کوروش رضاپور

The annually production of cattle manure is estimated around six million tons in Iran. Manure transportation with high moisture and low density recognized as crucial issue. The densification of dry or wet manure is the profound method for decreasing the manure volume which reduces the cost of handling and storage. Besides, the particle size is one of the important factors in the pellet production. Ball mills, vibratory mills, hammer mills, knife mills, two roll mills, colloid mills, attrition mills, or extruders can be used for size reduction of biomass. Specific energy consumption for size reduction of biomass highly depends on moisture content, bulk and particle densities, feed rate of the material, particle size distribution (initial/final particle size) and machine variables. The present study is conducted for wet cattle manure size reduction machine. Furthermore, the relationship between moisture content (35, 40 and 45 %w.b) and drum of special size reduction machine in rotational speed (150, 200 and 250 rpm) considering geometric mean diameter of particle and size distribution of wet cattle manure were investigated. A factorial experiment under randomized complete design method was employed with three replications.

The main parts of machine include drum, concave, spring and adjusting screw. The main function of this thresher machine is to combine crushing and cutting in order to conduct the size reduction methods, i.e., to apply compressive and shear forces to the cattle manure particles. The drum is also equipped with several rows of sharp-edged milling segments. The spring constants were determined by evaluating the slope of the force vs. deflection curves. The rotational speed of drum was changed in the range of 100-700 rpm during these experiments. In the test of the machine physical properties of grinds such as geometric mean diameter of grind particles and particle size distribution were determined. One kg of cattle manure was grinded in each test and the particle size distribution of grinded cattle manure was determined according to ASAE standard S319.3. The moisture content of cattle manure was obtained according to ASAE standard S358.3.

The initial and final particle size of the materials are 20 millimeters and less than 5 millimeters, respectively and the angle of nip is 30 degrees (according to the installation space limitations), the diameter of the drum is 310 millimeters. The spring constant was equal to 24.371 N / mm and on the basis of the experiments a drum speed in the range of 150–250 rpm is considered to be optimal settings for the milling for cattle manure disintegration. The results of Table 4 show that for wet cattle manure with 35% (w.b) moisture content at 250 rpm rotational speed of drum (P > 0.05; Skewness = -0.056; Kurtosis = -2.15), 40% (w.b) moisture content at 250 rpm rotational speed of drum (P > 0.05; Skewness = 0.076; Kurtosis = -1.77), 45% (w.b) moisture content at 200 rpm rotational speed of drum (P > 0.05; Skewness = 0.095; Kurtosis = -1.72), in grinds that would potentially produce better compacts. The geometric mean particle size and standard deviation for each test are shown in Table 2. According to Table (2), the lowest geometric mean of particle size is related to rotational speed of 200 rpm and a moisture content of 45% (w.b), and the highest at rotational speed of 250 rpm and a moisture content of 45% (w.b) can be observed.

The use of cattle manure of thresher machine reduces the specific energy consumption of cattle manure by 92% compared to the conventional method (using drying and hammer mill) in the pellet production.The lowest geometric mean diameter of wet cattle manure was 1.02 millimeter for drum rotational speed of 200 rpm at 45% (w.b) moisture content and the highest was 1.38 at rotational speed of 250 rpm and a moisture content of 45% (w.b%).The best particle size distribution was observed for milling of wet cattle manure with 35% (w.b) moisture content at 250 rpm rotational speed of drum (P> 0.05; Skewness = -0.056; Kurtosis = -2.15), 40% (w.b) moisture content at 250 rpm rotational speed of drum (P> 0.05; Skewness = 0.076; Kurtosis = -1.77), 45% (w.b) moisture content at 200 rpm rotational speed of drum (P> 0.05; Skewness = 0.095; Kurtosis = -1.72)

Tan spot (Pyrenophora tritici-repentis) is one of the most destructive leaf diseases that causes significant damages to wheat during epidemic periods. The application of fungicides is a rapid control practice of the disease during epidemic periods. Under the Integrated Management of Diseases (IDM), fungicides application for controlling leaf diseases is recommended based on disease level (disease pressure), plant growth stages, and only for susceptible cultivars. Several fungicides have been proposed for controlling tan spot, but the efficiency of recommended fungicides is effective when they are used to reduce the disease pressure on important plant leaves especially flag leaf. According to growth stages, four timing have been recommended to fungicides application including, T0 (early stem elongation to node forming 1), T1 (node formation 2-3), T2 (the full flag leaf emergence) and T3 (flowering). The results of fungicides application at different growth stages of wheat are inconsistent and also there is no comprehensive study about the timing of fungicides application for controlling this disease in Iran. Therefore, the present study was carried out to determine the appropriate timing of fungicides application at four wheat growth stages. A field experiment was conducted in a split plot design with four replications. The main and sub-main factors of the experiment were cultivars (Karim and Koohdasht) and the spraying treatments, respectively, and common fungicides (such as Tilte, Folicur, Falcon, and Rexduo) were sprayed at four timings including, T0 (early stem elongation to node forming 1), T1 (node formation 2-3), T2 (the full flag leaf emergence) and T3 (flowering). The spraying treatments were as follows: one, two, three and four spraying times. The efficiency of spraying treatments was evaluated one week after the last spraying by determining the disease index (incidence, severity and area under the disease progress curve; AUDPC) and also comparing the yield and yield components. The results showed that spraying treatments from the full flag leaf emergence to flowering stages (Tr3, Tr5, Tr6, Tr8 and Tr9) decreased the values of AUDPC-I by 42.1 to 80.5% and 33 to 76.6% for Koohdasht and Karim cultivars, respectively, whereas the values of AUDPC-S decreased by 30.7 to 47% and 33 to 58% in Koohdasht and Karim cultivars, respectively. The effect of spraying treatments on damage reduction showed that the damage reduction ranged between 1.4-30.8% and 1.1-29.7% in Koohdasht and Karim cultivars, respectively. The highest damage reduction was observed at the full flag leaf emergence to flowering stages. The highest yield increase was observed at the full flag leaf emergence to flowering stages, which was more than 36% (1071.2 to 1298.9 kg/ ha) and 34% (1054.5 to 1313.8 Kg/ ha) in Koohdasht and Karim cultivars, respectively. The spraying treatments at the node formation stages had the least effect on the yield improvement, which were, respectively, 2.1-7.1% and 1.5-5% in Koohdasht and Karim cultivars. In both cultivars, the comparison of economic profit showed that treatment of Tr3 (flag leaf emergence stage), in addition to decreasing the disease severity and yield increase, and reduction of spraying costs had the highest economic profit compared to other spraying treatments (Tr6, Tr8 and Tr9). Spraying prior to the appearance of flag leaf stage (node formation) was not effective for reducing tan spot severity. The treatment of Tr3 (spraying once at the full flag leaf emergence stage), was the best timing of fungicide application for the disease pressure reduction, and the yield and economic profit increase. In addition to the timing and spraying frequency, the disease pressure reduction rate and yield enhancement, economic profit should be also considered to decide on spraying application.

Spot blotch (Bipolaris sorokiniana)is one of the most destructive leaf diseases that causes significant damages to barley during epidemic periods. Fungicide application is a rapid control practice for this disease during epidemic periods. Several fungicides have been proposed for controlling of spot blotch, but these fungicides are effective if they reduce the disease pressure on important plant leaves, especially flag leaf. The results of fungicides application at different growth stages of barley are inconsistent, and also there is no comprehensive study on the timing of fungicides application for controlling of this disease in Iran. Therefore, the present study was designed to determine the appropriate timing of fungicides application at four growth stages of barley to decrease the disease pressure on the upper leaves of the plant, the timing of spraying on reduction of disease damage, and to increase yield and economic profit. A field experiment was conducted in a split plot design with four replications. The main and sub-main factors of the experiment were cultivars (Sahra and Yousef) and the spraying treatments, respectively, and the common fungicides (such as Tilte, Folicur, Falcon, and Rexduo) were sprayed at four timings including, T0 (early stem elongation to node forming 1), T1 (node formation 2-3), T2 (the full flag leaf emergence) and T3 (flowering). The spraying treatments were selected as once, twice, three and four times spraying that were Tr1 (once spraying at early stem elongation to node forming 1), Tr2 (once spraying at node formation 2-3), Tr3 (once spraying at full flag leaf emergence), Tr4 (once spraying at flowering), Tr5 (twice spraying at node formation 2-3 + full flag leaf emergence), Tr6 (twice spraying at full flag leaf emergence+ flowering), Tr7 (twice spraying at early stem elongation to node forming 1+ node formation 2-3), Tr8 (three times spraying at node formation 2-3+ full flag leaf emergence+ flowering), Tr9 (four times spraying at early stem elongation to node forming 1+ node formation 2-3+ full flag leaf emergence+ flowering) and Tr10 (check). The efficiency of spraying treatments was evaluated one week after the last spraying by determining the index of disease (e.g., incidence and severity, area under the disease progress curve, AUDPC) as well as comparing the yield and yield components. The results of this study showed that treatments with more than once spraying from the node formation 2-3 to flowering stages (Tr5, Tr6, Tr8 and Tr9 treatments) could decrease the values of AUDPC-I between 76.8-86.1% and 68.3-81.2% in Sahra and Yousef cultivars, respectively. Whereas the values of AUDPC-S decreased between 62-65.7% and 60.1-62.7% in Sahra and Yousef cultivars, respectively. The highest percentage of yield increase was observed in the treatments with more than once spraying from the node formation 2-3 to flowering stages, which was more than 37% (1092.8 to 1284.1 kg/ ha) and 41% (1167.8 to 1290 Kg/ ha) in Sahra and Yousef cultivars, respectively. In both cultivars, the comparison of economic profit showed that Tr5 treatment (node formation 2-3 to flag leaf emergence stage) not only decreased the disease severity, but also increased the yield. It also reduced costs and had the highest economic profit compared to other spraying treatments (Tr6, Tr8 and Tr9). According to obtained results, the treatment of Tr5 (twice spraying at T1+T2 timing) was the best timing of fungicide application for the reduction of the disease pressure and the increase of yield and economic profit.

The main objective of this study was to determine an optimal cropping pattern in a productive unit located in Pishva County based on regional and national comparative advantage analysis. In order to achieve this goal, the physical indices of the comparative advantage of production including scale advantage, efficiency advantage, and aggregative advantage with the export advantage of both agronomic and greenhouse crops were calculated. The research was an empirical study based on field survey. Data were gathered through a questionnaire, interview with experts from Varamin Agricultural unit and statistical reports from the Ministry of Jihad-Iran Agriculture and FAO. The results of the study showed that the current cropping pattern of Varamin production unit has scale, efficiency and aggregative advantage and therefore the current farming pattern should be continued. These crops also had efficiency advantage in regional level according to Pishva County cropping pattern Analysis. The analysis of the comparative advantage of greenhouse products at the regional level showed that cucumber, colored pepper and tomatoes had comparative advantage in the province of Tehran. The revealed comparative advantage also showed that cucumbers, colored peppers and greenhouse tomatoes, along with cabbage (leaves, flowers and broccoli), have an export advantage at the national level. Therefore, the optimal cropping pattern of the agricultural unit can be reached through continuing the current cropping pattern along with the addition of greenhouse products with regional advantage and cabbage crop with national and export advantage.

Converting the organic wastes and losses into compost is an appropriate technique to stabilize organic materials. One of the limitative factors in transporting and storing the composts is their low specific mass which usually leads to increase costs in their processing. To overcome this limitation, several methods such as pelleting have been proposed especially for efficient processing of powdery materials. In this study, the effects of pellet particle size (in two levels: 1 and 2 mm), pellet’s moisture content (in three levels: 25, 35, and 45%, wet basis), and kneading length (in three levels: 1, 2, and 3 m) have been investigated on some mechanical properties of obtained pellets including fracture energy, fracture force, and toughness. Obtained pellets were produced using a kneading extruder machine. Experimental results showed that the effect of length of kneading on all studied mechanical properties was significant (p