Studies On The Appropriate Physical And Chemical Properties Of Substrate And Dosage Of Nitrogen,Phosphorus And Potassium For Plug Seedling Production Of Eggplant

As a representative of vegetable intensive seedling,the plug seedling has become a new industry,and become more large-scale,professional and modern day by day.Substrate is the media of seedling growth,and has the direct effect of seedling quality.At present,the research of the eggplant plug seedling is mostly based on the select of peat substitute substrates or formula,but the research on appropriate physical and chemical properties of substrate and dosage of nutrient for plug seedling on eggplant has been lacking in perfection.In this paper,the eggplant was used for the material,and using peat,vermiculite and perlite as the seedling substrate,the appropriate physical and chemical properties of substrate was studied by the mixing test design.Based on this,the dosage of nutrient was studied by the quadratic saturation D-optimal design,and through the simulation of computer to determined the appropriate nutrient of eggplant seedling,the research is hoped for promote the standardization of seedling substrate,simplify the management of seedling water and fertilizer,improve the quality of seedling.The main results are shown as follows:1.The results showed that plant height,stem diameter,the dry matter weight and seedling index of eggplant seedlings were the largest while the complex substrate ratio was peat: vermiculite: perlite = 5: 2: 3?V: V: V?.Based on the contour map from the observations of seedling index,the optimum volume ratio in 95% confidence interval for seedling substrate of eggplant was peat at 36%⁶2%,vermiculite at 20%²7%,and perlite at 35%⁴3%.The regression model between physical and chemical properties and volume ratio was established,and the appropriate properties of substrate for eggplant seedlings production through the calculation of LINGO11.0 were bulk density 0.25⁰.41 g·cm^-3,total porosity 73⁸9%,p H 6.3⁷.8,EC 0.59⁰.93 ms·cm^-1 [substrate: distilled water=1: 5?W/V?],available nitrogen 612.9⁸30.1 mg·kg-1,available phosphorus 61.6¹03.4 mg·kg-1,available potassium 184.6²99.3 mg·kg-1,total organic matter 30.5⁵2.6%.And by verifying experiment,the results showed that the optimum physical and chemical properties were suitable for eggplant plug seedling.In this case,the formula of peat,vermiculite and perlite?volume ratio,4: 2: 4?was better for seedling quality.2.Based on the research above,we found the nutrient need of eggplant seedling,that's N 0.0194 g·plant^-1,P 0.0101 g·plant^-1,K 0.0490 g·plant^-1,and the absorption and distribution of N,P and K in different parts of eggplant seedlings were different.Among them,all of N,P and K in the leaves were the highest of all parts,then stem,and the root was the least.However,there were about 55.87%?N??51.23%?P?and 48.80%?K?of total seedling in the part of leaves.The distribution of K in root was less than the distribution of N and P.But in the root was the opposite,the distribution of K was high than the ratio of N and P.3.The ternary quadratic mathematical model was established,and using the application of N,P,K as the variable factor,and the seedling index as the dependent factor.Through the model,we found that three elements all have the influence to seedling index,and nitrogen dose most,then phosphor,and potassium was last.By the analysis of single factor effect,we found when the effect value achieve to maximum,the scheme of nitrogen,phosphorus,potassium is 480.94 g·m^-3?729.99 g·m^-3?886.66 g·m^-3,respectively.By the analysis of marginal effect,when the value reduce to 0,the scheme of nitrogen,phosphor,potassium is 419.19 g·m^-3?710.22 g·m^-3?861.51 g·m^-3.Thus through the simulation of optimization design,we found that in this experiment,the scheme of seedling index reaches 0.22 is N 0.1393⁰.3607,P-0.2014⁰.1537,K-0.2710⁰.1281 in coded value,and N 460.00⁵36.37 g·m^-3,P₂O₅ 567.79⁸16.70 g·m^-3,K2 O 633.36⁹69.16 g·m^-3 in actual value,including the nutrient of substrate.When the seedling index was the highest,the actual value was N 479.15 g·m^-3,P₂O₅ 731.18 g·m^-3,K2 O 689.91 g·m^-3,and still including the nutrient of substrate.4.The results of verifying experiment of dosage was indicated that these were no significant difference of plant height,stem diameter,fresh and dry weight,and seedling index between the free-nutrient solution treatment?V1?and watering by nutrient solution treatment?CK?.The content of Chlorophy II b in CK was higher than V1,but still no significant drfference of Pn,Chlorophy II a content,carotene content,root vigor and root absorption area between V1 and CK.Thus,the difference of V1 and CK is not obvious,and both two treatments could reach the need of eggplant plug seedling.The formula of free-nutrient solution chould be the standardization of seedling substrate,simplify the management of water and fertilizer in seedling.It is suggested that the formula of N 479.15 g·m^-3,P₂O₅ 731.18 g·m^-3,K2 O 689.91 g·m^-3 as the free-nutrient solution formula of eggplant intensive plug seedling to be promoted in seedling industry.