A Study of Multi-sensor Data Fusion System Based on MAS for Nutrient Solution Measurement

For complementarity and redundancy of multi-sensor data fusion (MSDF) system,it is an effective approach for multiple components measurement.In order to measure nutrient solution on-line,a dynamic and complex system under greenhouse environment,sensors should have intelligent properties including self-calibration and self-compensation. Meanwhile,it is necessary for multiple sensors to cooperate and interact for enhancing reliability of multi-sensor system. Because of the properties of multi-agent system (MAS),it is an appropriate tool to study MSDF system.This paper proposed an architecture of MSDF system based on MAS for the multiple components measurement of nutrient solution.The sensor agent's structure and function modules are analyzed and described in detail,the formal definitions are given,too.The relations of the sensors are modeled to implement reliability diagnosis of the multi-sensor system,so that the reliability of nutrient control system is enhanced.This study offers an effective approach for the study of MSDF.

Adjusting the nutrient solution formula based on growth stages to promote the yield and quality of strawberry in greenhouse

To optimize the nutrient supply of strawberry,fertilization was reduced as much as possible on the premise of satisfying the elements needed for strawberry growth.This study put forward a modified nutrient solution formula(NM)by adjusting the ratios of N/K,K/Ca,NO_(3)^(-)-N/NH_(4)^(+)-N in vegetative growth,flowering and fruiting,and fruit expanding stages based on Yamasaki strawberry nutrient solution formula(NY).Taking the NY as the control group,the NM was verified with elevated-grown‘Ssanta’strawberry using three different substrates(Vulcanics-added substrate,Horticultural substrate,Comme rcial substrate)in greenhouse.The results indicated that under the NM treatment,strawberry plants had better photosynthesis in the vegetative growth stage and flowering and fruiting stage,and the first crop yield and total crops yield per plant also increased by 20%.Although the vegetative growth stage was longer,it entered the full fruiting stage earlier so that the maturity stage was advanced one week.Compared to strawberries grown in horticultural substrate irrigated with NY,the fruit yield per plant of‘Ssanta’strawberry grown in horticultural substrate irrigated with NM increased by 26%,and the sugar-acid ratio and vitamin C content of primary fruits reached 10.6 and 74.1 mg/100g,improving by 41%and 34%respectively.The NM based on the growth stage can optimize the element needs of strawberry in all growth and development stages and maintain the substrate’s pH stability,improving the yield and quality of‘Ssanta’strawberry under substrate cultivation.Therefore,it is recommended to use the horticultural substrate irrigated with the modified nutrient solution for the‘Ssanta’strawberries cultivation elevated in greenhouse to improve the economic benefit of strawberry cultivation.

Experimental study of ultrasonic atomizer effects on values of EC and pH of nutrient solution

The objectives of this research were to reveal how main working parameters of ultrasonic atomizers would influence key properties of the atomized nutrient solution in an aeroponics system.The Yamazaki tomato nutrient solution was selected as a nutrient example.Uniform design(UD)method U_(12)(12^(2)×13)was adopted to arrange the test.In this test,spraying time and interval time were taken as quantitative factors with 12 levels(10,20,30,40,50,60,70,80,90,100,110,and 120 min,respectively),and ultrasonic atomizer frequency was taken as qualitative factor with 3 conditions(28 kHz,107 kHz,1.7 MHz).Based on test data,two regression formulations used to predict the values ofΔEC,andΔpH of atomized Yamazaki tomato nutrient solution was established and inspected.The spraying interval time of ultrasonic atomizers had no significant effect on EC and pH of the atomized Yamazaki tomato nutrient solution;the ultrasonic atomizer frequency was more effective than spraying time on the values of EC and pH;the values of EC and pH became maximum at(f_(3),T_(1))=(1.7 MHz,120 min)and minimum at(f_(1),T_(1))=(28 kHz,10 min).It was concluded that the effect of high-frequency(1.7 MHz)ultrasonic atomizer on EC and pH of the Yamazaki tomato nutrient solution was beyond the standard value for tomato growth.Therefore,the high-frequency(1.7 MHz)ultrasonic atomizer is not suitable for aeroponics cultivation when using the Yamazaki tomato nutrient solution as aeroponics nutrient solution.

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.

Effects of nutrient solution irrigation quantity and powdery mildew infection on the growth and physiological parameters of greenhouse cucumbers

For important economic crops such as cucumbers,abiotic and biotic stress conditions have had an adverse effect.This study aimed to observe the effects of water stress and powdery mildew stress on cucumber plants.Biotic stress at two levels,B0(no powdery mildew stress)and B1(powdery mildew stress)with three fertigation requirement levels(T1:Full fertigation,T2:Moderate nutrient solution deficit,T3:Severe nutrient solution deficit).Therefore,set up six treatments of B0T1,B1T2,B0T3,B1T1,B1T2,and B1T3.Leaf gas-exchange parameter first decreases and then increases under B1T1,B1T2,and B1T2.The leaf gas exchange parameter was significantly decreased under B0T2 and B0T3.Compared to the control experiment(CK,B0T1:no disease infestation and full irrigation),the plant height of cucumber decreased by 7.55%,10.62%,15.28%,23.27%,and 35.16%,respectively,under B0T2,B0T3,B1T1,B1T2 and B1T3;the stem diameter of cucumber decreased by 9.46%,15.74%,5.47%,13.45%,and 23.72%,respectively,under B0T2,B0T3,B1T1,B1T2,and B1T3;the leaf area of cucumber decreased by 13.76%,29.96%,13.43%,38.21%,and 66.83%,respectively,under B0T2,B0T3,B1T1,B1T2,and B1T3.The root-shoot ratio of cucumber was 3.92%,3.13%,3.63%,3.84%,4.41%,and 3.82%,respectively,under the B0T1,B0T2,B0T3,B1T1,B1T2,and B1T3.Therefore,this study can provide a basis for the research on greenhouse environmental control and cucumber cultivation management.

Relationship between Tomato (Solanum lycopersicum) Nutrition and the Severity of the Vascular Fusariosis

The vascular fusariosis is one of the main obstacles in the tomato crop production. Currently, the management of the nutrient solution is presented as a control option for fusariosis, for such reason different nutrient solutions with nitrogen (N), phosphorus (P), potassium (K) and calcium (Ca) modifications;in four saladette tomato varieties Bony Best (BB), Manapal (M), Walter (W) and FLA were evaluated in this research, in order to analyze the damage caused by Fusarium oxysporum f.sp. lycopersici (FOL) severity. Tomato plants were inoculated with 3 FOL breeds, establishing a completely random design with a factorial arrangement with six repetitions. Disease’s severity was evaluated 30 days after the inoculation using levels of (0 - 4) of the methodology established by Marlatt and Correll (1988). Afterwards, a statistical analysis was done through the Kruskal Wallis test, in which it was observed that treatments 93 (Ca 207 mg∙L-1, R3, variety BB), 95 (207 mg∙L-1 Ca, R3, variety W), 81 (0Ca, R3, BB) showed less disease severity. In the foliar analysis, the best treatments were 22 (193 mg∙L-1 N, R3, M) for N, the greatest P content was treatment 94 (207 mg∙L-1 Ca, R3, M) for K treatment three and 93 (207 mg∙L-1 Ca, R3, variety BB) greatest Ca content.

Performance of tetraploid alfalfa genotypes as exposed to aluminum toxicity

A study was carried out to evaluate the development of 12 tetraploid alfalfa cultivars exposed to Al toxicity in nutrient solution. Newly germinated seedlings of cultivars Alfa 200, Alto, Araucana, Costera, Crioula, Esmeralda, Falcon, F-708, Rio, Romagnola, Valley Plus, and Victoria, were exposed to either 0, 4, 8 or 12 mg·L-1 Al3+. Plants were analyzed regarding root length (RL) and dry matter (RDM), aerial part length (APL), and dry matter (APDM), hypocotyl length (HypL) and dry matter (HypDM), epicotyl length (EpiL) and dry matter (EpiDM), and petiole length (PetL), and dry matter (PetDM). Results indicated that, although all genotypes exhibited detectable sensitivity to such a stress, cvs. Crioula, Victoria and Alpha-200 were tolerant to 4 mg·L-1 Al3+ toxicity. It was also concluded that Al3+ levels up to the 4 mg·L-1 will be effective for screening tetraploid alfalfa genotypes regarding this type of stress, when evaluations are made in nutrient solution. Finally, RL is the most suitable variable for conducting such evaluations, but all variables related to dry matter in the aerial part are also recommended.

Multielemental Microanalysis in Root and Leaves, Growth and Biomass in Tomato Seedling in Response to Ca Levels and Induction of Stress: Non-Destructive Spectroscopy

Tomatoes are one of the main vegetables in the food industry that are consumed fresh and processed. A multi-element microanalysis was performed with the use of scanning electron microscopy (SEM) in conjunction with energy dispersion spectroscopy (EDS), to see changes in nutrient concentration in roots and leaves, as well as fresh and dry biomass in tomato seedlings. Exposed in nutrient solution (NS) with different levels of Ca (control, 25, 50 and 100 mM). The root was put in also to H2O2 for 8 hours to observe the changes that occurred. It was observed that NS with 100 mM Ca in fresh stem biomass and fresh leaf biomass increased by 25% and 38% compared to the control. It was observed that the NS with 100 and 50 mM of Ca, the content of Ca and Cl in foliar tissue increased by 34.50% and 13.15% compared to the control. Treatment with H2O2 and with 25 and 100 mM of Ca at NS increased the height of the seedling and fresh leaf bio-mass by 19.75% and 60.80% compared to the control. The treatment with H2O2 and with the different levels of Ca in the NS increased the content of C, P, K, Ca and Cl in the leaf tissue. Only S was significant for the control. Treatment with H2O2 and 100 mM Ca in the NS increased Ca and Mg by 83.48% and 40.47% for the root compared to the control. The K and Cl in the root was higher in the control treatment by 47.61% and 55% respect to the highest level of Ca. It is concluded that multielemental microanalysis is a powerful, non-destructive, fast and accurate tool for the determination of plant nutrients. Also, it is applicable for the areas like horticulture, physiology and agronomy.

Effects of Non-Conventional Substrate and NPK Fertilizer on Cassava Plantlets Acclimatization for Plant Material Production

The adaptation of cassava plantlets to natural conditions remains the main obstacle in the process of free virus plantlets production. In this study, cassava plantlets acclimatization was assessed by pre-acclimatization, height of acclimated plantlets, substrate, and nutrient watering solution. The results revealed that pre-acclimatization gave a high survival rate (61.9%) whereas the direct tunnel acclimatization was conducted to low rate (27.31%) of plantlets. Furthermore, the height of plantlets influenced significantly (p < 0.05) their survival rate with best survival rate observed on plantlet height from 1 cm to 5 cm. There was no significant difference between the substrates used and watering solutions. However, the Sawdust substrate gave a high survival rate (46.67%) and better phylogenesis (1.8) in the variety RB 89509. Likewise, plantlets treated with NPK nutrient watering solutions (20-10-10) had a better survival rate (48.57%), better phylogenesis (2.125) with the variety RB 89509 and better growth in height (1.18 cm) with the variety BF92/0267. These findings constitute a database for the establishment of the technical itinerary for the acclimatization of cassava plantlets.

Rooting Potential of Mini-Cuttings for the Production of Potato Plantlets

The production of mini-tubers under soilless cultivation system increased the availability of pathogen-free seed potatoes. The objective of this study was to evaluate the rooting capability of mini-cuttings of potato clones as a function of the irrigation solution and the physiological age of the mother plant, under soilless cultivation system. Potato mini-cuttings were collected from young and mature plants of the cultivars Asterix and Macaca and the advanced clone SMINIA 793101-3. The young plants were newly acclimatized individuals and the mature plants were at the stage of producing mini-tubers. In the first experiment, mini-cuttings originating from summer pruning of mature plants were grown under closed soilless cultivation system irrigated with a nu- trient solution developed for the production of potato mini-tubers and a solution comprised of tap water only. The experiment was conducted in a 3 × 2 factorial arrangement (clones and irrigation solutions) in the complete random design with four replicates of 15 mini-cuttings. In the second experiment, the young and mature mini-cuttings were established under a closed soilless cultivation system irrigated with nutrient solution. The experiment was conducted in a 3 × 2 factorial arrangement (clones and physiological age of the mother plant) in the complete random design with four replicates of 15 mini-cuttings. In both experiments, the percentage of rooting and survival of mini-cuttings, number of roots and length of the longest root were assessed at 21 days of cultivation. Potato mini-cuttings can be rooted under closed soilless cultivation system irrigated with nutrient solution or tap water. Mini-cuttings of young plants have higher rooting capability compared to the ones taken from mature plants. The loss of rooting capability depends upon the potato cultivar.