Effect of Five Phosphate Rocks on Red Clover (Trifolium pratense L.) Yield in Pot Trial

Abstract

Phosphorus (P) availability in five phosphate rocks with different P solubility was compared with that in single superphosphate and superphosphate+lime in a pot experiment with red clover as test plant on a Lamellic Arenosol with sand soil texture and on a Haplic Luvisol with clay loam soil texture, both strongly acid with low P supply. Phosphorus rates in the pot experiment were 0, 100, 400, and 1600 mg total P₂O₅ kg^?1. On both soils, there was a weak correlation between total added P and red clover P responses. If P solubility of the PRs was also taken into account, the correlation between formic acid–, citric acid–, or neutral ammonium citrate–soluble P amounts added and red clover responses became much stronger. Soil P availability was estimated by water, Olsen, Lakanen‐Erviö, and ammonium lactate tests. Among the P extractants studied, Olsen soil P test gave the best correlation with red clover yields.     

Yield and Quality of Mixed Seed Crops of Timothy ( Phleum pratense ) and Clovers ( Trifolium spp.) in an Organic Cropping System

Seed production of timothy ( Phleum pratense L.) in mixed crops with alsike ( Trifolium hybridum L.), white ( T. repens L.) or red ( T. pratense L.) clover was evaluated in an organic cash crop system. No fertilizer was applied except for household compost in the sowing year. While the first year crops of the alsike clover/timothy and red clover/timothy leys were harvested for clover seed, the first year crop of the white clover/timothy ley and all second year crops were harvested for timothy seed. The botanical composition of the alsike clover/timothy crop averaged 89/11 in the first ley year, and 8/92 in the second year. The corresponding yields averaged 443 kg ha -1 clover seed and 849 kg ha -1 timothy seed, respectively. Second year seed yields of timothy from mixtures with red and white clover were, in turn, 7% higher and 44% lower than from the corresponding mixture with alsike clover. First year seed yields of alsike clover from the alsike clover/timothy combination, and first year yields of timothy from the timothy/white clover combination were mostly rejected because of insufficient purity. In contrast, first year seed yields of red clover from the red clover/ timothy combination, and second year yields of timothy from all combinations, never failed to met the international requirement of maximum 1% contamination of one particular species in certified seed.     

不同氮磷用量对红枣果实品质和产量的影响

水资源匮乏与土壤肥力不足一直是阻碍新疆红枣果业发展的重大问题。为探究不同氮磷用量对红枣产量和品质的影响,给红枣树合理施肥提供指导。在南疆阿里尔市枣园,以主干结果型灰枣树为研究对象,采用单因素随机区组试验设计,在滴灌条件下研究了不同施氮量和施磷量下灰枣果实可溶性糖、可滴定酸、糖酸比、Vc等品质指标与产量的变化。结果表明,各施氮处理吊干枣的可溶性糖含量、可滴定酸含量均明显高于鲜枣,但鲜枣的Vc含量和糖酸比却均明显高于吊干枣。随施氮量增加,吊干枣果实中可滴定酸含量、糖酸比均呈先降低后增加趋势。其中以施N 690.0 kg/hm2时吊干枣可溶性糖含量较高,糖酸比较低;施N 495.0 kg/hm2时吊干枣可滴定酸含量较低,糖酸比较低;施N 592.5 kg/hm2时鲜枣Vc含量较高,糖酸比较高,吊干枣产量最高,为8 061 kg/hm2。各施磷处理鲜枣的可溶性糖含量、可滴定酸含量明显低于吊干枣,但鲜枣的Vc含量明显高于吊干枣,糖酸比波动较大,变化无明显规律。随施磷量增加,鲜枣和吊干枣果实中可溶性糖含量和Vc含量均呈先增加后降低趋势;可滴定酸含量呈先降低后增加趋势;糖酸比鲜枣呈先增加后降低再增加趋势,吊干枣呈先降低后增加趋势。施P2O5 517.5 kg/hm2时吊干枣可溶性糖含量和鲜枣Vc含量较高,吊干枣产量最高,为6 983 kg/hm2。施P2O5 435.0 kg/hm2时吊干枣可滴定酸含量较低。综合可见,施N 495.0 kg/hm2、P2O5 517.5 kg/hm2 为南疆枣园最优施肥量。     

不同形态氮肥对磷肥生物有效性的影响

利用盆栽试验研究了潮土中不同形态氮肥对磷肥生物有效性的影响。结果表明:不同形态氮肥处理均有抑制油菜生长初期磷素累积的作用,氯化铵处理抑制作用最突出,其次是尿素,再次是硫酸铵、硝酸铵和硝酸钙处理;油菜生长后期不同形态氮肥处理均逐渐显著促进油菜的磷累积,但氯化铵处理的促进作用仍然低于其它氮肥处理,这与不同形态氮肥处理对油菜生长的影响较一致。土壤有效磷含量受不同形态氮肥处理影响较小,而水溶性磷含量因施用不同形态氮肥均表现显著地下降,氯化铵和硫酸铵处理使土壤水溶性磷下降较多,硝酸铵、硝酸钙和尿素处理使土壤水溶性磷下降较少。     

模拟盐度变化对人工湿地脱氮除磷效果的影响

为探究人工湿地处理含盐生活废水的可行性,本研究构建了小尺度的人工湿地模拟系统,比较了不同盐度(0.0%、0.5%、1.0%、1.5%、2.0%)下人工湿地芦苇的生长情况以及几种典型污染物的去除效果。结果表明:①盐度对人工湿地中芦苇生长的影响表现出"低盐促进"、"高盐抑制"的特点,在0.5%进水盐度下,芦苇有最高株高1.22 m和最大基径0.48cm;②人工湿地对COD的去除率总体表现为随盐度的升高先升高后降低,在盐度为0.5%时,COD去除率达到最高84.86%;③当进水盐度为0.5%时,人工湿地对氮磷的去除几乎没有受到盐度的抑制;当进水盐度高于1.0%,随着盐度的升高,TN(总氮)、NH_4~+-N、NO_3~–-N、TP(总磷)的去除率均显著降低(P0.05),在2.0%盐度下分别下降到了44.40%、58.89%、49.23%、49.49%,相较0.0%盐度时分别降低了38.5%、23.4%、23.8%、19.2%。④不同污染物受盐分抑制程度不同,氮比磷更容易受到盐分的抑制,NH_4~+-N比NO_3~–-N更容易受到盐分的抑制。     

施磷对花生积累氮素来源和产量的影响

利用盆栽试验和15N示踪技术,研究了不同施磷量对花生吸收土壤氮、肥料氮、大气固氮量及比例和产量的影响,并探讨其原因,可为花生生产中科学施肥提供理论依据和技术指导。结果表明,花生根系干物重和根系活力随着施磷量的增加而增大,根瘤数和根瘤鲜重均随着施磷量的增加而增多,植株各器官含氮量和15N丰度均随着施磷量的增加而增加,成熟期各器官氮素积累量和15N积累量均表现为随着施磷量的增加而增加。花生吸收肥料氮的比例在11.34%~12.69%之间,吸收土壤氮的比例在33.95%~47.75%之间,吸收大气氮的比例在40.90%~53.36%之间,增施磷肥减小了吸收土壤氮的比例,增加了吸收肥料氮和大气氮的比例。花生氮肥利用率在34.65%~47.53%之间,氮肥土壤残留率在31.42%~36.00%之间,氮肥损失率在21.05%~29.35%之间。氮肥利用率随着施磷量的增加而增大,而氮肥土壤残留率和损失率均随着施磷量的增加而减少。综上所述,增施磷肥由于显著提高了花生根系干物重、根系活力和根瘤数及根瘤鲜重,促进了花生植株对肥料氮的吸收和对大气氮的固定,进而提高了植株体氮素含量,促进植株生长发育,最终增加产量。     

氮磷输入对湿地生态系统碳蓄积的影响

湿地生态系统在全球碳循环中有着举足轻重的作用。由于湿地垦殖、农业化施用等人类活动和全球变暖、大气氮沉降的增多等自然因素的综合作用,大量氮磷营养物质进入湿地,这必将对湿地生态系统碳蓄积产生影响。本文综述了外源氮磷输入对湿地土壤碳库、植被碳库和枯落物分解的影响以及湿地生态系统碳循环的模型研究,并对以后发展趋势进行了预测。     

Effect of Daylength on the Nitrogen Status of Timothy (Phleum pratense L.)

Abstract

In two experiments timothy plants (Phleum pratense L., cultivars ‘Bodin’ and ‘Grindstad’, well established and vernalized in the first experiment and 7 weeks old in the second) were given daylength treatments with 12 h of photosynthetically active radiation (PAR) and day-lengthening light of low irradiance for from 2 to 13 weeks. Significant daylength effects on dry-matter, total nitrogen, nitrate and soluble protein content in the leaves of plants were demonstrated after only two weeks of treatment. The nitrogen and protein content decreased with increasing daylength, irrespective of the developmental stage of the plants. The dry-matter content increased with daylength when long days had induced generative development and decreased when all treatments at the same harvest were vegetative. The total nitrogen and protein per plant did not decrease from short to long days. The lower nitrogen and protein content in long days can therefore be regarded as a dilution caused by the increased dry-matter production found in these treatments. The observed effects of daylength on the ratio of assimilated nitrogen to assimilated carbon might be direct or indirect, since long days induce both enhanced dry-matter production and generative development in Bodin and Grindstad.     

不同氮磷配合下稻田田面水的氮磷动态变化研究

稻田田面水中N、P浓度是决定稻田N、P径流流失,N素的氨挥发与硝化-反硝化等各种损失途径的关键因子。采用田间试验方法研究了不同N、P配合下田面水中N、P动态变化。结果表明,田面水总N(TN)、总P(TP)和溶解态无机P(DIP)的浓度在施肥后很快达到峰值,之后迅速下降,其变化均可以用指数方程(Y=C0×e-kt)来描述。NH4 -N在施N后2~4天达到峰值,之后逐渐下降,6~7天后降至稳定。基肥施用后的NH4 -N浓度上升比分蘖肥和孕穗肥施用后慢,同时TN和NH4 -N浓度下降也慢。相同施N水平下,高P处理田面水的NH4 -N和TN浓度较优化处理高;相同施P水平下,高N和低N处理田面水的TP和DIP浓度也较优化处理高,这表明:当N、P其中之一超过或低于适合用量时,会促进另一养分的流失。施肥后田面水中TN、TP和DIP可作为稻田N、P流失的主要指标,应着重控制基肥施用后N、P的径流流失,以及追肥施用后尿素的水解速度。     

长期施用有机物料对旱地红壤磷组分及磷素有效性的影响

针对中亚热带第四纪红黏土发育的红壤旱地,建立了玉米单作系统等碳量投入有机物料的田间试验,利用不同的磷分级方法研究了不同有机物料施用对土壤磷组分的影响,构建了不同磷组分的含量与土壤全磷及有效磷之间的回归方程,明确了不同磷组分对土壤磷活化系数(PAC)及磷肥(表观和经济)利用率的影响。连续7a的试验结果表明:施用有机物料可以增加土壤PAC和磷肥利用率,并以秸秆猪粪9︰1配施(NPKS/M)处理效果最佳,显著高于常规施肥处理(NPK);施用有机物料显著提升了土壤有机磷含量,且与土壤有效磷含量显著正相关,其对土壤PAC及磷肥(表观和经济)利用率影响显著。施用有机物料通过影响土壤有机碳、全氮、碱解氮、交换性K⁺以及交换性Al³⁺含量影响土壤磷的有效性。     

两种根际促生菌在不同氮磷条件下对油菜生长 和养分吸收的影响

油菜是我国和世界主要油料作物,对氮磷肥需求量大,但是氮磷肥利用率低,会造成资源浪费和环境污染等问题。由于根际促生菌能够改善植物生长并提高养分吸收,近些年来不少生物肥料中添加有根际促生菌。采用土培试验,探究了两种根际促生菌(巨大芽孢杆菌和短小芽孢杆菌)在不同氮磷条件下对油菜生长和养分吸收的影响,以期为油菜肥料研制和施肥技术提供帮助。结果表明:油菜在缺氮或缺磷条件下的地上部干重仅为正常氮磷供应的20%;巨大芽孢杆菌在正常氮磷供应条件下改善了油菜生长,促进了油菜对P、K、Zn和B 4种营养元素的吸收,而在缺氮和缺磷条件下没有效果;短小芽孢杆菌在缺氮、缺磷和正常氮磷条件下均没有效果。因此,氮磷肥对油菜生长至关重要,巨大芽孢杆菌能够在适当氮磷供应的条件下发挥促生作用。     

不同磷水平对红壤溶液中锰、铝、镁和钙浓度变化以及小麦生长的影响

为了探明不同磷水平对红壤中土壤溶液主要金属离子变化的影响以及小麦对磷的响应,确定红壤中小麦适宜的施磷水平,采用原位提取土壤溶液和比较生物量的方法,监测了短期内红壤溶液中主要金属离子浓度变化及小麦生物量的变化。结果表明:碳酸钙的加入可以显著升高酸性红壤的p H,土壤溶液中铝、锰和镁浓度显著低于未加碳酸钙处理;800 mg/kg磷处理后铝、锰、镁和钙的浓度要比未加磷处理分别至少降低47%、44%、37%和33%。随着施磷量的增加,小麦在200 mg/kg磷处理时积累的生物量最大,随后磷增加,小麦生物量反而降低。而加碳酸钙处理小麦地下部生物量随着施磷量增加则降低。结果表明碳酸钙不仅可以有效升高土壤p H,降低土壤溶液铝浓度,还降低土壤溶液中锰的浓度。磷的加入同样可以降低锰和铝的浓度,缓解铝和锰毒害。红壤中生长小麦的适宜施磷量为200 mg/kg。     

不同生育期增温对水稻产量及氮、磷含量的影响

人类活动导致全球温度上升,明确增温对水稻产量和氮、磷含量的影响,可为预测和评估未来气候条件下水稻产量及品质提供依据。选用泰瑞丰5号、镇稻16号两个品种水稻进行盆栽试验,分别在分蘖期、孕穗期、抽穗期、开花期和灌浆期将水稻置于较对照高5℃的生长箱中处理7 d,分析不同生育期增温对水稻产量及氮磷含量、氮磷收获指数的影响。结果表明,不同生育期增温显著影响水稻的产量构成因素,其中,孕穗期和抽穗期增温对水稻产量影响最大;孕穗期增温下泰瑞丰5号和镇稻16号的穗粒数、结实率和籽粒重最低。总体而言,与对照相比,不同生育期增温显著增加了泰瑞丰5号和镇稻16号茎、叶、壳、籽粒的氮含量(p0.05)。而不同生育期增温对水稻磷含量的影响取决于增温时期及水稻品种。与对照相比,分蘖期、抽穗期、开花期和灌浆期增温使泰瑞丰5号的氮收获指数显著降低,而抽穗期增温使镇稻16号的氮收获指数显著降低。与对照相比,抽穗期和灌浆期增温显著降低了泰瑞丰5号的磷收获指数,分蘖期和抽穗期增温显著降低了镇稻16号的磷收获指数。本研究结果表明,孕穗期和抽穗期是增温影响水稻产量和氮磷吸收的关键时期。     

合肥市绿地土壤氮磷有效性特点

以合肥市典型道路、公园和庭院绿地土壤为对象,测定分析了绿地土壤理化性状和氮磷有效性特点。结果表明,绿地表层土壤容重平均值为1．45g／cm^3,总孔隙度为43．6％;土壤电导率平均值为159μ S／cm;pH值多在7．5～8．5,碱性化明显。老城区土壤氮磷有效性显著高于政务新区,老城区表层土壤全氮和速效氮含量的平均值分别为1．38g／kg和4．52mg／kg,高出政务区18．9％和42．1％;全磷和速效磷分别为1009．3mg／kg和41．9mg／kg,分别是政务区的3．0和1．9倍。园林绿地土壤具明显的富磷特征。     

Floral procyanidins of the forage legume red clover (Trifolium pratense L.)

The chemical characteristics of the purified procyanidin polymers of the flowers of the forage legume red clover (Trifolium pratense L.) were studied by (13)C NMR, acid-catalyzed degradation with benzyl mercaptan, and electrospray ionization mass spectrometry (ESI-MS). The (13)C NMR showed that the fraction consisted of predominantly procyanidin polymers. The thiolysis reaction products indicated a mean degree of polymerization (mDP) of 9.3 with epicatechin (81%) as the abundant flavan-3-ol extension unit and the terminating units dominated by catechin (95%). ESI-MS showed a range of oligomeric procyanidin ions (DP of 2-11). The white clover floral prodelphinidins consist of terminal units with nearly equal proportions of epigallocatechin (52%) and gallocatechin (48%) and extender units showing epigallocatechin (56%) and gallocatechin (39%). The dramatic difference in the stereochemistry of the terminal and extender units observed for the red clover floral procyanidins contrasts with the mixture of cis and trans stereochemistry observed for white clover floral prodelphinidins.     

有机酸对红壤磷素吸附特性的影响

以不同供磷水平的旱地红壤为材料,探讨了柠檬酸、酒石酸和草酸对红壤磷素吸附特性的影响。试验结果表明,经有机酸培育后的红壤磷的吸附曲线与Langmuir方程吻合性很好,相关系数可达0.949~0.999。有机酸可使磷的吸附曲线类型发生转变,柠檬酸可使土壤磷的吸附等温线由第Ⅱ类型转化为第Ⅲ类型,酒石酸可改变CK与NPK处理的吸附类型,而草酸没有影响。柠檬酸可使土壤的Xm降低30%~75.3%,以PM处理中的降低程度最大。酒石酸和草酸却在不同程度上使土壤的Xm增大,二者可使Xm分别增加0.8~2.3倍和0.1~0.3倍。三种有机酸均可减小平衡常数K值,提高土壤磷素的吸附饱和度,对磷素吸附特征值的影响程度大小顺序为:柠檬酸>酒石酸>草酸。在磷素利用率低的红壤中,增施有机肥或配施有机肥是提高土壤磷素生物有效性的最佳途径。     

生物炭施用对稻田氮磷肥流失的影响

针对宁夏引黄灌区稻田过量施肥导致土壤养分利用效率低的问题,通过田间小区试验,在优化施氮条件下(240kg·hm~(-2)),设4个生物炭水平(0、4500、9000、13500kg·hm~(-2)),研究施用外源生物炭对稻田氮磷流失和土壤养分含量的影响。结果表明:生物炭对稻田田面水氮素动态产生影响,表现为田面水中全氮、硝态氮含量随生物炭用量的增加而降低,铵态氮表现则相反;全氮和铵态氮的最大峰值出现在第1次追施氮肥后的第2天,最大值为34.86、8.28mg·L~(-1);硝态氮最大峰值3.31mg·L~(-1)出现在第2次追施氮肥后的第2天。随后均迅速下降,全氮含量在施氮肥后10d回到第1次追氮前的含量水平,并趋于稳定,铵态氮和硝态氮则在7d后。生物炭对田面水全磷未产生显著影响,全磷含量在第1次施氮肥后3d达到峰值,为3.69mg·L~(-1),之后迅速下降,6~7d后降至追氮前的含量水平,并趋于稳定。生物炭处理显著降低了稻田全氮流失量8.03%~13.36%,高量炭处理(13500kg·hm~(-2))显著提高了土壤全氮和有机质含量,提高幅度分别为41.2%和27.5%(P0.05)。说明生物炭对稻田磷流失、土壤全磷和速效磷含量无显著影响,对降低稻田氮素淋失表现出积极效果。     

磷肥在旱地红壤上的后期效应及其作用机制

红壤地区施入的磷肥很容易被吸附固定而留存于土壤中,降低磷肥利用效率,留存于土壤中的磷对土壤生态功能和作物养分供应的后续效应值得关注。基于旱地红壤长期施肥定位试验,探讨常规施肥处理（CK）以及短期施入不同磷肥量（P₂O₅,0、50、100、150和1 000 kg·hm^–2）多年后土壤养分、土壤氮循环过程和作物产量的变化特征。通过多元统计分析方法探讨不同磷肥处理下,土壤全碳、全氮和微生物生物量碳和氮转化过程的潜在速率以及产量等因子间的相互关系及其与磷的后期效应的关系。结果表明,在短期投入高剂量磷肥（1 000 kg·hm^–2,P1000）27年后,土壤全碳、全氮和微生物生物量碳与常规施肥处理相比无明显差异,但显著提高了土壤pH和氮循环相关过程速率,包括氮矿化速率（Nitrogen mineralization rate,N_min）、固氮酶活性（Soil nitrogenase activity,SNA）、潜在硝化速率（Potential nitrification rate,PNR）（P <0.05）,同时降低了净N₂O排放潜能（Net N₂O production rate,N_N2O）（P<0.05）。与不施磷（P0）和短期投入低剂量磷肥处理（50,100,150 kg·hm^–2）相比,P1000处理中,土壤有效磷（AP）、氮矿化速率、固氮酶活性、潜在硝化速率和潜在N₂O产生速率（P_N2O）分别增加了33.3%～76.4%、88.2%～388.1%、111.4%～4 826.3%、22.6%～152.4%和13.8%～78.9%（P <0.05）,同时净N₂O排放潜能也降低了64.6%～78.9%（P<0.05）,表现出明显的磷后效,且在作物生长季更为明显。相关分析和冗余分析表明AP和pH是影响以上土壤生物化学活性最主要的因子。近三年作物平均产量在所有处理中无显著差异,但与土壤TP、AP和pH呈显著正相关;但在长期尺度上（1992—2019年）,P1000处理相对于其他低磷处理累积增产效应达3%～23%。以上结果表明,酸性红壤中短期大量施用磷肥多年后,由于大量磷肥投入导致的土壤pH提升和磷的缓释效应,使得磷肥在促进土壤肥力、微生物活性和土壤氮循环转化活性方面表现出较明显的后期效应。     

Relating Morphologic and RAPD Marker Varlation to Collection Site Environment in wild Populations of Red Clover (Trifolium Pratense L.)

Although genotypic and phenotypic markers are used to describe genetic diversity, describing patterns of variationattributable to geographic differentiation is complex.We examined concordance between morphologic and RAPDmarker classification of 33 wild red clover populations collected from the Caucasus Mountains, Russia andcompared how morphologic and RAPD markers differed in their correspondence to collection site attributes.Wealso examined if wild red clover populations collected from sites located in areas more conducive to gene flow (i.e.adjacent to roads, or drainage systems) had the same concordance between morphologic and RAPD markers aspopulations collected from sites less conducive to gene flow.We measured 15 morphologic traits in a commongarden and carried out a Random Amplified Polymorphic DNA (RAPD) analysis. There was a significantdifference among the 33 populations for 14 out of 15 morphological traits. Morphology clustered the populationsinto classes that corresponded to three climate regimes. Classification schemes generated by morphologic andRAPD data did not coincide. Morphologic data corresponded with site data for populations collected at all sites.RAPD data corresponded to site data for only those populations collected at sites not conducive to gene flow. Apopulation's adaptation to collection site needs to be considered in using neutral markers to effectivelydiscriminating geographic differentiation.We discuss the practical lessons of this study on the effective collection,conservation and use of plant genetic resources.