Advances in Soilless Culture Research

Soilless culture refers to the technique by which crops are grown using nutrient solution or solid substrate along with nutrient solution without natural soil. This technique has developed for more than 150 years, and plays an essential role in promoting the development of horticultural, agricultural and forestal production, as well as agricultural modernization. Substrate and nutrient solution formulae and their application are the core of soilless culture technique. Based on the classification system of soilless culture, the types, advantages and scope of application of substrate formulae for growing vegetables and flowers in soilless culture, as well as the types, advantages and scope of application of nutrient solution formulae, and the regulation of nutrient solution ingredients are first systematically summarized in this paper; then, the advantages and disadvantages of the inorganic energy-intensive soilless culture and eco-organic soilless culture, and their scopes of application are analyzed; finally, research directions for further perfecting soilless culture technique are presented, and the outlook for the application of soilless culture is also provided.

Study on Soilless Culture of Facility Strawberry

[Objective] The aim was to establish a set of soilless cultivation and management method of facility strawberry cultivation in the south of China.[Method] In the research,strawberry species,substrate formulae,cultivation modes and nutri ent solutions were selected and optimized.[Result] Three-dimensional strawberry cultivation was much suitable for Frandy,Hongbao and Gumei No.1; substrate with coconut shred-mushroom residue-peat soil ratio at 2∶2∶1 was the optimal; the treatment C3,containing Ca（NO3）2·4H2O,KNO3,（NH4）2HPO4,MgSO4·7H2O,and NH4NO3 at 280,303,62,246 and 80 mg/L,promoted strawberry growth,and the cultivated strawberry was large and thick in leaves,thick in stem,dark green in leaf color,with best fruit yield and quality.Among three cultivation modes,the density,space use ratio and yield in the treatment with PVC pipes in A-shape were all higher and the strawberry was easier and more convenient for picking.[Conclusion] The research provides references for soilless cultivation of strawberry in the south of China.

The optimal drainage line of potted flowers of soilless culture

Water is the source of life. China ranks No.13 among the water shortage countries. The most of the water is utilized in agriculture, while the utilization rate of irrigation water is only 40%, so it is very important to study on the theory and technology on high efficient water utilization. The purpose for this study is to find out the optimal drainage line on potted flowers through the analysis of experimental results of Aglaonema modestum and Rhododendron simsii Planch in different drainage lines.

Systems of Soilless Culture in China

Soilless culture in China has developed rapidly in recent years. The area of soilless culture in China was about 0.1 ha in 1985, 117 ha in 1995, but in 2002 the area reached to 865 ha. This paper introduced the brief history of soilless culture in China, and the main soilless culture systems. The present situation and problems are also discussed in this paper.

Effects of Substrates before and after Fermenting Treatment on the Growth,Development and Cut Flower Quality of Lily

[Objective] The aim of this study was to explore the effects of substrates before and after fermenting treatment on the growth,development and cut flower quality of lily.[Method] Oriental lily cultivar ＇Siberia＇ was taken as material to study the effect of using fermentative and unfermented agricultural waste as substrates on the growth,development and cut flower quality of lily.And the physical and chemical properties of substrates before and after fermenting treatment were studied.[Result] The full decomposition of agricultural waste would greatly improve the physical and chemical properties of substrates,such as the fermentative substrates changed to stabilization,the ratio of carbon nitrogen had dropped drastically,the total porosity was increase,the ratio of gas and water was better,and the nutrition elements was increased.Moreover,it could significantly increased the plant height,stem diameter,leaf number,leaf area,leaf fresh weight and so on,as well as expanded the lily roots and significantly improved the rate of cut flower and cut flower quality.[Conclusion] This study had provided theoretically basis for the cultivation of cut lily.

Overview of the aeroponic agriculture-An emerging technology for global food security

Traditionally,crops are cultivated in soil-based open field systems.Seasonality,environmental degradation,urbanization,and food security issues have replaced open-field systems with modern plant production systems.Soilless culture is one of the modern plant production systems,which involves much higher use of available resources.The presented study provides information about currently accessible soilless systems and discussed the aeroponic system.Compared to other soilless systems,aeroponic reduce water usage through continuous water circulation.However,the aeroponic is not entirely implemented among local farmers,and very few farmers have adopted the system due to the lack of research and technical information available in the literature.Therefore,this study was planned to provide information about the development and maintenance tasks required for practicing the aeroponic system.This study could provide knowledge to the researchers,farmers,and those people interested in practicing the aeroponic system.

Estimating EC and ionic EC contribution percentage of nutrient solution based on ionic activity

The dynamic monitoring technology of inorganic ions using ion selective electrodes has some problems such as low precision,vulnerability to other ions,short service life,and high price.Due to the difficulty of dynamic control based on ionic concentration of nutrient solution,EC and pH values of nutrient solution are often used as feedback control indexes in hydroponic system.In this study,estimation algorisms of EC and ionic EC contribution percentage based on ionic activity were proposed to understand the quantitative relationship between ionic concentration and EC.With a view to predicting the EC accurately by mean ionic activities of specific salts in nutrient solution based on a specific formula,ionic concentration could also be calculated by the actual measurement of EC combined with ionic EC contribution percentage.With Japanese horticultural experimental nutrient formula and Yamasaki tomato nutrient formula,significant linear correlations between estimated EC and measured EC were found with determination coefficients over 0.99.Ionic EC contribution percentage was not affected by different relative concentrations of nutrient solutions.However,ionic EC contribution percentage changed significantly when adding specific salts with different concentrations,and different changes were found in each anions and cations of specific salt added.When the same K+concentration was added in different forms of KNO_(3),K_(2_SO_(4),KCl,and KH_(2)PO_(4),the changes of ionic EC contribution percentage of K^(+)were similar,but those of other anions in potassium salts varied greatly.The relative errors of estimated EC of nutrient solutions based on ionic activities were only 1.3%in horticultural experimental nutrient solution and 1.8%in Yamasaki tomato nutrient solution with different relative concentrations compared to measured EC.The relative errors of estimated EC of nutrient solutions with specific salt added were only 0.1%-0.5%compared to measured EC in two nutrient solution.Therefore,the dynamic feedback control of ionic concentration of nutrient solution could be realized by using EC measurement combined with ionic EC contribution percentage to improve the ionic quantitative control in nutrient solution.The EC control of nutrient solution in automatic irrigation system might be upgraded to ionic concentration control by using algorisms above of ionic EC contribution percentage and EC estimation to meet dynamic demands of hydroponic crops for ionic concentration in different growth stages.

Modelling of phosphorus accumulation in an aeroponic coriander crop

A model was developed for phosphorus(P)concentration over time in a closed aeroponic coriander culture.In addition,the setting and starting up of the soilless culture is described,and the measurements of electrical conductivity(EC),pH and concentration of major ions in the mixing tank are provided.By using mass balance principles,the dynamics of the nutrient concentration in the mixing tank and in the drainage solution are stated.Two series of continuous stirred tank reactors are considered for the flow structure,using a power law relationship to represent the rate of nutrient removal,considering water volume changes.Phosphorus concentration measurements were used for model fitting,and the resulting simulation is in good agreement with data.