ISWC OpenIR  > 水保所知识产出(1956---)
黄土区土壤水分对典型植物有效性的研究
吴元芝
Subtype博士
2010-11
Degree Grantor中国科学院研究生院
Place of Conferral北京
Keyword土壤含水量 水分有效性 土壤质地 大气蒸发力
Abstract

黄土高原地区水资源匮乏,气候暖干化背景下土壤干燥化不断加剧,生态和农业
可持续发展都面临严峻挑战。研究不同土壤质地、植物及气象条件下土壤水分有效性
对黄土高原植被恢复和发展旱地农业具有指导意义。本文选取3 种代表性土壤、2 种
代表性作物和一种常见造林树种进行盆栽及田间小区的控水试验,观测不同水分处理
条件下植物的生长、蒸腾和光合等生理参数的变化,系统分析了不同土壤、气象和植
物条件下的土壤水分有效性,并借助Hydrus-1D 模型从理论上探讨了不同因子对植物
水分有效性的影响。取得如下结论:
(1)比较了盆栽和田间小区试验作物生长和蒸腾对水分亏缺的响应,发现:盆
栽玉米和小麦的绝对生长量和蒸腾量明显低于田间小区,但是盆栽和田间小区作物的
相对生长和相对蒸腾随土壤含水量的动态变化没有明显差异。
(2)分析了不同生理指标评价土壤水分有效性的差异,发现:不同指标随土壤
含水量的动态变化具有一致的规律,即都存在阈值反应。不同指标的土壤水分阈值不
同,瞬时指标的水分阈值低于日指标和生育期指标,与生长有关的指标的水分阈值低
于与蒸腾有关的指标,灌浆前日蒸腾的水分阈值高于灌浆后日蒸腾,而灌浆前后生长
指标的土壤水分阈值差异不明显。
(3)研究了不同质地、不同植物土壤水分有效性的差异,发现:玉米各项生理
指标的土壤水分阈值塿土最高、黑垆土和黄绵土相近,在田间稳定湿度附近,土壤水
分有效性黑垆土>黄绵土>塿土;小麦各项植物指标的土壤水分阈值黄绵土最高、塿
土居中、黑垆土最低,在田间稳定湿度附近,土壤水分有效性黑垆土>塿土>黄绵土;
刺槐各项指标的土壤水分阈值塿土最高、黄绵土居中、黑垆土最低,在田间稳定湿度
附近土壤水分有效性,塿土>黑垆土>黄绵土。
(4)分析气象因子对土壤水分有效性的影响,发现:塿土的水分有效性在高温
时不受湿度影响,在低温时随湿度升高而降低;黄绵土的植物水分有效性在高温时随湿度升高而升高,在低温时随湿度升高而降低;玉米3 种土壤的盆栽试验中土壤水分
阈值随大气蒸发力虽有升高但升高不明显;小麦3 种土壤试验中土壤水分阈值随大气
蒸发力的升高而升高,且ET0 > 3.0 mm d-1 时土壤水分阈值有明显升高;刺槐3 种土
壤试验中黄绵土的土壤水分阈值在ET0 > 3.0 mm d-1 时明显升高,塿土和黑垆土的水
分阈值随大气蒸发力的升高反而明显降低。
(5)利用Hydrus-1D 模型模拟土壤水分有效性动态变化过程及其影响因素,发
现:大气蒸发力和叶面积指数对土壤水分有效性动态变化曲线的形状没有明显影响,
对土壤水分阈值略有影响;而根系深度和根系分布形状不仅对土壤水分有效性动态变
化曲线的形状有影响,而且对土壤水分阈值影响的也很大;3 种土壤以绝对含水量表
示的水分阈值大小顺序是塿土>黑垆土>黄绵土;根系吸水速率的土壤水分阈值随着
大气蒸发力的升高而升高,但还受其叶面积指数、根系深度和根系分布影响;在冠层
郁闭前后土壤水分阈值随叶面积指数的变化不同;随着根系深度和深层根系分布的增
加土壤水分阈值降低,但是在黄绵土中降低程度小于塿土和黑垆土。
本研究结果表明,利用归一化植物生理指标研究盆栽试验中土壤水分对作物的有
效性可以应用到田间,评价土壤水分有效性的结果会因所用指标的时间尺度、生育期
及涉及生理过程不同而有差异,土壤水分有效性是土壤质地、气象条件和植物生长状
况等因素综合影响下植物对土壤水分变化的响应。
关键词:土壤含水量,水分有效性,土壤质地,大气蒸发力

Other Abstract

Water resources shortage is very severe in the Loess Plateau of China. The climate
warming and drying in this area is leading to a further decline of soil water reserve, which
challenges the ecological and agricultural sustainable development. Studying on the
dynamics of soil water availability for different plants in different textured soils, and under
different weather conditions could guide for the vegetation restoration and the
development of the dryland farming. In this study, three typical textured soils (loamy clay,
clay loam and sandy loam) collected from different area in the Loess Plateau were selected
for growing maize (Zea Mays L.), winter wheat(Triticum Aestivum L.), and black locust
(Robinia Pseudoacacia L.) under six different constant soil water levels in the pots and
under three water treatments in the plots. The plant growth and transpiration and
photosynthetic parameters were measured in different soil water treatments. The effects of
soil texture, plant and weather conditions on soil water availability were systemically
analyzed based on these measurements. With the Hydrus-1D model, the factors affecting
the response of root water uptake to soil water availability were discussed on a theoretical
basis. The main conclusions of this study were as follows:
(1) The responses of plant growth and transpiration of maize and winter wheat to soil water
stress were compared between the pot and plot experiments. Characteristic responses of the
various plant indices to changes in the soil water content obtained in the pot experiment
were applicable to the field, although large differences were found between the plants
grown in the pots and plots when considering their absolute plant growth and total
transpiration.  (2) The dynamic aspects of soil water availability were compared among different
physiological indices. With the linear-plateau function, the dynamic aspects of soil water
availability for various physiological indices showed the same trend with a threshold
response. The threshold values for the indices over the transient time scale were lower
than that over the daily and seasonal scales. The threshold values for indices related to
growth were lower than that related to transpiration. Higher threshold value was obtained
for daily transpiration before the filling stage, however, no significant difference were
obtained between the threshold values for indices related to growth before and after the
filling stage.
(3) The dynamic aspects of soil water availability for various physiological indices of
maize, winter wheat and black locust were also compared among different soils. The
average threshold values of relative soil water content for maize were larger for the loamy
clay than clay loam and sandy loam; near the broken capillary moisture, soil water
availability for maize was the largest for the clay loam, the medium for the sandy loam
and the least for the clay loam. The average threshold values of relative soil water content
for winter wheat were the largest for the sandy loam, the medium for the loamy clay and
the least for the clay loam; near broken capillary moisture, soil water availability for
winter wheat was the largest for the clay loam, the medium for the loamy clay and the
least for the sandy loam; The average threshold values of relative soil water content for
black locust were the largest for loamy clay, the medium for the sandy loam and the least
for the clay loam; near broken capillary moisture, soil water availability was the largest
for the loamy clay, the medium for the clay loam and the least for the sandy loam. The
capacity of draught resistance was the largest for black locust, the medium for winter
wheat and the least for maize.
(4) By comparing the dynamic aspects of soil water availability under different
weather conditions, we found that soil water availability in the loamy clay was
insusceptible to humidity variation under high temperature, but increased with the
humidity increasing under low temperature; soil water availability in the sandy loam
increased with humidity increasing under high temperature and decreased with humidity
increasing under high temperature; The effects of evaporative demand on the dynamic
aspects of soil water availability were different among different textured soils and plant  types. For maize, the threshold values of soil water content increased with the
evaporative demand increasing, but no significant difference could be found among
different ET0 levels. For winter wheat, the threshold values of soil water content
increased with the evaporative demand increasing, and significant higher threshold
values were obtained when ET0 > 3.0 mm d-1. For black locust, the threshold values of
soil water content in the sandy loam increased significantly when ET0 > 3.0 mm d-1 as
the evaporative demand increasing, however, in the loamy clay and clay loam, the
threshold values of soil water content decreased significantly.
(5) The Hydrus-1D model was selected to investigate the mechanism of the influence
of soil texture, plant growth and weather conditions on the dynamic aspects of soil water
availability. The plant selected for simulating was maize growing with different leaf area
index, root depth and root density distribution. Results showed the threshold values of soil
water content were quite different under different soil, plant and weather conditions,
among which root depth and root density distribution also had significant influence on the
shape of the dynamic curve of the soil water availability to plant. However, the response of
soil water availability to leaf area index and weather condition was different among
different soils. In general, the critical soil water content declined with soil texture in the
order: loamy clay > clay loam > sandy loam, increased as evaporative demand increasing
and decreased as root depth and root density distributed in the deep depth increasing.
The results showed that, with the normalized plant physiological indices, the soil
water availability to plant in the pot experiment could be applied in the field; the soil water
availability would be different when the plant indices used were different in time scales,
growth stages or related physiological processes; soil water availability was the plant
responses to soil water variation under the comprehensive effects of soil texture, weather
condition and plant growing state.
Keywords: soil water content, soil water availability, soil texture, evaporative demand

Language中文
Document Type学位论文
Identifierhttp://ir.iswc.ac.cn/handle/361005/8901
Collection水保所知识产出(1956---)
Recommended Citation
GB/T 7714
吴元芝. 黄土区土壤水分对典型植物有效性的研究[D]. 北京. 中国科学院研究生院,2010.
Files in This Item:
File Name/Size DocType Version Access License
黄土区土壤水分对典型植物有效性的研究.p(1528KB)学位论文 开放获取CC BY-NC-SAApplication Full Text
Related Services
Recommend this item
Bookmark
Usage statistics
Export to Endnote
Google Scholar
Similar articles in Google Scholar
[吴元芝]'s Articles
Baidu academic
Similar articles in Baidu academic
[吴元芝]'s Articles
Bing Scholar
Similar articles in Bing Scholar
[吴元芝]'s Articles
Terms of Use
No data!
Social Bookmark/Share
All comments (0)
No comment.
 

Items in the repository are protected by copyright, with all rights reserved, unless otherwise indicated.