Ministry of Agriculture issues Technical guidance on loss reduction of Mechanized Wheat harvesting in 2015

This technical guidance is applicable to the use of full-feed combine harvester for wheat harvest. In a certain area, wheat varieties and planting patterns should be standardized and consistent as far as possible, and crop and field conditions are suitable for mechanized harvesting. Agricultural machinists should check and debug the machines and tools in advance, determine the suitable harvest time, carry out the quality standards and operating rules of wheat harvesting, and strive to reduce the throwing loss in the harvest process.

I. Inspection and debugging of machines and tools before operation

The wheat combine harvester should be fully maintained and debugged before operation, so as to achieve the best working condition, so as to reduce the failure rate and improve the operation quality and efficiency.

(1) Inspection and maintenance before the start of the operating season

Before the start of the operating season, a comprehensive inspection and maintenance of the combine harvester should be carried out according to the product instructions to ensure that the machines and tools can work properly during the whole harvest period. The wheat combine harvester after reinstallation, maintenance or repair should conscientiously do a good job in trial operation, first in part and then as a whole, conscientiously check the operation, transmission, operation, and adjustment of walking, steering, harvesting, conveying, threshing, cleaning, unloading, and so on, check for abnormal noise and three leaks, and solve the problems in a timely manner.

(2) preparation for inspection before going out during the operation period

Before operation, check whether the function of each control device is normal; whether the free travel of clutch and brake pedal is appropriate; whether the engine oil and coolant are appropriate; whether the indication of the dashboard is normal; whether the tire pressure is normal; whether the transmission chain and tensioner are loose or damaged, whether the movement is flexible and reliable; whether the bolts and nuts of important parts are loose; whether there is water leakage or oil leakage. Whether the cutting table, frame and other parts are deformed or not. Fully prepare common tools, spare parts, fragile parts and oil for field operation, so that they can be eliminated in time in case of failure.

(3) trial cutting

Before the formal harvest, select representative plots for trial cutting, in order to conduct a comprehensive on-site inspection of the technical status of the machine after debugging, and make necessary adjustments according to the operation and farmers' requirements.

During the trial cutting, take the normal working speed to test the cutting distance of about 20 meters, stop the machine, check the loss, crushing, impurity and other conditions after cutting, and see if there are any abnormal conditions such as missing cutting, grass blocking, grain running and so on. If there is something wrong, adjust the cutter gap, threshing gap, sieve opening and / or fan air volume according to the situation. After adjustment, try cutting again and check the quality of the operation until the requirements are met before normal operation can be carried out.

In the process of trial cutting, we should pay attention to observe and listen to the working condition of the machine, and solve the abnormality in time.

2. Determine the suitable harvest time

Wheat harvesting should be carried out from the end of wax ripening to the mature stage, when the yield is the highest and the quality is the best. The main characteristics of wheat maturity are as follows: the lower leaves are dry and yellow in the middle stage of wax ripening, the stem is elastic, the grain turns yellow, full and moist, and the grain moisture content is 25-30%. At the end of wax ripening, the plant turns yellow, only the leaf sheath stem is slightly green, the stem is still elastic, the grain is yellow and slightly hard, the inclusion is waxy, and the moisture content is 20%-25%. At the full ripening stage, the leaves withered and yellow, the grains hardened, showing the true color of the variety, and the moisture content was less than 20%.

When determining the harvest time, we should also arrange the harvest sequence reasonably according to the weather conditions, variety characteristics and cultivation conditions at that time, so as to take measures according to local conditions and rush to harvest in time to ensure that the particles return to the warehouse. Small area harvest should be in the late stage of wax ripening, and large area harvest should be in the middle stage of wax ripening, so that most of the wheat can be harvested in the suitable harvest period. The wheat fields reserved for seed should be harvested at the mature stage. If the rainy season is approaching, or there is an urgent need to plant the next crop, or the varieties are easy to drop grains, broken stalks, broken ears, sprouting on ears, etc., they should be harvested in advance.

III. Quality requirements for machine harvesting operations

According to the requirements of NY/T 995-2006 "working quality of Grain (Wheat) combine harvester", the total harvest loss rate of full-fed combine harvester was ≤ 2.0%, the grain damage rate ≤ 2.0%, the impurity content ≤ 2.5%, and there was no obvious missed harvest or missed harvest. The height of stubble should be consistent, generally not more than 15cm, and the highest stubble returned to the field should not exceed 25cm. There is no grain and land pollution caused by oil leakage after mechanical operation. In order to improve the sowing and emergence quality of the next crop, the wheat combine harvester is required to be equipped with straw crushing and throwing device to ensure that the straw is evenly distributed on the surface. In addition, we should also pay attention to timely communication with users to understand the quality requirements of users for harvesting operations.

IV. measures to reduce the loss of machine harvesting

In the process of harvesting, the correct operation parameters should be selected, and the machines and tools should be adjusted in time according to the different natural and crop conditions, so as to keep the combine harvester in good working condition, reduce the harvest loss and improve the operation quality.

(1) choose the walking route for homework

The combine harvester can generally adopt three walking methods: clockwise centripetal rotation, counterclockwise centripetal rotation and shuttle harvesting. In the specific operation, the operator should choose flexibly according to the actual situation of the land. Stop harvesting when turning, turn at right angles by reversing or turning in circles, and do not turn while cutting, so as to prevent the loss of missed cutting because of the splitter, walking wheel or track to overwhelm the uncut wheat.

(2) choose the speed of operation

The reasonable working speed is selected according to the feed quantity of the combine harvester, wheat yield, natural height, dry and wet degree and other factors. In general, harvesting is carried out at a normal operating speed. When the wheat is dense, the plant is large, the yield is high, the morning and evening and the crop humidity is high after rain, the operation speed should be reduced appropriately.

(3) adjust the width of the operation

When the load permits, we should control the working speed, work at full or close to full width as far as possible, ensure uniform feeding of crops, prevent excessive feeding, affect threshing quality and increase crushing rate. When the wheat yield is high, the humidity is high, or the stubble height is too low, when the operation is still overloaded at a low speed, the cutting width is appropriately reduced to 80%, so as to ensure the wheat harvest quality.

(4) maintain a suitable stubble height

The height of stubble should be determined according to the height of wheat and the leveling of the land, and 5~15cm is generally suitable. If the stubble is too high, due to the different height of wheat or the fluctuation of the cutting table when the locomotive crosses the ridge of the field, it is easy to cause part of the wheat to be missed. At the same time, the effect of plucking and pushing the wheat is weakened, which is easy to cause the loss of landing. In the case of ensuring normal harvest, the stubble should be as low as possible, but the minimum should not be less than 5 cm, so as not to cut the soil and speed up the wear of the cutter.

(5) adjust the speed and position of the reeling wheel

The rotating speed of the reeling wheel is generally 1.1-1.2 times of the forward speed of the combine harvester, which should not be too high. The high and low position of the plucking wheel should make the plucking board act on the cutting crop 2x3, and its front and rear position should depend on the crop density and lodging degree, and move forward appropriately when the crop plant density is high and lodging, so as to enhance the supporting ability. If the rotation speed of the reeling wheel is too high or the position is too high or on the front side, it is easy to increase the grain shedding at the head of the ear and increase the loss of operation.

(6) adjusting threshing, cleaning and other working parts

The rotation speed of the threshing drum, the threshing gap and the angle of the guide plate are important factors affecting the threshing rate and crushing rate of wheat. On the premise of ensuring that the crushing rate does not exceed the standard, measures such as properly increasing the rotating speed of the threshing drum, reducing the gap between the drum and the concave plate, and correctly adjusting the ratio of inlet to outlet clearance (4 ∶ 1) can be taken to improve the threshing rate and reduce the threshing loss and crushing. The loss of cleaning and the impurity rate are opposed to each other and should be considered as a whole in the adjustment. Under the premise of ensuring that the impurity content does not exceed the standard, the cleaning loss can be reduced by properly reducing the fan air volume, adjusting the opening of the sieve and increasing the position of the tail screen. In the operation, the straw blockage in the scripter chassis should be often checked and cleaned in time. The axial flow drum can appropriately reduce the feeding amount and increase the drum speed to reduce the separation loss.

(7) harvesting lodging crops

The cutting stubble should be reduced properly to reduce the missing cutting, the reeling wheel should be moved forward properly, and the spring teeth should be tilted 15 °~ 30 °, so as to enhance the supporting effect. For the crops with serious lodging, measures such as harvesting in the reverse lodging direction, reducing the working speed or reducing the amount of feeding should be taken.

(8) harvesting overripe crops

When the wheat is over-mature, the stem is easy to break and the wheat grain is easy to fall off, and the increase of broken stem after threshing is easy to cause difficulty in separation. during harvest, the rotating speed of the pulley should be properly lowered to prevent the grain loss caused by hitting the wheat ear with the pulley board, and at the same time, the working speed should be reduced, and the opening of the cleaning screen can be properly adjusted, which can also be harvested in the morning or evening when the stalk is tough.