Direct planting of upland rice

Study shows lower fuel consumption, greater area sown per working time and similar production in the Upland Rice Direct Planting System in relation to conventional planting.

When choosing a management system, it is essential to consider the production cost, crop productivity and the physical conditions it promotes in the soil. The direct sowing system is characterized by implanting a crop with soil mobilization only in the sowing line over the soil cover from previous crops. This eliminates soil preparation steps such as periodic tillage operations (plowing and harrowing) and introduces lighter operations such as desiccating the area with herbicides, managing cover crops and sowing over crop residues from previous crops.

An interesting alternative for rice cultivation in Vale do Ribeira (SP) has been minimum cultivation with scarification after desiccation, allowing the maintenance of part of the soil cover on the surface and minimizing the effects of restricting development. rice root, as it is a crop that is more sensitive to soil compaction.

The correct use of agricultural machines and implements is crucial for the performance of the equipment and the economic viability of the business, regardless of the production system adopted, as it allows an increase in machine productivity and a reduction in production costs. The success of the project is related to the chemical and physical conditions of the soil, as well as the performance of the motor-mechanized sets with an increase in the area worked per hour (effective field capacity) and a reduction in energy expenditure, especially fuel.

Production systems have different peculiarities, with the conventional sowing system (PC) being the oldest and which tends to offer conditions for greater losses of water, soil and nutrients and greater fuel expenditure per hour (hourly consumption) and by area (operational consumption). Minimum cultivation (MC) allows for a reduction in soil disintegration, which is essential for reducing losses of soil, water and nutrients, in addition to resulting in fuel savings compared to conventional cultivation. The direct planting (PD) system contributes significantly to maintaining the chemical and physical characteristics of the soil in the medium and long term; with soil mobilization only in the sowing line, it changes the demand for strength and power, reduces fuel consumption and tends to result in greater performance of motor-mechanized sets.

The work developed at Unesp – Campus de Registro (SP), since 2011 with summer soil preparation systems (PC, CM and PD) and direct planting of winter crops (corn, canola and triticale) aims to study strategies for conservationist rice production, aiming to optimize the system, maintaining or improving soil quality, improving the performance of the motor-mechanized sets involved in production, reducing costs and, consequently, increasing the producer's income.

The data presented in this work refers to the summer implementation in the 2013/14 agricultural year, when the force on the drawbar (kN), the hourly consumption (in L/h) and the operational consumption (in L/ha) were measured. of the operator-tractor-seeder-fertilizer set during the sowing operation. Seedling height at 20 days after sowing and rice grain production, corrected for 13% humidity, were also determined.

Figure 1 shows the average data obtained for the test, where the forces required on the tractor's drawbar for the sowing operation were compared between the soil preparation systems in the summer, indicating lower force requirements for sowing in the direct planting system. (PD), while the forces required for the operation were similar for minimum cultivation (CM) and conventional cultivation (PC).

Considering the sowing operation common to the three systems, it can be seen that the lower force required by the mechanized set in the PD resulted in lower hourly consumption and lower operational consumption, compared to the PC and CM systems, which also presented similar consumption.

This relationship can be seen in Figure 2, where it can be seen that the amount of fuel consumed per hour (C hor.) increases with the increase in the force required for traction, which is to be expected, since greater forces are overcome with the highest consumption of energy provided by the fuel. Diesel oil consumption per hectare is more influenced by the effective operational capacity of the motor-mechanized set (CcE), showing a weak correlation with the force demanded on the drawbar.

At a time when attention is focused on fuel prices and the reduction in energy consumption, it is worth highlighting that the diesel oil savings per hour worked in this experiment were 1,39L in PD compared to PC and 0,39L of PD in relation to CM, which is equivalent to savings of R$3,78/h and R$1,06/h respectively, considering the average price of diesel oil in the first half of March 2015 (R$2,719/L ), according to the ANP. The reduction in fuel costs per area (C op.) was 17,6% of PD in relation to PC and 20,4% of PD in relation to CM, which becomes considerable when it comes to the production of a product of the Brazilian basic food basket.

The values ​​of sowing speed, operational capacity, represented by the effective field work capacity (CcE) and crop productivity, were similar for the three soil preparation systems, as shown in Table 1.

Average speeds were between 5,22km/h and 5,33km/h, suitable for planting the crop, which is between 4,5km/h and 7km/h depending on the machine model, type of soil, slope, among other factors. The increase in speed linearly and significantly increases the effective field capacity (CcE), as shown in Figure 3, which is expected, since the last variable is a directly proportional result between the real working width of the seeder and the speed of displacement thereof. It is also noted that hourly consumption decreases with increasing speed, due to the greater area worked per unit of time. Increasing the speed to the limits permitted for the area and crop tends to reduce fuel costs, identifying signs that PD tends to be more advantageous than other preparation systems in this work.

Regarding the productivity of rainfed rice, it was possible to notice that the three preparation systems showed similar productivity, which demonstrates, in this study, an advantage of the direct planting system in relation to the others, since fuel consumption is lower in the rice production operation. sowing, not yet considering the reduction in operating costs with machines by eliminating soil preparation operations.

The data collected for this study allows us to conclude that the direct planting system is more economical in the implementation of rice cultivation, with productivity similar to that observed in the minimum cultivation and conventional cultivation systems with soil repair, which leads to the best economic result for the producer.

According to the results of this work, it can be seen that rice cultivation has behaved positively in the direct planting system in Vale do Ribeira, even after three years of cultivation in this system, a period in which the literature points to a tendency for difficulty in root development of the crop and reduction in productivity in PD, indicating that for the Ribeira Valley, conservationist systems of rainfed rice production are options that must be considered and adjusted to the needs of the rural producer.

Different treatments used to develop the assay

Since the beginning of the project, the trial has been conducted with treatments in summer cultivation: conventional tillage, minimum tillage and direct planting.

Conventional preparation (PC) was carried out with a plowing harrow, leveling harrow and rice sowing with a seeder-fertilizer equipped with a furrowing mechanism, type of mismatched double discs, coupled to a tractor with 95,7kW (130hp) of engine power and front-wheel drive. auxiliary (TDA).

Minimum cultivation (MC) was carried out with desiccation of the area with 250L/ha of syrup and 8L/ha of glyphosate (p.c) associated with 2L/ha of 2,4-D, followed by subsoiling to a depth of 0,40m with subsoiler equipped with parabolic rods and a crushing roller and sowing with the same seeder-fertilizer and tractor.

The direct planting (PD) system was carried out by desiccating the area with the same mixture used in CM and sowing the rice with the same motorized set. After harvesting the rice, in winter cultivation the area is desiccated with the same volume of syrup used in summer, 6L/ha of glyphosate and 2L/ha of 2,4-D. The crops implemented in a direct planting system are CA – Canola; TRI – Triticale; and treatment kept fallow (without winter cultivation). Winter crops were implemented in May 2013 and continued until the end of the cycle, when they were managed to establish soil cover.

José Alexandre da Silva Junior, Paulo Henrique Watanabe Nakagawa, César Henrique de Jesus, Artur José de Santana, NetoCarolina Tiemi Suguinoshita Rebello, Wilson José Oliveira de Souza, LAMMEC - UNESP

Article published in issue 153 of Cultivar Máquinas.