Rice planter: how to improve seed distribution

Planting rice Between September and December, attention must be paid to the planter's settings to ensure uniform seed distribution and proper stand formation. According to data released in the technical material presented, incorrect calibration can cause failures, an excess of plants in certain areas, and unevenness, compromising the crop's productive potential.

In irrigated rice, the number of plants and the uniformity of the stand are directly related to crop performance. Seeds need to be distributed properly, at a suitable depth, and with good contact with the soil.

According to data released in the technical material presented, large variations in distribution increase competition between plants, leave spaces for weeds, or may favor lodging in areas with an excess of plants.

The window from September to December also presents variations in soil moisture, temperature, and rainfall. A well-calibrated planter contributes to faster and more uniform emergence even in the face of these changes.

Calibration involves adjusting the seed distribution mechanisms, depth, and spacing so that the amount deposited per area is as close as possible to the planned amount.

In practice, the process involves setting the seeding rate, adjusting the metering mechanism, regulating the tractor speed, and checking the amount actually distributed in a test section. It is also necessary to adjust the deposition depth and the pressure of the compaction wheels.

According to data released in the technical material presented, calibration should be repeated when there is a change in cultivar, a change in seed size, a significant alteration in soil conditions, or a change in operating speed.

The seed box and metering devices are responsible for storing and delivering the seeds to the rows. In systems with seedbed discs, rotors, or other mechanisms, compatibility with seed size and shape is important.

The transmission also directly influences the seeding rate. Chains, gears, and gearboxes relate the rotation of the wheels to the speed of the metering device.

The seeding lines guide the seeds to the furrow, while the depth-limiting wheels and compaction wheels help maintain the seeding at the planned depth and contact with the soil.

According to data released in the technical material presented, loose chains, worn discs, obstructed tubes, and bearings with play can compromise uniformity.

Before adjusting the machine, it is necessary to set the seeding rate. The planning considers the number of viable seeds per square meter or linear meter.

Among the factors evaluated are the technical recommendation for the cultivar, the germination rate of the batch, the vigor of the seeds, the soil preparation conditions, and the planting system. Risks of losses caused by birds, soil pests, or waterlogging after heavy rains should also be considered.

According to data released in the technical material presented, the quantity in kilograms per hectare should be calculated from this information and the updated technical guidelines for irrigated rice.

Before adjustment, a complete mechanical inspection is necessary. Cutting discs and furrowers should be evaluated, as well as chains, gears, bearings, lubrication points, and conduit tubes.

Excessively worn parts need to be replaced. The levels and condition of grease and oil in transmissions, where present, should also be checked.

In machines with seedbed discs, the disc must be compatible with the seed size. Large seeds in small cells can cause failures and crushing.

On the other hand, small seeds in large cells can result in double or triple seeding. In systems with a rotor or other volumetric mechanism, it is recommended to check the manufacturer's manual to determine which configuration is indicated for irrigated rice.

The table provided by the manufacturer should be used to select the initial gear combination or gear ratio setting.

According to data released in the technical material presented, this configuration should only be considered as a starting point. The actual quantity distributed needs to be confirmed by bench or field testing.

With the machine raised and secured, the drive wheels can be moved manually, simulating a specific path. The seeds distributed along one or more rows are collected in labeled containers.

Next, the seeds need to be weighed or counted, the result converted to kilograms per hectare or seeds per meter, and compared to the planned rate. If the result is above or below the target, the setting should be adjusted and the test repeated.

A test in motion is necessary even after the calibration has been stopped. The evaluation should be done at the actual working speed, usually between 4 and 6 km/h, according to the manufacturer's recommendation and ground conditions.

According to data released in the technical material presented, the procedure may involve marking a 50 or 100-meter stretch, filling the box with a known quantity of seeds, and weighing the remaining material after the stretch. The result allows for calculating the quantity used per hectare and verifying the actual seeding rate.

The average seed rate is not sufficient to assess the entire regulation. Some lines may exhibit inadequate flow due to blockages, problems in the tubes, or faulty metering devices.

During the test, it is possible to collect seeds from three to five rows separately and compare their weights.

According to data released in the technical material presented, significant differences between the lines indicate the need for cleaning, component replacement, or inspection of the dispensers.

After adjusting the seed quantity, the planting depth must be regulated. In irrigated rice, it is usually shallow, but it needs to ensure adequate coverage with moist soil. The exact value depends on the soil type, moisture, tillage system, and cultivar.

In clayey and moist soils, shallower depths tend to favor faster emergence. In lighter soils or those prone to surface drying, it may be necessary to deepen the planting slightly, without overdoing it.

The settings should be checked on the entire machine and also in the field, verifying directly where the seeds are being deposited.

The tractor's speed affects the regularity of seed distribution. At very high speeds, vibration can increase, causing variations in seed flow, gaps, and clumping.

According to data released in the technical material presented, it is important to maintain the speed within the recommended range for the machine and prioritize the regularity of the operation.

When the desired ratio requires an extreme combination of gears at high speed, it may be more appropriate to reduce the speed and perform a new calibration.

During spring and early summer, producers may face irregular rainfall, dry periods, high-intensity weather events, variations in soil temperature, and strong winds.

Planting in excessively dry soil can increase the risk of uneven emergence. Conversely, waterlogged or poorly drained soil can promote surface sealing and hinder emergence.

According to data released in the technical material presented, the depth should be adjusted according to the current and projected moisture, while the condition of the plots needs to be monitored to avoid blockages and changes in depth.

Calibration doesn't end when the planter leaves the shed. Between seven and 15 days after sowing, depending on soil temperature and cultivar, it's important to assess the actual plant stand. Plant counts per meter should be taken at different points in the field. The results need to be compared to the planned stand and the variation between the points.

It is also important to look for gaps, empty spaces, and clumps in the lines.

According to data released in the technical material presented, systematic patterns of failures in certain rows or strips may indicate blockages, problems with the metering devices, or irregularities in depth. This information should be recorded to guide adjustments and maintenance in future plantings.

Changes to the seeding rate, depth, or settings that are outside the technical guidelines for the cultivar and the manufacturer should be evaluated by an agricultural engineer.

Calibration also requires safety precautions. Static tests must be performed with the machine supported and locked, in addition to the use of personal protective equipment and compliance with the manufacturer's standards.

According to data released in the technical material presented, the final definition of the seeding rate, planting period, and adjustment should consider the conditions of each property, the history of the plots, the type of soil, and the cultivar used.

Before planting, the producer must determine the seeding rate based on technical recommendations and the quality of the seed lot.

It is also necessary to check the discs, chains, tubes, bearings and other components of the planter.

The metering mechanism must be compatible with the seed size. Then, bench and field tests should be carried out to confirm the effective distribution rate. Uniformity between rows should also be checked, as well as the sowing depth and operating speed.

Finally, the stand should be monitored after emergence. According to data released in the technical material presented, this monitoring allows for the identification of problems in the adjustment and the improvement of subsequent planting operations.