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Persian oak (Quercus Brantii Lindl) is the most abundant tree species in Zagros mountain range that is affected by western dust storms and harsh droughts in recent years. The lack of spectral-temporal information about these trees has caused limitations on the usage of remote sensing images to make a synoptic estimation of damages caused by dust storms and drought. The objective of this research is to analyse the spectral-temporal behaviour of Persian oak under the stress of water deficiency and dust storms. The aim is to improve the competitive abilities of experts on modelling the stress of water deficiency and dust storms on trees using remote sensing images. For the purpose of this experimental investigation, a greenhouse laboratory has been built. Analysis of the experiments was carried out using 54 two-year-old oak tree seedlings; Fieldspec-3-ADD; and wind tunnel at the greenhouse of the faculty of agriculture of the Tarbiat Modares University in 2016. Results show that the water stress could be modelled much better using geometrical indices extracted from continuum removed spectrum. Area and the depth were best indices. Water stress has been modelled better that dust stress.

Salinity causes nutrient imbalances in plants, even in quinoa (Chenopodium quinoa Willd.), a halophyte with high nutritional value. Current investigation is a complementary study, carried out in continuation of the previous research on quinoa which illustrated that the Salinity Threshold Value (STV) of quinoa varies during different stages of its growth; it was performed in three cultivation periods, each period containing two irrigation methods (IM): i) Irrigating by ‎constant levels of ‎water salinity (ECi) (i.e. 0.3, 10, 15, 20, 25dSm−1) regardless of STV(P); and ii) Considering STV ‎at each ‎growth stage(T). Present study investigated the effect of abovementioned IMs (P, T) and ECis (i.e. 0.3, 10, 15, 20, 25dSm−1) on accumulation of nitrogen (N), phosphorus (P), and potassium (K) ions in shoots (end of vegetation) and seeds (end of seed-filling) of quinoa. Results indicated that an increase in ECi ‎from 0.3 to 25dSm−1, especially after STV, caused a 56.6% and 12.8% increase of N while a 44.3% and 27.8% decrease of P, respectively in shoot and seed of quinoa. K only showed 30.2% increase in shoot. The change of all three ions was sharper in shoot than seed due to halophytic properties of quinoa which reduces salinity influence on seed embryo. The seed of quinoa is the main source of N and protein while the shoot is rich in P and K. The T ‎method of irrigation was preferred for providing the plant chance to survive in more saline condition. [ABSTRACT FROM AUTHOR]

Quinoa (Chenopodium quinoa Willd.) is a high-nutrient halophyte suitable for ‎cultivating in semi-arid climates and saline soils. The current study investigated the ‎effect of various water salinities (ECi) (i.e., 0.3, 10, 15, 20, and 25 dS m−1) and different ‎irrigation methods (IMs) on accumulation of calcium (Ca), magnesium (Mg), ‎sodium (Na), and chloride (Cl) ions in shoot (stem+leaves) of quinoa at the end of vegetation (onset of flowering) and seed at the end of seed-filling. Therefore, 30 pots (five ECi and two IM in three replications) were prepared with similar conditions. Considering that the salinity threshold value (STV) of quinoa varies during growth and is 8, 20 and 15 dSm−1 at each of ‎establishment, flowering, and seed-filling growth stages, the two IMs consisted of considering STV at each growth stage (T) and permanent irrigation by ‎constant levels of ECi(P). Results indicated that by increasing the ECi from 0.3 to 25 dSm−1 the amount of Na, Cl, and Mg in shoot increased 82.2%, 75.8%, and 8.7%, respectively, while Ca decreased 37.2%. In seeds, Na and Cl increased 43.3% and 50%, respectively, while Mg increased 8% and Ca did not change significantly. An increase in ECi ‎significantly changed ion accumulation content, especially at ECi higher than STV, ‎because it is the onset of damage due to salinity stress and particularly in‏ ‏‎shoot compared to seed due to the halophytic properties of quinoa. The T ‎method of irrigation was preferred due to less accumulation of Na and Cl in ‎shoot and seed, and therefore less damage and loss, especially at higher ‎salinities.‎ [ABSTRACT FROM AUTHOR]

The use of bio-mulches to stabilize dust has gained worldwide attention during the last five decades. We report herein on a study of the application of 20 new types of bio-mulches as stabilizing agents. To understand the effect of new bio-mulches on dust stabilization, several tests have been applied for strength, structural stability and wind erosion. Fourier Transforms Infrared and Scanning Electron Microscopy have been applied on untreated and treated soil samples. Bio-mulch modified mechanisms have been analysed. Wind erosion and aggregate stability test results clearly indicate that certain biomulch specimens were useful in controlling dust in relatively arid and semiarid areas. The Scanning Electron Microscopy images show that when bio-mulches were applied to sandy soil, some voids in the soil were filled, while other parts stayed on the surface of soil aggregates. The molecular structure of polyelectrolyte groups reacted chemically with positive ions of the clay grain and created physicochemical bonds between molecules and soil aggregates with ionic, hydrogen or Vander Waals bonds. Untreated samples had no bonds between molecules and soil aggregate, and the strength and erosion resistance were weak. [ABSTRACT FROM AUTHOR]