جستجوی مقالات مرتبط با کلیدواژه « harvesting time » در نشریات گروه « مکانیزاسیون کشاورزی »

Corn harvest losses are imposed by several factors, the most important of which is harvesting-time. Since the harvesting-time is coincident with the rainy season, it is necessary to appropriately estimate the corn harvest time to avoid harvesting losses and losing the next cultivation. Accordingly, in the current research, the effect of harvesting-time on corn losses during the month and the day has been into consideration. An expert fuzzy system was designed to predict the best harvest time as it operates based on the losses amounts which are measured in processing and collection units into the combine, and losses due to the humidity percentage.

In this paper, corn harvest losses in a John Deere Combine, Model 1165, was studied in a different climatic circumstance in Moghan region. Moreover, a split plot experiment in a completely randomized block design was conducted with three replications. The losses data were collected from the processing and collection units of the combine harvester on the November 5th, 8th and 11th, 2017, in three different daily times of 8-10, 11-13 and 14-16 with three replications. The Mamdani fuzzy inference system with singleton fuzzifire and center average defuzzifire‎ was used to develop a fuzzy expert system.  In the designed expert system, the losses percentage in the processing and collection units and ‎the humidity percentage were considered as system inputs and optimal harvesting time was used as the system output. "Low, Very low, high and very ‎high" and "‏Best, Suitable, Unfit, and Worst" were four groups of linguistic variables for input and output parameters, respectively. These variables follow the triangular and trapezoidal membership functions. The number of 64 fuzzy rules were considered and introduced into the fuzzy system by experts, experienced farmers, and combiners. Furthermore, the same field data (measured data) were applied to evaluate the designed system, so that the predicted value was accounted as the system output.

Analysis of variance showed that there was a significant difference between the harvesting dates at the 0.05 probability level and significant difference between the harvesting times of a day at the 0.01 probability level. It can be concluded that the harvest dates and harvest times of a day were very effective in the number of corn losses, but the interaction effects were not significant. The results appeared that the lowest losses were 10.05% on November 8th, 2017, at 14-16 p.m., and the highest losses were 12.88% on November 11th, 2017, at 8-10 a.m.‎ The amount of losses was increased due to the higher air humidity and lower temperature. In the fuzzy simulation model, the suitable harvesting-time can be predicted based on the losses quantities in the processing and collection units and the humidity percentage. The results showed that the predicted values for harvesting-times, by a designed fuzzy system, were completely matched with measured values in this study. The coefficient of determination (R2) was 0.980 between measured and predicted harvesting times. This coefficient demonstrated that the developed fuzzy logic system was suitable for prediction of harvesting time in the studied area.

The experimental observations in the field and data analysis showed that in the corn harvesting in the Moghan region, the humidity level, date, and harvesting-time were the most effective factors in the harvesting losses. In this paper, based on measured data from a small farm and implementation of the expert fuzzy system, the most suitable harvest date was set on November 8th  at 14-16 p.m, at 21-24°C and relative humidity of 44%-53% to have 10.5% losses which has been confirmed by the lowest losses observed in the corn plan (10%). Moreover, the high value of the determination coefficient demonstrates a high correlation between measured and predicted data.

Olive is one of the plants, that has been cultivated for long in Iran. The average extracted oil is about 65 kg per tree. Four to five kg olives give approximately one liter oil. Olive harvesting problem, is one of the obstacles to development cultivation in Golestan province. Concurrency olive harvesting time with a number of field crops, seasonal precipitation and a lack of the workers are some limitations for development of this fields. Investigative study of the alternative methods instead of the traditional can be desirable strategy for cultivation development of this product. But gardeners are not eager to use this equipment due to lack of harvesting machine. With regard to the afore-mentioned items, the objective of this study was to determine the appropriate method, the optimal time and interaction effect of the two afore-mentioned factors on the measured traits in order to damage reduction during harvesting time. This research was conducted with the two factors, i) date of harvesting and ii) harvesting method. In this regard, harvesting operation carried out at the three dates including; i) 19 December, ii) 3 January and iii) 18 January in 2015. At the three afore-mentioned harvesting dates; olives were harvested with the three methods including; i) traditional (hitting with the long wood by worker), ii) manual comb and iii) motorize pneumatic comb shaker. The measured traits during operations before and during the harvesting time were the abscission naturally percentage, at the start and the end of the harvest, amount of harvesting (harvested fruit percentage), the remaining fruits percentage on the tree, damaged fruits percentage and damaged fruit index. The experimental design carried out in this research was a split plot based on the randomized complete block design, with three replications. The main plots attributed to olive harvesting time at three levels. The sub-plots attributed to types of olive harvesting method at three levels. After sampling and data collection, the data were set in the Excel software. The obtained data analyzed by using SAS software. Analysis of variance (ANOVA) and comparison of means extracted from the output of analysis of the data with a probability level of 5%. Interaction effect of harvesting time and harvesting method on maturity index was significant at 1% level (Table 1). The lowest and highest value of maturity index occurred at the time of 19 December and 18 January (2.28 and 4.07), respectively. The effect of harvesting time on naturally abscission percent was significant at the 5% level. The lowest (1.16) and highest (2.21) naturally abscission attributed at the time of 18 December and 18 January, respectively.
The effect of harvesting method on the percentage of the remaining fruits on the tree was significant at the 1% level. The lowest (2.71%) and the highest (5.89 %) value of the remaining fruits occurred in the manually comb and traditional methods, respectively.
The effect of harvesting method on the amount of remaining fruit on the tree per kg of harvesting was significant at the 1% level. The highest (62.86 gr) and the lowest (27.92 gr) value of this trait yielded in the traditional and manually methods, respectively.
Interaction effect of the harvesting time × harvesting method on the damaged fruits was significant at 1% level. The highest and the lowest values of the damaged fruits took place in 19 December and in the traditional and the manual comb methods, respectively.
The effect of harvesting time on abscission leaf percent was significant at the 1% level. The highest value of 13.2% and the lowest value of 4.47% occurred in 18 January and 19 December, respectively.
Interaction effect of harvesting time and harvesting method on the damaged fruits index, was significant at the 1% level in 18 January. The highest (1.002) and the lowest (0.424) yielded in traditional and manually comb methods, respectively. The results showed that in order to percentage of remaining fruits on the tree, remaining amount on the tree per kg, damaged fruit and damaging fruit index, the best method of olive harvesting is the manually comb method. The lowest percentage of leaves abscission naturally occurred on 19 December. The Lowest percentage of leaf abscission was on 18 January. So the best of olive harvesting method (variety Koroneiky) in the study area, the use of manual comb with maturity index 3.58 is suggested.