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1.
保护性耕作对农田地表径流与土壤水蚀影响的试验研究   总被引:67,自引:10,他引:57  
在黄土坡地建立天然降雨径流小区,采用翻斗式自动测试系统同步动态地监测降雨—径流的过程,试验研究了保护性耕作农田水土保持的效果和耕作、覆盖及压实3种因素对农田水土流失的影响。2年的试验表明,雨强和雨型与坡地水土流失密切相关,在暴雨情况下,由秸秆覆盖与少免耕相结合的保护性耕作具有明显的保持水土作用;采用少免耕而无秸秆覆盖配合的情况下,水土流失甚至高于传统翻耕。在试验的6种处理中,免耕覆盖不压实的保水保土效果最佳,相对传统翻耕年径流量减少52.5%,年土壤流失量减少80.2%。在覆盖、压实及耕作3因素中,秸秆覆盖对保持水土的作用最大,可减少年径流量47.3%,减少年土壤水蚀77.6%;压实次之,地表耕作的影响较小。  相似文献   

2.
旱地小麦保护性果作对土壤水分的影响   总被引:1,自引:0,他引:1  
 为检验保护性耕作技术在我国北方干旱地区的适应性,采用覆盖免耕、覆盖深松等方法,研究了保护性耕作对地表径流、水分蒸发、0~50cm土层贮水量、水分利用效率和小麦产量的影响。结果表明:保护性耕作比传统耕作径流强度减少57.3%,降雨入渗量提高98.6%,土壤蓄水量提高10.5%,蒸发量减少11.2%,供作物生长的有效水分增加19.7mm,小麦单产提高12.2%;因此,保护性耕作是北方干旱地区控制水土流失,提高小麦产量的有效耕作法,是宜于推广的一项技术措施。  相似文献   

3.
秸秆覆盖对黄土坡面矿质氮素径流流失的影响   总被引:37,自引:4,他引:33  
利用室内模拟降雨试验,研究了秸秆覆盖对坡面土壤矿质氮素径流流失和入渗的影响。结果表明:秸秆覆盖可使侵蚀量显著减少,减沙效应十分明显。由于秸秆覆盖使坡面径流流速减弱,增加了表层土壤与地表径流的作用强度,使溶解和解吸于径流中的矿质氮素含量增加,但由径流显著减少,矿质氮流失总量仍减少。与裸地相比,秸秆覆盖可显著地增加土壤水分和硝态氮的入渗深度和入渗量。  相似文献   

4.
玉米秸秆覆盖对坡面产流产沙过程的影响   总被引:15,自引:4,他引:11  
通过室内土槽模拟试验,研究不同降雨条件下玉米秸秆覆盖对沙坡地产流时间和产流产沙过程的影响。处理分为8种降雨强度和5个水平的秸秆覆盖度:0、15%、30%、60%和90%。40组模拟降雨结果表明:华北保护性耕作研究区域沙壤土条件下的产流时间与降雨强度符合幂函数关系;秸秆覆盖能延缓地表径流的产生,自然降雨(雨强10~80 mm/h)过程中,15%、30%、60%和90%秸秆覆盖较无覆盖分别推迟产流时间1.0~15.4、2.1~22.1、3.4~48.2和5.9~73.6 min;秸秆覆盖对地表径流和产沙影响显著,降雨历时1 h,30%秸秆覆盖减少径流总量17.9~/o~38.7%,减少产沙总量34.1%~48.0%0 30%秸秆覆盖水土保持效果显著,考虑到过多的秸秆覆盖(80%)会造成播种机堵塞,所以在保护性耕作研究实践中,建议保持30%~60%(1 400~3 100 kg/hm~2)的玉米秸秆覆盖,以达到较好的水土保持效果和播种质量,该研究可为保护性耕作研究区域适宜的玉米秸秆覆盖量提供依据。  相似文献   

5.
坡耕地保护性耕作措施的水土保持效应   总被引:1,自引:0,他引:1  
为探索不同保护性耕作技术在黑龙江省西部半干旱区坡耕地的水土保持效应,于2007、2008年在甘南县东兴村坡耕地径流小区进行不同耕作措施的降雨径流、土壤储水量和土壤流失量试验研究。结果表明:土壤储水量的动态变化趋势与天然降雨趋势一致;与常规耕作措施相比,所研究的3种耕作措施均可不同程度地增加土壤储水量、减少地表径流和土壤流失量,其中,垄向区田措施减少径流效果最好,覆膜+垄向区田技术集成措施增加土壤储水和减少土壤流失效果最好,免耕秸秆覆盖措施在以上3方面的效果均为最差;垄向区田和覆膜+垄向区田措施具有增加土壤储水深度的作用。研究结果可为黑龙江省西部半干旱区坡耕地水土保持措施的合理选择提供参考。  相似文献   

6.
耕作对坡耕地水土流失和冬小麦产量的影响   总被引:14,自引:5,他引:9  
在模拟降雨和自然降雨条件下研究长期(6年)定位耕作措施对豫西早区坡耕地水分保持、土壤流失以及冬小麦产量的影响。耕作措施包括少耕、免耕覆盖、深松覆盖和常规耕作。田间模拟降雨试验用来测定不同耕作措施对径流和土壤流失的影响,自然降雨小区主要用来验证模拟试验结果,同时测定不同耕作措施对冬小麦产量的影响。模拟试验结果表明:不同耕作措施下的土壤饱和导水率没有明显差异,雨前土壤含水量和降雨强度均显著影响地表径流。在试验条件下,免耕覆盖处理未产生径流和土壤流失,水土保持效果最好。与常规耕作比较,深松覆盖处理分别减少径流和土壤流失50%和90%。尽管少耕可以有效降低土壤流失,但其产生的径流量和常规耕作相近。在自然降雨条件下,免耕覆盖和深松覆盖的水土保持效果从第3年开始显著。深松覆盖在任何年型均能够显著提高冬小麦的产量。相比较常规耕作,深松覆盖平均增产9.4%。免耕覆盖除丰水年也能显著提高冬小麦产量.但增产效果不如深松覆盖显著。少耕无明显增产效果。由于产量对农民来说是评判一个耕作措施效果的重要依据,同时考虑到深松覆盖显著的水土保持效果,我们认为深松覆盖是适合当地早作农业的一个有效耕作措施。  相似文献   

7.
自然降雨条件下秸秆还田对巢湖流域旱地氮磷流失的影响   总被引:8,自引:2,他引:6  
本文通过野外径流小区观测试验,开展了自然降雨条件下秸秆覆盖对巢湖流域旱地地表径流、泥沙和氮磷流失影响的研究。试验结果表明,秸秆覆盖能有效减少地表径流量、侵蚀产沙量以及因地表径流引起的土壤氮磷流失。在整个玉米生长期间,秸秆覆盖小区的总产流量与产沙量比传统耕作小区分别减少30.47%和22.88%,表现出显著的水土保持作用。与传统耕作小区相比,秸秆覆盖小区随地表径流迁移的氮、磷流失总量分别降低27.42%和32.29%,但秸秆覆盖对径流中氮磷浓度的影响却不明显。溶解态氮是氮素流失的主要形态,颗粒态磷是磷素流失的主要形态。秸秆覆盖可以作为源头控制农业面源污染的较好措施之一加以推广。  相似文献   

8.
玉米-小麦一年两熟保护性耕作体系试验研究   总被引:64,自引:18,他引:46  
采用将夏玉米、冬小麦两季作物作为整体来研究适合华北一年两熟地区保护性耕作技术体系,确定了耕作和覆盖两个因素,包括免耕、深松、耙地、翻耕4种耕作方法,以及100%秸秆覆盖,50%秸秆覆盖和0覆盖3种秸秆覆盖水平。筛选设计了8种保护性耕作和2种传统翻耕共10种体系的试验方案。试验中测定了土壤含水量、容重、地温等参数和根系、产量等作物指标。试验结果表明,我国华北地区实施保护性耕作有利于节约用水,提高水分利用效率,增加作物产量。试验得出最适合的两种保护性耕作体系是:玉米-小麦全程免耕100%秸秆覆盖体系、玉米深松100%秸秆覆盖+小麦免耕100%秸秆覆盖体系。  相似文献   

9.
通过原位小区模拟降雨试验,研究玉米秸秆覆盖对喀斯特坡耕地产流产沙过程的影响,试验处理分为3种典型小区(上坡位、中坡位、下坡位)和4种秸秆覆盖度(0、20%、50%、80%)。试验结果表明:秸秆覆盖能显著加快地表径流产流时间,尤其在土层较厚的小区最为明显,50%秸秆覆盖度的地表径流产流时间显著提前;秸秆覆盖能显著改变径流系数大小,尤其在20%覆盖度时地表径流系数降低效果最显著,同时增加了壤中流,但具有明显的空间异质性;秸秆覆盖下地表径流和壤中流径流强度随降雨时间的变化过程均表现为先迅速增加后逐步稳定,多数情况秸秆覆盖能够有效地降低达到稳定时的地表径流强度,其中20%覆盖度时的稳定地表径流强度最小,同时秸秆覆盖对稳定壤中流径流强度影响的空间异质性较大;玉米秸秆覆盖能够有效减少喀斯特坡耕地的地表侵蚀量,在50%覆盖度时减少地表侵蚀量效果最好,且在砾石较多的小区土壤侵蚀量较小。  相似文献   

10.
李荣  侯贤清 《农业工程学报》2015,31(20):115-123
水分不足是限制旱区作物生长的主要因素,覆盖耕作能够改善土壤的微环境,从而显著提高作物的产量和水分利用效率。为探讨深松结合地表覆盖对土壤物理性状、马铃薯生长、产量及水分利用效率的影响,2013-2015年在宁南旱区采用深松覆盖秸秆、深松覆盖地膜、深松不覆盖3种覆盖耕作模式,以传统耕作不覆盖为对照,对土壤体积质量、团聚体、水分、马铃薯产量和水分利用效率等方面的影响进行了研究。结果表明,与传统耕作相比,深松结合地表覆盖可有效降低耕层土壤体积质量,改善土壤孔隙状况,以深松覆盖秸秆处理效果最佳,深松覆盖秸秆处理0~40 cm平均土壤体积质量较传统耕作降低17.1%。与传统耕作相比,深松覆盖地膜和深松覆盖秸秆处理可使0~40 cm土层0.25 mm机械稳定性团聚体数量显著增加30.7%和17.4%。深松结合不同覆盖方式能有效改善马铃薯生育期0~200 cm土层土壤水分状况,深松覆盖地膜对作物生育前期土壤水分保蓄效果较好,深松覆盖秸秆对生育中后期土壤水分状况的改善效果最佳。深松结合不同覆盖方式下马铃薯植株株高、茎粗及地上部生物量均显著高于传统耕作。作物生育前期以深松覆盖地膜处理效果最佳,中后期以深松覆盖秸秆处理促进作用明显。深松结合地表覆盖能明显提高马铃薯的产量和水分利用效率,深松覆秸秆处理的马铃薯产量、商品薯率和水分利用效率分别较传统耕作处理平均提高37.3%、93.3%和41.2%。通过两年试验研究,在宁南旱区采用深松结合地表覆盖措施具有良好的蓄水保墒效果,对马铃薯生长有利,以深松覆盖秸秆处理的增产和提高水分利用效率效果最为显著。  相似文献   

11.
低氮和干旱胁迫对富士和秦冠生长及氮素利用的影响   总被引:2,自引:2,他引:0  
【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   

12.
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   

13.
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.
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.
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   

16.
Biologically enhanced dissolution offers a method to speed removal of chlorinated solvent dense non-aqueous-phase liquid (DNAPL) sources such as tetrachloroethene (PCE) and trichoroethene (TCE) from aquifers. Bioremediation is accomplished by adding an electron donor to the source zone where fermentation to intermediates leading to acetic acid and hydrogen results. The hydrogen and possibly acetic acid are used by dehalogenating bacteria to convert PCE and TCE to ethene and hydrochloric acid. Reductive dehalogenation is thus an acid forming process, and sufficient alkalinity must be present to maintain a near neutral pH. The bicarbonate alkalinity required to maintain pH above 6.5 is a function of the electron donor: 800 mg/L of bicarbonate alkalinity is sufficient to achieve about 1.2 mM TCE dechlorination with glucose, 1.7 mM with lactate, and a much higher 3.3 mM with formate. Laboratory studies indicate that in mixed culture, formate can be used as an electron donor for complete conversion to ethene, contrary to pure cultures studies indicating it cannot. Various strategies can be used to add electron donor to an aquifer for DNAPL dehalogenation while minimizing pH problems and excessive electron donor usage, including use of injection-extraction wells, dual recirculation wells, and nested injection-extraction wells.  相似文献   

17.
李聃枫  朱春梧 《土壤》2020,52(3):561-566
自20世纪60年代"绿色革命"以来,育种技术和农耕技术的发展促进了农作物产量的大幅提升,然而作物的营养品质出现下降趋势。在相似的遗传背景下,大气CO_2浓度升高会使单位体积农作物产品的营养元素含量下降,因此"绿色革命"至今,农作物产品的营养元素下降可能受大气CO_2浓度升高影响。通过植物生长箱模拟"绿色革命"初期和目前的大气CO_2浓度水平(310μmol/mol和400μmol/mol),针对主要C_3作物水稻、小麦和大豆,研究"绿色革命"以来大气CO_2浓度升高对其籽粒的C、N、Fe、Zn元素含量的影响,结果表明:CO_2浓度升高对3种作物籽粒的C元素含量几乎没有影响,变化幅度在±1.5%之间;籽粒的N、Fe、Zn元素含量普遍呈现下降趋势,但均未达到显著水平。  相似文献   

18.
Discovery and incorporation of genes from wild species provide means to sustain crop improvement, particularly when levels of resistance in the cultigens are low and virulent strains of pests and pathogens overcome the host plant resistance. The extent of utilization and the potential of the wild genepool for genetic enhancement were reviewed in five important food crops viz. sorghum, pearl millet, chickpea, pigeonpea and groundnut grown in the semi-arid tropics. Introgression from compatible wild germplasm in the primary gene pool resulted in transfer of new cytoplasmic male sterility systems in pearl millet and pigeonpea, development of high protein, cleistogamous flower and dwarf pigeonpea lines and foliar disease resistant groundnut cultivars. Utilization of wild species in secondary and tertiary gene pools has been generally limited due to sterility, restricted recombination or cross incompatibility. Nevertheless, these species are extremely important as they contain high levels of resistance to several important biotic and abiotic stresses. Several of them, like those belonging to the Parasorghum section and the rhizomatous Arachis species are sources of multiple resistances and hold great promise to sustain crop productivity.  相似文献   

19.
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   

20.
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   

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