Soil quality indicators are measurable soil attributes that reveal the soil productivity response or soil-environment functionality that are used to know whether soil quality is improving, remain constant, or declining. These characteristics could be assessed by different indices such as sustainability index approach (SI) based on the threshold levels of soil indicators and cumulative rating approach (CR) based on crop production limitations, which show the sustainability of soil ecosystem in terms of soil degradation. Since Iran is situated in arid and semi-arid climatic conditions, this research was conducted in agriculture fields of southeast of Mashhad, Iran for comparing these two approaches. Sixty three soil samples (0-30 cm) were collected and nine soil properties such as pH, electrical conductivity (EC), soil organic carbon (SOC), soil particle-size distribution, available water holding capacity (AWHC), bulk density (BD), air capacity (AC), relative field capacity (RFC) and sodium adsorption ratio (SAR) were measured. All these measurements were considered as total data set (TDS). Principal component analysis (PCA) was used to select more effective indicators to conform the minimum data set (MDS). There was a strong correlation between SI and CR (R 2 =0.69, p <0.05). Only six soil indicators selected as MDS (pH, SOC, AWC, BD and SAR) were correlated (p<0.01) significantly with SI and CR. These SI and CR results showed more promising effects on soil sustainability. PCA was found a suitable method for selecting the more effective indicators having R 2 = 0.77 (p <0.05) (CR-MDS versus CR-TDS) comparable with R 2 = 0.80 (p <0.05) (CR-MDS versus SI) to use less soil data input in assessing soil quality in arid zone.
Phalaris minor (littleseed canary grass) is a major weed in wheat fields in some parts of Iran. Diclofop-methyl, fenoxaprop-P-ethyl, and clodinafop-propargyl are three acetyl coenzyme A carboxylase (ACCase)-inhibiting herbicides that are commonly used to control this grass in wheat fields.Thirty-four P. minor populations with suspected resistance to ACCase-inhibiting herbicides were sampled from wheat fields in the provinces of Fars and Golestan in Iran.The dose-response assays that were conducted under controlled greenhouse conditions indicated that 14 populations were resistant to fenoxaprop-P-ethyl, seven populations were resistant to both fenoxaprop-P-ethyl and diclofop-methyl, and three populations were resistant to fenoxaprop-P-ethyl, diclofop-methyl, and clodinafop-propargyl. These populations showed different levels of resistance to the applied herbicides, compared to the susceptible population. These results suggest that different mechanisms of resistance could be involved. The enzyme assay revealed that the existence of modified ACCase in the three most-resistant populations (AR, MR4, and SR3) is responsible for the resistance of these populations.
Teftoon, a flat bread made of whole wheat flour, is prepared by hand sheeting of dough, followed by baking. Different emulsifiers, like lecithin, E471 (distilled monoglyceride) and E472 (diacetylated tartaric acid esters of mono-and digelycerid of fatty acids), were added to the flour at various levels ranging between 0.25 and 1.0% w/w, and it was observed that they improved the dough characteristics. Improvement in bread quality parameters, such as force to tear and sensory acceptability, were monitored. Fungal a-amylase was also incorporated into the flour at 5-20 g/100 kg flour basis alone and in combination with the emulsifier. The force required to tear the fresh bread was decreased with emulsifier and enzyme addition; however, E472 addition at 0.75% w/w of whole wheat flour gave the softest bread. The tear force of stored bread significantly increased with storage; however, bread containing E472 showed a less increase in tear force up to a period of 3 days. The sensory acceptability was found to be higher than that of the control bread for emulsifiers, and lower for enzyme at a concentration higher than 10 g/kg flour. PRACTICAL APPLICATIONSFlat bread is normally consumed fresh, but the staling phenomenon starts immediately after baking this kind of bread. Today, large-scale production and increased consumer demands for high-quality bread with long shelf life have created the need for functional food additives such as emulsifiers and 1 Corresponding 187 a-amylase enzyme. Incorporation of emulsifiers and enzyme decreased the hardness of Taftoon bread. Emulsifiers and a-amylase enzyme enhanced the flat bread dough quality. The sensory acceptability also improved with the addition of emulsifiers. Optimizing the amount of emulsifiers and enzyme required for reduction of bread hardness is vital because the quality and price of the final product depend on this parameter. 188A. KOOCHEKI ET AL. 190A. KOOCHEKI ET AL.
-Smellmelon, an annual invasive weed of soybean production fields in the north of Iran, reproduces and spreads predominately through seed production. This makes seed bank survival and successful germination essential steps in the invasive process. To evaluate the potential of Smellmelon to invade water-stressed environments, laboratory studies were conducted to investigate the effect of desiccation and salinity at different temperatures on seed germination and seedling growth of Cucumis melo. Seeds were incubated at 25, 30, 35 and 40
A b s t r a c t. Quantifying soil quality is important for assessing soil management practices effects on spatial and temporal variability of soil quality at the field scale. We studied the possibility of defining a simple and practical fuzzy soil quality index based on biological, chemical and physical indicators for assessing quality variations of soil irrigated with well water and treated urban wastewater during two experimental years. In this study 6 properties considered as minimum data set were selected out of 18 soil properties as total data set using the principal component analysis. Treated urban wastewater use had greater impact on biological and chemical quality. The results showed that the studied minimum data set could be a suitable representative of total data set. Significant correlation between the fuzzy soil quality index and crop yield (R 2 = 0.72) indicated the index had high biological significance for studied area. Fuzzy soil quality index approach (R 2 = 0.99) could be effectively utilized as a tool leading to better understanding soil quality changes. This is a first trial of creation of a universal index of soil quality undertaken.K e y w o r d s: fuzzy membership functions, principal component analysis, soil quality, treated urban wastewater
-Lesser celandine (Ranunculaceae) is a perennial weed with tuberous root. Tubers are the most important means of reproduction and dispersion of this weed. In recent years, it has spread into wheat fields in Western Iran, mainly in the Lorestan province. A series of experiments were conducted to determine cardinal temperatures and to study the effects of pre-chilling, temperature fluctuations, tuber size, freezing and drying on germination of the tubers, as well as the effect of planting depth on sprouting of the tubers. The results obtained showed that the highest percentage of germination occurred when tubers were stored for more than 2 weeks at 4 or 8 o C. The optimum temperature for germination differed in large and small tubers (8 and 14 o C, respectively). Germination was the highest (almost 100%) at temperature fluctuations of 5-10 o C. Germination of the finger-like and small tubers was the highest (95%); however, very small, small, and broken tubers showed the lowest germination percentage. In the freezing experiment, decreasing the temperature and increasing the storage duration decreased the germination of tubers. Increasing the osmotic potential and temperature resulted in decreased tuber germination of Lesser celandine. Lesser celandine could sprout down to 20 cm depth but heat demand for tubers from superficial depth was smaller than for tubers planted at greater depth.Keywords: freezing; germination; osmotic potential; tuberous root.RESUMO -Celidônia, pertencente à família Ranunculaceae, é uma planta invasora perene com raiz tuberosa. Os tubérculos são o meio de reprodução e dispersão mais importante. Nos últimos anos, essa espécie começou a invadir lavouras de trigo no oeste do Irã, principalmente na província de Lorestan. Experimentos foram conduzidos para determinar as temperaturas limítrofes e estudar os efeitos de pré-resfriamento, flutuações de temperatura, tamanhos de tubérculos, congelamento e dessecação sobre a germinação de tubérculos, bem como da profundidade de plantio sobre a brotação de tubérculos. Os resultados mostraram que a maior porcentagem de germinação ocorreu quando os tubérculos foram armazenados por mais de duas semanas a 4 ou 8 o C. A temperatura ótima para germinação foi diferente em tubérculos grandes e pequenos (8 e 14 o C, respectivamente). A germinação foi maior (quase 100%) sob variações de temperatura entre 5 e 10 o C. A germinação dos tubérculos digitiformes e pequenos foi maior (95%), porém tubérculos muito pequenos, pequenos e danificados apresentaram o menor percentual de germinação. No experimento de congelamento, a redução da temperatura e o aumento no tempo de armazenamento diminuíram a germinação dos tubérculos. O aumento do potencial osmótico e da temperatura resultou em diminuição da germinação de tubérculos de celidônia. Essa espécie pode brotar até a 20 cm de profundidade, mas a demanda de calor de tubérculos plantados superficialmente foi menor do que a dos tubérculos plantados em maior profundidade.Palavras-chave: congelamento, germinação, pote...
In this study, the distribution of leaf nitrogen of two corn hybrids during the growing season, in response to the density and N supply were studied. There were two corn hybrids (S.C. 704 and maxima (MV 524)) under three levels of nitrogen: Recommended (300 kg N/ha); RDN plus 25% (375 kg N/ha); RDN plus 50% (450 kg N/ha) and were three levels of population. Recommended (RDN) (7 plants m -2 ); RDN plus 10% (7.7 plants m-2); RDN plus 20% (8.4 plants m -2 ).Regular samplings were made from 40 days after sowing until crop maturity. Every 2 weeks, a 1 m2 sample of the canopy was cut in four successive vertical layers of equal thickness. Leaf area and N concentration (%) in each layer were measured. The vertical N gradient became more marked with ongoing vegetative development. The whole canopy photosynthetic benefit that would accrue from maintaining the N gradient is likely to be accentuated. The rate of decline in leaf N concentration in a layer was not related to either the initial concentration in the leaves within the layer.
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