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Solar Spectral Measurements
Published in Frank Vignola, Joseph Michalsky, Thomas Stoffel, Solar and Infrared Radiation Measurements, 2019
Frank Vignola, Joseph Michalsky, Thomas Stoffel
Plants use PAR to transform water and carbon dioxide into sugars and oxygen through photosynthesis. PAR is measured with sensors that filter light to accept radiation between about 400 and 700 nm. Plants mostly use the light near either end of this wavelength range for photosynthesis and reflect more of the green light, thus giving plants their color. Photosynthesis is a quantum process. In other words, photons cause the reactions that occur in plants; therefore, it would seem logical to define PAR in terms of photons per unit time per unit area. If the spectral distribution of sunlight as a function of wavelength I(λ) is known, for example in watts per square meter-nanometer, and the energy of a photon is given by hc/λ in joules, then the photosynthetic photon flux density (PARPPFD) in units of photons/seconds per square meter (s-m2) can be calculated as () PARPPFD=1hc∫400700λI(λ)dλ
Observations of Optical Properties of Natural Waters (The Laurentian Great Lakes)
Published in Robert P. Bukata, John H. Jerome, Kirill Ya. Kondratyev, Dimitry V. Pozdnyakov, of Inland and Coastal Waters, 2018
Robert P. Bukata, John H. Jerome, Kirill Ya. Kondratyev, Dimitry V. Pozdnyakov
The photosynthetic available radiation, PAR, represents the totality of radiation in the 400-nm to 700-nm wavelength interval that is available for photosynthetic activity. However, since the absorption spectrum of algae is not invariant over the PAR wavelength interval, PAR does not transform directly into the amount of radiation that can be used for photosynthesis. The amount of PAR which is pertinent to the photosynthetic process is termed the Photosynthetic Usable Radiation (PUR) and is defined by: PUR(z)=∫400700a(λ)EQ(z,λ)dλwhere a(λ) = specific absorption for chlorophyll at wavelength λ in m2per mg Chl andEQ(z,λ) = spectral quanta irradiance at depth z and wavelength λ in quanta per m2-sec.
Expert Systems for Self-Adjusting Process Simulation
Published in Robert M. Peart, R. Bruce Curry, Agricultural Systems Modeling and Simulation, 2018
The user is asked to enter sensor data or run the system with default sensor files. If the default option is chosen, the sensor data acquisition routines are bypassed. If the user has sensor readings, the program asks how many sensor stations are in the field and requests values of the previous day’s total solar radiation, maximum and minimum air temperatures, rainfall, and photosynthetically active radiation (PAR). These are necessary inputs to the PNUTGRO crop model. If the user does not have a reading for PAR, the program calculates an approximate value from solar radiation. (PAR is needed in photosynthesis routines and influences specific leaf area. PAR is not used directly for water balance calculations but does influence root growth and root water uptake.)
Seasonal variation in sowing and its effect on ethanol and biomass yield of sweet sorghum
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2021
Gaurav S. Pagire, Sharad R. Gadakh, Manaji S. Shinde, Udaykumar S. Dalvi, Vilas R. Awari, Suraj S. Gadakh
The soil of the site is medium black in texture with a pH of 6.8 to 7.4. The genotypes were sown at 60 × 15 cm spacing with 100:50:50 of N, P2O5, K2O kg/ha as a recommended fertilizer dose. The plant height was recorded using measuring tape from the plant’s base to the panicle’s tip (Roy and Barik, 2016). The leaf area of the plant was calculated by taking maximum length and width at the broadest point of the green leaves and multiplying both by the factor of 0.747 (Stickler, Wearden, and Pauli 1961). The physiological maturity was recorded as the appearance of a dark spot on the seed’s hilum (Rao et al. 2013a). Photosynthetically active radiation (PAR) was measured on a bright sunny day between 10 am and 12 pm by LICOR-6400 portable photosynthesis system (Shinde et al. 2013). The total fresh biomass weight was recorded by giving a sharp cut to the stalk at the ground level and the detached stalk was measured by an electronic weighing scale (Rao et al. 2013a). The juice from the stripped stalk was extracted by using an electrically powered three roller crusher and then filtered through Whatman filter paper to remove dry pulpy fibrous residue and measured by a measuring cylinder (Rao et al. 2013a). The juice’s total sugar content was estimated by the phenol sulfuric method given by Dubois et al.(1956 and the computed ethanol was estimated by the formula given by Smith et al. (2019).
Tertiary treatment of municipal wastewater using isolated algal strains: treatment efficiency and value-added products recovery
Published in Chemistry and Ecology, 2020
Swati Rani, Raja Chowdhury, Wendong Tao, Asha Srinivasan
Algal biomass concentration was measured as total suspended solids (TSS) through gravimetric method [27]. Dissolved oxygen (DO) and pH were measured periodically, using a DO metre (Hach LDO) and a digital pH metre. Light intensity was measured using a PAR (Photosynthetically Active Radiation) sensor and a light metre (LI-193, LI-250A, Li-COR Biosciences, Nebraska, USA). COD and BOD were estimated using the methods described in the Standard Methods [27]. Total organic carbon (TOC) was measured in a TOC analyzer (Analytik Jena, multi N/C 3100). Nitrate (NO3-), phosphate (PO4−3), and ammonia (NH3) were measured in an Ion-chromatograph (850 professional IC, Metrohm). Metrosep A Supp 5 100/4.0 and Metrosep A Supp 5 100/4.0 columns were used as anion and cation columns respectively. TKN was measured using the simplified TNT plus simplified TKN s-TKNTM- TNT 880 kit (0–16 mg/L N) (HACH).
Role of nano-powder of Azadirachta indica leaves to regulate the physiological responses and metal uptake in Triticum aestivum seedlings
Published in Chemistry and Ecology, 2019
Anita Singh, Sheo Mohan Prasad, Shikha Singh
Photosynthetic O2 evolution and consumption rates were estimated in leaves of wheat seedlings by Clark type oxygen electrode (Digital Oxygen System, Model-10, Rank Brothers, UK) in presence of 3 ml of 50 mM HEPES–NaOH buffer (pH 7.6) containing 20 mM NaHCO3 as described by Kurra–Hotta et al. [24]. Fresh leaves (50 mg) of treated and untreated samples were sliced in a petri dish containing 1 ml of 0.5 mM CaSO4and transferred into the temperature controlled air tight reaction vessel of oxygen electrode at 25°C. Thereafter, the O2 consumption (respiration) in darkness and evolution (photosynthesis) under the saturating light intensity of 400 μmol photons m−2 s−1 (PAR; photosynthetically active radiation) were recorded. Along with this, chlorophyll a fluorescence parameters were also determined by using hand held leaf fluorometer in the dark adapted (for 30 min) leaves by using FluorPen FP 100, Photon System Instrument, and Czech Republic. Different fluorescence parameters were determined according to Strasser et al. [25].