| In order to study the effects of drip irrigation and drip fertilization for 1 and 2-year-old Cinnamomum camphora juvenile plantation,the dynamic of soil water content,the growth and photosynthetic characteristics under drip irrigation among different watering quantity and different fertilizer application quantity in Jingshan,northwest of Yuhang,Zhejiang province during 2016 and2017.The main results are as follows:(1)The vertical distribution of root system is mainly in 0 to 30 cm soil layer underground for 1 and 2-year-old Cinnamomum camphora plantation and in 0 to 40 cm soil layer underground for 3 to 5-year-old Cinnamomum camphora plantation.The one time irrigation duration is 4 to 5 hours and one time effective watering quantity is 13.3 to 16.7 mm.The one time irrigation duration is at least 6 hours and one time effective watering quantity is 20.0 mm.The interval time should not exceed 130 hours or 125 hours between two times irrigation for 1 and 2-year-old or 3 to 5-year-old Cinnamomum camphora plantation respectively under the condition of no rainfall in dry season.(2)Based on the horizontal and vertical moving distance of soil water front after 6 hours irrigation,the reasonable spacing between two drips on drip line should be 40 to 50 cm.When water flow of 2 liters / hour each dripper is adopted,because the successive humid body can be formed along drip line in soil layer of 0 to 30 cm or 0 to 40 cm after irrigation of at least 4 hours or 5 hours when the space of two drippers is 40 cm and 50 cm respectively.(3)For 2-year-old Cinnamomum camphora plantation with drip irrigation,the annual increment of tree height and ground diameter was 15.53% and 28.92% more than the plantation with conventional cultivation respectively,while with maintaining the soil water content always higher than 80% and 75% of field water capacity respectively during the growing seasons.Under drip irrigation,the biomass of 2-year-old Cinnamomum camphora tree was 58.73% more than that of the tree under conventional cultivation,in which the biomass of leaf and branch that are the economic products was 59.19% and 59.61% more than that of the tree under conventional cultivation respectively.Throughout the growing seasons,there were two peaks of fast growing period in tree height and ground diameter growth of 2-year-old Cinnamomum camphora tree both under drip irrigation and conventional cultivation,but the second peak of fast growing period appeared one month earlier under drip irrigation than that under conventional cultivation.(4)The net photosynthetic rate(Pn),stomatal conductance(Gs)and transpiration rate(Tr)of 2-year-old Cinnamomum camphora tree were significantly increased under drip irrigation comparing those under conventional cultivation,with their similar model of variation,i.e.their value increased with increasing of irrigation quantity within certain quantity range and decreased while giving the irrigation quantity beyond the range.Comparing the conventional cultivation,the drip irrigation resulted in the highher LSP and AQY,and lower LCP and Rd in the leaves of Cinnamomum camphora tree.(5)According to the performance of the tree height and ground diameter growth,biomass as well as the photosynthetic and other physiological features of 2-year-old Cinnamomum camphora plantation under drip irrigation in different irrigation quantities,the maximum growth increment and economic product yeild can be achieved under drip irrigation with maintaining the soil water content always higher than 80% of field water capacity.Based on the drip irrigation model mentioned above,the annual drip irrigation program was made for 2-year-old Cinnamomum camphora plantation,i.e.16 times of irrigation by totally irrigation quantity of 248.2 mm should be given with one time irrigation duration was 4 to 5 hours,with one time irrigation quantity of 13.3 to 16.7 mm during begining May and begining October,to achieve the maximum growth increment and economic product yeild of 2-year-old Cinnamomum camphora plantation.(6)For 1-year-old Cinnamomum camphora plantation with drip fertilization,the annual increment of tree height and ground diameter was 15.53% and 28.92% more than the plantitation with conventional fertilization respectively,while the optimal drip fertilizer application quantity was N 26.0 g/tree,P 2.6 g/tree,K 16.9 g/tree.Under drip fertilization,the biomass of 1-year-old Cinnamomum camphora tree was 79.44% more than that of the tree under conventional fertilization,in which the biomass of leaf and branch that are the economic products was 80.91% and 75.40% more than that of the tree under conventional fertilization respectively.Throughout the growing seasons,there was one or two peaks of fast growing period in tree height or ground diameter growth of 1-year-old Cinnamomum camphora tree both under drip fertilization and conventional fertilization,and those one or two peaks was both in the same month respectively.(7)The net photosynthetic rate(Pn),stomatal conductance(Gs)and transpiration rate(Tr)of 1-year-old Cinnamomum camphora tree were significantly increased under drip fertilization comparing those under conventional fertilization,with their similar model of variation,i.e.their value increased with increasing of fertilizer application quantity within certain quantity range and decreased while giving the fertilizer application quantity beyond the range.Comparing the conventional fertilization,the drip fertilization resulted in the highher LSP and AQY,and lower LCP and Rd in the leaves of Cinnamomum camphora tree.(8)According to the performance of the tree height and ground diameter growth,biomass as well as the photosynthetic and other physiological features of 1-year-old Cinnamomum camphora plantation under drip fertilization in different fertilizer application quantities,the maximum growth increment and economic product yeild can be achieved under drip fertilization with fertilizing N 26.0 g/tree,P 2.6 g/tree,K 16.9 g/tree.Based on the drip fertilization model mentioned above,the annual drip scheme was made for 1-year-old Cinnamomum camphora plantation,i.e.16 times of fertilization by totally fertilizer application quantity of N 26.0 g/tree,P 2.6 g/tree,K 16.9 g/tree should be given with one time fertilizer application quantity was N 1.18 g/tree,P 0.12 g/tree,K 0.77 g/tree,with 2 times of one time fertilizer application quantity in August and September during begining May and begining October,to achieve the maximum growth increment and economic product yeild of 1-year-old Cinnamomum camphora plantation. |
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