Growth and Yield Responses of Red Onions to Different Nutrient Availability in Fertigation System

Nutrient availability affected plant growth and yield. This study aimed to examine the effect of interval application and fertigation frequency toward plant growth and yield, and further determined the most proper fertigation interval and frequency that support the highest plant growth and yield. Experiment was arranged in Split plot randomized Completely Block Design. The main plots were interval of nutrient application, i.e., 3 days interval, 6 days interval, 9 days interval. The sub plots were the frequency of nutrient application, i.e., once/day, 2 times/day, 3 times/day. The plot size for each treatment was 2.5 m×1.3 m and plant spacing was 15 cm×20 cm. Space between beds was 1 m. Red onions (Bima variety) were planting in a raised bed covered with silver black polythene mulch. Before planting, 5 ton/ha manure and 1 ton/ha lime were mix with the soil. Fipronil 1.5% was applied with dose 8 kg/ha to control grubs. Nutrient was mixture between liquid organic fertilizer (7.5 mL/L), rabbit urin (5mL/L) and AB Mix (7.5 mL/L A+7.5 mL B). The nutrient was dispensed 150 mL/plant according to treatment using fertigation system operated remotely using Internet of Things. The nutrient was given from 14 DAP (Days After Planting) until 68 DAP. Irrigation water was dispensed 150 mL daily in the same way. The interval of fertigation significantly affected the growth of red onion (plant height, number of leaves and number of yield). Three days interval of nutrient supply resulted in the tallest plant, highest number of plant leaves, and highest number of bulbs. However, the frequency of nutrient supply daily significantly affected the yield of red onion. The application of nutrient three times/day provided the highest yield (economical dry weight). Further research to examine the effect of fertigation of red onion quality is required.

Germination, Growth and Yield Responses of Leaf Amaranth (Amaranthus hybridus) to Rates and Times of Poultry Manure Application

Manures are more environment-friendly and effective in improving soil fertility, hence their recent preference over inorganic fertilizers. Poultry manure is believed to be the most valuable manure produced by livestock. However, the application had always been only before sowing, unlike the inorganic fertilizers that are, generally, applied after sowing/planting of crops. Therefore, the effects of broiler droppings applied at different rates and times were evaluated on seed germination, growth and yield of leaf amaranths, during the raining season of year 2019. Broilers droppings were applied at 0, 30 and 50 tha-1, at 1 and 2 week (-s) before sowing, at sowing and 1 and 2 (week)s after sowing of amaranth seeds. The experiment was factorial and treatments were replicated thrice in a randomized complete block design. Growth parameters measured were: Plant height, number of leaves, stem girth, leaf area, number of germinated seeds , and yield were measured at 7, 8 and 9 weeks after sowing (WAS). The data generated were subjected to ANOVA at α0.05. At 7 WAS, application of 50 tha-1 manure at sowing produced the highest plant height (17 cm), stem girth (7.40 cm), number of harvested stands (18.33) and marketable yield (7.95 tha-1) with significant differences. At 8 WAS, the highest yield (5.83 tha-1 was obtained from plots treated with 30 tha-1 of poultry dung applied at 2 weeks before sowing while more seeds (27) germinated on both plots treated with 50 t/ha of broiler droppings applied at sowing and 1 WAS. The best recorded values for number of germinated seeds (27) and yield (2.83 tha-1) at 9 WAS were obtained from 50 tha-1 of broiler droppings applied at sowing. 50 t/ha of broiler droppings, at sowing compared well with poultry droppings applied at any rate before sowing.

Prediction of Sediment Yield Using the Algoritma Lavenberg-Marquardt

Erosion and sediment that occurs in the basin is very important to be studied scientifically.Forcasting of sediment yield in a basins area is important to used to evaluate the land-use/landcover change, soil erosion hazard, planning, water quality, water resources in river, and to determine the extent of the damage that occurred in the basins. The algoritmh lavenberg-marquardt can be used to forcest the total of sediment yield the basin area. Artificial neural networks using feedforward multilayer percePsron with three learning algorithms namely Levenberg-Marquardt. The number of neurons of the hidden layer is three to sixteen, while in the output layer only one neuron because only one output target. The root mean square error (RMSE), mean absolute error (MAE), coefficient of determination (R2 ), and coefficient of efficiency (CE). The performance value in the training process, R2, and CE (0.98 and 0.98). As well as for the testing process, R2 and CE (0.98 and 0.97). Based on the performance statistics value, LM is very suitable and accurate for to forcesting by modeling the non-linear complex behavior of sediment yield responses to water discharge, intensity of rainfall, and water depth in the river.

Plant Functional Types Differ in Their Long-term Nutrient Response to eCO2 in an Extensive Grassland

Increasing atmospheric CO2 enhances plant biomass production and may thereby change nutrient concentrations in plant tissues. The objective of this study was to identify the effect of elevated atmospheric CO2 concentrations on nutrient concentrations of grassland biomass that have been grown for 16 years (1998–2013). The grassland biomass grown at the extensively managed Giessen FACE experiment, fumigated with ambient and elevated CO2 (aCO2; eCO2; +20%) was harvested twice annually. Concentrations of C, N, P, K, Ca, Mg, Mn, Fe, Cu and Zn were determined separately for grasses, forbs and legumes. Under eCO2, the concentration of N was reduced in grasses, Ca was reduced in grasses and forbs, P was reduced in grasses but increased in legumes, Mg concentration was reduced in grasses, forbs and legumes and K was reduced in grasses but increased in forbs. The nutrient yield (in g nutrient yield of an element per m−2) of most elements indicated negative yield responses at a zero biomass response to eCO2 for grasses. K and Zn nutrient yields responded positively to eCO2 in forbs and Mn and Fe responded positively in forbs and legumes. The results suggest that under eCO2 the nutrient concentrations were not diluted by the CO2 fertilization effect. Rather, altered plant nutrient acquisitions via changed physiological mechanisms prevail for increased C assimilation under eCO2. Furthermore, other factors such as water or nutrient availability affected plant nutrient concentrations under eCO2.

Physiological and Yield Responses of Spring Wheat Cultivars under Realistic and Acute Levels of Ozone

Tropospheric ozone (O3) is widely recognized as the cause of substantial yield and quality reduction in crops. Most of the previous studies focused on the exposure of wheat cultivars to elevated O3 levels. Our main objectives were to: (i) investigate the consistency of wheat cultivars’ physiological responses across two different realistic O3 levels; and (ii) compare these physiological responses with those under short acute O3 exposure. Three commercially available hard spring wheat cultivars bred under semiarid and Eastern Mediterranean conditions were exposed to two different O3 levels during two consecutive seasons (2016–2018)—36 and 71 ppbv 7 h mean O3 mixing ratios in open-top chambers. The results were compared to those following short acute O3 exposure (102.8 ppbv, 7 h mean for 10 days) in a greenhouse. Non-stomatal responses were significantly more pronounced than stomatal responses in all cultivars under different levels of O3. The specific cultivar was observed as the most O3-tolerant under all experiments. The fact that the same cultivar was found remarkably tolerant to the local semiarid ambient conditions according to other studies and to O3 exposure based on the present study supports a link between cultivar resistance to drought conditions and O3.

GROWTH, PHYSIOLOGY AND YIELD RESPONSES OF FOUR ROCK MELON (CUCUMIS MELO VAR. CANTALOUPENSIS) CULTIVARS IN ELEVATED TEMPERATURE

Rock melon is a high value greenhouse crop. Reduction of economical crop yield in high temperature stress due to global warming is an emerging issue with Rock melon. Therefore, this study was conducted for evaluate the growth, physiology and yield of different Rock melon cultivars grown under high temperature stress. Four cultivars of rock melon (Lady-gold, Lady-green, Himalai-99 and Glamour) were evaluated for their physiological behaviors under two temperature (42±3°C and 47 ±3°C) regimes. In four cultivars of rock melon, leaf area, specific leaf area, relative growth rate, chlorophyll content, photosynthesis rate, stomatal conductance, intercellular carbon dioxide concentration, transpiration rate, malondialdehyde content and fruit yield of Rock melon were significantly differ in each temperature regime. Temperature significantly affects the fruit position in main branch. When temperature increases, Rock melon fruits shifts in to upper branches. While Lady-green and Glamour shown similar attributes in extreme temperature, most susceptible cultivar was the Lady-gold and most tolerant cultivar was the Himalai-99.This study identified the issues of extreme temperature related to the economical yield of rock melon cultivars which can be use in future crop modification and breeding.

Physiological and Yield Responses of Some Selected Rapeseed/Mustard Genotypes to Salinity Stress

An experiment on rapeseed/mustard genotypes was conducted during 2019-2020 rabi season in vinyl house of Plant Physiology Division of Bangladesh Agricultural Research Institute (BARI), Gazipur to find out the salt-tolerant genotypes based on the responses of their physiological parameters and yield. Five selected rapeseed/ mustard genotypes (V1= Jun-536, V2 = BJDH-12, V3 = BD-10115, V4 = BARI Sarisha-14, V5 = BD-6950) were tested at three salinity levels (S0= 0, S1= 5 and S2=10 dS m-1). Irrespective of the genotypes, salinity stress showed a negative effect on the measured physiological parameters as well as seed yield. Leaf chlorophyll contents, leaf area, leaf photosynthetic rate and total dry matter (TDM) were reduced due to salinity stress which ultimately affected seed yield irrespective of the genotypes. However, these parameters were less affected by the salinity in V1 and V2 genotypes compared to others. Sodium and potassium ion contents and their ratios (K+/Na+) in leaf tissues were significantly affected by salinity stress. Among the genotypes, V1 and V2 showed higher K+/Na+ ratios in leaf under both the salinity treatments, and that phenomenon indicated their higher tolerance to salinity than the other genotypes. Catalase (CAT), Peroxidase (POD) activity and Malondialdehyde (MDA) content of the genotypes increased due to salinity stress with variability among the genotypes. The higher CAT and POD activity with lower MDA content was found in V1 and V2 genotypes which indicated their better salt tolerance ability compared to others. These genotypes also showed higher seed yield under both the salinity levels (5 and 10 dS m-1) compared to other genotypes. Based on the responses of physiological parameters and seed yield to salinity, the genotypes Jun-536(V1) and BJDH-12(V2) could be considered relatively tolerant to salinity stress. Bangladesh Agron. J. 2021, 24(1): 43-55