Continuous Rotation of Three Large Biomass Crops With High Bioconcentration Factor of Cadmium Can Effectively Repair Contaminated Farmlands

Traditional phytoremediation is one means for remediation of heavy metal pollution. For developing countries, the key factor in promoting the practical application of phytoremediation in polluted soils is selecting suitable plants tolerant to heavy metals and using these to produce products with economic value. A chicory-tobacco-peanut, three-season, rotation field experiment was carried on the utilization and remediation of cadmium (Cd) in contaminated farmlands. The results showed that all three crops had a strong capacity to accumulate Cd, with bioconcentration factors of chicory, tobacco, and peanut 6.61 to 11.97, 3.85 to 21.61, and 1.36 to 7, respectively. The yield of total dry biomass and phytoextraction efficiency for Cd reached 32.4 t ha-1 and 10.3% per year, respectively. The aboveground tissues of the three crops accounted for 83.9–91.2% of the total biomass in this rotation experiment. The content of peanut grain and oil met the National Food Safety Standard of China (0.5 mg kg-1, GB 2762-2017) and the Food Contaminant Limit of the European Union (0.1 mg kg-1, 18812006). Therefore, in addition to being used for phytoremediation in contaminated soils, this crop rotation system can also lead to economic benefits for local farmers.

Tropicalization of canola: commercial hybrids show potential for cultivation in the Brazilian Cerrado

Canola is a potential feedstock for the production of biodiesel due to its high levels of energy efficiency. However, Brazil has not yet consolidated its production as typical of temperate regions. Thus, the objective of the study was to evaluate the agronomic performance of canola hybrids in the tropical conditions of the Brazilian Cerrado in order to select promising candidates to contribute to the expansion of canola culture in the country. Eight commercial canola hybrids were evaluated for seven agronomic traits, in three experiments with varying water conditions. The data obtained for each variable were subjected to joint analysis of variance and the averages compared using the Scott-Knott test. The grain yield of the evaluated hybrids was higher than the national average, which includes plantations only in the southern region. The hybrids that stood out in grain yield were Hyola 61 and Hyola 76 followed by Diamond, which besides presenting a high magnitude for this characteristic, was less precocious even in dry conditions. Due to its characteristics, the Diamond hybrid can be considered the best option to be inserted in the crop rotation system. These results are promising and reveal adaptation and cultivation potential of these hybrids in the Brazilian Cerrado. Highlights The yield of canola grains in the experiments was promising as the values ​​achieved were above the national average. Hyola 61, Hyola 76 and Diamond showed prominent grain yield in relation to the other hybrids investigated. Diamond presented high grain yield and shorter cycle, thus being considered the best option for the crop rotation system. For the Brazilian Cerrado, the hybrids Hyola 61, Hyola 76 and Diamond are valuable alternatives for planting.

Corn and Soybean Productivity in Succession to Family Coverage Plants Poaceae and Fabaceae

The use of soil cover plants has varied effects on crops grown in succession, depending on the cover plant used. The objective of this study was to evaluate the effect of soil cover plants from the Poaceae and Fabaceae families grown in the autumn and winter on yields of corn and soybean grown in succession. The experiment was carried out for two years and the experimental design used was randomized block design, with six replications. Both in the first year and the second, the plots consisted of the cultivation of corn or soybeans on the different biomasses of four cover crops cultivated in autumn and winter intercropped with corn. The cover crops were two Poaceae plants (black oats and brachiaria) and two Fabaceae plants (forage pea and white lupine). The production and productivity parameters of summer corn and soybean commercial crops were evaluated Cover plants of the Poaceae (black oat and brachiaria) and Fabacea (pea and white lupine) families intercropped with corn grown in autumn-winter did not affect their yield components and yield; as well as the productivity of soybeans in succession. According to the results of this work, the cultivation of black oat, brachiaria, forage pea and lupine increases the number of species that the farmer can cultivate intercropped with corn, favoring the crop rotation system in no-till.

Interference of post-emergent herbicides with wheat (Triticum aestivum L.) productivity parameters/ Interferência de herbicidas pós-emergentes sobre parâmetros produtivos do trigo (Triticum aestivum L.)

Wheat is the most important income-generating crop in southern Brazil during the cold season. It also contributes to the crop rotation system and increases the yield of successive crops. During its growth cycle, herbicides are used to control weeds, which are the main factor limiting wheat productivity. Further, high costs of weed control directly affect crop economic returns. The objective of this study was to evaluate the effect of the application of two herbicides, namely, 2,4-D and iodosulfuron-methyl, on the productivity of two wheat cultivars during the nine different stages of crop development. The most suitable crop stage for herbicide application, as described in the corresponding label on the package, is at the beginning of tillering. 2,4-D had a significant impact on productivity parameters, reducing the number of tillers, the number of ears, and the number of tillers without grains, while increasing the number of tillers without ears and ears without grains, indicating greater phytotoxicity and, ultimately, reducing crop productivity. Conversely, iodosulfuron-methyl showed greater selectivity to the wheat cultivars tested and caused a much lesser impact on the productivity parameters measured.

Code of best agricultural practices: general characteristics, disadvantages, ways of improvement

The article provides a scientific and theoretical analysis of the Draft Code of Best Agricultural Practices' content and its significance for the legal support of ecologization of agriculture in Ukraine. We have studied the content of the Draft Code of Best Agricultural Practices and the Draft Code of Proper Agricultural Practice. It was identified the deficiencies in the wording of the scope of these Draft Codes. It is also proposed to extend the Draft Code of Best Agricultural Practices' content to all agricultural producers without imposing any restrictions. It is noted that in the text of the Draft Code of Best Agricultural Practices, it is mandatory to enshrine the provision on voluntary application (based on paragraph 1 of Article 4 of Council Directive 91/676 / EEC on the protection of waters against pollution by nitrates from agricultural sources of 12.12.1991). Also, we have identified the shortcomings of the provisions of the draft Codes regarding land use management regulation, including the use of the crop rotation system. It is concluded that it is inexpedient to duplicate in the Draft Code of Best Agricultural Practices the legislation governing the organization of crop rotations. It is proposed to limit the indication to the relevant regulations. It is concluded that in parallel with the implementation of the Draft Code of Best Agricultural Practices, work should be carried out to implement the cross-compliance approach in Ukraine. This will motivate agricultural producers to comply with the Code of Best Agricultural Practices provisions and contribute to agriculture's ecologization. Keywords: agriculture, Code of Best Agricultural Practices, legal support, ecologization of agrarian activities, nitrates, mineral fertilizers, soil

WEEDS IN SOYBEAN CROP AFTER ANNUAL CROPS AND PASTURE

The use of crop practices to reduce the weed community is an ally to integrated weed management. Given this, the study aimed to identify a composition and weed infestation in a soybean area under different predecessor crops implanted in different years. The experiment was carried out in the 2019/2020 harvest in Dourados, MS. The experimental design was a randomized block with nine treatments. The treatments were composed of autumn-winter crops. The area with predecessor cultivation: corn-Brachiaria intercropping; cowpea beans; single corn; an area with predecessor cultivation of Brachiaria as pasture for one year; two years; three years; four years; five years, and six years. All treatments were followed by soybean cultivation in the 2018/2019 harvest and an intercropping with corn and Brachiaria in the 2019 off-season harvest. There was a difference in the absolute weed infestation between the evaluated areas. Treatments with corn and cowpea had greater weed infestation. However, areas with pasture or intercropping with corn and Brachiaria showed less infestation, especially in areas with Brachiaria grown in the off-season for more than two years. The weed species composition differs between the areas evaluated. The implantation of a corn-Brachiaria intercropping in the off-season under a crop rotation system, especially in areas with Brachiaria grown in the off-season for more than four years, reduces the weed infestation.

ZNAČAJ PREDUSEVA ZA PRODUKTIVNOST KUKURUZA

The advantages of the three- and four-crop rotations in relation to the two- crop rotation are reduced frequency of soil tillage, and thus savings in energy sources, lower intake of mineral nitrogen fertilisers and the amount of applied herbicides. The aim of the present study was to indicate the importance of a proper alternation of crops in the three-crop rotation system and to compare the advantages of cultivation of maize after winter wheat or soybean in terms of reducing weediness, formation of the harvest index and grain yield. Results of long-term studies have shown that the crop sequence significantly contributed to the decrease in fresh biomass of weed and the increase in the harvest index and grain yield in the maize-winter wheat-soybean rotation in relation to the maize-soybean-winter wheat rotation.