营养和病虫害管理对双季杂交水稻种植系统的土壤生态质量的共同影响

The mineral fertilizers(NPK) and pesticide,including herbicides,insecticides and fungicides,were applied alone or in combination and the soil sampling was done at different growth stages during the crop cycle to study the changes in soil organic matter,microbial biomass and their activity parameters in a paddy soil with different nutrient and pest management practices in a hybrid rice double-cropping system.A consistent increase in the electron transport system(ETS) activity was measured during the different crop growth stages of rice.The use of fertilizers(NPK) alone or with pesticides increased ETS activity,while a decline of ETS activity was noticed with pesticides alone as compared with the control.Nearly an increasing trend in soil phenol content was observed with the progression of crop growthstages,while the usage of pesticides alone caused maximum increments in the soil phenol content.The soil protein content was found nearly stable with fertilizers and/or pesticides application at various growth stages in both crops taken.But notable changes were noticed at different growth stages probable because of fluctuations in moisture and temperature at particular stages,which might have their effects on N mineralization.Marked depletions in the phospholipid content were found with the advancement of crop growth stages,while the incorporation of fertilizers and/or pesticides also produced slight changes,in which a higher decline was noticed with pesticide application alone compared with the control.     

氮施用水平和方式对高粱作物产量和质量的影响

A field study was conducted for two years at the Arid Zone Research Institute, Dera Ismail Khan, Pakistan, to determine the optimum level of nitrogen and efficient application method in the production of sorghum （Sorghum bicolor L.）. Using four levels of nitrogen, i.e., 0, 60, 90, and 120 kg ha^-1, and two different application methods （soil application and foliar spray）, the experiment was laid out in a split-plot design, where the main plots were used to determine the effective method of application and the subplots were used to detect the influence of N levels on the grain yield. The average data obtained after two years of study indicated an increase in the grain yields with an increase in N levels irrespective of the method used of N application. The grain yield increased from 2.92 to 5.61 t ha^-1 in the plots that were treated with 90 kg N ha^-1 compared with the control plots. Quadratic regression analysis showed that the increase in the yield was higher at the lower levels of N compared with the succeeding higher levels. The soil application method, producing an average grain yield of 4.79 t ha^-1, was found to be superior to the foliar spray method with an average grain yield of 4.56 t ha^-1. The protein content of the grain showed a linear increase with N application, attaining the maximum at 120 kg N ha^-1 in both the methods of N application. In addition, compared with the method of soil application, higher crude protein contents were observed using the method of foliar spray at all N levels.     

番茄不同生育期遮荫对其干物质分布、产量及叶片养分含量的影响

Pot-grown tomato plants (Lycopersicon esculentum Mill. cv. Maofen) was used to study the effects of three shading levels (0, 75% and 40%) for 8 days on dry matter partitioning, contents of nitrogen (N),phosphorus (P) and potassium (K) in leaves and yield at three growth stages (early flowering (EF), peak flowering (PF) and later flowering (LF)). Shading reduced the dry weight of root and stem tissues at the EF and PF stages, but the 40% shading increased root dry weight and stem dry weight by 43.2% and 21.6%,respectively, at the LF stage. The influence of shading on the dry weight of leaves was very small at most growth stages. Shading had no effects on total leaf N, P and K contents at the EF and PF stages, showing that N, P and K absorption were regulated by the carbon assimilation at these two stages. The leaf N, Pand K contents of 40% shaded plants at the LF stage were significantly increased. There were no obvious differences in leaf N and K contents between 75% and 40% shading treatments, but significant difference in leaf P contents was found between them at the LF stage. Shading significantly enhanced the friit yield of 40% shaded tomato plants at the LF stage, but failed to affect the fruit yield of shaded plants at the EF stage. These showed that tomato could grow well and a better yield could be obtained if some moderate shading (i.e., 40% shading) was applied at the LF stage at s, mmer midday.     

Effects of Irrigation Patterns and Nitrogen Fertilization on Rice Yield and Microbial Community Structure in Paddy Soil

Water and nitrogen (N) are considered the most important factors affecting rice production and play vital roles in regulating soil microbial biomass, activity, and community. The effects of irrigation patterns and N fertilizer levels on the soil microbial community structure and yield of paddy rice were investigated in a pot experiment. The experiment was designed with four N levels of 0 (N0), 126 (N1), 157.5 (N2), and 210 kg N ha-1 (N3) under two irrigation patterns of continuous water-logging irrigation (WLI) and water-controlled irrigation (WCI). Phospholipid fatty acid (PLFA) analysis was conducted to track the dynamics of soil microbial communities at tillering, grain-filling, and maturity stages. The results showed that the maximums of grain yield, above-ground biomass, and total N uptake were all obtained in the N2 treatment under WCI. Similar variations in total PLFAs, as well as bacterial and fungal PLFAs, were found, with an increase from the tillering to the grain-filling stage and a decrease at the maturity stage except for actinomycetic PLFAs, which decreased continuously from the tillering to the maturity stage. A shift in composition of the microbial community at different stages of the plant growth was indicated by principal component analysis (PCA), in which the samples at the vegetative stage (tillering stage) were separated from those at the reproductive stage (grain-filling and maturity stages). Soil microbial biomass, measured as total PLFAs, was significantly higher under WCI than that under WLI mainly at the grain-filling stage, whereas the fungal PLFAs detected under WCI were significantly higher than those under WLI at the tillering, grain-filling, and maturity stages. The application of N fertilizer also significantly increased soil microbial biomass and the main microbial groups both under WLI and WCI conditions. The proper combination of irrigation management and N fertilizer level in this study was the N2 (157.5 kg N ha-1) treatment under the water-controlled irrigation pattern.     

华北地区采用无机氮测试和植株速测进行夏玉米氮肥推荐

A field experiment with a split-plot design was carried out at Dongbeiwang Farm in Beijing Municipality to establish reliable N fertilizer recommendation indices for summer maize (Zea mays L.) in northern China using the soil Nmin(mineral N) test as well as the plant nitrate and SPAD (portable chlorophyll meter readings) tests. The results showed that Nrnin sollwert (NS) 60 kg N ha^-1 at the third leaf stage and N rate of 40 to 120 kg N ha^-1 at the tenth leaf stage could meet the N requirement of summer maize with a target yield of 5.5-6 t ha^-1. Sap nitrate concentrations and SPAD chlorophyll meter readings in the latest expanded maize leaves at the tenth leaf stage were positively correlated with NS levels, indicating that plant nitrate and SPAD tests reflected the N nutritional status of maize well. Considering that winter wheat subsequently utilized N after the summer maize harvest, the 0-90 cm soil Nmin (74 kg N ha^-1) and apparent N loss (12 kg N ha^-1) in the NS60＋40 treatment were controlled at environmentally acceptable levels. Therefore NS60＋40, giving a total N supply of 100 kg N ha^-1, was considered the optimal N fertilizer input for summer maize under these experimental conditions.     

长期定位试验尿素和堆肥处理下冬小麦自然同位素15N研究

We investigated 15N abundance （δ15N） of winter wheat （Triticum aestivum cv. Jinmai 1） plants and soil at different growth stages in a field with a 13-year fertilization history of urea and compost, to determine whether or not the δ15N of plant parts can be used as an indicator of organic amendment with compost. Plant parts （roots, leaves, stems and grains） and soil were sampled at re-greening, jointing, grain filling and mature growth stages of winter wheat. There were significant differences between the urea and compost treatments in 815N of whole plants, plant parts and soil over the whole growing season. Determination of the δ15N of plant parts was more convenient than that of whole plant to distinguish between the application of organic amendment and synthetic N fertilizer.     

树木年轮中养分元素含量的角分布及其环境信息

The effects of nitrogen,phosphorus and potassium application level,seed rate and transplanting density on the growth and development of rice plants were studied to find out nutrient status in high-yielding rice plants and to increase grain yield by adequate fertilization.There was an equilibrium relationship among nutrient elements for high-yielding rice plant populations.The equilibrium index of nutrient amount ,content and distribution in high-yielding rice plants should be generally greater than-2 but less than 2.The optimum nutritive proportion of nitrogen:phosphorus:potassium assimilated by the plants was about 10:2:9 at the ripening stage.But the content and the proportion varied with the growth stages,Therefore,the nutrient in rice plant populations should be in a dynamic equilibrium.So as to achieve high yield.     

氮肥对草莓根系生长发育和内源激素影响的研究

Endogenous hormones play an important role in the growth and development of roots. The objective of this research was to study the effect of four types of N fertilizer on the root growth of strawberry (Fragaria ananassa Duchesne) and the endogenous enzymes of indole-3-acetic acid (IAA), abscisic acid (ABA), and isopentenyl adenosine (iPA) in its roots and leaves using enzyme-linked immunosorbent assay. Application of all types of N fertilizers at 20 d after transplanting significantly depressed (P ≤ 0.05) root growth. Application of organic-inorganic fertilizer (OIF) as basal fertilizer had a significant negative effect (P ≤ 0.05) on root growth. The application of OIF and urea at 60 d lowered the lateral root frequency in strawberry plants (P ≤ 0.05) compared with the application of two organic fertilizers (OFA and OFB) and the control (CK). With the fertilizer treatments, there were the same concentrations of IAA and ABA in both roots and leaves at the initial growth stage (20 d), lower levels of IAA and ABA at the later stage (60 d), and higher iPA levels at all seedling stages as compared to those of CK. Thus, changes in the concentrations of endogenous phytohormones in strawberry plants could be responsible for the morphological changes of roots due to fertilization.     

养分与田间管理对杂交稻种植体系中土壤微生物群落底物利用模式的联合效应

A field experiment was conducted to study the combined effect of nutrient and pest managements on soil biomass phospholipid contents,functional biodiversity and substrate utilization patterns of soil microbial populations in hybrid rice cropping system. The mineral N,P and K fertilizers (as urea,calcium superphosphate and KCl respectively) were incorporated at 100,25,and 100 kg ha^-1,respectively, and the various pesticides were applied at the recommented rates. The results of the experiment demonstrated a decline in the microbial abundance and soil microbial biomass phospholipid contents with the advancement of crop growth, and significant changes in substrate utilization pattern of soil microbial population studied were observed with different management practices and at different growth stages. The principal component analysis (PCA) using all 95-carbon sources (BIOLOG plates) gave good differentiation among the treatments, indicating that they have different patterns of carbon utilization under different habitats. The data showed that diversity in microbial community continuously changed with the progression in crop stage,particularly at physiological maturity (PM) stage that was evident from the utilization of different carbon sources at various crop stages.     

菜地土壤中氮肥的反硝化损失和N2O排放

A field experiment was conducted on Chinese cabbage （Brassica campestris L. ssp. pekinensis （Lour.） Olsson） in a Nanjing suburb in 2003. The experiment included 4 treatments in a randomized complete block design with 3 replicates： zero chemical fertilizer N （CK）; urea at rates of 300 kg N ha^-1 （U300） and 600 kg N ha^-1 （U600）, both as basal and two topdressings; and polymer-coated urea at a rate of 180 kg N ha^-1 （PCU180） as a basal application. The acetylene inhibition technique was used to measure denitrification （N2 ＋ N2O） from intact soil cores and N2O emissions in the absence of acetylene. Results showed that compared to （3K total denitrification losses were significantly greater （P ≤ 0.05） in the PCU180, U300, and U600 treatments,while N2O emissions in the U300 and U600 treatments were significantly higher （P ≤ 0.05） than （3K. In the U300 and U600 treatments peaks of denitrification and N2O emission were usually observed after N application. In the polymer-coated urea treatment （PCU180） during the period 20 to 40 days after transplanting, higher denitrification rates and N2O fluxes occurred. Compared with urea, polymer-coated urea did not show any effect on reducing denitrification losses and N2O emissions in terms of percentage of applied N. As temperature gradually decreased from transplanting to harvest, denitrification rates and N2O emissions tended to decrease. A significant （P ≤0.01） positive correlation occurred between denitrification （r = 0.872） or N2O emission （r = 0.781） flux densities and soil temperature in the CK treatment with a stable nitrate content during the whole growing season.     

烤烟烟碱合成及其氮素来源与移栽期和氮肥的关系研究

采用田间试验与15N同位素示踪微区试验,在湖北襄樊植烟生态区老湾村(N 31°27,′E 111°14′,海拔1130 m)研究了3个不同移栽期和施用氮肥对烤烟烟碱含量和烟碱氮素来源的影响。研究结果表明,与5月5日移栽相比,推迟移栽期至5月15日2~5日,烟碱含量、烟碱氮占总氮比例以及烟碱肥料氮比例分别平均增加10%8~5%、5%1~10%和21%5~6%;与不施氮相比,施用氮肥提高烟碱含量12%5~9%,提高烟碱氮占总氮比例5%~127%。烤烟烟碱氮占总氮的比例随生育进程逐渐增加,而各部位烟叶烟碱肥料氮比例随生育进程和叶位上升逐渐下降。土壤氮是烟碱氮的主要来源,对烟叶烟碱含量有决定性影响。结果说明在当地条件下,控施氮肥和适当提前移栽期更有利于降低烟叶(尤其是中、上部叶)中的烟碱含量。     

肥料~(15)N对烟叶氮和烟碱含量的影响

利用15N示踪技术在黄壤烟区研究了烤烟不同部位烟叶氮和烟碱含量的变化及肥料氮在烟碱中的分配。结果表明,不施氮肥的情况下,烟株第10片以上烟叶烟碱含量达到3.54%;施氮量为97.5kghm-2时,10片以上烟叶烟碱含量达到4.13%以上。烟碱积累在整个生育期是呈不断增加的趋势,于移栽后7周内积累较少,烟碱积累主要集中在9～15周,到烟叶采收结束17周为122.55kghm-2。烟叶进入成熟期后,烟碱含量与各部位烟叶来自土壤氮素比例呈正相关,其中与上部烟叶相关系数达0.88。烟碱总氮中来自肥料氮于下部、中部和上部烟叶分别占28.31%,26.63%和25.45%;相应构成烟碱的氮素中,下、中、上部烟叶中有来自土壤氮分别为71.69%、73.37%和74.55%。追肥氮占施氮总量30%条件下,烟碱中氮来自追肥氮在下、中和上部烟叶分别占14.25%、15.30%和14.94%,追肥氮是烟叶烟碱总氮主要氮源。     

我国烤烟生产中的氮素管理及其与烟叶品质的关系

在诸多营养元素中,氮素既是土壤中最不稳定的元素,也是影响烟叶产量和品质最为重要的元素。为追求产量,在我国目前的烤烟生产中氮肥施用过量的现象较为普遍。施氮量过高往往造成烟叶品质下降。生产中普遍推荐的肥料施用技术所提供的氮素与烟株生长的需氮规律不吻合。生长后期土壤氮素矿化使得烟株生长过程中的氮素营养难以控制,并缺乏有效的检测手段。目前对于造成烟叶中烟碱含量升高的真正原因没有正确认识。结合我们的研究,本文就我国烤烟生产中存在的上述问题进行分析与讨论。旨在通过努力达到烤烟生产中的氮素营养平衡,烟叶的化学成分趋于协调,并达到提高氮肥利用率、减少环境污染的目的。     

绿肥中养分释放规律及对烟叶品质的影响

在田间条件下利用埋设玻璃滤纸包法研究了绿肥翻压后的分解规律及其翻压绿肥对烟叶品质的影响。结果表明，经过13周的分解，苜蓿中有机C的矿化率高达81％，N素矿化率为54％；黑麦草有机C的矿化率为63％，N素矿化率为22％。这些矿化N中约92％的N（苜蓿）和74％的N（黑麦草）是在翻压后的前6周释放的。在烟株的整个生长期内，由苜蓿释放的N素约为N43奴hm^-2，为了防止后期N素供应过多而导致上部烟叶烟碱含量过高，苜蓿宜提前翻压并从总N肥施用量中扣除由苜蓿矿化出的N。黑麦草因N素含量低和N素矿化量少，整个生长季中约释放了N10．5kghm^-2的N素，所以在黑麦草生长量不大的情况下，可将黑麦草全部翻压并忽略其释放的N素。 在没有减少化肥施用量的情况下，翻压苜蓿提高了上部烟叶中烟碱含量，降低了总糖和还原糖含量。而翻压黑麦草对烟叶中烟碱含量有所降低，总糖和还原糖含量适中，因而烟叶的品质得到了改善。     

施氮量对植烟土壤不同土层无机氮质量含量的调控

为研究不同施氮量对土壤各层次和烤烟各生长期土壤中无机氮质量含量的影响,大田试验中设置5个氮肥施用量并分配在基肥、苗肥和追肥时期施用,烟苗移栽后第5周开始分7次钻取3个土层样,样品冷藏贮存并用流动注射分析仪测定硝态氮和铵态氮质量含量。结果表明：各施氮处理在移栽后第6周前0～20 cm土壤中硝态氮质量含量大于铵态氮,施用氮肥越多,土壤中无机氮质量含量提高幅度越大,施氮肥对0～20 cm土壤中无机氮质量含量的影响在烟株生育前期要远大于对20～40 cm土壤中无机氮质量含量的影响,同一时期不同深度比较,0～20 cm土层中硝态氮质量含量略大于20～40 cm和40～60 cm土层的硝态氮质量含量;烟株移栽7周后,0～20 cm土层中硝态氮被极大耗竭。各施氮量在各土层铵态氮质量含量变化幅度远大于硝态氮,铵态氮质量含量从第6周即开始上下波动,并在50 mg/kg附近上下变动,第8周土壤各层铵态氮质量含量有一个上升峰,而硝态氮质量含量在第7周停止快速下降后进入0～100 mg/kg范围的较平稳波动阶段。认为：不同施氮量对于生育前期和0～20 cm土层硝态氮质量含量影响深刻,但促进烤烟打顶前足量吸收并形成健壮烟株的合适施氮量还需结合烟草产量与品质而定;铵态氮调控是调节后期氮供应的关键。     

控制淋洗条件下土壤-花椰菜体系无机氮动态及平衡

在北京郊区中壤质潮土上设置田间试验。结果表明:花椰菜获最大产量的氮供应量为300kghm-2。生育期花椰菜主要吸收表层(0～30cm)土壤中的无机氮,对下层(30～60cm)土壤无机氮(Nmin)的利用随氮供应量的增加而减少。不同生育期0～60cm土层中无机氮(Nmin)含量均随氮供应量增加而增加,但施肥后土壤中最高无机氮(Nmin)含量出现的时间随氮供应量增加而延迟。花椰菜生育期土壤有机氮矿化速率随生长期延长而增加,平均达N1.3kghm-2d-1,相当于各处理总吸氮量的47.5%～89.2%。试验后0～30cm及30～60cm土层无机氮(Nmin)含量随氮供应量增加而明显增加,但60～90cm土层无机氮(Nmin)受氮供应的影响不明显。花椰菜当季氮肥利用率及氮素利用率随施氮量增加而降低,最佳产量时的氮肥利用率及氮素利用率分别为36.5%和50.8%。土壤-花椰菜体系氮素表观损失量随氮施用水平的增加而明显增加,但其占总氮供应(肥料氮+播前土壤氮)的比例受氮供应的影响不明显,大致为20%。     

不同来源氮素在烤烟体内的累积分配及对烟叶品质的影响

通过在云南省玉溪市赵桅村6组烟田（A）和赵桅实验基地（B）进行的大田15N示踪试验,研究了在不施氮和施氮90 kg/hm2条件下,水稻土烤烟干物质累积特征、肥料氮和土壤氮的吸收和分配及肥料氮和土壤氮对烟叶品质的影响。结果表明,施氮能显著提高烟株干物重,增加烟株吸氮量,但在生育后期施氮与不施氮处理,烟株均存在干物质和氮素累积过多问题。施氮90 kg/hm2情况下,烟株整个生育期中吸收的氮素主要来自于土壤氮,而且烟株吸收的土壤氮及其占总吸氮量的比例随生育期延长和烟叶着生部位的升高显著增加;到采收结束时,两试验田烟株吸收的土壤氮占总吸氮量的比例分别达69%和74%。不同施氮水平烟叶品质差异较大,不施氮处理各部位烟叶总氮和烟碱含量均偏低,糖碱比不协调;施氮处理各部位烟叶总氮含量均在适宜范围内,但由于烟株生育后期土壤供氮较多,上部烟叶存在烟碱含量偏高的问题。选择有机质含量适宜的土壤,控制烟株生育后期土壤供氮量,对降低上部烟叶总氮和烟碱含量,提高我国烟叶整体质量至关重要。     

添加外源碳调节植烟土壤氮素供应降低上部烟叶烟碱含量的研究

  【目的】  我国烤烟上部烟叶仍存在因烟碱含量较高而影响其品质的问题。向土壤中添加有效碳源可刺激微生物同化作用,进而能够调控土壤中有效氮含量。因此,本研究尝试利用外源碳降低烤烟上部叶全氮和烟碱含量。  【方法】  设置盆栽试验,烤烟品种为NC55,供试外源碳为葡萄糖 (G) 和木屑 (S)。试验设9个处理:在烤烟移栽后第90天,分别向植烟土壤中添加葡萄糖C 2000 mg/kg (G2)、5000 mg/kg (G5);在移栽后第90和120天依次添加葡萄糖C 2000 mg/kg和10000 mg/kg (G2+G10),和依次添加葡萄糖C 5000 mg/kg和10000 mg/kg (G5+G10);在移栽后第90天分别添加木屑C 2000 mg/kg (S2) 和5000 mg/kg (S5);在移栽后第90和120天依次添加木屑C 2000 mg/kg和葡萄糖C 10000 mg/kg (S2+G10),和依次添加木屑C 5000 mg/kg和葡萄糖C 10000 mg/kg处理 (S5+G10);对照 (CK)为常规施肥处理,在移栽后不添加外源碳。比较不同处理土壤氮素水平、烟叶全氮和烟碱含量。  【结果】  烤烟生长后期添加外源碳可明显降低植烟土壤氮素供应,降低幅度随外源碳添加量的增加而增大,添加二次比添加一次效果更明显,葡萄糖和木屑配合添加较单纯添加葡萄糖更有效。添加二次可降低上部叶的烟碱和全氮含量分别达0.62～1.40个百分点和0.71～1.22个百分点,比添加一次效果更为明显。  【结论】  烤烟生长后期在土壤中分别添加一定量的葡萄糖和木屑,能有效调节土壤碳氮比,抑制烤烟吸收过量的氮素,进而降低烤烟上部叶烟碱和全氮含量,提高烟叶品质。     

黑钙土氮素矿化与烤烟烟碱积累分配及品质的研究

于黑钙土上进行3个施氮量(0、52.5、67.5 kg·hm~(-2))试验,观察了土壤氮素矿化动态、烟碱积累与分配,以及烟叶的评吸质量.全生育期内,土壤氮素矿化量分别为93.53、65.54、51.66 kg·hm~(-2);烟碱积累总量分别为87.56、128.31、138.91 kg·hm~(-2);成熟采收时下部、中部和上部烟叶烟碱含量分别为1.56%～2.27%、2.01%～2.75%和2.45%～3.13%,烟叶烟碱含量随施氮量的增加而增加.黑钙土在不施氮肥的条件下,中下部烟叶烟碱含量较适中,烟叶品质相对较好,说明黑钙土本身有较强的供氮能力;生产中烤烟氮肥用量控制在52.5～67.5 kg·hm~(-2)为宜,可获得品质较好的烟叶.     

湘南典型植烟土壤养分供应及烟株吸收特征

养分是烤烟生长与烟叶品质形成的基础，为探究烤烟大田生育期间土壤养分供应、烟株养分吸收以及两者匹配情况及其与烟叶品质问题的关系，本研究测定和分析了湘南目前施肥模式下典型植烟土壤速效养分含量（铵态氮、硝态氮、有效磷和速效钾）、表观肥料养分利用率、烟株养分吸收以及有关烟叶品质指标，并监测了烤烟大田生育期间的气候条件及土壤温湿度变化状况。结果表明：①施氮总量较高(183 kg/hm2)，且基施氮量占比高(48.4%)，烤烟大田生育前期(0~36 d)土壤速效养分丰富，但烟株生长较慢，导致当季肥料养分利用率不高；②最后一次追肥时间(43 d)偏晚，使得后期烟株脱氮困难，造成顶叶和上二棚叶烟碱含量过高，还原糖含量偏低；③早春低温是烤烟大田生育前期烟株生长缓慢的重要影响因子。针对目前施肥模式与烟株养分需求不匹配问题及其主要影响因素，提出减施基肥、适时适量追肥的优化施肥模式以及应用控缓释肥料、促生微生物、高效多功能叶面肥和施加外源碳等对策。