Organically fertilized onions (Allium cepa L.): effects of the fertilizer placement method on quercetin content and soil nitrogen dynamics

Field-cured onions cv. Hyskin ( Allium cepa L.) supplied with organic nitrogen fertilizer were studied. The fertilizer was applied by broadcasting and harrowing, broadcasting and rotary cultivation, or placement between rows. Nitrogen dynamics were monitored throughout the growing season by soil sampling. Variation in quercetin content in the onion scales was analyzed by HPLC. The organically fertilized onions were compared with inorganically fertilized onions grown in the same field. Inoculation with arbuscular mycorrhizal fungi (AMF) in the row at sowing or during commercial transplant production was tested but did not significantly affect mycorrhizal root colonization levels in the field. Onions that received no fertilizer at all or that had fertilizer placed between rows had better establishment, probably due to more favorable soil nitrogen concentrations for seedling emergence. Broadcast application led to higher nitrogen concentration in the root zone, resulting in fewer but larger individual onions. Quercetin levels were not significantly altered as a result of nitrogen fertilizer source (inorganic or organic), application method, or mycorrhizal inoculation. However, variation between years was significant, with quercetin levels in 2004 almost twice as high as those in 2005.     

Comparative studies of some phenolic compounds (quercetin, rutin, and ferulic acid) affecting hepatic fatty acid synthesis in mice

The physiological activities of some phenolic compounds affecting hepatic fatty acid synthesis in mice were compared. Male ICR mice were fed an experimental diet containing 1% quercetin dihydrate, rutin, or ferulic acid or a control diet free of phenolic compounds for 15 days. Quercetin significantly lowered serum cholesterol and phospholipid levels in mice. Also, the serum triacylglycerol level was considerably lower in mice fed the quercetin-containing diet than in those fed a diet free of phenolic compounds, although the difference was not significant. Rutin and ferulic acid did not affect these parameters. Quercetin significantly reduced the activity and mRNA levels of various enzymes involved in hepatic fatty acid synthesis. Rutin reduced a few of the parameters for lipogenesis, but ferulic acid did not affect any of the parameters. It was suggested that a reduction in hepatic lipogenesis is the mechanism underlying the hypolipidemic effect of quercetin.     

Domestic processing of onion bulbs (Allium cepa) and asparagus spears (Asparagus officinalis): effect on flavonol content and antioxidant status.

Two commonly consumed plant foods, onion bulbs and asparagus spears, were subjected to typical domestic processing, including chopping, maceration, and boiling. The impact of these processes on flavonol content was assessed. Further, the consequences of these processes on the antioxidant capacity of the tissues were evaluated with the beta-carotene bleaching method. Chopping significantly affected rutin content in asparagus, yielding an 18.5% decrease in 60 min; but in onions, quercetin 3,4'-diglucoside (Q(DG)) and quercetin 4'-glucoside (Q(MG)) were virtually unaffected by chopping. Boiling for 60 min had more severe effects, as it caused overall flavonol losses of 20.6 and 43.9% in onions and asparagus, respectively. Chopping of tissues did not considerably influence the antioxidant capacity, but boiling did provoke notable changes.     

凉州灌区酿酒葡萄氮肥施用研究

[目的]通过田间试验,研究酿酒葡萄对不同氮肥施用量及施用深度的响应,为甘肃省凉州灌区酿酒葡萄氮肥合理施用提供依据。[方法]在凉州区设置酿酒葡萄氮肥施用量及施用深度试验,研究不同氮肥施用量及施用深度对酿酒葡萄产量、收获期果实、叶片和叶柄含氮量及收获期和第2a萌芽期0—200cm土层硝态氮含量的影响。[结果]10和30cm施肥深度之间酿酒葡萄产量、收获期果实、叶片和叶柄含氮量及收获期和第2a萌芽期0—200cm土层硝态氮含量差异不显著。氮肥施用量对酿酒葡萄产量和叶柄含氮量的影响达到显著水平,对果实和叶片含氮量的影响不明显,其中高氮(300kg/hm~2)和中氮(240kg/hm~2)处理之间酿酒葡萄产量、果实含氮量、叶片含氮量、叶柄含氮量差异不明显,但是高氮和中氮处理与低氮(180kg/hm~2)处理相比,产量增加28.6%和24.1%,叶片含氮量增加17.4%和11.3%,叶柄含氮量增加了40.7%和33.0%,而对于收获期和第2a萌芽期0—200cm土层硝态氮含量,高氮处理相对于中氮和低氮处理增加了53.8%,94.4%和41.8%,76.1%,氮肥施用量和施用深度的交互效应,仅叶片含氮量达到显著水平。[结论]受土壤质地和传统沟灌影响,氮肥施用深度对酿酒葡萄影响效果不明显,240kg/hm~2为酿酒葡萄较为合适的氮肥施用量,但氮素也存在损失风险。所以,凉州灌区酿酒葡萄合理施肥应该和灌水方式进行结合来确定合理的施肥量和施肥方式。     

磷钾肥施用量和方法对弱筋小麦籽粒产量和蛋白质含量及养分吸收利用的影响

【目的】研究不同磷、钾肥施用量和施用方法对稻茬小麦籽粒产量、蛋白质含量和氮、磷、钾素吸收与利用的影响,为稻茬小麦增产增效提供参考。【方法】2020—2021年在江苏仪征市进行小麦田间试验,种植制度为稻麦轮作,供试小麦品种为弱筋型‘宁麦33’,该地块稻麦秸秆长期全部还田。试验采用裂区设计,主区为磷肥,分别设置3个一次基施磷(P) 0、72和144 kg/hm²处理(分别为P0、P1、P2)和1个基施与拔节期追施磷(P)各72 kg/hm²处理(P3);钾为副区,设置3个一次基施钾(K) 0、72和144 kg/hm²处理(K0、K1、K2)和1个基施与拔节期施钾(K)各72 kg/hm²处理(K3)。小麦收获后,调查生物量与籽粒产量,分析植株和籽粒中氮磷钾含量和籽粒蛋白质含量。【结果】施磷、钾肥对植株氮、磷、钾养分积累量、养分利用效率、籽粒产量和蛋白质含量有显著效应和交互效应,适量的磷、钾肥(72 kg/hm²)配施有助于量质效协同提升,而过量施用(144kg/hm^2<...     

The effect of composted municipal waste,sheep manure,and urea nitrogen on the growth and chemical composition of two rapeseed cultivars

Oil cultivars of Brassica napus L. were grown to compare the effects of composted municipal waste (CMW) and sheep manure (SM) to field soil (C0). To each soil group, one of three levels of urea nitrogen fertilizer (N) was added. SM grown plants had higher N than those grown in CMW with the Sarigol cultivar having a higher N content than the RGS cultivar. Field soil plants grown in control soil had lowest N levels. Organic amendments increased N content of both cultivars. SM grown plants produced more siliques, a higher seed yield, and greater 100 seed weight compared to those grown in CMW. Control soil plants had the lowest number of siliques, seed yield, and 100 seed weight. CMW-treated plants contained slightly more metals than SM plants. Field soil plants had the lowest metal levels. CMW and SM application had potential to improve the growth and chemical composition without adding urea.     

Effects of bark mulch and npk fertilizer on yield,leaf nutrient status and soil mineral nitrogen during three years of strawberry production

The effects of bark mulch and NPK fertilizers on yield and leaf and soil nutrient status of ‘Korona’ strawberry plants (Fragaria×ananassa Duch.), were studied over a period of three years. A significant effect of mulching was found in the first harvest year, but additional fertilizer did not affect total yield. Bark mulch slightly decreased the level of leaf nitrogen, but increased the level of leaf phosphorus and potassium in all years. Bark had a significant, negative effect on soil nitrate and ammonium content in the two first seasons. Mulching increased the soil moisture content in all years.     

Natural compounds derived from foods modulate nitric oxide production and oxidative status in epithelial lung cells

The effects of natural antioxidants on nitric oxide (NO) modulation and oxidative status were determined in rat epithelial lung cells (L-2). Cells were stimulated with cytokines and treated with one of the following: resveratrol, soybean saponin group B (SSB), quercetin, genistein, olive leaf polyphenol concentrate (OLPC), or N-acetyl-L-cystein (NAC). NAC had no effect on NO levels, whereas resveratrol and OLPC were found to be effective in reducing nitrite levels, modifying iNOS mRNA, and decreasing free radical production. OLPC affected the levels of MnSOD while resveratrol did not, indicating that they act via different pathways. Quercetin and genistein reduced nitrite levels without affecting iNOS levels, presumably by scavenging NO. SSB did not affect nitrite levels, but exposure did reduce iNOS mRNA expression and protein levels, possibly due to antioxidant activity. Naturally occurring antioxidants, in particular resveratrol and OLPC, may have therapeutic potential in the treatment of inflammatory diseases.     

不同土壤肥力水平下施氮对甘薯产量与氮肥利用率的影响

为探明不同土壤肥力条件下施用氮肥对甘薯产量和氮肥利用率的影响,选取鲜食型甘薯品种烟薯25号为试验材料,采用大田试验,研究了施氮对不同土壤肥力下甘薯产量及产量构成因素、干物质积累规律和氮肥利用率的影响。结果表明:不施氮条件下,甘薯蔓数、最大蔓长度、叶面积指数和产量均表现为高肥力中肥力低肥力(P0.05)。3种土壤肥力条件下,增施氮肥均能显著增加甘薯蔓数、最大蔓长度和叶面积指数(P0.05),但对最大蔓节间数影响不显著。高肥力、中肥力和低肥力地块分别在施氮量为50,100,150kg/hm~2时获得最高产量,分别较不施氮处理(N0)增产16.06%,29.63%和33.33%。与地力条件无关,增施氮肥均能提高甘薯地上部干物质累积量。中、低土壤肥力条件下,甘薯氮累积量随施氮量增加逐渐增加,而高土壤肥力条件下呈先增加后降低的趋势;高肥力地块氮肥利用率随施氮量增加而逐渐降低,中肥力地块先增加后逐渐降低,在100kg/hm~2时氮肥利用率最高,低肥力地块逐渐增加。综合产量和氮肥利用率,可知高肥力、中肥力和低肥力地块甘薯适宜施氮量分别为50,100,150kg/hm~2。     

Effects of Nitrogen Fertilizer on Protein Quantity and Gluten Strength Parameters in Durum Wheat (Triticum turgidum L. var. durum) Cultivars of Variable Gluten Strength

Field studies were conducted over three years at two locations in Saskatchewan, Canada, to determine the effect of nitrogen fertilizer on protein quantity and protein strength in 10 cultivars of durum wheat (Triticum turgidum L. var. durum) representing a range of gluten strength. Increasing nitrogen fertilizer resulted in increased protein content in all cultivars across environments. Cultivars were clearly differentiated on the basis of gluten strength using a gluten index (GI), SDS sedimentation (SDSS), alveograph indices of overpressure (P) and deformation energy (W), mixograph energy to peak (ETP), and mixograph bandwidth energy (BWE) at all fertilizer levels. Variable cultivar response to nitrogen fertilizer was observed only for protein content, GI, and alveograph W. The nature of the cultivar‐by‐fertilizer interaction for GI suggested that the conventional strength cultivars would benefit more from nitrogen fertilizer than the extra‐strong types, which showed no change or slight decreases in GI with nitrogen fertilizer despite an increase in total gluten. SDSS increased with nitrogen fertilizer, following similar trends as protein. Gluten strength rankings of the cultivars by SDSS were maintained with increased fertilizer. Fertilizer had little effect on alveograph P, mixograph ETP, and mixograph BWE. Overall, GI values were more stable across increasing levels of nitrogen fertilizer and resultant increased protein content compared with SDSS, mixograph development time, and alveograph W and L, suggesting it is a good test for estimating intrinsic gluten strength for cultivars with a wide range of protein content.     

Effects of irrigation volumes and organic fertilizers on eggplant grown in Mediterranean environment

A three-year field experiment was carried out in Mediterranean conditions to study the effects of different irrigations and organic fertilizers on yield, quality and nitrogen utilization of eggplant crop and on soil properties. In a split-plot design, two irrigation treatments (re-establishing 100% and 50% of the calculated maximum evapotranspiration) and four fertilizer treatments (mineral fertilizer, commercial stable manure, anaerobic digestate and municipal solid waste compost) were compared. The highest water volume increased significantly the total and marketable yield, the number of marketable fruits, the dry matter of fruits and the nitrogen-use efficiency with respect to the treatment with the lowest irrigation. Nevertheless, the same treatment decreased significantly the fruit dry matter percentage and total soluble solid content. The lowest water volume led to an improvement of fruit quality. Anaerobic digestate increased significantly the total and marketable yield and dry matter compared with compost. Harvest index, nitrogen harvest index, pH, acidity and total soluble solids did not show significant differences among all fertilizer treatments. N translocation ability of plants and fruit quality were not influenced by the type of fertilizer. At the end of experiment, anaerobic digestate and compost reached the highest levels of soil total organic carbon and humic and fulvic acids content. Besides, anaerobic digestate increased the total extractable carbon, phosphorus and nitrogen content compared to all other treatments. Soil copper, nickel and lead content in all treatments enhanced compared to that at the beginning of experiment, but this accumulation did not represent a possible environmental risk. The content of heavy metals in the soil, after 3 years of application, did not exceed the limits imposed by the Italian law. This study showed that the organic wastes, after being adequately processed, could be applied successfully in agriculture especially in arid environments, characterized by quick mineralization and very low organic matter content.     

Phosphorus source effects on alfalfa yield,total nitrogen content,and soil test phosphorus

Abstract

Recent studies showing a lack of response by alfalfa (Medicago sativa L.) to phosphorus (P) fertilization have raised concerns about the efficacy of commonly used P fertilizer materials in the southwestern United States. Studies were conducted between 1982 and 1985 in southeastern New Mexico to evaluate (i) alfalfa yield response to different P sources, (ii) the effect of P fertilizer source on forage total nitrogen (N) content and leafiness, and (iii) the effect of P fertilizer source on soil test P. Nine P sources were applied annually from 1982 through 1984 at a rate of 58 kg P/ha. Alfalfa was grown during 1985 without fertilization to examine the residual effect of P sources. Triple superphosphate (TSP) and monoammonium phosphate (MAP) gave the highest alfalfa forage yields over the 3‐year application period, but no residual fertilizer effects were observed when fertilization was discontinued. Fertilization did not affect forage leafiness. Except for a small N response in forage total N content in 1984, neither P nor concomitant applied N had a significant effect on forage N content over the 3‐year period. Phosphorus fertilization significantly increased average soil test P for the 3‐year period, but there were no significant differences between treatments. Currently used P materials (TSP and MAP) still appear to be the most efficacious for alfalfa production.     

补充灌溉、氮素营养与秸秆覆盖对冬小麦生长及产量的影响研究

大田试验研究补充灌水、施N肥与秸秆覆盖对冬小麦根系和地上部生长、产量及其构成因子的影响结果表明 ,施N肥对冬小麦生长发育和产量的效应最明显 ,单独覆盖秸秆或补充灌水基本无效甚至出现副作用。施用N肥和秸秆覆盖可促进冬小麦根系发育和地上部生物量累积。肥料供应充足时覆盖秸秆对冬小麦根系的作用与水分状况有关 ,土壤水分胁迫下秸秆覆盖效果不明显 ,此时施用N肥甚至出现一定负效应。水分充足与否 ,施N肥和秸秆覆盖均对冬小麦产量的形成有一定协同效应 ,补充灌溉与施用N肥和秸秆覆盖配合处理小麦产量最高。     

Onions: a source of unique dietary flavonoids

Onion bulbs (Allium cepa L.) are among the richest sources of dietary flavonoids and contribute to a large extent to the overall intake of flavonoids. This review includes a compilation of the existing qualitative and quantitative information about flavonoids reported to occur in onion bulbs, including NMR spectroscopic evidence used for structural characterization. In addition, a summary is given to index onion cultivars according to their content of flavonoids measured as quercetin. Only compounds belonging to the flavonols, the anthocyanins, and the dihydroflavonols have been reported to occur in onion bulbs. Yellow onions contain 270-1187 mg of flavonols per kilogram of fresh weight (FW), whereas red onions contain 415-1917 mg of flavonols per kilogram of FW. Flavonols are the predominant pigments of onions. At least 25 different flavonols have been characterized, and quercetin derivatives are the most important ones in all onion cultivars. Their glycosyl moieties are almost exclusively glucose, which is mainly attached to the 4', 3, and/or 7-positions of the aglycones. Quercetin 4'-glucoside and quercetin 3,4'-diglucoside are in most cases reported as the main flavonols in recent literature. Analogous derivatives of kaempferol and isorhamnetin have been identified as minor pigments. Recent reports indicate that the outer dry layers of onion bulbs contain oligomeric structures of quercetin in addition to condensation products of quercetin and protocatechuic acid. The anthocyanins of red onions are mainly cyanidin glucosides acylated with malonic acid or nonacylated. Some of these pigments facilitate unique structural features like 4'-glycosylation and unusual substitution patterns of sugar moieties. Altogether at least 25 different anthocyanins have been reported from red onions, including two novel 5-carboxypyranocyanidin-derivatives. The quantitative content of anthocyanins in some red onion cultivars has been reported to be approximately 10% of the total flavonoid content or 39-240 mg kg (-1) FW. The dihydroflavonol taxifolin and its 3-, 7-, and 4'-glucosides have been identified in onions. Although the structural diversity of dihydroflavonols characterized from onions is restricted compared with the wide structural assortment of flavonols and anthocyanins identified, they may occur at high concentrations in some cultivars. From bulbs of the cultivar "Tropea", 5.9 mg of taxifolin 7-glucoside and 98.1 mg of taxifolin have been isolated per kilogram of FW.     

减氮条件下生物质炭施用对珠三角地区生菜产量、品质及土壤性质的影响

生物质炭(biochar,BC)施用具有改良土壤、提高作物产量等效应。本文探究了生菜产量、品质和土壤性质等对化肥氮(N)减施和生物质炭施用1年后的响应，以期为珠三角地区露地蔬菜生产中化肥合理减量和生物质炭科学施用提供依据。通过在佛山市三水区开展田间小区试验，观测了常规施氮(N100%)、减氮20%(N80%)、减氮40%(N60%)、减氮40%+生物质炭10 t/hm²(N60%+BC10)和减氮40%+生物质炭20 t/hm²(N60%+BC20)处理下生菜产量、品质、叶片SPAD值及土壤养分等指标的变化。结果表明：(1)较N100%处理，N60%处理生菜产量显著降低13.5%。减氮40%条件下，配施10～20 t/hm²生物质炭可提高生菜产量9.5%～22.7%，与N100%处理产量相当，说明生物质炭施用对生菜产量具有显著提升效果。(2)氮肥减量和生物质炭施用对生菜单株鲜重、直径和水分含量等均无显著影响，而对叶片SPAD值在不同生育期有不同影响。减氮条件下施用生物质炭处理生菜的氮和磷吸收量提高，是其增产机理之一。(3...     

Sesame (Sesame indicum L.) biochemical and physiological responses as affected by applying chemical,biological, and nano-fertilizers in field water stress conditions

Abstract

Co-application of nano, chemical, and biological fertilizers has been recommended to increase quality and quantity of plants in sustainable production systems. Field experiments (factorial split plot experiment based on completely randomized block design) were conducted during two consecutive years to investigate the effect of nitrogen (nitroxin, urea, and nitroxin + 50% urea) and potassium (without fertilizer, soil and foliar application of potassium nano-chelate, and potassium dioxide) forms on grain yield, physiological traits, oil content, and fatty acids composition of sesame under water stress conditions (normal irrigation, irrigation up to 50% seed ripening and flowering (mild and severe stresses, respectively). Severe water stress was caused decreasing chlorophyll content, grain yield (25.4%), seed oil content (2.87%), and unsaturated fatty acid content, while it increased catalase and peroxidase activities, total carbohydrate, and saturated fatty acids content in compared to the control. As shown, the grain yield in the second year was more than the amount in the first year. The highest grain yield was achieved in co-application of 50% urea and nitroxin in combined with potassium dioxide under normal irrigation during the second year, which showed an increase of 42%, compared to the control treatment. Application of potassium fertilizer (nano or chemical) increased unsaturated fatty acids content in compared to the control treatment. While non-application of fertilizer had the highest saturated fatty acids content. Finally, the co-application of potassium fertilizer (nano or chemical forms) with nitrogen fertilizer (nitroxin + 50% urea) could alleviate the adverse effects of water stress on the studied traits.     

硅对大葱矿质元素吸收、 分配特性及产量和品质的影响

【目的】大葱因含有机硫化合物等功效成分而具有重要的保健和药用价值,为此,前人曾就氮、 磷、 钾、 硫等矿质元素与大葱产量、 品质及风味物质的关系进行了一些研究。硅作为一种公认的有益元素,在提高作物产量、 改善品质等方面具有重要作用,本试验研究了硅对大葱矿质元素吸收、 分配特性和产量及品质的影响,以期为大葱高效施肥提供科学依据。【方法】本研究以‘天光’和‘章丘’两个不同类型大葱品种为试材,供试硅源均为Na2SiO3·9H2O,通过盆栽Hoagland营养液培养和大田土壤栽培相结合的方法,分别研究了营养液不同硅水平(SiO2 0、 0.6、 1.2、 1.8 mmol/L)和土壤不同施硅量(SiO2 0、 150、 300、 450 kg/hm2)对大葱生长、 产量、 品质及硅、 氮、 磷、 钾含量、 吸收量的影响。【结果】营养液硅水平在1.8 mmol/L范围内,‘天光’和‘章丘’两品种大葱株高、 假茎长、 假茎粗、 植株干重以及单株产量均随硅浓度升高呈先上升后下降的趋势,且均以1.2 mmol/L的处理表现最好,其单株产量分别较不施硅提高了19.4%和30.9%; 适量施硅还显著提高了大葱游离氨基酸、 可溶性糖、 丙酮酸等含量,表明施硅有利于改善大葱品质。随营养液硅水平的升高,两大葱品种各器官硅含量均显著增加,在1.8 mmol/L处理时达最高,而钾含量则与之相反,氮、 磷含量则呈先上升后下降的趋势,均以1.2 mmol/L处理含量较高; 由于施硅促进了大葱生长,所以大葱对硅及氮、 磷、 钾的吸收量则均随硅水平的升高呈增加趋势。大田施硅试验表明,‘天光’和‘章丘’两品种大葱均以施硅量(SiO2)300 kg/hm2时产量较高,分别比对照增产15.4%和25.6%。【结论】大葱增施硅可显著增加大葱对硅及氮、 磷、 钾的吸收量,促进植株生长,提高产量和品质,但同一硅水平的增产率以‘章丘’品种显著高于‘天光’,且二者随硅水平变化的幅度也不相同,表明不同大葱品种对硅的反应敏感性存在显著差异。本试验条件下,以营养液硅水平1.2 mmol/L、 土壤施硅300 kg/hm2时较有利于大葱的生长及产量和品质的提高。     

Quercetin and its in vivo metabolites inhibit neutrophil-mediated low-density lipoprotein oxidation

This study examined the effects of metabolic transformation of the common dietary flavonoid, quercetin, on its ability to protect low-density lipoprotein (LDL) from neutrophil-mediated modification. Quercetin was shown to be effective in protecting LDL against neutrophil-mediated modification at physiological concentrations (1 microM) and appears to act by inhibiting myeloperoxidase (MPO)-catalyzed oxidation (IC(50) = 1.0 microM). Quercetin was also shown to protect against radical-induced [2,2'-azobis(2-methylpropionamidine)dihydrochloride] oxidation (IC(50) = 1.5 microM). Studies of structure-activity relationships showed that methylation at the 3'-position or glucuronidation at the 3-position did not significantly affect inhibition by quercetin of the MPO activity, but conjugations at both positions significantly reduce its activity. Our results suggest that the common dietary flavonoid, quercetin, and some of its major in vivo metabolites are potential inhibitors of MPO at physiological concentrations. Dietary flavonoids that could modify MPO activity could protect lipoproteins from damage in chronic inflammatory states such as cardiovascular disease.     

INFLUENCE OF ORGANIC AND MINERAL FERTILIZATION ON GERMINATION,LEAF NITROGEN,NITRATE ACCUMULATION AND YIELD OF VEGETABLE AMARANTH

The influence of manure and diammonium phosphate (DAP) mineral fertilizer on germination, leaf nitrogen content, nitrate accumulation and yield of vegetable amaranth (Amaranthus hypochondriacus) was investigated. Field trials were set up at the University of Nairobi Field Station at the Upper Kabete Campus during the long rains of March–May in 2007 and 2008. Trials were laid out as complete randomized block design with four fertilization treatments: 20, 40, and 60 kg nitrogen (N) ha^?1 supplied by DAP (18:46:0), 40 kg N ha^?1 supplied by cattle manure and an unfertilized control variant. The vegetables were harvested at three maturity stages at 6, 7, and 8 weeks after planting. Results indicated that there were significant differences between treatments in germination percentage, leaf nitrogen content, nitrate accumulation and vegetable yield. Plants that received manure had a higher germination percentage than those that received the same amount of N supplied by the chemical fertilizer DAP. The yields generally increased from week 6 to week 8. The highest yield was recorded in plots receiving 40 kg N ha^?1 from DAP at eight weeks after planting. Plots that were supplied with manure recorded the lowest yield when compared to the fertilizer treated plots at all rates. Leaf nitrogen content increased with increasing rate of N but only when N was supplied by DAP fertilizer. The leaf nitrogen content decreased with increasing age of the plants. The leaf nitrate content increased with increase in DAP application rate. Results indicate that manure application produced quality vegetables in terms of low nitrate levels, but leaf nitrogen and vegetable yields were low. DAP application effected higher yields, but the vegetables had high though acceptable nitrate levels.     

好氧发酵猪粪部分替代化肥提高夏玉米氮素利用率和土壤肥力

  【目的】  化肥及畜禽粪便的不合理施用不仅影响作物增产,还严重威胁土壤健康和环境安全。探究不同发酵方式猪粪有机肥及有机肥替代化肥的比例对夏玉米氮素吸收及土壤碳、氮含量的影响,为规模化养猪场粪便快速处理,及制定其与化肥的适宜配比提供理论依据。  【方法】  以‘先玉335’为供试材料,在中国农业大学丰宁动物试验基地进行田间试验。设置5个处理:不施肥 (CK),100%化肥氮 (CF),100%自然堆肥猪粪氮 (PM),100%好氧发酵猪粪氮 (PC),50%好氧发酵猪粪氮 + 50%化肥氮 (FM)。分析猪粪不同发酵方式及有机氮替代比例对夏玉米氮素吸收及土壤碳氮的影响。  【结果】  在等氮条件下,与CF处理相比,FM处理产量、穗粒数、千粒重均以FM处理最高,其中FM处理显著增产13.2%,PC、PM处理与CF处理差异均不显著。FM处理玉米氮素积累量最高,两年平均为304.6 kg/hm2,较CF处理氮素累积量显著提高15.5%;PC、PM处理与CF处理氮素积累量差异不显著。与CF 处理相比,FM处理的氮素当季回收率、氮素农学利用率和偏生产力两年平均分别显著提高85.9%、59.5%和13.2% (P < 0.05),PC、PM处理与CF 处理之间无显著差异。在玉米拔节期和抽穗期,FM处理0—40 cm土壤无机氮含量均最高,与 CF 无显著差异;在成熟期,FM处理土壤无机氮含量较CF处理显著增加41.8%,而PC和PM处理与CF处理无显著差异。此外,施用有机肥可不同程度地增加土壤有机碳和全氮含量,与CF处理相比,PC和FM处理使有机碳含量分别显著提高13.3%和9.8%;FM处理土壤全氮含量显著提高33.4%。  【结论】  在等氮条件下与单施化肥相比,50%好氧发酵猪粪氮 + 50%化肥氮配施不仅显著提高了夏玉米产量和氮素累积吸收量,还提升了土壤全氮和有机碳含量以及0—40 cm土层土壤无机氮含量。单独施用自然堆肥、好氧发酵猪粪及化肥在产量和氮素积累方面没有显著差异,但可增加土壤全氮和有机碳含量,有利于土壤培肥,而施用好氧发酵猪粪的效果又优于施用自然堆肥。