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Article

Can Molybdenum Fertilization Enhance Protein Content and Digestibility of Sorghum Single Cropped and Intercropped with Cowpea?

by
Nágila Sabrina Guedes da Silva
1,
Alexandre Campelo de Oliveira
1,
Baltazar Cirino Júnior
1,
Rhaiana Oliveira de Aviz
1,
Kedes Paulo Pereira
2,
Domingos Sávio Marques de Menezes Vieira
1,
Claudenilde de Jesus Pinheiro Costa
3,
Jucelane Salvino de Lima
2,
Jamiles Carvalho Gonçalves de Souza Henrique
4 and
Evaristo Jorge Oliveira de Souza
1,*
1
Academic Unit of Serra Talhada, Federal Rural University of Pernambuco, Gregório Ferraz Nogueira Ave., Serra Talhada 56909-535, Brazil
2
Animal Science, Federal University of Alagoas, BR-104 highway, Rio Largo 57100-000, Brazil
3
Animal Science, Federal Rural University of Pernambuco, Dom Manoel de Medeiros Ave., Recife 52171-900, Brazil
4
Campus I Lot. Cidade Universitaria, Federal University of Paraiba, Areia 58051-900, Brazil
*
Author to whom correspondence should be addressed.
Grasses 2025, 4(3), 28; https://doi.org/10.3390/grasses4030028
Submission received: 25 April 2025 / Revised: 23 May 2025 / Accepted: 17 June 2025 / Published: 2 July 2025
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Versions Notes

Abstract

Molybdenum fertilization represents a viable alternative for improving forage quality, potentially complementing or enhancing the effects of nitrogen fertilization. This study aimed to determine whether foliar or soil application of molybdenum would increase the crude protein content and digestibility of sorghum cultivated as a monoculture or intercropped with cowpea. The first experiment followed a 2 × 2 + 2 factorial design, including two application methods (foliar or soil), two cropping systems (monoculture or intercropping), and two additional control treatments (with and without molybdenum). In the second experiment, a split-plot design was used to assess the effects of molybdenum fertilization on the in situ digestibility of sorghum from monoculture and intercropping systems. Molybdenum fertilization increased the levels of crude protein, total carbohydrates, and soluble fractions. It also enhanced the disappearance rate, potential degradability, and effective degradability of sorghum, regardless of the application method or cropping system. Foliar or soil application of molybdenum is recommended to optimize the crude protein content and in situ digestibility of sorghum cultivated either as a monoculture or intercropped with cowpea.

Graphical Abstract

1. Introduction

During critical periods of drought, forage availability and forage quality are two limiting factors for livestock production in arid and semi-arid regions [1]. Thus, implementing alternative management strategies, such as grass–legume mixtures and low-cost fertilization, is paramount to maximize forage production [2,3]. Intercropping grass and legume species benefits forage production more than monocultures because it promotes higher dry matter yields, greater stimulus to biological nitrogen fixation, higher water utilization efficiency, and improvement in soil characteristics [4,5,6].
Molybdenum fertilization is a low-cost alternative to conventional nitrogen fertilization. Molybdenum is a key component of the enzymes involved in electron transport and various biochemical reactions (e.g., xanthine oxidase dehydrogenase, sulfite oxidase, and aldehyde oxidase), including reductase and nitrogenase, which are essential for the conversion of atmospheric nitrogen into ammonium (NH4+) [7,8]. Nitrogenase is responsible for atmospheric nitrogen fixation, while reductase catalyzes the reduction in nitrate to nitrite and subsequently to ammonium (NH4+) [9]. Due to its role in nitrogen metabolism, molybdenum deficiency can reduce the productivity of leguminous species [9,10]. This raises the following question: can molybdenum fertilization enhance the crude protein content and digestibility of sorghum grown in monoculture or intercropped with cowpea?
Forage sorghum (Sorghum bicolor (L.) Moench) is widely used for animal feeding in semi-arid environments due to its high forage yield, palatability, and adaptability to ruminant diets [11,12]. Cowpea (Vigna unguiculata (L.) Walp) is commonly used in intercropping systems in arid and semi-arid regions due to its high protein content and moderate tolerance to water stress [13,14]. Additionally, Ref. [15] reported that cowpea can fix atmospheric nitrogen through symbiosis with nitrogen-fixing bacteria, and that the nitrogen from this biological fixation may benefit the grass species intercropped with cowpea.
The quality of sorghum, cowpea, and other forage plants is mainly attributed to their crude protein content (the most expensive nutrient fraction) and digestibility [16]. It is well established that animals consume smaller quantities of high-quality forage because of its greater digestibility, allowing them to meet their nutritional requirements more efficiently [17,18]. This highlights the importance of evaluating both nutrient composition and digestibility. However, nutrient composition alone cannot determine forage quality, as some nutrient fractions may not be available for fermentation by rumen microorganisms. In contrast, in situ digestibility better reflects the interactions between rumen microorganisms and the feed.
This study proposes the use of molybdenum as a strategy to enhance crude protein content and digestibility of sorghum under different cropping systems. This low-cost and still underexplored approach holds the potential to improve livestock production efficiency in semi-arid regions, which are typically characterized by low soil fertility and water scarcity. It is hypothesized that molybdenum application, regardless of the method of application or cropping system, increases the availability of assimilable nitrogen, thereby improving the bromatological composition and digestibility of sorghum.
In this context, the objective of this study was to evaluate whether molybdenum fertilization, applied either via foliar spray or soil, can improve the crude protein content and digestibility of sorghum grown in monoculture or intercropped with cowpea.

2. Materials and Methods

2.1. Research Site

This study was conducted at the Academic Unit of Serra Talhada (UAST; 07°59′31″ S; 38°17′54″ W), part of the Federal Rural University of Pernambuco (UFRPE), located in Serra Talhada, Pernambuco, Brazil, at an altitude of 444 m. According to the Köppen–Geiger climate classification [19], the climate in Serra Talhada is classified as BSwh’ (hot and dry semi-arid). The region has an average annual precipitation of 642 mm, mostly concentrated between December and May, an average annual temperature of 25.2 °C, and a relative humidity of 63% [20].

2.2. Experiment 1

2.2.1. Crop Establishment and Harvest

The first experiment was conducted over two harvest cycles. Sorghum (Sorghum bicolor L., cultivar IPA-467) was sown on 20 January 2020, with the first harvest on 20 May 2020, and a second regrowth harvest on 30 September 2020. Cowpea was sown twice: initially on 28 January 2020 and again on 20 May 2020. Each cycle lasted approximately 120 days.
Crops were grown as intercropped and single systems. Sorghum was planted into furrows approximately 5 cm deep, with seeds deposited along the entire length of the furrow. Stands were thinned 20 days after seedling emergence for the selection of 20 plants per linear meter. The spacing used was 1.0 m × 0.1 m. Cowpea was sown in planting holes with 5 cm depth and three seeds per hole. Fifteen and twenty days after emergence, the cowpea stand was thinned, leaving only one plant per hole. For cowpea in the intercropped system, the spacing used was 1.0 × 0.2 m.
The stands were irrigated with saline water showing pH and electrical conductivity values of 7.27 ± 0.18 and 2120 ± 20.23 µS/cm, respectively. The irrigation water depth used was 50%. The irrigation system consisted of ten 12 m long drip strips, spaced 0.75 m apart, totalizing 90 m2. The irrigation strips had six plots consisting of five 3 m long drip lines, totaling 11.25 m2 of total area and 4.5 m2 of useful area, identified as the three 2 m long central lines. Stands were irrigated three times per week, and cultural practices were performed every 30 days.
Meteorological data were monitored throughout planting cycles by a weather station belonging to INMET and located at UAST. The accumulated precipitation and average evapotranspiration were 588 mm and 7 mm/day, respectively.

2.2.2. Soil Characterization

At the research site, the soil was classified as Eutroferric Haplic Cambisol [21]. Prior to crop establishment, soil samples were randomly collected from 15 locations across the site at depths ranging from 0 to 40 cm to determine their physical and chemical properties. The characterization of these samples was conducted following the methodologies described by [22] (Table 1).

2.2.3. Treatment Application

Molybdenum (0.18 mg/kg), diluted in two liters of water, was applied at this concentration to each 6 m2 plot. The foliar treatment was applied using an agricultural knapsack sprayer (model Nine54).
Applications were carried out 25 days after cowpea emergence and again 25 days after sorghum cutting, corresponding to one application per cycle. During foliar fertilization, adjacent plots were covered with plastic tarpaulin to avoid cross-contamination. Soil fertilization was performed using a manual watering can.

2.2.4. Sorghum Harvest and Sample Processing

Each production cycle lasted 120 days, with harvesting carried out when the sorghum dry matter (DM) content reached between 30% and 35%. At the end of each cycle, five representative plants were selected from the useful rows of each plot to constitute a composite sample. The cutting was performed manually using a machete; the harvested material was then labeled and transported to be chopped using a silage machine (JF Máquinas Agrícolas LTDA, model JF 40 Maxxium, Itapira, Brazil).
After grinding, approximately 900 g of sample was collected from each experimental plot, weighed, and placed into labeled paper bags to be dried in a forced-air oven at 55 ± 5 °C for 72 h.
The dried samples were ground in a Wiley knife mill using a 4 mm mesh sieve for degradability testing and a 1 mm mesh sieve for the laboratory analyses. Ground samples were stored in hermetically sealed jars at −20 °C.

2.2.5. Bromatological Composition Analysis

Laboratory analyses were conducted following the methods established by the Association of Official Analytical Chemists (AOAC) for the determination of dry matter (DM; method 967.03), mineral matter (MM; method 942.05), crude protein (CP; method 988.05), and lignin using 72% sulfuric acid (method 973.18) [23]. Neutral detergent fiber (NDF) was analyzed with the aid of alpha-amylase, as recommended by [24]. Ether extract (EE; method 920.29) was determined using an ANKOM XT-15 extractor, according to [24]. Total carbohydrates (TCs) and non-fibrous carbohydrates (NFCs) were estimated using equations proposed by [25,26], respectively.

2.3. Experiment 2

2.3.1. Evaluation of In Situ Digestibility

The in situ assay was conducted at the Ruminant Research Unit of UAST/UFRPE. The experimental period lasted 28 days, with the first 14 days allocated for adaptation to the experimental diets and the remaining 14 days for rumen incubation. Incubations were performed using three non-castrated male Santa Inês sheep, surgically fitted with rumen cannulas, with an average body weight of 50 ± 2 kg. The animals were housed in individual pens measuring 2.0 × 2.0 m, with free access to feed and water. Experimental diets were formulated at a roughage-to-concentrate ratio of 80:20. The roughage consisted of elephant grass (Pennisetum purpureum), and the concentrate mix included corn meal, cottonseed cake, and a mineral supplement.
The experimental treatments mirrored those evaluated in Experiment 1, resulting in six treatments in Experiment 2: molybdenum application (to the soil or to the foliage), a control treatment without molybdenum, and two sorghum cultivation systems (monocropped or intercropped with cowpea).
Samples (2 g) from each treatment were placed in nylon bags (50 µm porosity), previously weighed and labeled, and incubated in duplicate in the rumen of the sheep. The amount of material incubated followed the proportion recommended by [27]: 14.3 mg of sample per cm2.

2.3.2. Incubation

Samples from Experiment 1 were incubated for 0, 2, 4, 6, 12, 24, 48, 72, and 96 h. Two replicates per sample and incubation time were inserted into the rumen of each cannulated animal. After the incubation period, the bags were simultaneously removed from the rumen and immediately immersed in cold water. They were then rinsed under running water until all residues from the rumen contents were completely eliminated. Finally, the samples were dried in a forced-air oven at 55 °C for 72 h.

2.3.3. Determination of In Situ Digestibility

After drying, the incubated samples were removed from the oven and weighed to determine dry matter disappearance. Potential degradability (PD) was estimated using the model proposed by [28]: PD(t) = a + b (1 − e^ – ct), where “a” is the soluble fraction, “b” is the potentially degradable fraction (i.e., the portion degraded over time), and “c” is the rate constant of degradation of fraction “b” per hour.
The soluble fraction “a” was determined by placing two samples in a 39 °C water bath for 15 min. Effective degradability (ED), which reflects the portion of the feed actually degraded in the rumen, was calculated according to [29]: ED = a + [(b × c)/(c + k)] × exp [–(c + k) t0]. In this equation, “k” represents the ruminal passage rate, assumed to be 2%, 5%, or 8% per hour [30], and “t0” is the lag time. Finally, the non-degradable fraction (ND) was estimated as ND = 100 − (a + b).

2.4. Experimental Design and Statistical Analyses

2.4.1. Experiment 1

The bromatological composition of the plants was evaluated using a completely randomized block design. Treatments were arranged in a 2 × 2 + 2 factorial scheme, comprising two molybdenum application methods (120 g/ha applied to the soil or to the leaves), two cropping systems (monocropped sorghum or sorghum intercropped with cowpea), and two control treatments without molybdenum fertilization (monocrop/intercrop), with three replications. Data from Experiment 1 were subjected to analysis of variance (ANOVA) and Tukey’s test for mean comparison, using Statistical Analysis System (SAS) software, version 9.1. The UNIVARIATE procedure (PROC UNIVARIATE) was used to assess data normality (Shapiro–Wilk test at a 5% significance level). The standard error of the mean was estimated based on the original data. Treatment effects were considered statistically significant at p < 0.05. The adopted statistical model was yklj = μ + bj + Ak + Bl + (AB)kl + eklj, where yklj = observation, μ = overall mean, bj = effect of molybdenum application method, Ak = effect of cropping system, (AB)kl = interaction between application method and cropping system, and eklj = random error.

2.4.2. Experiment 2

Digestibility was assessed using a completely randomized block design with three replications (animals), arranged in a split-plot scheme, where the main plots consisted of six treatments from the first experiment, and the subplots represented ruminal incubation times (0, 2, 4, 6, 12, 24, 48, 72, and 96 h).
Data on potential and effective degradability were subjected to analysis of variance (ANOVA), and means were compared using the Student–Newman–Keuls (SNK) test via the SAS statistical software. As in Experiment 1, the normality of the residuals was verified using the UNIVARIATE procedure (PROC UNIVARIATE) with the Shapiro–Wilk test at a 5% significance level. The standard error of the mean was also calculated from the original data, and differences among treatments were considered statistically significant when p < 0.05. The statistical model adopted was yijk = μ + αi + βj + (αβ)ij + γk + (βγ)jk + εijk, where yijk = observed value in subplot k of main plot j and replication i; μ = overall mean; αi = block effect; βj = main plot effect (B); (αβ)ij = main plot error (A); γk = subplot effect (C); (βγ)jk = interaction between B and C; and εijk = subplot error (B).

3. Results

3.1. Experiment 1

There was no significant interaction (p > 0.05) between molybdenum fertilization and cropping system for any of the evaluated variables. Neither the cropping system (sole sorghum or sorghum intercropped with cowpea) nor the form of molybdenum application (soil or foliar) significantly affected (p > 0.05) the contents of dry matter (DM), organic matter (OM), non-fibrous carbohydrates (NFCs), neutral detergent fiber (NDF), acid detergent fiber (ADF), or lignin (Table 2).
However, molybdenum fertilization significantly increased the crude protein (CP) content (p < 0.05), regardless of the cropping system or application method. As a result, the total carbohydrate (TC) content significantly decreased (p < 0.05) following molybdenum fertilization (Table 2).

3.2. Experiment 2

The cropping system (sole sorghum or sorghum intercropped with cowpea) and molybdenum fertilization (soil or foliar application) had no significant effect (p > 0.05) on the potentially degradable fraction (b) and the degradation rate of fraction b (c) in sorghum (Table 3). However, regardless of the cropping system and application method, molybdenum fertilization significantly increased (p < 0.05) the soluble fraction (a) of sorghum and consequently reduced (p < 0.05) the non-degradable fraction (Table 3).
Regardless of the application method, molybdenum fertilization significantly increased (p < 0.05) the potential and effective degradability rates at 2%, 5%, and 8%/h in both sole sorghum and sorghum intercropped with cowpea (Table 4).
The sorghum cultivation system (sole or intercropped), as well as the molybdenum application method (soil or foliar), did not significantly affect (p > 0.05) the dry matter disappearance rate during the initial hours of the incubation. However, after 48 h, the disappearance rate was significantly higher (p < 0.05) in treatments fertilized with molybdenum, regardless of the application method or cropping system (Figure 1).

4. Discussion

Sorghum is highly responsive to fertilizer application, particularly to nitrogen-based fertilizers. In this crop, nitrogen accumulates in an almost linear fashion until plant maturity and is the most limiting nutrient for sorghum productivity [31,32]. Molybdenum is a component of enzyme complexes involved in nitrogen metabolism and plays an important role in plant development, despite being required only in trace amounts. For instance, molybdenum is found in enzymes and proteins associated with the plant cell wall, including aldehyde oxidase, dehydrogenase, xanthine oxidase, and nitrate reductase [33,34].
Acting as an essential cofactor of the enzyme nitrate reductase (NR), molybdenum (Mo) plays a critical role in the reduction in nitrate (NO3−) to ammonium (NH4+), a central step in nitrogen (N) assimilation and a precursor to the synthesis of amino acids and proteins [35,36]. This enzymatic reaction represents one of the main limiting factors for nitrogen use efficiency in plants and is highly dependent on adequate Mo availability. The strong correlation between NR activity and sorghum productivity [37] supports the increase in crude protein (CP) content observed in this study with Mo application, regardless of the method used, corroborating the findings of [38].
The lack of significant differences between soil and foliar application routes can be attributed to the high mobility and efficient uptake of Mo by plants, regardless of the supplementation method. When available in its anionic form (MoO42−), Mo is readily absorbed by roots and translocated via the xylem, or, in the case of foliar application, rapidly internalized through leaf surfaces and redistributed to metabolically active tissues. Thus, in both application methods, Mo effectively reaches the enzymatic sites involved in nitrate assimilation, promoting a similar physiological response. Comparative studies indicate that the effectiveness of foliar versus soil Mo application may vary depending on crop species, soil conditions, and the specific response evaluated. In general, both strategies tend to enhance plant growth and productivity; however, while some studies report no significant differences between methods [39,40], others suggest a superior effect from one approach over the other [41,42].
Supporting the present results, [43] stated that molybdenum is associated with increased nitrogen (N) content in the plant (thus in protein content) through direct action on N biomass production, photosynthetic activity, and stimulation to cell division. It is noteworthy that the study site exhibited edaphoclimatic conditions favorable to molybdenum (Mo) availability and its role in the nitrogen cycle. The near-neutral soil pH (7.27) (Table 1) enhanced Mo solubility, which is predominantly present in the anionic form (MoO42−), readily absorbed by plants. Additionally, the high temperatures promoted the rapid oxidation of NH4+ to NO3−, increasing the availability of nitrogen in the nitrate form [44].
The increase in the total carbohydrate (TC) content (Table 2) in the control treatments (without molybdenum fertilization) occurred due to the reduction in the crude protein (CP) content, as TC and CP fractions are inversely related [45]. This change reflects a limitation in nitrogen metabolism by the plant in the absence of molybdenum, an essential micronutrient for the activity of both nitrogenase—an enzyme involved in biological nitrogen fixation—and nitrate reductase, responsible for the conversion of nitrate (NO3−) to nitrite (NO2−), a key step in the synthesis of nitrogenous compounds [8]. With reduced availability of assimilable nitrogen, the synthesis of nitrogenous compounds such as proteins is impaired, leading to a metabolic shift towards the production of structural carbohydrates. Consequently, there was a decrease in potentially digestible nutrients such as soluble carbohydrates, proteins, minerals, and vitamins, which in turn explains the sharp reduction in digestibility observed in Table 4 [46].
This alteration in the bromatological composition negatively affects the nutritional value of the forage, as it reduces the concentration of potentially digestible nutrients—especially proteins, minerals, and vitamins—which resulted in a significant decline in in vitro digestibility (Table 4), as previously reported by [46]. Lower digestibility directly compromises the efficiency of forage utilization by ruminants, reflected in the reduced disappearance rate in the digestive tract (Figure 1).
On the other hand, molybdenum fertilization promoted positive changes in the chemical composition of sorghum, regardless of the application method or cultivation system (Table 3). An increase in soluble fractions was observed, including soluble carbohydrates and proteins, along with a reduction in the non-degradable dry matter fraction. This behavior resulted in higher potential and effective degradation rates under different ruminal passage rates (2%, 5%, and 8%/h; Table 4), which improves the effective degradation rate of fibrous material in the digestive tract (Figure 1).
These improvements are associated with the central role of molybdenum in nitrogen assimilation by plants. The greater nitrogen availability resulting from the action of this micronutrient enhances the synthesis of nitrogenous compounds, such as proteins and amino acids, increasing the proportion of soluble fractions and reducing cell lignification, thereby improving the accessibility of fibrous substrates to ruminal microorganisms [16,19].
Furthermore, studies such as those by [47] have demonstrated that increased molybdenum application facilitates the transport and accumulation of nitrate in the aerial parts of the plant, resulting in higher protein content and, consequently, better forage nutritional quality. Ref. [48] also supports this finding, showing that molybdenum stimulates biological nitrogen fixation, contributing to the increased dry matter yield of forage plants.

5. Conclusions

The application of molybdenum fertilization at a rate of 120 g/ha is recommended, regardless of the application method (soil or foliar), to optimize the crude protein content and in situ digestibility of sorghum grown either as a sole crop or intercropped with cowpea.

Author Contributions

N.S.G.d.S. completed data curation, investigation, methodology, original draft writing, and visualization; A.C.d.O. completed project administration, supervision, methodology; B.C.J. completed data curation, investigation, methodology, R.O.d.A. completed data curation, investigation, methodology; K.P.P. completed methodology, writing—review and editing; D.S.M.d.M.V. completed data curation, investigation, methodology; C.d.J.P.C. completed data curation, investigation, methodology; J.S.d.L. completed methodology, writing—review and editing; J.C.G.d.S.H. Henrique completed writing—review and editing; and E.J.O.d.S. completed conceptualization, data curation, formal analysis, investigation, methodology, project administration, resources, supervision, writing—original draft, writing—review and editing. All authors have read and agreed to the published version of the manuscript.

Funding

This study was financed by the Foundation for the Support of Science and Technology of Pernambuco (FACEPE) grant Number IBPG-1817-5.01/19.

Data Availability Statement

Data are available from the corresponding author upon request.

Acknowledgments

The funding agency We acknowledge the Federal Rural University of Pernambuco, Serra Talhada Academic Unit (UFRPE/UAST), and the Graduate Program in Plant Production (PGPV) for providing the field area, access to laboratory, bibliographical, and technological resources, fundamental for the advancement of this research.

Conflicts of Interest

The authors declare no conflicts of interest.

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Grasses 04 00028 g001
Figure 1. Dry matter disappearance over incubation time for sorghum grown in different systems (single or intercropped) fertilized with molybdenum (applied to soil or applied to leaves) and non-fertilized with molybdenum.
Figure 1. Dry matter disappearance over incubation time for sorghum grown in different systems (single or intercropped) fertilized with molybdenum (applied to soil or applied to leaves) and non-fertilized with molybdenum.
Grasses 04 00028 g001
Table 1. Chemical and physical characterization of the soil in the experimental area.
Table 1. Chemical and physical characterization of the soil in the experimental area.
Dep.PpHKChemical Attributes
NaAlCaSARMgH + AlCSCECVESPOM
cmmg/dm3 cmolc/dcm3%
0–203836.710.480.1103.610.092.610.476.817.2893.541.511.14
20–403886.740.40.1903.90.142.670.57.167.6693.472.480.94
Physical analysis
Dep.BDPDTPNAFFTTCSFSSiltClay
cmg/cm3%%
0–201.612.5336.264.3259.0073.6044.5029.1015.9010.50
20–401.662.4732.804.3958.3172.2048.8823.3417.2010.50
Dep.—depth; P—phosphorus; pH—hydrogen potential; K—potassium; Mo—molybdenum; Na—sodium; Al—aluminum; Ca—calcium; RAS—sodium adsorption ratio; Mg—magnesium; H + Al—potential acidity; CS—cation sum; CEC—cation exchange capacity; V—base saturation; ESP—exchangeable sodium percentage; OM—organic matter; LQ—limit of quantification; BD—bulk density; PD—particle density; TP—total porosity; NA—natural sand; FF—flocculation degree; TT—total sand; CS—coarse sand; FS—fine sand.
Table 2. Bromatological composition of sorghum grown in different systems (single or intercropped), fertilized with molybdenum (via leaves or soil), and non-fertilized with molybdenum.
Table 2. Bromatological composition of sorghum grown in different systems (single or intercropped), fertilized with molybdenum (via leaves or soil), and non-fertilized with molybdenum.
VariableProduction System (S)SEMp-Value
IntercroppedSingleSAS*A
ControlApplication (A)ControlApplication (A)
LeavesSoilLeavesSoil
DM, g/kg FM3172952783182853230.770.460.310.44
OM, g/kg DM9379319249359369371.300.060.230.09
CP, g/kg DM38.7 b75.8 a66.8 a37.6 b59.0 a60.6 a0.370.230.010.61
TC, g/kg DM897.1 a853.6 b856.2 b896.8 a876.0 b875.4 b1.160.150.010.07
NFC, g/kg DM2051761732151361731.080.680.080.59
NDF, g/kg DM6246116076356366120.690.370.550.88
ADF, g/kg DM3833813843853993720.570.810.770.63
Lignin, g/kg DM6162596058750.140.220.180.76
Dry matter (DM); fresh matter (FM); organic matter (OM); crude protein (CP); total carbohydrates (TCs); non-fibrous carbohydrates (NFCs); corrected neutral detergent fiber (NDF); acid detergent fiber (ADF); standard error of mean (SEM). The values reported in this table derive from a composite sample of five plants selected from the useful rows of each plot in each harvesting cycle. Means followed by lowercase letters within a row statistically differ by Tukey’s test at the p < 0.05 significance level.
Table 3. Soluble fraction (a), potentially degradable fraction (b), degradation rate of fraction “b” (c), and non-degradable of sorghum grown in different systems (single or intercropped) fertilized with molybdenum (via leaves or soil) and non-fertilized with molybdenum.
Table 3. Soluble fraction (a), potentially degradable fraction (b), degradation rate of fraction “b” (c), and non-degradable of sorghum grown in different systems (single or intercropped) fertilized with molybdenum (via leaves or soil) and non-fertilized with molybdenum.
FractionWithout MolybdenumWith MolybdenumSEMp-Value
LeavesSoil
IntercroppedSingleIntercroppedSingleIntercroppedSingle
Soluble “a”, g/kg162.1 b146.6 b209.1 a181.3 a195.3 a198.6 a5.570.01
PD “b”, g/kg4303983944175054401.810.28
DR “c”, %/h3.02.02.03.02.02.00.310.34
ND, g/kg407.8 a454.9 a396.4 b401.3 b299.4 b361.7 b1.790.04
Potentially degradable (PD); degradation rate (DR); non-degradable (ND). Standard error of mean (SEM). The values reported in this table derive from a composite sample of five plants selected from the useful rows of each plot in each harvesting cycle. Means followed by lowercase letters within a row statistically differ by the SNK test at the p < 0.05 significance level.
Table 4. Potential degradability and effective degradability of sorghum grown in different systems (single or intercropped) fertilized with molybdenum (via leaves or soil) and non-fertilized with molybdenum.
Table 4. Potential degradability and effective degradability of sorghum grown in different systems (single or intercropped) fertilized with molybdenum (via leaves or soil) and non-fertilized with molybdenum.
Degradability (g/kg)Without MolybdenumWith MolybdenumSEMp-Value
LeavesSoil
IntercroppedSingleIntercroppedSingleIntercroppedSingle
Potential Effective380.1 b348.1 b411.6 a409.1 a404.4 a406.1 a7.590.01
k = 2%/h380.1 b348.1 b411.6 a409.1 a404.5 a406.1 a7.590.01
k = 5%/h294.7 b264.4 b327.2 a326.7 a311.0 a316.6 a7.750.02
k = 8%/h258.6 b230.1 b292.6 a289.6 a275.9 a281.4 a7.350.01
Transfer rate (k); standard error of the mean (SEM). The values reported in this table derive from a composite sample of five plants selected from the useful rows of each plot in each harvesting cycle. Means followed by lower case letters within a row statistically differ by the SNK test at the p <0.05 significance level.
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Silva, N.S.G.d.; Oliveira, A.C.d.; Júnior, B.C.; Aviz, R.O.d.; Pereira, K.P.; Vieira, D.S.M.d.M.; Costa, C.d.J.P.; Lima, J.S.d.; Henrique, J.C.G.d.S.; Souza, E.J.O.d. Can Molybdenum Fertilization Enhance Protein Content and Digestibility of Sorghum Single Cropped and Intercropped with Cowpea? Grasses 2025, 4, 28. https://doi.org/10.3390/grasses4030028

AMA Style

Silva NSGd, Oliveira ACd, Júnior BC, Aviz ROd, Pereira KP, Vieira DSMdM, Costa CdJP, Lima JSd, Henrique JCGdS, Souza EJOd. Can Molybdenum Fertilization Enhance Protein Content and Digestibility of Sorghum Single Cropped and Intercropped with Cowpea? Grasses. 2025; 4(3):28. https://doi.org/10.3390/grasses4030028

Chicago/Turabian Style

Silva, Nágila Sabrina Guedes da, Alexandre Campelo de Oliveira, Baltazar Cirino Júnior, Rhaiana Oliveira de Aviz, Kedes Paulo Pereira, Domingos Sávio Marques de Menezes Vieira, Claudenilde de Jesus Pinheiro Costa, Jucelane Salvino de Lima, Jamiles Carvalho Gonçalves de Souza Henrique, and Evaristo Jorge Oliveira de Souza. 2025. "Can Molybdenum Fertilization Enhance Protein Content and Digestibility of Sorghum Single Cropped and Intercropped with Cowpea?" Grasses 4, no. 3: 28. https://doi.org/10.3390/grasses4030028

APA Style

Silva, N. S. G. d., Oliveira, A. C. d., Júnior, B. C., Aviz, R. O. d., Pereira, K. P., Vieira, D. S. M. d. M., Costa, C. d. J. P., Lima, J. S. d., Henrique, J. C. G. d. S., & Souza, E. J. O. d. (2025). Can Molybdenum Fertilization Enhance Protein Content and Digestibility of Sorghum Single Cropped and Intercropped with Cowpea? Grasses, 4(3), 28. https://doi.org/10.3390/grasses4030028

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