Sustainable Tillage and Sowing Technologies

Environmentally friendly and energy-efficient farming technologies are integrated into agricultural production as cutting-edge technologies that provide the greatest economic, energy and environmental benefits. The purpose of these technologies is to limit the mechanical and chemical impacts on the soil and crops, ensure the renewal of soil productivity, protect the environment, promote the rational use of materials, energy and labor resources, produce healthy products, and guarantee the efficiency of agricultural production. New environmentally friendly farming technologies are not possible without new tillage and sowing techniques, which also require higher soil and environmental protection requirements, the most important of which are to not deplete the soil, stop the decline of humus and soil degradation, reduce the leaching of nutrients and the most fertile soil particles, protect the soil from erosion and the breakdown of its structure, and to promote natural biological processes in the soil. For example, in Faligowska et al.’s [1] investigations, based on long-term (since 1999) tillage practices, summer pea fixed nearly twice the amount of N in stubble-cultivated plots and around three times the amount in nontilled plots compared to deeply ploughed ones. Ploughless and no-till systems had 2.2 times higher harvested pea seed yields.

The Special Issue “Sustainable Tillage and Sowing Technologies” is a collection of seven articles looking at different crop sowing–seeding times and methods under different climate conditions.

Sowing depth is one of the most important agro-technological parameters. The sowing or seedbed depth varies and mainly depends and on the site-specific soil, microclimate conditions and crop biology. In Romeneckas et al.’s [2] case study, sowing (seedbed) depth and other seedbed parameters were determined using the Kritz method (1979) adapted to Lithuanian conditions. This method includes measurements of seedbed top and bottom roughness, seedbed depth, moisture content, structural composition and sowing uniformity. The seedbeds of winter and spring wheat, spring barley, sugar beet, maize, winter and spring oilseed rape were analyzed in this study. Plenty tillage systems from deep ploughing, stubble cultivation, rototilling, chiseling, subsoiling and no-tillage were used for seedbed formation. Sowing systems from conventional to direct and scattered (3-D) were also described. The tested seedbeds’ depths varied from 14 mm (sugar beet) to 77 mm (maize). A case study showed that, in most cases, with an increase in the sowing depth to more than the optimum, the moisture content in the seedbeds significantly reduced. The sowing depth was also correlated with the seedbeds’ top and bottom roughness and aggregate-size distribution, but the direction of the relationships depended on the crop species and maximum sowing depth. The sowing depth also correlated with seed germination, crop development and productivity. The direction of these relationships varied between crop species, weather conditions, tillage and sowing technique.

Authors also tried to observe the existing methods and technic for adjusting of sowing depth automatically according to the site-specific conditions [2]. In conventional sowing machines, sowing depth is regulated manually before sowing. In new-generation drills, tractor suspension mechanisms, different hydraulic cylinders, electro-hydraulic downforce control systems, electric motors with a mechanical drive, pneumatic systems, and magnetorheological cylinders are used as the main sowing depth adjustment mechanisms. Such mechanisms can help to regulate sowing depth depending on the changing field-specific conditions, such as soil structure, texture, penetration resistance, organic matter and moisture content. Field site-specific conditions can be detected by different sensors before sowing or just during sowing operation. Ultrasonic, optical, strain, resistance, electromagnetic, electrical and others are covered in this study. The authors concluded that the newest on-the-go sowing depth variation systems have measuring system (sensors) and dynamic sowing depth control mechanisms (actuators). The most valuable are noncontact optical and electromagnetic induction sensors, which can measure the amount of soil organic matter and moisture and the temperature of soil. Maps of field soil properties can be used in such sowing technologies.

Sowing time is another important agro-technological parameter with high potential to improve crop germination, development and productivity. Butkevičienė et al. [3] investigated the impact of sowing time on the productivity parameters of spring oilseed rape. These investigations are important, because rape oil is one of the most consumed in the world, after soybean and palm. Oilseed rape productivity depends on the variety’s genetic characteristics, but also on the environment and meteorological conditions. So, sowing time and the length of the vegetative season closely are correlated with the success of rape cultivation, because the optimal sowing time could improve the adaptation of different varieties to site-specific vegetative conditions. The authors sowed spring oilseed rape 8–10 times between the beginning–middle of April and the beginning of June every 7 days. The results showed that the highest yield of seeds was achieved after sowing in middle and late April, when the sum of active temperatures (≥10 °C) during vegetative seasons was from 1830 to 2100 °C.

Soil salinity and lack of precipitation are important challenges in agriculture. Crop planting methods, irrigation regimes and soil organic or inorganic additions could limit the negative impacts of soil salinity on the crop productivity. In Egypt, a group of scientists investigated the complex effects of soil amendments (compost and zeolite), the raised-bed planting method, and irrigation rates (from 5% to 10% of leaching fraction) on the physicochemical properties of soil, as well as wheat and maize yields [4]. The combination of the compost and zeolite use, 10% irrigation rate and raised-bed planting method decreased the soil salinity, increased wheat yield by 16.0% and maize by 35.0% compared with not additionally amended plots, irrigated with a 5% leaching fraction rate and planted conventionally. So, this environmentally friendly multi-functional agricultural technology with soil amendments and raised-bed planting for much effective irrigation water distribution and use was effective to reclaim saline soils and improved wheat and maize cultivations in arid climate conditions.

In Eastern India with a total rainfall up to 155 mm per cropping season, Midya et al. [5] tried to prove the effectiveness of complex nutrition + water-saving seeding techniques in rice cultivation. Rice was cultivated aerobically, flooded and under intensification system (SRI) cultures. As sub-treatments, different minerals and organic and bio-organic fertilizers were applied. According to the results of investigations, conventional flooded rice cultivation demonstrated the lowest water productivity. The cultivation of rice in aerobic and conventional conditions decreased the yield of rice by 24.6% and 20.9% compared to SRI. Rice cultivation in anaerobic conditions led to a significant decrease in nutrient uptake and use efficiency compared to rice under SRI and flooded conditions [6]. However, the aerobic method was improved the efficiency of physiological nitrogen use and improved soil microbial quality. The authors concluded that the SRI method was the most efficient in terms of saving water, soil nutrient enrichment and uptake, and increasing the soil microbiological quality during rice cultivation, and proved Kassam et al.’s [7] insights correct.

In another region of India, West Bengal, researchers investigated effective water use methods, under subtropical humid climate conditions with an average annual rainfall of 1500 mm [8]. They investigated the effects of different raised-sunken beds and irrigation techniques on the water and rice + okra binary-crop productivity. Rice was grown in every second sunken bed and okra—raised by 20 cm beds with different widths as the experimental treatments. Two crop irrigation treatments were applied: continuous standing water with standing water of 5 cm depth; alternate wetting drying at 3 ± 1 day interval for rice in sunken bed. The authors concluded that water productivity in okra + summer rice cultivation with mixed raised-sunken beds increased by two times compared to traditional rice cultivation. Additionally, a raised-bed land configuration saved up to 45% of irrigation water. The most productive rice was grown between the shortest (1:3 ratio) raised beds with okra and in conditions of continuously standing water. So, rice + okra binary crop (“more crop per drop” principle) and raised-sunken beds as water-saving techniques would guarantee higher crop productivity per unit of land area with less water used per production unit (“more food with less water”).

Das et al.’s [8] words perfectly summarize our Special Issue. They pointed out that effective water use (and also precise observations), conservation and productivity will be the most important factors in the future agriculture. Water productivity (and also storage) in agriculture can be improved through the increase in crop diversification, more advanced abstemious soil and water management methods. I absolutely agree with this position. Moreover, the main task of crop seedbed formation methods and sowing time optimization is to provide plants with the most favorable conditions to use water, which is necessary (and mainly so uneven distributed) for the vegetation.