There is increasing interest in reducing fertilizer cost and establishing proper irrigation management for sustainable vegetable production. Nigari, an effluent of salt industries, is cheaper than commercial fertilizers. Another important vegetable production factor is nutrient application timing to improve soilless cultivation in crops like sweet pepper. Therefore, this study evaluated the effects of nigari and nutrient solution application timing on leaf gas exchanges of sweet pepper cultivated under a soilless system. Treatments included three nigari rates [no nigari plus a standard nutrient solution as control, 2 mL·L−1 nigari + additional nitrogen–phosphorus–potassium (N–P–K) to equal the standard, and 4 mL·L−1 nigari + additional N–P–K to equal the standard]. Three daily application timings (T1 = 0700 hr + 1500 hr, T2 = 0900 hr + 1500 hr, and T3 = 0700 hr + 0900 hr + 1500 hr) were used for each nutrient solution. Leaf gas exchange parameters were studied during the vegetative and reproductive growth stages of sweet pepper cv. Papri new-E-red. Photosynthetic responses and its related parameters, namely transpiration (E), stomatal conductance (g S), and maximum photosynthesis (Amax), were significantly affected by nigari rates and nutrient solution application timing. Photosynthesis-related parameters, E, g S, Amax, and initial slope of photosynthesis in response to light curve were the highest and light compensation point (LCP) and leaf vapor pressure deficit (LVPD) were the lowest at 2 mL·L−1 nigari compared with the control at both plant vegetative and reproductive growth stages. For nutrient solution application timing, the highest E, g S, and Amax were observed at T3 treatment at both plant growth stages. Furthermore, marketable yield of sweet pepper was the highest when 2 mL·L−1 nigari was applied at 0700, 0900, and 1500 hr a day. Leaf gas exchange parameters showed that nutrient solution application timing of 0700, 0900, and 1500 hr a day was better for obtaining high yield of sweet pepper under nigari treatment in soilless culture.
Md. Jahedur Rahman, Haruhisa Inden and Masaaki Kirimura
Md. Jahedur Rahman, Md. Quamruzzaman, Jasim Uddain, Md. Dulal Sarkar, Md. Zahidul Islam, Most. Zannat Zakia and Sreeramanan Subramaniam
Crop-specific nutrient solution and suitable growing media mixtures are necessary in hydroponic system to improve the yield of vegetables. Therefore, an experiment was conducted to specify the required amount of nutrient solution and ecofriendly mixtures of growing substrates of a hydroponic bitter gourd. Treatments consisted two factors, viz., four different types of growing substrate (M 1 = 60% rice husk + 30% coconut coir + 10% vermicompost, M 2 = 60% coconut coir + 30% khoa + 10% vermicompost, M 3 = 60% sawdust + 30% khoa + 10% vermicompost, and M 4 = 60% ash + 30% khoa + 10% vermicompost) and three different composition of nutrient solutions [N 1 = full strength Rahman and Inden (2012), N 2 = full strength Hoagland and Arnon (1940), and N 3 = ½ strength Rahman and Inden (2012)]. Photosynthetic responses and its related parameters, namely, stomatal conductance (g s), transpiration (E), and photosynthetic rate (P N) were significantly affected by nutrient solution composition and growing substrate mixtures. Results revealed that the leaf gas exchange parameters, yield contributing characters, and biochemical parameters showed that full strength of Rahman and Inden (2012) nutrient solution application was better in a growing mixture of 60% rice husk + 30% coconut coir + 10% vermicompost in soilless culture for obtaining high yield and high quality of bitter gourd.
Jasim Uddain, Sanzida Islam Tripti, Mohammad Shah Jahan, Nasrin Sultana, Md Jahedur Rahman and Sreeramanan Subramaniam
The present research was undertaken with the aim of justifying the effect of morphological, physiological, and nutritional properties in organically produced zucchini squash. The experiment consisted of two factors: three levels of pruning (P0 = no pruning, P1 = primary pruning at 20 days after transplanting (DAT), and P2 = secondary pruning at 30 DAT) and four levels of vermicompost application (V0 = control, V1 = 5 t/ha, V2 = 10 t/ha, and V3 = 15 t/ha). The results demonstrated that morphological parameters, reproductive components, and yield and proximate compositions were significant differences among the treatments. Increased male and female flower production were recorded from primary pruning with 10 t/ha vermicompost treatment plots compared with control treatments. Finally, increased fruit number, individual fruit weight, fruit length, fruit diameter, total yield, carbohydrate, protein, crude fat, fiber, and ash were reported from the same treatment combination (P1V2). Taken together, 10 t/ha vermicompost with primary pruning appear to provide maximum output in terms of yield and nutrient value compared with other treatments.