| Maize yield-increasing mechanism of supple mental irrigation with harvested rainwater in semi-arid areas of the Loess Plateau |
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| DOI：10.7606/j.issn.1000-7601.2008.04.02 |
| Key Words: upplemental irrigation with harvested rainwater maize photosynthesis yield |
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| Abstract: |
| Aimed at measures of water-saving agriculture in semi-arid mountain areas of the Loess Plateau this paper analyzed the influence of the maize photosynthesis yield and dry matter accumulation under different irrigation treat ments．The results show that the diurnal variation curve of photosynthesis factors appears updown open parabola type under different treat ments. Under different strength of illumination the diurnal variation rule of photosynthesis factors is very obvious ．Intercellular CO2 concentration of treat ment of 22．5 mm irrigation in jointing stage is bigger than other treat ments before 13∶00and 19∶00 but during remainder ti me intercellular CO2 concentration is smaller than other treat ments ．This rule is opposite for other photosynthesis factors which indicates that the strength of illumination is playing a vital role to the photosynthesis factor diurnal variation．Under great strength of illumination irrigation treat ments enhance leaf’s photosynthesis rate transpiration rate and stomatal conductance causing the intercellular CO2 concentration reduction ．As for maxi mum value of photosynthesis factors at about 13∶00 photosynthesis rate of treat ments of 22．5 mm and 15 mm irrigation in jointing stage is increased by 23．9％ and 15．0％ respectively and transpiration rate by 47．7％ and 17．7％ respectively and yield rate by 43．02％ and 29．48％ respectively compared with CK．Supplemental irrigation of harvested rainwater can also raise the dry matter accumulation quantity and yield to great extent． |