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1.
随着药品和个人护理品(Pharmaceuticals and Personal Care Products,PPCPs)生产和使用量的增加,PPCPs及其代谢产物在再生水中的检出种类、检出量不断增多,再生水灌溉可影响PPCPs在土壤-作物(蔬菜)系统中的分布及累积,但其规律及驱动机制尚不明确。为探明再生水滴灌条件下滴头布置方式对PPCPs在土壤-作物(蔬菜)系统累积的影响,该研究采用盆栽试验比较2种滴头布置方式(在番茄根部、在两番茄中间)对土壤剖面及番茄各器官中PPCPs累积量的影响,并进一步分析PPCPs在土壤-作物(蔬菜)系统累积的驱动机制。结果表明,再生水灌溉条件下不同滴头布置方式造成了PPCPs在土壤、作物(蔬菜)中累积规律的差异性,滴头布置在两番茄中间处理较其他处理而言增加了0～5cm土层吉非罗齐累积量(P0.05),降低了番茄叶部卡马西平和根部吉非罗齐的累积量(P0.05),较滴头布置在番茄根部处理降低了番茄叶部吉非罗齐和根部三氯生的累积量(P0.05);不同再生水灌溉方式通过影响土壤微环境指标导致了土壤中PPCPs分布规律的差异性,滴头布置在植株中间处理较其他处理增加了0～5 cm土层pH值,导致该土层下吉非罗齐的累积量高于其他处理(P0.05)。研究可为基于新兴污染物PPCPs防控的再生水农业安全利用提供理论依据。 相似文献
2.
通过盆栽试验 ,研究了不同管理调控措施包括施肥、灌溉、应用化学改良剂对盐渍土壤盐分分布和作物体内盐分离子吸收和分布的作用机制。结果表明 ,施用化学肥料可增大土壤电导率 ;灌水量增加可降低土壤电导率 ;施用改良剂CaSO4早期可引起土壤表层电导率升高 ,但到作物生长中、后期已与不施改良剂的相近。施肥、灌溉改善了作物生长条件 ,提高了作物的抗盐害能力。灌溉总量 375mm、三天一次的灌溉方式在降低土体盐分浓度、抑制土壤碱化方面优于两天一次的灌溉方式。大麦具有将Na 截留在茎中 ,从而减少Na 对叶片伤害的功能。大麦茎和叶中的Cl-含量都高于K 和Na 含量 ,显示较多的Cl-通过根部向地上部运输。在增加植株中K 含量、降低Na 含量 ,减轻植株盐分离子胁迫方面改良剂表现出良好的调控效果 相似文献
3.
土壤微生物量氮的动态及其生物有效性研究 总被引：38，自引：6，他引：38
采用盆栽试验和15N示踪技术对玉米生长期间不同施肥处理黑土土壤微生物量氮的动态变化及其与土壤氮素组分、玉米吸氮量之间的关系进行研究。结果表明,在玉米生长期间,施肥并没有影响土壤微生物量氮的变化趋势,但不同施肥处理土壤微生物量氮的含量明显不同。玉米植株残体的加入,增加了土壤微生物量氮的数量,降低了土壤微生物对肥料15N的释放率。土壤微生物量氮与土壤全氮含量呈极显著的正相关(r=0.727**),与土壤碱解氮及玉米吸氮量之间均呈显著正相关(相关系数分别为0.528* 和0.536*)。土壤微生物量氮和土壤氮素组分对作物吸氮量的通径分析表明,土壤微生物量氮的有效性近于土壤矿质态氮、高于土壤酸解有机氮和非酸解氮。土壤微生物量氮是作物吸收氮素的有效来源。 相似文献
4.
施肥和翻耕措施对减少水稻吸收137Cs的效应 总被引：11，自引：5，他引：6
应用盆栽试验和模拟小区试验相结合,研究增施磷肥和钾肥、土壤翻耕后对减少水稻植株(尤其是稻谷)中137Cs积累的效应.结果表明,增施钾肥可以使土壤中代换性137Cs活度明显降低,从而有效地减少水稻植株中137Cs的积累,施用量按每公顷922.5kg硫酸钾表现最好.增施磷肥的作用表现不稳定,施用量较低时表现为水稻植株中137Cs积累量减少,但磷肥施用量增高时,表现为促进作物吸收137Cs.翻耕土壤能够有效地降低水稻植株中137Cs的积累. 相似文献
5.
暗管排水条件下土壤特性和作物产量的空间变异性分析 总被引：8，自引：2，他引：8
土壤水盐及作物参数空间结构的研究是改善农田管理水平的基础。该文对暗管排水条件下玉米试验田不同深度的土壤含水率、盐碱度及作物植株高度和产量的空间结构进行了计算和分析。试验结果显示，土壤含水率的自相关距离除在0.3～0.6 m土层为20 m外，其它深度均小于5 m。土壤电导率和钠吸附比的自相关距离随土壤深度的增加而增大，但随玉米的生长而减小，一般都小于40 m。玉米植株高度、干物质量和籽粒产量的自相关距离分别为20～25，10和22～42 m。玉米高度和产量与土壤含水率正相关而与土壤含盐量负相关。土壤盐分对玉 相似文献
6.
两种除草剂的土壤生态效应及其对后茬作物生长的影响 总被引：4，自引：0，他引：4
采用盆栽试验,研究了分别施用低剂量和高剂量的苄.丁和二氯喹啉酸对水稻田土壤环境以及紫云英生长的影响。结果表明：施用除草剂苄.丁和二氯喹啉酸均不利于后茬冬季绿肥作物紫云英植株干物质的累积,而且施用量越多,干物质累积越少。低剂量的苄.丁显著降低了紫云英植株中N素累积量,而二氯喹啉酸降低紫云英植株中N和K累积量;施用高剂量苄.丁和二氯喹啉酸则降低紫云英植株中N、P和K累积量。无论是施用低剂量还是高剂量的苄.丁和二氯喹啉酸均降低土壤中N、K养分的有效性。低剂量二氯喹啉酸对土壤中有效P含量影响不显著,而施用高剂量二氯喹啉酸显著降低P素养分有效性。施用低剂量苄.丁对土壤中过氧化氢酶、蔗糖酶和尿酶活性的影响均不显著,而低剂量二氯喹啉酸则显著抑制了过氧化氢酶活性。施用高剂量苄.丁和二氯喹啉酸对土壤中蔗糖酶活性影响不显著,但均抑制了过氧化氢酶和尿酶活性。此外,施用低剂量和高剂量苄.丁增加了土壤中细菌数量,而二氯喹啉酸则正好相反。两种剂量的苄.丁和二氯喹啉酸均减少了土壤中放线菌数量,但对真菌数量变化不显著。由此可见,稻田施用二氯喹啉酸对稻田土壤环境以及后茬冬季紫云英作物的药害大于苄.丁。 相似文献
7.
长期施肥条件下旱作农田土壤水分剖面分布特征 总被引：12，自引：1，他引：12
利用黄土高原旱地长期定位施肥试验,通过比较不同施肥方式和施肥量对土壤剖面水分分布的影响,研究了施肥与土壤水分的关系,并对深层土壤水分消耗引起的水分生态效应进行了分析。试验期间,0300.cm土壤水分虽在雨季得到降水补充,但是播种期的土壤贮水量仍处于亏缺状态。结果表明,不同施肥方式和施肥量的试验处理中,100300.cm土层作物耗水剧烈,土壤水分含量均较低。与对照相比,单施磷肥对作物利用土壤水分没有显著影响;单施氮肥和氮磷配施均促进了作物对下层土壤水分的利用。在相同的施氮量下,施用磷肥加大了作物对深层土壤水分的利用,100300.cm土层的土壤含水率在磷肥用量达到45.kg/hm2后不再随施磷量的增加而降低;在同样的施磷条件下,作物对下层土壤水分的利用随施氮量的增加而增加,当施氮量增加到90.kg/hm2后,100300cm土层的土壤含水率达到一个稳定的值。在同样的氮磷用量情况下,施钾对土壤水分没有显著影响。 相似文献
8.
冬小麦/夏玉米轮作中高肥力土壤的持续供氮能力 总被引：11，自引：4，他引：11
通过连续3年的冬小麦.夏玉米轮作试验研究高肥力土壤的供氮能力。结果表明,在本试验的高肥力土壤上,存在土壤供氮能力随时间延长而下降的趋势。但在连续3年3个轮作周期6季作物生长过程中,土壤都保持了较高的供氮能力,其中夏玉米季高于冬小麦季,不施氮处理在冬小麦季的相对产量保持在46%～76%,夏玉米季为69%～81%,轮作周期中土壤氮素的表观矿化量为125～184kg.hm2,而供氮能力为123～190kg.hm2。在考虑土壤供氮能力的基础上,基于土壤植株测试的氮肥优化管理,在连续6季作物中较大幅度地降低了氮肥用量,但却获得了同传统施氮处理一致的产量,保持了较低的土壤无机氮残留量,避免了过量施氮对环境的不良影响。 相似文献
9.
长期施用磷肥对冬小麦根际磷、锌有效性及其作物磷锌营养的影响 总被引：11，自引：4，他引：11
以中国农业大学昌平试验站长期定位试验为基础,研究了长期施用磷肥对冬小麦根际磷锌有效性及其对作物磷锌营养的影响。结果表明,长期施用磷肥[P2O5,135.kg/(hm2.a)]导致土壤有效磷含量逐年提高;对根际和非根际土壤有效锌含量没有显著影响,但是根际土壤有效锌含量显著高于非根际土壤;长期施用磷肥冬小麦抽穗期植株锌含量显著低于不施磷处理;无论拔节期和抽穗期,植株含磷量和植株磷锌比(P/Zn)都随着施磷量的增加而显著增加。长期施用磷肥处理(P1和P2)在显著提高了冬小麦子粒含磷量的同时,显著降低了其含锌量;冬小麦子粒磷锌比(P/Zn)随着施磷量的增加也显著增加,子粒含磷量与含锌量呈极显著的负线性相关关系。 相似文献
10.
膜下滴灌土壤湿润区对田间棉花根系分布及植株生长的影响 总被引：9，自引：3，他引：6
滴灌条件下的土壤湿润区与作物根系分布和植株生长之间的关系是确定滴灌湿润比的理论依据。以大田膜下滴灌试验为基础,在灌水量相同的情况下,通过调控滴水流量得到不同的土壤湿润区,对不同土壤湿润区下的田间棉花根系分布及株高和叶面积生长均匀性进行了试验研究。结果表明,小的滴水流量形成窄深型土壤湿润区,其土壤水分水平分布均匀性较差,使田间棉花根系分布和植株生长均匀性低;而大的滴水流量形成宽浅型土壤湿润区,其土壤水分水平分布均匀性较好,使田间棉花根系的分布和植株生长均匀性较高;膜下滴灌条件下,宜采用宽浅型土壤湿润区。 相似文献
11.
Carmine Crecchio Maddalena Curci Patrizia Ricciuti Pacifico Ruggiero 《Soil biology & biochemistry》2007,39(6):1391-1400
Organic matter incorporation into soil can increase nutrient availability to plants but it can affect soil microbial communities. These in turn influence soil fertility and plant growth. Soil biochemical and microbiological properties are indicators of soil quality, but there is still no consensus as to how these should be used. Recent developments in molecular biology have provided new tools to obtain a view of the whole microbial community. The long-term impact of crop residue management on the microbial biomass, and on the activity and community structure of soil bacteria was evaluated in a clay soil of Southern Italy, where a monoculture of durum wheat (Triticum durum Desf.) was grown in semiarid conditions, and burning or incorporation of post harvest plant residues were typical practices. The role of N-mineral fertilization, simultaneously with the ploughing in of crop residues and during the plant growth cycle was also investigated. Total bacterial counts of viable cells, biomass C, ATP content of soil microorganisms, genetic fingerprinting of the total eubacterial community and of ammonia oxidizers were evaluated. Burning and incorporation did not affect microbial biomass C, ATP content, and total bacterial counts of viable cells although statistically relevant changes were detected among rhizosphere and bulk soil samples regardless of the crop residue management used. Molecular fingerprinting confirmed that: no significant change in the composition and diversity of total bacteria, as well as of ammonia oxidizers was induced by the crop residue managements; that soil bacteria were more sensitive to N fertilizer application during the plant growth cycle; and that rhizosphere soil samples were significantly different from those of the bulk soil. As microbiological and genetic factors related to soil fertility were not affected significantly, the long-term incorporation of crop residues, under the field conditions investigated, is a sustainable practice to manage post-harvest residues. 相似文献
12.
Background
Soil aggregation and organic carbon (OC) content are important indicators of soil quality that can be improved with plant residue amendments. The extent of the effects of plant residue amendments on soil aggregation and OC content across different plant residue and soil types is not fully understood.Aim
In this meta-analysis, we evaluated the effects of plant residue amendments on soil aggregation and OC content for different plant residues (fresh, charred) and soil types varying in clay content, initial OC content, and pH.Methods
Our meta-analysis included 50 published studies (total of 299 paired observations). We estimated the response ratios of mean weight diameter (MWD) and separate aggregate size classes, total soil OC (TSC), and aggregate-associated OC. We also considered the effect of experimental factors (study duration, residue type, residue amount, initial soil OC, clay content, and pH).Results
The benefit of plant residue amendment on soil aggregation was larger in soils with initially low OC content and neutral pH. Initial soil OC content and pH were more important than soil clay content for OC storage in soil aggregates. Both fresh and charred plant residue amendments were effective in forming aggregates, whereas charred residues were more effective in increasing TSC. We found only a weak positive relationship between the response ratio of TSC and MWD indicating that other factors besides soil aggregation contributed to the increase in soil C storage.Conclusions
While plant residue amendments can enhance soil aggregation and TSC, these effects are likely governed by the type of plant residue and soil properties such as the initial soil pH and OC content. 相似文献13.
[目的]探究马铃薯淀粉渣对土壤保肥特性及玉米幼苗生长的影响,为马铃薯淀粉渣的利用提供依据。[方法]采用室内人工气候箱模拟自然环境和用淋洗管模拟田间淋洗的方法,测定沙壤土中施入0,1.00,5.00,10.00,20.00,30.00g/kg的马铃薯淀粉渣对土壤容重、土壤总孔隙度、土壤含水量;土壤淋洗出的硝态氮、铵态氮、速效磷和速效钾含量及玉米幼苗株高、茎粗和干鲜重等指标。[结果]马铃薯淀粉渣施用量为30g/kg时,土壤容重降幅达7.24%,土壤总孔隙度、土壤含水量升幅分别为10.15%,21.25%;土壤淋洗出的硝态氮、铵态氮、速效磷和速效钾含量降幅分别为97.13%,91.03%,63.85%和66.4%;玉米幼苗株高较对照降低8.90%,茎粗较对照增加25.53%,幼苗的干、鲜重分别比对照提高13.47%,15.79%。[结论]马铃薯淀粉渣施用量为30.00g/kg时,改善了土壤理化性状,增强了保肥能力,明显促进玉米幼苗干物质的积累。 相似文献
14.
L.M.J. Verstraeten K. De Coninck K. Vlassak W. Verstraete H. Van de Werf M. Ilaiwi 《Soil biology & biochemistry》1983,15(4):397-402
The ATP content of a series of soils was investigated in relation to various soil properties. Special attention was paid to the discrepancy in ATP, as estimated after extracting with TEA/NRB and TCA. It appears that the first procedure particularly relates to active microbial cells but extracts rather poorly certain types of older microbial biomass. Nevertheless, the TEA/NRB ATP values correlate very significantly with total soil microbial biomass as determined by the CHCl3 fumigation method. In soils with active growing microbial biomass, the TEA/NRB and the TCA ATP values are about equal. In normal equilibrated soils the TEA/NRB ATP levels average about 40% of the total soil ATP levels. Finally, in densely rooted soils, the TCA ATP levels surpass largely the TEA/NRB levels, but they appear to a major extent to be due to plant cells. 相似文献
15.
The entomopathogenic fungus Beauveria bassiana infects a wide range of insects and survives as a soil saprophyte and a plant endophyte. The objective of our study was to determine the role of rainfall in dispersing B. bassiana (Balsamo) Vuillemin to the surface of corn (Zea mays) from soil with different levels of crop residue. Laboratory studies which simulated field tillage systems, had levels of crop residue which covered 0.53 (control), 34, 59 and 84% of the soil surface. Simulated rainfall in a raindrop tower at an intensity of 73 mm/h caused a significant increase in the mean number of B. bassiana colony forming units (CFU) isolated from the surface of corn plants. Plants receiving rain had a mean (±S.E.M.) of 8.8±2.8 CFU per plant; controls had a mean of 0.03±0.01 CFU per plant. The mg of soil collected from the surface of plants also was significantly influenced by rainfall. Plants receiving rain had a mean of 15.7±1.7 mg of soil per plant while controls had a mean of 3.4±0.4 mg of soil per plant. Linear regression revealed highly significant negative relationships between the mean mg of soil and the mean number of CFU per plant, over the four levels of crop residue. The amount of soil and number of CFU per plant decreased significantly with increasing levels of crop residue. In field studies with conservation- and no-till systems, results were similar to those recorded in the raindrop tower. The mean number of CFU and mg of soil per plant were both higher in conservation-till plots than in no-till plots, where surface residue averaged 45 and 95%, respectively. Rainfall plays an active role in the dispersal of B. bassiana from the soil environment to the surface of whorl-stage corn. Increased levels of crop residue reduce the amount of soil and fungal transfer to the surface of young corn. 相似文献
16.
实验研究了自然条件下原位提取的田菁(Sesbania cannabina)淋溶液和田菁秸秆模拟还田对不同类型受体植物三叶鬼针草(Bidens pilosa)、稗草(Echinochloa crusgalli)和萝卜(Raphanus sativus)的生长及土壤性质的影响,旨在从化感作用角度综合评价田菁作为绿肥栽培时的生态效应。结果表明:原位提取的田菁淋溶液和模拟还田的田菁秸秆(根、茎、叶)对发育初期的受体植物三叶鬼针草、稗草和萝卜的生长具有一定的抑制作用,尤其对于稗草的抑制效果表现最强;然而对于受体植物生长的土壤,其土壤微生物数量和土壤酶活性显著增加,此外田间野外调查进一步证实了田菁对提高土壤肥力具有显著的促进效果。因此,合理利用田菁秸秆资源不仅能抑制杂草生长,还增加了土壤酶活性和土壤微生物量,促进了土壤的代谢,显著提高了土壤肥力水平。 相似文献
17.
土层置换犁消除豆田残留除草剂药害的效果 总被引：6，自引：1，他引：5
为探索消除豆田残留除草剂对后作药害的新途径,本研究采用生物鉴定的方法,以甜菜为指示植物查明了豆田残留除草剂主要分布在0～10cm土层中,向下层逐渐减少,20cm以下土层为安全土层。自主设计的土层置换犁实现了将0～20cm土层和20～40cm土层位置转换,即所谓的土层置换。应用该犁在有残留除草剂污染的豆茬上实施土层置换改土作业后,连续2年调查作物产量结果显示,土层置换区比对照区甜菜、马铃薯等作物长势好、杂草数量少;改土后种植甜菜,第1年、第2年分别比未改土的对照增产468.9%和805.7%;种植马铃薯分别增产177.1%和31.0%;种植玉米(第2年)增产2.0%。种植连作大豆(第2年)增产6.5%。同时在未受到残留除草剂污染的土壤上实施土层置换作业后,第1年种植马铃薯和甜菜分别比对照减产3.1%和5.6%、第2年种植马铃薯和玉米,分别增产27.0%和5.2%。研究结果可为修复残留除草剂污染土壤、消除作物连作障碍和促进种植业结构提供技术支撑。 相似文献
18.
Soil carbon (C) sequestration may be a viable technology to reduce increases in greenhouse gas emissions until cleaner fuel technology is available. Crop plants with increased lignin levels may lead to increased soil C sequestration. Grain sorghum (Sorghum bicolor) exhibiting lower lignin due to the naturally occurring brown midrib mutation (bmr) may allow an assessment of the potential of biotechnology to affect soil C sequestration by manipulating plant lignin levels. A 194-d laboratory microcosm experiment was conducted to investigate the mineralization of bmr and normal plant residue from four sorghum hybrids. Cross-polarization magic angle spinning 13C-nuclear magnetic resonance of the residue agreed with chemical analysis that the bmr residue contained altered lignin and less lignin per mass weight. Ground bmr or normal grain sorghum residue was added to soil, with or without an inorganic nitrogen (N) amendment. Initial C mineralization from microcosms receiving bmr residue was higher than from microcosms receiving normal residue, but the differences were not maintained through the 194-d experiment. Total residue C mineralization was not different between bmr or normal isolines, and accounted for only 26% of the originally added residue C. Greater variability was observed between sorghum lines than between bmr or normal isolines. The addition of N to soil resulted in increased soil C mineralization. With no added N, however, microcosm C mineralization was most strongly correlated with the lignin/N ratio. With added N, microcosm C mineralization was most strongly correlated with hemicellulose content. The soil microbial community, as assessed by phospholipid and neutral-lipid fatty acid analysis, was not affected by bmr or normal genotype, but the addition of N resulted in significant changes to the soil microbial community, most notably changes to the soil fungi. Results indicate that potential does exist to modify plant residue chemistry to increase soil C sequestration, but soil fertility and microbial community dynamics are important considerations and may further enhance C sequestration potential. 相似文献
19.
通过田间调查和长期连作定点微区试验相结合,研究了长期连作棉田,集中连续使用地膜后,地膜在土壤中的累积、空间分布和形态变化,及其残膜对土壤物理性状、棉花根系生长及产量的影响。结果表明：随着地膜使用年限增加土壤中残膜平均每年以11.2 kg·hm^-2速率增加,长期连作棉田残膜主要分布在0-30 cm土层,占到了85%,在耕作层（0-30 cm）以下随着根层深度的增加,残膜量减少;大于50 cm^2残膜在土壤中平均占30%,10-50 cm^2占36.5%,小于10 cm^2占33.4%,随连作年限增加,在0-15 cm土层残膜量减少,15-30 cm土层残膜量逐渐增加,残膜破碎度提高。土壤孔隙度、田间持水量随着地膜残留量增加而增加,而土壤容重下降。棉田中残膜阻碍棉花主根垂直生长,使根系形态呈现鸡爪型和丛生型等畸形,但对棉花产量未造成影响。 相似文献
20.
Although crop residue management is known to affect near‐surface soil physical quality, little is known about the temporal variability of these indicators over short time intervals. This study evaluates the temporal changes of nine indicators of soil physical quality. These are organic carbon content, structural stability index, bulk density, macroporosity, air capacity, relative field capacity, plant available water capacity, Dexter's S‐index and saturated hydraulic conductivity. A second set of soil physical indicators, based on the distribution of soil pore volume, was also evaluated. The indicators were determined in three different times during the growing cycle of winter durum wheat cultivated within a long‐term field research carrying out in Southern Italy and comparing two types of crop residue management, that is, burning (B) and soil incorporation (I). Only the bulk density changed over time for both treatments, although the air capacity also changed for the incorporation of wheat residues. Residual effects of the autumnal soil tillage and soil compaction were a common source of variability, irrespective of which treatment was used. Based on the existing guidelines for evaluating the physical quality of these agricultural soils, optimal or near‐optimal values were detected in about half of the cases under consideration. This suggests that both B and I create sufficiently good conditions for crop growth during the crop cycle. The comparison between observed and optimal soil pore distribution function was always poor. The pore volume distributions showed lower densities of small pores and relatively higher densities of large pores than the proposed optimal distribution. This study also suggests that the considered optimal or references curves probably cannot be applied successfully to a wide range of agricultural soils. 相似文献