The objective of this research was to assess soybeanproductivityinsuccessiontocovercrops grown during the winter, in addition to assessing physicalproperties macroporosity (Ma), microporosity (Mi), total porosity (Pt), soil density (Sd) and aggregate stability by means of the following variables: aggregate stability index, geometric mean diameter and weighted mean diameter after soybean crop cultivation. The experiment was conducted in the municipality of Quatro Pontes, PR, using a randomized-block design with six treatments and four replications. Treatments consisted of soybean crop grown on top of different cover plants’ haystack: black oat, black oat + forage turnip, forage turnip, black oat + forage pea, forage pea and control. Significant differences were observed for soil macroporosity and density. At the depth of 0.10 m, the highest Ma was observed in the area with oat and oat + turnip haystack. At other depths, all covercrops were superior to control. Treatments with covercrops were efficient in reducing soil PR. As for soil aggregation, the treatment with pea was superior to control for weighted mean diameter. The treatments with soybean sown after intercropping obtained greater mass, as well as higher productivity.
ABSTRACT: Coffee cultivation has great socio-economic relevance in Brazil for the employment and income generation and there is currently a constant search for sustainable management techniques. Among them, we can mention the use of covercropsandsoil bioactivators. However, studies relating the use of these two techniques are still incipient. Based on this, the objective of this research was to evaluate the effect of the Penergetic® bioactivator associated with different covercrops on chemical properties of soiland coffee productivity. The experiment was carried out in a coffee field with Catuaí Vermelho cultivar IAC 144, in a randomized block design in a factorial scheme 4 (soilcover) x 2 (use or not of the Penergetic® bioactivator), consisting of control (without plant cover); oats (Avena strigosa) + forage turnip (Raphanus sativus ); oats (Avena strigosa) + forage turnip (Raphanus sativus ) + lupine (Lupinus albus) + rye (Secale cereale) + vetch (Vicia sativa); Brachiaria brizantha (Urochloa brizantha), associated or not with the use of the Penergetic® bioactivator. The experiment was conducted for 6 months and after that period, the chemical properties of soil, the nutrient contents of the coffee plants, the development of the branches and the coffee productivity were analyzed. Data were analyzed by the Scott Knott test at 5% probability. It was verified the interaction between covercropsand the use of the Penergetic® bioactivator, positively influencing soil chemical characteristics, coffee nutrition andproductivity.
considered the threshold value for plant development, especially in periods with high soil moisture, due to the restricted root aeration (Tormena et al., 1998). This Ma value in the inter-row position indicated compaction, confirming the origin of this effect, i.e., machinery traffic. Macroporosity was negatively correlated with Bd (r = -0.87**, Table 2) as also reported by Becerra et al. (2010). More macropores were observed in the SS than in the BO and MC treatments, in the surface layer (0.00-0.05 m) and inter-rows. The MC treatment had more macropores than BO, which may be related with the root systems of the cover species. On the other hand, the values observed in the rows were adequate, particularly in the 0.00-0.05 m layer, which was equivalent to the NF, and indicated a good structural condition for the growth of grapevine roots. The amount of microporosity (Mi) in vineyard soil ranged from 0.36 to 0.42 cm 3 cm -3 and was 0.40 cm 3 cm -3 in the NF
The effect of covercrops on SOC contents and SPQ frequently depends on cover crop species, soil texture, initial SOC contents, climatic conditions, and the amount and characteristics of the belowground development (Ding et al., 2002; Blanco-Canqui et al., 2015). Some authors found that soils from the Pampas region with high silt content have a low probability of recovering its topsoil porosity after several years of NT, even with higher organic carbon contents in surface layers (Taboada et al., 1998). The structure of these soils has low resilience (Taboada et al., 2008), affecting their ability to recover, even when more adequate management practices are applied. Thus, though covercrops are thought to increase SOC and positively affect SPQ, documentation is limited and needs to be broadened under different soil textural classes and crop species (Blanco-Canqui et al., 2015). Information about the effect of covercrops on SOC fractions obtained by chemical fractionation andin depth is scarce. Information on the potential of covercropsto accumulate SOC in depth is also scarce (Blanco-Canqui et al., 2015). Another aspect of SOC distribution is its spatial variation within a plot. There is literature on how SOC varies with topography, but there is little information on how it varies within short distances. In this sense, differences between the row and the inter-row of the previous crop can be expected to be found, as differences in root development and earthworms’ abundance between these positions have been reported (Mengel and Barber, 1974; Binet et al., 1997). In addition, establishing relationships between SOC fractions and other soilproperties that may define SPQ is still a challenge (Lal, 2009), that could provide valuable information to understand the functions of different SOC pools. The reviewed literature is summarized in tables 1 and 2.
ABSTRACT: Covercrops may have direct or indirect effects on the physicaland chemicalsoil attributes; these cropsplay a key role in the cycling of nutrients in the soiland add labile organic carbon, bringing economic and environmental benefits to the system. To study the effect of covercrops on the physicaland chemical properties of an Oxisol, a three-year experiment was conducted in a commercial vineyard located at Epagri’s Experimental Station in Videira, SC, Brazil. Different winter species (white clover, red clover, common vetch, turnip, corn spurrey, black oat, rye, and ryegrass) were sown in addition to treatments with manual weeding or mechanical mowing. Certain chemical andphysical attributes of soil were determined in samples collected fromlayers 0-0.1 and 0.1-0.2m deep on the vinerows and between rows, as well as the dry mass of winter covercrops. Few chemical andphysical attributes of the soil changed among winter covercropsand did not differ from the crops managed with mechanical mowing or hand weeding of spontaneous vegetation. Vine rows provided more adequate values of most physicaland chemical soil attributes.
Non-deformed soil samples were collected in the 0 – 0.10 m layer to determine the stability of the aggregates in water. After air-drying, the samples were sieved to separate 8- to 4-mm aggregates. For the wet sieving process, three 30 g samples were used in each repetition, 2 to determine the aggregation and 1 for moisture. The samples were moistened by capillarity on a filter paper and then, using water jets, transferred to the sieve set with 4.0; 2.0; 1.0; 0.5; 0.25 and 0.125 mm mesh to separate the aggregates according to size classes. Then, the sieve set was placed on Yoder tank and subjected to vertical stirring for 15 min at 30 oscillations per minute. The aggregate index adopted was the mean weight diameter (MWD) and geometric mean diameter (GMD), according to Kemper and Rosenau (1986).
Leguminous and grass covercrops have been successfully used to improve soilpropertiesin many region s (Lal et al. 1979). Beneficial effects of crop residues on soil surface under conservation tillage include increased water conservation andsoil aggregatio n (Lal 1976; Blevins et al. 1983). The ef fectiveness of covercropsin improving soil structure has been reported in many stud ies (Tisdall et al. 1979; Haynes and Beare 1997). Blanchart et al. (2004) studied the eff ects of grass roots on properties of a degraded Vertisol and reported that restoration of physicalproperties was quicker and greater in treatments with plants than in treatments without plants. Plants also played a dominant role through rhizosphere effects and possible carbon rhizodeposition. It has been shown that covercrops added organic matter to the soiland promoted soil faunal activity. Soil organic matter has significant impacts on soil physicochemical attributes. Organic matter also improves soil porosity and, therefore,
The rice plant population was affected by covercropsin the first and second years, whereas there was no effect in the third year. The lowest values were observed in the second year (Table 2). In the first year, higher rainfall (46 mm) between rice sowing and emergence was observed, compared to the second and third years (8 and 13 mm, respectively), thus the fallow treatment resulted in the highest plant population. In this case, the large amount of straw from covercrops was a physical obstacle tosoil moisture loss, and this decreased rice seedling emergence. Similar results were found in a study conducted at the same site andin the same growing season, i.e., initial plant density was greater when rice was sown after fallow than under three types of ryegrass straw management (Marchesi et al., 2011). Some practical strategies may minimize such limitations, like early herbicide application on covercropsand proper drainage, which were carried out in the present study. Conversely, rainfall in the sowing-emergence period of the second year was lower than in the first year, reducing soil moisture and the rice population insuccessionto fallow compared tocovercrops. In this case, the presence of straw was beneficial since it maintained soil moisture for a longer period. This effect was probably less important for rice grown insuccessionto ryegrass, due to the longer period (52 days) between crop desiccation and rice sowing, which may have reduced the amount of straw and increased moisture loss from the soil. Rainfall in the third year in sowing-emergence was higher than in the second year, although lower than in the first year. The higher aboveground biomass of covercrops combined with the higher rainfall maximized soil protection and reduced moisture loss, resulting in uniform rice emergence. The interval between herbicide application on covercropsand the time of rice sowing was the same in the second and third years. Thus, the differences lie in the aboveground biomass production, especially for ryegrass, without the same negative affect observed in the second year on the rice plant population. Although significant differences in rice plant density were observed, values were within the recommended interval, i.e., 150 to 300 plants per m 2
The cultivation of green manures with root systems that exploit different volumes of soil provides nutrient cycling (Boer et al., 2007). Since the decomposition of ve- getal debris of these plants release nutrients that contribute to increases in corn yields (Lara Cabezas et al., 2004) andsoybean (Carvalho et al., 2004) or maintaining the productivity of these crops (Andrioli, 2004; Bertin et al., 2005). According to Tanaka et al. (1992), the use of velvet bean, lablab and crotolaria as green manure provided significant increases in yields of rice, beans andsoybeaninsuccession. So, there is a need to adjust the production system, taking into account the previous cropsand sporadic mechanical descompactation of the soilto obtain the highest profit margin, as failure in rice and bean crop is often determined by compactation on the surface layer of soilin established non-tilage systems, altering the quality of the soil because it changes the flow of water and air and the dynamics of soil nutrients, promoting the reduction of productivity of cropsin several production systems.
Oxisols and Quartzarenic Entisols are the predominant soil classes in the Cerrado region, which require the use of management systems that favor the increase of organic matter in the soil (Pragana et al., 2012). Therefore, the no-tillage farming system (NTS) has been recommended, in order to improve the chemical, physical, and biological fertility of soil by the sowing of annual cropsandsoilcovercrops after soybean harvest (Carneiro et al., 2008). One of the greatest challenges in the use of this system insoybean crop areas is the assessment of option for the sowings of species that may favor biomass production and allow of increased soybean yield insuccession planting. In addition, considering that the succession planting of soybeanin the crop season, and corn in the off-season, has been the production model in these regions, for economic reasons and because of the available infrastructure (Calegari, 2002), it is important to evaluate intercropping systems between annual grain-yielding cropsandsoil-cover plant species that produce biomass to promote the wide-spreading use of these systems.
Abstract – The objective of this work was to evaluate the effect of winter cover crop species on the agronomic performance of soybean (Glycine max) cropped insuccession, under a no-tillage system. The study was conducted during three crop seasons (2011/2012, 2012/2013, and 2013/2014), with the following covercrops: white oat (Avena sativa), black oat (Avena strigosa), ryegrass (Lolium multiflorum), vetch (Vicia sativa), forage radish (Raphanus sativus), the intercrop black oat + forage radish, and wheat (Triticum aestivum) as the standard management. Forage radish and the intercrop black oat + forage radish provided greater soilcover rates after 30 days of planting, as well as dry matter production in the three crop seasons. After 45 and 90 days from desiccation, however, white oat and ryegrass showed the highest soilcover rate. Black oat and the intercrop black oat + forage radish provided higher soybean yield than the standard management with wheat, in the 2012/2013 and 2013/2014 crop seasons. Winter covercrops can significantly affect soybean yield insuccession, and black oat and the intercrop black oat + forage radish stand out for this purpose.
ABSTRACT: Covercrops are important for improving soil quality. However, soilproperties usually have some spatial dependence. Thus, this study aimed to evaluate the effect of winter covercrops on physicalproperties of soilandsoybean yields using thematic maps. Five winter treatments were used: black oats; intercropping 1 (forage turnips and black oats); intercropping 2 (forage turnips, black oats and common vetch); wheat; and control. Macroporosity, microporosity, total porosity, bulk density and water content of the soil from 0 - 0.1 m depths were evaluated after the winter cover crop management. Soybeans were sown over the entire area in the summer after the winter cover crop management, and the soybean yield was determined for each treatment. Maps for each treatment were created and compared to the control treatment using the relative deviation coefficient (RDC). The covercrops improved the total macroporosity of the soilin some regions of the study area. The black oats were more efficient at maintaining higher water content of the soil, and it can be used to decrease the bulk density.
Cover plants were sown using a spacing of 0.50 m between rows and, respectively, 6 seeds of C. ensiformis m -1 (100 kg ha -1 ), 15 seeds of C. cajan m -1 (15 kg ha -1 ) and 30 seeds of C. spectabilis m -1 (40 kg ha -1 ). After 65 days of cover plant sowing, the period preceding the full flowering of the covercrops, manual weeding was performed, keeping the cut plants on the surface of the soil, for straw formation. Then, maize (Hybrid 2B512 from Dow Agrosciences®) was sown in no-tillage system, with spacing of 0.50 m between rows and population density of 60000 plants ha -1 . The basal fertilization carried out at the time of sowing maize was 300 kg ha -1 with formulation 08-26-16. The inoculation of seeds with A. brasilense, using the commercial product Azototal®, according to treatments, was performed at dose of 0.5 mL kg -1 of seeds.
The use of swine wastes in the fertilization of crops is one form of adequate final disposal of wastes (Comin et al., 2013), since they are rich in nutrients that are essential to plants, such as phosphorus, potassium, calcium and magnesium (Manna et al., 2007; Celik et al., 2010). Thus, adequate and well planned application becomes an effective option to completely replace (Seidel et al., 2010; Sartor et al., 2012; Moraes et al., 2014) or partially replace industrialized mineral fertilizers (Passarin et al., 2016). This may reduce production costs and at the same time increase the availability of water and nutrients to plants.
Phosphorus did not differ among mound sections, but it was the nutrient that most differed between the termite mound and the adjacent soil, with higher values in the mound than in the soil. Although there was no significant difference, the P values at the distance of 0.50 m were almost the double of the values at 1.50 m from the mound, which indicates the influence of the mound on its adjacent soil (Table 2). Rückamp et al. (2010) quantified and systematized phosphorus forms in different sections of termite mounds (exterior wall, internal wall, and center) of different trophic guilds and soils in seven Brazilian ecosystems and concluded that termite activity results in a gross enrichment of phosphorus in labile form in nets, and the composition of P in termite constructions is reflected in their diet. According to Oliveira et al. (2012), the higher amount of P in termite mounds than in the adjacent soil is related to the amount of clay used in their construction, which hinders the loss of P available.
ABSTRACT – The objective of this study was to evaluate the chemical andphysical attributes of different soilcoverin a Oxisol with a strong wavy relief in the Atlantic Forest Biome, in which were selected three watersheds, employed with grazing (watershed P), forest (watershed M) and coffee (watershed C). Deformed and not deformed samples were collected in three depths for physicaland chemical characterization. The chemical characteristics of soilin different watershed studies presented low levels of fertility. It was observed an elevation of pH in the soiland contents of Ca 2+ and Mg 2+ in the watersheds P and C in relation to the watershed M. Due to deforestation and the establishment of agriculture and livestock, there was a decrease in the contents of soil organic matter in the watershed P and C, not altering the physical characteristics of the soilin the watershed P. The implementation of coffee plantation is causing a reduction in the soil quality of watershed C in comparison to the watershed P and M, therefore indicating a need to adequate soil management in this area.
broad spectrum, non-selective systemic herbicide, normally used for the control of annual and perennial weeds andcovercrops (Galli & Montezuma, 2005; Matallo et al., 2009). However, the effect of glyphosate on plant coverage is slow, taking a few days for those plants to die completely (Constantin & Oliveira Junior, 2005). Therefore, when herbicides are applied on the same day as that of soybean sowing, covercrops are still alive and standing. Consequently, there is initial shading insoybean seedlings, which harms their initial development (Santos et al., 2007). There have been reports of effects, such as yellowing, shading, reduced development, and reduction in crop yield (Constantin & Oliveira Júnior, 2005). According to Matallo et al. (2009), when glyphosate is applied near the crop sowing time, there may occur root exudation of herbicides from covercropstosoybean, especially if the roots from the covercrops treated with the herbicide are numerous and close to the roots of the crop.
Therefore, P and Mn contents of the grains were the only attributes used to define the management zones in the present study. Dalchiavon et al. (2013), Costa et al. (2014), and Bazzi et al. (2015) also used only those attributes that showed significant correlation with crop productivity. As for the positive correlation between the grain P content and grain productivity, since the phosphate fertilization was applied by broadcasting from 2004/05 until 2013/14, according to Barbosa et al. (2015), a deficiency in P absorption by the plants could be occurring, since it concentrates on the soil surface. As a result, the availability of P has decreased in the soilto the extent that the correlation between its soil content and grain content is significant. This indicates that for producing more grains, it is necessary to correct this low availability of P. In the case of the observed negative correlation
cropped with radish presented greater pH than the oats cover crop. These results may be because the residual material from oat straw is more difficult to decompose and tends to acidify the soil more because carbon dioxide is produced in the biological oxidation process of organic compounds, that react with water forming carbonic acid that disassociates releasing protons (H+) and can acidify the soil (Sousa et al. , 2007). On the other hand, the high pH of the soilin the radish cover crop in the second SCA was attributed to the chemical constitution of the species, that favors fast deposition of the biomass and alkalinization of the soil. Similar results were observed by Amaral et al. (2004), who reported that radish residues were more efficient insoil alkalinization than hairy vetch and oats residues. These authors attributed this fact to the pH neutralizing capacity andto increase in Ca 2+ and Mg 2+ in the soil due to the characteristics inherent to the residues of the species.
These results show that changes in acid phosphatase activity were associated with covercropsand a persistency of the plant effects. In a similar study, higher acid phosphatase activity was observed under oilseed radish and white lupine (Lupinus albus L.), which are both non-mycorrhizal, and this effect persisted under corn grown in the following season (Dalla Costa & Lovato, 2004). The persistence in this enzyme activity may be linked to its immobilization in complexes formed with mineral and humic colloids, which can become stable in the soil, depending on their molecular composition and chemical nature (Rao et al., 2000), and the soil organic matter, which plays an important role in providing substrate for P- mobilizing enzyme reactions from soil biota (Curci et al., 1997). The amount and quality of plant material incorporated into the soil are directly related to the nutritional conditions for the activity of microbial populations (Dick, 1992) and non-mycorrhizal crop residues may be associated with phosphatase activity and P mobilization in oilseed radish (Pavinato et al., 2008).