Temperature, as an important feature of hydroponic nutrient solution, is closely related to dissolved oxygen content of nutrient solution and growth status of plant roots. How to precisely adjust the temperature of nu...Temperature, as an important feature of hydroponic nutrient solution, is closely related to dissolved oxygen content of nutrient solution and growth status of plant roots. How to precisely adjust the temperature of nutrient solution is the key to obtain high quality and high yield of hydroponic vegetables over summer. With Lactuca sativa vat. crispa 'Luosheng No.3' as the test material, the effect of chiller cooling technology on the temperature of nutrient solution, as well as on the yield and quality of Luosheng No.3, in over-summer hydroponic cultivation was studied. The results showed that the chiller cooling technology controlled the nutrient solution temperature in a reasonable range ((20 ± 1)℃) and promoted the growth and dry matter accumulation of Luosheng No.3, instead of affecting the quality. In short, the chiller cooling technology is applicable to the temperature regulation of nutrient solu- tion in hydroponics over summer.展开更多
Using simulated soil column experiments, the effects of different dosages and ratios of KCI and MgCI2 mixture on salinization nutrient ions in the secondary salinization soil which had 3 years of planting were studied...Using simulated soil column experiments, the effects of different dosages and ratios of KCI and MgCI2 mixture on salinization nutrient ions in the secondary salinization soil which had 3 years of planting were studied, with the aim to provide the theory basis for the remediation of secondary salinization soil. Results showed that the content of soil K-, Mg2+, CI- and the total salinity were increased, with the increasing concentrations of nutrient solution, while Na+, Ca2+ and HCO3- contents were reduced. Compared with originals oil, soil K+, Na+, Ca2+, Mg2+, CI- and total soil salinity were decreased, and HCO3- and SO42 were increased. In terms of the variation of soil total charge, the change ranges in 1:1 treatment varied small, but the residual of soil cationic decreased with increasing application of K+ in the 2:1 treatment. It could be concluded that balanced and low application fertilizer could alleviate the soil saline, decrease the soil nutrition leaching and improve the balance among ions, while excess fertilization could accelerate the imbalance of zwitterions.展开更多
[Objectives] This study was conducted to investigate the effect of organic nutrient solution on litchi quality. [Methods] Different concentrations of organic nutrient solutions were sprayed on litchi leaves to study t...[Objectives] This study was conducted to investigate the effect of organic nutrient solution on litchi quality. [Methods] Different concentrations of organic nutrient solutions were sprayed on litchi leaves to study their effects on amino acid contents in the fruit of litchi cultivar "Qinzhouhongli". [Results] The results showed that the organic nutrient solution could significantly promote the growth of litchi fruit at various development stages and improve fruit quality by spraying the organic nutrient solution for 3 times with a dilution concentration of 500-1 500 times during fruit development(at an interval of 15 d) of litchi. It could increase the total essential amino acid, total semi-essential amino acid, lysine, phenylalanine, threonine, methionine, valine, leucine, histidine, arginine, aspartic acid, glycine, serine, proline, alanine and tyrosine contents. Spraying the organic nutrient solution with a dilution concentration of 1 000 times achieved the best effect of promoting the growth and improving quality of litchi fruit. [Conclusions] This study provides a theoretical basis for high-quality production and nutritional quality evaluation of litchi and the development of functional processed litchi products.展开更多
Based on the limitations of traditional plant nutrient solution detection, a ZigBee plant nutrient solution detection system based on CC2530 was developed. This system uses CC2530 as the main control chip, DS18B20 as ...Based on the limitations of traditional plant nutrient solution detection, a ZigBee plant nutrient solution detection system based on CC2530 was developed. This system uses CC2530 as the main control chip, DS18B20 as the temperature sensor for temperature acquisition, PH electrode sensor for PH value acquisition. The experiment shows that this wireless control system equipped with temperature and pH detection sensor collects and samples the main nutrient solution parameters through the main controller, performs wireless communication transmission and terminal communication, and realizes the intelligent detection of plant nutrient solution parameters. This technique of applying wireless sensor network technology to plant factories greatly improves the reliability and stability of the nutrient monitoring system.展开更多
The impacts of pH on roots growth of sugarcane seedlings were explored by a pot test. The nutrient solution with three pH levels, Le., 5.0, 7.0 and 8.5 were applied to culture five combination seedlings, including A ...The impacts of pH on roots growth of sugarcane seedlings were explored by a pot test. The nutrient solution with three pH levels, Le., 5.0, 7.0 and 8.5 were applied to culture five combination seedlings, including A (RB85-5156 × YR05-407), B (YR06-3501 ×Tolodo), C (YT94-128 × GZ75-65), D (ROC6 × YR05-733) and E (VMC87-95 ×YR05-171). The result indicated that root length, root surface, root volume and root diameter were all in the largest in B combination with solution pH= 7.0, and the root length, root surface, root volume were in the largest in combination A, C, D and E with solution pH=8.5. Root activity in combination C, D and E were in the highest with solution pH=5.0, while it was in the highest for combination B when pH=7.0. In general, the root growth and morphology in all five combinations were better in the solutions with pH of 7.0 and 8.5.展开更多
The coupling effect of nutrient solution EC (electrical conductivity) levels and CR (circulation rate) on the morphology and quality, in hydroponically grown lettuce was assessed. Lettuce was grown at 5 treatments...The coupling effect of nutrient solution EC (electrical conductivity) levels and CR (circulation rate) on the morphology and quality, in hydroponically grown lettuce was assessed. Lettuce was grown at 5 treatments fi'om High EC & Low CR to Low EC & High CR. The environmental parameters were controlled in a 20 m^2 plant factory during the hydroponic cultivation with the following values: irradiated by blue and red light-emitting diode lighting with PPFD (photosynthetic photon flux density) value of 150 mol·m^-2·s^-1 for 16 hours per day; Temperature was maintained at 22.0 ℃ during the photoperiod and 16.0 ℃ in dark cycle. The results demonstrate that growing lettuce can be adopted using nutrient solution with lower EC levels and higher CR. The results also indicate that the effect of bi-directional coupled EC and CR resulted in expansion of root length but reducing the root biomass. Nitrate content was significantly reduced.展开更多
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 ...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.展开更多
A nutrition solution experiment was conducted over two months to investigate the response of vegetable crops to high concentrations of ammonium, using lettuce (Lactuca sativa L. cv. Angustana Irish) as a test crop. ...A nutrition solution experiment was conducted over two months to investigate the response of vegetable crops to high concentrations of ammonium, using lettuce (Lactuca sativa L. cv. Angustana Irish) as a test crop. Ammonium concentrations were designed in 5 levels, ranging from 12 mmol N L^-1 to 22 mmol N L^-1 and local tap water was used as water source. At the first culture stage (0-9 days), lettuce plants maintained normal growth while the lettuce roots were increasingly impaired. During the subsequent three stages the root structure was greatly damaged, and roots became brown or black through continuous supply of high concentration of ammonium. However, there was no obvious reduction of the aboveground biomass of the plants in the high ammonium treatments compared to those supplied with nitrate alone. In contrast to results obtained in another experiment from us with distilled water, the detrimental effect of high ammonium concentration on lettuce growth was greatly alleviated. Based on the results, it was postulated that the small amount of nitrate and the higher amount of bicarbonate existed in the tap water might mitigate the adverse effects of high ammonium N. The higher bicarbonate content in water and soil has usually been regarded as a major constraint factor limiting plant growth in calcareous soil areas. However, the reaction of bicarbonate to ammonium might produce positively interactive effect on reduction of both damages. The lettuce plants grown in ammonium solutions took up less P, K, Fe, Mn and Cu and more Ca than those grown in the nitrate nutrient solution. In conclusion, the results indicated that the N form imposed an obvious influence on absorption of cations and anions. Supplying ammonium-N stimulated transport of Ca, Mg and Mn to shoots of lettuce.展开更多
In aeroponic cultivation the nutrient solution is an essential component to achieve good production results. And nitrogen is the main constituent element of the nutrient solution and essential element in plant nutriti...In aeroponic cultivation the nutrient solution is an essential component to achieve good production results. And nitrogen is the main constituent element of the nutrient solution and essential element in plant nutrition. Therefore, the management and monitoring nutrient solution and existing nitrogen is fundamental. The experiment shows that three modes of replacing the nutrient solution and three initial pH values and their interaction significantly influenced the fresh weight and dry matter of lettuce. The highest values of fresh and dry weight were recorded in the fifth treatment where there is an interaction between pH 6 and the mode of replacing half of the nutrient solution. The consumption rate of nitrate nitrogen (NOa-N), ammonium nitrogen (NH4-N) and gross nitrogen (GN) was higher during stage 1 (10 days after transplanting), especially for the mode of complete replacing nutrient solution.展开更多
Unstable pH of nutrient solution in hydroponic systems is a major obstacle to production.To simplify the management of nutrient solution pH and attenuate negative effects of pH on plant growth,this study investigated ...Unstable pH of nutrient solution in hydroponic systems is a major obstacle to production.To simplify the management of nutrient solution pH and attenuate negative effects of pH on plant growth,this study investigated the effect of different buffer salt additions on nutrient solution pH,ion uptake,growth and photosynthesis of Yamazaki lettuce,with the equivalent concentrations of macro-element unchanged.The results indicated that the pH of nutrient solution was buffered to varying degrees by the 2 mol/L HCO_(3)^(-),1 mol/L HCO_(3)^(-),and 0.33 mol/L HPO_(4)^(2-)The 0.33 mol/L HPO_(4)^(2-)treatment fluctuated most with a pH of 1.74 units,while the addition of HCO_(3)^(-)buffered nutrient solution pH was better,with higher pH values(7.2-7.7).The CK-pH control solution,1 mol/L HCO_(3)^(-)and 0.33 mol/L HPO_(4)^(2-)treatments all promoted the uptake of ion and then the growth of lettuce was better in comparison with the CK-pH no adjustment treatment,while the 2 mol/L HCO_(3)^(-)treatment inhibited K uptake and reduced the availability of Fe,the shoot and root fresh weight of lettuce decreased by 21.3%and 10.1%,respectively.In addition,although the chlorophyll content and net photosynthetic rate under 1 mol/L HCO_(3)^(-)and 0.33 mol/L HPO_(4)^(2-)treatments were significantly lower than the CK-pH control solution treatment,there were no significant differences in leaf length and leaf number of lettuce among them,and shoot fresh weight per plant was 83.09,82.95,and 78.92 g,respectively.In conclusion,adding 1 mol/L HCO_(3)^(-)to the nutrient solution in a single dosage not only buffered the pH of nutrient solution better but also promoted ion uptake,it had no negative effects on the growth,photosynthesis and ion uptake of hydroponic lettuce in comparison with the CK-pH control solution treatment.Therefore,1 mol/L HCO_(3)^(-)can be used as a buffer during the growth of hydroponic lettuce and reduce frequent addition of acids or alkalis,and then simplify the management of nutrient solution for hydroponic lettuce production.展开更多
According to the physiological and anatomical characteristics of small intestine,neglecting the effect of its motility on the distribution and absorption of drug and nutrient,Y.Miyamoto et al.proposed a model of two-d...According to the physiological and anatomical characteristics of small intestine,neglecting the effect of its motility on the distribution and absorption of drug and nutrient,Y.Miyamoto et al.proposed a model of two-dimensional laminar flow in a circular porous tube with permeable wall and calculated the concentration profile of drugby numerical analysis.In this paper,we give a steady-state analytical solution of the above model including deactivationterm.The obtained results are in agreement with the results of their numerical analysis. Moreover the analytical solution presented in this paper reveals the relation among the physiological parameters of the model and describes the basic absorption rule of drug and nutrient through the intestinal wall and hence pro- vides a theoretical basis for determining the permeability and reflection coefficient through in situ experiments.展开更多
Water availability is a fundamental condition for sustainable agriculture. However, a satisfactory water condition is not always possible in terms of quantity and quality in certain regions, such as the Brazilian semi...Water availability is a fundamental condition for sustainable agriculture. However, a satisfactory water condition is not always possible in terms of quantity and quality in certain regions, such as the Brazilian semi-arid region. Thus, the purpose of this extremely important research was to evaluate the growth of cv. All Big with six combinations of wastewater plus saline (WW + SW) and two nutrient solution percentages, in a low-cost hydroponic system. The experiment was carried out in a greenhouse at the Department of Agricultural Engineering at Federal University of Campina Grande. A completely randomized experimental design was used, with treatments arranged in a factorial scheme (6 × 2), with 5 replications, being the treatments composed by the combination of six proportions of wastewater with saline water (50%/50%;60%/40%;70%/30%;80%/20%;90%/10%;100% of wastewater) and two nutrient solution concentration (80% and 100%), totalizing 60 experimental units. The biometric variables were analyzed at 55 and 96 days after sowing, namely: plant height (PH), stem diameter (SD), leaf number (LN) and leaf area (LA). The interaction between the concentration of the nutrient solution and the ratio of the saline water with wastewater was influenced in the behavior of peppers (cv. All Big) biometric variables. The nutrient solution prepared at 80% of its normal concentration had better performance in the development of plants when mixed with the proportions of water containing more wastewater. The proportion 30% saline water and 70% wastewater (30/70) with concentration of 80% of the nutrient solution obtained better satisfactory results in the studied biometric variables.展开更多
基金Supported by Science and Technology Innovative Leading Fund of Ningxia Academy of Agriculture and Forestry Sciences(NKYZ-16-1101)~~
文摘Temperature, as an important feature of hydroponic nutrient solution, is closely related to dissolved oxygen content of nutrient solution and growth status of plant roots. How to precisely adjust the temperature of nutrient solution is the key to obtain high quality and high yield of hydroponic vegetables over summer. With Lactuca sativa vat. crispa 'Luosheng No.3' as the test material, the effect of chiller cooling technology on the temperature of nutrient solution, as well as on the yield and quality of Luosheng No.3, in over-summer hydroponic cultivation was studied. The results showed that the chiller cooling technology controlled the nutrient solution temperature in a reasonable range ((20 ± 1)℃) and promoted the growth and dry matter accumulation of Luosheng No.3, instead of affecting the quality. In short, the chiller cooling technology is applicable to the temperature regulation of nutrient solu- tion in hydroponics over summer.
基金Supported by the Science and Technology Development Project in Weifang(2015GX078 and 2013YD182)~~
文摘Using simulated soil column experiments, the effects of different dosages and ratios of KCI and MgCI2 mixture on salinization nutrient ions in the secondary salinization soil which had 3 years of planting were studied, with the aim to provide the theory basis for the remediation of secondary salinization soil. Results showed that the content of soil K-, Mg2+, CI- and the total salinity were increased, with the increasing concentrations of nutrient solution, while Na+, Ca2+ and HCO3- contents were reduced. Compared with originals oil, soil K+, Na+, Ca2+, Mg2+, CI- and total soil salinity were decreased, and HCO3- and SO42 were increased. In terms of the variation of soil total charge, the change ranges in 1:1 treatment varied small, but the residual of soil cationic decreased with increasing application of K+ in the 2:1 treatment. It could be concluded that balanced and low application fertilizer could alleviate the soil saline, decrease the soil nutrition leaching and improve the balance among ions, while excess fertilization could accelerate the imbalance of zwitterions.
基金Supported by National Natural Science Foundation of China(31260461)2017 Guangxi Higher Education Undergraduate Teaching Reform Project2017JGB132)+1 种基金Nanning Test Station of Litchi and Longan Innovation Team of National Modern Agriculture Technology System in Guangxi(nycytxgxcxtd-03-12-3)Earmarked Fund for China Agriculture Research System(CARS-33-09)
文摘[Objectives] This study was conducted to investigate the effect of organic nutrient solution on litchi quality. [Methods] Different concentrations of organic nutrient solutions were sprayed on litchi leaves to study their effects on amino acid contents in the fruit of litchi cultivar "Qinzhouhongli". [Results] The results showed that the organic nutrient solution could significantly promote the growth of litchi fruit at various development stages and improve fruit quality by spraying the organic nutrient solution for 3 times with a dilution concentration of 500-1 500 times during fruit development(at an interval of 15 d) of litchi. It could increase the total essential amino acid, total semi-essential amino acid, lysine, phenylalanine, threonine, methionine, valine, leucine, histidine, arginine, aspartic acid, glycine, serine, proline, alanine and tyrosine contents. Spraying the organic nutrient solution with a dilution concentration of 1 000 times achieved the best effect of promoting the growth and improving quality of litchi fruit. [Conclusions] This study provides a theoretical basis for high-quality production and nutritional quality evaluation of litchi and the development of functional processed litchi products.
文摘Based on the limitations of traditional plant nutrient solution detection, a ZigBee plant nutrient solution detection system based on CC2530 was developed. This system uses CC2530 as the main control chip, DS18B20 as the temperature sensor for temperature acquisition, PH electrode sensor for PH value acquisition. The experiment shows that this wireless control system equipped with temperature and pH detection sensor collects and samples the main nutrient solution parameters through the main controller, performs wireless communication transmission and terminal communication, and realizes the intelligent detection of plant nutrient solution parameters. This technique of applying wireless sensor network technology to plant factories greatly improves the reliability and stability of the nutrient monitoring system.
基金Supported by National Modern Agriculture Industry Technology System Construction Project(CARS-20-1-1)Yunnan Key New Product Development and Planning Project(2011BB005)Yunnan Key New Product Development and Planning(2012BB014)~~
文摘The impacts of pH on roots growth of sugarcane seedlings were explored by a pot test. The nutrient solution with three pH levels, Le., 5.0, 7.0 and 8.5 were applied to culture five combination seedlings, including A (RB85-5156 × YR05-407), B (YR06-3501 ×Tolodo), C (YT94-128 × GZ75-65), D (ROC6 × YR05-733) and E (VMC87-95 ×YR05-171). The result indicated that root length, root surface, root volume and root diameter were all in the largest in B combination with solution pH= 7.0, and the root length, root surface, root volume were in the largest in combination A, C, D and E with solution pH=8.5. Root activity in combination C, D and E were in the highest with solution pH=5.0, while it was in the highest for combination B when pH=7.0. In general, the root growth and morphology in all five combinations were better in the solutions with pH of 7.0 and 8.5.
文摘The coupling effect of nutrient solution EC (electrical conductivity) levels and CR (circulation rate) on the morphology and quality, in hydroponically grown lettuce was assessed. Lettuce was grown at 5 treatments fi'om High EC & Low CR to Low EC & High CR. The environmental parameters were controlled in a 20 m^2 plant factory during the hydroponic cultivation with the following values: irradiated by blue and red light-emitting diode lighting with PPFD (photosynthetic photon flux density) value of 150 mol·m^-2·s^-1 for 16 hours per day; Temperature was maintained at 22.0 ℃ during the photoperiod and 16.0 ℃ in dark cycle. The results demonstrate that growing lettuce can be adopted using nutrient solution with lower EC levels and higher CR. The results also indicate that the effect of bi-directional coupled EC and CR resulted in expansion of root length but reducing the root biomass. Nitrate content was significantly reduced.
文摘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.
基金This is part work of the project(30230230)supported by the National Natural Science Foundation of China(NFSC).
文摘A nutrition solution experiment was conducted over two months to investigate the response of vegetable crops to high concentrations of ammonium, using lettuce (Lactuca sativa L. cv. Angustana Irish) as a test crop. Ammonium concentrations were designed in 5 levels, ranging from 12 mmol N L^-1 to 22 mmol N L^-1 and local tap water was used as water source. At the first culture stage (0-9 days), lettuce plants maintained normal growth while the lettuce roots were increasingly impaired. During the subsequent three stages the root structure was greatly damaged, and roots became brown or black through continuous supply of high concentration of ammonium. However, there was no obvious reduction of the aboveground biomass of the plants in the high ammonium treatments compared to those supplied with nitrate alone. In contrast to results obtained in another experiment from us with distilled water, the detrimental effect of high ammonium concentration on lettuce growth was greatly alleviated. Based on the results, it was postulated that the small amount of nitrate and the higher amount of bicarbonate existed in the tap water might mitigate the adverse effects of high ammonium N. The higher bicarbonate content in water and soil has usually been regarded as a major constraint factor limiting plant growth in calcareous soil areas. However, the reaction of bicarbonate to ammonium might produce positively interactive effect on reduction of both damages. The lettuce plants grown in ammonium solutions took up less P, K, Fe, Mn and Cu and more Ca than those grown in the nitrate nutrient solution. In conclusion, the results indicated that the N form imposed an obvious influence on absorption of cations and anions. Supplying ammonium-N stimulated transport of Ca, Mg and Mn to shoots of lettuce.
文摘In aeroponic cultivation the nutrient solution is an essential component to achieve good production results. And nitrogen is the main constituent element of the nutrient solution and essential element in plant nutrition. Therefore, the management and monitoring nutrient solution and existing nitrogen is fundamental. The experiment shows that three modes of replacing the nutrient solution and three initial pH values and their interaction significantly influenced the fresh weight and dry matter of lettuce. The highest values of fresh and dry weight were recorded in the fifth treatment where there is an interaction between pH 6 and the mode of replacing half of the nutrient solution. The consumption rate of nitrate nitrogen (NOa-N), ammonium nitrogen (NH4-N) and gross nitrogen (GN) was higher during stage 1 (10 days after transplanting), especially for the mode of complete replacing nutrient solution.
基金funded by the Beijing Capital Agriculture Group Self-Supporting Science and Technology Projects[Grant No.SNSPKJ 2022(01)]Chinese Universities Scientific Fund(Grant No.2023TC087).
文摘Unstable pH of nutrient solution in hydroponic systems is a major obstacle to production.To simplify the management of nutrient solution pH and attenuate negative effects of pH on plant growth,this study investigated the effect of different buffer salt additions on nutrient solution pH,ion uptake,growth and photosynthesis of Yamazaki lettuce,with the equivalent concentrations of macro-element unchanged.The results indicated that the pH of nutrient solution was buffered to varying degrees by the 2 mol/L HCO_(3)^(-),1 mol/L HCO_(3)^(-),and 0.33 mol/L HPO_(4)^(2-)The 0.33 mol/L HPO_(4)^(2-)treatment fluctuated most with a pH of 1.74 units,while the addition of HCO_(3)^(-)buffered nutrient solution pH was better,with higher pH values(7.2-7.7).The CK-pH control solution,1 mol/L HCO_(3)^(-)and 0.33 mol/L HPO_(4)^(2-)treatments all promoted the uptake of ion and then the growth of lettuce was better in comparison with the CK-pH no adjustment treatment,while the 2 mol/L HCO_(3)^(-)treatment inhibited K uptake and reduced the availability of Fe,the shoot and root fresh weight of lettuce decreased by 21.3%and 10.1%,respectively.In addition,although the chlorophyll content and net photosynthetic rate under 1 mol/L HCO_(3)^(-)and 0.33 mol/L HPO_(4)^(2-)treatments were significantly lower than the CK-pH control solution treatment,there were no significant differences in leaf length and leaf number of lettuce among them,and shoot fresh weight per plant was 83.09,82.95,and 78.92 g,respectively.In conclusion,adding 1 mol/L HCO_(3)^(-)to the nutrient solution in a single dosage not only buffered the pH of nutrient solution better but also promoted ion uptake,it had no negative effects on the growth,photosynthesis and ion uptake of hydroponic lettuce in comparison with the CK-pH control solution treatment.Therefore,1 mol/L HCO_(3)^(-)can be used as a buffer during the growth of hydroponic lettuce and reduce frequent addition of acids or alkalis,and then simplify the management of nutrient solution for hydroponic lettuce production.
基金The project supported by NSF of Shandong Province
文摘According to the physiological and anatomical characteristics of small intestine,neglecting the effect of its motility on the distribution and absorption of drug and nutrient,Y.Miyamoto et al.proposed a model of two-dimensional laminar flow in a circular porous tube with permeable wall and calculated the concentration profile of drugby numerical analysis.In this paper,we give a steady-state analytical solution of the above model including deactivationterm.The obtained results are in agreement with the results of their numerical analysis. Moreover the analytical solution presented in this paper reveals the relation among the physiological parameters of the model and describes the basic absorption rule of drug and nutrient through the intestinal wall and hence pro- vides a theoretical basis for determining the permeability and reflection coefficient through in situ experiments.
文摘Water availability is a fundamental condition for sustainable agriculture. However, a satisfactory water condition is not always possible in terms of quantity and quality in certain regions, such as the Brazilian semi-arid region. Thus, the purpose of this extremely important research was to evaluate the growth of cv. All Big with six combinations of wastewater plus saline (WW + SW) and two nutrient solution percentages, in a low-cost hydroponic system. The experiment was carried out in a greenhouse at the Department of Agricultural Engineering at Federal University of Campina Grande. A completely randomized experimental design was used, with treatments arranged in a factorial scheme (6 × 2), with 5 replications, being the treatments composed by the combination of six proportions of wastewater with saline water (50%/50%;60%/40%;70%/30%;80%/20%;90%/10%;100% of wastewater) and two nutrient solution concentration (80% and 100%), totalizing 60 experimental units. The biometric variables were analyzed at 55 and 96 days after sowing, namely: plant height (PH), stem diameter (SD), leaf number (LN) and leaf area (LA). The interaction between the concentration of the nutrient solution and the ratio of the saline water with wastewater was influenced in the behavior of peppers (cv. All Big) biometric variables. The nutrient solution prepared at 80% of its normal concentration had better performance in the development of plants when mixed with the proportions of water containing more wastewater. The proportion 30% saline water and 70% wastewater (30/70) with concentration of 80% of the nutrient solution obtained better satisfactory results in the studied biometric variables.