长期施用有机肥小麦玉米轮作土壤系统氮盈余及损失量估算

以连续10年长期定位试验数据为依据,研究不同有机肥(以纯N计)0、120、240、360、600 kg/hm2处理在冬小麦-夏玉米轮作土壤系统的氮素吸收利用和土壤氮库变化,利用氮素平衡法估算氮损失量,计算氮素利用率、残留率和损失率,探讨利用氮素平衡法计算氮效率作为有机肥合理施用的评价指标.结果表明:(1)随着试验年限的...     

氮水平对水稻植株氮素损失的影响

利用15N差值法,在溶液培养条件下研究了不同氮肥水平对水稻植株氮损失的影响,并就影响水稻氮损失的因素进行了分析。结果表明,对前期正常供氮的水稻幼苗做为期10 d的不同氮(N 04、0、801、60 mg/L)处理,水稻植株生物量未受显著影响,表明前期吸收氮可维持水稻生长。但是,随着供氮水平的提高,叶片及根的含氮量显著增加,而15N的丰度却显著下降,叶片15N的丰度显著高于根。说明高氮处理增加了水稻植株吸氮量并稀释了前期吸收的15N,而且根系累积的氮向地上部转移。缺氮(N 0 mg/L)与过量供氮(N 160 mg/L)均显著增加植株氮的损失率,而适量供氮(N 80 mg/L)则氮肥利用率显著提高。水稻的生长期显著影响植物氮的损失率,在N 80 mg/L的条件下,随着水稻生长期的延长,植株氮损失从11.6%增加到22.3%。同时,随着供氮水平的增加,叶片中NH4+-N含量和谷草转氨酶(GOT)活性均显著增加,叶片组织pH也随之增加。表明植物体内铵浓度增加而引起的氨挥发是导致植物氮损失增加的原因之一。     

鸡内源氮损失量与内源能排出量相关性分析

用 3 2只 40 0日龄海兰褐父母代种公鸡来研究鸡内源排泄物中内源氮损失量与内源能排出量的相关性。结果为 :鸡内源氮损失量和内源能排出量之间呈现出强相关关系 ,相关系数r=0 .97(P <0 .0 1) ,二者的直线回归方程为 :Y =2 1.0 2 + 3 6.2 1x ,回归系数b =3 6.2 1KJ/ g。表明内源排泄物中代谢粪氮的能值与尿的能值不同 ,粪中氮的能值高于尿中氮的能值。用内源排泄物中氮的能值代替尿的能值进行代谢能的校正更为合理     

针叶林施肥及减少氮损失的途径

<正> 在近15—20年不同组成和树龄级的林内施用无机肥的实践证明,通过施肥,首先是氮肥,是能够提高林地生产力的。如在白俄罗斯的近熟和成熟的针叶林内,每公顷施氮肥150—200公斤,年生长量提高15—30%,5—6年,每公顷可增长干材15—20m~3。但是,氮肥的利用率不高,仅占50—70%。肥效不高的主要原因是施肥方法、时间和施肥量不当,忽视了复杂的农业气象条件。因     

马唐牧草红壤氮肥的氨挥发、径流和淋溶损失

探讨了我国南方红壤上种植牧草马唐施不同量氮肥,施氮量与土壤氨挥发、径流和1 m深土壤淋溶损失氮量的关系。结果表明,在施用N 90、160、230 kg hm-2尿素处理下,土壤氨挥发损失量分别为N0.67、1.24和5.16 kg hm-2,分别占施氮量的0.74%0、.77%和2.24%,土壤氨挥发损失量(y)与施氮量(x)呈指数递增关系:y=0.156 3e0.014 6x;径流氮素损失量分别为N 1.05、0.88和1.01 kg hm-2,分别占施氮量的1.17%、0.55%和0.44%,径流损失的氮量与施氮量之间无明显相关性;淋溶损失总氮量为2.05、2.86和4.09kg hm-2,分别占施氮量的0.91%、1.02%和1.24%,土壤淋溶损失总氮量(y)与施氮量(x)呈线性递增关系:y=0.012 2x 1.087 7。     

无定形锰氧化物在氮素损失中的作用

Studies have been made,by ^15N-tracer technique on nitrogen loss resulting from adding amorphous manganese oxide to NH4^ -N medium under anaerobic conditions.The fact that the total nitrogen recovery was decreased and that ^15NO2,^15N2O,^15N^14NO,^15NO,^15N2 and ^15N^14N were emitted has proved that,like amorphous iron oxide,amorphous manganese oxide can also act as an electron acceptor in the oxidation of NH4^ -N under anaerobic conditions and give rise to nitrogen loss.This once again illustrates another mechanism by which the loss of ammonium nitrogen in paddy soils is brought about by amorphous iron and manganese oxides.The quantity of nitrogen loss by amorphous manganese oxide increased with an increase in the amount of amorphous manganese oxide added and lessened with time of its aging.The nitrogen loss resulting from amorphous manganese oxide was less than that from amorphous iron oxide.And the nitrogen loss resulting from amorphous manganese oxide was less than that from amorphous iron oxide.And the nitrogen loss by cooperation of amorphous manganese oxide and microorganisms (soil suspension) was larger than that by amorphous manganese oxide alone.In the system,nitrogen loss was associated with the specific surface ares and oxidation-reduction of amorphous manganese oxide.However,their quantitative relationship and the exact reaction processes of nitrogen loss induced by amorphous manganese oxide remain to be further studied.     

红壤地油菜上施用的尿素态氮的去向及尿素在提高油菜产量中的效率

Fate of urea nitrogen(N) applied to rape grown on a red soil was investigated by the 15N mass balance technique.and efficiency of urea and effect of nutrients balance in raising rape yield were investigated in a field plot experiment.One hundred and thirty -eight kg N/ha,86kg N/ha as basal dressing and 52 kg N/ha as top dressing,was applied with band application technique.The experiment was conducted in the southeast of china ,near Yingtan City,Jianxi Province.Results from 15N mass balance study showed that when urea urea was applied as basal dressing the plant recovery was 44.0% of the applied N for Treatment T (with application of N,P,K,B and lime),Plant recoveries were 38.0%-40.5% for Treatments-K,-B-lime and RS(without application of K,B or lime as well as with additional rice straw compared with Teatment T),which were not significantly different from Treatment T.In contrast ,plant recovery was only 5.1% for Treatment-P(without application of P), indicating that P was the factor limiting N uptake by rape.However,N remaining in 0-0.30 m soil was high up to 71.6% for Treatment-P,while the corresponding data were 33.0%-42.6% for the other treatments.The total recovery of applied N(including plant recovery and N remaining in 0-0.60 m soil) was 91.5% for Treatment T when urea was applied as basal dressing,while almost all the applied N was recovered when ureawas applied as top drssing,It was suggested that N loss was greatly controlled by using band application method in this experiment.Results from the field plot experiment field plot experiment showed that N supply capacity of this red soil was very low,and the efficiency of the applied N was quite high,7.1kg rape seed was increased by application of one kg N for Treatment T.Nitrogen and phosphorus were the key factors limiting rape yield,and the yield was very low when neither of them was applied.The yield in Treatment-K was significantly lower than that in Treatment T,With the former accounting for 77% of the later.     

黄泛区潮土-冬小麦系统中尿素的转化和化肥氮去向

在田间条件下,用~(15)N标记的微区试验法研究了潮土-冬小麦系统中尿素的转化和化肥氮的去向。结果表明:土壤中尿素水解后,主要进行硝化和生物固定,而被粘土矿物固定的量很少;小麦返青后,随着气温上升,生物固定的标记氮不断分解,其量可达总生物固定量的60％。作为基肥条施的尿素,其损失略高于作返青肥或拔节肥表施后随即灌水的处理。氮素损失主要发生在春季气温回升后的生长期间,当季的淋洗损失极微。在较为适宜的用量和施用技术下,化肥氮的损失仍达33—45％,其中以碳酸氢铵为最高,次为硫酸铵和硝酸铵,而尿素和硝酸铵中的硝态氮损失最低。     

Ammonia Volatilization from Urea Applied to Acid Paddy Soil in Southern China and Its Control

Results showed that ammonia loss from urea broadcast into floodwater and incorporated into soil at transplanting was as high as 40% of applied N,and the corresponding total nitrogen (N) loss was 56%.Ammonia loss was measured with simplified micrometeorological method (ammonia sampler),and total N loss was concurrently measured using ^15N balance technique.The experiment was conducted under strong sunshine conditions on acid paddy soil derived from Quaternary red clay.The ammonia loss in this particular condition was much greater than those obtained from previous studies when urea was also applied to acid paddy soil but under cloudy conditions.It is concluded that the strong sunshine conditions with high temperature and shallow floodwater during the period of present experiment favoured ammonia volatilization.Application of stearyl alcohol on the surface of the floodwater reduced ammonia loss to 23% of applied N.However,the effect of stearyl alcohol was short-lived,probably due to the microbiological decomposition.     

江苏句容水库农业流域农田土壤反硝化作用的研究

2008年6月、8月、12月和2009年3月,在江苏句容水库农业流域采集农田原状土壤样品,使用乙炔抑制实验室培养法测定土壤的反硝化速率,同时测定土壤的含水率、铵态氮(NH4+-N)和硝态氮(NO3--N)的含量,研究农田土壤反硝化速率变化、影响因素及其对流域氮损失的贡献。结果显示,旱地土壤反硝化速率范围在0.13～51.96kgN.hm-.2a-1之间,水田土壤的反硝化速率范围在3.16～12.29kgN.hm-.2a-1之间。相关分析表明,反硝化速率与土壤硝态氮(NO3--N)浓度、铵态氮(NH4+-N)浓度之间不具有显著相关关系;在12月和3月,反硝化速率与土壤含水率之间有显著相关关系,其他月份无显著相关关系。流域内农田土壤反硝化损失的总氮量为31.93tN.a-1,低于流域施氮总量的3.19%,可见,反硝化作用不是该流域氮损失的主要途径。