Soybeans [Glycine max (L.) Merrill] have great economic prominence in the world, and soil management systems can directly interfere with their yield through changes in soil physical-hydric properties. Thus, the aim of this research was to verify the relationship between yield components, physiological traits, root development, and soil physical-hydric properties in soybean yields grown under conventional tillage and no-tillage systems. The experiment was carried out in Botucatu, SP, Brazil, with two treatments: soybeans grown under conventional tillage and no tillage. It is a long-term experiment, conducted since 1986. The main variables that influenced soybean yield were plant height, relative leaf water content, root dry matter, soil penetration resistance, and soil accumulated water infiltration. Physiological components of the plant and soil water showed a significant and negative correlation with soybean yield. On the other hand, the root development and soil physical components were positively correlated with soybean yield. However, the yield components were not significant. The no-tillage system resulted in 7.8% more soybean productivity compared to conventional tillage. Soybean yield depends on the physical properties and the water storage capacity of the soil, as well as on the physiological traits and the root development of the plant.
No-tillage cover crops contribute to better soil quality, being able to replace mechanized tillage management. This observation can only be made after several years of adopting conservationist practices and through research on soil–plant relationships. The objective of the research was to verify the relationship between the production components, physiological, root development, and physical-hydric properties of the soil in the yield of soybean grown in succession to different cover crops or with soil chiseling. The experiment was carried out in a randomized block design with four replications, comparing the cultivation of sunn hemp (Crotalaria juncea) and millet (Penninsetum glaucum L.) as cover crops and a treatment with soil chiseling. The evaluations were carried out during soybean (Glycine max L.) cultivation in the 2019/20 summer crop, that is, after 17 years of experimenting started in 2003. Rotation with sunn hemp increased soybean yield by 6% and 10%, compared with millet rotation and soil chiseling. The species used in crop rotation in a long-term no-tillage system interfere with the physical and water characteristics of the soil, affecting the physiological responses and soybean yield. The rotation with sunn hemp offers greater water stability to the plants and provides greater soybean yield in succession. Future research that better addresses year-to-year variation, architecture, and continuity of pores provided by crop rotation, and evaluations of gas exchange, fluorescence, and activities of stress enzymes in soybean plants may contribute to a better understanding of soil–plant relationships in long-term no-till.
Soil management systems directly interfere in the soil–plant relationship. However, there are still few studies evaluating the influence of long-term management systems on the physiological quality of soybean seeds. Another little-known topic is the influence of pre-harvest desiccation on the physiological quality of soybean seeds, especially on seed longevity. Thus, the aim of this research was to evaluate the physiological quality of soybean seeds cultivated under conventional tillage and no-tillage systems with and without desiccant use. The experiment was carried out in design is a split plot in a randomized complete block design. The treatments consisted of soil management systems (conventional tillage and no-tillage), with and without pre-harvest desiccation. In the treatment with desiccation, the herbicide Paraquat was applied, when the plants were at the R7.3 phenological stage (most of the seeds had a yellowish coat, with a shiny surface and were already detached from the pod). Seed germination, vigor (first germination count, seedling dry mass, seedling length, time to reach 50% germination (T50), seedling emergence and emergence speed index) and longevity (P50) were evaluated. Seeds cultivated under conventional tillage showed greater vigor for most traits evaluated, with values of T50 and seedling length higher by 24.39% and 24.77%, respectively, compared to NT. In addition, non-desiccation increased the seedling length and dry mass, in 15.45% and 21.59%, respectively. The use of desiccant aiming at seed vigor is dependent on the soil management system. Soybean seed longevity was superior in the no-tillage system, but desiccant application reduced seed longevity.
Soil management systems can directly interfere with crop yield via changes in the soil’s physical and hydraulic properties. However, short- to medium-term experiments of conduction do not always demonstrate the modifications of the management systems in these properties. Thus, the aim of this study was to evaluate the physical properties of the soil in a long-term management system and to relate it to the storage and availability of water to plants, verifying its effect on soybean yield. The experiment was conducted in randomized blocks in a split-plot scheme with four replications. Plots were composed by soil management (conventional tillage and no-tillage), and subplots represented three soil depths (0.0–0.1, 0.1–0.2, and 0.2–0.4 m). The soil’s physical and hydraulic properties, root development, and soybean yield were evaluated. The no-tillage system not only presented higher bulk density and soil resistance to compaction up to a depth of 0.2 m but also greater root development. This management also did not affect the process of water infiltration in the soil and presented an increase in soybean grain yield by 6.5%. The long-term no-tillage system (33 years) offers less risk of water stress to soybean plants; it contributes to greater grain yield of this crop when compared to the conventional tillage system.
There are few studies about the influence of fruit maturation and post-harvest resting on seed composition, which can be necessary for seedling development and future establishment. Thus, the objective of this study was to evaluate the effect of maturation and post-harvest resting of fruits on the macronutrient and protein content of sweet pepper seeds. The experimental design was a randomized block, with eight treatments, in a 4 × 2 factorial arrangement. The first factor was fruit maturation stages (35, 50, 65 and 80 days after anthesis), and the second, with and without post-harvest resting of the fruits for 7 days. The characteristics evaluated in seeds were the dry weight of one thousand seeds, macronutrient content, and content of albumin, globulin, prolamin and glutelin proteins. There were reductions in K, Ca and Mg content, and an increase in seed content of albumin, globulin and prolamins as a function of the fruit maturation stage. Post-harvest resting of the fruits provided higher Ca content and protein albumin in seeds. The decreasing order of macronutrients and protein content in seeds, independent of fruit maturation and resting stage of the fruits, was N > K > P > Mg > S > Ca, and albumin > globulin ≈ glutelin > prolamine, respectively.
Herbicides with desiccant actions may be used to anticipate the harvesting of soybean seeds. This technique aims to minimize the negative influence of biotic and abiotic factors on seed physiological quality at the end of the plant cycle. However, forced seed maturation with the application of herbicides can compromise the acquisition of seed quality components, especially longevity. Thus, the objective of this research was to evaluate the physiological quality of soybean seeds subjected to forced maturation with desiccants. The experiment was performed in a completely randomized design, with a treatment consisting of soybean plants subjected to the application of herbicides with desiccant action at stage R7.3 and another that underwent the natural process of maturation, that is, without herbicide application. The herbicide used was Paraquat. Seed germination, vigor (first germination count, dry mass, seedling length, time to reach 50% germination(t50), emergence index, and emergence speed), and longevity(P50) were evaluated. The herbicides did not affect germination (normal seedlings). However, the acquisition of vigor and longevity, and the preservation of seed vigor during storage were affected. Thus, the results indicate that the application of herbicide with desiccant action interrupts the process of acquisition of seed physiological quality, notably longevity in soybean seeds.