Can Soil Cover Affect the Performance, Yield, and Quality of Creeping Fresh Market Tomato Hybrids?

Abstract

Soil cover is a major factor in the cultivation of creeping tomatoes, especially for in natura consumption. This study aimed to determine the combination of a suitable tomato hybrid and soil cover, resulting in superior production performance and quality attributes of tomato fruits. Tomato hybrids (Fascínio and Thaíse) were cultivated on five soil cover types (uncovered soil, plastic mulch, sorghum, Sudan grass, and pearl millet). The data were submitted to a principal component analysis (PCA), considering all the variables, through Biplot graphical analysis. A Pearson correlation analysis was performed at the 5% significance level. For biomass production, pearl millet and Sudan grass were distinguished from the other soil covers, showing lower decomposition rates and, consequently, longer half-lives. Covering with plastic mulch provided higher total (111 t ha⁻¹) and commercial (74.4 t ha⁻¹) yields, regardless of the analyzed hybrid. According to the PCA, soil cover management influences the production and quality of tomato fruits, except for chemical and post-harvest characteristics, and maintains ideal levels for commercialization for all treatments. The Fascínio hybrid presented better production attributes, higher total and commercial fruit production per plant as well as fruits with larger sizes, especially when grown in plastic mulch cover. The Fascínio hybrid also presented fruits with higher levels of bioactive compounds (lycopene and β-carotene).

1. Introduction

Tomato (Solanum lycopersicum L.), the most consumed vegetable fruit, is highly important in world agriculture [1]. The industry and the final consumer demand that tomatoes have a good appearance and thus add value, which is related to the quality aspects of the fruits. With the potential for the expansion of the culture and demanding consumer market, there is a growing search for technological and alternative management methods to increase production and improve the physical, chemical, and biochemical qualities of tomatoes by combining soil conservation and sustainability in agriculture [2,3,4].

Soil coverage has several benefits to the production process, improving the quality of tomato fruits and soil, such as weed control, the reduction of water loss by evaporation, assistance in irrigation management, ease of harvesting, and marketing [5,6,7,8]. Furthermore, owing to the reduction in direct contact of the fruits with the soil, the soil cover promotes better quality plants and fruits; thus, they are harvested cleanly and with better quality and health, especially in creeping tomato hybrids [9].

Different soil cover types affect the growth and vigor of tomato plants, fruit maturity, and total production. This technique retains higher soil moisture, with higher microbial activity and soil organic nitrogen mineralization, increasing the availability of nutrients for the plants. In addition, it reduces the rate of rotting fruits with the presence of straw, especially when using coverings with pearl millet and sorghum biomass and plastic mulch (polyethylene film), resulting in increased yields of various crops [8,10,11].

Tomatoes are rich in carotenoids, precursors of vitamin A, and antioxidants, with fundamental functions in nutrition and the prevention of cancer and heart diseases [12]. Among other factors, the levels of carotenoids in tomatoes depend on geographical characteristics, seasonal factors, hybrids, and management [13].

Companies have recently developed tomato hybrids with determinate growth habits focused on the fresh market, aiming to reduce labor, production costs, and pesticide application, as they are early-cycle cultivars with fruit maturation at a defined and more uniform time, obtaining advantages in harvesting and marketing. We are thereby facing a technological advance for tomato culture, aiming to intensify production on a large scale, requiring further research on the cultivar adaptation to the conditions of each cultivation system. Therefore, if productivity and fruit quality of determinate growth habit tomatoes with a trailing training system are similar to the traditional method (using cultivars with indeterminate growth habits), one can benefit from the advantages described here. Thus, more studies are needed on their adaptation to the growing conditions of each region.

Owing to the beneficial effects of bioactive compounds, identifying hybrids and environments that increase the production of these phytochemicals in tomato fruits is necessary. Therefore, there is a need to study the relationship between tomato hybrids and soil cover in fruit production and quality to support decision-making aimed at producing fruits of better physical and nutritional quality. Therefore, this study aimed to compare the effects of creeping fresh market tomato hybrids on different soil covers regarding yield and fruit quality attributes.

2. Materials and Methods

2.1. General Description

The study was conducted in the winter period of 2019 (July to November) in Tangará da Serra, Mato Grosso, Brazil (latitude 14°39′00″ S, longitude 57°25′54″ W, and at an altitude of 440 m). The climate of the area is megathermal or tropical with a dry winter (Aw) according to the Köppen climate classification [14], with an annual average air temperature of 24.4 °C and an average annual precipitation of 1830 mm (the weather data are presented in Supplementary Material, Figure S1).

Planting was performed in soil, dystrophic Red Latosol (Oxisol), with the following characteristics at 0.00–20.0 cm depth: sand = 287 g kg⁻¹; silt = 149 g kg⁻¹; clay = 564 g kg⁻¹; pH = 5.80 (water); organic matter (OM) = 38.8 g dm⁻³; P = 1.00 mg dm⁻³; K = 0.240 cmol_c dm⁻³; Ca = 1.50 cmol_c dm⁻³; Mg = 0.90 cmol_c dm⁻³; Al = 0.00 cmol_c dm⁻³; H = 6.00 cmol_c dm⁻³; cation exchange capacity (CEC) = 8.60 cmol_c dm⁻³; percent base saturation (BS) = 30.0%; B = 0.30 mg dm⁻³; and Zn = 3.10 mg dm⁻³ (AGROSOLO Agronomic Analysis Clinic, Brazil) [15].

Chemical analysis of the experimental area soil was carried out after tomato cultivation and after the final harvest according to the soil covers studied, aiming to investigate the effects of different soil covers on nutrient levels present in the soil (

Table 1. Chemical analysis of dystrophic Red Latosol (Oxisol) in the layer from 0.00 to 0.20 m after tomato harvest at the end of the creeping fresh market tomato hybrids crop cycle, grown under different soil covers in Tangará da Serra, Mato Grosso, Brazil, 2019.

Sample (Soil Cover)	Depth	pH	P Mehlich	K	Ca + Mg	Ca	Mg	Al	H	H + Al	OM
	cm	H2O	mg dm−3	cmolc dm−3							g dm−3
Uncovered soil	0–20	5.00	11.0	0.280	2.30	1.60	0.70	0.20	8.00	8.20	24.6
Plastic mulching	0–20	4.80	54.0	0.410	1.80	1.30	0.80	0.20	9.70	9.90	24.3
Sorghum	0–20	5.50	7.00	0.230	3.50	2.50	1.10	0.00	6.60	6.60	25.5
Sudan grass	0–20	5.40	3.00	0.300	3.20	2.00	1.20	0.00	6.90	6.90	28.8
Pearl millet	0–20	5.10	29.0	0.250	3.10	2.10	0.90	0.10	8.10	8.20	24.9

Source: AGROSOLO Agronomic Analysis Clinic, Nova Mutum, Mato Grosso, Brazil (December 2019). Teixeira et al. [15]. OM = organic matter.

).

2.2. Treatments and Experimental Design

Two creeping fresh market tomato hybrids with determinate growth habits were studied: a salad-type (Thaíse Hybrid) and an Italian-type (Fascínio Hybrid), both from Feltrin Seeds (Feltrin Sementes, Brazil) (the characteristics of the hybrids are presented in Supplementary Material, Table S1), grown on five soil coverings: (a) uncovered soil (conventional planting), (b) plastic mulching (double-sided black and white 25-micron polyethylene film), (c) sorghum (Sorghum bicolor (L.) Moench) (cv. JB1330); (d) Sudan grass ((Sorghum sudanense (Piper) Stapf) (cv. ANsf 306), and (e) Pearl millet (Pennisetum glaucum (L.) R.Br.) (cv. ANm 17) (the characteristics of the covers crops are presented in Supplementary Material, Table S2). The experimental design was a randomized block design (RBD) with four replicates organized in a 2 × 5 factorial scheme (two tomato hybrids and five soil coverings) (the layout is presented in Supplementary Material, Figures S2 and S3). Each experimental plot comprised four beds, with dimensions of 2.50 × 1.20 m; thus, each treatment comprised 16 beds of 3.00 m² each.

2.3. Soil Preparation and Implantation of Soil Cover Species

The soil in the experimental area was prepared 30 days prior to the experiment. First, the site was mowed, followed by liming of the soil (raising the base saturation to 70%) using dolomitic limestone with 100% RPTN, followed by the incorporation of a plow and leveling harrow. The beds were sequentially surveyed using a rotary hoe.

The sowing of cover crops was carried out on the beds, with a spacing of 0.30 m between rows, using 20.0 kg ha⁻¹ (250,000 plants ha⁻¹) of pearl millet seeds, 15.0 kg ha⁻¹ (180,000 plants ha⁻¹) of sorghum seeds, and 25.0 kg ha⁻¹ (200,000 plants ha⁻¹) of Sudan grass seeds. At the beginning of cover crop flowering (60 days after sowing), they were cut in the plots, leaving crop residues (fresh straw) on the surface of the beds, which later became dry plant biomass. On the day of cutting, the initial fresh biomass was 7.85 t ha⁻¹ for sorghum, 7.80 t ha⁻¹ for Sudan grass, and 9.10 t ha⁻¹ for pearl millet.

2.4. Implantation and Management of Tomato Plants

The tomato seedlings of all treatments were produced under protected cultivation (greenhouse) covered with polyethylene plastic film in trays of 128 cells. These tomato seedlings were produced in the same soil (commercial substrate) before being transplanted to the soil where soil cover was applied. Tomato seedlings were transplanted when the plants had three definitive leaves (22 days after emergence—1 August 2019). The furrow where the seedlings were transplanted was made 0.15 m from the side edge of the bed, spaced 1.20 m between rows. The spacing between plants was 0.50 m, with a total population of 13,333 plants ha⁻¹. During plant growth, the plants were directed such that they were on the cover of the bed.

Base-dressing (pre-plant) fertilizers, urea (30.0 kg ha⁻¹), potassium chloride (60.0 kg ha⁻¹), and simple superphosphate (1200 kg ha⁻¹) were applied and incorporated to a depth of approximately 150 mm by rotary cultivation. Moreover, fertigation at different growth stages was applied to all plants at doses of 270 kg ha⁻¹ calcium nitrate, 540 kg ha⁻¹ potassium chloride, 2.00 kg ha⁻¹ ammonium sulfate, 5.00 kg ha⁻¹ potassium nitrate, 2.00 kg ha⁻¹ boric acid, and 4.00 g ha⁻¹ zinc sulfate per hectare (total amount of each nutrient applied during the cultivation period), using a drip irrigation system on six occasions at approximately 1-week intervals, up to the end of the scheduled irrigation period [16].

Irrigation was carried out using a drip system, with the drippers spaced at 0.30 m and a working pressure of 10 m.c.a., with a daily irrigation shift (the layout of the drip irrigation system is presented in Supplementary Material, Figure S3). As a result, the Christiansen Uniformity Coefficient (CUC) for the irrigation system averaged 86%.

2.5. Evaluation of Tomato Variables Grown in Different Soil Covers

The experiment was evaluated in relation to the cultivation of two hybrids of creeping fresh market tomatoes with determined growth habits (Thaíse and Fascínio) cultivated in different soil covers. The experiment evaluated the chemical, physical, and biochemical aspects, production components, yield, and post-harvest shelf life of tomatoes. In addition, for cover crops (pearl millet, sorghum, and Sudan grass), evaluations were made of the dry biomass of aerial parts, decomposition rate, the half-life of cover crops, and spontaneous vegetation (weeds) in treatments with uncovered soil.

2.5.1. Determination of Dry Biomass, Decomposition Rate, and Half-Life Time of Cover Crops

The dry biomass of the aerial parts of cover crops was determined at the beginning of flowering. Four samples of 0.25 m² per plot were randomly collected. The collected material was dried in an oven with forced air circulation at 65 °C until a constant mass was obtained [17].

Dry plant material (20.0 g) from each sample obtained in the previous analysis was placed in decomposition bags (litter bags) to evaluate the decomposition rate. These were made with white shading mesh (5 mm) measuring 0.20 × 0.20 m. Four decomposition bags were arranged on the surface of each plot so that at 25, 50, 75, and 100 days after distribution, a bag was collected for evaluation. The decomposition rate (k) in g g⁻¹ of plant residue was determined according to Thomas and Asakawa [18], using Equation (1):

$${\mathrm{X}}_{\mathrm{t}}{=\mathrm{X}}_{\mathrm{o}}{\mathrm{e}}^{-\mathrm{kt}}$$

(1)

X is the amount of dry matter remaining after period t, days;

X_o is the initial amount of dry matter or nutrients;

k is the biomass decomposition rate constant.

Thus, with the value of k, the half-life (T_1/2) of plant residues in days was calculated using the methodology of Paul and Clark [19], which expresses the period necessary for the decomposition of half of the residues or the release of half of the nutrients contained in them, according to Equation (2):

$${\mathrm{T}}_{1/2}=\frac{0.693}{\mathrm{k}}$$

(2)

T_1/2 is the half-life of plant residues, days;

k is the biomass decomposition rate constant.

2.5.2. Tomato Production Components

The tomato fruits were harvested when they reached a ripe red color (ripe fruit at ripening stage 6—more than 90% intense red color) [20], with harvesting starting 70 days after transplanting (DAT) and ending at 100 DAT, counted, and their mass was measured on a semi-analytical scale. Their dimensions (diameter and length in mm) were determined using a digital caliper, and the size of the fruits was classified. In addition, the following were determined: total and commercial yields (commercial standard corresponds to the total number of fruits minus those with damage, all extra) in t ha^−1, non-commercial yield, commercial yield according to fruit size (small, medium, and large) in t ha⁻¹, fruit production per commercial plant and commercial production of small, medium and large fruits in kg plant⁻¹, number of fruits per commercial plant, and average commercial fruit weight in kg [21,22].

2.5.3. Physicochemical and Biochemical Analyzes of Tomato Fruits

Hydrogen Potential (pH), Titratable Acidity, Soluble Solids, and Maturation Index

The hydrogen potential (pH) was determined by directly reading the homogenized pulp solution using a digital pH meter (portable Q400HM model, QUIMIS, Diadema, Brazil) [23]. The titratable acidity (TA) was determined in aqueous extract using 5 g of processed tomato, homogenized in 50.0 mL of distilled water, and titrated in NaOH 0.1 N. The results were expressed as the percentage of citric acid per 100 g of fresh sample [23]. The soluble solid (SS) content of the samples was analyzed using a digital refractometer (model ITREFD 45/65/92, Instrutemp, São Paulo, Brazil), and the results were expressed in °Brix [23]. The maturation index (RATIO) was calculated as the ratio of SS to TA.

Lycopene and β-Carotene Content

Lycopene and β-carotene contents in tomato fruits were quantified according to Nagata and Yamashita [24]. One gram of processed tomatoes was homogenized in 10.0 mL of acetone:hexane (4:6 v/v) for 1 min in tubes protected from exposure to direct light. The resulting solution was analyzed in a UV-Vis spectrophotometer (Thermo Scientific Evolution 160 UV-VIS, American Laboratory Trading, East Lyme, CT, USA) after centrifugation at 4000 rpm for 10 min at 4 °C. The absorbance was determined at 663, 645, 505, and 453 nm, and the concentration of lycopene and β-carotene was expressed in µg 100 g⁻¹ of fresh tomato weight (Equations (3)–(5)).

$$\mathrm{Lycopene}=-0.046{\mathrm{A}}_{663}+0.204{\mathrm{A}}_{645}+0.372{\mathrm{A}}_{505}-0.081{\mathrm{A}}_{453}$$

(3)

$$\mathsf{\beta }\text{-}\mathrm{Carotene}=0.216{\mathrm{A}}_{663}-1.22{\mathrm{A}}_{645}-0.304{\mathrm{A}505\mathrm{A}}_{505}+0.452{\mathrm{A}}_{453}$$

(4)

$$\mathrm{Lycopene}\mathrm{or}\mathsf{\beta }\text{-}\mathrm{carotene}=\frac{\left[\left(\mathrm{A}\frac{\mathrm{mg}}{100}\mathrm{mL}\right) \text{×} \mathrm{mL}\mathrm{acetone}\text{:}\mathrm{hexane}\right]}{\mathrm{sample}\mathrm{weight}}$$

(5)

Lycopene is the content of this carotenoid in tomato fruits, µg 100 g⁻¹;

β-carotene is the content of this carotenoid in tomato fruits, µg 100 g⁻¹;

A_x is the absorbance at wavelength x.

2.5.4. Post-Harvest Shelf-Life Analysis of Tomato Fruits

The post-harvest shelf life of tomato fruits was determined using 25 mature fruits of the commercial standard of each hybrid cultivated in different soil covers, harvested at stage 6 (90% red color), 70 days after transplanting (DAT) at the beginning of the tomato harvest. The fruits were cleaned with running water and 1% sodium hypochlorite and placed in expanded polystyrene trays at room temperature (16.0 ± 2.00 °C and relative humidity of 80 ± 2%). The percentage of post-harvest mass loss (%) was performed every three days for twenty-seven days, the maximum period in which the fruits were suitable for consumption, and was determined by the difference between the initial mass and the mass obtained in each evaluation.

2.6. Statistical Analysis

The data were subjected to homoscedasticity of variances by the Shapiro-Wilk test and analysis of variance (ANOVA), when significant, submitted to the Scott-Knott test (p ≤ 0.05), using the STATISTICA software [25]. A Pearson correlation analysis was carried out using the t-test at a 5% significance level to relate the degree of dependence between the variables of the tomatoes grown in different soil covers. The data were also subjected to multivariate statistical analysis (principal component analysis [PCA]) using the XLSTAT software, version 2020 [26].

3. Results and Discussion

3.1. Soil Cover and Fruit Yield

There was no difference in the stages of phenological development of tomato hybrids (Fascínio and Thaíse) and in tomatoes depending on soil cover. The total cycle, from sowing to the end of the harvest, was 130 days (the phenological stages are presented in Supplementary Material, Figure S4). The vegetative phase from sowing to the emission of the first inflorescence lasted 46 days, of which 22 days was the duration of the seedling production phase from sowing to transplanting, and the vegetative stage after transplanting corresponded to 24 days. The cultivation cycle was 109 days, considering the period between transplantation and final harvest.

The period between flowering and the end of fruit-filling lasted for 34 days, after which the fruits took 20 days to fully mature. The fruits were harvested as soon as they reached full maturation, and the period from the first to the last harvest was 30 days. Most determinate habit tomato hybrids have a cycle of up to 125 days, however, this depends on the climatic conditions, where high temperatures accelerate the cycle [27].

Regarding soil cover, the total plant dry biomass produced, decomposition rate (k), and half-life (T_1/2) were observed in each treatment except for plastic mulching (

Table 2. Dry biomass of aerial part (DBAP), decomposition rate (k) and half-life time (T_1/2) of dry mass of plant residues from soil covers used in this experiment. Tangará da Serra, Mato Grosso, Brazil, 2019.

Soil Covers	DBAP (t ha−1)	k (g g−1)	Half-Life Time (T1/2) (Days)
Spontaneous vegetation (Uncovered soil)	4.65 ± 2.30 b	0.023 ± 0.003 a	31.0 ± 3.40 b
Sorghum	7.85 ± 0.70 a	0.020 ± 0.001 b	34.4 ± 1.40 b
Sudan grass	7.80 ± 0.90 a	0.017 ± 0.002 c	42.4 ± 3.90 a
Pearl millet	9.10 ± 0.90 a	0.016 ± 0.002 c	44.9 ± 4.60 a
F values	1.25 *	0.057 *	0.028 *
C.V. (%)	20.3	8.72	7.78

Means followed by the same lowercase letter in the columns do not differ among themselves statistically, according to the Scott-Knott test at 5%. Analysis of variance = * p-value ≤ 0.05 significant at 5% probability. All data are expressed as the mean ± standard error. C.V., coefficient of variation.

).

In terms of biomass production, pearl millet, Sudan grass, and sorghum produced the driest material in the soil, followed by spontaneous vegetation (weeds). The difference between pearl millet and spontaneous vegetation was 4.45 t ha⁻¹, corresponding to 48.9% lower soil cover. Furthermore, pearl millet and Sudan grass had the lowest decomposition rates and, consequently, the longest half-lives (Table 2). These results indicate the importance of soil cover crops in relation to spontaneous vegetation, which, in addition to providing greater production of dry biomass, has a longer half-life; that is, longer coverage with straw in the soil.

The use of mulch is considered beneficial for conserving soil moisture, eliminating weeds, and subsequently increasing the nutrient supply to the soil through plant decomposition [8,11,28,29]. In tomatoes, cover crops (e.g., pearl millet and sunn hemp) improve fruit quality and suppress weed growth during plant cultivation [28]. Mulching with organic material (rice straw, grass clippings, and sawdust) is an accepted practice for many agricultural crops owing to its ability to conserve soil moisture and temperature, control a wide variety of weeds, prevent disease in crops, and improve soil fertility by increasing the organic matter content, in addition to being a repellent of different harmful insects [29].

Different types of soil cover materials are used for effective plant growth, better weed control, and healthy soil conditions [29,30]. Among the various soil cover materials, plastic mulch, velvet bean (Mucuna deeringiana [Bort] Merr.), sunn hemp (Crotalaria junceae L.), and pearl millet (Pennisetum americanum Leeke) are commonly used in tomatoes plantings [28,29]. When there are different cover crops in the tomato crop, pearl millet is the best cover crop for biomass production, in addition to suppressing weed establishment [28].

Although cover crops are efficient at controlling weeds, coverage with plastic mulch (black plastic mulch) offers the best control without compromising crop yield [29,31,32]. Black plastic mulch is a good absorber and radiator of heat that reduces the penetration of light into the soil surface and promotes less water evaporation. In evaluating the performance of Rosa centifolia in response to soil cover type, plastic mulch cover was the most efficient in controlling weeds, with maximum conservation of soil moisture and a greater number of branches per plant, flowers, petals, leaves, and root length [31]. In tomatoes, covering with black plastic (50.0 µ) proved to be highly effective in weed suppression and increased the tomato crop yield [29]. Therefore, the black plastic cover should be encouraged as a management strategy to suppress weeds [29,33].

For the two tomato hybrids tested, the highest average total yield (TY) (111 t ha⁻¹) was obtained using the treatment with plastic mulch soil cover, which differed from the other treatments (

Table 3. Effect of tomato hybrid and soil cover on total yield (TY), commercial yield (CY), non-commercial yield (NCY), total production per plant (TP), commercial production per plant (CP), number of medium size fruits per plant (MF) and total number of fruits per plant (TNFP) of creeping fresh market tomato hybrids. Tangará da Serra, Mato Grosso, Brazil, 2019.

Source of Variation	Yield			Fruit Production Per Plant		Number of Fruits
	TY	CY	NCY	TP	CP	MF	TNFP
	(t ha−1)			(Kg Plant−1)		(Unit Plant−1)
Hybrid
Fascínio	95.8 ± 6.80	65.0 ± 8.50	30.8 ± 3.00 a	7.18 ± 0.60	4.87 ± 0.60	24.8 ± 3.50 a	77.9 ± 8.90 a
Thaíse	94.8 ± 15.9	67.0 ± 12.7	27.9 ± 3.30 b	7.11 ± 1.20	5.02 ± 1.00	17.6 ± 5.70 b	65.6 ± 11.8 b
Soil cover
Uncovered soil	92.8 ± 13.7 b	62.9 ± 12.7 b	29.9 ± 3.70 b	6.95 ± 1.00 b	4.71 ± 0.80 b	21.8 ± 5.40 a	68.7 ± 7.60 b
Plastic mulching	111 ± 19.7 a	74.4 ± 17.3 a	36.1 ± 3.90 a	8.29 ± 1.50 a	5.58 ± 1.20 a	23.3 ± 5.50 a	84.8 ± 12.7 a
Sorghum	92.5 ± 14.0 b	67.7 ± 9.90 b	24.8 ± 5.00 b	6.93 ± 1.00 b	5.07 ± 0.70 b	22.5 ± 5.90 a	67.1 ± 11.8 b
Sudan grass	88.4 ± 13.6 b	59.3 ± 12.1 b	29.1 ± 3.50 b	6.63 ± 1.00 b	4.45 ± 0.80 b	17.3 ± 5.90 b	70.0 ± 9.60 b
Pearl millet	92.3 ± 8.1 b	65.6 ± 9.40 b	26.7 ± 2.40 b	6.92 ± 0.60 b	4.92 ± 0.70 b	23.3 ± 4.90 a	68.0 ± 8.20 b
F values
Hybrid	0.06 ns	0.41 ns	5.28 *	0.060 ns	0.410 ns	34.8 *	26.9 *
Soil cover	4.37 *	2.75 *	9.26 *	4.37 *	2.75 *	2.90 *	7.76 *
Hybrid × Soil cover	0.34 ns	0.48 ns	0.16 ns	0.34 ns	0.48 ns	0.36 ns	0.42 ns
C.V. (%)	12.4	14.7	13.6	12.4	14.7	18.1	10.5

Means followed by the same lowercase letter in the columns do not differ among themselves statistically, according to the Scott-Knott test at 5%. Analysis of variance = * p-value ≤ 0.05 significant at 5% probability; ^ns not significant, by F-test. All data are expressed as the mean ± standard error. C.V., coefficient of variation.

). As observed for the total yield, in the commercial yield (CY), an isolated effect was also observed for the soil cover factor, with the highest yield provided by the treatment with plastic mulching in the two hybrids, with averages of 65.0 and 67.0 t ha⁻¹ for the hybrids Fascínio and Thaíse, respectively, with a production of 3.31 and 6.15% higher than the average of the treatment with uncovered soil (62.9 t ha⁻¹) (Table 3).

An isolated effect was verified for the hybrid tomato and soil cover factors regarding the variable non-commercial yield (NCY) (Table 3). The Fascínio hybrid had an average of 30.8 t ha⁻¹, which was 9.43% higher than that of the Thaíse hybrid (27.9 t ha⁻¹). As for the soil coverings, the highest NCY average (36.1 t ha⁻¹) was obtained for the treatment with plastic mulching, with an increase of 17.1% in relation to the treatment with uncovered soil, with an average NCY of 29.9 t ha⁻¹. For the production of fruits per plant (kg plant⁻¹), an isolated effect was observed for soil coverings, where the covering with plastic mulching obtained the highest total production per plant (TP) and commercial production per plant (CP), with averages of 8.29 and 5.28 kg plant⁻¹, respectively, in relation to other soil covers (Table 3).

Regardless of the cover crop used, plastic mulch was the best cover for improving tomato fruit yield and quality. As observed in this study, an increase in commercial yield owing to plastic mulching has also been reported in other studies [34,35]. The most frequently used plastic mulch for vegetable growth is a black polyethylene film, which has very good properties and a relatively low price. During cultivation with a black polyethylene film, the initial production of tomato fruits was 24% higher than that of fruits not covered with mulch [36].

The color of the plastic soil cover (plastic mulch) also influences tomato yield, depending on the growing region. For example, the fruit yield of tomatoes grown in black or silver-black polyethylene film increased by 50 and 65%, respectively, compared to that of tomatoes grown in uncovered soil [37]. However, studies evaluating sowing dates and plastic covering in black and white colors have shown that tomato plants grown under white covering have a yield increase of up to 40% compared to soil covered with black plastic [38].

Regarding the number of medium-sized fruits per plant (MF), an isolated effect was observed for hybrids and soil cover (Table 3). Among tomato hybrids, Fascínio presented the highest number of fruits of this size, with an increase of 28.8% in relation to the Thaíse hybrid; among soil coverings, the treatment without covering, plastic mulching, sorghum, and pearl millet differed from Sudan grass.

When we considered the total number of fruits per plant (TNFP), there were isolated effects for hybrids and soil cover (Table 3), such that the treatment with plastic mulching presented the highest number of fruits per plant, which differed from the other treatments. Among the hybrids, Fascínio had an average of 77.9 fruits, compared to 65.6 for the Thaíse hybrid, a difference of 15.8%. When evaluating the effect of soil coverage, plastic mulching differed from the other treatments, with an average of 88.8 fruits per plant.

Tomato yield in response to different soil coverings (jute, plastic mulching, and straw cover) and irrigation depths in the two years of cultivation was higher in the plastic mulching treatment, followed by cover with straw, jute, and uncovered soil [35]. The number of fruits per plant was 18.8% (64 and 52 fruits per plant) and 20.3% (64 and 51 fruits per plant) higher for plastic mulching than for non-covered mulching in 2016/2017 and 2017/2018, respectively [35]. Kundu et al. [35] presented data on coverage with straw compared to the control, and the increments in the number of fruits were, respectively, 10.34% (58 and 52 fruits per plant) and 17.7% (82 and 51 fruits per plant), for the first and second year evaluated. The yield was 60.3 and 58.7 t ha⁻¹ for the first and second years, with 35.8 and 38.7% increases when not covered. For the straw cover treatment, the increments in relation to the control treatment were 23.8 and 30.5%, with average yields of 50.8 and 51.8 t ha⁻¹ for 2016/2017 and 2017/2018, respectively [35].

Considering the number of fruits per plant by size, the number of small fruits (SF) and large fruits (LF) had only an isolated effect on the hybrids (

Table 4. Effect of tomato hybrid and soil cover on peduncle thickness (PEDUNC); number of small fruits per plant (SF), number of large fruits per plant (LF); total number of commercial fruits per plant (TNCF); production of small size fruits per plant (PSF), production of large size fruits per plant (PLF), total yield of small-sized fruits (TYS) and total yield of large-sized fruits (TYL) of creeping fresh market tomato hybrids. Tangará da Serra, Mato Grosso, Brazil, 2019.

Source of Variation	Physical Variable	Number of Fruits			Fruit Production Per Plant		Total Fruit Production
	PEDUNC	SF	LF	TNCF	PSF	PLF	TYS	TYL
	(mm)	(Unit Plant−1)			(Kg Plant−1)		(t ha−1)
Hybrid
Fascínio	14.0 ± 1.10 a	17.9 ± 3.4 b	4.42 ± 2.00 a	46.6 ± 6.60 a	1.30 ± 0.30 b	0.74 ± 0.40 a	17.4 ± 3.7 b	9.92 ± 4.80 a
Thaíse	12.0 ± 0.90 b	22.2 ± 4.5 a	0.61 ± 0.50 b	40.6 ± 7.80 b	2.10 ± 0.40 a	0.14 ± 0.10 b	28.0 ± 5.8 a	1.96 ± 1.60 b
Soil cover
Uncovered soil	12.5 ± 1.20	17.4 ± 2.70	2.31 ± 2.10	41.4 ± 5.40	1.48 ± 0.40	0.41 ± 0.30	19.8 ± 5.3	5.50 ± 4.40
Plastic mulching	13.4 ± 1.30	20.9 ± 5.10	3.62 ± 3.10	47.3 ± 9.80	1.76 ± 0.70	0.66 ± 0.50	23.5 ± 8.8	8.84 ± 7.10
Sorghum	12.5 ± 1.30	20.1 ± 4.20	2.39 ± 2.10	45.0 ± 7.90	1.77 ± 0.40	0.41 ± 0.30	23.7 ± 5.5	5.56 ± 4.40
Sudan grass	13.5 ± 1.30	21.7 ± 5.30	1.93 ± 2.10	40.8 ± 7.00	1.81 ± 0.60	0.33 ± 0.30	24.1 ± 8.6	4.47 ± 4.40
Pearl millet	12.9 ± 1.70	20.0 ± 3.70	2.33 ± 2.10	43.6 ± 6.30	1.68 ± 0.50	0.40 ± 0.40	22.5 ± 6.1	5.35 ± 4.80
F values
Hybrid	39.5 *	11.7 *	95.2 *	10.2 *	56.8 *	74.3 *	56.8 *	74.3 *
Soil cover	1.75 ns	1.30 ns	2.17 ns	1.63 ns	1.25 ns	2.64 ns	1.25 ns	2.64 ns
Hybrid × Soil cover	0.98 ns	0.56 ns	0.46 ns	0.42 ns	0.940 ns	0.29 ns	0.94 ns	0.29 ns
C.V. (%)	7.87	19.7	49.0	13.5	19.6	49.1	19.6	49.1

Means followed by the same lowercase letter in the columns do not differ among themselves statistically, according to the Scott-Knott test at 5%. Analysis of variance: * p-value ≤ 0.05 significant at 5% probability; ^ns not significant, by F-test. All data are expressed as the mean ± standard error. C.V., coefficient of variation.

). The Thaíse hybrid had the highest number of small-sized fruits, with a 19.3% difference compared to the Fascínio hybrid. However, the Fascínio hybrid had the highest number of large fruits, with a percentage difference of 86.2% compared to the Thaíse hybrid (Table 4). The Fascínio hybrid had an average total number of commercial fruits (TNCF) of 46.6 fruits, an increase of 12.8% in relation to the Thaíse hybrid (40.6 fruits), with no influence of the type of coverage used (Table 4).

Considering fruit production per plant (kg plant⁻¹) for small fruits (PSF), there was no interaction between hybrid factors and soil cover, with an isolated effect observed only for hybrids (Table 4). As a result, the hybrid Thaíse average yield was 2.10 kg plant⁻¹, corresponding to 38.1% more than the Fascínio hybrid production, which was 1.30 kg plant⁻¹ (Table 4). In contrast, there was an isolated effect for the hybrid factor for the variable fruit production per plant for large-sized fruits (PLF); thus, the hybrid Fascínio average yield was 0.74 kg plant⁻¹, corresponding to 81.1% more than the Thaíse hybrid production, which was 0.14 kg plant⁻¹ (Table 4).

An isolated effect was verified for the hybrid factor in the variable total fruit production by size for small-sized fruits (TYS) (t ha⁻¹) (Table 4). The Thaíse hybrid produced 28.0 t ha⁻¹, representing an increase of 37.9% compared to the Fascínio hybrid (17.4 t ha⁻¹). When analyzing the total fruit production by size for large-sized fruits (TYL) (Table 4), an isolated effect was verified for the hybrid factor, with a yield of 9.92 t ha⁻¹ for the Fascínio hybrid, compared to 1.96 t ha⁻¹ for the Thaíse hybrid, representing an increase of 80.2%.

The use of soil cover (mulching) creates a favorable microclimate for plant root growth and development [39], enhancing root growth in young tomato plants immediately after planting [36]. Although the use of soil cover eliminates weeds, there is also a limitation on the number of pathogens [40]. Specifically, the application of polyethylene or polypropylene films can increase the yield of many plant species [41,42], as verified in the present study on tomatoes.

However, notably, despite the treatments with plant biomass coverings (sorghum, Sudan grass, and pearl millet) with similar tomato yield to that of the uncovered soil, as evidenced in this study, when uncovered soil is used for tomato cultivation in various consecutive years, soil degradation and wear will occur, affecting the soil microclimate and consequently decreasing the yield and quality of tomato fruits, making the uncovered soil unfeasible for cultivation [9].

3.2. Chemical, Physical, and Biochemical Quality of Fruits

3.2.1. Chemical

There were no significant interactions or isolated effects on the chemical characteristics of hydrogen potential (pH), soluble solids (SS), titratable acidity (TA), or maturation index (RATIO) of tomato fruits of the Fascínio and Thaíse hybrids cultivated in different soil covers (

Table 5. Effect of tomato hybrid and soil cover on hydrogen potential (pH), soluble solids (SS), titratable acidity (TA) and maturation index (RATIO); fruit variables: production of medium size fruits per plant (PMF), total yield of medium-sized fruits (TYM); and post-harvest mass loss (PHMASS), of creeping fresh market tomato hybrids. Tangará da Serra, Mato Grosso, Brazil, 2019.

Source of Variation	Chemical Variables				Fruit Production Per Plant	Total Fruit Production	Post-Harvest
	pH	SS	TA	RATIO	PMF	TYM	PHMASS
		(°Brix)	(%)		(Kg Plant−1)	(t ha−1)	(%)
Hybrid
Fascínio	4.04 ± 0.20	3.66 ± 0.30	0.44 ± 0.10	8.38 ± 0.90	2.96 ± 0.40	39.5 ± 6.00	8.75 ± 2.90
Thaíse	4.07 ± 0.20	3.57 ± 0.30	0.41 ± 0.10	8.67 ± 1.20	2.78 ± 1.00	37.2 ± 13.0	9.03 ± 4.10
Soil cover
Uncovered soil	4.08 ± 0.30	3.80 ± 0.40	0.47 ± 0.10	8.10 ± 0.90	2.99 ± 0.90	40.0 ± 11.4	10.0 ± 4.20
Plastic mulching	4.15 ± 0.20	3.75 ± 0.30	0.42 ± 0.10	8.91 ± 1.40	3.18 ± 0.70	42.4 ± 9.40	7.29 ± 2.10
Sorghum	4.00 ± 0.20	3.54 ± 0.20	0.40 ± 0.10	8.88 ± 0.90	3.01 ± 0.60	40.2 ± 8.30	9.44 ± 2.50
Sudan grass	4.06 ± 0.10	3.52 ± 0.20	0.41 ± 0.10	8.66 ± 1.10	2.31 ± 0.70	30.9 ± 9.90	5.58 ± 3.10
Pearl millet	4.00 ± 0.10	3.47 ± 0.20	0.43 ± 0.10	8.06 ± 0.90	2.86 ± 0.50	38.2 ± 7.30	9.15 ± 4.50
F values
Hybrid	0.16 ns	0.90 ns	1.90 ns	0.66 ns	0.80 ns	0.80 ns	0.06 ns
Soil cover	0.57 ns	1.73 ns	1.89 ns	1.06 ns	2.21 ns	2.21 ns	0.64 ns
Hybrid × Soil cover	0.35 ns	0.07 ns	0.89 ns	0.95 ns	0.34 ns	0.34 ns	0.79 ns
C.V. (%)	5.82	8.71	12.7	13.4	21.9	21.9	41.1

Analysis of variance = ^ns not significant, by F-test at 5% probability. All data are expressed as the mean ± standard error. C.V., coefficient of variation.

).

For pH, the averages observed were close to 4.00, which reduced the proliferation of microorganisms, increased the durability of the fruit, and required less sterilization cost for commercialization [43]. The observed °Brix values were similar (3.60 °Brix). The levels found were in the ideal quality range for tomato fruits above 3.00 °Brix [43,44]. Antônio et al. [45] found results close to this study, with values between 3.00 and 4.00 °Brix. However, Martins et al. [46] revealed higher mean values above 4.40 °Brix, probably because they are indeterminate hybrids, which can be more effective in the deposition of sugars.

Considering the relationship between soluble solids (SS) and titratable acidity (TA), the fruits had an average of 8.55, which is close to the ideal maturation index (RATIO) of 10, indicating that the fruits have a smoother and less acidic flavor [44].

3.2.2. Physical

An isolated effect was observed for hybrids considering the peduncle thickness variable (PEDUNC); the Fascínio hybrid had the greatest peduncle thickness (14.0 mm) compared to the Thaíse hybrid (12.0 mm), with a greater difference of 14.5% (Table 4). In a study evaluating the quality of different fresh market tomato hybrids in a protected environment, peduncle thickness values were, on average, 12.5 mm, and fruit wall thickness was, on average, 8.40 mm, consistent with values in this present study [2].

There were no significant interactions or isolated effects on the physical characteristics of the production of medium-sized fruits per plant (PMF), the total yield of medium-sized fruits (TYM), or postharvest mass loss (PHMASS) of tomato fruits from the Fascínio and Thaíse hybrids cultivated in different soil covers (Table 5).

There was an interaction between the creeping fresh market tomato hybrids and soil coverings for the variable fruit wall thickness (FWT) (

Table 6. Effect of tomato hybrid and soil cover on fruit wall thickness (FWT) and biochemical attributes (Lycopene and β-carotene) of creeping fresh market tomato hybrids (Fascínio and Thaíse), produced in different soil covers (uncovered soil, plastic mulching, sorghum, Sudan grass and pearl millet). Tangará da Serra, Mato Grosso, Brazil, 2019.

Variables	Soil Cover	Tomato Hybrids		F Values			C.V.
		Fascínio	Thaíse	Soil Cover	Hybrids	Soil Cover× Hybrids	(%)
Fruit wall thickness (mm)	Uncovered soil	6.98 ± 0.30 Bb	7.70 ± 0.50 Aa	2.78 *	8.75 *	2.86 *	5.38
	Plastic mulching	8.01 ± 0.30 Aa	7.97 ± 0.40 Aa
	Sorghum	7.04 ± 0.40 Bb	8.09 ± 0.30 Aa
	Sudan grass	7.58 ± 0.30 Aa	7.51 ± 0.30 Aa
	Pearl millet	7.39 ± 0.30 Ab	7.63 ± 0.20 Aa
Lycopene (µg 100 g−1)	Uncovered soil	490 ± 21.1 Aa	146 ± 11.3 Bc	100 *	1453.3 *	164 *	5.71
	Plastic mulching	317 ± 13.9 Ad	212 ± 12.3 Ba
	Sorghum	392 ± 7.50 Ac	153 ± 5.70 Bc
	Sudan grass	435 ± 9.90 Ab	185 ± 2.70 Bb
	Pearl millet	175 ± 21.5 Ae	187 ± 7.80 Ab
β-carotene (µg 100 g−1)	Uncovered soil	133 ± 14.6 Ab	73.6 ± 6.10 Ba	11.6 *	21.9 *	8.80 *	29.0
	Plastic mulching	31.6 ± 8.60 Ac	48.5 ± 17.2 Aa
	Sorghum	67.2 ± 25.8 Ac	73.0 ± 9.00 Aa
	Sudan grass	167 ± 48.3 Aa	55.0 ± 10.2 Ba
	Pearl millet	121 ± 30.8 Ab	85.6 ± 33.9 Aa

Means followed by the same uppercase letter in the lines and same lowercase letters in the columns do not differ among themselves statistically, according to the Scott Knott test at 5%. Analysis of variance = * p-value ≤ 0.05 significant at 5% probability. All data are expressed as the mean ± standard error. C.V., coefficient of variation.

). The Thaíse hybrid showed greater fruit wall thickness in the uncovered soil and sorghum covers than the Fascínio hybrid, with no difference between the hybrids for the other soil covers, with increments of 9.35 and 13.0%, respectively. Analyzing the effect of cover crops as a function of hybrids, there was a difference in the Fascínio hybrid, such that plastic mulching and Sudan grass cover provided the greatest fruit wall thickness. For the Thaíse hybrid, the soil cover did not affect this variable.

The peduncle (peduncular scar) and fruit wall thickness of fresh market tomatoes are important characteristics for higher fruit quality and post-harvest longevity, as fruits with thicker walls have higher weights and increased post-harvest conservation due to greater firmness and are less susceptible to wilting. Conversely, fruits with smaller peduncular thickness may show less mass reduction, allowing increased post-harvest conservation [47].

3.2.3. Biochemical

There was a significant interaction for lycopene between Fascínio and Thaíse tomato hybrids as a function of soil cover (Table 6). Among the hybrids, the highest levels were provided by the Fascínio hybrid in treatments with uncovered soil, plastic mulch, sorghum, and Sudan grass. The increments were 70.2, 33.2, 61.1, and 57.5%, respectively. No difference was observed in pearl millet. The analysis of soil cover according to tomato hybrids showed that the highest levels of Fascínio hybrids were observed in treatments with uncovered soil, Sudan grass, sorghum, plastic mulching, and pearl millet. In the Thaíse hybrid, the highest values were recorded for plastic mulching, followed by Sudan grass and pearl millet, in which uncovered soil and sorghum did not differ.

Considering the β-carotene, a significant interaction was observed between the creeping fresh market tomato hybrids and the soil coverings (Table 6). Comparing the tomato hybrids as a function of soil coverage, a difference was observed with higher values of β-carotene for the hybrid Fascínio, for the uncovered soil and Sudan grass, with no difference for the other covers. The percentage increments were 44.6 and 67.0%, respectively. In the soil coverage analysis for each tomato hybrid, Sudan grass differed from the other covers; uncovered soil and pearl millet did not differ, as did plastic mulching and sorghum for the Fascínio hybrid. There were no differences in the soil cover of the Thaíse hybrid.

For the Fascínio tomato hybrid, the lycopene contents ranged from 175 µg 100 g⁻¹ (covered with pearl millet) to 490 µg 100 g⁻¹ (uncovered soil), and for the Thaíse hybrid, they were 146 µg 100 g⁻¹ (uncovered soil) to 212 µg 100 g⁻¹ (covering with plastic mulching). β-carotene contents ranged from 31.6 µg 100 g⁻¹ (Fascínio/plastic mulching) to 133 µg 100 g⁻¹ (Fascínio/uncovered soil) and 48.5 µg 100 g⁻¹ (Thaíse/mulching plastic) to 85.6 µg 100 g⁻¹ (Thaíse/pearl millet). These results were below the averages of Silva et al. [48] (369 and 245 µg 100 g⁻¹). Nellis et al. [13] found values of 26.5 mg 100 g⁻¹ for lycopene and 25.7 mg 100 g⁻¹ for β-carotene. Seabra Júnior et al. [3] found 0.40 mg 100 g⁻¹ of lycopene and 0.04 mg 100 g⁻¹ of β-carotene for the Fascínio hybrid, where they acknowledge that they are specific characteristics that increase the fruit value, catering to the most demanding consumers and these elements contribute to the prevention of diseases and provide an important antioxidant function in human consumption.

In tomato cultivars, there is a response to phosphorus and potassium fertilization in relation to the greater influence of genetic material on the production of β-carotene and the total sugar content in the fruits than on the treatments used. These effects have also been attributed to the ability of each genotype to respond to the management strategies used [48]. Notably, other factors besides nutrition and genetic material influence the levels of sugars and carotenoids in tomato fruits.

In terms of plant growth, production, and quality of tomato fruits, it was evidenced that soil cover with biodegradable material had the highest concentration and activity of antioxidants. In contrast, the black polyethylene cover and uncovered soil showed the lowest values for polyphenols, flavonoids, and ascorbic acid, and the polyethylene cover had the lowest concentration of carotenoids and the soil exposed to the lowest antioxidant activity [2]. Environmental factors, such as greater exposure to light and high temperatures, occasionally lead to fruits with less intense color and, consequently, a lower concentration of lycopene; however, the concentration of β-carotene was not affected [49].

3.3. Principal Components Analysis (PCA)

Principal component analysis was applied to establish a descriptive model for grouping the analyzed variables in terms of the different soil covers used to plant the two tomato hybrids (Fascínio and Thaíse). A biplot graphic representation that expresses the correlation between the variables and principal components is illustrated in Figure 1.

PC1 and PC2 explained 70.5% of the variance in the data (Figure 1). The first principal component (PC1) explained the highest percentage of data variability (43.4%) and was responsible for grouping variables according to the analyzed genotypes. The treatments applied to the Fascínio hybrid were grouped as PC1+, and the treatments applied to the Thaíse hybrid were grouped as PC1-. Regardless of the treatment used (soil cover), the Fascínio hybrid showed a higher total yield of medium-sized fruits (TYM, t ha⁻¹) and total yield of large-sized fruits (TYL, t ha⁻¹), a greater production of medium size fruits per plant (PMF, kg plant⁻¹) and production of large size fruits per plant (PLF, kg plant⁻¹), a greater number of medium size fruits per plant (MF, unit plant⁻¹) and several large fruits per plant (LF, unit plant⁻¹), the greater total number of fruits per plant (TNFP, unit plant⁻¹⁾ and the total number of commercial fruits per plant (TNCF, unit plant⁻¹), and higher yield, mainly non-commercial yield (NCY, t ha⁻¹). In contrast, the Thaíse hybrid was characterized by a lower yield, higher total yield of small-sized fruits (TYS) (t ha⁻¹), higher production of small fruits per plant (PSF, kg plan⁻¹), higher number of small fruits per plant (SF, unit plant⁻¹), and higher post-harvest mass loss (PHMASS, %).

Notably, large-sized fruits, with a size above 60.0 mm, have a higher market value and price per batch, with greater commercial value. In contrast, small-sized fruits have low consumer acceptance, making it unfeasible for tomato growers to sell market products competitively [50], emphasizing the importance of promoting the use of the Fascínio hybrid in tomato crops. Furthermore, the interaction between genotype and environment is directly related to the characteristics of fruit size, in addition to temperature and humidity, leaf area, light intensity, and position of the plant bunch [51]; therefore, studies in other growing regions are required to verify the results obtained with the hybrids used in the present study.

For the Fascínio hybrid, the treatments that showed the greatest production responses (larger fruit size and greater peduncle thickness) were in the soil cover with plastic mulch and sorghum (PC2+). In addition to the production attributes, the Fascínio hybrid had a higher soluble solids (SS) content, which also occurs with other “Italian” tomato hybrids [47]. The Fascínio hybrid had a high yield, greater production of medium and large fruits per plant, and higher precocity index, in addition to fruits with superior quality (higher SS content, better aroma, and flavor) and with less mass loss during storage, when compared to other tomato hybrids [52].

The Fascínio hybrid also showed higher levels of bioactive compounds, regardless of the soil cover used for tomato planting. However, in addition to factors intrinsic to the plant (genetic), the content of these substances can be affected by the environmental and nutritional conditions of the crops (agronomic conditions) [53]. This was verified in the present study, where the type of coverage used influenced the content of these antioxidant compounds in the different hybrids. Treatments with soil covered with Sudan grass and uncovered soil resulted in fruits with higher lycopene and β-carotene contents (PC1+) (Table 6 and Figure 1), unlike the attributes of fruit production.

A negative correlation was reported between yield, fruit size, and bioactive compound content [3,54,55]. Therefore, the content of these bioactive substances in tomatoes depends on the harvest, the agronomic interventions, and the genotype analyzed. According to these studies, high levels of these antioxidant compounds in the fruits are detected when coverings are not used during planting (phenolic compounds and carotenoids) [55].

3.4. Pearson Correlation Analysis

There was a strong correlation between the studied variables of the two hybrids of creeping fresh market tomatoes with determinate growth habits (Thaíse and Fascínio) cultivated in different soil covers. There was a positive Pearson correlation (≥0.90) (Figure 2), at 5% probability, between the number of small fruits per plant (SF) and the production of small-sized fruits per plant (PSF) and the total yield of small-sized fruits (TYS); between the number of medium-sized fruits per plant (MF) and the number of large fruits per plant (LF), the total number of commercial fruits per plant (TNCF), the production of large-sized fruits per plant (PLF), and the total yield of large-sized fruits (TYL); between the number of large fruits per plant (LF) and the production of large-sized fruits per plant (PLF) and the total yield of large-sized fruits (TYL); between the production of small-sized fruits per plant (PSF) and the total yield of large-sized fruits (TYL); between the production of medium-sized fruits per plant (PMF) and the total yield of medium-sized fruits (TYM); between the production of large-sized fruits per plant (PLF) and the total yield of large-sized fruits (TYL); between total production per plant (TP) and total yield (TY); and between commercial production per plant (CP) and commercial yield (CY). Therefore, there was a highly positive correlation between the physical variables of tomato hybrids (Figure 2). The post-harvest mass loss showed no correlation with the other variables evaluated (Figure 1 and Figure 2).

These results are in agreement with Kumar et al. [56], who found a positive relationship between fruit yield per plant and the number of fruits per plant. The relationships between characteristics may change depending on the cultivar or management adopted for the crop [57]. Thus, the type of management adopted in this study, different soil covers in the cultivation of two creeping fresh market tomato hybrids, may have interfered with the relationships between characteristics since soil covers can influence nutrient availability, water retention, soil temperature, and weed control, which can affect both the production and chemical and physical quality of tomato fruits [58,59,60,61].

Sari et al. [62] investigated the linear relationships between cherry tomato characteristics and concluded that production is directly related to the number of fruits produced, while the individual weight of each fruit has little influence on total production. In turn, Rodrigues et al. [63] observed that the average fruit weight and the total number of fruits have high magnitudes and indirect effects on the total production of salad tomatoes.

The use of polyethylene film can increase the yield of many plant species [41,42], as detected in this present study with two tomato hybrids. However, the synthesis of bioac-tive compounds, such as carotenoids, depends on the thermal requirements during the planting of different crops. For example, in tomatoes, the maximum synthesis of lycopene occurs at a temperature between 25 and 30 °C, whereas in carrots and melons, the synthe-sis of carotenoids such as β-carotene occurs at temperatures between 15–20 °C and 30 °C, respectively [42]. In addition, polyethylene films can reduce the reflection of sunlight and, consequently, result in lower levels of these pigments [64,65], which may explain the re-sults obtained in the present study.

The tomato planting system on vegetable coverings improves the moisture condition and beneficial microbial population in the soil, rational use, and efficiency in drip irriga-tion and fertigation [59]. Grasses, in particular, protect the soil against the loss of soil, wa-ter, and nutrients throughout almost the entire tomato cycle [66]. In several studies, the no-tillage system for vegetables can reduce water losses by surface runoff by up to 80% and soil losses by erosion by up to 90%. This reduction is mainly due to the maintenance of cover over the soil surface throughout the year and to the improvement of the soil structure [66,67].

In areas with conventional sowing, when the tomato no-tillage system is started after six years, there is a significant increase in organic matter levels and an increase in soil fertility, especially regarding the levels of phosphorus, calcium, and also an increase in soil cation exchange capacity [67]. The possibility of reducing the fertilization of planting in relation to the conventional one was also observed. Natural fertility increments were verified, which helps in cultivation in general. Nutrient accumulation curves for tomatoes show that accumulation and exportation from productive areas follow a pattern: K > N > P ≥ Ca > S > Mg [67].

4. Conclusions

The management of soil coverage influences the production and quality of tomato fruits, except for chemical and post-harvest characteristics, maintaining ideal levels for the commercialization of tomatoes grown in all soil coverings. The Fascínio hybrid had better production attributes: higher total production of total and commercial fruits per plant and larger fruits, especially when grown on soil cover with plastic mulch. In addition, the Fascínio hybrid also had fruits with higher levels of bioactive compounds (lycopene and β-carotene). However, unlike the production attributes, higher levels of lycopene and β-carotene were verified in tomato cultivation in the uncovered soil and Sudan grass cover treatments, respectively. The use of soil cover in the cultivation of the two tomato hybrids (Thaíse and Fascínio) did not affect the chemical variables (pH, soluble solids, titratable acidity, and maturation index) of tomato fruits. For plant biomass production, pearl millet and Sudan grass were prominent from other soil cover types, showing lower decomposition rates and, consequently, longer half-lives. The soil covering with plastic mulching is prominent compared to the other soil coverings used in this study, providing higher total (111 t ha⁻¹) and commercial (74.4 t ha⁻¹) yields, regardless of the tomato hybrid analyzed.