EN 
PT_BR 
The harvest of bean Harvesting is one of the stages with the highest risk of losses in production and requires constant monitoring to avoid damage. In manual or mechanized systems, field measurement allows for the identification of problems with adjustment, speed, and harvest point, and the definition of economically acceptable limits for each crop.
The common bean plant has characteristics that make harvesting a particularly sensitive operation. The pods are close to the ground, maturation can occur unevenly, and the grains are susceptible to cracking and breakage. Furthermore, lodging and toppling of the plants, coupled with rainfall during maturation, can increase losses. According to data released by Embrapa, appropriate harvesting technologies and procedures are important to improve the efficiency of the operation.
In practice, the problem is often only identified when the producer finds a large quantity of grain on the ground or notices lower-than-expected productivity in the warehouse. Systematic measurement of losses allows for anticipating this identification and correcting problems during the operation, transforming the crop's productive potential into economic results.
Losses can occur before, during, and immediately after the harvester passes. Classification helps identify the source of the problem and determine which corrective measure should be taken. Pre-harvest losses occur before the harvesting operation and may be related to pod opening, stem breakage caused by wind, rain or lodging, pest damage, and uneven ripening. On the harvester platform, losses include pods that remain below the cutter bar, grains dislodged by mechanical impact, and plants that are not properly collected.
Losses in the internal system are mainly associated with threshing, separation, cleaning, and transport of the grains. Inadequate adjustments can cause cracks, expulsion of grains along with the straw, or loss of product along with impurities. There are also immediate post-harvest losses related to transshipment, internal transport, and unloading. Although generally smaller than losses occurring in the field, they should be considered when the objective is to evaluate the overall efficiency of the operation.
Each grain left in the field represents lost revenue for the producer. Even seemingly low percentages can represent several bags of beans per hectare. In a crop with a potential yield of 2,000 kg per hectare, for example, a loss of 5% corresponds to 100 kg per hectare left in the field.
On farms with tens or hundreds of hectares, the impact increases significantly, mainly because production costs have already been incurred and will not be recouped for the lost portion. Product quality can also be affected. Broken or cracked grains, as well as those that are excessively dry due to a late harvest, may suffer a price reduction or downgrade in quality.
The practical method consists of delimiting small areas within the already harvested strip, collecting the grains and pods left on the ground, and estimating the amount lost per hectare. The first step is to use a template of known area. Square or rectangular models with 0.5 m² to 1.0 m² can be used. The equipment can be constructed from wood, metal, or PVC pipe. Larger areas tend to reduce the variability of the samples, but require more collection time. Therefore, an area between 0.5 m² and 1.0 m² is presented as a practical alternative.
The samples should be representative of the entire plot. It is necessary to avoid borders and edges, distributing the points in different harvest lines. The material recommends taking between five and ten samples per plot, considering the size and heterogeneity of the area.
After positioning the template over the harvested area, all loose grains, fragments of pods with grains, and whole pods remaining on the ground should be collected. Careful collection is necessary to avoid missing any grains hidden under the straw. The material should be stored in an identified container.
Before weighing, the moisture content needs to be standardized or corrected. One alternative is to determine the mass at the measured moisture content and perform a mathematical correction to the standard commercial moisture content, such as 13%. Another possibility is to lightly dry the material in an oven or in a ventilated environment until it reaches a moisture content close to that of the commercial product. With the mass determined, the loss per hectare can be estimated by extrapolating from the sampled area. For example, if 40 grams of grain are collected in a 1 m² sample, the estimate will be 400 kg per hectare.
If the actual harvested productivity is 2,000 kg per hectare, this loss will represent 20% of productivity, a level considered very high and indicating an urgent need for adjustments.
The assessment can also determine how much of the loss occurred naturally and how much was caused by the harvesting operation. To do this, the first measurement should be taken before the combine harvester passes, in representative areas of the field. The grains and pods found on the ground are collected and used to estimate pre-harvest loss.
After the machine passes, the procedure is repeated. The difference between the total loss found after harvesting and the loss that existed before the operation generally represents the portion attributed to harvesting. This procedure helps to differentiate problems related to operational delays from those caused by inadequate adjustment or incorrect operation of the harvester.
There is no universal percentage that determines the acceptable limit. The result depends on the crop's productive potential, climatic conditions, harvesting system, availability and cost of labor, and the state of conservation and technology of the machinery. As a general field reference, total losses close to 3% to 4% of productivity are indicated in the material as a viable target in well-managed harvests.
Significantly higher values indicate room for improvement. Alternatives include machine adjustments, speed reduction, harvesting earlier or more frequently, and changes to the operational structure. This percentage, however, should be treated as a benchmark. The economically acceptable limit needs to consider how much it costs to reduce losses and how much additional revenue will be recovered.
The producer can initially estimate the potential yield of the crop through sampling carried out before harvest. Then, they should measure losses at the very beginning of the operation and calculate the percentage obtained. The result can be compared to a target range close to 3% to 4%.
If the loss is high, it is possible to test a reduction in speed or changes in the settings and perform a new measurement.
The decision should consider the cost of these measures in relation to the revenue recovered from the grains that would no longer be lost. In this way, the limit ceases to be merely a reference percentage and begins to reflect the economic reality of each property.
What increases losses during harvesting?
The harvest point is one of the determining factors. Harvesting too early can occur with green plants, increasing impurities and damage. Conversely, delaying increases the risk of pod splitting and grain drop. Uneven ripening also makes choosing the ideal time difficult. Failures in irrigation or fertility management and cultivars with different cycles can lead to the presence of both green and dry plants simultaneously. The height of the first pods directly influences the efficiency of the harvesting platform.
Beans that are too close to the ground may fall below the cutting height, especially in uneven areas. Excessive speed also increases losses, as the platform may not collect the plants correctly and the threshing and cleaning systems may operate above their proper capacity. Harvester settings should consider bean characteristics and field conditions, including cylinder or rotor speed, threshing clearances, sieve opening, and ventilation.
The team should monitor losses in each plot, especially at the beginning of the harvest and whenever there are changes in operating conditions. Changes in soil moisture, time of day, variety, or plot can alter machine performance and require reassessment. When losses approach or exceed the defined limit, one measure is to reduce the forward speed and review the platform and threshing system settings. It may also be necessary to bring forward the harvest of more uniform areas to reduce the period of exposure to rain and wind.
In fields with very uneven maturation, strategies such as double passes or prioritizing the most mature areas can be considered, instead of waiting for the entire plot to reach the ideal point simultaneously. More specific decisions should be made with the support of an agricultural engineer, considering the balance between losses, quality, and operational costs.
Choosing cultivars with an architecture favorable to mechanized harvesting can help reduce losses, especially when the first pods are at a good height. It is also important to keep the area level and adjust the harvester according to the manufacturer's recommendations for bean cultivation. The timing of the operation deserves attention. The start of harvesting should consider conditions of lower surface moisture, avoiding plants wet from heavy dew, which can lead to clogging and mechanical damage.
Operator training is also crucial. They must recognize signs of increased losses, such as a growing presence of grain on the ground, and stop operations when further adjustments are needed. The core strategy is simple: measure, adjust, and measure again. Continuous monitoring allows losses to be kept at technically and economically acceptable levels.
Mechanized harvesting involves risks related to moving machinery, rotating parts, and high noise levels. Therefore, appropriate personal protective equipment must be used, including ear protectors, safety glasses, and safety footwear. Gloves should be used when necessary. The harvester manufacturer's safety instructions must be followed.
Loss measurements should never be taken while the machine is moving within the sampling area. According to data released by Embrapa, mechanized harvesting practices are among the recommended production technologies for beans. Significant changes in settings or management strategies should be planned with technical guidance.
Before and during the operation, the producer should use templates of 0.5 m² to 1.0 m² and take samples at different points in the field, avoiding edges. They should also collect all grains and pods containing grains found in the delimited area, standardize or correct the moisture content before weighing, and calculate the loss per hectare and as a percentage of productivity. Comparing measurements before and after harvest helps to distinguish between natural losses and those caused by the operation.
Whenever the results approach or exceed the established limit, the recommendation is to adjust the speed and settings and repeat the measurement to verify the effect of the correction. Recording the results by plot and by crop allows you to create a history and guide future improvements.
This content is for informational purposes only and does not replace the assessment of an agricultural engineer under real field conditions.
