MC Electronics: precision systems
for agriculture

Seed drills sensors: the importance of sensors for an effective seeding control system

Agriculture sensors on agricultural machinery: the needs of the development of this technology An important aspect is how the quality of the information we have determines the accuracy of our choices: using an effective seed drills sensors technology gives the possibility of continuous monitoring of the entire sowing, and not only with single samples of the plot during the sowing, but with constant monitoring of the entire activity that we are going to carry out, multiplying the samples in our possession and also providing us more data to examine, this turns into more information for the future choices that we will take. Furthermore, an aspect that requires more and more attention in a modern farm It’s the possibility of making two aspects that have always been linked independent, the quality of the work produced and the experience of the producer: the knowledge of the variables that come into play during sowing as the knowledge of the lands on which we are going to invest, of the seeder with which we are going to operate, of the techniques to obtain the maximum result and many others, have determined in the past a univocal link between the final result and the farmer who has performed. In a modern conception of business management, and therefore of interchangeable human figures who can carry out the same operations, but at the same time with different knowledge and backgrounds, technology comes in handy: supporting those who interface with the machine with objective and clear information, we reduce the possibility of making wrong choices, and increase the production capacity of the machines and finally to reduce the cost of training. Taking a short step back and looking for the reasons why today the choice to invest in agriculture sensors on a modern seeder such as the Blockage sensors produced by MC Elettronica, composed of an infrared optical photocell coupled to a microprocessor, it is necessary to understand how the figure of the farmer is profoundly transformed, evolved and increasingly comparable to the figure of a business manager aiming for success, introducing the concept of agricultural entrepreneur. From this point of view, it is clear that the common goal is to do more and better with fewer resources, considering each variable so far evaluated as negligible. Picture 1 – Application of Blockage Sensor infrared photocells for flow monitoring in a pneumatic seed drill. The seed and its needs However, before dealing in more detail with the technology, it’s better to have a deep knowledge of the material we are managing in the field which in this case is the seed. Planting in the ground is one of the most technological agronomic operations that has the purpose of guaranteeing agricultural production. The seed is a biological unit equipped with everything needed to be able to germinate, but in order to do so it must be placed in the right conditions. In fact, an interesting characteristic that is still partly not fully clarified is the ability of the seed to remain alive and to germinate despite the very low humidity content, together with the partial cellular disorganization. However, in the presence of soil moisture it absorbs the necessary water and except in particular conditions, the metabolic processes are triggered which lead to germination supported by the reserve substances present. This very delicate field phase requires the best agronomic technique. Indeed the water and its movement towards the seed are the key factor here: the volume of soil from which the seed absorbs water does not exceed a sphere of about 1 cm in diameter representing the microenvironment which directly influences germination but with variable effects according to the cultivated species. Obviously the flow of water from the soil to the seed is within a balance of factors including: contact between seed and moist soil; seed structures; factors that modify the amount of soil moisture (climate, soil type, agronomic technique, organic substance present). Figure 2 – A) elements coming from above ground; B) layer of soil covering the seed; C) seed deposited in soft soil and in purple seeding depth; D) soil underlying the seed (worked or hard). Agrotechnics and sowing As is well known, agrotechnics is the set of choices that the farm must define so that it is possible to guarantee agricultural production and the company budget in the management of the soil and crops. Among the many factors that must be known in order to be successful in sowing management, we can indicate for example: choice of seed, sowing period, type of soil management and tillage. In this context, however, we want to focus on the sowing rates, a particularly important aspect to manage in the field of agronomic technique which directly influences the management of the sowing site, the cost and the final production. Taking wheat as a reference, for example, in the literature it is defined as the quantity of seed to be used per square meter depends on the density of plants to be obtained, on the average weight of the kernels, on the factors on which germinability in the field depends. The latter is then influenced by other factors such as soil preparation, low temperature in late sowing, low humidity, seed or seedling predators. Therefore, as every farmer knows, it is good to raise the dosages of seed compared to those actually necessary in optimal conditions. However, there must be a balance between the availability of production factors (water, nutrients) and the sowing rate. In fact, it is not obvious that high plant densities guarantee high productions especially if the factors are severely limiting, first of all water shortages, just as excessive plant density determines a lower resistance of the culms to lodging. It is clear that the dose must therefore be commensurate with the agronomic context, the fertility of the soil and the availability of production factors so that in fact it is the balance between all the limits present in relation to the obtainable production that must be optimized. Picture 3 - An agronomic technique consistent with the agronomic context and the defined objectives are a solid bridge that leads from the seed to agricultural production. In this context, the seeder is strategic in contributing to the agronomic result. Seed drills mechanics Seed drills, compared to planters, allow to sow crops (wheat, legumes, etc) with very reduced spacing between crop rows. In this regard, seed drills have a mechanical distributor with seed falling by gravity or in a pneumatic version which exploit an air stream to transport the seed to the ground. In both cases, the semen dosage is traditionally of volumetric type. In this context the dosers and distributors, positioned at the base of the hopper in a special housing, receive the seed and transfer it to the ground dosing the product, they are available in various designs to adapt them to the type of seed to be sown including universal grooved cylinders, with toothed rollers. Picture 4 – an example of the seed transport and dosing system with seed sensor in a pneumatic seed drill. To define the seeding dose it is possible to act both in the choice of the size of the distribution reels and in the rotation speed of the distributor regulated by mechanical transmissions or with electric or hydraulic motors. In these systems, the choice of materials, geometries and systems that minimize damage and breakage of the seeds and therefore leave the germinative strength of the seed unchanged, already subject to natural factors as indicated above, must also be considered. In any case, the seed, once released from the distributors, enters in pipes which, either by gravity on the mechanical machines, or with a high-speed stream of air, guide it towards the seed rows on the ground by the openers (of various types). Picture 5 – an example of high performances pneumatic seed drill. Picture 6 – some examples of distributor reels of various profiles for pneumatic seeders moved by precision digitally controlled electric motors. One revolution in the distributor corresponds to a certain dose according to the volumes defined by the grooves. The geometry of the surface is designed to adapt to different seeds.