共查询到20条相似文献，搜索用时 31 毫秒
1.
水肥耦合对橡胶树根系垂直分布的影响 总被引：3，自引：0，他引：3
水分和养分是限制橡胶树生长和产胶量的重要因子.以17a树龄的热研7-33-97橡胶树为试验材料,通过田间小区试验研究了不同水肥耦合水平对橡胶树根系垂直分布特征的影响,结果表明:橡胶树吸收根系主要分布在0～20 cm土层,随土壤层次的加深,橡胶根系干重在垂直分布上呈递减趋势,可用乘幂函数模型表示.适量增施氮、磷肥均能促进0～20 cm土层根系的生长；氮肥施用量过大,深层根系比重增大；轻度降低土壤水分能够促进根系扎深.水肥耦合对根系生长和分布具有调节作用,本试验条件下,各土层根系干重总量以丰氮丰水和丰磷丰水组合处理最高,分别达0.33和0.31 kg/m3,并且根系在土壤剖面上的分布与养分分布具有一致性. 相似文献
2.
玉米大豆长期轮作对土壤物理特性与水热特征的影响 总被引：2，自引：0，他引：2
合理耕层能够提高土壤应对气候变化的缓冲能力,有利于协调土壤中水、肥、气、热的关系,为作物生长发育创造适宜的水热环境。借助长期定位试验,开展了玉米连作、玉米-大豆轮作以及大豆连作等不同处理下的土壤物理性状与土壤水热特征评价。土壤采样分析与田间水热定位观测发现,玉米连作处理与玉米-大豆轮作和大豆连作处理相比,可显著降低土壤容重,增加土壤总孔隙度(P0.05),其中0~10 cm土壤层次下土壤容重分别降低12.9%和19.8%,10~20 cm层次分别低21.4%和23.2%,20~40 cm层次分别降低23.9%和29.2%,40~60 cm层次则分别降低20.3%和25.2%;玉米连作处理可显著提高5~6月份土壤水分储量,特别是0~40 cm土层下,玉米连作处理分别比玉米-大豆轮作和大豆连作处理高6.5%和6.3%、3.6%和3.4%,且差异显著,而玉米连作处理下较高的土壤水分含量有利于促进作物前期生长和后期群体质量改善;从0~30 cm土壤温度来看,不同处理间全生育期无显著差异。上述结果表明,长期玉米连作配合合理施肥可显著改善土壤结构,增加土壤水分储量,促进作物前期生长发育。 相似文献
3.
Assessment of soil enzyme activities of saline–sodic soil under drip irrigation in the Songnen plain
A field experiment was carried out to research the changes and spatial distributions of soil enzyme activities in saline–sodic soil for a different number of cultivated years under drip irrigation. The distributions of alkaline phosphatase, urease, and sucrase activities within 40 cm in both horizontal and vertical directions of the emitter in saline–sodic soils planted with Leymus chinensis for 1st, 2nd, and 3rd year were studied. A mathematical method was used to determine the relationships between soil enzyme activities and soil environmental factors contain the electrical conductivity of saturated-soil extract, pH value, available nutrient, and organic carbon. Alkaline phosphatase, urease, and sucrase activities all increased with cultivated years in saline–sodic soil under drip irrigation: from 4.5, 1.39 and 19.39 to 20.25, 3.17, and 61.33 μg g?1 h?1, respectively, after planting L. chinensis for 3 year. Alkaline phosphatase, urease, and sucrase activities all decreased with increased horizontal and vertical distance from the emitter. After 3 year of drip irrigation, the correlations between soil enzyme activities and soil environment factors had stronger correlations than in the unreclaimed land. After 4–6 years, the soil enzyme activities should attain the level of the natural L. chinensis grassland. 相似文献
4.
In sprinkler irrigated fields, irrigation water is intercepted by crop leaves. This water can be separated into several categories
depending on its movement. In this study, the categories are defined as crop stem flow water, leaf storage water, and drop
water to the soil. Crop stem flow water is especially effective for crop growth because it reaches the soil surface near the
root zone. The objective of this study is to develop a method for quantifying crop stem flow water. Field observation is conducted
to observe the movement of irrigation water droplets and to quantify the varying amounts of crop stem flow water, leaf storage
water, and drop water to the soil. The measurement of the amount of leaf storage water indicates that droplet movement on
the leaf changes constantly. To quantify three components of irrigated water, considering the continuous change of droplet
movement on the leaf surface, a simulation model is developed. The simulated amounts of crop stem flow water, leaf storage
water, drop water to the soil successfully reproduce the observed result, and model accuracy can be verified. 相似文献
5.
River water and groundwater are used to irrigate paddy fields and are also principal sources of drinking water for humans.
It is important to understand the transport characteristics of water (e.g., direction and intensity of water flow), when grasping
a pollution situation in the soil. Endo and Hara (Soc Inst Contr Eng Trans Ind App 2:88–95, 2003) developed the Quintuple-Probe Heat-Pulse (QPHP) sensor to identify water flux density vectors and thermal properties under
saturated and steady state conditions. However, there has not yet been any investigation of moisture transfer under transient
conditions such as during internal drainage and mid-summer drainage of paddy fields. Only Sand has been used in previous experiments,
and examinations with Loamy and Clayey soils have not yet led to done. Simultaneous measurements of the water flux density
vectors and thermal properties of soil texture of three types under drainage conditions as well as the soil moisture transfer
analysis with Finite Element Method (FEM), were done. The representative drainage flow was indicated as downward, except in
the Sandy-Clayey Loam, in which the rightward flux exceeded the downward flux owing to anisotropy of the soil-pore structure
and hydraulic conductivity. The apparent horizontal/vertical advanced distance was introduced in order to know about how water
moved through the soil column. The estimated volumetric water content was in good agreement with the measured value. Thus,
this measurement method was shown to be valid under transient water flow conditions. 相似文献
6.
A special compression device was devised to investigate the relation of resistivity and tightness of fiber assembly. The experimental
results show that resistivity of loose fiber assembly can reflect the tightness among fibers in fiber assembly, and also show
that tightness in cross-section horizontal to compression direction and that in cross-section vertical to compression direction
have difference. A new parameter defined as the degree of fiber orientation in loose fiber assembly is proposed to characterize
this difference. It can be expressed by that the degree of fiber orientation shows the 1/(3+C)th power dependence with respect
to the ratio of resistivity in compression direction to that in the direction vertical to compression direction. From the
experimental results, fiber orientation degree increases with increase of density of fiber assembly at the same fiber assembly
weight. It increases with the decrease of fiber assembly weight at the same density of fiber assembly. From experimental results,
parameter fiber orientation degree in loose fiber assembly and filling ratio can describe the compactness of loose fiber assembly
comprehensively. 相似文献
7.
The water balance and groundwater dynamics due to surface–groundwater interactions for watershed health assessment were investigated for the Han River basin (34,148 km2) of South Korea using the Soil and Water Assessment Tool (SWAT). The model was established considering 4 multipurpose dams and 3 multifunction weirs. The SWAT was spatially calibrated and validated using daily observed inflows for the dam (2005–2014) and weir (2012–2014) as well as evapotranspiration, soil moisture, and groundwater level data (2009–2013). The simulation results revealed the impact of surface–groundwater exchange fluxes on the water balance and baseflow by evaluating the vertical water budget and horizontal water transfer. Evapotranspiration in the surface and return flows from the shallow aquifer for the dry season was estimated to be 29 and 10% higher than for the wet season, respectively. Percolation’s role was also significant, providing approximately 24% of the annual groundwater recharge to shallow aquifers in the rainy season. On average, the February to August period (A) was characterized by a net flux of infiltration into the groundwater. For the September to January period (B), the proportion of groundwater flow into the river of the basin was nearly balanced by a slight increase in surface water infiltration. During period A of average surface water infiltration into the groundwater, the net groundwater recharge was positive and up to 20% of the infiltration during this period resulted from groundwater recharge. These results showed that groundwater recharge is strongly affected by the surface water and groundwater interactions. 相似文献
8.
深松和灌水次数对春玉米耗水特性及产量的影响 总被引：2，自引：2，他引：2
试验设置深松条件下灌水3次和4次(SI3和SI4)两个处理,以常规浅旋耕灌水3次和4次(RI3和RI4)为对照,研究深松及灌水次数对超高产春玉米生育期耗水规律、灌浆特性及产量的影响。结果表明,与常规浅旋耕相比较,深松处理可显著改善40~100 cm深层土壤水分条件,为深层根系的水分吸收提供保障,促进春玉米生长发育。深松处理较浅旋耕处理生产单位玉米平均节水量为0.149 m~3/kg,节水6.66%,单位耗水量增产量为0.322 kg/m~3,增产7.17%。相同灌水次数条件下,深松处理显著提高春玉米产量构成因素,增产达12.47%。 相似文献
9.
《Plant Production Science》2013,16(4):248-253
SummaryA non-destructive method for measurements of spatial root elongation in soil, using acoustic emission (AE) sensors, was developed. Growing roots passing in close proximity to soil particles generate AE pulses, which are detectable as counts by AE sensors. Previously, vertical maize (Zea mays L.) root elongation in soil was successfully measured using AE sensors. The method was expanded to measure spatial maize root elongation in a rectangular stainless steel container. Three AE sensors were placed vertically at 15 mm intervals on each of the four side walls of the container. Spatial root tip position was expressed by the three axes (x, y, z). Relative AE counts on the x axis and y axis (Rxp and RyP) were obtained from three sensors on the same and opposite planes as a fraction of total AE counts on both sides of this plane. RxP and RyP were linearly related to root tip positions on the x axis and y axis, respectively. The relationship was expressed by the equation : Y = 0.740 - 0.0420X (r = 0.861**) where X is the actual distance from the sensor to root tip position and Y is RxP or RyP. Spatial root tip positions can be estimated by the relative AE counts using this regressing equation. Thus, spatial root tip positions were expressed as a function of time. The trajectory of root tip position estimated by AE sensors was consistent with that obtained from actual measurements after excavation of the root from soil. This method can be used to give continuous and three-dimensional information of root tip movements, the rate and direction of root elongation. 相似文献
10.
以3种保水剂及玉米为实验材料,采用室内测定不同保水剂的吸水特性及施入保水剂后温室盆栽玉米控水的方法,研究保水剂膨胀率、吸水特性及控水过程中保水剂对土壤水分、玉米苗期株高、基径等生长特征影响。结果表明,3种保水剂溶胀度可达147.0～296.3,吸水倍数可达57.70～290.9倍;吸水速率开始较快,45min后缓慢达到平衡;使用保水剂可增加盆栽玉米土壤含水量,抑制水分的蒸发。与对照相比,施用保水剂的玉米株高增加3.89%～22.10%,玉米基径增加50.00%～79.55%,根条数及根干重均好于对照。实验结果表明,3种保水剂的施用效果为沃特新型多功能保水剂最好,汉力淼保水剂、旱宝贝保水剂次之。保水剂能有效延长玉米植株死亡时间7d以上。 相似文献
11.
生殖生长期干旱对不同耐旱型玉米自交系根系性状及产量的影响 总被引：1，自引：0，他引：1
2016～2017年,在大田微区PVC管栽条件下,采用裂区试验设计,主区为玉米自交系,裂区为水分处理,测定根系形态、根冠生长配比和产量等指标。研究结果表明,与耐旱性较弱的玉米自交系CML58相比,耐旱性较强的玉米自交系黄早四在水分胁迫后有效气生根根夹角增大明显,其根数、根长和根表面积等形态指标降幅峰值均早于CML58,40 cm以下土层的根长、根表面积和根体积降幅明显小于CML58,且0～20 cm土层的根系生长冗余在乳熟期后显著少于CML58,其根冠干重比降幅、根冠长度比和根冠面积比均高于CML58,根冠角度比较CML58小39.4%。与CML58相比,黄早四水分胁迫后能较好地调控有效气生根角度,及时调控根冠纵横生长,维持根系主要分布区结构与功能,提高深层根系分布比,减少根系生长冗余,提高物质转化效率。 相似文献
12.
The present paper reports the interaction effect of yarn twist, yarn count and number of plies on wicking behaviour of plied
cotton yarn. A three-variable factorial design technique proposed by Box & Behnken was used to investigate the combined interaction
effect of the above variables. Both the vertical as well as horizontal wicking experiments were carried out with liquids of
varying surface tensions, like distilled water, saline water and petrol. Each wick samples were subjected to nine different
types of wicking related tests. The yarn count and number of plies in the cotton wick was found to play major role in wicking
related properties, whereas the effect of twist in plied cotton wick was not that prominent when the twist per unit length
of single and plied yarns were the same and in opposite direction. The rate of vertical wicking for saline water was found
to be significantly lower than that of distilled water. The rate of horizontal wicking for distilled water was less than that
of vertical wicking of distilled water. Use two or three parallel strands instead of one resulted in marked increase of vertical
wicking. 相似文献
13.
《Field Crops Research》1995,40(2):119-127
Seasonal patterns and vertical distributions of alfalfa root systems were investigated with field experiments and a simulation model. We carried out root excavations on an established alfalfa stand at Davis, California, in 1982 and 1983. Thirty-six soil cores to a depth of 150 cm were taken seven times in 1982 and seventy-two soil cores to 30 cm were taken nine times in 1983 over the growth seasons. Live fine roots were recovered through six (in 1982) or seven (in 1983) procedures, including detailed hand sorting for removing debris. Our studies revealed that fine root mass was generally greatest in spring and fall and least during summer. Secondary minima were found within each harvest cycle. At all samplings, root mass declined exponentially with depth.A simulation model was developed for studying dynamics of alfalfa fine roots. The model has two components: root growth and death. Actual growth rate of fine roots was determined by potential growth rate and dependent on soil temperature, water and carbohydrate supply. Root death was controlled by the maximum death rate and influenced by soil temperature and nonstructural carbohydrate in roots. Through differential changes in simulated growth and death rates, the model predicted well the temporal and vertical distributions of fine root mass. A high amount of fine root mass was maintained in spring by rapid growth and moderate death rates. Frequent harvests reduced root mass in summer. Root mass increased in fall again due to a prolonged high growth rate. Sensitivity analyses indicated vertical distributions varied strongly with carbohydrate supply and soil temperature. 相似文献
14.
两种土壤质地麦田贮水量与表层土壤水分的关系 总被引：2，自引：0，他引：2
为探明不同土壤质地麦田一定深度土层土壤贮水量与表层土壤含水量的数量关系,2013-2016年度分别于粉壤土和砂壤土地块,在冬小麦生育期间通过设置不同的补灌时期和拟湿润层深度实施补充灌溉,创造不同生育时期0~200 cm土层土壤贮水量及其纵向分布的差异,分析一定深度土层土壤贮水量与表层土壤含水量的关系,建立相关方程,并对关系方程的预测精确度进行检验。结果表明,冬前期、拔节期和开花期补灌前或补灌后,粉壤土地块0~20和0~40 cm土层土壤含水量与0~100和0~200 cm土层土壤贮水量均呈极显著正相关;砂壤土地块0~20和0~40 cm土层土壤含水量与0~100 cm土层土壤贮水量呈极显著正相关,与0~200 cm土层土壤贮水量无显著线性相关关系。在粉壤土地块利用0~20和0~40 cm土层土壤含水量预测0~100和0~200 cm土层土壤贮水量,模拟效果均较好。在砂壤土地块,利用0~20和0~40 cm土层土壤含水量预测0~100 cm土层土壤贮水量,模拟效果一般或差,较难以准确预测0~200 cm土层土壤贮水量。冬小麦生长季内灌水对0~20和0~40 cm土层土壤含水量与0~100和0~200 cm土层土壤贮水量的相关性没有显著影响,但改变了数量关系方程和决定系数的大小。土壤质地对表层土壤含水量与一定深度土层土壤贮水量的相关关系影响较大,在土壤墒情预测中应区别对待。 相似文献
15.
《Plant Production Science》2013,16(3):267-276
AbstractSoil moisture distributions in rainfed lowland rice environments are largely determined by the position in the toposequence. In this study, we developed an experimental sloping bed that can simulate the soil hydrological conditions in sloping rainfed lowland rice environments to examine if the expression of promoted root system development in relation to soil moisture availability along the soil profile may maximize water uptake and dry matter production under drought. The gradient of available water along both the surface soil layer and the vertical soil profile was successfully created by manipulating ground water levels in the experimental sloping bed indicating the practical effectiveness of this experimental system. Then, two contrasting genotypes, IRAT109 (upland rice adapted japonica) and KDML105 (lowland adapted indica) were grown for plasticity evaluation. Dry matter production was maintained even at a higher position in the toposequence in IRAT109, but decreased in KDML105. Such maintenance of dry matter production in IRAT109 was attributed to its greater ability to increase root length density in a deeper soil layer, where more soil moisture is available. In contrast, KDML105 maintained root length density in the upper soil layer, and could not utilize the soil moisture available in the deeper soil layer. These results imply that the genotype that expressed root plasticity with root system developing in the soil portion where more soil moisture was available showed greater dry matter production than the genotype that showed root plasticity in the soil layer where soil moisture was less available. 相似文献
16.
橡胶园土壤中无机氮形态和含量呈现季节性的动态变化,本研究通过设置不同氮肥用量进行田间试验,分析早期施肥后橡胶园土壤中氮素运移规律。结果表明：不同施氮量土壤中矿质氮素的运移特点有所不同,但均以垂直运移为主;土壤中的铵态氮和硝态氮在不同层次的水平迁移主要在30 cm以内;各施肥处理土壤中铵态氮、硝态氮均存在明显的向下迁移,铵态氮主要迁移至40~60 cm深度,常规施肥、减量20%处理铵态氮含量分别达到209.43 mg/kg、133.32 mg/kg;硝态氮主要迁移至20~40 cm深度,常规施肥和减量20%硝态氮含量分别为127.21 mg/kg和114.29 mg/kg;不同施肥处理无机氮向下的迁移量也存在明显差异,减量40%施肥的无机氮在深层土壤中低于常规施肥和减量20%施肥处理,进一步减少了无机氮的向下淋溶损失;不同施肥处理土壤矿质氮的主要形式为铵态氮,施肥增加了硝态氮的占比,这可能与氮肥输入以及土壤pH有关。 相似文献
17.
18.
根据作物的需肥规律、土壤的供肥性能与肥料效应,配以有机肥,确定氮、磷、钾和中微量元素肥料的适宜用量和比例,既能提高肥料的利用率,获得增产,又能改善农产品的质量,提高农业经济效益、生态效益和社会效益,做到用地与养地兼顾,实现农业的可持续发展。小区试验结果显示,测土配方施肥各处理,较常规施肥增产稻谷6．8％-20．2％,增收89．2-258．4元／667m^2,土壤有机质、碱解氮、速效磷、速效钾含量均有不同程度提高。 相似文献
19.
Adequate soil water is needed for satisfactory yield and quality of potato tubers. With sprinkler irrigation systems it is common practice to apply more water than the crop uses in order to maintain high soil water levels. A study was initiated to evaluate the response of Russet Burbank potatoes to a wide range of daily sprinkler irrigation rates when grown on two soilsa loam and a sand—differing in water holding capacity. The results from the two soils were very different. On the loam soil, yields generally increased with increased applications of water, up to the equivalent of 40 to 50% estimated Et. Irrigation treatment effect on percent No. 1 tubers was inconclusive. In 1978, percent No. 1 tubers increased with water applied up to about 70% estimated Et. In 1980, irrigation rates between the equivalent of about 20 and 80% estimated Et had little effect on tuber grade. Yields and percent No. 1 tubers were depressed at irrigation rates greater than about 80% estimated Et. On the sand, yields and percent No. 1 tubers increased with increased irrigation rates up to about 100% and 80% estimated Et, respectively. Tuber specific gravity was not affected to an important degree by irrigation treatment on either soil. These results indicate that a good crop of potatoes can be grown on a loam soil at daily irrigation rates considerably less than estimated Et rates, while such reductions will decrease yields and grade on a sandy soil. 相似文献
20.
Bibalani GH Bazhrang Z Mohsenifar H Shibaei N Joodi L 《Pakistan journal of biological sciences: PJBS》2008,11(8):1126-1131
A pulling effect by side roots is one way in which roots help to side in-plane strong of a little depth soil mass. In contrast to the effect of vertically-enlarge roots, whereby soil is strengthened by an increase in its shear strength, the pulling effect strengthens the soil by increasing the tensile strength of the rooted soil zone. To verify whether or not a pulling effect exists in the root system of Prunus avium in the Roudsar, North Iran and to study the importance and size of this effect, a direct in situ test was led at a site in the Chaboksar Forests. The results from the site showed that, in the surface soil (0-30 cm), Side roots can provide a pull force of up to 490-712 N (Newtons) over a vertical cross-section area of 20-50 cm2, or an enhance in the pulling stability of the rooted soil by about 48.1%. The test results suggest that, together with the Prunus avium vertical roots, which keep the little depth rooted soil zone to the deep and more stable soil mass, the side roots of the Prunus avium, with their pulling effect, are able to make less against little depth instability in the forest slopes, such as little depth slide, to a certain degree. 相似文献