共查询到20条相似文献，搜索用时 62 毫秒
1.
2.
不同土质中苹果幼树当年生根的解剖构造 总被引：4，自引：0，他引：4
对砂土、粘土中苹果幼树当年生根解剖构造的观察表明,砂土吸收根、生长根中柱占根面积百分比大于粘土;导管密度及导管占中柱面积百分比小于粘土;砂土输导根木质部占要面积百分比及导管总面积皆比粘土的小。 相似文献
3.
新红星与红星苹果幼树光合特性研究 总被引：1，自引：0，他引：1
采用红外线 CO_2气体分析仪、改良半叶法对新红星、红星苹果幼树新梢叶片光合特性进行比较研究,结果表明:两个品种幼树新梢叶片光合强度季节变化、日变化规律相似,均呈双峰曲线,其中日变化“午休”现象明显。年周期和日周期中,新红星苹果幼树新梢叶片的光合强度均显著地高于红星苹果幼树。与红星苹果幼树相比,新红星苹果幼树具有较高的光饱和点和较低的光补偿点,光能利用率高。整个新梢不同叶位叶片的光合强度,新红星苹果幼树均高于红星苹果幼树。与红星苹果幼树相比,新红星苹果幼树呼吸强度低、呼吸消耗少、光合强度高,能够积累较多的光合产物,有利于早果、丰产。 相似文献
4.
苹果幼树套袋防治大灰象甲效果好近几年，苹果幼树面积发展很快，春季普遍受到大灰象甲为害，严重影响了幼树生长和整形。大灰象甲属鞘翅目、象甲科，又名大灰象鼻虫。分布广，食性杂，以成虫为害寄主的幼芽、叶片和嫩茎，被啃食叶片呈圆形或半圆形的缺刻，影响苗木正常生... 相似文献
5.
6.
7.
苹果无病毒与带病毒幼树某些内含物及生育的差别 总被引：9，自引：0，他引：9
测定富士、金冠苹果无病毒幼树与带病毒幼树的某些内含物质及生长、结果情况表明,无病毒幼树比带病毒幼树的赤霉酸、吲哚乙酸、细胞激动素、核糖核酸、蛋白质等含量,有不同程度的增高。无病毒幼树较带病毒幼树长势旺,生长量大,分枝多,丰产潜力大,早期产量高。 相似文献
8.
山西省临汾市是国家农业部规划的黄土高原优质苹果优势产业区，近年来，苹果产业迅猛发展，已成为促进当地农民增收的主要经济来源之一，成为推进农村经济发展的重要支柱产业。近几年，由于冬春季气候多变，随着新栽苹果面积的不断扩大，不少果园出现苹果幼树抽条现象，特别是2013年春季苹果幼树抽条面积大、范围广、经济损失重。为了减少和预防此类问题发生，笔者对苹果幼树抽条前后的情况进行调查，并对今后新发展果园和现有幼龄果园管理提出建议。 相似文献
9.
苹果壮旺幼树不同修剪方法试验 总被引：1，自引：0，他引：1
通过稀植园和密植园苹果壮旺幼树的修剪试验，明确了长放修剪方法可节省用工，有利于树体生育，成花早，株产高，尤其适用于密植园的苹果栽培。开始采用长放修剪的树龄，密植园苹果树宜在２—３年生；稀植园苹果树宜在株间树冠相距１．５—２ｍ时进行、截放修剪方法适用于既需扩冠又要较早结果的苹果壮旺幼树。短截修剪方法修剪量大，不利于苹果壮旺幼树的生长发育，结果晚，株产低，且费工；但对栽后缓苗期树或衰弱树还是适用的。 相似文献
10.
定干后不抹芽苹果幼树生长量大苹果幼树定干后，传统习惯将整形带以下的芽子全部沫掉，结果造成载植当年形成的枝芽量少，不利于幼树快长。如果定植当年不抹芽，整形带以下的枝做为临时性辅养枝，则能大大增加幼树的枝叶量，促使幼树健壮主长。９４年我们在郭屯乡北王庄材... 相似文献
11.
The interactive effects of rooting volume and nutrient availability in a skeletal soil medium designed to meet street tree and pavement needs were observed in a containerized experiment. Benjamin fig (Ficus benjamina L.) was grown in a stone-soil blended skeletal soil material (CU-Soil™) and compared to a loam soil. The same topsoil used as the soil component in the skeletal soil material was used as the sole component in the comparison soil-only treatment.Plants grown in the skeletal soil material had reduced leaf tissue N content and depressed growth compared with plants grown in non-diluted soil. No other mineral deficiencies were found. Leaf number, chlorophyll concentration, shoot weight, and root characteristics were all affected.Reduced growth from soil dilution could be offset by the provision of an enlarged rooting volume for root development. Large containers of skeletal soil were observed to have smaller root systems compared to equivalent net volumes of loam soil at the first two harvest dates of the study. By the end of the study, the large containers of skeletal soil were observed to have developed larger root systems compared to equivalent net volumes of loam soil; resulting in comparable leaf N levels and total plant dry matter. Plants in skeletal soil had lower shoot: root ratios at the end of the study. Investing resources to further root growth in times of nutrient shortages is a probable plant reaction as evidenced by differences in specific root length between treatments. The study allowed a method for directly partitioning the containerization effect by having equivalent amounts of soil over two volumes. 相似文献
12.
Following 2 years of different soil moisture and air regimes for ‘Baccara’ roses, the optimal regimes were chosen and kept uniform for each growth medium. These regimes were implemented for an additional year (1971–1972).Soil moisture and soil air regimes employed in previous years (1969–1971) had significant after-effects on flower yields in 1971–1972, but no effect on flower quality or weight. The effect of previous suboptimal moisture and air regimes was apparently due to the number of main branches formed per plant in the initial two years, which was unaffected after implementation of optimal regimes.Approximately 4 weeks after cessation of cutting, the root system consituted 11–15% of the total weight of the plant. While 65% of the root system in non-separated beds was located in a soil layer between 30 and 60 cm, only 27% were located above this layer. 相似文献
13.
对10a生龙王帽杏园地表喷施300倍液Agri-SC土壤调理剂,研究了土壤调理剂对杏园土壤主要理化性质、微生物数量及树体根系分布的影响。结果表明,土壤调理剂不同程度降低了各土层土壤容重,增加了各土层总空隙度、田间持水量,提高了各土层碱解氮、速效磷、有机质含量,改善了土壤理化性质。土壤调理剂显著增加了细菌、固氮菌等微生物数量,增强了过氧化氢酶、蔗糖酶、蛋白酶活性,抑制了脲酶活性。促进各土层细根生长,须根数量在0～30、30～60、60～90cm土层分别是对照的2.10、1.85、1.56倍。研究结果还表明,土壤调理剂在0～60cm土层作用效果显著。 相似文献
14.
We present a simple and generalized method to predict Available Soil Water Capacity (ASWC-TOP) for a given area using a topographic index, defined as ln(/tan), where is the upslope area draining past a certain point per unit width of slope, and is the local surface slope angle. The estimated results (ASWC-TOP) were then compared with the available soil water capacity calculated from soil series information provided by Soil Conservation Service, U.S. Department of Agriculture (ASWC-SCS). The model implementation was tested with three study cases: the Seeley-Swan valley, Montana, with pixel resolutions of 100 m and 1 km, respectively; and the state of Montana, U.S.A., with a pixel resolution of 1 km. A linear relationship exists between ASWC-SCS and ln(/tan). Standard errors between ASWC-TOP and ASWC-SCS were about 4.4 cm in the Seeley-Swan valley and 5.5 cm in the state. The number of pixels with absolute residuals 4 cm between ASWC-TOP and ASWC-SCS accounted for 68.2, 64.4, and 51.9% for the valley 100 m, valley 1 km, and the state respectively. Some of the mismatches between ASWC-TOP and ASWC-SCS may indicate an improvement using this method compared to existing data because the topographic method reflects the higher spatial variation of the inputs. The increasing availability of digital elevation data, at various resolutions, may provide an alternative to soil series for estimating ASWC. The accuracy of ASWC-TOP depends on estimation of mean and maximum ASWC for a study area. 相似文献
15.
16.
内蒙古鄂尔多斯市公园绿地土壤肥力调查与评价 总被引：1，自引：0，他引：1
通过土壤样品采集和实验室分析,系统研究鄂尔多斯市公园绿地土壤的化学特性及养分丰缺状况,包括pH值、有机质、全氮、全磷以及有效氮、磷、钾,分析养分因子之间的相关性,评价公园绿地土壤的肥力状况,揭示出鄂尔多斯市公园绿地土壤存在的问题：土壤pH值偏高,其中85.7%的土壤呈强碱性,其余呈碱性;多数土壤有机质、全氮、全磷、碱解氮、有效磷、速效钾含量处于缺乏及以下水平;土壤pH值与有机质、速效钾分别显著和极显著负相关;有机质与其他养分因子之间均极显著相关。 相似文献
17.
葡萄园不同土壤管理模式对土壤理化性状及细菌群落的影响 总被引：1，自引：0，他引：1
在山东省蓬莱市瑞枫·奥塞斯葡萄基地检测了连续7年清耕、使用除草剂、自然生草、种植狗牙草和种植高羊茅对土壤理化性状和细菌群落的影响。结果表明:相比于清耕,其他4种土壤管理模式均降低了土壤容重,以种植高羊茅最为明显;除种植狗牙草显著提高土壤p H值外,其他3种土壤管理模式对土壤p H值无显著性影响;其他4种土壤管理模式均降低了土壤电导率,以自然生草最明显,降幅达48.1%;生草不同程度地提高了土壤氮磷钾和有机质含量,使用除草剂对氮磷钾含量无显著影响,而使有机质含量降低了39.6%。与清耕相比,生草和使用除草剂均增加了土壤微生物数量和群落多样性,以种植狗牙草的土壤细菌OTU数量和多样性最高;生草提高了土壤有益菌丰度,降低了有害菌丰度,总体上看以种植狗牙草效果最为突出;使用除草剂显著降低了大多数有益菌丰度。对土壤最主要的30个细菌菌落而言,不同土壤管理模式对其产生了不同影响,高羊茅和除草剂对微生物菌属的影响最接近,狗牙草对微生物菌属的影响与其他2种草差异较大。总之,生草模式优于清耕和使用除草剂,不同草种各具优势。 相似文献
18.
Agricultural soil redistribution and landscape complexity 总被引：2，自引：0，他引：2
A number of hypotheses and conceptual models, particularly those emphasizing nonlinear dynamics and self-organization, postulate increases or decreases in complexity in the evolution of drainage basins, topography, soils, ecosystems, and other earth surface systems. Accordingly, it is important to determine under what circumstances and at what scales either trend might occur. This paper is concerned with changes in soil landscape complexity due to redistribution of sediment by fluvial, aeolian, and tillage processes at historical time scales in an agricultural field system near Grifton, North Carolina. Soil mapping and soil stratigraphic investigations were used to identify and map soil changes associated with erosion and deposition by water, wind, and tillage; reconstruct the pre-agricultural soil pattern; and identify transformations between soil types. The Kolmogorov entropy of the pre- and post- agricultural landscapes was then compared. The soil transformations associated with erosion and deposition created four distinct new soils and made possible new transformations among soil series, increasing the number of soil types from seven to 11 and the number of possible transformations from 14 to 22. However, the entropy and complexity of the soil landscape decreased, with associated increases in information and redundancy. The mass redistributions created a lower-entropy landscape by concentrating particular soils and soil transformations in specific landscape settings. This result is contrary to studies showing a trend toward increasing pedological complexity at comparable spatial scales, but over much longer time scales. These results point to the importance of temporal scale, and to the fact that environmental complexity is influenced by factors other than the number of different landscape units present. 相似文献
19.
The impact of soil compaction on soil aeration and fine root density of Quercus palustris 总被引：1，自引：0，他引：1
The soil around Quercus palustris trees, 30 cm (11.8 in) average diameter breast height (DBH) were treated by compaction (C) or C plus clay slurry (CS) treatments in November 1994 and repeated in May 1996. Soil oxygen diffusion rate (ODR), fine root density (FRD), DBH, twig growth, leaf area and dieback were monitored for 4 years beginning in 1996. Both compaction treatments significantly reduced ODR at 15 cm. Early each season, ODR was below the 0.20 g/cm2/min threshold level reported to inhibit root growth in several species [Stolzy, L.H., Letey, J., 1964. Correlation of plant response to soil oxygen diffusion rates. Hilgardia 35, 567–576] for all treatments and depths. In summer each year, ODR was adequate in the shallow soils of all treatments, though often still significantly lower in compacted soils. At 30 cm, there were no consistent differences in ODR between compacted and uncompacted soil. Significant differences in FRD due to compaction treatments were inconsistent and limited to the upper 9 cm of soil in years 2 and 3. Reduced FRD in compacted soils may be a response to the reduced ODR in spring. There were no differences in DBH, twig growth, leaf area or dieback rating. Given the minimal difference in root growth, the lack of differences in top growth are understandable. This controlled study, and others preceding it, have failed to clearly show the underlying causes of tree decline and death commonly associated with soil compaction and addition of fill soil in real landscapes. 相似文献
20.
Spatial dependence and the relationship of soil organic carbon and soil moisture in the Luquillo Experimental Forest,Puerto Rico 总被引：11，自引：0，他引：11
Wang Hongqing Hall Charles A.S. Cornell Joseph D. Hall Myrna H.P. 《Landscape Ecology》2002,17(8):671-684
We used geo-spatial statistical techniques to examine the spatial variation and relationship of soil organic carbon (SOC) and soil moisture (SM) in the Luquillo Experimental Forest (LEF), Puerto Rico, in order to test the hypothesis that mountainous terrain introduces spatial autocorrelation and crosscorrelation in ecosystem and soil properties. Soil samples (n = 100) were collected from the LEF in the summer of 1998 and analyzed for SOC, SM, and bulk density (BD). A global positioning system was used to georeference the location of each sampling site. At each site, elevation, slope and aspect were recorded. We calculated the isotropic and anisotropic semivariograms of soil and topographic properties, as well as the cross-variograms between SOC and SM, and between SOC and elevation. Then we used four models (random, linear, spherical and wave/hole) to test the semi-variances of SOC, SM, BD, elevation, slope and aspect for spatial dependence. Our results indicate that all the studied properties except slope angle exhibit spatial dependence within the scale of sampling (200 – 1000 m sampling interval). The spatially structured variance (the variance due to the location of sampling sites) accounted for a large proportion of the sample variance for elevation (99%), BD (90%), SOC (68%), aspect (56%) and SM (44%). The ranges of spatial dependence (the distances within which parameters are spatially dependent) for aspect, SOC, elevation, SM, and BD were 9810 m, 3070 m, 1120 m, 930 m and 430 m, respectively. Cross correlograms indicate that SOC varies closely with elevation and SM depending on the distances between samples. The correlation can shift from positive to negative as the separation distance increases. Larger ranges of spatial dependence of SOC, aspect and elevation indicate that the distribution of SOC in the LEF is determined by a combination of biotic (e.g., litterfall) and abiotic factors (e.g., microclimate and topographic features) related to elevation and aspect. This demonstrates the importance of both elevation and topographic gradients in controlling climate, vegetation distribution and soil properties as well as the associated biogeochemical processes in the LEF.This revised version was published online in May 2005 with corrections to the Cover Date. 相似文献