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1.
太湖地区水稻追肥的氨挥发损失和氮素平衡   总被引:8,自引:0,他引:8  
采用密闭室通气法和15N 微区试验, 对太湖地区水稻不同生育期追施氮肥的氨挥发损失、水稻对氮肥的吸收利用和土壤氮素残留情况进行了研究。结果表明, 氨挥发损失主要发生在施肥后1 周内, 峰值出现在施肥后1~2 d, 氨挥发速率变化与田面水NH4+-N 浓度变化规律一致, 分蘖肥和穗肥氨挥发损失率分别为16.7%和6.3%; 水稻分蘖肥的作物氮素利用率低于穗肥, 分别为36.7%和49.6%, 主要原因是穗肥的氨挥发损失较少,并且更易于向籽粒转移; 2 次追施氮肥的表观损失率分别为52.8%和40.7%; 在土壤中残留肥料氮为10.6%, 大都集中在0~20 cm 土壤中, 耕层以下较少。本结果表明, 在水稻孕穗时期施氮肥有利于提高氮肥利用效率、减少氮肥损失, 主要体现在穗肥拥有较低的氨挥发损失率和较高的籽粒利用率。  相似文献   

2.
氮肥去向的研究--Ⅰ.稻田土壤中氮肥的去向   总被引:4,自引:0,他引:4  
陈荣业  朱兆良 《土壤学报》1982,19(2):122-130
氮肥施入土壤后的去向,直接关系到作物增产和环境保护,是农业和环境科学研究中的基本资料。对氮肥去向的研究,以在田间条件下进行的意义比较大。因此,1978-1980年,我们在华东地区三种不同土壤上,采用田间微区15N示踪的方法,分别测定了施用于水稻和小麦的几种常用氮肥的去向,并以尿素为重点,研究了施肥方法、施肥时期、土壤水分状况以及硝化抑制剂等对氮肥去向的影响。所得结果将分别整理。本文是稻田试验方面的初步总结。  相似文献   

3.
On irrigated agricultural soils from semi-arid and arid regions, ammonia (NH3) volatilization and nitrous oxide (N2O) emission can be a considerable source of N losses. This study was designed to test the capture of 15N loss as NH3 and N2O from previous and recent manure application using a sandy, calcareous soil from Oman amended one or two times with 15N labeled manure to elucidate microbial turnover processes under laboratory conditions. The system allowed to detect 15N enrichments in evolved N2O-N and NH3-N of up to 17% and 9%, respectively, and total N, K2SO4 extractable N and microbial N pools from previous and recent 15N labeled manure applications of up to 7%, 8%, and 15%. One time manured soil had higher cumulative N2O-N emissions (141 µg kg?1) than repeatedly manured soil with 43 µg kg?1 of which only 22% derived from recent manure application indicating a priming effect.  相似文献   

4.
在特制密闭盆钵甲,研究了15N标记氮肥作水稻基肥混施时,氨的挥发及其在氮素损失中的重要性,随着通气速率的增高,氨的挥发及其在氮素损失中的重要性也增大,至换气频率达15-20次/分时即接近或达到最大值.在酸性水稻土上,硫铵的氮素损失的主要途径是反硝化作用,特别是气温较低的月份;尿素的氮素损失途径,在气温较低的月份中以反硝化作用为主,在温度较高的月份中,则氨的挥发与反硝化作用都是重要的;对碳铵来说,氨的挥发和反硝化作用都是氮素损失的重要途径.在石灰性土壤上,碳铵的氮素损失的主要途径是氨的挥发,而在硫铵和尿素的氮素损失中,氨的挥发和反硝化作用则都是重要的.  相似文献   

5.
Abstract

Nitrogen (N) loss in the form of volatilized ammonia (NH3) is a considerable problem when ammonium (NH4 +) forming fertilizers are applied to calcareous or alkaline soils. The volatilization of NH3 from urea phosphate (UP) and urea (U) was studied on three selected soils (Hayhook SL, Laveen L, and Latene L) with the use of a laboratory aeration system. Urea phosphate and U were each applied at rates of 0, 50, 100, and 200 mg N kg‐1 soil, either to the surface dry or in solution or mixed with the soil. The volatilized NH3 was trapped in sulfuric acid, sampled periodically, and analyzed for N with the semi microkjeldahl distillation apparatus.

The highest N loss in the form of NH3 occurred when U was applied to Hayhook soil (neutral to acidic, coarse textured, and low CaCO3 content). However, UP applied to Hayhook soil resulted in the lowest NH3‐N loss. Less NH3‐N loss was found from U application to Laveen and Latene soils (fine textured with higher CaCO3 content) than with Hayhook soil. The general trend was higher N loss when a surface application was made, either dry or in solution, than when the fertilizer was mixed with the soil. This trend showed an increase in the amount of volatilized NH3 with increasing N application rates.

Generally, UP is a potential fertilizer for supplying N and phosphorus (P) as plant nutrients with a low potential for losses due to NH3 volatilization.  相似文献   

6.
猪粪沼液施用对土壤氨挥发及玉米产量和品质的影响   总被引:8,自引:0,他引:8  
猪粪沼液含有大量的养分,如氮、磷、钾、氨基酸、腐植酸等,但如果不及时施用,也会带来水体富营养化问题。沼液替代化肥是目前最有效的利用方式。采用田间试验方法,在春、夏两季玉米上,研究了猪粪沼液不同用量与不同运筹对土壤氨挥发损失以及玉米产量、品质等的影响。结果表明,夏玉米基施猪粪沼液氨挥发量大于春玉米,沼液的氨挥发量明显大于化肥,且沼液施用量越大,氨挥发量越大;由氨挥发导致的氮素损失量占施肥量的0.17%~2.16%,平均为0.88%。在春玉米中,单独施用化肥以及化肥与沼液各50%配施处理的产量分别为901.55 kg.667m?2和892.71 kg.667m?2,显著高于其他处理;纯化肥处理可溶性糖为103.69 g.kg?1,显著低于其他处理;纯化肥处理皮渣率为9.87%,显著高于其他处理;其他品质指标各处理间无显著差异。在夏玉米中,总体产量不如春玉米,纯化肥处理产量为523.47 kg,显著高于其他处理,化肥与沼液各50%配施处理的产量仅次于纯化肥处理,为513.41 kg。纯化肥处理的玉米品质总体上高于纯沼液处理,但沼液和化肥各50%处理玉米品质与纯化肥处理无明显差异。可见,对玉米植物而言,以50%沼液替代化学肥料,在技术上可行,可以获得与化肥处理相同的玉米产量与品质。  相似文献   

7.
涂层尿素在石灰性土壤上的行为   总被引:6,自引:1,他引:6  
本项试验主要探索涂层尿素在石灰性土壤上的变化规律。试验结果表明,在三种不同水分含量条件下(10%、15%、20%),涂层尿素施入土壤后氨挥发速率均比普遍尿素低;涂层尿素施入土壤随即浇水,有良好的随水移动性能,肥料氮在土体中的移动深度和肥料氮的回收率随浇水量的不同表现出明显的差异;涂层尿素肥料氮的回收率比普通尿素高2.28个百分点。涂层尿素做底肥时,在小麦上的利用率比普通尿素高3.4个百分点,在玉米上高5.18个百分点;底、追结合施用涂层尿素在小麦上的利用率比普通尿素高5.6个百分点,在玉米上高9.5个百分点。涂层尿素在小麦和玉米上施用,其氮素的损失率比普通尿素低5.4~11.4个百分点。在种植小麦条件下涂层尿素施入土壤后,肥料矿化和供氮特征表现为小麦生长前期0~40Cm土层中速效氮含量低于普通尿素,小麦起身拔节以后,速效氮含量则高于普通尿素。  相似文献   

8.
Abstract

The loss of ammonia by volatilization during incubation and soil drying and contamination of soil samples during drying were studied in the laboratory. Aqua ammonia placement treatments produced a range of soil nitrate and ammonium levels, which produced different amounts of ammonia upon incubation and drying. Recovery of applied N as mineral N and volatilized N in acid traps was virtually complete, indicating that ammonia volatilization was the only significant N loss process. When aqua ammonia was applied to the surface, 57% was volatilized, compared with only 2% when the fertilizer was deep placed. Ammonia volatilization decreased with time; most of the loss occurred during the first day after fertilizer application and ammonia loss was virtually complete within 8 days of incubation. Regression analysis indicated loss of ammonia on soil drying could be explained by the initial ammonia concentration and the time from fertilizer application; approximately 40 days from fertilizer application were required for complete chemical adsorption of ammonia (i.e. no ammonia loss on drying).

Unfertilized soils absorbed up to 66 mg N/kg of the ammonia volatilized from fertilized soils when dried together in the same oven. We conclude that where accurate ammonium analysis is required on recently fertilized soil, undried soil should be used. This eliminates ammonia loss during drying and cross‐contamination of samples. Drying of soil did not affect the recovery of nitrate N, as nitrate was not volatilized or denitrified.  相似文献   

9.
Summary The relative importance of ammonia volatilization and denitrification as loss processes following the application of urea to flooded rice by the traditional method was assessed at four sites with different characteristics in the Philippines. The effect of reducing ammonia loss on denitrification and total N loss was also studied. The total N loss was determined by a 15N-balance method and ammonia volatilization was assessed by a bulk aerodynamic method following the application of urea to small plots (4.8×5.2 m). As run-off was prevented and leaching losses were negligible, the denitrification loss was assessed as the difference between total N loss and ammonia loss. When urea was broadcast into the floodwater at transplanting, the ammonia loss varied from 10% to 56% of the applied N. Loss was smallest at Aguilar where wind speeds were low and the greatest at Mabitac where floodwater pH values and temperatures were high and the winds were strong. The ammonia loss was reduced at all sites by incorporating the urea into the soil by harrowing. However, the reduction achieved varied markedly between sites, with the largest reduction (from 56% to 7% loss of the applied N) being observed at Mabitac. The total N lost from the basal application into the floodwater ranged from 59% to 71% of the applied N. Incorporating the urea by harrowing reduced the total N loss at two sites, increased the total N loss at the third site, and had no effect at the fourth site. The denitrification losses ranged widely (from 3% to 50% of the applied N) when urea was broadcast into the floodwater at the four sites. The denitrification loss was low when the ammonia loss was high (Mabitac) and high when the ammonia loss was low (Aguilar). Reducing ammonia losses by incorporating the urea into the flooded soil resulted in increased denitrification losses at three of the sites and appeared to have no effect on denitrification at the fourth site. The results show that reducing the ammonia loss by incorporating urea into the soil does not necessarily result in reduced total N loss, and suggest that the efficiency of fertilizer N will be improved only when both N-loss processes are controlled simultaneously.  相似文献   

10.
Abstract

Absorption of volatilized ammonia after application of slurry onto the soil surface (sand) between rows of a wheat crop was studied in two experiments. The slurry was labelled with 15N-NH4. During seven days the accumulated gaseous N loss from the slurry varied from 6.9 to 11.1 g N m?2. In April ammonia losses from slurry applied beneath a 5 cm high wheat crop were equal to losses from slurry applied to a fallow, but 2.2% of the lost atmospheric ammonia was taken up by the leaves. In May ammonia loss from slurry applied between the rows of a 43 cm high crop was reduced by 6% compared to the loss from fallow, because of a reduced transfer of ammonia from the slurry to the air. Of the emitted ammonia 3.3% was absorbed by the canopy.  相似文献   

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