To find an electrical conductivity (EC) in the nutrient solution used for pakchoi (Brassica campestris L. ssp. Chinensis) cultivation that optimizes the plant’s physiology, growth, and quality, we conducted an experiment with eight EC treatments (from EC0 to EC9.6) in a hydroponic production system (i.e. soilless culture) under greenhouse condition in Shanghai, China. Plants biomass production, leaf photosynthesis, vegetable quality variables, tissue nitrate and nitrite contents, and antioxidant enzyme activities were measured. The results showed that very high (EC9.6) or low EC (EC0-0.6) treatments clearly decreased plants fresh weight (FW) and dry weight (DW), leaf size, leaf water content, leaf net photosynthetic rate (Pn), stomatal conductance (Gs), transpiration rate (Tr), and taste score. Nitrite content, and antioxidant enzyme activities were low in medium EC treatments (EC1.8 and EC2.4), but high in very high or low EC treatments. Leaf relative chlorophyll, ascorbic acid, and nitrate contents increased gradually from low EC to high EC treatments, while crude fiber and soluble sugar contents decreased. Based on growth and quality criteria, the optimal EC treatment would be EC1.8 or EC2.4 for pakchoi in the hydroponic production system. Too high or too low EC would induce nutrient stress, enhance plant antioxidant enzyme activities, and suppress pakchoi growth and quality.

Field trials were conducted on tomato for yield and quality of fruits using different types of organic and inorganic fertilizers at the horticulture farm of Bangladesh Agricultural University (BAU), Mymensingh. Fertilizer treatments were tested on two varieties of tomato ca. Roma VF and BARI 15. The fertilization treatments were T 1 , vermicompost (12 t/ha); T 2 , compost (10 t/ha); T 3 , integrated plant nutrient system (IPNS) or mixed fertilizers (organic 2/3 part and inorganic 1/3 part); T 4 , inorganic fertilizers; and a control (T 5 ). Results showed growth and yield (20.8 t/ha) in tomato were higher in the IPNS treatment. A higher number of fruits per plant (73.7) and plant height (73.5 cm) were obtained from mixed fertilizers (organic 2/3 + inorganic 1/3) or IPNS (integrated plant nutrient system) in Roma VF than other treatments. Fruit yield and diameter were found statistically significant. No significant difference was observed in the quality (total soluble solids) of tomato fruits in both varieties' response to the treatments. The electrical conductivity and pH of the soil were improved by the application of organic manure.

Abstract:The impact of chemical farming and the negative consequences on the environment and human health in Bangladesh are on the rise. Organic farming is gaining attention and increasing globally because it is eco-friendly, safe and has benefits for human health. A field study was conducted at the horticulture farm of Bangladesh Agricultural University (BAU), Mymensingh, to evaluate the growth and yield performance of cabbage cv. Atlas-70 using organic and inorganic fertilizers in various plant spacing arrangements. Two factor experiments were conducted on plant spacings of 60 cm × 40 cm (S 1 ), 60 cm × 50 cm (S 2 ) and 60 cm × 60 cm (S 3 ) and fertilizers vermicompost (T 1 ), biogen (T 2 ), integrated plant nutrient system (IPNS) Organic ( 2 /3) + inorganic ( 1 /3) (T 3 ) and inorganic (T 4 ). IPNS (T 3 ) application increased the marketable yield (54.77 t·ha −1 ) of cabbage. The highest marketable yield (48.75 t·ha −1 ) was obtained with a plant spacing of 60 cm × 40 cm (S 1 ). No significant variation was found in plant spacings S 1 and S 2 . The treatment combination of S 2 T 3 recorded the highest plant height (37.81 cm), plant spread (47.75 cm), cabbage head (21.80 cm), stem length (12.31 cm), thickness of the cabbage head (12.53 cm) and marketable yield (65.0 t·ha −1 ). The results suggest that IPNS (T 3 ) combining organic and inorganic fertilizer applications with a 60 cm × 50 cm spacing (S 2 T 3 ) increases the yield performance of cabbage.

Organic farming is increasingly popular among the farmers of Kathmandu valley. However, the organic growers have been facing issues in production, organic certification, and product marketing. To date, little is known about the challenges faced by the organic growers in Kathmandu valley. This study aimed to explore the status of organic farming, attitudes of farmers towards organic farming, their suggestions for improvement, and strengthening the value chain of organic products. Face-to-face interviews were conducted at Agriculture Knowledge Centre, Lalitpur, Nepal during December 2019 with 37 organic growers directly or indirectly involved in organic farming. The results showed that organic growers face challenges in marketing and institutional recognition. Challenges in product certification and marketing were reported by 45.95% of the total interviewed organic growers while they are following organic practices (transitional organic). Our study suggested that reducing the cost of production through easy access to organic inputs like organic seeds, fertilizers, and biopesticides are highly desired by the growers. Participatory Guarantee System (PGS) or group certification along with collective marketing could be the policy implications to address the issues. Organic farming in Kathmandu valley is limited to a niche market; however, due to increasing consumer demand for safe, fresh, and local food the popularity of organic products is increasing to other regions within the country.

Weeds are a challenge, particularly in organic agriculture, due to restrictions on the application of synthetic herbicides and chemicals. A preliminary cultivar evaluation trial of organic sweetpotato was conducted in 2015 at Tennessee State University certified organic farm. Three mulches: wheat straw, pine needle, and black plastic mulch, along with a control (no mulch), were evaluated for their weed management abilities in a sweetpotato field. Four cultivars of sweetpotato were planted in 0.91 m wide mulch beds with 0.3 m row spacing anddrip irrigated with four replications. Data was collected during the growing season on the dry weight of weeds that emerged in a quadrat and yield components at harvest. Results of two-way ANOVA revealed that mulch treatments affected the weed biomass, weed density, and cull yields. Though the use of mulches had no significant effect on other yield components of sweetpotato in this study; it was beneficial for weed management.

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Stem explants obtained from a mature tree of Ziziphus mauritiana Lamk were grown on modified Murashige and Skoog medium containing 3800 mg 1 -l potassium nitrate, 2475 mg 1 -l ammonium nitrate, 11 ~tM benzyladenine and 0.5 ~tM indole-3-acetic acid. During successive subcultures 15-20 shoots per inoculum were produced. Rooting was induced by pretreatment with 50 ~tM indolebutyric acid or 1-naphthaleneacetic acid for 24 h followed by transfer to auxin-free White's medium. Plantlets grew well in a soil and vermiculite mixture.

Callus cultures of Prosopis tamarugo Phil (Leguminosae, Sub family -Mimosoideae) were established from hypocotyls and cotyledons on MS medium supplemented with NAA (2.0mg1-1) and BAP (0.2 mgl 1). Regeneration through various juvenile explants was obtained on hormone-free and high cytokinin containing Murashige and Skoog's medium. Multiple shoot buds formation was observed from the embryonic axis on MS medium incorporated with BAP (5.0 mg 1-1)). Elongation of shoot buds was observed on subsequent transfer to MS medium with BAP (1.0-2.5mgl i) or without BAP.Explants containing apical meristem showed higher number of shoot formation at an early period. De novo shoot buds formation through callus morphogenesis was observed at the base of differentiated shoots on high cytokinin containing medium. All the manipulations of salt strength of MS, nitrogen, carbon, ascorbic acid and polyamines failed to induce organogenesis in isolated callus. In vitro produced shoots were rooted on MS medium supplemented with IBA or NAA singly or in combination.