三种不同绿肥的腐解和养分释放特征研究

利用网袋法模拟研究旱地条件下箭筈豌豆（Vicia sativas L.）、苕子（Vicia villosa Roth. Var.）、山黧豆（Lathyrus palustris L. Var. Pilosus ledeb） 三种绿肥的腐解和养分释放特征。结果表明,三种绿肥均在翻压15 d内腐解较快,腐解率均在50%以上,之后腐解速率逐渐减慢,翻压70 d时,箭筈豌豆、苕子和山黧豆的累积腐解率分别达71.7%、67.3%和74.1%。氮和钾在翻压10 d内释放较快,碳和磷在翻压15 d内释放较快,之后释放速率均减慢。箭筈豌豆、苕子和山黧豆在翻压70 d时的碳累积释放率分别为71.3%、67.0%和74.1%。三种绿肥的养分累积释放率均是K>P>N,在翻压70 d时钾的累积释放率均在90%以上,磷的累积释放率为73.3%～78.7%,氮的累积释放率为59.9%～71.2%,其中山黧豆的氮和磷累积释放率高于箭筈豌豆和苕子,而三种绿肥钾的累积释放率无显著差异。养分释放量结果表明,箭筈豌豆和苕子的养分累积释放量表现为K>N>P,而山黧豆表现为N>K>P,不同绿肥的养分累积释放量不同,山黧豆的氮累积释放量最高,箭筈豌豆的磷和钾累积释放量最高,苕子各养分的累积释放量都最低。     

黄河三角洲盐碱地毛叶苕子不同还田方式下 腐解及养分释放特征

绿肥在盐碱地土壤结构改良和地力提升上具有独特优势,但在黄河三角洲地区的相关研究较缺乏。通过种植试验和尼龙网袋模拟腐解试验,探究毛叶苕子作绿肥的养分供应能力以及在免耕覆盖和翻压2 种还田方式下的腐解、养分释放特征,以期为其合理利用提供参考。结果表明,黄河三角洲盐碱地种植毛叶苕子还田可以在较大程度上提供后茬玉米所需的氮、钾,但磷供应较少。2 种还田方式均表现为前期腐解和养分释放速率快,后期腐解和养分释放速率明显降低的趋势,养分累积释放率为钾> 氮> 碳> 磷。至还田81 d,覆盖还田和翻压还田的腐解率分别为53.7% 和74.8%,碳、氮、磷、钾释放率分别为75.6% ～ 81.0%、77.1% ～ 81.2%、59.8% ～ 63.2%、80.1% ～ 93.8%。与免耕覆盖还田相比,翻压还田的累积腐解率和前期的腐解速率显著较高。2 种还田方式的养分释放水平相当,但覆盖还田下各养分的快速释放期均短于翻压还田,持续供应养分能力更好。从保护土壤墒情和减少能源消耗的角度,毛叶苕子免耕覆盖还田具有一定优势,但可能受后期降雨、风等自然条件的影响更大,需要综合考虑和进一步的验证。     

陕北旱地毛叶苕子不同翻压量下腐解速率及养分变化特征

采用尼龙网袋法在陕北旱地进行田间腐解试验,研究了低(30000 kg/hm²)、中(45000 kg/hm²)、高(52500 kg/hm²)3个翻压量下毛叶苕子的干物质腐解规律和养分释放率,为合理确定绿肥翻压量和化肥配施量提供理论依据。结果表明:随着翻压时间的推移毛叶苕子腐解率呈前期迅速增加、后期缓慢的变化趋势,至试验结束时(75 d)各处理干物质的最终腐解率为61.98%～65.32%。氮、磷、钾均在翻压后的前10 d大量释放,至试验结束时氮累积释放率为69.10%～75.23%,磷累积释放率为72.25%～78.24%,钾累积释放率达81.62%～90.02%。不同翻压量下毛叶苕子氮、磷、钾的释放率和释放速率分别可用幂函数y=axb和指数衰减模型v=v0e-kx进行拟合,回归分析表明,不同翻压量下各养分最易达到的释放率均随翻压量的增大而降低,随着翻压量的增加,氮养分最大释放速率呈先增加后减小的趋势,磷的最大释放速率逐渐提升,钾的最大释放速率逐渐减少。增加翻压量对毛叶苕子磷完全释放的延缓效应最大(延缓145～167 d)、氮次之(延缓31～49 d)、钾最小(延缓26～38 d)。增加翻压量不会改变毛叶苕子整体的腐解及养分释放规律,但会对养分的释放率和释放速率产生影响,在实际生产中应充分结合作物需肥特性,确定毛叶苕子合理的翻压量。     

不同盐分土壤环境下绿肥腐解及养分释放动态研究

通过尼龙网袋埋田法研究了绿肥苕子、黑麦草在不同盐分滨海盐渍土壤中的腐解及养分释放规律。结果表明,不同盐分地块黑麦草干物质残留率、总有机碳含量和C/N总体高于苕子。苕子氮、钾在最初15天内快速释放,不同盐分地块的残留率分别为20.4%～34.0%和13.2%～18.1%,黑麦草钾在前45天释放了近90%,氮、磷释放持续整个腐解过程。低盐分地块绿肥钠的最终残留率为5.2%～7.6%,高盐分地块为36.2%～49.2%。不同盐分地块绿肥镁、钙、锌残留率以黑麦草高于苕子。铜的释放主要集中于前45天,之后趋于停滞。镁、铁、锰分别在腐解45～60天或45～75天出现养分富集现象。整体来看,禾本科绿肥干物质及养分残留率均高于豆科绿肥,高盐分明显阻滞了绿肥氮、钙、镁、铁、锰、铜和锌养分的释放。     

还田时期对绿肥用油菜腐解与养分释放规律的影响

探讨绿肥用油菜还田时期对干物质腐解与养分释放规律的影响,以期为华北地区油菜用作绿肥及后茬作物减氮增效提供理论依据。采用尼龙网袋埋田法研究了绿肥油菜初花期(G1)、盛花期(G2)和角果成熟期(G3)还田的干物质腐解与养分释放规律。结果表明,G1 处理油菜还田干物质量比G2 和G3 处理显著减少45.43% 和46.87%;G1 和G2 处理还田时碳含量低于G3 处理,G1 处理氮和磷含量最高,分别为28.17 和5.21 g/kg,钾含量表现为G1>G2>G3,G1 与G3 处理差异显著。绿肥油菜还田后分快速、中速和慢速腐解3 个阶段,持续期分别为还田后0 ～ 17、18 ～ 45 和46 ～ 123 d,阶段内累积腐解率分别达44.27% ～ 66.87%、12.56% ～ 29.18% 和4.49% ～ 13.81%,最终累积腐解率达60.53% ～ 91.87%;G1 和G2 处理间腐解率无显著差异,但显著高于G3 处理。绿肥油菜还田后碳、氮、磷和钾释放率与腐解率对应亦表现为前期快速释放、中期缓慢释放、后期趋于平稳的规律,且养分累积释放率均表现为钾> 碳> 氮> 磷。经腐解,G1 处理碳、氮、磷和钾累积释放率分别为94.70%、92.97%、88.76% 和93.26%,G2 处理分别为84.25%、86.32%、86.51% 和92.52%,G3 处理分别为72.52%、59.97%、68.54%和87.67%;G2 处理氮、磷和钾释放量最高,分别为125.15、22.88 和50.42 kg/hm²,且G2 处理氮、磷释放量显著高于G1 和G3 处理,G2 处理的钾释放量与G3 处理无明显差异。综上所述,华北地区绿肥油菜在盛花期还田干物质量大且氮、磷、钾释放量最高,是最适宜的还田时期,可为下茬作物减施化肥提供技术支撑与理论依据。     

油菜秸秆、紫云英绿肥及其不同比例配施还田的腐解及养分释放规律研究

试验以油菜秸秆和紫云英(Astragalus sinicus L.)为研究材料,通过盆栽模拟稻田条件,研究了油菜秸秆、紫云英绿肥及其不同比例混合处理腐解及养分释放动态。结果表明,腐解过程均呈现出前10~20 d分解较快,后期分解较慢并逐渐趋于平稳的规律。不同处理各养分的释放快慢不同,表现为钾磷氮碳,在翻压90d时钾的累积释放率为95.09%~97.17%,磷的累积释放率为62.65%~87.14%,氮的累积释放率为70%~76.48%,碳的累积释放率为39.53%~64.69%。翻压90 d后紫云英腐解率达到60.07%,油菜秸秆仅40.8%,混合紫云英后,混合处理的腐解程度加快,且腐解程度随紫云英量的增加而增加。     

不同绿肥种植模式下玉米秸秆腐解特征研究

【目的】玉米是中国第一大粮食作物,如何处理大量的玉米秸秆成为玉米种植区面临的关键问题之一,深入研究冬种绿肥对玉米秸秆腐解释放的影响,对农业可持续发展具有重要意义。【方法】采用尼龙网袋法,通过对红壤旱地空闲 (YCK)及紫花苜蓿(YZ)、 黑麦草(YH)、 肥田萝卜(YL)绿肥种植模式下玉米秸秆177 d的腐解量和养分释放的监测,分析玉米秸秆腐解速率及碳、 氮、 磷、 钾的释放规律。【结果】四种种植模式下,玉米秸秆腐解及养分释放均呈现前期快后期慢的规律,7 d的腐解和养分释放速率均达到最大。翻压177 d时,四种种植模式下(YCK、 YZ、 YH、 YL)玉米秸秆累积腐解量分别为23.41、 21.22、 20.86和20.95 g,玉米秸秆碳累积释放量分别为12.38、 11.07、 11.18、 11.36 g ,与YCK种植模式相比,YZ、 YH、 YL种植模式秸秆累积腐解量分别显著降低了9.3%、 10.9%、 10.5%,碳累积释放量则分别显著降低了10.6%、 9.7%和8.3%; 各处理氮累积释放量分别为479.46、 513.04、 442.58和530.20 mg,相比YCK种植模式,种植绿肥对玉米秸秆氮累积释放量的影响不显著,而YH种植模式较YZ和YL种植模式则显著降低了13.7%和16.5%。各处理磷累积释放量分别为58.10、 57.91、 58.47和59.47 mg,且YL种植模式较YCK种植模式显著提高了2.35%; 翻压 28 d时,各处理钾累积释放量为487.20、 444.85、 456.94和434.55 mg,分别占加入量的100.0%、 91.3%、 93.8%和89.2%,且三个种植模式均显著低于YCK种植模式,42 d时各处理的钾均全部释放。从玉米秸秆碳与氮、 磷、 钾比来看,翻压177 d时,与YCK种植模式相比,YZ和YL种植模式玉米秸秆碳氮比显著增加了102.8%、 91.6%; YZ、 YH、 YL种植模式碳磷比分别显著增加了48.4%、 72.4%、 147.0%。翻压 28 d时,YH种植模式玉米秸秆碳钾比较YL种植模式显著提高。【结论】玉米秸秆腐解及其养分释放速率均在翻压后第7天达到最大值,之后腐解和养分释放速率减缓。与空闲相比,种植绿肥能显著减缓玉米秸秆腐化和秸秆中碳和钾的释放,而种植紫花苜蓿和肥田萝卜能促进玉米秸秆氮素释放,种植黑麦草则减缓了玉米秸秆氮素释放。种植肥田萝卜能显著促进玉米秸秆磷素释放。冬季种植肥田萝卜既对玉米秸秆还田后氮素释放有一定促进作用,又能增加红壤中磷的有效性,同时还能减缓玉米秸秆钾的释放,使钾释放更为长效,是一种土壤培肥和秸秆养分释放较好的绿肥种植模式。     

光叶紫花苕子在烟田中的腐解及养分释放动态研究

利用尼龙网袋法研究光叶紫花苕子在烟田中的腐解和养分释放规律。结果表明,种植烤烟与否对光叶紫花苕子有机物质的腐解及养分释放动态无明显影响。其有机物质前2周腐解最快,第3～9周腐解速率中等,9周以后较慢,各阶段平均每周分解量分别占整个烤烟生育期内总分解量的29.86%～31.76%,2.52%～2.60%和1.41%～1.74%。光叶紫花苕子的碳、氮、钾释放量与翻压时间的关系可用对数方程拟合,前1～2周释放速率最快,其后释放速率迅速下降并趋于稳定。其中氮在前5周释放量占其整个烤烟生育期内总释放量的86.90%～92.27%,不存在后期氮供应过多导致烤烟成熟期推迟问题。光叶紫花苕子磷的释放速率较平稳,没有明显阶段性,其释放量与翻压时间关系可用直线方程拟合。经过整个烤烟生长季节的分解,光叶紫花苕子碳、氮、钾、磷的释放率分别达到68.76%～71.28%、69.57%～74.40%、97.98%～98.02%、41.26%～42.41%。烟田翻压光叶紫花苕子做绿肥时,应在烟苗移栽前择期翻压,并适当减少化肥用量。     

黄淮海地区绿肥与化肥配施对棉花生长和肥料利用率的影响

采用田间土柱模拟试验,研究了绿肥翻压与不同比例化肥配施对棉花生长和肥料利用效率的影响。结果表明: 翻压绿肥处理的棉花花铃期叶片SPAD值较不翻压绿肥显著提高,说明翻压绿肥对棉花叶片叶绿素含量有显著影响; 翻压绿肥有助于棉花氮、 磷和钾素的吸收。翻压绿肥处理与不翻压绿肥相比,籽棉产量增加近30%; 翻压绿肥与70%的化肥配施,不会降低棉株养分积累量、 籽棉产量和肥料利用率,且棉花的化肥农学效率明显高于配施100%和85%的化肥处理。     

大豆绿肥腐解特性研究

在田间条件下,采用埋入和覆盖尼龙袋子的方法,研究了大豆绿肥的腐解特征。结果表明,绿肥埋入和覆盖后随着时间的延长而逐渐分解,不同时间绿肥干物质量存在着显著差异。其腐解速率随着时间的延续而逐渐降低。大豆绿肥在种植玉米比不种植玉米的条件下腐解得快,在玉米施肥比玉米不施肥的条件下腐解得快,埋深10 cm比覆盖在地表腐解得快,但差异不显著。大豆绿肥使用量对其腐解速率几乎没有影响。大豆绿肥经过52 d的分解,在玉米施肥、不施肥和不种植玉米的条件下,其腐解率分别为59.63%、53.94%和43.61%。在整个腐解过程中,最初4 d腐解最快,8～16 d腐解速率中等,24 d至试验结束腐解最慢。3个阶段的腐解速率存在着显著差异。     

The effect of co‐composted cabbage and ground phosphate rock on the early growth and P uptake of oilseed rape and perennial ryegrass

Phosphorus (P) availability to crops in organic systems can be a major issue, with the use of readily available forms often restricted. One product that can be used in organically managed systems, that is also relatively easily accessible to growers, is phosphate rock, although its solubility and therefore crop availability is often poor. One possible approach to improve this situation is co‐composting phosphate rock with selected organic waste materials. Various ratios of phosphate rock and cabbage (Brassica oleracea L.) residues were co‐composted and the products tested at different rates of application. The effects were assessed over 12 weeks using oilseed rape (Brassica napus L.) and perennial ryegrass (Lolium perenne L.) as bioassay crops in a pot experiment. At harvest, estimates of P derived from cabbage and phosphate rock for the lowest of two rates of compost were ≈ 2 and 10 mg P pot^–1 for oilseed rape, compared to 5 and 2 mg P pot^–1 for perennial ryegrass, respectively. Roots tended to have higher P concentrations than shoots. The crops showed differences in their abilities to access various P sources, with oilseed rape effectively taking P from phosphate rock, whereas perennial ryegrass was more effective at accessing cabbage‐derived P (the main substrate in the compost). Oilseed rape was able to take up 20% of the total P applied as phosphate rock, whereas perennial ryegrass took up less than 5% of the total P applied from this material. Both pre‐ and post‐application solubilisation/transformation mechanisms were involved in supplying plant‐available P. Quantifying the relative contribution from individual P sources remains problematic even within this relatively simple system.     

The influence of N concentration and NO3/NH4 ratio on the growth of lima and snap bean and southern field pea seedlings

Abstract

Lima and snap beans and southern field peas were cultured in a modified Hoagland's solution for 14 days with N supplied as Ca(NO₃)₂ and/or (NH₄)₂SO₄ at three N concentrations and five ratios of NO₃ to NH₄. The ratio of NO₃/NH₄, rather than the N concentrations influenced seedling growth of these vegetable legumes. Maximum seedling growth of lima bean was generally obtained with all combinations of NO₃ and NH₄. A preference for 75% NO₃ and 25% NH₄ was observed for snap bean. Southern field pea growth was reduced only when all of the N was supplied as 100% NH₄. Ammonium toxicity symptoms, lesions and severe wilting, developed with snap bean and southern field pea within 14 days when cultured with 100% NH₄. Lima bean, though reduced in growth, exhibited a tolerance to the 100% NH₄ treatment.     

SALINITY-HEAVY METAL INTERACTIONS IN FOUR SALT-TOLERANT PLANT SPECIES

The concurrent effect of NaCl salinity and heavy metals [cadmium (Cd), chromium (Cr) and nickel (Ni)] on growth, sodium (Na), and heavy metal accumulation was assessed in four salt tolerant plant species. These were: barley (Hordeum vulgare L.), purslane (Portulaca oleracea L.), Inula crithmoides L., and Plantago coronopus L., all of which have documented potential for use in saline agriculture. Plants were grown in perlite and irrigated with salinized and non-salinized nutrient solutions (9 dS m^?1 and 18 dS m^?1) containing 2 ppm Cd, 4 ppm Cr, 10 ppm Ni, and a non-metal control. Salinity, Cd, and Ni caused a significant decrease in the dry biomass accumulation of P. oleracea, but had no effects on other plant species. Sodium accumulation was highest in P. coronopus and I. crithmoides, indicating pronounced halophytic properties. The presence of heavy metals reduced Na accumulation in H. vulgare and P. oleracea, but had no effect on P. coronopus and I. crithmoides, indicating that the Na-heavy metal interaction is plant-specific. Metal accumulation in the four plant species was generally enhanced by the 9 dS m^?1 treatment, but not by the 18 dS m^?1 treatment. This could indicate the presence of an ionic exclusion mechanism operating at high salinity levels that would operate indiscriminately on Na as well as on Cd, Cr, and Ni     

The effect of starter fertilizers on cotton production in legume residues

Abstract

Field and greenhouse studies were conducted to identify starter fertilizers which would enhance cotton seedling survival, growth, and yield in legume residues. Field studies were initiated in the fall of 1982 on a Norfolk sandy loam (Typic Paleudult) in the Upper Coastal Plain of Alabama. Winter annual legumes, crimson clover (Trifolium incarnatum L.) and hairy vetch (Vicia villosa Roth) were established as whole plots along with a winter fallow area. Split plot treatments consisted of O, N, P, K, NP, NK, and NPK starter fertilizers. The cotton (Gossypium hirsutum L.) was planted with a conservation tillage planting unit with in‐row subsoilers. The starter fertilizers were applied deep (8 to 10 inches) in the subsoil track. Greenhouse studies were also conducted with soil from whole plot areas top dressed with corresponding legume tissue at a rate of .9 g tissue/500 g soil. Seedlings in the greenhouse were rated for disease and emergence, and dry weights were recorded.

Cotton populations in field studies were lower in legume mulched than fallow soils in 1984. Application of starter fertilizers generally increased harvest populations, particularly the NK combination. In 1983, cotton growth was greater in vetch than other soils, but responses to starter fertilizers varied with analyses and years. Seed cotton yields were consistently high with P starter, although P did not always improve cotton stands and growth. When averaged across years and cover crops, yields were 3151, 3031, 2865, 2790, 2753, 2741, 2512, and 2364 for P, NP, P, NP, K, NPK, N and O, starter treatments respectively.

Greenhouse studies indicated that starter fertilizer improved cotton emergence in legume soils, but decreased emergence in fallow soils. Disease ratings of emerged seedlings were more severe when starter fertilizer was used than when it was not used. Thus, starter fertilizer increased emergence and survival, despite high disease ratings. Cotton seedling growth generally increased when poor emergence reduced cotton seedling competition.     

Plant availability of boron in acid soils as assessed by different extractants

Estimation of available‐boron (B) status through conventional methods in B‐deficient acidic Inceptisols and Entisols is often hampered because of their very low B content. In the present study, the extractability of available B by different extractants was tested in relation to soil properties. Plant availability of B was assessed with mustard (Brassica campestris L.) and wheat (Triticum aestivum L.) in pot experiments. Twelve soils with varying characteristics were extracted for available B with hot water (HW), hot CaCl₂ (HCC), KH₂PO₄ (PDP), tartaric acid (TA), and mannitol‐CaCl₂ (MCC). Mustard (cv. B‐9) and wheat (cv. PBW‐343) were grown with four levels of B (0, 0.25, 0.50, and 1.0 mg [kg soil]^–1). Dry‐matter accumulation and B concentrations were determined at pre‐flowering and full‐maturity stages for mustard and at panicle‐initiation and maturity stages for wheat. The extraction of B from the soils ranked HCC > HW > PDP > TA > MCC. The higher extractability with HW and HCC was likely due to higher temperature and that of PDP because of its phosphorus content, which facilitated the desorption of B. The low B extraction with MCC resulted from the poor mannitol‐B complex formation in acidic soils. The application of B increased dry‐matter accumulation, plant B concentration, and uptake at all B levels and growth stages in both crops with the responses being more pronounced during the early developmental stage. Based on linear correlations, Mallow's Cp statistics, and principal‐component analyses, HCC and HW were the best extractants for estimating available B in the acidic experimental soils.     

Effect of plant growth-promoting Bacillus sp. on color and clipping yield of three turfgrass species

A two-year irrigated field study was conducted to determine the effects of plant growth-promoting rhizobacteria (PGPR; Bacillus subtilis OSU-142 and Bacillus megaterium M3) as biofertilizer, and in combination with a chemical nitrogen (N) fertilizer, on turf color and clipping yield, and interaction of biofertilizer and chemical N fertilizers in perennial ryegrass (Lolium perenne L.), tall fescue (Festuca arundinacea L. Schreb.), and Kentucky bluegrass (Poa pratensis L.). The three turf species were tested separately in split-plot design experiments with three replications. Three fertilizer sources (ammonium nitrate only, ammonium nitrate + B. megaterium M3, and ammonium nitrate + B. subtilis OSU-142) were the main plots. N applications with monthly applications of 0.0, 2.5, 5.0, and 7.5 g N/m² were the subplots. Color ratings and clipping yields increased with increasing chemical N fertilizers in all species. Both Bacillus sp. significantly increased color ratings and clipping yields in perennial ryegrass and tall fescue. However, there were no significant differences among the three fertilizer sources in color and clipping yield of Kentucky bluegrass. The experiments showed that there is a small but significant benefit from applying biofertilizers for turf color, and that N fertilization may be reduced in some turf species when biofertilization are made for this purpose.     

Elemental composition of birdsfoot trefoil

Abstract

Developmental and environmental effects on mineral nutrient concentration in birdsfoot trefoil (Lotus corniculatus L.) are not well documented. In this study, elemental composition of two birdsfoot trefoil stands were determined from a late vegetative stage through reproductive growth. ‘Norcen’ birdsfoot trefoil was established on a Glyndon silt loam (coarsesilty, frigid Aeric Calciaquolls) in Roseau County, Minnesota (49°N), in 1980, and Norcen and ‘Leo’ birdsfoot trefoil were seeded on a Waukegan silt loam (fine‐silty over sandy or sandy‐skeletal, mixed, mesic Typic Hapludolls) near Rosemount, Minnesota (45°N), in 1981. Shoot and root samples were taken at approximately biweekly intervals in the year following establishment. Shoots were separated into stems, leaves, umbels, and seed.

Environment influenced the concentration of most elements. This environmental effect was generally consistent among plant parts for Ca, Mg, S, Na, and Mn; i.e., all parts had a lower elemental concentrations at Rosemount than at Roseau. The relationship between environments for P, K, Zn, and Cu concentrations varied with different plant parts; i.e., some”; plant components had element concentrations higher at the southern than northern location, whereas other components had element concentrations that showed the converse. Although most elements were less concentrated with advancing developmental stage, environment modified the rate and extent of change in concentration of every element in at least one plant part. Interactions of environment with developmental stage were not as evident for shoots as for the separate shoot components. Whereas other reports have often emphasized the large differences in nutrient concentrations among legume species, our data suggest that nutrient concentration may be as strongly influenced by environment as by species.     

骆驼蓬种子提取物对斜纹夜蛾的生物活性效应

用甲醇、乙醇、丙酮、氯仿、乙酸乙酯、苯、石油醚等7种溶剂对骆驼蓬种子进行冷浸提取。提取率分别为23．91％。18．68％．17．80％，18．49％，14．31％．15．13％，17．96％。7种提取物中．以种子乙醇提取物(ESPH)对斜纹夜蛾3龄幼虫的非选择性拒食活性最高。24h拒食率为70．15％。采用酸水总生物碱提取法对ESPH进行初步分离。得到氯仿、正丁醇、水及总生物碱萃取物。生物测定结果表明．总生物碱萃取物对斜纹夜蛾幼虫的生长发育抑制作用最为强烈，其次为氯仿萃取物。     

Boron Foliar Application in Nutrition and Yield of Beet and Tomato

The objective of this work was to evaluate the effect of the application of boron (B) by foliar spraying for the yield of beet (Beta vulgaris L.) and tomato (Solanum lycopersicum L.) crops. An experiment for each crop was done in a greenhouse at the São Paulo State University (UNESP), Jaboticabal campus, in Brazil. The experiments evaluated the B concentrations of 0, 0.085, 0.170, 0.255, and 0.340 g L^?1; applied in the 20, 35, and 50 days after the transplant (DAT) of beet cv. ‘Tall Top Early Wonder’, and in the 20, 40, and 60 DAT for the tomato cv. ‘Raisa N’. The plants were cultivated in pots with washed sand with 5 dm³ for the beet crop and 10 dm³ for the tomato crop. The beet and tomato crops were harvested 58 and 154 DAT, respectively. The leaves and fruits numbers; the foliar area; the dry matter of leaves, bark and roots; the fresh and dry matter of the fruits and the tuberous root; the dry matter of the total plant and the B foliar content were evaluated. The total dry matter of beet and tomato the plant were influenced by the concentration of the foliar B spray. The highest yield of the tuberous root and the total plant dry matter of beet occurred with B foliar concentration of 0.065 g L^?1 and it was associated with the B foliar content of 26 mg kg^?1. The highest yield of fruit and total plant dry matter of tomato occurred with the B foliar spraying of 0.340 g L^?1 and it was associated with the B foliar content of 72 mg kg^?1.     

Behavior of soil boron and boron uptake by M.26 apple rootstock as affected by application of different forms and nitrogen rates

Abstract

The changes in availability and uptake of boron (B) by M.26 apple rootstocks as affected by applications of different forms and rates of nitrogen (N) were examined. The study was carried out in a greenhouse using soil with low contents of organic matter, clay, calcium carbonate, NH₄‐oxalate soluble aluminum (Al) and iron (Fe), NH₂OH·HCl extractable manganese (Mn), poor cation exchange capacity and low pH. Soil N application was in the form of urea, calcium nitrate, ammonium sulphate, or ammonium nitrate at rates of 0, 17, 34, and 51 mg N kg^?1. After 1, 3, and 5 days of N application, soil B fractions were determined: B in soil solution, B specifically and non‐specifically adsorbed on soil surfaces, B occluded in Mn oxyhydroxides, and B occluded in crystalline Al and Fe oxides. The results showed that N as calcium nitrate and ammonium nitrate increased B both in soil solution and non‐specifically adsorbed on soil surface and decreased B concentration on Al and Fe oxides. This indicates that N‐NO₃ inhibited B sorption on Fe and Al oxides. Maximum B desorption from Fe and Al oxides was obtained within one day after N‐NO₃ was supplied. Nitrogen application as calcium nitrate and ammonium nitrate increased availability and uptake of B by plant roots. Thus, it was concluded that apple trees planted on coarse‐textured soils where risk of B deficiency is high, calcium nitrate or ammonium nitrates would be appropriately to apply to keep B more available.