Post-harvest technologies
S. Sharifi; M. H. Aghkhani; A. Rohani
Abstract
Introduction
On the field and in the paddy milling factory dryer losses have always been challenging issues in the rice industry. Different forms of losses in brown rice may occur depending on the field and factory conditions. To reduce the losses, proper management during pre-harvest, harvesting, and ...
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Introduction
On the field and in the paddy milling factory dryer losses have always been challenging issues in the rice industry. Different forms of losses in brown rice may occur depending on the field and factory conditions. To reduce the losses, proper management during pre-harvest, harvesting, and post-harvest operations is essential. In this study, different on-field drying and tempering methods were investigated to detect different forms of brown rice losses.
Materials and Methods
The present study was conducted on the most common Hashemi paddy variety during the 2019-2020 season in Talesh, Rezvanshahr, and Masal cities in the Guilan province, Iran with 0.2 hectares and 5 paddy milling factory dryers. On the fields, the method and date of tillage, irrigation, and transplanting used in all experimental units were the same. Moreover, the same amount of fertilizer and similar spraying methods were used across all experiments. For the pre-drying process on the fields, the following three pre-drying methods were applied on the harvest day: A1) The paddies were spread on the cut stems for insolating, A2) The paddies were stacked and stored after being placed on the cut stems for 5h, and A3) The paddies were covered with plastic wrap and stored after 5h of insolating. The first method (A1) is the most common in the area and was chosen as the control treatment. For the second step of the process, the time interval between the on-field pre-drying and threshing was considered: B1) 14 to 19h post-harvest; B2) 20 to 24h post-harvest, and B3) 25 to 29h post-harvest. Afterward, methods A1 to A3 were combined with methods B1 to B3 and feed into an axial flow-thresher at 10 kg min-1, 550 rpm PTO, and two levels of moisture content at 19 and 26 percent (% w.b). The third process was two-stage or three-stage tempering for 10 or 15 hours resulting in four levels (C1 to C4) and was done in the conventional batch type dryer under temperatures of 40 and 50 ˚C and airspeeds of 0.5 and 0.8 m s-1 in paddy milling factories. At the end of each process, a 100g sample was oven-dried for 48h and a microscope achromatic objective 40x was used to detect incomplete horizontal or vertical cracks, tortoise pattern cracks, and immature and chalky grains. The equilibrium moisture content was determined to be 7.3 percent. Losses properties were analyzed using a completely randomized factorial design with a randomized block followed by Tukey's HSD test at the 5% probability and comparisons among the three replications were made.
Results and Discussion
Results demonstrated that the stack and plastic drying methods significantly increased the percentage of losses. In the plastic drying method, the percentage of chalky grains and tortoise pattern cracks was higher than other forms of loss. In the first process, irrespective of the pre-drying method, the losses were reduced at a lower level of moisture content. At the end of the first stage, losses in the spreading method were significantly lower at 19% moisture content. Threshing the plastic-wrapped paddies after 14 to 19 hours at 19% moisture content resulted in the maximum threshing loss of 8.446% and over half of the grains were chalky or had tortoise pattern cracks. The threshing loss was halved (4.443%) for paddies threshed 25 to 29h after spreading at a moisture content of 26%. The mean of losses in the second step of the process were 7.229, 5.585, and 5.156% for the time interval between the on-field pre-drying and threshing of 14 to 19h, 20 to 24h, and 25 to 29h, respectively. In the last step of the process in paddy milling factory dryers, there was no significant difference in the minimum percent of losses between 10 and 15 hours of three-stage tempering at 40 °C and with 0.5 m s-1 airspeed. Furthermore, maximum total losses with the most incomplete horizontal and vertical cracks occurred in the two-stage 10h tempering at 50 °C and with 0.5 and 0.8 m s-1 airspeed.
Conclusion
Food security has always been a critical matter in developing countries. Furthermore, identifying the source of losses in the fields and the factories is one way to reduce losses and achieve food security. Stacking or wrapping the paddies in plastic after pre-drying on the fields for 5h is not recommended in terms of its effect on increasing the percentage of brown rice losses. Additionally, due to the importance of factory dryer scheduling in the management of the losses, it is recommended to use a three-stage 10h tempering at 40 °C and with 0.5 m s-1 airspeed.
Agricultural waste management
M. Safari; M. A. Rostami
Abstract
IntroductionIn conventional combine harvesters, wheat chaff is typically removed from the end of the machine and deposited on the field surface. Depending on the wheat cultivar, cultivation method, and growing conditions, the amount of chaff produced can range from 0.8 to 1.5 times the amount of grain ...
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IntroductionIn conventional combine harvesters, wheat chaff is typically removed from the end of the machine and deposited on the field surface. Depending on the wheat cultivar, cultivation method, and growing conditions, the amount of chaff produced can range from 0.8 to 1.5 times the amount of grain harvested per hectare (Tavakoli, 2012). On average, this translates to an annual production of approximately 14 million tons of chaff, which is valued at around $240000000 based on regional prices in 2018-2019 ($1000 per kilogram). If collected, these chaff residues could be used as animal feed for livestock. Additionally, the long stems protruding from the back of conventional combine harvesters can interfere with subsequent cultivation efforts. Chaff combine harvesters have a similar structure to conventional machines, but feature a modified end that includes a tank and blower for collecting and depositing crushed chaff. Apart from the threshing unit, all other components of the harvester remain unchanged.Materials and MethodsThis study was conducted in 2019 in dryland wheat fields to determine the performance of Chaff combine harvesters in Kurdistan province. The study used 15 combine harvesters, including John Deere models equipped with chaff threshers from Shiraz, Bookan, and Hamedan, as well as the Hamedan Barzegar specific chaff collector combine. These combines were evaluated and compared based on natural losses, head and chaff storage losses, field capacity, purity percentage, and yield in field conditions in Kurdistan province. The total number of combines evaluated was 15, using a completely randomized design. Among these, 33% belonged to Shiraz company (5 samples), 33% to Bookan (5 samples), 20% to Hamedan (3 samples), and 14% to Hamedan Barzegar (2 samples). Sampling included measurement of natural losses, header losses, threshing tank losses (losses of the threshing unit, separating unit, and cleaning unit), and quality losses (broken grains and impurities) in the combine tank.Results and DiscussionThe results showed that the average yield, natural loss, and combine loss were 1,698.14 kg.ha-1, 2.39%, and 4.92%, respectively. In terms of the loss rates in different parts of the combine, 43.49% was related to the chaff storage of the combine, and 56.50% was related to the combine head.The natural loss rate in this province was 2.39%. The total combine loss was 5.18%, with 40.44% of that related to chaff storage and the rest related to the combine head. The results also showed a significant difference between the treatments in terms of field capacity, chaff storage loss, and purity percentage at a probability level of 5%.The total loss of the Hamedan Barzegar combine was 6.67%, which was higher than the other combines. The chaff storage loss of the Shiraz, Bookan, Hamedan, and Hamedan Barzegar combines were 0.87%, 2.64%, 0.78%, and 4.28%, respectively, showing a significant difference at a 5% level. There was also a significant difference between the treatments in terms of total grain loss.Based on these results, it is recommended to use the Hamedan, Bookan, Shiraz, and Hamedan Barzegar combines, with total losses of 4.33%, 4.33%, 4.52%, and 6.56%, respectively.ConclusionThe average purity of harvested grains was 96.62%, and there was no significant difference between the combine harvesters in this regard.There was a significant difference between the combines in terms of field capacity at a probability level of 5%. The field capacity of the Bookan, Hamedan Barzegar, Hamedan, and Shiraz combine harvesters were 0.83, 0.87, 0.83, and 0.73 hectares per hour, respectively.In Kurdistan province, the average grain combine loss in dryland wheat harvesting with chaff combine harvesters was 4.92%, which is higher than in other provinces.The loss in the chaff tank of the Shiraz, Bookan, Hamedan, and Hamedan Barzegar combine harvesters was 0.87%, 2.64%, 0.78%, and 4.28%, respectively. Regardless of head losses, the loss in the Hamedan combine was less than other combine harvesters.The total losses of the Hamedan Barzegar, Bookan, Shiraz, and Hamedan combine harvesters were 6.56%, 4.32%, 4.52%, and 4.30%, respectively, with the Hamedan Barzegar and Hamedan combine harvesters having the highest and lowest losses, respectively.Based on the results obtained from this study, using the Hamedan combine is recommended in the dryland conditions of Kurdistan due to its low losses, high purity, and field capacity.AcknowledgementThanks to the Agricultural Jihad Organization of Kurdistan Province, specifically the deputy of the Plant Production and Mechanized Technologies Department, for their assistance and cooperation in the implementation of the project.
M. H. Rahmati; Gh. A. Sohrabvandi; M. Khodadadi; A. M. Razdari
Abstract
Rice is a main food for Iranian people and has an important role in providing food security. Regarding the population growth, increase of rice production and reduction of losses have special importance in prevention of rice import. Rice losses in the harvest stage are the highest through the whole production ...
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Rice is a main food for Iranian people and has an important role in providing food security. Regarding the population growth, increase of rice production and reduction of losses have special importance in prevention of rice import. Rice losses in the harvest stage are the highest through the whole production period of this crop and hence the reduction of these losses is necessary. Provision of this purpose depends on on-time harvesting and separation of grains from chaff with the least grain losses, and choosing a suitable harvesting method. The choice of harvesting method depends on various factors in each region; thus, different harvest methods in each region must be compared while conducted in the same conditions. In order to recommend the beast harvest method in Shivan-Chardavol region, three harvesting methods (manually, rice-specific combine harvester and conventional cereals combine harvester) were considered as three experimental treatments and four different parts of this region considered as experimental blocks. The experimental design was randomized complete block design. This study was carried out on Anbarboo variety and the measured factors were: effective farm capacity, percent of total losses, percent of harvesting losses, number of workers and harvesting cost. The results of this study indicated that the total difference of factors was significant at the 1% error level among all treatments. The effective farm capacity in harvesting by cereals combine harvester was more than other treatments. The lowest percent of loss was observed for harvesting by rice-specific combine harvester (2.32%) and the highest percent of loss was obtained for cereals combine harvester (3.816%). The manual harvesting method had the highest harvesting cost and the lowest cost was found to be associated with the rice specific combine harvester. Therefore, from the results of this study, the use of this combine harvester is recommended for rice harvesting in this region.
