Depending on the purpose of the raw material, the requirements are determined in accordance with which it is necessary to collect corn. This is also a determining factor taken into account when calculating the optimal time frame within which to harvest the plant for grain or high-quality silage. Harvested crops must also be properly processed and stored.
Cleaning time
Corn seeds should be collected when they are ripe enough, and their moisture content will be from 30% to 40%. Sometimes the grain is still immature, but there is a risk of thermal damage. In such cases, a moisture level of about 40-45% is also suitable. If this indicator is less than 18%, the losses will be huge. Meanwhile, the exact timing depends on the purpose of the harvest.
For grain
In this case, the main task of the farmer is to get corn with the highest dry weight content. For these purposes, lodging resistant hybrids are often grown. To obtain grain on the cob, their collection should begin with a dry mass of about 60%. If it is planned to harvest with threshing grain, then the optimal value of this indicator can exceed 70%.
Whether the dry matter content has reached the desired level can be determined by the presence of a black layer at the place where the grains are attached to the core. In addition, they must be shiny and solid.
Touching corn during a period of high grain moisture does not make sense, since at this time the proportion of impurities, crushed grains and damaged seeds increases significantly, which negatively affects the marketability of grains.
Please note that usually the cleaning process stretches for 2 weeks. To prevent crop shortages, hybrids with different ripening periods should be sown. If you need to assemble a millstone with a high dry mass content as early as possible, it is worth growing early ripe hybrids.
In any case, corn should not be left in the field until late autumn, because due to frequent rains, it can be affected by fungal diseases, which will lead to a significant reduction in its feed value. In addition, in this case, the probability is high that the seeds will lose their germination.
To silo
Corn is harvested at the stage of wax ripeness of grains or at the end of the milky-wax stage. During this period, it has the following characteristics:
- leaf moisture - about 65-70%, and grains - from 35% to 55%;
- the dry weight content in grain is 60%, in cobs - more than 55%, in the whole plant - 28-35%.
If you harvest at an earlier stage in the development of corn, you can lose a significant part of the nutrients. The fact is that at the beginning of the milky-wax stage, due to the high moisture content of grains and loss of dry weight, the silo becomes more acidic and loses about 5% of dry matter with juice. In addition, premature cleaning is unacceptable, since it leads to a lack of energy by 1.3-1.7% per week.
If silage is harvested at the stage of wax ripeness of corn grains, it will provide animals with energy by 20%, which will reduce feed costs, but not to the detriment of the productivity of dairy cattle. So, high-quality corn silage is especially useful for cows, because it satisfies their energy needs, which contributes to the production of milk in large volumes.
In determining the optimal timing, attention should be paid to the share of ears. The higher it is, the more the acceptable period shifts to the end of the wax ripeness phase. To get a silo with high feed value, it is worth harvesting when the cob share reaches about 50%. If corn silage is carried out in this phase, it is possible to avoid juice infiltration from silage, which can lead to problems during mass compaction, fermentation processes and aerobic stability.
Climatic conditions are another important factor, because corn is quite sensitive to frost. At the stage of wax ripeness, it can withstand up to -4 ° C. Frozen corn for silage will need to be removed within 5 days, because with the onset of plus temperatures, the plant can become infected with fungi and bacteria, rot or break.
Crops that have been frozen or drought need to be urgently removed, because excessive dry mass (more than 30%) in the leafy mass will negatively affect the silage process.
How to harvest for grain?
There are two ways to do this:
- cutting ears (with or without cleaning);
- threshing raw materials (using corn harvesters).
The first method is used to harvest food and seed corn, and the second - fodder.
Regardless of the specific method, the farmer must comply with agrotechnical requirements, and according to the results of all work, conduct quality control.
Agricultural technology
Before proceeding with cleaning, it is worth considering the following requirements:
- When harvesting the cobs, the completeness of their collection should be at least 96.5%. The maximum proportion of broken cobs is 2%, and damaged grains in the cobs are 1%.
- When harvesting without cleaning, the exfoliation of grains in the ears should not be more than 1%, and when harvesting with cleaning, not more than 2%. In the second case, the degree of cleaning the cobs from wrappers should not be less than 95%.
- When harvesting corn with threshing, grain losses behind the combine should not exceed 0.7%, and under-grinding should not exceed 1.2%. The crushing rate should not be more than 2.5%, and the presence of grain in the silage - 0.8%. In general, when threshing, damage to grains should not exceed 2%. The minimum indicator of their cleaning is 97%.
- When harvesting with grinding and collecting leaf-stem mass, the stems must be cut at a height of 10-15 cm. Moreover, the completeness of the collection can not be less than 98%. In addition, it is important to prevent the loss and contamination of the mass during its immersion in the vehicle. The content of particles up to 50 mm in the crushed mass is at least 85%.
If grain harvesters are used, the surface of the grains in the ears cannot be more than 6%, and if the corn is harvested - not more than 1.5%.
Collection machines and traffic pattern
For grain harvesting, the following combines are often used:
- Kherson-200;
- Kherson-7;
- KOP-1;
- KSKU-6;
- combine with the PPK-4 prefix.
In combination with this technique, a header is used, which helps to improve the process and reduce losses. If necessary, it can be replaced with a 4-8-row device for harvesting corn, which allows you to cut the cobs, and throw the straw into the field in a crushed form. It will be automatically chopped with cutting elements integrated under the combine.
To comply with all agrotechnical rules, the direction of movement of the harvester must coincide with the direction of sowing. In this regard, farmers use three main ways of moving the unit:
- tone - the retractable pen is reduced by a right turn;
- gonova - the swath width increases with the help of the left turn;
- combined - at the same time two of the above methods of movement are used.
What each method represents can be seen in the diagram below:
“A” - tone method, “b” - gon, “c” - combined; 1, 2 and 3 - pens; C is the width of the pen.
In more detail, we will figure out the example of the driving method:
- Before harvesting, mow down on all sides and break into swaths, starting from the butt spacing.
- The number of rows in the pen should be a multiple of the width of the seeder, and the width of the swaths between the pens should be equal to the width of the sowing unit. For example, if the sowing is 8-row, you need to mow 4 rows on each side of the butt row spacing.
- The width of the longitudinal slopes should be sufficient for the first pass of the machine (3-6 m), and the slopes of the headlands should be no less than the width of the headland when sowing (25-30 m).
- The allowable aspect ratio of the pen is in the range from 1: 5 to 1: 1. If the headland is longer than 1000 m, cross the corral with a bevel of 6–7 m wide.
In the next video, the farmer tells how he collects corn for grain:
You can visually see the process of harvesting corn cobs and threshing grains in the video below:
Quality control
You can evaluate the quality of the work of the corn harvester by several indicators - grain loss, damage to the ears, the degree of cleaning and cutting height.
To calculate the loss of grain, you need an area of 10 square meters. m to collect ears and free grain, determine the average value of their mass and, knowing the yield, find the percentage of lost grain per 1 ha.
To determine the degree of cleaning of cobs from wrappers and their damage in the form of broken rods, it is necessary to find the ratio of the number of uncleaned cobs and broken rods to the total number of cobs in the sample, presented in percentage.
How to collect on a silo?
As mentioned above, corn is often harvested for silage in the period from milk-wax to the end of wax ripeness, and the humidity of the mass should be from 65% to 70%. For this purpose trailed silage and self-propelled forage harvesters are used. What requirements must be observed when cleaning, and how to use the units correctly, we will find out further.
Agricultural technology
In this case, the following requirements should be taken into account:
- the stalks are mowed at a height of 20 cm, which is necessary for excellent silage quality, although the mass of the crop will be somewhat reduced;
- the length of the parts of the plant does not exceed 6 mm;
- when grinding, each grain should be crushed;
- clogging of green mass is unacceptable;
- the optimum dry matter content is about 30%;
- the number of particles of the desired length - at least 70;
- loss of green mass behind the harvester - not more than 1.5%.
Equipment and cleaning principle
The main machine used is a self-propelled forage harvester equipped with a field chopper. In one working pass, it is able to mow, grind and load the mass on additional transport.
As a rule, the KSK-100 self-propelled forage harvester is used, as well as the KS-1.8 Vikhr, KPKU-75 and KSS-2.6 trailed forage harvesters with the PNP-2.4 device
The cleaning process itself is as follows:
- The cutting apparatus of the row or non-row type mows the plant, and the attachment to the knives crumbles it.
- Feeding and pressing rollers feed crushed corn to chopping drums. In them, the cutting length is from 4 to 20 mm, which depends on the specific device. In order to prevent damage to the chopping drum by metal and non-metal objects, it is recommended that the combine be equipped with metal detectors and non-metal foreign body detectors.
- A regrind device such as flattening rollers (crackers), which is additionally equipped with a forage harvester after the first grinding stage, will finally crush whole grains of corn. Otherwise, they will fall in large quantities into the green mass and poorly digested by animals.
Fine cutting allows you to get a silo with a high degree of grinding, which is well compacted and stored well.
The harvested mass must be taken to the silo. To realize the high throughput capacities of forage harvesters, it is necessary to precisely coordinate them with the capacities for transportation, laying and compaction of the silo. The density of addition of the crushed mass is rather low (50-90 kg of dry mass per cubic meter), therefore, in the chain of machines it is required to have large-sized transport units.
If you ensure uninterrupted and coordinated operation of all technological units, the technology using forage harvesters is most effective for obtaining high-quality silage in large fattening and dairy farms with a predominant share of corn for feed.
Unit movement methods
Immediately before harvesting, it is necessary to prepare the field, taking into account the method of movement of the unit. As a rule, if the site is large and with uneven terrain, it is advisable to apply the driving method, which involves the following actions:
- Break the field into corrals that correspond to 2 or 3-day performance of one or more units.
- From all sides, cut the field to double the width of the harvester.
- Beat and mow headlands up to 20 m wide.
- Make swaths up to 8 m wide between corrals.
- If the length of the field exceeds 1000 m, squander the corrals in the middle in the transverse direction in order to prepare the paths for the movement of vehicles.
If the plot is small and not covered with large ridges, you can use the circular method. In this case, it is required to prepare obliques with a width of 3-4 m, and then mow the corners along a radius of 15-30 m.
A direct combining method is also used in the farm for harvesting corn for silage. In this case, proceed as follows:
- Mow the edges of the field and headlands, and then start harvesting corn with KSK-100 and KSS-2.6 combines. It should be borne in mind that the KSS-2.6 combine is attached to the MTZ-100 tractor.
- The ground mass should be transported to the silo trench with the help of GAZ-SAZ 35 07 vehicles and MTZ-80 tractors with 2 PTS-4 trailers.
- Unload cars at the beginning of the trench. Use a bulldozer to slide the silo into the trench.
- Tamp the silo with tractors of the DT-75 brand, and after filling the trench, cover the mass with straw.
Such cleaning is low cost, but a number of disadvantages should be taken into account:
- with a small number of harvesting silos, harvesting takes a lot of time, which leads to an increase in the laying time of the silo, which can lose nutrients and overheat;
- when sheltering a silo with one straw, the nutritional value of the feed is reduced, and the risks of mold growth and spoilage are also increased.
Regardless of the method of movement, if the harvesters are in poor condition when harvesting, the losses when mowing corn will be great. In addition, a significant part of the silo can be lost during its transportation to the trench due to poor road conditions.
Visually see the process of harvesting corn on a silo forage harvester Polesia KVK-800-36 is proposed in this video:
To determine the quality of corn harvesting for silage, it is necessary to evaluate the cutting height, losses and the degree of grinding of green mass.
Post harvest
Regardless of the purpose of the crop, after harvesting the corn grains need to be cleaned of weed mass and, if necessary, subjected to drying.
Cleaning
There are two types:
- primary - allows you to remove all impurities, leaving only the main raw material;
- secondary - allows you to divide the raw materials by the quality of the fractions.
For cleaning corn kernels, special equipment is used, which can be of several classes, namely:
- air separators, with the help of which light impurities of organic origin are predominantly removed;
- air-sieve separators that select small or very large grains;
- Trier installations, allowing to remove difficult to separate impurities of any length;
- pneumogravitational separators that remove difficult to separate impurities of the same size.
As a rule, air-screen units equipped with suction channels and screens of different sizes are used in the farm, which are selected depending on the machine used, and on the properties of the grain, and on the technologies and conditions for its cultivation.
Drying
In addition to cleaning, post-harvest processing involves drying the grain, as they contain a lot of moisture and all kinds of impurities that can negatively affect the storage of the crop.Drying of raw materials is carried out immediately after harvesting and, depending on the moisture content in corn, can be divided into different categories.
Freshly harvested corn can be stored if its moisture content is about 15%. If this indicator exceeds 17%, then grain drying is necessary.
For drying corn, special dryers are used, which can be core, shaft or bunker. Depending on the technical regime, these devices are:
- Recirculating. Such devices involve drying the grains through constant circulation. In this case, the grains can be of different sizes or humidity levels, so recirculation dryers are more popular.
- Direct-flow. In such devices, you need to dry the raw materials of the same humidity level. For one pass, this indicator is reduced by about 6%. If it is initially high, then there are several such gaps. In any case, raw materials must not be allowed to dry below acceptable standard standards.
As soon as the drying in the special equipment is completed, the grains will have a high temperature, so they need to be cooled before storage. Their recommended temperature should not be higher than the ambient temperature by more than 10 degrees.
How to store the crop?
Harvested crops must be properly stored to prevent spoilage and loss of nutrients. Here are the most popular methods for storing grains, taking into account the purpose:
- Technical or fodder corn grain should be kept in bulk in warehouses, silos or silos of the elevator. The height of the embankment can be determined by the capabilities of the storage room. It should be comfortable for the normal maintenance of raw materials and quality control.
- Feed materials can also be stored in metal silos-towers. In this case, you will need to constantly monitor the temperature of the raw materials. Particular attention will have to be paid to the upper and lower layers of the embankment to prevent condensation from appearing in them. Often this occurs when temperature changes in the towers.
- Corn on the cob should be kept in a dry and well-ventilated area, the humidity in which is very low and does not exceed 15%. The optimum height of the embankment of the ears is up to 1.5 m. Before laying them for storage, they must be carefully sorted, all leaves removed and dried to a moisture content of 13-14%.
- Keep grains in plastic containers, cardboard boxes or cloth bags. In the latter case, it is necessary to ensure that the tissue is not saturated with moisture, otherwise the seeds will lose their ability to germinate. Grain in this form can be kept in an unheated room for up to 24 months. Its humidity should not exceed 13%.
- At home, corn can be stored in the refrigerator. Previously, it needs to be cleaned well, soaked in salted and acidified lemon juice water, and then put in bags and put in the refrigerator, but you will need to use it for 10 days.
- To keep the cobs all winter in the freezer, they need to be dipped alternately for 2-3 minutes in icy and hot boiled water, and then dried and wrapped with cling film.
Harvesting corn involves a number of rules and features, depending on whether it is collected for silage or for grain. The difference lies not only in the harvesting process, but also in the principles for determining the optimal timing of work and the units used.