| 摘要 | 地膜具有增温保墒、保水抑盐，改善土壤水肥气热条件，促进作物高产稳产等
作用，在北方地区大面积推广应用，且使用量和覆盖面积呈增长趋势。但地膜厚度
一般为 0.008 mm，拉伸负荷较低，易破碎，残膜机械回收率低。随着使用年限的增
加，田间残膜量逐年增加，对土壤—作物生态系统的负面效应也日益凸显。本研究
通过室内土箱、土柱模拟和温室番茄种植相结合的试验方法，设置了 6 个残膜量水
平，分别为 0、80、160、320、640 和 1280 kg/hm 2 ，研究了不同残膜量对土壤水分
垂直入渗、蒸发和水平扩散及番茄生长发育的影响，为残膜污染地区农艺管理方式
提供参考。本文的主要结论如下：
1）残膜延长了土壤水分入渗时间，入渗至 45 cm 土层耗时随残膜量增加而增
大；入渗一定时间，含残膜处理的入渗曲线与无残膜曲线 分离，分离时间随残膜
量增加而提前，分离时间与残膜量之间呈对数函数减小；Kostiakov 模型更适合模拟
含残膜土壤的入渗过程；湿润锋运移距离与入渗时间呈幂函数增长关系，但湿润锋
运移距离随残膜量增加而递减；随残膜量增加，作物适宜生长区和水分分布重心逐
渐上移。残膜对土壤水分入渗有较大的不利影响，其影响程度随残膜量增加而增大。
2）随着残膜量增加，湿润锋垂直运移速率和累积入渗量逐渐减小；残膜量＞
80 kg/hm 2 时，湿润锋运移速率大幅下降；累积蒸发量随残膜量增加而递减，而蒸发
系数呈递增趋势；随残膜量增加，0～10 cm 和＞20～45 cm 土层质量含水率呈降低
趋势，而土壤水分的变异系数呈增加趋势，残膜加剧了土壤水分垂直分布的变异性，
残膜量＞320 kg/hm 2 的处理会出现表土层“板结”现象。基于 Gibbs 抽样算法分析
表明，Kostiakov 入渗模型和 Rose 蒸发模型各参数的 95%后验置信区间上下限的差
值和标准差均随残膜量增加而增大，累积入渗量和累积蒸发量的 95%后验置信区间
面积呈增大趋势，土壤累积入渗量和累积蒸发量的不确定性随残膜增多而增强。
3）残膜是一种难降解持续性污染物，会降低水平湿润锋运移速率、累积入渗
量和土壤水分扩散率，残膜对土壤水分水平运动的阻滞作用随残膜增多而增强。水
平湿润锋运移速率、土壤含水率和累积入渗量均随残膜量增加而减小，残膜量≥160kg/hm 2 时，水平湿润锋运移速率和累积入渗量大幅降低；残膜对土壤水分水平运动
的阻滞系数与残膜量呈正相关关系，残膜阻滞系数的最大增长率出现在 80～160
kg/hm 2 残膜量区间，增长率达 251.15%；随残膜量的增加，阻滞作用较强区域距离
入渗点的距离增大，Boltzmann 系数和水分扩散率则逐渐减小，土壤基质势对水分
水平运动的驱动作用和土壤持水能力逐渐减弱；但混有残膜的土壤水分水平运动过
程,仍符合土壤水分扩散率单一参数模型和 Kostiakov 入渗模型。
4）残膜阻碍了番茄苗期和开花坐果期根系的生长, 根体积、根长密度和根干质
量密度均随残膜量增加而降低; 随着残膜量增加, 苗期和开花坐果期的株高和茎粗
均呈减小趋势, 且株高和茎粗的增长速率逐渐降低。番茄养分积累的始盛期和高峰
期随残膜量增加而提前, 番茄追肥的最佳时期也应提前。在番茄苗期和开花坐果期,
根系、茎秆、花和幼果的干物质量均随残膜量增加而减少, 而叶片的干物质量呈递
增趋势。残膜对番茄苗期根系、地上部生长和干物质积累的阻碍作用高于开花坐果
期。由此可见, 残膜对番茄苗期的危害强于开花坐果期, 且干物质积累的始盛期和
高峰期均随残膜量增加而提前, 加强番茄苗期水肥管理和提前水肥施加时间是减轻
残膜危害的有利措施。
关键词：残膜；残膜量；阻滞；不确定性；土壤水分运移；番茄生长 |
| 其他摘要 | Plastic film could increase soil temperature and soil water content, raise soil water
capacity and restrain salt, improve soil micro-climate, reduce soil erosion, adjust soil
water fertilizer gas heat, which is conductive for crop growth. Plastic film is widely
spreaded and used in north China, application amount and covered area have a rising
trend. But the thickness of plastic film widespread is 0.008 mm. The tensile load of
plastic film is low, easy to broken, residual film mechanical recovery rate is low, which
lead to the amount of residual plastic film increases with increasing years of laminating.
In additions, the negative effects of residual plastic film on soil - crop ecosystem is
highlighted. Faced with current situation of increasingly severe residual membrane
contaminated, soil boxing experiment, soil column experiment and tomato planting
experiment were conducted. Based on these experiments, we explore the effects of
residual plastic film on soil water infiltration, horizontal movement, evaporation and
tomato growth. This study could provide a viable theoretival basis for formulating
irrigation scheme and crop scheme in area polluted by residual plastic film.The main
results of this study are as follows:
1) Residual plastic film prolonged infiltration time, and the consuming time that
water infiltrate to 45 cm increased with increase of residual plastic film. The infiltration
rate curve of treatments containing residual plastic film would separate with control
treatment T0 when water infiltrated to a certain depth. Separated time was shortened and
logarithmically decreased. Compared with Philip model and Green-Ampt model,
Kostiakov infiltration model was more suitable to simulate the process of water
infiltration in soil containing residual plastic film. Wetting front moving distance
increased exponentially with the prolonging of infiltration time, while there was negative
correlation between wetting front moving distance and accumulative quantities of residual plastic film. Residual plastic film had an adverse effect on the process of soil
water infiltration, which the disadvantageous effect would aggravate with the increment
of residual plastic film.
2) Residual plastic film would not only reduce the transport velocity of vertical
wetting front, but also decrease soil cumulative infiltration. When the amount of residual
plastic film was more than 80 kg/hm 2 , transport velocity of wetting front decreased
dramatically. As the amount of residual plastic film increased, consumed time that
wetting front arrived at 40 cm significantly prolonged (F=19.11, P<0.05). On the other
hand, cumulative evaporation significantly decreased when the amount of residual plastic
film was more than 160 kg/hm 2 (F=9.58, P<0.05). However, evaporation coefficient
increased with the increment of residual plastic film, which indicated that the water
holding capacity of soil decreased. Residual plastic film also changed the distribution of
soil moisture. As the amount of residual plastic film increased, gravimetric soil moisture
decreased at the 0~10 cm and ＞20～45 cm depth. At 0~10 cm depth, variable
coefficient of soil moisture increased by 4.33%, 127.19%, 330.40%, 539.63% and
640.23% compared with that for T0 treatment, respectively. Moreover, the variable
coefficient had a trend of decrease at ＞20～45 cm depth. This implies that the
inhomogeneity of soil water distribution was enhanced due to residual plastic film
pollution. Moreover, soil surface hardened when the amount of residual plastic film was
more than 320 kg/hm 2 . As the amount of residual plastic film increased, the 95%
confidence interval and standard error of posterior parameters all increased for the
Kostiakov infiltration model and Rose evaporation model according to Gibbs sampling
algorithm. The areas of posterior distribution intervals of cumulative infiltration and
evaporation also increased. In general, residual plastic film could increase the
uncertainties in soil water infiltration and evaporation.
3) The migration rate of horizontal wetting front, the accumulative infiltration
amount and volumetric soil water content gradually declined with the increase of residual
plastic film amount. When residual plastic film amount was more than 160 kg/hm 2 , the
migration rate of horizontal wetting front and the accumulative infiltration amount would
dramatically reduce. There were extremely significant positive correlation relationship
between the amount of residual plastic film and retardation coefficient. When the amount of residual plastic film ranges from 80 kg/hm 2 to160 kg/hm 2 , increase rate of retardation
coefficient reached up to 251.15%. The distance from stronger retardation region to
infiltration point was enlarged with increase of residual plastic film. However,
Boltzmann coefficient and water diffusivity were gradually declined, driving force of soil
matric potential on soil water diffusion and soil water holding ability wore off. The
horizontal diffusion process of soil mixed with residual plastic film still conforms to
single parameter model of soil water diffusivity.
4) Residual plastic film hindered the growth of tomato root at both seedling and
blooming and fruit-setting stages. Root volume, root length density and root dry weight
density decreased with increasing residual plastic film amount. In addition, as the amount
of plastic film residue increased, plant height and stem diameter decreased significantly
(P < 0.05). Besides, the rates of increase in plant height and stem diameter decreased
with increasing residual plastic film amount. Logistic model accurately simulated the
growth process of tomato in fields with residual plastic film less than 1 280 kg/hm 2 (R 2 >
0.87). As the amount of residual plastic film increased, beginning period and full period
of tomato biomass accumulation was ahead of time. This implied that the suitable time of
fertilization of tomato should be brought forward. Overall, biomass accumulation
decreased for the whole tomato growth period. Contrary to biomass accumulation of leaf,
that of root, stem, flower and young fruit decreased with increasing residual plastic film
amount. The hindering effects of residual plastic film on tomato growth and dry matter
accumulation at seedling stage were higher than at blooming and fruit-setting stage. The
early period and middle period of tomato biomass accumulation all occurred in
advanced.
Keywords: residual plastic film; amount of residual plastic film; ability of retarding
water horizontall movement; soil water movement; tomato growth |
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