Concentration In Nutrient Solution Research Articles

Seed potato minituber production in an aeroponic system under tropical conditions: electrical conductivity and plant density

Most seed potatoes in Brazil are produced in beds, pots or boxes containing substrate, but the yields are low. Aeroponic systems are one strategy for increasing the yield. However, the concentration of nutrient solutions, managed by varying the electrical conductivity (EC), is of upmost importance and can alter plant responses. Plant density is another important factor for obtaining high yields. The objective of this study was thus to determine the effect of nutrient-solution EC and plant density on plant and seed potato production in aeroponic system. The experimental design was a randomized block with a split-plot design and four replicates, with plots for EC and subplots for plant density. Two potato cultivars were tested. The best ECs for “Agata” and “Asterix” were 2.1 and 1.7 dS m−1, respectively. The highest plant density (100 plants m−2) for both cultivars produced the highest minituber yield and economic feasibility.

Growth and Fruit Biochemical Characteristics of Three Strawberry Genotypes under Different Potassium Concentrations of Nutrient Solution

Abstract A nutrient solution experiment was performed to evaluate the growth, yield and fruit biochemical characteristics of strawberry under different potassium levels of nutrient solution. Potassium concentrations including 235 (control), 350, 450 and 600 mg L-1 were applied to three strawberry genotypes of Camarosa, Selva and Parus under hydroponic culture. In the three genotypes, the maximum leaf area was observed at 350 mg L-1 K, and the maximum shoot fresh weight was either at 350 mg L-1 (in Camarosa and Parus) or at 400 mg L-1 (in Selva). In Selva, higher yield was produced by higher K concentrations than control (17-33%) and in Camarosa, the maximum yield was produced at 350 mg L-1 (16%), whereas fruit yield in Parus was not affected by K concentrations. In Selva and Parus application of 350 mg L-1 potassium produced more fruits than control. The maximum fruit vitamin C content in Camarosa and Selva was at 350 mg L-1, and in Parus at 450 mg L-1, while the significant lowest in three genotypes was at 600 mg L-1. Fruit titratable acidity and pH in Camarosa and Selva, and fruit TSS in Parus were not affected by K levels. Fruit total soluble solids (TSS) in Camarosa and Selva were maximum in 350 and 450 mg L-1. Increasing K concentrations of nutrient solution increased leaf and fruit K concentration than control. The results indicate that overall plant growth and fruit quality of three strawberry genotypes were increased by 350 mg L-1 potassium, while application of 600 mg L-1 reduced most traits than control. The Selva genotype had also a better response to higher concentration of K than two other genotypes.

Effects of Nutrient Solution Concentration and Daily Light Integral on Growth and Nutrient Concentration of Several Basil Species in Hydroponic Production

Our objective was to quantify the effect of mineral nutrient concentration of a nutrient solution on the growth of basil species and cultivars grown under high and low photosynthetic daily light integrals (DLIs). Sweet basil (Ocimum basilicum ‘Nufar’), lemon basil (O. ×citriodorum ‘Lime’), and holy basil (O. tenuiflorum ‘Holy’) seedlings were transplanted into nutrient-film technique (NFT) systems with different nutrient solution electrical conductivities (EC; 0.5, 1.0, 2.0, 3.0, or 4.0 dS·m–1) in greenhouses with a low (≈7 mol·m–2·d–1) or high (≈15 mol·m–2·d–1) DLI. Although nutrient solution EC did not affect growth and morphology, increasing DLI did. For example, when sweet basil was grown under a high DLI, the fresh and dry weight, height, and node number increased by 144%, 178%, 20%, and 18%, respectively, compared with plants grown under the low DLI, and branching was also stimulated. In contrast, DLI had little effect on tissue nutrient concentration, although nutrient solution did. Most tissue nutrient concentrations increased with increasing EC, with the exception of Mg and Ca. For example, N in sweet basil increased by 0.6% to 0.7% whereas Mg decreased by 0.2% as EC increased from 0.5 to 4.0 dS·m–1. Across treatments and basil species, tissue nutrient concentrations were generally within recommended ranges with no visible deficiencies. Based on our results, nutrient solution concentrations for hydroponic basil production can be selected based on factors such as other species grown in the same solution or by reducing fertilizer inputs.

Depicting the physiological and ultrastructural responses of soybean plants to Al stress conditions

Aluminium (Al) is a toxic element for plants living in soils with acidic pH values, and it causes reductions in the roots and shoots development. High Al concentrations can cause physiological and structural changes, leading to symptoms of toxicity in plant tissue. The aim of this study was to describe the Al toxicity in soybean plants through physiological, nutritional, and ultrastructure analyses. Plants were grown in nutrient solution containing increasing Al concentrations (0; 0.05; 0.1; 1.0, 2.0 and 4.0 mmol L−1). The Al toxicity in the soybean plants was characterized by nutritional, anatomical, physiological, and biochemical analyses. The carbon dioxide assimilation rates and stomatal conductance were not affected by the Al. However, the capacity for internal carbon use decreased, and the transpiration rate increased, resulting in increased root biomass at the lowest Al concentration in the nutrient solution. The soybean plants exposed to the highest Al concentration exhibited lower root and shoot biomass. The nitrate reductase and urease activities decreased with the increasing Al concentration, indicating that nitrogen metabolism was halted. The superoxide dismutase and peroxidase activities increased with the increasing Al availability in the nutrient solution, and they were higher in the roots, showing their role in Al detoxification. Despite presenting external lesions characterized by a damaged root cap, the root xylem and phloem diameters were not affected by the Al. However, the leaf xylem diameter showed ultrastructural alterations under higher Al concentrations in nutrient solution. These results have contributed to our understanding of several physiological, biochemical and histological mechanisms of Al toxicity in soybean plants.

تأثير إضافة المخصبات الأحيائية والرش بالمحلول المغذي كاليبور في نمو شتلات الرمان صنف Wonderful

نفذت التجربة في أحد الحقول التابعة لقسم البستنة وهندسة الحدائق /كلية الزراعة - جامعة ديالي للمدة 2016- 2- 24 لغاية 2017- 6- 1على شتلات رمان صنف Wonderful بهدف معرفة تأثير المعاملة بخليط من المخصبــات الأحيائيــة والرش بالمحلول المغذي كاليبور في صفات النمو الخضري لشتلات الرمان صنف Wonderful. استخدمت شتلات رمان بعمر سنتين متساوية الحجم قدر الامكان وأضيف المخصب الأحيائي الحاوي على بكتريا من النوعين Azospirillum brasilense وPseudomonas flourescense إلى وسط النمو المخصص لكل شتلة بتراكيز0، 10، 20غم. نبات- 1 بتاريخ 2016/2/24 ورشت الشتلات بأربعة تراكيز من المحلول المغذي (كاليبور) (7، 5، 3. 5، 0 مل. لتر- 1)ونفذت التجربة باستخدام تصميم القطاعات كاملة التعشية(RCBD ويمكن تلخيص نتائج التجربة بالآتي: 1- أدت إضافة المخصب الاحيائــي إلى زيادة معنوية في جميع معايير النمو الخضرية للشتلات قياساً بمعاملة المقارنة وأعطى المستوى الثالث من المخصب أعلى القيم لمتوسط الزيادة في قطر الساق الرئيس وطوله والمحتوى النسبي للكلوروفيل في الأوراق عند كلا موسمي النمو. أدى الرش بالمحلول المغذي كاليبور إلى إحداث زيادة معنوية في جميع معايير النمو الخضرية ولكلا موسمـــي النمو، ولم يختلف التركيز الثاني والثالث من المحلول عن بعضهما معنويا في جميع الصفات الخضرية ولكلا موسمي النمو (باستثناء صفة قطر الساق في الموسم الثاني)، وأزداد التأثير الايجابي في الصفات السابقة عند تداخل العاملين (المخصب الأحيائي والمحلول المغـذي) وحقق التداخل بين التركيزين الثاني والثالث من المحلول المغذي مع المستوى الثالث من المخصب الاحيائي أعلى مقدار للزيادة في جميع الصفات الخضرية قياساً بمعاملة المقارنة. 2- أدت إضافة المخصب الأحيائي بجميع مستوياته إلى إحداث زيادة معنوية في تركيز النتروجين والفسفور في الأوراق في كلا موسمي النمو قياساً بمعاملة المقارنة. أدى الرش بالمحلول المغذي بالتركيزين الثاني والثالث إلى حصول زيادة معنوية في العناصر الغذائية NP في الأوراق عند كلا موسمي النمو قياساً بمعاملة المقارنة. كما حقق التداخل بين المستوى الثالث من المخصب الاحيائي والتركيز الثاني من المحلول المغذي والمستوى الثاني من المخصب الاحيائي مع التركيز الثالث من المحلول المغذي اختلافا معنوياً في تركيز النتروجين في الأوراق موسمي النمو الأول والثاني على التوالي قياساً بمعاملة المقارنة التي سجلت أقل نسبة في حين سجلت معاملة التداخل بين المستوى الثالث للمخصب والتركيز الثالث من المحلول المغذي أعلى نسبة مئوية في تركيز الفسفور في الأوراق عند كــلا موسمــي النمو قياساً بمعاملــة المقارنة التي حققت أقل نسبة مئوية.

Effect of various phosphorus and calcium concentrations on potato seed tuber production

ABSTRACTAlthough the effects caused in plants by the calcium (Ca)–phosphorus (P) interaction in calcareous soils are well documented, very few studies report on such effects in nutritive solutions or hydroponic cultivation. In a sand and perlite (1:1 volume) hydroponic system, effects of various P (21, 42, and 63 ppm) and Ca (120, 180, and 240 ppm) concentrations on potato tuberization were studied. A factorial experiment based on a completely randomized design with three replications was conducted. For maximum tuber yield and tuber number production, 21 and 42 ppm P was sufficient, respectively. Increase in P and Ca concentrations in nutrient solutions in early growing season resulted in an increase in shoot and root weight, leaf area, and shoot length linearly, but tuber yield and tuber number did not follow this trend. The maximum tuber specific gravity and total solid percent were also observed in 42 ppm P. The highest tuber number and tuber yield were observed in 120 ppm Ca concentration.

Using Growth and Ionic Contents of Wheat Seedlings as Rapid Screening Tool for Salt Tolerance

High germination percentage with vigorous early growth is preferred for harvesting good wheat stand under saline soils. Therefore, an attempt for rapid screening of wheat genotypes for salt tolerance was made in this study. Eleven wheat genotypes including salt tolerant check Kiran-95were subjected to salinity (120 and 160 mMNaCl) along with non-saline control. Results showed a gradual decrease in seed germination and restricted seedling growth in tested wheat genotypes in response to increasing NaCl concentration in nutrient solution. Among the genotypes, NIA-AS-14-6 and NIA-AS-14-7 exhibited more sensitivity towards the salt stress at the germination stage but NIA-AS-14-6 performed quite satisfactorily later on at the seedling stage. Wheat genotypes NIA-AS-14-2, NIA-AS-14-4, NIA-AS-14-5, NIA-AS-14-10, and Kiran-95 showed better performance in term of root-shoot length, plant biomasses (fresh and dry), K+:Na+ ratio with least Na+ content, and high accumulation of K+ at higher levels of NaCl stress. On the basis of overall results, the categorization of genotypes was carried out as sensitive, moderately tolerant, and tolerant. Wheat genotypes NIA-AS-14-2, NIA-AS-14-4, NIA-AS-14-5, NIA-AS-14-10, and Kiran-95 grouped as tolerant, moderately salt tolerant group comprised of NIA-AS-14-1, NIA-AS-14-3, NIA-AS-14-6, and NIA-AS-14-8, whereas, NIA-AS-14-7 and NIA-AS-14-9 were found sensitive to salt stress. Principal component analysis revealed that components I and II contributed 70 and 16.5%, respectively. All growth parameters are associated with each other except RDW. In addition to growth traits, low Na+ and improved K+ content with better K+:Na+ ratio may be used for screening of salt tolerance in wheat as potential physiological criteria.

Development of Automatic Mixing Process for Fertigation System in Rock Melon Cultivation

This work proposed an automatic mixing system of nutrient solution for rock melon fertigation according to the required electrical conductivity (EC) level. Compared to the manual practice, this automatic system will ensure continuous supply of mixed nutrient solution without the need to daily check and mix new nutrient. Thus, this easy to use and low cost automatic system will reduce the burden of the farmers. This system uses an EC sensor to automatically check the concentration level of the mixed nutrient solution. Other than that, the system only consists of electronic pumps for mixing process and an Arduino board as the controller. The controller will monitor the EC level and run the mixing process when the EC level is below the required level. By calibrating the EC sensors, the test shows that the automatic mixing system is able to accurately keep the mixed nutrient solution concentration in a 400 L mixing reservoir at several required levels.

A glimpse into the effect of sulfur supply on metabolite profiling, glutathione and phytochelatins in Panicum maximum cv. Massai exposed to cadmium

Sugar, amino and organic acid, glutathione (GSH) and phytochelatin (PC) content in plant tissues can be altered by S nutrition, and these metabolites have the potential to lower a plant’s susceptibility to cadmium (Cd) toxicity. In the current study, our aim was to analyze the effect of S nutrition on the metabolic profile and the synthesis of GSH and PCs in Panicum maximum cv. Massai (Massai grass) used for Cd phytoextraction, since this forage grass shows fast growth, high biomass production, and adaptation to soil and climatic adversities. We evaluated in a greenhouse combinations of three S (0.1, 1.9 and 3.7 mmol L−1) and two Cd concentrations (0.1 and 0.5 mmol L−1) in nutrient solution, within a single growth period. The tissues of plants exposed to Cd showed distinct responses related to the primary metabolism. Tryptophan, lysine, and histidine were more accumulated in all tissues when Massai grass was exposed to Cd and was grown with 1.9 and/or 3.7 mmol L−1 S, which indicates that these amino acids are probably involved in Cd accumulation and detoxification in this plant. Among the sugars and sugar derivatives detected, galactinol appears to be the most active in decrease Cd-induced oxidative stress. Although there was no effect of Cd/S combinations on the expression of the genes encoding GSH1 and PCS2, the levels of GSH and PCs were strongly increased by Cd, mainly in roots and samples comprising both stem and sheath material of Massai grass and independently of different metabolic changes occurring in these tissues. Synthesis of the majority of metabolites evaluated in this study was mostly induced when Cd-exposed Massai grass was supplied with 1.9 mmol L−1 S, but more studies in field conditions are necessary to define the optimal S concentration for the plants grown in soil.

Nutrient solution concentration and collection time in phytomass production, content, yield and chemical composition of essential oil of rosemary

ABSTRACTRosmarinus officinalis L. (rosemary), is a medicinal and aromatic species used in the cosmetics and food processing industries. The present study aimed to evaluate the biomass production, content, yield and chemical composition of the essential oil of rosemary in cultivation out of soil with different concentrations of nutrient solution in both harvests. The cultivation of rosemary was conducted in a protected system off the ground, with concentrations of nutrient solutions of 1, 2, 3, 4 and 5 dS.m−1 for fertigation with collections of leaves 100 and 160 days after planting. Nutrient solution concentration influences phytomass production and the content and yield of essential oil of rosemary, though not its chemical composition. The collection time does not interfere in the content of essential oil; however, does interfere in the chemical composition; the production of phytomass and the yield of oil per plant are higher in collections at 160 days after planting.

Effect of Different Culture Nutrient Solution EC on Carrot Top Growth and Nutritional Contents in a Closed–type Plant Factory System

The production of crops in controlled environments is a growing sector of modern agriculture. The objective of this study was to determine the optimal concentration of culture nutrient solution for the production of carrot leaves in a closed-type plant factory. After sowing, seedlings at the two-true-leaf stage were transplanted to a growing bed system. Hydroponic cultivation was performed using a three-layer NFT system. Culture nutrient solutions were supplied at three electrical conductivity (EC) levels (2.0, 3.0, and 4.0 dS·m-1). Measurements of plant growth characteristics, including fresh weight, dry weight, plant height, and leaf area, were performed 14 and 23 days after planting. Differences in culture nutrient solution concentrations did not affect leaf number and chlorophyll content, and did not cause significant difference in antioxidant capacities and total phenol content of carrot plants. However, contents of total phenol, chlorogenic acid, and kaempferol were highest in plants grown in the EC 2.0 dS·m-1 solution, whereas those grown in the EC 3.0 dS·m-1 solution had the highest fresh and dry weights. Collectively, our results indicate that an EC 3.0 dS·m-1 culture nutrient solution combined with a cultivation period of 20-25 days is optimal for the hydroponic cultivation of carrot leaves in a controlled environment. In addition, we found that carrot leaves contain antioxidant compounds and are thus suitable as a leaf vegetable.

Variation of nitrogen accumulation and yield in response to phosphorus nutrition of soybean (Glycine max L. Merr.)

ABSTRACTPhosphorus (P) is essential macronutrient for soybean [Glycine max (L.) Merr.] growth and function. The objective of this study was to determine effect of phosphorus nutrition (including phosphorus nutrition level and interruption of phosphorus supply) on nitrogen accumulation, nodule nitrogen fixation and yield of soybean plants by 15N labeling with sand culture. The results showed that they all presented a single peak curve with improvement of phosphorus nutrition level, when phosphorus concentration of nutrient solution was about 31 mg/L, they all reached the maximum and effect of phosphorus nutrition level on nodule nitrogen fixation was lower than that on yield formation level. Interruption of phosphorus supply during soybean growth period, nitrogen accumulation and nodule nitrogen fixation were seriously inhibited, and yield was decreased significantly when interruption of phosphorus supply during V3-R1 and R1-R5 period, while interruption of phosphorus supply during R5-R7 period had no significant effect on nitrogen accumulation, nodule nitrogen fixation and yield. So soybean nitrogen metabolism and yield were sensitive to phosphorus nutrition in the V3-R5 period, those were not sensitive to phosphorus nutrition after R5 period.

GROWTH OF SPINACH (AMARANTHUS TRICOLOR L.) UNDER VARIOUS APPLICATIONS OF NUTRIENT CONCENTRATIONS IN HYDROPONIC SYSTEM OF NUTRIENT FILM TECHNIQUE

The research aimed to discover the response of the growth of two spinach species on Nutrient Film Technique (NFT) hydroponic system and the concentration of the appropriate AB Mix solution on each species. The research was conducted in January to February 2016, at Green House, Faculty of Agriculture, Tadulako University by using Split Plot Design method. The main plot was red and green spinach, while the subplot was the concentration of AB Mix nutrient solution, namely 4 ml/L of water, 5 ml/L of water, 6 ml/L of water and 7 ml/L of water. The research findings reveal that AB Mix nutrient solution was generally very good to support the growth of spinach on NFT hydroponic. The green spinach had better response rather than the red one. There was no interaction between species and the concentration of nutrient solution. The good concentration of nutrient solution for green spinach is 6 ml/L. It was showed by the better growth of plant height on all age of plant, the more number of leaves, the canopy and the root (wet and dry) were heavier, while on the red spinach, 5 ml/L of concentration of nutrient solution resulted in the best growth, yet it was not significantly different from other concentration except on the parameter of plant height and the dry weight of plant canopy.

Effect of selenium application on mineral macro- and micronutrients and antioxidant status in strawberries

The application of selenium (Se) as sodium selenite (Na2SeO3) at 0, 2, and 4 mg L-1 concentrations in nutrient solution to strawberry plants was evaluated. Selenium did not modify the dry weights of the roots, stems, leaves, and fruits, or the fresh weights of the stems and fruits. The 4 mg L-1 concentration caused decreases in the fresh weights of the roots and leaves and in the yield. The mineral content of different plant organs changed but was not adversely affected by Se applications, with the 2 mg L-1 treatment having a lower impact on mineral concentration variation, as well as temporary positive effects on the fruits’ antioxidant status. The fruit pH was not adversely affected by application of Se. Se application in nutrient solution proved to be an adequate technique to increase the Se content in all plant organs. Se concentration exhibited a differential distribution, with the highest levels in the roots, followed by the leaves and crowns; the fruits had the lowest levels, reaching an average concentration of 31.2 mg kg-1 of dry weight. By contrast, fruits from the untreated plants obtained an average concentration of only 6.35 mg kg-1, with no decreases in the concentrations of other mineral elements in treated plants.

Arugula crop cultivation in hydroponic system in the Agreste region of Paraiba State – Brazil, using different plant densities and nutrient solution concentrations

Arugula crop cultivation in hydroponic system in the Agreste region of Paraiba State – Brazil, using different plant densities and nutrient solution concentrations

Growth of Pepper under Different Concentration of the Solutions Used in the Hydroponic System

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.

Análisis de crecimiento y rendimiento de uchuva (Physalis peruviana L.) cultivada en hidroponía e invernadero

The cape gooseberry (Physalis peruviana L.) is an exotic fruit with a growing international market. In Mexico, there is little research on its growth and mineral nutrition. Therefore, the objective of this study was to determine the growth dynamics and yield of cape gooseberry cultivation based on three Steiner nutrient solution concentrations (50, 100 and 150 %) under greenhouse conditions. The experiment was established in Cuernavaca, Morelos, Mexico (18o 58’ 51’’ North latitude and 99o 13’ 55’’ West longitude, at 1,866 masl). The accumulated heat units (HU) were determined and the occurrence of the phenological phases was recorded during crop development. Crop growth was assessed through the number of leaves, leaf area and dry matter accumulated per plant. At harvest, the number and weight of fruits (with and without calyx) were recorded. The phenology of cape gooseberry cultivation was favored with the highest concentration of the nutrient solution, requiring 1,370 HU from transplant to ripeness; this represented 15 and 5 days of precocity compared to the other concentrations: 1,527 HU (50 %) and 1,435 HU (100 %), respectively. The highest leaf production, leaf area, dry matter, crop growth rate and fruit weight (with and without calyx) were obtained with the Steiner nutrient solution at 100 and 150 %, so it is suggested to use the 100 % solution.

Aklimatisasi Planlet Pisang Varietas Raja Bulu Kuning Berbasis Sistem Hidroponik Substrat

<p>Banana is one of the favorite tropical fruit. Banana business development begins with the provision of quality seeds. Tissue culture is a seed propagation technology that can produce large amounts of seed and a relatively short time by utilizing limited plant material. The planlets result of tissue culture needs to be acclimatization before planted in the field. Hydroponic substrate-based acclimatization is expected to produce seeds that are free from soil pathogens. Adjustment of the concentration of nutrients is important in order to produce a growth response that significantly affects and does not cause poisoning or plasmolysis. This study aims to determine whether hydroponic substrate types and nutrient concentrations affect the growth of Raja Bulu Kuning Banana plantlets. The experiment was carried out at net house, Faculty of Agriculture, Universitas Sebelas Maret Surakarta in October 2016 - January 2017. The treatment factors were substrate types (bagasse, arenga peat, steamed husk) and concentration of the nutrient solution (equivalent to EC 1.8, EC 2.0, and EC 2.5 mScm-1). The result showed that steamed husk is the best as the hydroponic substrate, while nutrient solution concentration equivalent to EC 1.8 mScm-1 is sufficient for acclimatization of Banana plantlets cv.Raja Bulu Kuning.</p>

Yield and Mineral Content of Hydroponically Grown Mini-Cucumber (Cucumis sativus L.) as Affected by Reduced Nutrient Concentration and Foliar Fertilizer Application

Nutrient application is one of the major inputs required for hydroponic production of cucumbers. Reduced nutrient solution concentration with supplementary foliar fertilizer application may maintain yield and quality of mini-cucumber, while decreasing the production costs. An experiment was conducted to determine the effect of foliar fertilizer in combination with reduced nutrient concentrations on the yield and quality of hydroponically grown mini-cucumber in a plastic tunnel. Mini-cucumber plants were grown in sawdust, fertigated with nutrient solutions containing 100% (control), 75%, 50%, or 25% of the recommended nutrient concentration (NC) and two foliar fertilizer applications (no foliar and foliar application). The highest fresh and dry weight of mini-cucumber plants were obtained with 75% and 100% NC and decreased with 50% to 25% NC application. The number of marketable fruit and marketable yield on mini-cucumbers increased with 75% to 100% NC, followed by 50% NC, as compared with 25% NC. Deformed fruit were significantly lower at 25% NC than at 50%, 75%, and 100% NC. Foliar fertilizer application did not have an effect on mini-cucumber yield, but reduced the yellowing of fruit. Fruit mineral content (P, Fe, and Mn) was significantly improved by 100% NC. Improvement in yield at 75% and 100% NC was as a result of improved plant height, leaf chlorophyll content, plant fresh and dry weight, and the increase in nutrient uptake of N, P, K, and Mn, which was evident in the analysis of cucumber leaves. The reduced NC of 75% can maintain yield and quality of mini-cucumbers, whereas the application of foliar fertilizer had a limited effect.

Standardization of media and nutrient concentration for coleus (Plectranthus barbatus Andr.) under substrate culture

ABSTRACTColeus (Plectranthus barbatus Andr.) is a medicinal herb whose roots contain forskolin. Incidences of soil-borne diseases, wilt complex and nematodes are the major limiting factors for growing this crop under soil media. Hence, an investigation was initiated for the standardization of soilless growth media and nutrient solution concentration in coleus. Coco peat, vermiculite, sand and their combinations were used as potting media with different concentrations of nutrients based on the recommended dose of fertilizers for soil media (1,080 mg plant−1 nitrogen, 960 mg plant−1 phosphorous and 1200 mg plant−1 potassium). Among the different media and nutrients, plants grown under coco peat media with 80% of the recommended dose of fertilizer for soil (864 mg plant−1 nitrogen, 768 mg plant−1 phosphorous and 960 mg plant−1 potassium) recorded significantly higher root yield (17.10 tha−1) and quality parameters (0.98% forskolin). Benefit–cost ratio was also recorded maximum (4.25) in the same treatment.