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Study on Optimal Irrigation Index of Soil Water for Cucumber at Different Growth Stages

Author: LiaoKai
Tutor: FanXingKe
School: Graduate School,Chinese Academy of Sciences
Course: Soil and Water Conservation and Desertification Combating
Keywords: Cucumber Growing season Limits of soil moisture Soil moisture limit Yield Quality Shoot ratio Water production function Water use efficiency
CLC: S642.2
Type: Master's thesis
Year: 2011
Downloads: 66
Quote: 0
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Abstract

Soil moisture status is one of the main factors affecting crop production for field crops, irrigation is one of the important measures to recharge soil moisture. As for the facilities, agriculture, irrigation is the only way of crop moisture. This paper for the test to the cucumber crop, a pot experiment, simulation mulch drip irrigation conditions by set different soil moisture in the various stages of its growth, the lower limit processing to study the various growth stages of cucumber water consumption characteristics and laws, as well as different soil moisture upper and lower handle on cucumber growth indicators, physiological indexes, yield, quality and water use efficiency through the analysis of the cucumber water consumption and the moisture production function, in order to determine the various growth stages suitable soil moisture, the lower limit for the Sun cucumber smart irrigation control system to provide reliable irrigation technical parameters under greenhouse conditions. According to the results of the following main conclusions: 1) the impact of the results of different growing season moisture treatments on cucumber growth indicators show that before: early flowering open irrigation soil moisture (irrigation lower limit) can lower the soil moisture to field capacity 55% of the water as the lower limit. For the initial stage of growth, moderate water stress conducive to the promotion of cucumber root development, and expand the range of utilization of cucumber roots on soil moisture and improve soil moisture use efficiency, promote the role of a certain degree of of late plant height growth, rehydration strains high compensation benefit is obvious. Cucumber growth period, the appropriate water deficit are conducive to the growth of stem diameter, early Guaqi higher soil moisture is conducive to the growth of leaf area, Sheng Guaqi is too low soil moisture Branch fiction cucumber leaves area growth. 2) the impact of the different growing season moisture treatments on physiological indexes of cucumber: The results show that throughout the growing stage, the strong photosynthetic rate, transpiration rate and stomatal conductance, stomatal conductance and transpiration rate and photosynthetic rate presented basic the same variation. Cucumber leaves in early flowering and Guaqi diurnal variation of photosynthetic parameters of a single peak curve, and reaches its maximum at 12:00. Early Guaqi diurnal variation of photosynthetic parameters are bimodal curve, at 12:00, \greater than the the 10:00 peak, but the peak of stomatal conductance and transpiration rate 14:00 10:00 peak. Early flowering and early fruit stages lower limits of soil moisture treatment are more conducive to of cucumber initial Guaqi photosynthetic parameters to improve Sheng Guaqi too high or too low limits of soil moisture treatment will reduce the photosynthetic parameter values, Sheng Guaqi soil moisture maintained at from 75 to 90% of field capacity can be increased photosynthetic parameters values. 3) the various growth stages of different limits of soil moisture treatment cucumber quality trends relatively consistent increase in the indicators with each period set limits of soil moisture reduction, that is moderate to control the water supply of water deficit can improve fruit quality. The processing of ground stem and leaf dry weight, the underground root dry weight and root to shoot ratio set lower limits of soil moisture and increase. Relations point of view, from the plant height and the underground root dry weight and root to shoot ratio early flowering and early Guaqi of basically showing plant height greater the underground root dry weight and root to shoot ratio law gradually increases, indicating that the aerial parts The underground portion of the growth is a good agreement. 4) to maintain 55 to 90% of field capacity in the early flowering, early fruit stages 75 to 90% of field capacity, the Sheng Guaqi 75 to 90% of field capacity (ie handling A3), not only to meet the consumption of cucumber whole growing season water demand, you can also get the highest yield (0.834kg / strain) and the the maximum moisture use efficiency (39.36g/kg) to achieve high productivity and efficient at the same time. Coincide, and cucumber growth and development of the law of demand for water throughout the growing period, the cucumber water consumption was anxious after the first slow growth trend. Water intensity of each treatment Sheng Guaqi gt; gt early Guaqi; early flowering stage, and with the continuous extension of the growing season, the difference between the average daily water consumption for each treatment and more obvious. 5) Jensen model simulation results of the test results showed that: cucumber water production function in the production of each growing season moisture sensitive index for Sheng Guaqi gt; gt early Guaqi; early flowering were 0.635,0.290,0.275. Sheng Guaqi moisture sensitive index, indicating that at this stage if the soil moisture content is low or insufficient soil moisture, will cause serious cuts losses will ultimately yield a greater impact. Early flowering sensitive index minimum, the description of the early flowering moderate water deficit has little effect on the production of late, to allow a short period of time appropriate water deficit in the early flowering stage. The early Guaqi cucumbers from vegetative growth to reproductive growth over the period, the the cucumber water demand gradually increase, proper water stress on cucumber final yield impact is not great. 6) 90% of field capacity as irrigation maximum processing conditions, the cucumber plants, regardless of the growth index, photosynthetic parameters of fruit quality or ground stems and leaves of the Ministry of dry weight, root dry weight and root to shoot ratio, are better than field capacity As the processing irrigation ceiling. Irrigation maximum process yield per plant is only 90% of field capacity as processed than field capacity irrigation maximum yield per plant decreased by 0.9%, but the efficiency of water use has increased by 16.84%. 90% field capacity the cucumber more appropriate indicators of the maximum water-saving irrigation. 7) (spring and summer) solar greenhouse cucumber at different growth stages began to the minimum irrigation control soil moisture, respectively, as follows: 55 percent of field capacity of the early flowering stage, early Guaqi 75% field capacity, Sheng Guaqi to 75% of field capacity . 90% of field capacity is appropriate to control the upper limit of soil moisture content in irrigation water throughout the growing period.

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