| Panax notoginseng is one of the most important economic crops in Yunnan Province.The yield and water and fertilizer use efficiency is lower and disease incidence is higher in traditional Panax notoginseng planting.Optimizing irrigation and fertilization is the key to maximizing the yield,water and fertilizer use efficiency and quality of Panax notoginseng.In this study,the 2-year-old Panax notoginseng was chose as experiment material.The field treatment was started in March 2018,and conducted during main growing seasons in an experimental Panax notoginseng orchard in Luxi County,Yunnan,China.Based on the results of previous experiments and local planting experience,three irrigation levels(W1:100 m~3/hm~2,W2:150 m~3/hm~2,W3:200 m~3/hm~2)and four fertilization levels(F1:60 kg/hm~2,F2:90 kg/hm~2,F3:120 kg/hm~2,F4:150 kg/hm~2)were designed.The soil moisture,nutrients,soil enzyme activity,microbial quantity,disease incidence,growth characteristics,physiological characteristics,yield,water and fertilizer use efficiency and quality of Panax notoginseng were studied.The main results as follows:(1)The soil moisture content in the 20-30 cm soil layer was higher,while the soil moisture content in the 0-10 cm layer was lower;The soil p H of the 10-20 cm layer decreased gradually,and the treatment of W3F4 has the largest decrease in soil p H,while the treatment of W1F3 has the smallest decrease.In addition,with the extension of time,the content of soil nitrate nitrogen,available phosphorus and available potassium in the planting area of Panax notoginseng had varying degrees of decrease.(2)The number of soil bacteria in each period accounts for the largest proportion,followed by fungi,and the smallest proportion of actinomycetes.Different treatments had significant effects on the number of soil microorganisms and soil enzyme activities in the planting area of Panax notoginseng.During the four growth periods,the average number of bacteria and fungi in the soil under the treatment of W3 were largest,and the average number of actinomycetes in the soil under the treatment of W1 was the largest;the average invertase activity and urease activity of the soil under the treatment of W2 at the seedling stage were higher,the average catalase activity under the treatment of F2 was higher;In the growing period,the average catalase activity of soil under the treatment of W3 was higher,the average cellulase activity under the treatment of F3 was higher;In the flowering stage,the average soil catalase and cellulase activities under the treatment of W2were higher,the average soil catalase and invertase activities under the treatment of F1were higher;In the fruiting period,the average catalase activity and average cellulase activity of soil under the treatment of W3 were higher,the average catalase activity under the treatment of F2 was higher.(3)There were significant differences in the incidence of Panax notoginseng under different treatments.The incidence of Panax notoginseng increased with the increased of the volume of irrigation and fertilizer,the incidence of Panax notoginseng was higher under the treatments of W3F4 and W3F3,while the treatment of W1F1 and W1F3 had a lower incidence of Panax notoginseng.(4)The net photosynthetic rate,plant height and stem diameter of Panax notoginseng under the treatment of W3F3 were higher;the root morphological indexes under W2F4 and W3F4 treatments were better than other treatments;Compared with the flowering period,the net photosynthetic rate of Panax notoginseng leaves in other growth periods decreased by 58.59～79.84%,the net photosynthetic rate of Panax notoginseng leaves under the treatment of W2F3 and W3F3 was higher in each growth periods;Under the same level of fertilization in the flowering period,the transpiration rate of Panax notoginseng leaves increased with the increased of irrigation volume;The canopy hydraulic conductivity under the treatment of W1 was lower than the treatment of W2and W3 in each growth period.(5)Increased the amount of irrigation and fertilization were beneficial to increase the biomass accumulation of Panax notoginseng,but too much the amount of irrigation and fertilization was detrimental to the assimilate distribution of aboveground and underground parts;The dry weight of aboveground and underground parts of Panax notoginseng under the treatment of W3F4 was the largest,but the root cap ratio was lower than other treatments.(6)After analysis and calculation,the treatment of W2F3 was the best treatment for the yield,water and fertilizer use efficiency and quality of Panax notoginseng in this study. |
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