northern Florida panhandle.
Blackwater streams contain a high dissolved organic C concentration which imparts a dark color to the water and contain low
concentrations of nutrients. Redwater streams contain high concentrations of suspended clays and inorganic nutrients, such
as N and P, compared to blackwater streams. Active bacterial and fungal biomass was determined by direct microscopy; cellulose
and lignin degradation were measured radiometrically. The experimental design was a randomized block. Treatments were: soil
type (blackwater or redwater forested wetlands) and N additions (soils amended with the equivalent of 0, 200 or 400 kg N ha–1 as NH4NO3). Redwater soils contained higher concentrations of C, total N, P, K, Ca, Mn, Fe, B and Zn than blackwater soils. After N
addition and 15 weeks of incubation, the active bacterial biomass in redwater soils was lower than in blackwater soils; the
active bacterial biomass in blackwater soils was lower when 400 kg N ha–1, but not when 200 kg N ha–1, was added. The active fungal biomass in blackwater soils was higher when 400 kg N ha–1, but not when 200 kg N ha–1, was added. The active fungal biomass in redwater wetland soils was lower when 200 kg N ha–1, but not when 400 kg N ha–1, was added. Cellulose and lignin degradation was higher in redwater than in blackwater soils. After 10 and 15 weeks of incubation,
the addition of 200 or 400 kg N as NH4NO3 ha–1 decreased cellulose and lignin degradation in both wetland soils to similar levels. This study indicated that the addition
of N may slow organic matter degradation and nutrient mineralization, thereby creating deficiencies of other plant-essential
nutrients in wetland forest soils.
Received: 7 April 1999 相似文献