JOURNAL OF AGRICULTURAL ENGINEERING RESEARCH
Year:2001 | Volume:2 | Issue:7|Papers Count:8

In order to estimate energy and momentum coefficients, several experiments were conducted in some irrigation and drainage vegetated canals in Moghan plain. These experiments involves measurement of the flow velocity, cross section coordinaters, water depth, and sampling the vegetation density in the canals.The coefficients were estimated using two - relationships based on logarithmic and probability velocity distribution. The estimated values were compared to measured results. The comparision showed that the energy coefficient can be estimated using equations of energy, and/or probability and logarithmic velocity distribution, and the momentum coefficient can be estimated using equation of momentum, and/or logarithmic velocity distribution.The statistical and probability analysis of the measured data showed that the energy and momentum coefficients are three variables log- normal in distribution with mean equating to 1.2768 and 1.1005, respectivity.

Study was carried out in an experimental orchard in Golmacan station in Khorasan province on red delicious apple trees. The aims of these experiments were to determine the effects of concentration and spraying date on quality and control of disorders in apple. The CaCL2 concentrations were 0 (control), 0.5,1 and 1.5 percent. Each concentration was applied for 2, 4 and 6 times with 4 replicates.Leaf sampling was done in Tir and element of, N, P, K, Ca, Mg, Fe, Mn, Zn, Cu, B were measured in the lab. The fruits were harvested in the late summer and the quality tests including: Starch, Total soluble solids (TSS), Titrable acidity (TA), PH, fresh firmness and complete tests of elements were done.All the treatments were transferred to a cold storage and kept for 5 months at O°C degrees centigrade 90 percent relative humidity (RH). Each months the quality tests were done for all treatments. Finally, all the treatments were removed from the cold storage in Esfand and quality sensory evaluation tests were done. The data were analyzed. The results showed that 6 times spraying by concentration of 1 % CaCL2 improved quality characteristics.

Almost one third of the world's population consumes rice as a staple food. This important cereal, thus, needs a careful storage and processing to obtain maximum output and also to keep its quality unimpaired. The moisture content of rough rice varieties is often a major concern in their safe storage and proper handling. Paddy product contains substantial amount of moisture when harvested (%25-%35 db) and this high moisture content has to be reduced to a safe level of %14 db. In order to provide proper moisture conditions at a particular stage of rough rice processing, it is often necessary to extract moisture from the material. An understanding of this drying process requires a knowledge of the equilibrium moisture content of the rough rice for the environment to which it is subjected.The objectives of this study were to find the coefficients in Henderson's and Kachru's equation for predicting the equilibrium moisture content for three major Iranian rough rice varieties, viz., Champa, Rashti Domsiah, and Rashti salari. Experiments were conducted on thin- layer drying of rough rice. The coefficients "C" and "n" in Henderson's equation and a0, a1 a2, a3 in Kachru's equation have been found statistically.The experimental data showed a very good agreement with the predicted values by Henderson's and kachru's models.

The large variation of rainfall from one year to another, it's variable distribution and delayed fall's effective rain, are the weather characteristics of rainfed farming area in Maragheh.In such condition a proper scheduling for one or two single supplementary irrigation could have produced a significant difference in crop production.In order to study the effects of single irrigation (during planting & flowering stages 50 mm in each) on yield of 4 varieties of wheat (sabalan cross, Anza cross, Azar2 and sabalan), an experiment was conducted during 1996-1998 in Maragheh station.The amount of rainfall was 351 and 202 mm respectively. Irrigation system was adjustable sprinkler. All wheat varieties showed positive reaction to single irrigation in planting time, but Azar-2 and sabalan cross wheat varieties showed the most in both years with about 1000kg.ha-1 yield increase to a total of2.5 ton. Ha-1. Since Azar -2 had high yield increase in both single irrigation management in planting and flowering stages, it was recommended as the favorable variety.

With regard to food deficit all over the world specially third world countries, there are necessities for preparing of food products specially proteinaceous food. Single cell protein defined as dried cells of microorganisms such as bacteria, yeast fungi, algae, actinoycetes cultivated in a wide scale for use as animal or human food supplement. The present research was conducted to produce single cell protein from straw by a cellulolytic microorganism.Dry weight of cells was 3.4 g/I, the net amount of proteing and the digestion coefficient of straw was 1.2 g/I and 52.3% respectively.The amounts of ash, fat and moisture were 3%,36% and 18% respectively. Also several tests conducted to determine the optimum incubation time, agitation rate and pH. Results showed that the best incubation time was 72 hours, the optimum agitation rate was 140rpm and the optimum pH for protein production was 6.5-7.5.

Soil compaction has adverse effects on soil physical properties and hence on crop yield. It hinders crop root development, increases soil resistance and bulk density, decreases pore size and volume and finally infiltration of water into soil. In order to study the effects of subsoiling on soil physical properties and wheat yield, an experiment consisting of 5 treatments was conducted. The detail of each treatment was as follows: (1) S1P1, subsoiling to a depth of30-35 Cm plus moldboard ploughing, (2) S2P1 subsoiling to a depth of 40-45 Cm plus moldboard ploughing, (3) S1P0 only subsoiling to a depth of 30-35 Cm, (4) S2P0 subsoiling to a depth of 40-45 Cm, and (5) S0P1 only moldboard ploughing (Control). Before conducting the experiment, bulk density, cone index and intake rate were measured. These measurements were replicated after the first irrigation in each plot. Soil layering, texture, and Organic Carbon were determined in the experimental site. Finally, the wheat yield from each plot was measured. The results showed that subsoiling caused reduction in the bulk density and soil cone index and increased the basic intake rate and wheat yield. The best treatment in this study, in view of decreasing soil compaction was S1P1 which caused decreased the cone index, bulk density 12.8 and 4.1, respectively and increased the wheat yield up to 3.8. The S1P1 treatment caused and increase in basic intake rate up to 2.4 relative to basic intake rate prior to irrigation.

Soil moisture measuring is vital for irrigation management and scheduling. However gravimetric method is very time consuming and destructive. In recent years, TDR (Time domain Reflectometry) techniques have been used for measuring soil moisture in short periods of time. Some TDR instruments have portable sensors, which move up and down in the access tubes installed in the soil. Therefore, it is possible to monitor soil moisture content at various depths and locations. The access tubes available by the company marketing TDR instrument is called TECHNAT and is made of special material. These tubes are expensive which limit the possibility of monitoring soil moisture at various locations with a single instrument. As a result replacing TECHNAT tubes with tubes, which are manufactured locally but not from the same material. TECHNAT tubes along with PVC access tubes were installed in two different farms. TRIME TDR was used to measure soil moisture by PVC and TECHANAT access tubes. At the same time, soil moisture was measured gravimetrically from undisturbed samples. Result of comparison between TDR readings in TECHANA T and PVC access tubes using gravimetric method indicates that both tubes can be employed with almost the same accuracy.