钾肥对灌浆期冬小麦群体内叶片光合特性的影响

通过在连续6年施钾与不施钾处理的试验区内,对冬小麦(Triticum aestivum)灌浆期群体内旗叶叶片光合特性的研究表明,施用钾肥时,最大净光合速率(Pmax)增加,光饱和点(LSP)和光补偿点(LCP)提高,表观量子效率(α)降低,表观暗呼吸速率(Rd)略有上升;施钾与不施钾处理的净光合速率(Pn)日变化,晴天和阴天均呈单峰曲线,晴天午前与午后及阴天各时刻的瞬间净光合速率(Pn)下降的主要原因是“气孔因素”,而晴天中午前后则更主要是由于“非气孔因素”作用.     

CO2浓度、氮和水分对春小麦光合、蒸散及水分利用效率的影响

研究了不同土壤氮和土壤水分条件下,大气CO2浓度升高对春小麦光合作用、气孔导度、蒸散和水分利用效率的影响。结果表明,CO2浓度升高,干旱处理的春小麦（Triticum aestivum L.）叶片光合作用速率幅度增加大于湿润处理,随着氮肥用量增加光合速率相应增加,而不施氮脂增加有限;干旱处理气孔导度幅度减少大于湿润处理,不施氮肥的大于氮肥充足的CO2浓度升高,干旱处理的蒸散量减少比湿润处理多,不施氮肥的蒸散量减少较为明显;但干旱处理单叶WUE增加大于湿润处理;随着氮肥用量增加,冠层WUE提高,而不施氮肥的冠层WUE最低。因而CO2浓度升高、光合速率增加和蒸散量减少会减缓干旱的不利影响,增强作物对干旱胁迫的抵御能力。     

施钾对花生养分吸收、产量与效益的影响

对江淮丘陵地区花生钾素的养分吸收特点以及施钾对花生产量和经济效益的影响进行了研究。结果表明,在一定氮、磷肥供给水平上,增施钾肥,能调节植株体内养分的运输与分配,促进植株对N、P、K养分的吸收,显著提高花生生殖器官的干物质积累,从而有利于提高花生的产量、品质和抗性,每生产100kg荚果,对N、P、K养分吸收量分别为3．08～5．35、0．6～1．2、3．45～6．66kg。其中对K的吸收量最大。主要集中在营养器官中;N、P的吸收主要集中在荚果等生殖器官中,随着施K量的增加,各器官中N、P、K含量均随之增加,但K的增加最多,P增加最少,当施K量为150～180kg·hm^-2,且N、P、K的施肥配比为2：1：2时,花生荚果的产量最高(5425．5kg·hm^-2),经济效益最大(13878．7元·hm^-2),产投比达到6．75：1,增产增收效果显著;而施K量超过225kg·hm^-2时,花生产量和效益明显下降,因此,在花生生产上可以推荐N150P75K150作为该地区高产栽培的平衡施肥配方。     

水肥异区交替灌溉对夏玉米生理指标的影响

以夏玉米品种‘户单4号'为材料,通过防雨棚内微区试验研究了两种灌水量(450 m~3/hm~2和900 m~3/hm~2)条件下水肥异区交替灌溉和均匀灌溉对夏玉米生长以及某些生理指标的影响.结果显示:(1)在节水50%的条件下,水肥异区交替灌溉与高灌水量均匀灌溉的夏玉米生物量、产量均无显著差异.(2)低灌水量时,水肥异区交替灌溉下的玉米根系伤流液、叶片可溶性蛋白含量、硝酸还原酶活性、光合速率、蒸腾速率等均高于均匀灌溉施肥处理,而植株全氮含量及叶片水分利用效率与均匀灌溉施肥的差异不显著.(3)高灌水量时,水肥异区交替灌溉处理除根系活力、光合速率以及蒸腾速率高于均匀灌溉处理外,其他指标均低于后者.研究表明,在低灌水量条件下,水肥异区交替灌溉能使夏玉米保持较高的根系活力和正常生理代谢,提高其叶片水分利用效率,从而达到了节水增产的目的.     

伴矿景天-水稻轮作及磷修复剂对水稻锌镉吸收的影响

采用盆栽试验,将锌镉超积累植物伴矿景天与镉低积累水稻中香1号轮作种植于重金属污染土壤,并向土壤添加钙镁磷肥和磷矿粉,研究两种磷修复剂对伴矿景天和镉低积累水稻生长及地上部重金属积累性的影响.盆栽试验结果表明,在轻污染土壤上施用50 g·kg^-1磷矿粉时伴矿景天地上部的Zn、Cd吸收量分别达到每盆11.5 和0.79 mg,效果好于施用4 g·kg^-1钙镁磷肥处理.在重金属污染土壤上种植伴矿景天使后茬水稻地上部Zn、Cd浓度上升,但钙镁磷肥的施用显著降低了水稻体内的Zn、Cd积累量.种植伴矿景天后添加钙镁磷肥稳定调控剂对土壤中水溶态及NH₄OAc提取态Zn、Cd的稳定效果明显优于磷矿粉,且在高污染土壤上效果更佳.田间试验结果显示,施用钙镁磷肥不仅可增加水稻产量,且可一定程度上降低水稻地上部的Zn、Cd吸收量.     

Potential of vetiver (vetiveria zizanioides (L.) Nash) for phytoremediation of petroleum hydrocarbon-contaminated soils in Venezuela

Venezuela is one of the largest oil producers in the world. For the rehabilitation of oil-contaminated sites, phytoremediation represents a promising technology whereby plants are used to enhance biodegradation processes in soil. A greenhouse study was conducted to determine the tolerance of vetiver (Vetiveria zizanioides (L.) Nash) to a Venezuelan heavy crude oil in soil. Additionally, the plant's potential for stimulating the biodegradation processes of petroleum hydrocarbons was tested under the application of two fertilizer levels. In the presence of contaminants, biomass and plant height were significantly reduced. As for fertilization, the lower fertilizer level led to higher biomass production. The specific root surface area was reduced under the effects of petroleum. However, vetiver was found to tolerate crude-oil contamination in a concentration of 5% (w/w). Concerning total oil and grease content in soil, no significant decrease under the influence of vetiver was detected when compared to the unplanted control. Thus, there was no evidence of vetiver enhancing the biodegradation of crude oil in soil under the conditions of this trial. However, uses of vetiver grass in relation to petroleum-contaminated soils are promising for amelioration of slightly polluted sites, to allow other species to get established and for erosion control.     

不同栽培措施对降香黄檀内源激素含量的影响

为了了解不同栽培措施对降香黄檀叶片内源激素的影响,本研究通过铺设修枝、移植、钾肥、乙烯4个试验,分析各处理叶片激素含量特征。结果表明：修枝实验中,重度修枝处理IAA、GA₃、ZR、ABA含量均最大,分别为69.849、6.619、8.805、77.998 ng·g^-1。移植各处理中,去冠移处理IAA、ZR含量最高分别为73.195和9.472 ng·g^-1,而其ABA含量最低为52.001 ng·g^-1,GA₃含量最高的为断根处理8.418 ng·g^-1。IAA、ZR、GA₃含量K1钾肥配比最高分别为75.188、8.383、6.127 ng·g^-1;ABA最大含量71.082 ng·g^-1为CK处理。乙烯试验中,CK处理的IAA、GA₃含量最高分别为47.762、4.967 ng·g^-1;E2.5%处理的ABA含量96.94 ng·g^-1最高。E0.1%处理的ZR含量最高为9.378 ng·g^-1。修枝对GA₃/ABA和ZR/GA₃影响较大,其最小值分别比最大值降低了29.7%、19.0%。移植对IAA/ABA、GA₃/ABA影响较大,最小值比最大值依次降低了52.47%和51.47%。树干注射乙烯和钾肥对IAA/ABA、GA₃/ABA影响较大,乙烯试验最小值分别比最大值降低了55.4%、49.2%,钾肥试验最小值分别比最大值降低了48.8%和37.1%。     

Nutrient availability and leaching in an archaeological Anthrosol and a Ferralsol of the Central Amazon basin: fertilizer,manure and charcoal amendments

Soil fertility and leaching losses of nutrients were compared between a Fimic Anthrosol and a Xanthic Ferralsol from Central Amazônia. The Anthrosol was a relict soil from pre-Columbian settlements with high organic C containing large proportions of black carbon. It was further tested whether charcoal additions among other organic and inorganic applications could produce similarly fertile soils as these archaeological Anthrosols. In the first experiment, cowpea (Vigna unguiculata (L.) Walp.) was planted in pots, while in the second experiment lysimeters were used to quantify water and nutrient leaching from soil cropped to rice (Oryza sativa L.). The Anthrosol showed significantly higher P, Ca, Mn, and Zn availability than the Ferralsol increasing biomass production of both cowpea and rice by 38–45% without fertilization (P<0.05). The soil N contents were also higher in the Anthrosol but the wide C-to-N ratios due to high soil C contents led to immobilization of N. Despite the generally high nutrient availability, nutrient leaching was minimal in the Anthrosol, providing an explanation for their sustainable fertility. However, when inorganic nutrients were applied to the Anthrosol, nutrient leaching exceeded the one found in the fertilized Ferralsol. Charcoal additions significantly increased plant growth and nutrition. While N availability in the Ferralsol decreased similar to the Anthrosol, uptake of P, K, Ca, Zn, and Cu by the plants increased with higher charcoal additions. Leaching of applied fertilizer N was significantly reduced by charcoal, and Ca and Mg leaching was delayed. In both the Ferralsol with added charcoal and the Anthrosol, nutrient availability was elevated with the exception of N while nutrient leaching was comparatively low.     

基施氮肥对冬小麦产量、氮肥利用率及氮平衡的影响

通过田间小区试验研究了氮肥一次基施对高肥力土壤上冬小麦产量,吸氮量及氮肥利用率的影响,旨在了解高肥力土训上减少基肥氮的可行性,结果表明,高肥力土壤上冬小麦产量对氮肥的反应不明显,而施用氮肥显著增加了冬小麦吸氮量,根据差值法计算结果,当施氮量为75,112．5和150kg/hm^2时冬小麦的氮肥利用率分别为16．0％,14．5％和13．5％,表明多达84％－86．5％以上的基肥氮未被作物吸收利用,氮平衡计算的结果进一步表明,未被当季小麦利用的肥料氮主要以无机氮的形式残留于0－1m土体中,当施氮量分别为75,112．5和150kg/hm2时氮肥的土壤残留率依次为83．3％,46．0％和58．8％,而相应的表观损失率为0．5％,38．9％和19．0％,由此可见,在高肥力土壤上应严格控制基肥氮的用量或不施基肥,否则将造成氮素资源的大量浪费。     

The fate of residual 15N-labelled fertilizer in arable soils: its availability to subsequent crops and retention in soil

An earlier paper (Macdonald et al., 1997; J. Agric. Sci. (Cambridge) 129, 125) presented data from a series of field experiments in which ¹⁵N-labelled fertilizers were applied in spring to winter wheat, winter oilseed rape, potatoes, sugar beet and spring beans grown on four different soils in SE England. Part of this N was retained in the soil and some remained in crop residues on the soil surface when the crop was harvested. In all cases the majority of this labelled N remained in organic form. In the present paper we describe experiments designed to follow the fate of this `residual' <sup>15</sup>N over the next 2 years (termed the first and second residual years) and measure its value to subsequent cereal crops. Averaging over all of the initial crops and soils, 6.3% of this `residual' ¹⁵N was taken up during the first residual year when the following crop was winter wheat and significantly less (5.5%) if it was spring barley. In the second year after the original application, a further 2.1% was recovered, this time by winter barley. Labelled N remaining after potatoes and sugar beet was more available to the first residual crop than that remaining after oilseed rape or winter wheat. By the second residual year, this difference had almost disappeared. The availability to subsequent crops of the labelled N remaining in or on the soil at harvest of the application year decreased in the order: silty clay loam>sandy loam>chalky loam>heavy clay. In most cases, only a small proportion of the residual fertilizer N available for plant uptake was recovered by the subsequent crop, indicating poor synchrony between the mineralization of ¹⁵N-labelled organic residues and crop N uptake. Averaging over all soils and crops, 22% of the labelled N applied as fertilizer was lost (i.e., unaccounted for in harvested crop and soil to a depth of 100 cm) by harvest in the year of application, rising to 34% at harvest of the first residual year and to 35% in the second residual year. In the first residual year, losses of labelled N were much greater after spring beans than after any of the other crops.