| Summary: | 碩士 === 國立屏東科技大學 === 熱帶農業暨國際合作系 === 105 === Global warming over the last century has been threatening agricultural world. Numerous research have been conducted and applied to solve it. Super absorbent polymers (SAPs) are compounds that have the potential to prolonge soil moisture content for certain period of time. This study aimed at observing the corn plant growth and physiological properties change under different rate of SAP concentration combined with different irrigation levels and organic fertilizers rates. The experiment I was separated into two part. First experiment focused on effect of SAP application (250 kg/ha and 0 kg/ha) combined with two irrigation intervals described as once per weeks and once per three weeks. The corn seedlings received regular irrigation (once a day) until five leaves stages then drought stress initiated. On tasseling stage, the irrigation level then splitted into two groups, one stopped irrigation while the others continued. Overall, SAP treatments showed better corn growth performance than zero SAP treatments. The SAP 250 kg/ha was the best result on all variables while cooperated with two week irrigation interval (SAP250/2WI). At full maturity stage, SAP250/2WI had the highest plant height (131 cm), highest moisture content (44%), broadest leaf width (6.9 cm), shortest root length (32.6 cm), highest chlorophyll a (0.054 mg /g), highest chlorophyll b (0.018 mg /g), highest chlorophyll total (0.072 mg /g), highest carotenoid (6.48 mg /g), highest carbohydrate content (0.3 mg/g), highest starch content (0.37 mg/g), highest transpiration rate (0.4 µmol-2s-1), highest photosynthetic rate (0.2 µmol-2s-1) lowest substomatal CO2 (112 vpm), and lowest proline content (2.5 µmol.g-1). Similarly, in prolonged drought experiment, SAP treatments (SAP250/2WIS and SAP250/3WIS) showed domination over zero SAP treatments (SAP0/2WIS AND SAP0/3WIS). Accordingly, the SAP treatments showed better plant growth performance compared to non-SAP treatments. In experiment two, the rate 375 kg/ha SAP achieved the optimum results followed by 250 kg/ha SAP treatments. The combination of 375 kg/ha SAP and 100 kg/ha organic fertilizer (SAP375/100) showed the finest result compared to all treatments in all parameters. At full maturity stage, SAP375/100 had the highest plant height (119 cm), highest moisture content (38%) broadest leaf width (5 cm), shortest root length (31.25 cm), highest chlorophyll a (0.059 mg /g), highest chlorophyll b (0.022 mg /g), highest chlorophyll total (0.080 mg /g), highest carotenoid (5.94 mg /g), highest transpiration rate (0.4 µmol-2s-1), highest photosynthetic rate (1.4 µmol-2s-1) lowest substomatal CO2 (28 vpm), and lowest proline content (1.4 µmol.g-1). In conclusion, SAP application 250 kg/ha combined with two weeks irrigation interval can enhance both morphological and physiological traits of corn plant which were positive to drought protection at 83 days after sowing. Alternatively, the combination of SAP 375 kg/ha and organic fertilizer 100 kg/ha can enhance both morphological and physiological traits of corn plant under drought stress.
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