Study On The Key Technologies Of Factory Production For Industrial Hemp

As an important economic crop,industrial hemp has been globally cultivated and has shown great value in textiles,food,building materials,health care and medicine.Hundreds of cannabinol compounds can be synthesized in industrial hemp,among which the cannabidiol（CBD）has become a hot spot for studying with the higher medical value.Driven by the economic and social benefits,many countries have increased their investments in hemp breeding and efficient cultivation to obtain the high-CBD content.Among the cultivating technologies,facilities cultivation is paid much more attention for its advantages,such as better controllability,higher space utilization efficiency,and higher crop yield.In the present study,experiments for the simulation of factory production were conducted to explore the suitable illumination conditions and nutrient solution compositions for facilitiles cultivation of hemp with the breed of“Xinma1”.Through the study,two spectra of light-emitting diode（LED）and nutrient solution formulations were selected,which were suitable for the growth of hemp seedlings;the nutrient of nitrogen（N）,phosphorus（P）,and potassium（K）requirements regularity for hemp were analyzed and the indexes of growth,biomass,and the main medicinal components on hemp were identified.Finally,a series of technical parameters were obtained through data analysis,which can provide a scientific reference for industrial hemp factory production and improving CBD yield.1.The effects of different spectrums CK（high-pressure sodium lamp）and LED on the growth,biomass,and main medicinal components of industrial hemp were studied.The results showed that compared with CK（high-pressure sodium lamp;R:B 9.3:1;PPFD 151）,LED2（red:blue ratio（R:B）1.61:1;PPFD 540）and LED5（R:B 16.8:1;PPFD 252）could better promote the growth of hemp in terms of plant height,stem diameter and leaf number,and notably improved the aboveground biomass with an increment of 55.1%and 15.2%;the biomass of hemp inflorescence for LED5 and LED2 were also markedly increased compared with that for CK with increments of 61.5%and 238%,respectively.LED2could significantly increase the CBD content of both leaves（1.81%）and inflorescence（5.83%）compared to CK（leaves 1.38%,inflorescence 4.27%）while LED5 only notably increased the CBD content of leaves;the theoretic CBD yield for a per plant of LED2 and LED5 was 26.8%and 9.0%higher than that of CK,respectively.The results showed that LED2 and LED5 were suitable for the efficient cultivation and increasing CBD yield of industrial hemp.2.To develop suitable nutrient solution formulas for the growth of industrial hemp seedlings,the nutrition of industrial hemp,four nutrient solution formulas（1 Z,1/2 Z,1/4 Z,and 1/8 Z）were redesigned base on the Hogland nutrient solution formula.The results showed that,compared to 1 H（standard Hoagland nutrient solution formula）,1 Z showed no significant effects on the growth and development of industrial hemp seedlings;1/4 Z can significantly increase the leaf area（up to 1350 mm²/per leaf）and produce the greatest biomass（about 1.99 g/per plant）,which were 5.8 and 2.2 times that of the 1 H;1/8Z promoted the growth of plant height,root length,and root numbers.In conclusion,1/4 Z and 1/8 Z are more suitable nutrient solution formulas for hydroponics of industrial hemp seedlings.3.Based on the developed nutrient solution formulas and LED5,an orthogonal experiment was conducted to select the suitable ratio of N,P,and K for"Xinma No.1".The results showed that,compared with the treatment of A6（N₆P₂K₃）（N:P:K 6:2:3）,A7（N₈P₁K5）and A8(N₈P_1.5K₃)can significantly improve the plant height,stem diameter,and the dry weight of stem with leaves was also notably increased by 105.14%and 78.4%,respectively;compared with A6（N₆P₂K₃）,A7（N₈P₁K5）and A8(N₈P_1.5K₃)increased the root biomass by 161.68%and 202.80%respectively,and dry inflorescence biomass by238.46%and 476.92%,respectively.Compared with the treatment of A3（N₄P₂K₅）,the CBD content of inflorescence in the treatment of A1（N₄P₁K₃）and A7（N₈P₁K₅）were significantly increased by 36.0%and 42.8%,and the total CBD content in the two treatments was increased by 41.81%and 36.28%,respectively.Thus,the ratio of N,P,K of 8:1:5 is more suitable for the growth of industrial hemp.