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华北地区小麦-玉米种植制度下硝态氮淋失量研究 总被引:10,自引:1,他引:10
应用水量平衡法计算土壤水的下渗量,通过suction cup采集土壤溶液并测定其中硝态氮含量,不同施肥处理下不同作物的硝态氮淋失量分析结果表明:2001~2002年,冬小麦生长季硝态氮的淋失损失严重,其中施N量200,400,800 kg/(hm2.a)3个施肥处理180 cm土层淋失的硝态氮量分别为0,22,110 kg/hm2。玉米生长季也存在硝态氮的淋失,上述3施肥处理180 cm层次淋失的硝态氮量分别为2,16,50 kg/hm2。 相似文献
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为了解不同氮肥用量对土壤NO3--N淋洗的风险程度, 合理指导温棚蔬菜施肥和灌溉,2005~2006年在宁夏引黄灌区滴灌条件下,以轮作体系下的温棚黄瓜-番茄为研究对象,采用田间土壤溶液定位提取、田间试验与室内分析相结合的方法,设化肥施氮量150 kg/hm2(低氮)、300 kg/hm2(中氮)、450 kg/hm2(高氮1)、600 kg/hm2(高氮2)及有机肥和不施肥(CK)处理,研究滴灌条件下施氮量对土体中NO3--N淋洗的影响.结果表明:无论是低、中或高氮处理下,黄瓜-番茄轮作周期中,滴灌施肥对0~30 cm土壤溶液NO3--N含量变化的影响明显;在高氮处理下,由于番茄季较强的滴灌量,土体中NO3--N不断向下淋洗至90 cm土层;与CK处理相比,单施有机肥会造成的土壤NO3--N向深层淋洗.因此,提出每茬蔬菜推荐施氮量控制在300 kg/hm2左右为宜,在冬春茬后期4~6月份减少滴灌次数是减少土体NO3--N向下淋洗的措施. 相似文献
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限量灌溉对石羊河流域春小麦根区水氮迁移和利用的影响 总被引:3,自引:1,他引:2
为了探讨西北旱区春小麦最佳的水氮耦合形式,在甘肃石羊河流域绿洲区进行了田间试验,研究了限量灌溉对作物根区的水氮迁移动态和利用的影响。结果表明:在春小麦拔节以前各灌水处理的根区土壤硝态氮累积主要集中在剖面0~40 cm处,其累积量都约为550 kg/hm2。播后62 d起高水处理在根区土壤硝态氮开始出现了淋失,其硝态氮累积量是特低水处理在整个剖面上累积量的0.76倍。收获时根区土壤硝态氮的残留量特低水处理>低水处理>中水处理>高水处理,其中特低水处理的残留量是高水处理的1.75倍。除拔节期以前,根区土壤硝态氮的累积量和土壤水贮量呈线性递减关系。高水处理比中水处理的产量高约4%,而灌水量比中水处理高约30%。在水资源严重亏缺的条件下,春小麦全生育期灌水360~280 mm可以保证有较高的产量和较高的水分利用效率。 相似文献
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为定量分析农田土壤水分渗漏和硝态氮淋失特征,基于3年冬小麦-夏玉米轮作水氮试验,采用Hydrus-1D模型对泾惠渠灌区农田土壤水氮运移转化过程进行动态模拟。结果表明:Hydrus-1D模型可以准确模拟不同深度土壤水分和硝态氮的运移过程,根系层下(200 cm)土壤水分渗漏量主要受灌水量影响,冬小麦全生育期根系层下土壤水分渗漏量大于夏玉米全生育期,两者渗漏量分别为15.34~25.38 cm和6.98~9.82 cm。夏玉米和冬小麦全生育期根系层下土壤水分渗漏强度分别为0.06~0.08 cm·d-1和0.06~0.10 cm·d-1,冬小麦越冬期灌溉处理的全生育期根系层下土壤水分渗漏量受越冬期灌水量影响明显。夏玉米和冬小麦生育期内根系层下硝态氮淋失通量范围分别为0.003~0.016 mg·cm-3·d-1和0.001~0.032 mg·cm-3·d-1。硝态氮淋失与灌水量、降雨量及土壤剖面硝态氮含量呈正相关关系,并且对降雨和灌溉的响应具有滞后性,约在灌水... 相似文献
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不同施肥处理对作物产量及土壤中硝态氮累积的影响 总被引:39,自引:2,他引:39
通过4a定位试验研究了小麦-玉米轮作制度下不同施肥处理对作物产量及硝态氮(NO3--N)在土壤中累积和分布的影响。结果表明:长期大量施用氮肥,会造成土壤NO3--N的累积,且土体NO3--N的含量随施氮量的增加呈直线上升趋势;在土壤空间差异不显著的情况下,NO3--N在400cm土体中的分布呈一定的规律性,分别在60cm和200cm左右存在累积峰;配合施用磷肥、钾肥可以降低土壤剖面NO3--N的含量,尤其是钾肥可显著降低土壤上层NO3--N的含量,但作物无法吸收的NO3--N却有整体下移的趋势。提出华北山前平原高水肥投入地区NPK合理施用量为:N肥200kg/(hm2·a),P肥32.5kg/(hm2·a),K肥150kg/(hm2·a)。 相似文献
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淋洗对石灰性土壤硝态氮含量及小麦吸氮量的影响 总被引:7,自引:0,他引:7
在陕西省的澄城、永寿、杨陵三地采集有机质、全氮、硝态氮含量差异较大的17个土样,分别在淋洗土壤硝态氮前、后,以小麦为供试作物,用盆栽试验研究淋洗对土壤硝态氮含量及小麦吸氮量的影响。结果表明,淋洗后土壤起始硝态氮减少了2.9%-89.6%。淋失量与硝态氮浓度有关:浓度高时,淋失量大;浓度不高时,淋失量小。与此相对应,淋洗起始硝态氮后,盆栽小麦吸氮量减少5.5%-69.8%,而且作物吸氮减少量与硝态氮淋失量密切相关(r=0.956,n=17),硝态氮淋失量可对作物吸氮减少量给出93.1%的解释。 相似文献
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施用磷肥对春小麦产量与吸氮特性及土体中硝态氮累积的影响 总被引:4,自引:0,他引:4
通过宁夏引黄灌区田间小区试验,研究施磷量分别为0、60、120、180 kg/hm2对春小麦产量、磷肥利用率、吸氮特性和土壤中硝态氮累积的不同影响,旨在明确该区合理施磷量.结果表明:合理施用磷肥(60~120 kg/hm2)能提高春小麦籽粒产量和生物量.当施磷量为120 kg/hm2,小麦籽粒产量最高,为6 215 kg/hm2.春小麦氮素累积动态呈先增加后降低的趋势,增施磷肥能增加小麦吸氮量,但到成熟期春小麦地上部氮素累积出现损失,损失量达7.7%~13.4%.当施磷量分别为60、120、180 kg/hm2时,0~150 cm土层中的NO3--N累积量分别比对照减少了50.6、58.5、62.9 kg/hm2.综合考虑磷肥利用率、小麦产量和降低土体中NO3--N残留等方面的因素,磷肥当季施用量应该控制在60~120 kg/hm2. 相似文献
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施氮对南疆潮土硝态氮分布的影响 总被引:1,自引:0,他引:1
通过田间小区试验,对南疆潮土区不施氮、优化施氮和传统施氮下棉田土壤剖面NO-3-N分布进行动态分析.结果表明:随施氮量的增加土壤剖面NO-3-N的含量和下移深度增加;优化处理和传统处理在花期均随初花期追肥、灌水发生硝态氮淋溶,优化处理淋溶到60~90 cm,传统处理由于基肥用量过大可淋溶至150~180 cm,说明基肥用量和第一次灌水是影响土壤硝态氮淋溶的主要因素.总体来说,优化处理施肥较合理,它在确保农民收益的同时能够兼顾环境. 相似文献
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本试验在片麻岩新成山地土壤上,设置0(CK)、N 120kg/hm2(N120)、N 225 kg/hm2(N225)、N 300kg/hm2(N300)4个施氮水平,布置田间微区试验,小区面积为10m2,研究了尿素不同施用量对旱地谷子生长及土壤硝态氮时空分布的影响。定位试验第二年的结果表明:在该试验条件下,N120处理谷子产量达到最高为4.76 kg/10m2,之后提高施肥量N225和N300处理的谷子产量并没有显著增加;从0~60 cm土壤剖面中硝态氮时空分布的差异可以看出:在施肥20 d后,N120、N225和N300处理NO3--N含量在0~40 cm土层显著增加,其中N225和N300处理NO3--N已经下移到40~60 cm土层。施肥80 d后,各施肥处理的硝态氮有一部分已经移出60 cm土层。到施肥96 d(谷子收获),N120、N225和N300处理比CK处理土壤剖面中NO3--N含量显著增加,且氮肥用量越高,土壤中NO3--N含量越高。 相似文献
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The nature of a reductive system which actively degrades mexacarbate in the rat intestine and liver was investigated. The system is characterized by its stability against heat and protease treatments and its requirements for a flavin cofactor and an acidic pH for a maximum activity. As a result of purification and spectroscopic identification attempts the system responsible for the above reductive activity was identified to be flavoprotein. Under anerobic conditions such flavoproteinflavin cofactor systems degrade mexacarbate first to 4-N-desmethylmexacarbate and then to polar water-soluble metabolites. 相似文献
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A whitefly (Bemisia argentifolii) resistance crisis climaxed in 1995 in Arizona cotton and prompted the development of an integrated resistance management strategy adapted from a program implemented in Israel in 1987. The strategy incorporated two new major elements: once-per-year use of the insect growth regulators (IGRs) pyriproxyfen and buprofezin, and measures to delay use of pyrethroids for as long into the growing season as possible. A three-stage chemical use recommendation was formulated comprising IGRs (Stage I), other non-pyrethroid insecticides (Stage II), and synergized pyrethroid insecticides (Stage III). Results from use of the strategy in the 1996 season were very promising. Insecticide use for control of whiteflies was reduced substantially. State-wide monitoring of whitefly susceptibility revealed significant reductions in resistance to synergized pyrethroids as well as increased susceptibility to amitraz. Susceptibility of Lygus bugs to key insecticides changed correspondingly with increases and decreases in whitefly resistance from 1994 through 1996. ©1997 SCI 相似文献
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A. D. Avgelis 《European journal of plant pathology / European Foundation for Plant Pathology》1986,92(4):147-152
Tomatoes grown in plastic houses in Crete have been inspected since 1980 for virus diseases. Plants with virus-like symptoms were checked by sap inoculation to test plants and the isolated viruses were identified by host reaction and serology. The most common viruses were, in order of frequency, tomato mosaic virus (ToMV), potato virus X, tomato bushy stunt virus (TBSV), potato virus Y and cucumber mosaic virus. The large use of ToMV-resistant cultivars reduces gradually the importance of ToMV while TBSV tends to become a serious problem of tomato in Crete.Samenvatting Van 1980–1984 werden op Kreta de in plasticfolie-kassen geteelde tomaten geïnventariseerd op de aanwezigheid van virussen. Verdachte plante werden door sapinoculatie op toetsplanten onderzocht. De daarbij geïsoleerde virussen werden daarna via de symptomen op de waardplanten en serologisch geïdentificeerd. In volgorde van belangrijkheid werden de volgende virussen het meest aangetroffen: tomatemozaïekvirus, aardappelvirus X, tomatedwerggroeivirus, aardappel Y virus en komkommermozaïekvirus, De laatste jaren is door de toenemende teelt van tomaterassen met resistentie tegen tomatemozaïekvirus het belang van dit virus sterk verminderd, terwijl het tomatedwerggroeivirus een steeds ernstiger probleem lijkt te worden. 相似文献
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T. Kapari-Isaia A. Kyriakou L. Papayiannis D. Tsaltas S. Gregoriou I. Psaltis 《Plant pathology》2008,57(2):348-353
A new laboratory technique combining shoot-tip grafting in vitro and biological indexing on indicator plants was explored for the detection of citrus exocortis and related viroids. Τhree in vitro laboratory methods were used and compared with the classical biological method. With the classical in vivo method, diagnosis is based on the expression of symptoms on indicators 11–14 weeks after inoculation. In contrast, with the first in vitro method, microindexing in vitro of citron seedlings by graft inoculation, diagnosis was possible 12 days after inoculation; with the second method, microindexing in vitro of citron cuttings by graft inoculation, 20 days after inoculation; and with the third method, microindexing in vitro of citron cuttings by injection inoculation, 40 days after inoculation. Inoculated Etrog citron plantlets grown in vitro and tested by RT-PCR showed the same viroid content as the source plants. Of the three in vitro viroid indexing methods, microindexing on cuttings by grafting was easier and more reliable than microindexing either on seedlings or on cuttings by injection. 相似文献
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A. D. Avgelis 《European journal of plant pathology / European Foundation for Plant Pathology》1987,93(4):153-158
During a survey of virus diseases affecting pepper grown in plastic houses in Crete, during 1984–1986, tomato mosaic virus (ToMV) and tobacco mosaic virus (TMV) were detected. The most common virus was TMV, being present in samples of alle pepper cultivars carrying the L1 resistance gene, while ToMV was isolated only from susceptible pepper cultivars. According to responses ofCapsicum spp. the isolates from 640 samples checked were classified into three pathotypes: P0, P1.2 and P1.2.3. Results of this study show that P1.2 represents at present the major threat to the Cretan pepper industry.Samenvatting Bij een in de jaren 1984–1986 gehouden inventarisatie van virusziekten in paprika in plastic-foliekassen op Kreta werd zowel het tabaksmozaïekvirus (TMV) als het tomatemozaïekvirus (ToMV) aangetoond. TMV kwam zeer algemeen voor: het werd aangetroffen in alle monsters van de paprikarassen met het resistentiegen L1. ToMV werd alleen geïsoleerd uit planten van vatbare paprikarassen. Volgens de waargenomen symptomen die de isolaten van 640 monsters opCapsicum spp. vertoonden, konden de isolaten in drie pathotypen, nl. P1, P1,2 en P1,2,3, worden geklassificeerd. Uit het onderzoek is gebleken dat P1,2 de belangrijkste bedreiging vormt voor de teelt van paprika op Kreta. 相似文献
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利用祁连山老虎沟地区海拔4200m气象观测站2010年的观测资料,采用FAO Penman-Monteith公式,再利用作物系数法,对高寒草甸生长季(5月22-9月22)的蒸散发量进行估算和分析。结果发现:研究期共有124天,蒸散发总量为238.3mm,日均为1.87mm·d-1。生长初期、生长中期、生长末期的蒸散发总量依次为22.6mm,179.1mm,36.6mm,依次占研究期总量的8.4%,75.2%,15.3%。5月下旬至6月中旬,日均蒸散发量以较低水平缓慢上升;6月下旬迅速增加;6月末至7月中旬猛然回落;7月中旬至8月末,日均蒸散发量迅速上升且维持在较高水平;此后直到9月22日,缓慢减少。5-9月月蒸散发总量依次为6.6mm,46.4mm,74.5mm,77.6mm,33.1mm。 相似文献