Scientifically Reducing Grain Losses Equaling to Increasing Grain Output

The wheat has experienced breaking the ground, sprouting, shooting up and heading, and flowering and grain-filling, and overcome the difficulties of spring coldness, lodging, plant diseases and insect pests. Finally, a critical moment of the summer harvest is coming. In the context of the implementation of the same responsibility of the Party and government, ensuring food security and treasuring and saving grains has become a social consensus, and a key issue is how to ensure that more than 300 million mu of wheat (1 mu = 0.067 ha.) can be successfully kept in the warehouses of China. This is also an important reason why the wheat harvest work conference of the Ministry of Agriculture and Rural Affairs focuses on the reduction of wheat harvest losses.

Both economic cost and time cost for crop harvesting used to be very high. During the harvest season in the past, all the family members had to participate. Sometimes, some people even had to ask for a leave. Now, it costs only RMB 60 yuan/mu to employ a harvest machine to harvest wheat, and the wheat in 10 mu of land can be harvested in an hour. At present, China's wheat mechanical harvest rate has already reached 97%, and the  scenes of "manually cutting wheat straw" and "sweating in the wheat field" have already become the past. Agricultural machinery has allowed farmers to work with dignity. Moreover, not only the efficiency is high, the loss of mechanical harvesting is also smaller than that of manual harvesting. Taking wheat as an example, the manual harvest has to go through several links, such as cutting, bundling, threshing and transportation. The wheat losses will occur in each link, and the comprehensive loss rate is as high as 10%. On the contrary, the mechanical harvest can finish multiple processes at a time. Under normal circumstances, the loss is seven or eight percentage points lower than that in the manual harvest.

At the same time, the mechanical harvest is also upgrading towards high efficiency and low losses. Generally speaking, the foreign countries only set the bars for the safety performance rather than for the operation performance of the harvesting machinery. Enterprises can determine the operation performance by themselves but the choices will be made by the market. Some agricultural machinery enterprises in developed countries control the total loss rate of wheat harvester below 1.5%, while that shall not exceed 1.2% in China. At present, the harvest loss in some wheat combines can be reduced to about 0.8% under normal working conditions, which is comparable to some foreign machinery brands. Of course, although the performance of grain harvesting machinery in China is good, there is still a long way to go before they can be highly reliable. With the extension of service time, the failure rate is relatively high. If the maintenance is not made in time, the harvest loss rate will increase accordingly. This is a fault which needs to be made up for.

Not only the machineries can determine the harvest loss rate, but also other factors should be considered. In terms of natural factors, strong wind and heavy rainfall lead to crop lodging, dry and hot wind lead to grain falling, and water can be accumulated in the field, and all these factors will cause difficulties in mechanical operation and affect the harvest rate. In terms of fields themselves, as the plots are irregular and of different sizes, machineries have to turn around frequently and cannot fully perform its functions. In terms of regional differences, the integration between agricultural machinery and agronomy will also affect the loss rate. For example, the loss of corn harvest is the smallest when machineries can be aligned with the rows. As China has a vast territory, the corn row spacing varies from place to place. From the operator's point of view, the green hands, who have not been fully trained, can't deal with the special situation in time, or pursue the efficiency too much, may set very large feed amount of the harvester so that the loss rate will be very high. In addition, timing is also very important. Early harvest, insufficient grain filling and incomplete grain filling affect the yield. The harvest is conducted too late, grains drop easily, ears are prone to break and thousand kernel weight is low. The loss can be minimized only when wheat is harvested at the best time.

Although the level of loss control is relatively good in China, there is still room for progress, especially for loss reduction. For example, in 2020, China made every effort to increase more than 3 million mu planting area of winter wheat. The wheat production can be increased by about 2.3 billion jin based on the average yield of 383 kg per mu. But if the loss of summer grain can be lowered by one percentage point, more than 2.5 billion jin of grain loss can be saved, especially under the background that the cultivated land resources are insufficient and sowing area can hardly be increased further, scientific loss reduction is equal to yield increase.

Of course, from a scientific point of view, the loss rate cannot be reduced to zero. However, we have to try our best to make the loss rate reduce to near zero.

Firstly, the harvesting machinery should be improved gradually, such as developing machinery suitable for harvesting crops with different cultivation modes and growth conditions, especially the machinery good at coping with abnormal conditions such as lodging. At the same time, it is necessary to develop an intelligent monitoring system for agricultural machinery operation, and issue an alarm to remind the operator to stop the machinery or adjust the machinery automatically in case of abnormal loss.

Secondly, the quality of machinery should be strictly controlled. The unqualified, undurable and unsuitable agricultural machinery products should be unentitled to policy support. The old agricultural machinery should be eliminated through the subsidy policy, and the high-efficiency and low loss harvesting machinery should be adopted. In addition, the complete sets of grain drying equipment should be included in the subsidy pilot, so as to enhance the drying capacity and promote the harvest at the right time.

Thirdly, skilled craftsmen should be developed. It is important to use the machinery in a correct way. In the face of the same working conditions, experienced agricultural machinery operators have a lot of knowledge. For example, facing the wet wheat, they go to work late and finish work early, so as to avoid the entrainment loss caused by the wet straw. Also, they know so well about influence of the engine speed and the swing speed of the screen box on the working effect. Therefore, it is necessary to strengthen the training for agricultural machinery operators, let the experienced operators teach the green hands, organize the competition for the grain loss reduction of mechanical harvest, and promote the harvest operation according to the standards and the rules.

In fact, there will be grain losses in the whole production and supply chain, including the journey from the field to the table, the grain missing during transport, unscientific grain storage and excessive processing, so we need to reduce the loss in the whole chain of "production, purchase, storage and marketing". More efforts should be made in the whole chain, including building a good post-production service system in the process of purchasing, correctly using scientific grain storage equipment in the process of grain storage, promoting green safety technology in the process of grain storage and transportation, and choosing appropriate processing technology in the process of grain processing. Only in this way can we do a good job in saving grain and reducing losses.

SOURCE：http://www.farmer.com.cn/2021/05/26/99870988.html