Cover crop diversity boosts soil health and yields in the Brazilian Cerrado

ABSTRACT

Sustainable intensification in tropical agriculture requires practices that simultaneously enhance soil health and crop yields. This study evaluated the effects of isolated and mixed cover crop species on soil physical quality and the performance of succession crops of soybean and corn in the Brazilian Cerrado. Fourteen cropping systems divided into a fallow treatment, isolated crops (corn, pearl millet, Brachiaria ruziziensis, Tamani grass, Coracana grass, Crotalaria spectabilis, Crotalaria ochroleuca, and Crotalaria breviflora), and five crop mixes were tested on clay-textured Rhodic Ferralsol under no-till. Assessments of soil physical properties were conducted in the field and laboratory to determine soil physical quality and soil quantification cover production. Subsequently, soybean (first season) and maize (second season) were sown in the experimental area to evaluate the residual effects of each treatment on the succeeding crops. Cover crops, especially mixes, increased dry matter production and soil cover (> 85%) and reduced surface temperature, thereby mitigating rapid residue decomposition. The mixes reduced penetration resistance in the 0–10-cm layer, increased hydraulic conductivity by up to 60% compared with fallow, and improved total porosity and bulk density. Soybean yields increased by up to 36% under mixed cropping, whereas C. spectabilis and pearl millet achieved the highest maize yields. Yield gains were strongly associated with lower soil compaction and cooler temperatures and improved infiltration. These results demonstrated that diversified cover crop systems deliver immediate and residual benefits to soil structure, water dynamics, and crop yield, offering a profitable and ecologically strategy for resilient agriculture in tropical systems.

Key words
Glycine max ; no-tillage system; profitability; soil physical quality

INTRODUCTION

Currently, most agricultural areas in Brazil involved in soybean cultivation are managed under a crop succession system, with soybean sown as the main crop during the summer growing season and corn as the second crop (Garbelini et al. 2020). Historically, the widespread adoption of the soybean-corn succession system by farmers has been attributed to the higher profitability of both crops at the time of commercialization, making the sustainability of the production environment a secondary consideration in crop planning (Braz et al. 2015).

Despite the short-term profitability of the soybean-corn succession system, its medium- to long-term continuation poses significant agronomic challenges. This system reduces microbial diversity in the soil, increases pest, disease, and weed pressure, and creates physical limitations in the soil that hinder plant development (Freddi et al. 2017). In contrast, in production environments in which crop diversification practices are implemented, benefits such as deeper soil profile exploration (through crops with distinct root systems), nutrient cycling, and mulch formation for no-tillage systems (NTS) have been observed (Renwick et al. 2021).

Intercropping of cover crops involves sowing two plant species of economic interest in the same area, which, when managed together, provides financial and agronomic benefits to farmers (Dzvene et al. 2023). Most farmers traditionally choose systems that include a single economically important crop (e.g., corn or sorghum). Although common, this approach often results in low biomass production and limited crop diversity, which can accelerate soil degradation and reduce the resilience of agroecosystems (Souza et al. 2025). In contrast, some Brazilian farmers have begun exploring the potential of alternative crops, such as Brachiaria and Crotalaria, and a smaller number have experimented with diverse cover crop mixes.

Cover crop mixes involve multiple species, typically without including a crop of direct economic interest, to harness the diverse benefits of grasses, legumes, and non-leguminous plants (Koudahe et al. 2022). In addition to the integrated benefits of cover crops, another objective of adopting mixtures is to ensure that at least one or a few species are established satisfactorily each year, producing sufficient biomass to improve the production environment, particularly soil properties.

In tropical agricultural systems of the Cerrado, maintaining soil cover and organic matter is particularly challenging due to rapid residue decomposition and limited biomass accumulation under seasonal water deficits (Ferreira et al. 2023b). In this context, the use of cover crop mixtures becomes essential, as combining species with different water use efficiencies and rooting patterns, and carbon-to-nitrogen (C/N) ratios enhances soil organic matter inputs and improves soil structure and moisture retention (Winck et al. 2014). Such diversification helps mitigate soil degradation processes, common in the Cerrado, where high temperatures and low residue persistence limit the sustainability of no-tillage systems.

In addition to increasing soil organic matter content, introducing cover crop mixtures into production systems can mitigate soil compaction. This is achieved through a greater diversity of species with varying root volumes and architectures that develop in the same region. Compaction results from a reduction in soil pore space due to external pressure, leading to decreased porosity and aeration, increased soil density, and physical restrictions on the root growth. These changes reduce water infiltration rates, oxygen availability to roots, access to water and nutrients, imposing physiological constraints on plant growth (Ferreira et al. 2020).

The continued use of crop succession systems has been shown to have deleterious effects on agricultural production environments, negatively affecting various chemical, physical, and biological soil properties. Incorporating cover crop mixtures into crop diversification systems in soybean-growing areas can enhance the soil environment and positively influence soybean development.

This study aimed to evaluate the effectiveness of various cover crops used (isolated or mixes) during off seasons in enhancing soil physical quality and agronomic performance of soybean and corn grown in succession within a production system in the Brazilian Cerrado. It was hypothesized that diversified cover crop mixtures would improve soil physical properties and subsequent crop performance more effectively than corn succession, single species cover crops, or fallow conditions.

MATERIAL AND METHODS

The experiment was set up in the experimental field of the Instituto Goiano de Agricultura, in the municipality of Montividiu, Goiás, Brazil, at 17°25’45.2” South latitude, 51°08’41.76” West longitude, and altitude of 863 m. The soil in the experimental area was classified as Rhodic Ferralsol, according to the World Reference Base (2015), or Latossolo Vermelho distrófico, according to the Brazilian classification system (Santos et al. 2018), with a clay loam texture and managed under a no-till system. The mineralogical composition of the soil mainly consists of iron and aluminum oxides (Marques et al. 2004). The experiment was conducted during the second harvest season (known as safrinha), and subsequent evaluations were carried out in the soybean crop season and the second corn crop, with the experimental period from April 2022 to August 2023.

The climate of the region is classified as Aw (Koppen-Geiger) tropical, with rainfall concentrated in the summer and a dry period during the winter. Precipitation data for the entire period during which the experiments were conducted are shown in Fig. 1.

Figure 1
Average temperature (T.) and observed precipitation during the field conduction period of the experiment conducted with cover crops from April 2022 to August 2023. Montividiu (GO), Brazil.

The experiment was conducted during the second crop season of 2022, followed by evaluations in the 2022/2023 soybean season, and the second crop season of 2023, with corn cultivated across the entire area to assess the residual effect of using cover crops. Prior to the implementation of the experiment, a chemical analysis of the soil in the 0–20-cm layer was performed to determine fertilizer recommendations. The observed values were pH (CaCl₂) 5.9; 0 cmol_c.dm^-3 of Al⁺³; 3.9 cmol_c.dm^-3 of Ca⁺²; 1 cmol_c.dm^-3 of Mg⁺²; 0.28 cmol_c.dm^-3 of K⁺; 18.58 mg.dm^-3 of available P (Mehlich-1); 2.61% organic carbon (Walkley-Black); and 495, 50, and 455 g.kg^-1 of sand, silt, and clay, respectively.

The experiment was conducted using a randomized complete block design with 14 treatments and four replications. The treatments consisted of isolated and mixed cultivation of cover crops. One treatment involved corn, representing the commercial standard in the region, whereas the other involved leaving the soil fallow (no plant species were cultivated). Table 1 lists all the treatments evaluated in the experiment.

Table 1
Treatments of isolated crops or mixes. Montividiu (GO), Brazil, 2022/2023.

Common name	Scientific name	Family
Fallow	-	-
Corn	Zea mays	P
Pearl millet	Pennisetum glaucum	P
Ruziziensis grass	Brachiaria ruziziensis	P
Tamani grass	Panicum maximum	P
Coracana grass	Eleusine coracana	P
Crotalaria-ochroleuca	Crotalaria ochroleuca	F
Crotalaria-spectabilis	Crotalaria spectabilis	F
Crotalaria-breviflora	Crotalaria breviflora	F
Mix 1: White oats + black oats + crotalaria breviflora + crotalaria ochroleuca	A. sativa + A. strigosa + C. breviflora + C. ochroleuca	P + P + F + F
Mix 2: White oats + black oats + pearl Millet + coracana grass	A. sativa + A. strigosa + P. glaucum + E. coracana	P + P + P + P
Mix 3: Crotalaria-breviflora + coracana grass	C. breviflora + E. coracana	F + P
Mix 4: Coracana grass + pearl millet	E. coracana + P. glaucum	P + P
Mix 5: Crotalaria-juncea + crotalaria-spectabilis + crotalaria-breviflora + crotalaria-ochroleuca + coracana grass	C. juncea + C. spectabilis + C. breviflora + C. ochroleuca + E. coracana	F + F + F + F + P

• P: Poaceae; F: Fabaceae.

The experimental units were 10 m wide and 5 m long, with a total gross area of 50 m². The cover crops were sown by broadcasting on April 11, 2022, which corresponded to the second season (safrinha). Each treatment was implemented according to the recommendations for each crop with respect to the number of seeds and the cultural practices for each system. To standardize the evaluation period for all treatments, soil sampling and soil cover evaluations were performed prior to soybean sowing.

The soil cover, dry matter, and soil temperature were analyzed. The soil cover was assessed in two samples for each plot using an iron frame measuring 0.5 × 0.5 m (0.25 m²), containing a line with 20 equidistant marked points. Coverage was quantified when these points coincided with vegetation. To determine the dry matter, the material within each iron frame was collected and placed in forced-air circulation oven at 65°C until it reached a constant weight. The dry mass was measured and adjusted to kg.ha^-1. Prior to material collection, the soil surface temperature was measured using a digital thermometer.

The saturated hydraulic conductivity was measured using the methodology described by Bagarello et al. (2004) as follows: for evaluation, polyvinyl chloride (PVC) cylinders (0.10 m in diameter and 0.25 m in height) were inserted into the soil to a depth of 5 cm. This technique involves the application of a small volume of water (V) to the surface of soil confined by a cylinder (with a cross-sectional area A) inserted into the ground and measuring the time from the application of water until the surface is no longer covered by water. The saturated hydraulic conductivity was calculated by Eq. 1:

(1) $$K_{sat}=\frac{\mathrm{\Delta }\theta }{(1-\mathrm{\Delta }\theta )t_{\mathrm{a}}}[\frac{\mathrm{D}}{\mathrm{\Delta }\theta }-\frac{\mathrm{D}+\left(\frac{1}{{\alpha }^{\ast }}\right)}{\partial \theta }\ln (1+\frac{(1-\mathrm{\Delta }\theta )\mathrm{D}}{\mathrm{\Delta }\theta (\mathrm{D}+\frac{1}{{\alpha }^{\ast }})})]$$

where: Δθ: the difference between the saturated soil water content (or total porosity) and the initial water content; D: V/A is the height of the water layer (m) at the beginning of the measurement; α: the ratio between Ksat and potential matric flow, which is defined by a constant value based on soil texture and structure.

The difference between the saturated and initial soil moisture contents was determined based on the volumetric moisture content. Based on the texture and structure of the soil, a value of = 12 m^-1 was used, as indicated by Bagarello et al. (2004).

Soil penetration resistance was evaluated using a Falker PLG 1020 penetrometer, measuring up to a depth of 40 cm two days after sufficient rainfall to moisten the soil profile near field capacity. In addition, soil moisture was determined in the 0–20-cm layer using a Falker HidroFarm HFM2030 soil moisture sensor.

Undisturbed soil samples were collected at depths of 0.0–0.1 m and 0.1–0.2 m, respectively. Small trenches (0.25 × 0.25 m) were opened, and two samples per plot were collected using stainless steel rings (diameter 0.05 m, height 0.05 m, and volume 10^-4 m³). The samples were wrapped in aluminum foil, carefully transported at 4°C, and saturated by capillary action for 48 h. The seedlings were then subjected to a matric potential of -6 kPa using a tension table. The total porosity was calculated as the difference between the mass of the saturated soil and that of the dry soil (Embrapa 2017), divided by the total volume of the sample, according to Eq. 2.

(2) $$\mathrm{TP}=(\mathrm{msu}-\mathrm{mss})/\mathrm{Vt}$$

where: TP: the total porosity (m³ m^-3); msu: the saturated soil mass (kg); mss: the dry soil mass (kg); Vt: the total sample volume, or the cylinder volume (m³).

The field capacity, or soil water content after equilibrium at a tension of 6 kPa as recommended by Severiano et al. (2011) for Oxisol in Cerrado biome, was determined as the volumetric soil water content after equilibrium at a tension of 6 kPa (Eq. 3), as follows:

(3) $$\mathrm{FC}=(\mathrm{msu}(-6\mathrm{kPa})-\mathrm{mss})/\mathrm{Vt}$$

where: FC = field capacity (m³ m^-3); msu (-6 kPa): the mass of moist soil equilibrated at a tension of 6 kPa (kg); mss: the mass of dry soil (kg); Vt: the cylinder volume (m³).

The soil aeration capacity was obtained by subtracting the field capacity from the water content at saturation. Soil bulk density was calculated as the ratio of the dry mass of the soil to the total volume. The penetration resistance was determined after equilibrium at 6 kPa tension using a dynamometer (Model FGV-200XY-SHIMPO) connected to a cone-shaped rod (30° angle) with a basal diameter of 4 mm, as described by Guedes Filho et al. (2014).

Soybean sowing was carried out on October 15, 2022, using the cultivar ST 700 I2X from BASF, with a row spacing of 0.45 m and a recommended seed density of 14 seeds per meter. This cultivar is characterized by early maturation (maturity group 7), indeterminate growth. Monoammonium phosphate (80 kg.ha^-1) was applied at sowing, and 120 kg.ha^-1 of potassium chloride (KCl) was applied when the crop was at the V3 stage.

During soybean crop development, all cultural practices were carried out according to recommendations. At physiological maturity, the final plant stand and grain yields were evaluated. Yield was achieved through mechanized harvesting using an Almaco model SP20 harvester along four central rows. This was subsequently adjusted to 13%.

In the second season of 2023, corn was sown to assess the persistence of cover crop effects and simulate the common practices adopted by farmers in the second season following cover crop cultivation. Corn was sown on February 27, 2023. The corn hybrid used was DKB255 PRO4 from Dekalb, at a density of five seeds per meter. During corn harvest, plant height and grain yield (corrected to 14% moisture content) were evaluated.

Data were analyzed using the SISVAR software (Ferreira 2011). Analysis of variance (ANOVA) was performed using the F-test, and significant effects were subsequently analyzed using the Scott-Knott’s test (p < 0.05). Principal component analysis (PCA) was performed to determine the correlations between the variables and crop responses using R software (version 4.4.6, Factorminer and Factorextra packages).

RESULTS AND DISCUSSION

Soil cover quality and soil physical parameters assessed in the field

Dry matter production was influenced by the cover crops (Fig. 2). All evaluated species showed greater biomass accumulation than that in the fallow system. However, the treatments with the highest dry matter production were corn, pearl millet, Mix 2, and Mix 4. Notably, both mixes were composed exclusively of grass species (Table 1), which are known for their physiological traits that influence biomass production and carbon/nitrogen (C/N) ratios, which are significant for ecosystem functioning and management (Ceballos-Núñez et al. 2025). The higher biomass observed in the corn treatment can also be attributed to its earlier sowing, which followed the recommended window for the crop and reflected local management practices. This management factor provided more favorable conditions for growth compared to the other treatments.

Figure 2
Dry matter production, soil cover, and soil temperature under different cover crops. Montividiu (GO), Brazil*.

It is important to highlight that in the context of production in the Brazilian Cerrado, high dry matter production is especially important because the region’s high temperatures accelerate the decomposition rate of plant residues. Furthermore, maintaining crop residues on the soil surface plays a key role in alleviating compaction caused by the traffic of agricultural machinery (Medeiros et al. 2024).

The cover crops demonstrated superior soil coverage compared to the fallow and corn treatments, with all cover crop treatments achieving over 85% coverage (Fig. 2). This enhanced coverage was attributed to the uniform distribution of plant residues on the soil surface, in contrast to corn straw, which tends to accumulate unevenly. The increased soil cover provided by the cover crops offers multiple benefits, including weed suppression and a significant reduction in soil temperature. Notably, crop mixes 2, 3, 4, and 5 achieved 100% soil cover, resulting in the lowest soil temperatures among all treatments. The moderated soil temperature likely created a more favorable microenvironment for the establishment of the subsequent soybean and corn crops, reducing thermal stress on seedlings and improving early growth conditions. The ability of cover crops to maintain low soil temperatures has far-reaching implications for subsequent crop development and overall soil health. Milder soil temperatures create a favorable environment for seed germination, root development, and initial crop growth. This is particularly crucial during the crop establishment phase, as it can mitigate the adverse effects of high temperatures that often hinder these processes. Additionally, maintaining cooler soil temperatures supports microbial activity and reduces water loss through evaporation, contributing to improved soil moisture retention and nutrient cycling (Li et al. 2022). These factors collectively enhance the growing conditions for subsequent crops, potentially leading to improved yields and more resilient agricultural systems (Newton and Guy 2020).

Soil penetration resistance at a depth of 0–10 cm showed that the cultivation of millet and Crotalaria species, as well as all mixes, presented the lowest values of penetration resistance (Fig. 3). Penetration resistance is a direct indicator of soil compaction, and high penetration resistance hinders root growth, water infiltration, and nutrient absorption. The other treatments (corn, fallow, Brachiaria ruziziensis, Tamani, and Coracana) did not differ from fallow and also showed higher values. This can be attributed to the delayed sowing of the cover crops, which occurred across all treatments and likely resulted in reduced plant and root system development. Consequently, the cover crops did not effectively contribute to lowering soil penetration resistance in the first year. Despite these differences, it is important to mention that all treatments in the 0–10-cm layer showed penetration resistance below the critical value for root development (2 MPa) (Tormena et al. 2007).

Figure 3
Soil penetration resistance in the 0–10-, 10–20-, and 20–40-cm layers under different cover crops. Montividiu (GO), Brazil*.

No significant differences in penetration resistance were observed among the evaluated treatments in the 10–20- and 20–40-cm layers (Fig. 3). This result may be related to the management history under a no-tillage system, which favors the maintenance of the soil physical structure at greater depths, reducing the occurrence of compacted layers and, consequently, variability among cropping systems. Another relevant factor is that substantial structural changes in subsurface layers generally require longer periods of cover crop adoption, especially for the combined action of fibrous and taproot systems, the effect of which on biological decompaction accumulates over the years.

This study examined soil moisture levels across various treatments, ranging from 18 to 27%. Treatments involving corn, fallow, millet, B. ruziziensis, Tamani, Crotalaria ochroleuca, and C. spectabilis demonstrated superior soil moisture retention, with values averaging between 24 and 27%. In contrast, the mixed treatments and C. ochroleuca exhibited lower moisture levels (19–23%). The lower soil moisture observed under the cover crop mixes was likely associated with greater water uptake and transpiration by the more vigorous and diverse vegetation, which maintained active growth and canopy cover for a longer period compared to single-species treatments or fallow. It is also important to note that the evaluation was conducted just before the onset of the rainy season and prior to soybean sowing, when soil moisture naturally tends to be lower. Therefore, although surface moisture appeared lower, the improved soil structure favored better water storage and availability in deeper layers, which benefited the subsequent soybean and corn crops during establishment and growth. This study highlights the importance of vegetative cover in soil moisture conservation, attributing its effectiveness to the formation of a dense, persistent layer that mitigates evaporation and enhances water infiltration (Souza et al. 2024).

Species with high biomass production and good soil coverage tend to perform better in maintaining soil moisture (Muhammad et al. 2022), which may explain the results observed for B. ruziziensis, millet, Tamani, and C. ochroleuca. The lower soil moisture values found in all the mixes were related to interspecific competition, lower combined adaptability of the species, and possibly greater water consumption during the off-season, which is characterized by the natural scarcity of water in the Brazilian Cerrado region. The reduced soil moisture in these treatments may have lessened the differences in penetration resistance between monocultures and mixes, as soil penetration resistance is significantly affected by moisture levels, with lower soil moisture typically increasing resistance because dry soils tend to be more compact and harder to penetrate (Yu et al. 2024). Finally, the poor performance of C. breviflora can be attributed to its limited biomass production and coverage capacity, which directly affect soil moisture conservation (Pacheco et al. 2017).

The highest saturated hydraulic conductivity (Ksat) values were obtained in the treatments composed of mixes Mix 1 to Mix 5 (Fig. 4), which did not differ from each other, indicating that species association favored soil water infiltration. Among the isolated crops, C. ochroleuca and C. spectabilis showed intermediate Ksat values, whereas C. breviflora performed similarly to the mixes, suggesting that its root architecture and/or its effect on soil structure contributed to higher hydraulic conductivity. In contrast, the lowest values were observed for corn, B. ruziziensis, and coracana. The observed pattern suggests that species diversity, a characteristic of the mixes, may have promoted greater soil bioporosity because of the combined action of different root systems, which enhance hydraulic conductivity (Souza et al. 2024). Additionally, the higher Ksat in the mixes may be associated with improved soil structure and reduced compaction, which are factors that enhance the water infiltration. These improvements in soil physical quality may have contributed to the better establishment and yield performance of the subsequent soybean and corn crops.

Figure 4
Soil moisture in the 0–20-cm layer and saturated hydraulic conductivity (Ksat) of the soil under different cover crops. Montividiu (GO), Brazil*.

Soybean and corn responses after cover crops

Soybean stand was not influenced by the different soil cover crops (Fig. 5). This suggests that the type of preceding crop does not negatively affect the initial establishment of soybean. Although there were variations in soil penetration resistance, they did not reach levels that would restrict crop development, and these differences were not sufficient to affect the initial soybean stand density. It is possible that the sowing conditions (such as adequate moisture and initial water distribution), as well as the fact that the experimental area has historically not had issues related to compaction, may have been favorable enough to ensure good emergence, regardless of the variability in soil resistance in the 0-10-cm layer.

Figure 5
Soybean stand, soybean yield, corn height and corn yield under different cover crops. Montividiu (GO), Brazil.

The lowest soybean yields were observed in the fallow and soybean/corn succession treatments, demonstrating that simplification of the no-till system negatively affects soil quality and the yield of the main crop—soybeans. Treatment with Mix 1, composed of white oats, black oats, millet, and coracana, increased soybean yield by 36% compared to that in the traditional soybean/corn succession system. Considering the price of soybeans in the Rio Verde region in 2023 (on May 2023, at R$ 117 per 60 kg sack), this translates to an increase in profitability of R$ 2,714,40 per hectare, showing that in addition to improving soil conservation, the gain in profitability for producers is significant.

The height of corn plants in the 2023 season after all cover crops and soybeans was significantly influenced by the preceding crops, being greater in the treatments with B. ruziziensis, coracana grass, C. spectabilis, and the diversified mixes, which provided better soil physical conditions (Fig. 5). In contrast, the lowest values were observed in the fallow treatment and successive corn cultivation in the second crop season, highlighting the negative effects of monoculture and simplification of the production system for soybean/corn succession, resulting in less vegetative cover, lower soil quality, and poorer crop development.

Corn yield in the off-season (Fig. 6), following the implementation of cover crops, was also influenced by the different cover crop species used. The fallow system resulted in the lowest yield, followed by the soybean–maize succession system. All cover crops outperformed the soybean–maize succession treatment in terms of maize productivity. The use of single cover crops, such as pearl millet and C. spectabilis, resulted in the highest maize yield. Pearl millet is known for its high potential to loosen soil and produce dry matter, which likely contributes to improved performance in production systems (Ferreira et al. 2023a).

Figure 6
Principal component analysis of cover crops related to soil physical properties, (a) agronomic characteristics and (b) cover crops.

Soil physical properties determined in the laboratory

The total porosity, soil bulk density, soil aeration capacity, field capacity, and penetration resistance at field capacity are presented in Table 2. Treatments with Tamani, C. ochroleuca, C. breviflora, and all the mixes showed the highest total porosity values, indicating improved soil structure. Total porosity is a key indicator of soil physical quality, as it directly influences aeration, water infiltration, and root growth (Reichert et al. 2009). The increase in total porosity observed in these treatments is likely associated with more vigorous and deeper root systems, which promote biopore formation and particle rearrangement. In the case of the cover crop mixtures, the combination of species with contrasting rooting patterns (fibrous and taproot systems) likely enhanced soil aggregation and pore continuity compared to monocultures. Additionally, the greater diversity in residue quality and decomposition rates in the mixes may have contributed to more stable soil organic matter and improved structural resilience. Together, these factors explain why the mixtures achieved better soil physical conditions than single species cover crops.

Table 2
Soil physical properties under different cover crops. Montividiu (GO), Brazil*.

Treatment	TP m3·m-3			BD Mg·m-3			AC m3·m-3			FC m3·m-3			PRfc MPa
	0–10-cm	10–20-cm	0–10-cm	10–20-cm	0–10-cm	10–20-cm	0–10-cm	10–20-cm	0–10-cm	10–20-cm
Corn	0.60 b	0.57 b		1.06 a	1.13 b		0.23	0.25		0.38	0.32 b		1.98 a	2.68 b
Fallow	0.58 b	0.56 b		1.08 b	1.11 b		0.24	0.23		0.34	0.33 b		2.30 b	3.08 b
Pearl Millet	0.57 b	0.59 b		1.14 b	1.06 a		0.23	0.26		0.35	0.34 b		2.93 b	1.50 a
B. ruziziensis	0.59 b	0.59 b		1.03 a	1.05 a		0.23	0.26		0.37	0.34 b		1.74 a	2.49 b
Tamani grass	0.61 a	0.62 a		1.04 a	1.03 a		0.24	0.29		0.38	0.33 b		1.66 a	1.57 a
Coracana grass	0.55 b	0.57 b		1.09 b	1.11 b		0.21	0.24		0.35	0.33 b		2.53 b	2.36 b
C. ochroleuca	0.61 a	0.61 a		1.11 b	1.10 b		0.23	0.24		0.38	0.36 b		2.50 b	2.06 a
C. spectablis	0.56 b	0.56 b		1.13 b	1.14 b		0.20	0.22		0.37	0.34 b		2.76 b	2.57 b
C. breviflora	0.61 a	0.65 a		1.07 b	1.01 a		0.21	0.24		0.41	0.41 a		2.10 a	1.77 a
Mix 1	0.63 a	0.64 a		1.10 b	1.02 a		0.21	0.27		0.43	0.37 a		1.99 a	1.12 a
Mix 2	0.61 a	0.54 b		1.09 b	1.14 b		0.23	0.21		0.38	0.34 b		2.21 a	3.22 b
Mix 3	0.64 a	0.66 a		1.02 a	1.02 a		0.21	0.28		0.43	0.38 a		1.03 a	1.30 a
Mix 4	0.62 a	0.61 a		1.05 a	1.14 b		0.26	0.28		0.37	0.32 b		2.06 a	2.85 b
Mix 5	0.64 a	0.63 a		1.00 a	1.05 a		0.24	0.23		0.40	0.41 a		2.52 b	1.55 a

• TP: total porosity; BD: soil bulk density; AC: aeration capacity; FC: field capacity; PRfc: penetration resistance at field capacity; *means followed by different letters in the column differ by the Scott-Knott’s test (p < 0.05); Mix 1: white oat (Avena sativa), black oat (A. strigosa), C. breviflora, and C. ochroleuca; Mix 2: white oat, black oat, pearl millet, and coracana grass; Mix 3: Crotalaria breviflora and coracana grass; Mix 4: coracana grass and pearl millet; Mix 5: C. juncea, C. spectabilis, C. breviflora, C. ochroleuca, and coracana grass.

Regarding soil bulk density at the 0–10-cm depth, the lowest values were observed in the treatments with corn, B. ruziziensis, Tamani, and in mixes 3, 4, and 5 (≤ 1.04 Mg m^-3), indicating less compaction in this layer. Reduced bulk density values were associated with fewer restrictions on root growth and improved oxygen diffusion in the soil (Hamza and Anderson 2005).

In the 10–20-cm layer, the lowest soil bulk density was recorded in treatments with pearl millet, B. ruziziensis, Tamani, C. breviflora, and mixes 1, 3, 4, and 5, indicating that the vigorous and contrasting root systems of grasses and legumes promoted structural improvements at depth. Conversely, the fallow, E. coracana, and C. spectabilis treatments exhibited higher bulk density and lower total porosity, reflecting physical degradation that restricts gas diffusion, water infiltration, and root development (Hamza and Anderson 2005, Blanco-Canqui et al. 2013). At the same depth, C. breviflora and mixes 1, 3, and 5 also showed higher field capacity, suggesting enhanced water retention associated with greater biopore formation and aggregate stability (Souza et al. 2024). These structural improvements, especially the combination of reduced compaction and increased water-holding capacity, likely contributed to the superior establishment and yield performance of the subsequent soybean and corn crops.

Soil penetration resistance is an important parameter for assessing compaction, which directly influences root growth and crop yield. PRfc is the penetration resistance measured at the field capacity. Values greater than 2.0 MPa are generally considered to limit root growth (Tormena et al. 2007). The values of penetration resistance at field capacity varied considerably between the treatments and depths (Table 2), reflecting the differences in the soil physical structure promoted by the cover crops. At the 0–10-cm depth, the lowest penetration resistance at field capacity values were observed in the diversified systems of mixes 1, 2, 3, and 4, as well as in the maize, B. ruziziensis, and Tamani treatments. These values indicated lower mechanical resistance to root penetration and greater ease of root growth and water infiltration. In general, these treatments also resulted in higher total porosity and lower soil bulk density, confirming the direct association between reduced compaction and lower PRfc.

In contrast, the highest PRfc values in the surface layer were observed in the fallow treatment and in crops treated with millet, C. spectabilis, coracana, and Mix 5, indicating more restrictive soil physical conditions. At a depth of 10–20 cm, the lowest values were recorded for mixes 1, 3, and 5, Tamani, and C. breviflora. These results showed that both individual cover crops with well-developed roots and diverse mixtures were able to promote improvements in the soil’s physical structure to a depth of 20 cm, contributing to a reduction in soil mechanical resistance. However, not all diversified systems were equally effective. This suggests that the composition of the mix, rather than diversity per se, is the determining factor for success.

In general, combinations that included species with contrasting root architectures and growth depths showed greater efficiency in reducing PRfc, particularly in deeper layers, due to enhanced biopore formation, higher biological activity, and improved soil aggregation promoted by complementary root interactions (Souza et al. 2024).

Interactions between soil physical properties and soybean and corn crops

PCA enabled the synthesis of the relationships between the soil’s physical properties and corn and soybean yields as a function of the different cover systems used (Fig. 6). The first two dimensions jointly explained 65.7% of the total data variability, with 43.8% in dimension 1 and 21.9% in dimension 2. In the projection of the variables, soybean yield showed an inverse correlation with soil resistance to penetration measured in the field (PRfc 0–10, PRfc 10–20), as well as with soil temperature, indicating that environments with higher compaction and higher temperatures are associated with lower yields. These findings corroborate earlier reports linking reduced yields in compacted soils to impaired root–soil–water interactions and increased evapotranspiration demand (Colombi and Keller 2019). Therefore, cover crop systems that reduce soil mechanical impedance and buffer soil thermal fluctuations, particularly those with high biomass production and uniform surface residue distribution, are more likely to create a favorable microenvironment for soybean development and yield maximization (Marshall et al. 2016).

PCA revealed system-level interactions that are not captured by individual analyses, highlighting how multiple soil properties act synergistically to influence crop performance. The distribution of treatments in the PCA showed clear patterns. Systems with Crotalaria ochroleuca, C. spectabilis, Mix 2, and Mix 4 clustered in the positive quadrant of dimension 1, which was directly associated with higher yields and better soil physical conditions, highlighting the effectiveness of these cover crops in improving the soil environment. In contrast, the treatments with corn, fallow, B. ruziziensis, and Tamani were in the negative quadrant of dimension 1 and were associated with greater soil resistance, higher bulk density, elevated temperature, and consequently, lower yield performance. Treatments with coracana, millet, Mix 1, Mix 3, and Mix 5 held an intermediate position, indicating that they promoted partial improvements in soil conditions, but not as significantly as the best treatments. This analysis provides valuable insights for farmers and agronomists in selecting optimal cover crop strategies for sustainable agriculture. Future research could focus on fine-tuning these cover crop combinations and exploring their long-term effects on soil health and crop yields across different agroecological zones.

Based on our results, the implications of cover crop use for agricultural management in the Brazilian Cerrado are significant. The adoption of cover crops, especially grasses and diversified mixes, has potential to improve agricultural yield and soil quality through greater biomass production, better soil coverage and reduced soil temperature, which are key factors in mitigating the rapid decomposition of residues and conserving moisture. In addition, improvements in soil physical properties, such as lower penetration resistance and higher hydraulic conductivity, reinforce the role of these species in reducing compaction and increasing water infiltration, thereby favoring the development of subsequent crops. The substantial increase in soybean and maize yield and profitability, compared to the traditional soybean–maize or fallow systems, demonstrated that diversification with cover crops is not only a conservation practice but also an economically viable strategy for farmers. These findings support the need for policies and technical recommendations to encourage the adoption of such practices to promote more resilient and sustainable agricultural systems in the region.

CONCLUSIONS

This study demonstrated that integrating cover crops, particularly diverse mixtures and grass-dominated systems, into production systems in the Brazilian Cerrado enhances both soil physical quality and subsequent crop performance. Cover crops significantly increased dry matter accumulation and soil cover and reduced surface temperatures, factors that mitigate rapid residue decomposition and conserve moisture under the region’s hot and dry conditions. Mixtures improved soybean productivity by up to 36%, whereas millet and C. spectabilis achieved the highest maize yields among single-species systems.

Diversified cover crops promoted lower penetration resistance, improved porosity, and increased hydraulic conductivity by an average of 60% compared with fallow, thereby facilitating better root growth, aeration, and water infiltration. Species combinations with contrasting root architectures were effective in improving soil structure at depths of 20 cm.

These results highlighted that crop use is an economically viable strategy for increasing system resilience, enhancing soil health, and boosting profitability in the Cerrado.

ACKNOWLEDGMENTS

To Instituto Goiano de Agricultura.

• How to cite:
  Rosa, V. C. S., Ferreira, C. J. B., Braz, G. B. P., Solino, A. J. S., Severiano, E. C., Paiva Filho, S. V. and Francischini, R. (2026). Cover crop diversity boosts soil health and yields in the Brazilian Cerrado. Bragantia, 85, e20250164. https://doi.org/10.1590/1678-4499.20250164
• FUNDING
  Fundação de Amparo à Pesquisa do Estado de Goiás
  Grant No.: 202310267001398
  Universidade de Rio Verde
  Chamada Interna 001/2023 Edital 002/2025
• DECLARATION OF USE OF ARTIFICIAL INTELLIGENCE TOOLS
  The English language was revised using the Paperpal program.

DATA AVAILABILITY STATEMENT

The data that support the findings of this study are available on request from the corresponding author.

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Edited by

• Section Editor:
  Osvaldo Guedes Filho https://orcid.org/0000-0001-8550-8505

Publication Dates

• Publication in this collection
  16 Feb 2026
• Date of issue
  2026

History

• Received
  15 Aug 2025
• Accepted
  05 Dec 2025