首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 15 毫秒
1.
A long-term soil fertility experiment (1988-1999) at the Regional Agricultural Research Station, Bhairhawa, Nepal, was analysed to determine: (1) how long the yields of rice (Oryza sativa L.) and wheat (Triticum aestivum L.) can be sustained without K but with N and N+P (NP) applied with or without farmyard manure (FYM) and green manure, and (2) the impact of K application on yields. Starting from the 1995 wheat season, the experiment was modified to accommodate K at 0, 42, and 84 kg ha-1 in plots receiving NP to study the response of rice and wheat to K. Both rice and wheat responded to K application but the response of wheat was substantially higher, indicating that the availability of native K may have been lower in wheat. Rice yields were lower in treatments without P than with P, and yields declined significantly (0.11-0.20 Mg ha-1 year-1) in all the treatments except in NP and NP+FYM. Wheat yield was more adversely affected than rice yield when P and K were not applied. In addition, wheat yields were low (average 0.5-2.1 Mg ha-1 in various treatments). Wheat yields declined (0.08-0.12 Mg ha-1 year-1) in all but FYM treatments indicating the role of FYM in sustaining yields. The interaction of K deficiency with Helminthosporium leaf blight (spot blotch and tan spot) is also suggested as one of the factors limiting wheat yields. The estimated K balance in soil was highly negative. Results suggest that farmers should apply adequate amount of K for higher and sustainable rice and wheat yields.  相似文献   

2.
Use of renewable N and C sources such as green manure (GM) and crop residues in rice-wheat cropping systems of South Asia may lead to higher crop productivity and C sequestration. However, information on measurements of gaseous N losses (N2O+N2) via denitrification and environmental problems such as N2O and CO2 production in rice-wheat cropping systems is not available. An acetylene inhibition-intact soil core technique was employed for direct measurement of denitrification losses, N2O and CO2 production, in an irrigated field planted to rice (Oryza sativa L.) and wheat (Triticum aestivum L.) in an annual rotation. The soil was a coarse-textured Tolewal sandy loam soil (Typic Ustochrept) and the site a semi-arid subtropical Punjab region of India. Wheat residue (WR, C:N=94) was incorporated at 6 t ha-1 and sesbania (Sesbania aculeata L.) was grown as GM crop for 60 days during the pre-rice fallow period. Fresh biomass of GM (C:N.=18) at 20 or 40 t ha-1 was incorporated into the soil 2 days before transplanting rice. Results of this study reveal that (1) denitrification is a significant N loss process under wetland rice amounting to 33% of the prescribed dose of 120 kg N ha-1 applied as fertilizer urea-N (FN); (2) integrated management of 6 t WR ha-1 and 20 t GM ha-1 supplying 88 kg N ha-1 and 32 kg FN ha-1 significantly reduced cumulative gaseous N losses to 51.6 kg N ha-1 as compared with 58.2 kg N ha-1 for 120 kg FN ha-1 alone; (3) application of excessive N and C through applying 40 t GM ha-1 (176 kg N ha-1) resulted in the highest gaseous losses of 70 kg N ha-1; (4) the gaseous N losses under wheat were 0.6% to 2% of the applied 120 kg FN ha-1 and were eight- to tenfold lower (5-8 kg N ha-1) than those preceding rice; (5) an interplay between the availability of NO3- and organic C largely controlled denitrification and N2O flux during summer-grown flooded rice whereas temperature and soil aeration status were the primary regulators of the nitrification-denitrification processes and gaseous N losses during winter-grown upland wheat; (6) the irrigated rice-wheat system is a significant source of N2O as it emits around 15 kg N2O-N ha-1 year-1; (7) incorporation of WR in rice and rice residue (C:N=63) in wheat increased soil respiration, and increased CO2 production in WR- and GM-amended soils under anaerobic wetland rice coincided with enhanced rates of denitrification; and (8) with adequate soil moisture, most of the decomposable C fraction of added residues was mineralized within one crop-growing season and application of FN and GM further accelerated this process.  相似文献   

3.
Two field experiments were conducted in 1999 (wet season) and 2000 (dry season) on a Ustic Endoaquerts in central Thailand to examine the impact of rice straw management practices on rice yield, N uptake and fertilizer-N use efficiency. Treatments included a combination of urea broadcast at a rate of 70 kg N haу with either straw or compost which were incorporated at a rate of 5 Mg haу. At maturity of the wet season rice, 15N recovery by the grain was low (11-14%) as well as straw-N derived from labeled N (5-7%). After harvest, 25-29% of applied N still remained in the soil, mainly in the 0 to 5-cm layer. Large amounts of fertilizer-N (53-55%) were lost (unaccounted for) from the soil/plant system during the first crop. Residual fertilizer-N recovery in the second rice crop was less than 3% from the original application. During both fallow seasons NO3m-N remained the dominant form of mineral N (NO3m + NH4+) in the soil but its concentration was low. In the wet season grain yield response to N application was significant (P =0.05). Organic material sources did not significantly change grain yield and N accumulation in rice. In terms of grain yield and N uptake at maturity, there was no significant residual effect of fertilizer-N on the subsequent rice crop. These results indicated that the combined use of organic residues with urea did not decrease total N losses or increase crop yield or uptake of N compared to urea alone.  相似文献   

4.
A field study was conducted to investigate the effects of N fertilization on soil N pools and associated microbial properties in a 13-year-old hoop pine (Araucaria cunninghamii) plantation of southeast Queensland, Australia. The treatments included: (1) control (without N application); (2) 300 kg N ha-1 applied as NH4NO3; and (3) 600 kg N ha-1 as NH4NO3. The experiment employed a randomized complete block design with four replicates. Soil samples were taken approximately 5 years after the N application. The results showed that application of 600 kg N ha-1 significantly increased concentrations of NH4+-N in 0-10 cm soil compared with the control and application of 300 kg N ha-1. Concentrations of NO3--N in soil (both 0-10 cm and 10-20 cm) with an application rate of 600 kg N ha-1 were significantly higher compared with the control. Application of 600 kg N ha-1 significantly increased gross N mineralization and immobilization rates (0-10 cm soil) determined by 15N isotope dilution techniques under anaerobic incubation, compared with the control. However, N application did not significantly affect the concentrations of soil total C and total N. N application appeared to decrease microbial biomass C and N and respiration, and to increase the metabolic quotient (qCO2) in 0-10 cm soil, but these effects were not statistically significant. The lack of statistical significance in these microbial properties between the treatments might have been associated with large spatial variability between the replicate plots at this experimental site. Spatial variability in soil microbial biomass C and N was found to relate to soil moisture, total C and total N.  相似文献   

5.
In a greenhouse trial, rice (Oryza sativa L.) cultivar Pusa Basmati-1 was grown in a Zn-deficient Typic Ustochrept soil from IARI farm, New Delhi, India. The experimental design included two rates of inoculation with vesicular-arbuscular mycorrhizal fungi (VAMF), Glomus etunicatum (nil and inoculated) and different combinations of organic (farmyard manure, FYM) and inorganic (NPK, ZnSO4) fertilizers. The results revealed that a high intensity of root colonization in rice inoculated with G. etunicatum could be achieved by raising seedlings in P- and Zn-deficient soil in the nursery under aerobic conditions. Moreover, the VAMF that infected rice seedlings in the nursery also survived when the same seedlings were transplanted into pots under waterlogged conditions. The application of ZnSO4 significantly increased the inflow of Zn to rice roots at the panicle-initiation stage (40 days after transplanting) relative to NPK. The former treatment also increased root length, root weight, root volume and total uptake of Zn and thereby increased the grain and dry matter yields. Alternatively, these variables were substantially enhanced by inoculating rice with the VAMF, G. etunicatum. The VAMF-colonized rice plants were more active in acquiring Zn from either added or native sources than non-colonized plants, and consequently the available-Zn content in soil was lower after the harvest of rice.  相似文献   

6.
A pot experiment with a loam soil and spring wheat as test crop showed that an application of dicyandiamide (DCD), and especially its combination with hydroquinone (HQ), gave a much larger recovery of soil urea-15N than treatments based on the application of urea alone or urea plus HQ. Most of the urea-15N applied to soil was present as organic plus chemically fixed 15N in the DCD and DCD plus HQ treatments. These two treatments showed the smallest accumulation of urea-derived (NO3-+NO2-)-15N. Under well-drained conditions, there was a synergistic effect of the nitrification inhibitor DCD and the urease inhibitor HQ on urea-15N transformations and the recovery of fertilizer 15N in soil after the application of urea.  相似文献   

7.
太湖地区稻麦轮作条件下施用包膜尿素的氮素循环和损失   总被引：8，自引：0，他引：8  
A field experiment was conducted to investigate the fate of ^15N-labeled urea and its residual effect under the winter wheat （Triticum aestivum L.） and summer maize （Zea mays L.） rotation system on the North China Plain. Compared to a conventional application rate of 360 kg N ha^-1 （N360）, a reduced rate of 120 kg N ha^-1 （N120） led to a significant increase （P 〈 0.05） in wheat yield and no significant differences were found for maize. However, in the 0-100 cm soil profile at harvest, compared with N360, N120 led to significant decreases （P 〈 0.05） of percent residual N and percent unaccounted-for N, which possibly reflected losses from the managed system. Of the residual fertilizer N in the soil profile, 25.6%-44.7% and 20.7%-38.2% for N120 and N360, respectively, were in the organic N pool, whereas 0.3%-3.0% and 11.2%-24.4%, correspondingly, were in the nitrate pool, indicating a higher potential for leaching loss associated with application at the conventional rate. Recovery of residual N in the soil profile by succeeding crops was less than 7.5% of the applied N. For N120, total soil N balance was negative; however, there was still considerable mineral N （NH4^＋-N and NO3^--N） in the soil profile after harvest. Therefore, N120 could be considered ngronomically acceptable in the short run, but for long-term sustainability, the N rate should be recommended based on a soil mineral N test and a plant tissue nitrate test to maintain the soil fertility.  相似文献   

8.
Leaves of nine green manure (GM) species were surface applied to a tropical volcanic-ash soil at a rate of 100 kg N ha-1 in order to evaluate their N-fertilizer value in a glasshouse experiment. GM treatments were compared to urea at two rates, 50 kg N ha-1 (FN50) and 100 kg N ha-1 (FN100), and to a control with no fertilizer application (FN0). Two weeks after treatment application, upland rice seedlings were sown in order to conduct N uptake studies. Soil volumetric moisture content was maintained close to 50%. In general, soil showed an initial increase in inorganic N followed by a rapid decline with time. After 2 weeks of evaluation FN100, FN50 and leaves of Mucuna pruriens var. Tlaltizapan and Indigofera constricta presented higher values of inorganic N (157-109 mg N kg-1 soil); while, FN0 and leaves of Mucuna deerengianum, Cratylia argentea and Calliandra calothyrsus presented lower values (75-89 mg N kg-1 soil). N recovery by rice, at 20 weeks after planting, was highest for FN100 (59.9%) followed by Canavalia brasiliensis (54.6%), Calliandra calothyrsus (47.4%) and M. pruriens var. IITA-Benin (32.4%); while, M. pruriens var. Tlaltizapan, FN50, Tithonia diversifolia and I. constricta presented lower N uptake (13-20%). Significant relationships were found between some quality parameters of GM evaluated (i.e. total N, fibers, lignin and polyphenol content), soil N availability and rice N uptake. These results suggest that GM that decomposed and released N slowly resulted in high N uptake when they were used at pre-sowing in a tropical volcanic-ash soil.  相似文献   

9.
The objectives of this study were to determine the variability in mineralization of dairy manure N, to determine if N mineralization can be predicted by compositional factors or by near- or mid-infrared reflectance spectroscopy. Dairy manures (n =107) were collected from farms in Maryland, Virginia, Pennsylvania, New York, and Connecticut. The composition of these manures ranged from 14 to 386 g dry matter kg-1, 0.9 to 9.5 kg total N/m3, and 0.3 to 4.7 kg NH4+-N/m3. Manure-amended soil was aerobically incubated at 25°C and concentrations of NH4+-N and NO3--N were determined at day 2 and day 56. The manures were highly variable in their N mineralization characteristics, ranging from a net mineralization of 54.9% to a net immobilization of 29.2% of the organic N. When compositional parameters were individually regressed against percentage mineralized organic N, the highest correlation coefficient (r) was 0.164. A stepwise regression of all 11 variables yielded a maximal r of 0.486. These results suggest that the availability of dairy manure organic N is highly variable and that the availability cannot be predicted from simple compositional parameters. No relationship was found between near-infrared spectral characteristics and N mineralization suggesting that no simple relationship exists between N mineralization and compositional characteristics. There appears to be some potential for the use of mid-infrared for determining the mineralization potential of manures.  相似文献   

10.
A field experiment was conducted with wetland rice (Oryza sativa cv. IR-36) in a sandy clay loam soil (Entisol) to study the effect of inoculation with a soil-based mixed culture of four diazotrophic cyanobacteria,Aulosira fertilissima, Nostoc muscorum, N. commune andAnabaena spp., on the N-flux in inorganic NH4 ++NO3 ?+ NO2 ?), easily oxidizable, hydrolysable and non-hydrolysable forms of N in soil during vegetative growth periods of the crop. Effects on grain and straw yield and N uptake by the crop were estimated. The effects of applying urea N and N as organic sources, viz.Sesbania aculeata, Neem (Azardirachta indica) cake and FYM, each at the rate of 40 kg N ha?1, to the soil were also evaluated. Inoculation significantly increased the release of inorganic N, evidenced by its increased concentrations either in soil or in soil solution. However, such increases rarely exceeded even 4% of total N gained in different froms in the soil system by inoculation during the vegetative growth stages of the rice plant, when the nutritional requirement of the plants is at a maximum. Most of the N2 fixed by cyanobacteria remained in the soil as the hydrolysable form (about 85%) during this period. Inoculation caused an insignificant increase in grain (8%) and straw (11%) yield, which was, however, accompanied by a significant increase in N uptake by the grain (30%) and an increase in total uptake of 15.3 kg N ha 1. Such beneficial effects of inoculation varied in magnitude with the application of organic sources, with farmyard manure (FYM) being the most effective. Application of urea N, on the other hand, markedly reduced such an effect.  相似文献   

11.
Manure N dynamics are affected by manure characteristics, soil factors, and environmental conditions. An incubation experiment was conducted to assess the relationship of these factors. The effects of temperature (11, 18, and 25°C), soil texture (three soils, silt loam to sandy loam), and soil water status (constant at 60% water filled pore space, WFPS, and fluctuating between 30% and 60% WFPS) on net mineralization and nitrification of swine manure N were assessed. Swine manure was applied at an equivalent rate of 350 kg total N ha-1 to 250 g air-dry soil in 2-l canning jars. Subsamples were taken from each jar for NO3- and NH4+ determination when fluctuating moisture treatment dried to 30% WFPS, with sampling continuing through four wet-dry cycles at each temperature. Manure NH4+ was rapidly nitrified to NO3-. The relationship between NO3- accumulation and degree days after application (DDAA, 0°C base) could be described across temperatures using a single pool exponential model for each soil. More NO3- accumulated in coarser-textured soils (150-200 mg N kg-1 soil), compared to 130 mg N kg-1 soil in the silt loam soil. Fluctuating soil water status did not alter estimates of rate and extent of NO3- accumulation, but slowed NH4+ disappearance somewhat.  相似文献   

12.
The mineralisation of green manure from agroforestry trees was monitored with the objective to compare the temporal dynamics of mineralisation of litter from different species. Green manures from five agroforestry tree species were used on a fallow field during the long rainy season of 1997 (March-August) and from two species in the following short rainy season (September-January) in western Kenya. Different methods, i.e. measurements of isotopic ratios of C in respired CO2 and of soil organic matter (SOM) fractions, soil inorganic N and mass loss from litterbags, were used in the field to study decomposition and C and N mineralisation. Soil respiration, with the separation of added C from old soil C by using the isotopic ratio of 13C/12C in the respired CO2, correlated well with extractable NH4+ in the soil. Mineralisation was high and very rapid from residues of Sesbania sesban of high quality [e.g. low ratio of (polyphenol+lignin)/N] and low and slow from low quality residues of Grevillea robusta. Ten days after application, 37% and 8% of the added C had been respired from Sesbania and Grevillea, respectively. Apparently, as much as 70-90% of the added C was respired in 40 days from high quality green manure. Weight losses of around 80%, from high quality residues in litterbags, also indicate substantial C losses and that a build-up of SOM is unlikely. For immediate effects on soil fertility, application of high quality green manure may, however, be a viable management option. To achieve synchrony with crop demand, caution is needed in management as large amounts of N are mineralised within a few days after application.  相似文献   

13.
During freeze-thaw events, biophysical changes occurring in soils can affect processes such as mineralization, nitrification and denitrification which control inorganic N balances in agro-ecosystems. To evaluate the impact of these climatic events on soil biochemical properties, a study was conducted comparing soil denitrification enzyme activity (DEA), dissolved organic C (DOC) and inorganic N levels before and after the winter season in plots under: (1) continuous corn (Zea mays L.) (CC) with annual chisel plow and disking, (2) corn-soybean (Glycine max L.) (CS) rotation with chisel plow every other year prior to planting soybean, and (3) corn-soybean-wheat (Triticum aestivum L.)/hairy vetch (Vicia villosa Roth) (CSW-V) with ridge tillage during the corn and soybean crops, and dairy manure application during the corn year. Soil cores were collected in late autumn and immediately after spring thaw at 0-5, 5-10, 10-15, and 15-30 cm depths. Regardless of management practices, freeze-thaw events resulted in significant (2-10 times) increases in NH4+-N, NO3--N (P<0.001) and DOC (P<0.01) levels at all soil depths. Following freeze-thaw, DEA remained unchanged in the 5-30 cm depth but dropped significantly (P<0.01) in the 0-5 cm soil layer. In that layer, soils which had been chisel plowed during the previous growing season lost 78-84% of the DEA recorded during the fall, whereas in the plots amended with manure during the previous season, the loss of activity was 40-45%. These data indicate that frequent tillage, compared with manure additions, is more conducive to overwinter loss of DEA in surface layers of soils subject to freeze-thaw cycles.  相似文献   

14.
An incubation experiment was conducted to study N2O emissions from a Typic Ustochrept, alluvial soil, fertilized with urea and urea combined with different levels of two nitrification inhibitors, viz karanjin and dicyandiamide (DCD). Karanjin [a furano-flavonoid, obtained from karanja (Pongamia glabra Vent.) seeds] and DCD were incorporated at rates of 5, 10, 15, 20 and 25% of applied urea-N (100 mg kg-1 soil), to the soil adjusted to field capacity moisture content. The highest N2O flux (366 µg N2O-N kg-1 soil day-1) was obtained on day 1 after incubation from soil fertilized with urea without any inhibitor. The presence of the inhibitors appreciably reduced the mean N2O flux from the urea-treated soils. The application of karanjin resulted in a higher mitigation of total N2O-N emission (92-96%) compared to DCD (60-71%). Rates of N2O flux ranged from 0.9 to 140 µg N2O-N kg-1 soil day-1 from urea combined with different levels of the two inhibitors (coefficient of variation=24-272%). Karanjin (62-75%) was also more effective than DCD (9-42%) in inhibiting nitrification during the 30-day incubation period.  相似文献   

15.
以典型半干旱区干湿砂质新成土（Ust-Sandic Entisols）为供试土壤进行田间试验,研究地膜覆盖、施氮及补充灌水量对春玉米（Zea mays L.）产量、土壤矿质氮（NO3--N和NH4+-N）及氮素平衡的影响。结果表明,0—100 cm土体范围内,随着土层加深,播前和收获后土壤NO3--N含量呈降低趋势,NH4+-N有所增加,但变幅不大;总矿质氮量（NO3--N和NH4+-N）表现为下降。说明地膜覆盖和施氮并没有使NO3--N深层累积量增加,这可能与土壤本身供氮能力严重不足有关。与不施氮相比,施氮各处理氮肥表观损失量增加;与不覆膜相比,作物氮素累积量比不覆膜显著增加（P0.05）。在低灌（80 mm）覆膜和高灌（160 mm）覆膜条件下,玉米的氮肥利用率均比不覆膜均提高了18.8%,说明覆膜低灌在相同施氮条件下,可节约80 mm灌水。但低灌（80 mm）与高灌（160 mm）不覆膜间氮肥利用率差异不显著,表明在相同施氮条件下,覆膜可有效提高氮肥利用率,减少氮素损失。综合考虑籽粒产量和氮肥利用率,“覆膜+补灌80 mm+施氮90 kg/hm2”可能为本试验条件下较优的栽培模式。  相似文献   

16.
元素硫和双氰胺对菜地土壤铵态氮硝化抑制协同效应研究   总被引：4，自引：0，他引：4  
采用好气培养法,研究了双氰胺（DCD）、元素硫（S0）和元素硫分解中间物（S2O32-）及其组合对蔬菜地土壤氮素硝化抑制作用。结果表明,在培养试验72 d内,DCD+S0、DCD、DCD+ Na2S2O3处理土壤NH4+-N总量分别是N处理的5. 8、5.1、5.9倍;S0、Na2S2O3处理分别是N处理的1.8、1.4倍;而所有硝化抑制剂（DCD、S0、S2O32-）处理土壤NO3--N含量显著低于N处理,表明DCD、S0和S2O32-均能抑制菜地土壤铵态氮硝化。培养试验开始8 d后,Na2S2O3和DCD对铵态氮硝化抑制产生协同效应,16 d后S0和DCD对铵态氮硝化抑制也产生协同效应,这可能是由于S0 氧化中间体S2O32-、S4O62-具有抑制DCD降解作用,延长了DCD硝化抑制作用时间。建议蔬菜生产上推荐使用DCD+S0组合,以提高氮素利用率。  相似文献   

17.
Applications of dairy farm effluents to land may lead to ammonia (NH3) volatilization and nitrous oxide (N2O) emissions. Nitrogen (N) transformation process inhibitors, such as urease inhibitors (UIs) and nitrification inhibitors (NIs), have been used to reduce NH3 and N2O losses derived from agricultural N sources. The objective of this study was to examine the effects of amending dairy effluents with UI (N-(n-butyl) thiophosphoric triamide (NBTPT)) and NI (dicyandiamide (DCD)) on NH3 and N2O emissions. Treatments included either fresh or stored manure and either fresh or stored farm dairy effluent (FDE), with and without NBTPT (0.25 g kg?1 N) or DCD (10 kg ha?1), applied to a pasture on a free-draining volcanic parent material soil. The nutrient loading rate of FDE and manure, which had different dry matter contents (about 2 and 11 %, respectively) was 100 kg N ha?1. Application of manure and FDE led to NH3 volatilization (15, 1, 17 and 0.4 % of applied N in fresh manure, fresh FDE, stored manure and stored FDE, respectively). With UI (NBTPT), NH3 volatilization from fresh manure was significantly (P?<?0.05) decreased to 8 % from 15 % of applied N, but the UI did not significantly reduce NH3 volatilization from fresh FDE. The N2O emission factors (amount of N2O–N emitted as a percentage of applied N) for fresh manure, fresh FDE and stored FDE were 0.13?±?0.02, 0.14?±?0.03 and 0.03?±?0.01 %, respectively. The NI (DCD) was effective in decreasing N2O emissions from stored FDE, fresh FDE and fresh manure by 90, 51 and 46 % (P?<?0.05), respectively. All types of effluent increased pasture production over the first 21 days after application (P?<?0.05). The addition of DCD resulted in an increase in pasture production at first harvest on day 21 (P?<?0.05). This study illustrates that UIs and NIs can be effective in mitigating NH3 and N2O emissions from land-applied dairy effluents.  相似文献   

18.
A long-term field experiment was conducted at the research farm of the All-India Coordinated Research Project for Dryland Agriculture, Phulbani, Orissa, India, from 2001 to 2006 to identify the best integrated nutrient-use treatments for ensuring greater productivity, profitability, sustainability, and improved soil quality in pigeon pea + rice (two rows of pigeon pea followed by five rows of rice alternately) intercropping system. In all, nine treatments, eight comprising integrated nutrient-use practices, chemical fertilizer (CF), farmyard manure (FYM), and green leaf manure (GLM) to supply nitrogen (N) at 45 kg N ha–1 and one farmer's practice equivalent to 25 kg N ha–1 (FYM 5 t ha–1), were tested on a long-term basis. Results of the study revealed that 20 kg N ha–1 (FYM) + 25 kg N (CF) gave maximum mean rice grain yield of 1.52 t ha–1, followed by 20 kg N (GLM) + 25 kg N (urea) with grain yield of 1.51 t ha–1. In the case of pigeon pea, 30 kg N (FYM) +15 kg N (urea) gave maximum pigeon pea grain yield of 0.94 t ha–1, which was 34% greater than the sole application of chemical fertilizer. Pigeon pea grain yield tended to increase with increasing proportion of organic N in FYM + CF or GLM + CF combinations. Application of 20 kg N (FYM) + 25 kg N (urea) recorded maximum mean rice equivalent yield of 3.59 t ha–1 and sustainability yield index of 59%. While studying profitability, application of 20 kg N (FYM) + 25 kg N (CF) gave maximum net returns of US$168.94 ha–1. Impact of treatments on soil quality as assessed in terms of relative soil quality indices (RSQI) increased with increasing proportion of organic sources of N. Using an innovative and new approach, an index of integrated productivity–sustainability–profitability–soil quality performance index (I P,S,Pr,SQ) was computed to make a precise evaluation of the treatments. Based on this index, the order of performance of the treatments was T6 [20 N (FYM) + 25 N (CF)] (7.7) > T7 [30 N (FYM) + 15 N (CF) (6.9)] > T3 [20 N (GL) + 25 N (CF)] (6.8) > T5 [10 N (FYM) + 35 N (CF) (6.6)] > T9 [GL] (6.5) > T8 [CF] (6.2) > T4 [30 N (GL) + 15 N (CF)] (6.0) > T2 [10 N (GL) + 35 N (CF)] (5.7) > T1 [FYM at 5 t ha–1] (4.1). Thus, the results and the methodology adopted in this study using long-term data would be very useful to researchers, farmers, land managers, and other stakeholders not only in India but also across the world under similar climatic and edaphic situations.  相似文献   

19.
A field experiment was conducted with wetland rice (Oryza sativa cv. IR-36) in a sandy clay loam soil (Entisol) to study the effect of inoculation with a soil-based mixed culture of four diazotrophic cyanobacteria,Aulosira fertilissima, Nostoc muscorum, N. commune andAnabaena spp., on the N-flux in inorganic NH4 ++NO3 –+ NO2 –), easily oxidizable, hydrolysable and non-hydrolysable forms of N in soil during vegetative growth periods of the crop. Effects on grain and straw yield and N uptake by the crop were estimated. The effects of applying urea N and N as organic sources, viz.Sesbania aculeata, Neem (Azardirachta indica) cake and FYM, each at the rate of 40 kg N ha–1, to the soil were also evaluated. Inoculation significantly increased the release of inorganic N, evidenced by its increased concentrations either in soil or in soil solution. However, such increases rarely exceeded even 4% of total N gained in different froms in the soil system by inoculation during the vegetative growth stages of the rice plant, when the nutritional requirement of the plants is at a maximum. Most of the N2 fixed by cyanobacteria remained in the soil as the hydrolysable form (about 85%) during this period. Inoculation caused an insignificant increase in grain (8%) and straw (11%) yield, which was, however, accompanied by a significant increase in N uptake by the grain (30%) and an increase in total uptake of 15.3 kg N ha 1. Such beneficial effects of inoculation varied in magnitude with the application of organic sources, with farmyard manure (FYM) being the most effective. Application of urea N, on the other hand, markedly reduced such an effect.  相似文献   

20.
Abstract

Contribution of sesbania green manure, rice straw, and FYM (farm yard manure) was studied along with that of urea and A/SO4 (ammonium sulphate) for the cultivation of lowland rice and for the residual soil fertility. The results revealed that A/SO4 application resulted in a larger number of productive tillers, higher straw production, and higher grain yield compared to urea. Among the organic manures, sesbania green manure and FYM exerted almost similar effects on the number of productive tillers and paddy yield while the yield increase compared to the incorporation of rice straw. A similar affect of these organic manures on nitrogen uptake by rice straw, grain, and straw + grain was observed. Additional uptake of N due to the application of sesbania green manure, FYM and rice straw amounted to 15, 13, and 2.85 kg ha?1, respectively. Residual N fertility was the highest when of sesbania green manure was applied followed by FYM and rice straw. Residual P fertility was higher in the case of FYM than other treatments whereas the residual K fertility was the highest in the case of rice straw incorporation.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号