| Pinus massoniana is the extremely important species to product timber and resin in southern China. It demand larg quantity and high quality seedling. For ensure accurate water and nutrient supply in seedling stage, reduce the waste of water and nutrient and the eutrophication pollution of natural water, moisture control experiment by potting, nutrient control experiment by hydroponics were carry out, the study goal is to provide theoretical and technical support for water and nutriment control in precision seedling of Pinus massoniana.The conclusions are as follows:(1) Under differential water supply, the total water consumption, monthly water consumption and daily water consumption of Pinus massoniana seedling were different. There is a positive correlation between water supply and consumption. At seedling stage, the total water consumption of individual seedling under differential water supply showed that No.1(176.42ml)>No.3(263.04ml)>No.2(256.5ml)>No.4(202.63ml)>No.5(167.93ml). The monthly water consumption of individual seedling in different seedling age showed that 46~78d>79~107d>108~136d>137~170d. Except 46~78d, the others showed difference significantly in monthly water consumption. Their average consumption is 80.39~88.93 ml, after 79 d, the monthly water consumption of No.1~No.3 was higher than No.4 and No.5.(2) The results showed there are no significant difference of the seeding height and ground diameter when the matrix’s field capacity among of 80%~60%, but their growth in height and ground diameter was higher than the matrix’s field capacity among of 50%~40%. If the matrix’s field capacity below 50%, the seeding growth was limited. The seeding’s root growth showed significant difference under differential water supply.When the matrix’s field capacity below 50% or above 70%, the seeding root growth was limited;When the matrix’s field capacity equal to 60%, the root grew best, with 280.43±35.051 cm total root length, 76.24±10.785cm2 root surface area,0.87±0.031 mm average root diameter and 253.7±36.87 number of root tip, the biomass also was significantly higher than other water supply treatment, the root biomass rate is also higher.(3) In the whole seedling stage, the N(Nitrogen) content in needle of Pinus massoniana was stable under different water supply states. The effect of different water treatment to N absorption of seedling was not significant. There were low level of P(Phosphorus) and K(Potassium) until seeding age under 107 d, but there were high level after 108 d. There were no apparent law on K absorption of sedling under different water supply.(4) Under differential moisture gradient, the SOD activity in the seeding with age decreases slowly. It negatively correlated with MDA content. The difference of chloroplast content was extremely significant(p<0.01) with moisture gradient, the chloroplast content was the hightest when the field capacity of 60%. If the matrix’s field capacity above 50%, the the moisture and related moisture of the needle decreased, the pralines content of needle increased, and soluble sugar also decreased. It indicated the field capacity of 60% was suitable for seedling growth, the field capacity of 70% rank second, When moisture gradient below 50% or above 80% field capacity would couse drought stress or waterlogging stress to the seedling in some degree, it is not beneficial to the growth of Pinus massoniana seedling.(5) The matrix’s field capacity of 60%~70% is the most suitable to growth of Pinus massoniana seedling. The total water consumption of individual is 256.5~263.04 ml for the age of 40d~170d of the seedling, the monthly water consumption of individual was different with seedling age, the water consumption of 46~78d, 79~107d, 108~156d and 137~170d were 80~88.93 ml,67.8~76.42 ml, 52.79~58.53 ml and 34.47~36.66 ml respectively.(6) The results of hydroponic experiment under different concentrate nutrient solution indicated that daily consumption of various elements in the same seedling ages were not same, daily consumption of the same element at different times also were not same, and consumption of different elements under different treatment showed significant difference. Consumption of each element gradually reduced with nutrients concentration reduced.Day consumption peaks of N per plant occurred at 14~63d, 97~109d and 128~144d, respectively; P element consumption peaks occurred at 64~79d and 97~109d; K element consumption peaks occurred at 30~45d, after the 46 d entered a period of low consumption, starting from 64 d, has a constant high consumption, consumption reduced gradually after 145 d. Ca elements consumption peaks occurred at 45~79d, 109~127d age, showed low consumption at 8 128 d seedling age. Consumption of Mg elements is highest in 14~45d, Ca consumption has no significant differences before 145 d seedling age.( 7) The consumption of five elements(N,P,K,Ca,Mg) for Pinus massoniana seedlings were not different under different nutrient supply, but the nutrient consumption between different treatments showed no significant differences. Except N elements, consumption of other elements showed decreased with decreasing concentration of nutrient supply.Highest monthly consumption of N elements was in the 46~78d, at this stage, the consumption of number 1 to mumber four accounts for 37.45%, 47.15%, 54.51% and 68.87% of total consumption of full growing season. lowest consumption phase were 140~170d; On the whole, P element consumption is high at 46~139d, but the consumption is low at other stages; For K consumption, treatment 1 and treatment 2 is the highest at 14~45d,and treatment 3 and treatment 4 is highest at 46~78d, and reduced with the seedling age increased; For Ca element consumption, treatment 1 to treatment 3 is the highest at 46~78d, then decreased with the increased of seedling age, treatment 4 is highest in 79~139d; Mg of elements consumption is the highest at 14~45d, the consumption of number 1 to mumber four accounts for 29.84%, 31.02%, 24.9 and 31.68% of total consumption of full growing season, and the consumption decreased with seedling age.increased.(8)Under different nutrient supply, the total consumption of N, P, K, Ca, Mg of Pinus massoniana seedlings showed difference significantly(p<0.05) at the whole growth stage, and decreased with nutrient concentrations. The rank of the consumption of different element in treatement 1 and reatement 2 is K>N>Ca>P>Mg, is N>Mg>K>P>Ca in treatment and is N>Mg>K>Ca>P in treatment 4.(9) The results of seedling growth determination under different nutrient gradients showed that the net growth of the largest of seedling height and stem diameter were 0.4 times nutrient solution of Hoagland’s, under the treatment, the Pinus massoniana seedlings biomass,SOD activity and chlorophyll contents were highest, with lower MDA content. this treatment helps to improve the quality of growth and physiology of Pinus massoniana seedling.(10) Take 0.4 Hoagland’s nutrient as optimal nutrient supply of Pinus massoniana seedling, we calculated demand of Pinus massoniana seedling to different element at different seedling ages. The demand amount of N elements for Pinus massoniana seedling is the highest, but demand amount of P elements is the lowest. Demand of each element, respectively N:19.983 mg, P:4.383 mg, K:7.016 mg, Ca:4.905 mg, Mg:9.229 mg.(11) According to optimal nutrient supply of 0.4 Hoagland’s nutrient, we made the nutrient supply project of Pinus massoniana at different seedling ages. At 14~45d: N, P, K, Ca and Mg is 2.711, 1.749, 0.983, 0.905 and 2.923 mg ·per seedling per month, at 46~78d: N, P, K, Ca and Mg is 14.697, 1.076, 2.029, 0.908 and 1.391 mg ·per seedling per month, at 79~108d: N, P, K, Ca and Mg is 2.242, 1.012, 1.625, 1.231 and 2.2 mg per seedling per month, at 109~139d: N, P, K, Ca and Mg is 1.417, 0.824, 1.993, 1.592 and 1.764 mg per seedling per month, at 140~170d: N, P, K, Ca and Mg is 0.272, 0.596, 0.386, 0.721, 0.95 mg per seedling per month. This project provide a reference for precision nutrient supply in seedling cultivation of Pinus massoniana. |
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