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作物茎秆生物力学性质与形态特性相关性研究 总被引：9，自引：3，他引：9
为了应用生物力学性质指标对茎秆作物进行评价,进而指导作物优种筛选和选育,该文以北方优种选育的高粱、玉米、大豆、谷子等作物为研究对象,试验测试了作物的株高、节间距、含水率、茎秆干质量等形态特性指标,和茎秆各节间的弯曲强度、弹性模量、抗弯刚度、惯性矩等生物力学性质指标,并从宏观力学层面分析了生物力学性质指标沿高度的变化趋势,针对各生物力学性质指标及试验结果进行了力学机理分析,利用SAS分析软件对形态特性指标与生物力学性质指标进行了相关性分析.结果表明:不同作物形态指标与茎秆生物力学性质指标相关度不同,形态指标多数都与弯曲强度或弹性模量相关,并在此基础上确定了与力学指标相关度较大的形态特性指标.为应用生物力学方法评价作物抗倒伏及茎秆优势性状等优种特性奠定了基础. 相似文献
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不同产量水平下小麦倒伏与茎秆力学特性的关系 总被引：12，自引：2，他引：10
为探讨晋中晚熟冬麦区高产与倒伏的矛盾,研究小麦基部茎节形态结构与抗倒力学的关系,该文采用SAN-CMT6104微机控制电子万能材料测试仪,对大田不同产量水平及倒伏程度下的小麦基部第2茎节进行了弯折力、惯性矩、弹性模量、抗弯刚度和弯曲强度等生物力学指标的测定。结果表明：不同产量水平随基本苗的过量增加,拔节期最高分蘖峰值的增加,群体倒伏时间提早,面积加大。虽然成穗数差异不大,但穗粒数降低,特别是千粒质量明显降低,产量递减。表明受该地区自然条件与种植制度的制约,合理的基本苗（450万/hm2左右）,通过返青后适期适量的水肥调控,保持稳健的最高分蘖数是关系高产不倒的两个重要的群体临界指标。研究明确了倒伏与基部第2茎节形态结构、株高、节间距与力学指标弯折力、惯性矩、弹性模量、抗弯刚度、弯曲强度都呈负相关。而茎秆干质量、茎秆外径、壁厚与弯折力、惯性矩、弹性模量、抗弯刚度、弯曲强度都呈正相关。说明随着基本苗的过量增加与拔节最高茎蘖数的增加,基部茎秆力学负荷降低,就会发生倒伏。研究筛选出与茎节抗倒、群体质量、植株形态结构以及产量结构关系密切的两个力学指标,即“弯曲强度”与“弹性模量”,可作为抗倒育种或株型育种以及高产群体架构设计的参考指标。 相似文献
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茎秆作物抗倒伏生物力学评价研究及关联分析 总被引：28，自引：10，他引：18
研究茎秆作物的生物力学性质可为相关作物机械化生产及产品深加工等作业装备提供设计参数,还能对茎秆作物优种筛选进行评价指标。该文在高秆、中秆和矮秆3个品种,4个不同生长期的小麦茎秆弯折性能试验,2个玉米品种灌浆高峰期弯折性能试验,2个高粱品种灌浆高峰期弯折性能试验,2个大豆品种结荚鼓粒期弯折性能试验数据的基础上,进行了茎秆作物抗倒伏特性的生物力学评价指标研究及关联分析。采用灰色关联法分析了不同生长期惯性矩、弹性模量、抗弯刚度、抗弯强度等与弯折性能有关的各生物力学指标与抗倒性之间的关系,并以小麦茎秆为例对评价指标进行了权重数确定和检验。结果表明：茎秆作物不同品种茎秆生物力学性能指标中的弹性模量、抗弯折强度和惯性矩对倒伏的影响程度基本相当,抗弯刚度对倒伏影响较小。该结论为茎秆作物生物力学评价提供了新的途径和方法。 相似文献
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DCPTA和ETH复配剂对玉米茎秆力学特性及籽粒产量的影响 总被引：3，自引：0，他引：3
为探究植物生长调节剂对玉米茎秆力学特性的影响以及与产量的关系,以东农253为试材,在玉米9叶期喷施2种外源物质:玉黄金、自配的DCPTA和ETH复配剂(代号KP),以喷施清水为对照(CK)。喷施处理后,分别在玉米抽雄前10 d、抽雄期、灌浆初期、乳熟期和完熟期取其茎秆研究力学特性,并在收获期测产。结果表明,与CK相比,喷施KP和玉黄金后,株高分别下降8.87%和6.65%,穗位高分别下降17.79%和4.04%,扁率最高下降45.86%和15.86%;茎秆横折强度、穿刺强度、单位节间长度干物重、节间横截面积及皮厚最高分别提高150.17%、103.56%、215.79%、85.03%、110.48%和115.46%、56.44%、53.33%、76.19%、27.41%。收获期玉黄金处理下籽粒水分含量较CK显著下降4.97%。KP和玉黄金处理下的产量较CK增加9.23%和5.78%。相关性分析表明,植物生长复配剂处理后茎秆的皮厚、穿刺强度、横折强度、横截面积、单位节间长度干物重和田间致倒伏推力与产量呈正相关;株高、穗位高和扁率与产量呈负相关。由此可见,植物生长复配剂可以提高玉米茎秆强度以及籽粒产量。本研究结果为黑龙江玉米化控高效栽培提供了理论依据。 相似文献
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为了探究水稻垄作栽培和稻-鱼-鸡共生模式的结合对水稻茎秆倒伏、穗部性状及产量的影响,本文通过设计常规水稻垄作栽培(CK)、水稻垄作养鱼(RF)、水稻垄作养鸡(RC)和水稻垄作养鸡养鱼(RFC)的田间对比试验,研究垄作稻-鱼-鸡共生模式下水稻茎秆倒伏、穗部性状和实际产量的变化。结果表明:2年中4个处理的水稻株高、株鲜重、重心高度和节间长的均值整体无显著性差异。与CK处理相比, RFC和RC处理水稻茎秆节间外径、节间壁厚、穗长和穗鲜重虽呈增加趋势,但均值整体也无显著性差异;水稻产量也保持稳定。RF处理水稻茎秆节间外径、壁厚、穗长和穗鲜重均呈降低趋势,且2019年穗鲜重达显著降低(P0.05);水稻产量2年平均降低为29.98%(P0.05),其余均值整体无显著性差异。2年中RFC和RC较CK处理水稻节间茎秆抗折力平均增加19.69%和8.10%,且2年中RFC的第4和第5节间茎秆抗折力显著增加(P0.05);而RF处理茎秆抗弯截面模量和抗折力整体均呈降低趋势,但均值整体变化不显著。RFC和RC较CK处理水稻茎秆节间最大应力均值降低为17.85%和15.08%,倒伏指数均值降低为4.35%和4.26%,但未达显著水平;RF处理茎秆节间倒伏指数平均增加11.47%,且2018年第3和2019年第2～5节间均达显著性差异(P0.05)。综上所述,垄作稻-鱼-鸡共生和垄作稻-鸡共生模式能够提高水稻穗长和穗鲜重,稳定水稻产量,增加水稻茎秆节间外径和壁厚,提高茎秆抗折力和抗弯截面模量,降低茎秆最大应力和倒伏指数,从而具有一定的壮秆效应和抗倒伏能力。 相似文献
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种植密度对川中丘陵夏玉米茎秆性状及产量的影响 总被引：9，自引：2，他引：7
以玉米品种‘正红505’为材料,设置4.50万株·hm~(-2)、5.25万株·hm~(-2)、6.00万株·hm~(-2)、6.75万株·hm~(-2)、7.50万株·hm~(-2) 5个密度处理,研究种植密度对川中丘陵夏玉米茎秆性状及产量的影响。结果表明:随种植密度的增加,株高、穗位高、节间长、茎节长粗比逐渐增加,茎粗、茎粗系数、节间干重、单位茎长干物质重、茎秆压碎强度和外皮穿刺强度逐渐减小,除穗位高外,其余各性状均存在显著性差异;其中,当种植密度增加到7.50万株·hm~(-2)时,第1、3、5茎节的外皮穿刺强度分别较4.50万株·hm~(-2)显著降低27.10%、22.78%和30.80%。在本试验设置的密度范围内,玉米产量随密度的增加而先增后减,在6.00万株·hm~(-2)处获得最大值,与4.50万株·hm~(-2)相比,6.00万株·hm~(-2)显著增产12.02%。随种植密度增加,玉米穗长、穗粗、成穗率、穗粒数和千粒重显著降低,有效穗数和秃尖长显著增加。相关分析表明,茎秆压碎强度与外皮穿刺强度呈极显著正相关(r=0.93**),且茎秆压碎强度和外皮穿刺强度分别与茎粗、茎粗系数、节间粗、节间干重和单位茎长干物质重呈显著或极显著正相关,而与株高、节间长和茎节长粗比呈负相关或极显著负相关。其中,茎秆农艺性状与茎秆压碎强度的相关性更好。单株产量与茎粗、茎粗系数、节间粗、节间干重、单位茎长干物质重、茎秆压碎强度和外皮穿刺强度呈显著或极显著正相关,与节间长和茎节长粗比呈显著负相关。逐步回归分析表明,茎粗系数和单位茎长干物质重对茎秆压碎强度的影响最大。综上所述,种植密度是影响玉米茎秆性状和产量的重要因素,适当增加种植密度可以显著增加玉米群体产量,茎粗系数和单位茎长干物质重可以作为评价玉米茎秆抗倒伏能力的重要农艺指标。 相似文献
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基于核磁共振技术检测小麦植株水分分布和变化规律 总被引：6，自引：6，他引：0
为研究活体冬小麦植株水分的分布状况和连续变化过程,该研究利用核磁共振无损、非侵入的技术优势,分析了小麦各器官T2弛豫谱特征及其反映的代谢特性,分别推求出小麦叶片、茎秆和穗的信号幅值与被检测器官纯水含量以及鲜质量的回归函数关系,在此基础上建立了测量活体冬小麦植株各器官湿基含水率的检测方法。对活体植株各器官湿基含水率核磁共振检测方法的可靠性验证表明,由核磁共振法和烘干法测定的小麦叶片、茎秆和穗的湿基含水率均方根误差分别为：5.3%、3.5%、3.3%。然后将该检测方法用于监测同一株冬小麦各器官湿基含水率的长期变化和日变化过程,结果显示,乳熟期至成熟期,小麦各个器官的湿基含水率均逐渐减小,而叶片湿基含水率的日变化则呈现先减小后增大的趋势。乳熟期叶片的湿基含水率由8:00逐渐减少,且在14:00－16:00达到最低值后开始恢复,于20:00恢复至当日初始水平。成熟期叶片湿基含水率由8:00逐渐减少,但在20:00不能恢复至日内的初始水平。由于这套基于核磁共振技术的小麦湿基含水率检测方法能够对同一植株进行活体无损连续监测,因此该研究的结果能够更直接更准确地揭示冬小麦植株体内水分的连续变化规律和植株衰老过程,从而为研究冬小麦健康生长耗水规律和制定合理的灌溉制度提供理论基础。 相似文献
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四川玉米生理成熟后抗倒性能变化及其影响因素 总被引：1，自引：0，他引：1
《中国生态农业学报》2021,(9)
玉米茎秆强度下降是造成生理成熟后玉米倒伏的重要因素。为明确玉米生理成熟后茎秆强度变化及影响因素,本试验以玉米品种‘正红6号’为材料,设置不同密度处理,通过研究其生理成熟后茎秆强度、单位长度干重、含水率等变化规律,分析影响生理成熟后茎秆强度的关键因素,为机械粒收技术推广提供科学指导。结果表明,玉米生理成熟后节间茎秆强度逐渐下降,随着时间推移,降低幅度逐渐减小;生理成熟后玉米茎秆单位长度干重、含水率逐渐降低,节间长粗比略有增加。不同密度间茎秆强度差异显著,生理成熟后茎秆强度下降幅度不同,在4.5万～10.5万株·hm~(-2)密度范围内,随着密度增加,茎秆强度下降幅度呈降低趋势,低密度茎秆强度下降幅度大于高密度处理。种植密度增加导致玉米茎秆单位长度干重显著降低,节间长粗比显著增加。本研究发现玉米生理成熟后茎秆单位长度干重降低是茎秆强度降低的主要原因;种植密度增加显著降低了茎秆强度,同时随着站秆时间的延长,茎秆强度进一步降低,增加了玉米倒伏风险。因此,合理密植、适期收获能降低因生理成熟后站秆能力下降而导致倒伏的风险。 相似文献
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【目的】以富士（Fuji）、 秦冠（Qinguan）嫁接在平邑甜茶（Malus hupehensis Rehd.）上的当年生盆栽苗为试验材料,采用砂培方法,研究了缺氮胁迫和干旱对富士和秦冠生长情况、 光合参数、 植株各部位氮磷钾含量及氮素利用效率的影响,分析比较了低氮干旱条件下富士和秦冠生长及氮素利用的差异,以期为果树生产高效肥水利用提供理论指导。【方法】试验共设四个处理: 正常氮正常水（ZZ）、 低氮正常水（DZ）、 正常氮干旱（ZG）、 低氮干旱（DG）。氮素和水分均设置两个水平,分别为正常氮（6 mmol/L NO-3-N）、 低氮（0.3 mmol/LNO-3-N）、 正常供水（保持盆中砂子相对含水量为饱和含水量的80%~85%）、 干旱处理（保持盆中砂子相对含水量为饱和含水量的60%~65%）。【结果】富士和秦冠的生物量（茎和叶）、 株高茎粗等生长指标以及光合速率、 气孔导度、 蒸腾速率均为正常氮正常水（ZZ）＞低氮正常水（DZ）＞正常氮干旱（ZG）＞低氮干旱（DG）,并且相对应处理下秦冠的以上指标均高于富士;正常供水下,缺氮处理使富士、 秦冠的根冠比比正常氮处理均有所增加,富士提高了2.05%,秦冠提高了22.40%。富士和秦冠的氮、 磷、 钾含量均表现出正常氮正常水（ZZ）＞低氮正常水（DZ）＞正常氮干旱（ZG）＞低氮干旱（DG）; 氮、 钾元素含量在植株各部位的分布顺序依次是叶＞根＞茎,磷元素则是根＞叶＞茎;光合氮素利用效率（PNUE）和氮素利用效率表现为秦冠处理之间差异极显著,富士处理之间差异不显著;秦冠的PNUE和NUE明显高于富士,在低氮正常水（DZ）处理下,秦冠氮肥利用率比富士高42.07%,在低氮干旱（DG）处理下高64.14%;低氮胁迫下富士和秦冠的NUE显著提高,并且秦冠提高的幅度高于富士。【结论】施用氮肥能够显著提高富士与秦冠的干物质量,同等水肥条件下,秦冠生长优于富士;水分亏缺会减少叶片对氮的吸收,干旱条件下适度增施氮肥,可提高果树的抗旱能力;低氮干旱胁迫下秦冠的生长指标、 光合指标及氮素利用效率指标均优于富士,表现出较强的抗低氮干旱胁迫的能力。 相似文献
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Kyle Devey Michael Mucalo Gordon Rajendram Joseph Lane 《Communications in Soil Science and Plant Analysis》2015,46(4):72-80
Laser-induced breakdown spectroscopy (LIBS) is a new technique for the analysis of plant material. This study investigates the application of LIBS to pasture-based plant samples. The LIBS measurements were obtained from pelletized pasture samples (100 samples) that had been also analyzed by inductively coupled plasma–optical emission spectroscopy (ICP-OES) following microwave digestion for calibration and comparison purposes. Comparisons for elements sodium (Na), potassium (K), magnesium (Mg), calcium (Ca), manganese (Mn), iron (Fe), copper (Cu), zinc (Zn), boron (B), phosphorus (P), and sulfur (S) showed that LIBS could be used for almost all the standard profile total elements with concentrations down to low mg/kg levels (observed error of Na: 0.024 percent, K: 0.18 percent, Mg: 0.016 percent, Ca: 0.073 percent, P: 0.017 percent, Mn: 31 mg/kg, Fe: 150 mg/kg, Zn: 6.6 mg/kg, and B: 1.1 mg/kg). Elemental analysis at less than mg/kg levels was not possible using LIBS. The elements S and Cu were particularly difficult to analyze with reliability using LIBS at the concentration levels found in the plant samples. Replacing microwave digestion and subsequent ICP analysis with a direct analysis of dried plant samples using LIBS has the potential to improve the productivity and reduce the cost of testing. 相似文献
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《中国生态农业学报》2014,(8)
正The Center for Agricultural Resources Research(CARR),the Institute of Genetics and Developmental Biology(IGDB),Chinese Academy of Sciences,invites applicants for several research group leader positions.CARR is one of the research organizations in Chinese Academy of Sciences(CAS).We seek nominations and applications from individuals who have expertise and a record of accomplishment in research areas related to ecology,agro-hydrology, 相似文献
14.
Aleš Lebeda Ivana Doležalová Eva Křístková Barbora Mieslerová 《Genetic Resources and Crop Evolution》2001,48(2):153-164
Staff members of the Department of Botany of Palacký University in Olomouc and Gene Bank Department – Workplace Olomouc, Research Institute of Crop Production in Prague, Czech Republic, conducted an expedition in seven European countries (Austria, Czech Republic, France, Germany, Italy, the Netherlands, Switzerland) in August/September 1999 to collect wild Lactuca spp. germplasm and study its geographic distribution, ecology and biodiversity. During the mission, more than 600 locations were visited resulting in the collection of 602 seed samples (accessions) of wild Lactuca species and 13 seed samples of related genera (Chondrilla and Mycelis). Lactuca serriola f. serriola, L. serriola f. integrifolia, L. saligna and L. viminea subsp. chondrilliflora were prevalent in southern Europe (Italy, France), however, only L. serriola was common in central and western Europe (Austria, Czech Republic, Germany, Netherlands, Switzerland). The greatest diversity of Lactuca species was found in France, where also the most seed samples (165) were collected. The most characteristic habitats with a high density of Lactuca spp. populations were observed along roads and highways, grassy ditches, ruderal communities, and dust-heaps. Natural infections by powdery mildew (Erysiphe cichoracearum) and downy mildew (Bremia lactucae) on some wild Lactuca spp. were observed. Recent observations concerning the geographic distribution, population structure, habitats, and natural occurrence of diseases of Lactuca spp. are discussed. This assemblage of genetic resources of Lactuca spp. can serve as the basis of future studies of species diversification, spatial population structure, plant microevolution, domestication processes, and genetic variability of host-parasite interactions. 相似文献
15.
M.A. Callaham Jr. J.M. BlairT.C. Todd D.J. KitchenM.R. Whiles 《Soil biology & biochemistry》2003,35(8):1079-1093
The responses of tallgrass prairie plant communities and ecosystem processes to fire and grazing are well characterized. However, responses of invertebrate consumer groups, and particularly soil-dwelling organisms, to these disturbances are not well known. At Konza Prairie Biological Station, we sampled soil macroinvertebrates in 1994 and 1999 as part of a long-term experiment designed to examine the effects and interactions of annual fire, mowing, and fertilization (N and P) on prairie soil communities and processes. For nearly all taxa, in both years, responses were characterized by significant treatment interactions, but some general patterns were evident. Introduced European earthworms (Aporrectodea spp. and Octolasion spp.) were most abundant in plots where fire was excluded, and the proportion of the total earthworm community consisting of introduced earthworms was greater in unburned, unmowed, and fertilized plots. Nymphs of two Cicada genera were collected (Cicadetta spp. and Tibicen spp.). Cicadetta nymphs were more abundant in burned plots, but mowing reduced their abundance. Tibicen nymphs were collected almost exclusively from unburned plots. Treatment effects on herbivorous beetle larvae (Scarabaeidae, Elateridae, and Curculionidae) were variable, but nutrient additions (N or P) usually resulted in greater densities, whereas mowing usually resulted in lower densities. Our results suggest that departures from historical disturbance regimes (i.e. frequent fire and grazing) may render soils more susceptible to increased numbers of European earthworms, and that interactions between fire, aboveground biomass removal, and vegetation responses affect the structure and composition of invertebrate communities in tallgrass prairie soils. 相似文献
16.
Thomas Larsen Jesper Luxhøi Jakob Magid Lars Stoumann Jensen Paul Henning Krogh 《Biology and Fertility of Soils》2007,44(1):59-68
We have studied the effect of anaerobically digested (ADMSW) and composted municipal solid waste (CMSW) on mineralization
and foodweb dynamics to verify the hypothesis that ADMSW would immobilize N right after addition to soil in contrast to addition
with CMSW. Another hypothesis was that the mesofauna (enchytraeids and microarthropods) would stimulate N release from the
decomposer community. We measured excretion of -N and urea-N from the mesofauna and hypothesized that enchytraeids would release urea. ADMSW and CMSW were amended to pots
with sandy loam and barley. The pots were divided into treatments with or without mesofauna. Mesofauna, plant N and biomass,
soil N and ergosterol (fungal biomass) were measured over a 113-day period of four equidistant samplings. Soil respiration,
N mineralization and N release by the mesofauna were modelled from concurrent studies. ADMSW- and CMSW-treated soils initially
(<20 days) immobilized N. The amendments did not increase plant growth substantially, and this was probably due to N-limitation
in the early stages of plant growth. Enchytraeid abundance was about three times higher in ADMSW- than CMSW-treated soils,
indicating that ADMSW contained more labile compounds, bacteria, and microfauna. The mesofauna did not affect N-content, but
the cumulated -N excreted by the mesofauna was estimated to be substantial and about one-fifth of total plant N in ADMSW. An explanation
for this discrepancy might be that in the absence of the mesofauna, other members of the detrivore and microbivore community
performed the mesofauna’s function. Neither enchytraeids nor microarthropods excreted urea. 相似文献
17.
《中国生态农业学报》2014,(7)
正The Center for Agricultural Resources Research(CARR),the Institute of Genetics and Developmental Biology(IGDB),Chinese Academy of Sciences,invites applicants for several research group leader positions.CARR is one of the research organizations in Chinese Academy of Sciences(CAS).We seek nominations and applications from individuals who have expertise and a record of accomplishment in research areas related to ecology,agro-hydrology, 相似文献
18.
《中国生态农业学报》2014,(6)
正The Center for Agricultural Resources Research(CARR),the Institute of Genetics and Developmental Biology(IGDB),Chinese Academy of Sciences,invites applicants for several research group leader positions.CARR is one of the research organizations in Chinese Academy of Sciences(CAS).We seek nominations and applications from individuals who have expertise and a record of accomplishment in research areas related to ecology,agro-hydrology, 相似文献
19.
Grete Skrede Berit Karoline Martinsen Anne-Berit Wold Stein-Erik Birkeland Kjersti Aaby 《Acta Agriculturae Scandinavica, Section B - Plant Soil Science》2013,63(3):193-208
Abstract A 3-year study was carried out to investigate quality parameters in 14 tree fruit and berry species grown in southern Norway. The species were blueberry, apple, aronia, sour cherry, sweet cherry, red raspberry, strawberry, blackcurrant, gooseberry, red currant and elderberry, harvested along with wild bilberry, cloudberry and lingonberry. Significant differences between species were identified for all quality parameters. The coefficient of variation between species was lowest for pH (12.5%), dry matter (18.9%) and soluble solids (25.3%), followed by titratable acids (59.3%), total phenolics (83.8%), antioxidant capacity FRAP (85.7%) and antiradical power by the DPPH-assay (97.8%), total monomeric anthocyanins (132%) and ascorbic acid (137%). Average coefficient of variation within species were lower and ranged from 4 (pH) to 62% (ascorbic acid). Only the FRAP values were significantly affected by harvesting year with lower levels in 2004 than in 2005 and 2006. There were significant interactions between species and harvesting year for dry matter, soluble solids, pH, ascorbic acid and FRAP. The results indicate generic ranges in composition within species independent upon growing location and climate, and the composition of the tree fruits and berries is not likely to deviate from these ranges. It is concluded that desirable composition of tree fruits and berries and their products should primarily be achieved by selection among species rather than searching fors broadened variation within individual species. 相似文献
20.
《Communications in Soil Science and Plant Analysis》2012,43(7):865-877
Potassium (K) fixation and release in soil are important factors in the long-term sustainability of a cropping system. Changes in K concentration and characteristics of K fixation and release in rhizosphere and nonrhizosphere soils in the rapeseed (Brassica napus L.)–rice (Oryza sativa L.) rotation were investigated using a rhizobox system. The concentrations of different forms of K in both rhizosphere and nonrhizosphere soils decreased with plants compared to without plants, regardless of K fertilizer application. Potassium uptake by crops mainly came from the rhizosphere soil. In the treatment without K fertilizer (–K), the main form of K supplied by the soil to the crops was 1.0 mol L?1 nitric acid (HNO3) nonextractable K, followed by nonexchangeable K, and then exchangeable K. In the treatment with K fertilizer (+K), the main K forms supplied by the soil to the crops were exchangeable K and nonexchangeable K. The amount and rate of K fixation after one cycle of the rapeseed–rice rotation was greater in rhizosphere soil than in nonrhizosphere soil. The amount and rate of K fixation of soil in the +K treatment were significantly less than in the –K treatment. The cumulative amounts of K released with 1.0 mol L?1 ammonium acetate (NH4OAc) and 1.0 mol L?1 HNO3 extraction increased with the increasing numbers of extractions, but the K-releasing power of soil by successive extraction decreased gradually and finally became almost constant. The release of K was less in rhizosphere soil than in nonrhizosphere soil. The release of K in the +K treatment was similar to that in the –K treatment in rhizosphere soil, but the K release in nonrhizosphere soil was greater with the +K than the –K treatment. Overall, the information obtained in this study will be helpful in formulating more precise K fertilizer recommendations for certain soils. 相似文献