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Simple Summary: Stylo silage is widely used as a protein source for ruminants in tropical and subtropical regions. High levels of biogenic amines in stylo silage are harmful to the health of ruminant animals. The purpose of this work was to evaluate the effect of formic acid and sugar on biogenic amines and amino acids concentrations and bacterial composition and fermentation profile of stylo silage. The results showed that putrescine, cadaverine, and tyramine became predominant in the control silage, and applying formic acid and sugar significantly decreased putrescine, cadaverine, tyramine, and total biogenic amine concentrations. Clostridium pabulibutyricum, Weissella cibaria and W. paramesenteroides were the predominant bacteria in the control silage, and the application of both additives remarkably lowered their relative abundance. Correlation analysis showed that C. pabulibutyricum, W. cibaria and W. paramesenteroides were positively related to putrescine, cadaverine, and tyramine formation. The application of formic acid or sugar significantly reduced the undesirable bacterial population and improved the fermentation and hygienic quality of the stylo silage. Substantial proteolysis occurs and free amino acids can be degraded to biogenic amines by decarboxylation during stylo (Stylosanthes guianensis) ensiling. High biogenic amine concentrations in silage are harmful to the health of ruminant animals. The purposes of this work were to (1) analyze the biogenic amines and amino acids concentrations, bacterial composition, and fermentation profile of spontaneously fermented stylo silage, (2) explore the effect of formic acid or sugar additive on these silage parameters, and (3) further reveal the correlations between silage amines and fermentation parameters, amino acids, and bacteria. Freshly chopped stylo was treated with distilled water (control), formic acid (4 mL/kg), and sugar (20 g/kg) and fermented for 28 days. The results indicated that putrescine (321 mg/kg dry matter), cadaverine (384 mg/kg dry matter), and tyramine (127 mg/kg dry matter) rapidly increased in concentration and become predominant in the control silage after 28 days of fermentation. Applying formic acid and sugar at ensiling, especially the acidifier, significantly decreased putrescine, cadaverine, tyramine, and total biogenic amine concentrations compared with the control treatment (p < 0.0001). Clostridium pabulibutyricum, Weissella cibaria and W. paramesenteroides were the predominant bacteria in the control silage, and the application of both additives remarkably lowered their relative abundance in comparison with the control treatment (p < 0.001). Correlation analysis showed that putrescine, cadaverine, and tyramine were positively related to pH, butyric acid, non-protein nitrogen, and ammonia nitrogen (p < 0.01). These amines also had significant correlations with C. pabulibutyricum, W. cibaria and W. paramesenteroides (p < 0.001). Putrescine, cadaverine, and tyramine were the main biogenic amines and C. pabulibutyricum was the predominant undesirable bacterium in naturally fermented stylo silage. C. pabulibutyricum, W. cibaria and W. paramesenteroides were positively related to putrescine, cadaverine, and tyramine formation. The application of formic acid or sugar significantly reduced the undesirable bacterial population and improved the fermentation and hygienic quality of the stylo silage. These findings lay the foundation for further elucidating the microbial mechanism underlying the main biogenic amine formation during fermentation of stylo silage. [ABSTRACT FROM AUTHOR]

Copyright of Journal of South China Agricultural University is the property of Gai Kan Bian Wei Hui and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

SUMMARY: Stylo (Stylosanthes guianensis) is a tropical legume known for its exceptional tolerance to low phosphate (Pi), a trait believed to be linked to its high acid phosphatase (APase) activity. Previous studies have observed genotypic variations in APase activity in stylo; however, the gene encoding the crucial APase responsible for this variation remains unidentified. In this study, transcriptomic and proteomic analyses were employed to identify eight Pi starvation‐inducible (PSI) APases belonging to the purple APase (PAP) family in the roots of stylo and seven in the leaves. Among these PSI‐PAPs, SgPAP7 exhibited a significantly positive correlation in its expression levels with the activities of both internal APase and root‐associated APase across 20 stylo genotypes under low‐Pi conditions. Furthermore, the recombinant SgPAP7 displayed high catalytic activity toward adenosine 5′‐diphosphate (ADP) and phosphoenolpyruvate (PEP) in vitro. Overexpression (OE) of SgPAP7 in Arabidopsis facilitated exogenous organic phosphorus utilization. Moreover, SgPAP7 OE lines showed lower shoot ADP and PEP levels than the wild type, implying that SgPAP7 is involved in the catabolism and recycling of endogenous ADP and PEP, which could be beneficial for plant growth in low‐Pi soils. In conclusion, SgPAP7 is a key gene with a major role in stylo adaptation to low‐Pi conditions by facilitating the utilization of both exogenous and endogenous organic phosphorus sources. It may also function as a PEP phosphatase involved in a glycolytic bypass pathway that minimizes the need for adenylates and Pi. Thus, SgPAP7 could be a promising target for improving tolerance of crops to low‐Pi availability. [ABSTRACT FROM AUTHOR]

Substantial proteolysis occurs and free amino acids can be degraded to biogenic amines by decarboxylation during stylo (Stylosanthes guianensis) ensiling. High biogenic amine concentrations in silage are harmful to the health of ruminant animals. The purposes of this work were to (1) analyze the biogenic amines and amino acids concentrations, bacterial composition, and fermentation profile of spontaneously fermented stylo silage, (2) explore the effect of formic acid or sugar additive on these silage parameters, and (3) further reveal the correlations between silage amines and fermentation parameters, amino acids, and bacteria. Freshly chopped stylo was treated with distilled water (control), formic acid (4 mL/kg), and sugar (20 g/kg) and fermented for 28 days. The results indicated that putrescine (321 mg/kg dry matter), cadaverine (384 mg/kg dry matter), and tyramine (127 mg/kg dry matter) rapidly increased in concentration and become predominant in the control silage after 28 days of fermentation. Applying formic acid and sugar at ensiling, especially the acidifier, significantly decreased putrescine, cadaverine, tyramine, and total biogenic amine concentrations compared with the control treatment (p < 0.0001). Clostridium pabulibutyricum, Weissella cibaria and W. paramesenteroides were the predominant bacteria in the control silage, and the application of both additives remarkably lowered their relative abundance in comparison with the control treatment (p < 0.001). Correlation analysis showed that putrescine, cadaverine, and tyramine were positively related to pH, butyric acid, non-protein nitrogen, and ammonia nitrogen (p < 0.01). These amines also had significant correlations with C. pabulibutyricum, W. cibaria and W. paramesenteroides (p < 0.001). Putrescine, cadaverine, and tyramine were the main biogenic amines and C. pabulibutyricum was the predominant undesirable bacterium in naturally fermented stylo silage. C. pabulibutyricum, W. cibaria and W. paramesenteroides were positively related to putrescine, cadaverine, and tyramine formation. The application of formic acid or sugar significantly reduced the undesirable bacterial population and improved the fermentation and hygienic quality of the stylo silage. These findings lay the foundation for further elucidating the microbial mechanism underlying the main biogenic amine formation during fermentation of stylo silage.

Mixed ensiling of Stylosanthes guianensis and Pennisetum sinese is an alternative method to improve the nutrient composition of feeds for healthy and green ruminant production in the tropics. This study examined the fermentation quality, nutritional composition, and microbial population in silage to select the most suitable ratio of mixed silage containing different proportions of S. guianensis and P. sinese. It was completely randomized and consisted of four treatments with five replications based on fresh weight as follows: S0, 100% P. sinese; S15, 85% P. sinese + 15% S. guianensis; S30, 70% P. sinese + 30% S. guianensis; and S45, 55% P. sinese + 45% S. guianensis. The silage samples were opened and detected after ensiling for 30 days. The results showed that the content of dry matter and crude protein in mixed silage increased with the increase in S. guianensis, while the content of acid detergent fiber decreased significantly, and the maximum or minimum value appeared in the S45 group. As the proportion of S. guianensis increased, the pH, ammonia nitrogen, and acetic acid in mixed silage gradually increased, but the lactic acid content decreased. In addition, the content of lactic acid bacteria and yeast showed a significant downward trend. Further study showed that there was a complex correlation between nutrient compositions, fermentation characteristics, and microbial numbers in mixed silage, especially dry matter, crude protein, and lactic acid bacteria. From the sensory evaluation of silage, S30 was excellent and exhibited an aromatic smell, a hazel color, and the loosest texture. However, from the results of the proportion of organic acids in mixed silage fermentation and further principal component analysis, the highest comprehensive score was in the S15 group. Considering the nutritional compositions and fermentation quality, the optimum ratio of mixed fermentation between S. guianensis and P. sinese in this experiment was 30:70. [ABSTRACT FROM AUTHOR]

Purpose: Mulching management is one of the most effective measures to alleviate soil erosion and improve soil quality in clean tillage orchards. However, the effects of mulching management patterns on carbon and nitrogen distribution have not been fully investigated, and water infiltration in the system is still unclear. This study aims to clarify the effects of mulching management on soil aggregates, carbon and nitrogen distribution, and water infiltration in subtropical clean tillage orchards in China. Methods: In this study, we focused on a typical latosol mango orchard in China subject to subtropical monsoon climate conditions. Traditional bare soil cleaning tillage management was applied to the control area, and two treatments (i.e., Stylosanthes guianensis covering and horticultural ground fabric mulching) were set up. Soil aggregates and aggregate-associated carbon and nitrogen were investigated in three soil depths (0–15 cm, 15–30 cm, and 30–45 cm). The water content was monitored in 0–100 cm soil layer. Results: Compared to clean tillage (CK), horticultural ground fabric mulching (GC) and Stylosanthes guianensis covering (SC) significantly improved the stability of soil aggregates and the proportion of > 0.25-mm water-stable aggregates in the three soil layers. And SC increased the SOC contents by 11.1% and 23.2% in the 0–15 cm and 15–30 cm soil layer while increased the TN contents by 8.3 and 24.6%, respectively. Moreover, it increased the SOC stock by 18.2% in the 15–30 cm soil layer. GC only increased 17.4% in SOC content in the 15–30 cm layer but no significant changes on SOC stocks, TN contents, and stocks in the three soil layers. However, GC is conducive to the water storage in the 0–100 cm soil layer and infiltration into the > 100 cm soil layer compared to SC. Conclusion: In conclusion, covering Stylosanthes guianensis seems to have the best enhancing effect on soil quality in subtropical orchards but restriction the water into the > 100 cm soil layer. And small macroaggregates (0.25‒2 mm) favored the enhancement of the SOC and TN contents. The findings may be useful for clean tillage orchard management in subtropical China. [ABSTRACT FROM AUTHOR]

Copyright of Acta Prataculturae Sinica is the property of Acta Prataculturae Sinica Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Key message: A highly efficient transformation procedure to generate transgenic Stylosanthes roots was established. SgEXPB1 is involved in Stylosanthes root growth under phosphorus deficiency. Stylo (Stylosanthes spp.) is an important forage legume widely applied in agricultural systems in the tropics. Due to the recalcitrance of stylo genetic transformation, functional characterization of candidate genes involved in stylo root growth is limited. This study established an efficient procedure for Agrobacterium rhizogenes-mediated transformation for generating transgenic composite plants of S. guianensis cultivar 'Reyan No. 5'. Results showed that composite stylo plants with transgenic hairy roots were efficiently generated by A. rhizogenes strains K599 and Arqual, infecting the residual hypocotyl at 1.0 cm of length below the cotyledon leaves of 9-d-old seedlings, leading to a high transformation efficiency of > 95% based on histochemical β-glucuronidase (GUS) staining. Notably, 100% of GUS staining-positive hairy roots can be achieved per composite stylo plant. Subsequently, SgEXPB1, a β-expansin gene up-regulated by phosphorus (P) deficiency in stylo roots, was successfully overexpressed in hairy roots. Analysis of hairy roots showed that root growth and P concentration in the transgenic composite plants were increased by SgEXPB1 overexpression under low-P treatment. Taken together, a highly efficient A. rhizogenes-mediated transformation procedure for generating composite stylo plants was established to study the function of SgEXPB1, revealing that this gene is involved in stylo root growth during P deficiency. [ABSTRACT FROM AUTHOR]

Phosphorus (P) is one of the principal macronutrients for plant growth and productivity. Although the phosphate (Pi) transporter (PT) of the PHT1 family has been functionally characterized as participating in Pi uptake and transport in plants, information about PT genes in stylo (Stylosanthes guianensis), an important tropical forage legume that exhibits good adaptability to low-P acid soils, is limited. In this study, stylo root growth was found to be stimulated under P deficiency. The responses of PT genes to nutrient deficiencies and their roles in Pi uptake were further investigated in stylo. Four novel PT genes were identified in stylo and designated SgPT2 to SgPT5. Like SgPT1 , which had been previously identified, all five SgPT proteins harboured the major facilitator superfamily (MFS) domain. Variations in tissue-specific expression were observed among the SgPT genes, which displayed diverse responses to deficiencies in nitrogen (N), P and potassium (K) in stylo roots. Four of the five SgPTs exhibited high levels of transcriptional responsiveness to P deficiency in roots. Furthermore, SgPT1 , a Pi-starvation-induced gene closely related to legume PT homologues that participate in Pi transport, was selected for functional analysis. SgPT1 was localized to the plasma membrane. Analysis of transgenic Arabidopsis showed that overexpression of SgPT1 led to increased Pi accumulation and promoted root growth in Arabidopsis plants. Taken together, the results of this study suggest the involvement of SgPTs in the stylo response to nutrient deprivation. SgPT1 might mediate Pi uptake in stylo, which is beneficial for root growth during P deficiency. • Five SgPTs were characterized in stylo. • SgPTs were differentially regulated by nutrient deficiencies in stylo roots. • SgPTs exhibited a high transcriptional response to P deficiency in stylo roots. • SgPT1 is a plasma membrane-localized Pi transporter. [ABSTRACT FROM AUTHOR]

Copyright of Tropical Grasslands / Forrajes Tropicales is the property of International Centre for Tropical Agriculture - CIAT and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Nutrition & Feed Technology Journal / Jurnal Ilmu Nutrisi dan Teknologi Pakan is the property of IPB University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Stylosanthes guianensis is an excellent forage legume in subtropical and tropical regions with drought tolerance, but little is known about its drought tolerance mechanism. Dehydration responsive element binding proteins (DREBs) are responsive to abiotic stresses. A SgDREB2C was cloned from S. guianensis, while SgDREB2C protein was localized at nucleus. SgDREB2C transcript was induced by dehydration treatment. Transgenic Arabidopsis overexpressing SgDREB2C showed enhanced osmotic and drought tolerance with higher levels of relative germination rate, seedlings survival rate and Fv/Fm and lower levels of ion leakage compared with WT after osmotic and drought stress treatments. In addition, higher levels of superoxide dismutase (SOD) and ascorbate peroxidase (APX) activities and stress responsive gene (COR15A, COR47) transcripts were observed in transgenic Arabidopsis than in WT under drought stress. These results suggest that SgDREB2C regulated drought tolerance, which was associated with increased SOD and APX activities and stress-responsive gene expression under drought stress. [ABSTRACT FROM AUTHOR]

Malate dehydrogenase (MDH, EC 1.1.1.37) is a key enzyme that catalyzes a reversible NAD-dependent dehydrogenase reaction from oxaloacetate (OAA) to malate. Although MDH has been documented to participate in cellular metabolism and redox homeostasis in plants, the roles of MDH members in the tropical legume Stylosanthes guianensis (stylo) remain less definitive. In this study, except SgMDH1 that had been previously characterized, six novel MDH genes were isolated from stylo and were then designated as SgMDH2 to SgMDH7. All of the SgMDH proteins possessed the common features of NAD binding, dimerization interface and substrate binding sites. Expression analysis showed that three SgMDHs exhibited preferential expressions in leaves, and one SgMDH was mainly expressed in roots. Furthermore, SgMDHs were regulated by nutrient deficiencies in stylo roots, especially for phosphorus (-P) and potassium (-K) deficiencies. Differential responses of SgMDHs to trace metal stress and heavy metal toxicity were observed in stylo roots, suggesting the involvement of SgMDHs in the response of stylo to metal stresses. The six novel SgMDHs were subsequently expressed and purified from Escherichia coli to analyze their biochemical properties. Although SgMDHs exhibited variations in subcellular localizations, each SgMDH protein displayed a high level of catalytic efficiency towards OAA and NADH but a low level of catalytic efficiency towards malate and NAD+. In addition, the activities of recombinant SgMDH proteins were pH-dependent and temperature-sensitive, and exhibited differential regulations by various metal ions. These results together suggest the potential roles of SgMDHs in stylo coping with nutrient and metal stresses. • At least seven SgMDH genes existed in stylo. • SgMDH genes were regulated by nutrient and metal stresses in stylo root. • SgMDH proteins displayed higher catalytic efficiency towards OAA than malate. • Activities of the recombinant SgMDH proteins were affected by metal ions. [ABSTRACT FROM AUTHOR]

Tropical perennial grasses are an important forage option in the frost prone, summer dominant rainfall zone in eastern Australia. These pastures commonly lack a companion legume and are, at best, irregularly fertilised with nitrogen; therefore, their production potential is not realised. We conducted a study during 2012–16 to evaluate the productivity and persistence of a range of cultivars/lines of eight tropical and two temperate perennial legumes in mixes with digit grass (Digitaria eriantha cv. Premier) at two sites (Bingara and Manilla) in the northern inland region (North-West Slopes) of New South Wales. The sites were subjected to dry conditions during the assessment period, with the Bingara site receiving <25th percentile rainfall for 2 years of the study. Lucerne (Medicago sativa) was the most productive companion legume, with mixes producing 16–18 and 38–46 t dry matter (DM)/ha at the Bingara and Manilla sites respectively. Cultivars of Desmanthus spp. were less productive, with the best performing in mixes producing 13 and 21–23 t DM/ha at Bingara and Manilla respectively. These cultivars were also persistent and readily recruited new seedlings. Their persistence was similar or superior to lucerne, which appeared to be declining, especially at the Manilla site. Mixes of burgundy bean (Macroptilium bracteatum) and digit grass produced 14–17 t DM/ha at the sites but DM tended to decline during the course of the experiment, especially at the Manilla site. Stylosanthes spp. and Chamaecrista rotundifolia had poor persistence, generally failing within 1–2 years of sowing. Therefore, we recommend lucerne and Desmanthus virgatus cvv. Marc and JCU 2 as suitable perennial legumes in mixes with digit grass during drought conditions. Tropical perennial grasses are an important forage option in the frost prone, summer dominant rainfall zone in eastern Australia, but their production potential is not realised owing to lack of nitrogen fertility. We evaluated a range of tropical and temperate perennial legume species in mixes with digit grass in the northern inland region of New South Wales over 4 years with below average rainfall. Under these conditions, lucerne and Desmanthus virgatus were the most productive and persistent species. [ABSTRACT FROM AUTHOR]

Under the condition of different phosphorus levels, the effects of phosphorus stress on the morphological indexes and biomass of Stylosanthes guianensis were studied, and the tolerance of S. guianensis to phosphorus concentration was evaluated. Using 12 different genotypes of Stylosanthes species as the material, seven phosphate fertilizer gradients were set up, 0.2, 0.1, 0.075, 0.050, 0.035, 0.02 g·kg-1, respectively, with no phosphate fertilizer as a control, and the fertilization experiment was carried out by potting method. The responses of different morphological indexes of different Stylosanthes species to different phosphorus concentrations and biomass status were compared. Designed to screen out phosphorus-efficient Stylosanthes species. The results were as follows:(1)With the increase of soil phosphorus concentration, the number of branches, plant height and stem diameter increased gradually, and root length decreased gradually, the biomasses of aboveground and underground parts increased.(2)Under the treatments of low phosphorus and high phosphorus, the aboveground biomasses of S. scabra 'Seca', S. guianensis 'COOK' were less than 9.64 g·plant-1(taking about 2/3 of the highest biomass in the test materials as the critical line), which were phosphorus-inefficient Stylosanthes species; The aboveground biomasses of S. hamataev.verano, S. guianensis 'GC1463' were higher than 9.64 g·plant-1, which were phosphorus-efficient Stylosanthes species; The aboveground biomasses of S. guianensis 'Oxley', S. guianensis TRPC90072, S. guianensis 'Graham', S. guianensis 'Endeavour', S. guianensis 'Reyan No.5', S. capitata, S. guianensis 'GC1480', S. guianensis 'GC1576' were less than 9.64 g·plant-1 under low phosphorus treatment, and the species were higher than 9.64 g·plant-1 under high phosphorus treatment and were phosphorus-sensitive Stylosanthes species. The soil phosphorus content had a great influence on the morphological indexes of Stylosanthes species, and the phosphorus-efficient Stylosanthes species had strong adaptability to the low-phosphorus soil environment. [ABSTRACT FROM AUTHOR]

Aluminum (Al) toxicity is the major constraint on plant growth and productivity in acidic soils. An adaptive mechanism to enhance Al tolerance in plants is mediated malate exudation from roots through the involvement of ALMT (Al-activated malate transporter) channels. The underlying Al tolerance mechanisms of stylo (Stylosanthes guianensis), an important tropical legume that exhibits superior Al tolerance, remain largely unknown, and knowledge of the potential contribution of ALMT genes to Al detoxification in stylo is limited. In this study, stylo root growth was inhibited by Al toxicity, accompanied by increases in malate and citrate exudation from roots. A total of 11 ALMT genes were subsequently identified in the stylo genome and named SgALMT1 to SgALMT11. Diverse responses to metal stresses were observed for these SgALMT genes in stylo roots. Among them, the expressions of 6 out of the 11 SgALMTs were upregulated by Al toxicity. SgALMT2 , a root-specific and Al-activated gene, was selected for functional characterization. Subcellular localization analysis revealed that the SgALMT2 protein is localized to the plasma membrane. The function of SgALMT2 in mediating malate release was confirmed by analysis of the malate exudation rate from transgenic composite stylo plants overexpressing SgALMT2. Furthermore, overexpression of SgALMT2 led to increased root growth in transgenic stylo plants treated with Al through decreased Al accumulation in roots. Taken together, the results of this study suggest that malate secretion mediated by SgALMT2 contributes to the ability of stylo to cope with Al toxicity. • Eleven SgALMT genes were identified in stylo. • SgALMTs exhibited various transcriptional responses to metal stresses in roots. • SgALMT2 is a plasma membrane-localized malate transporter. • SgALMT2 functions in increasing Al tolerance in stylo. [ABSTRACT FROM AUTHOR]

Stylosanthes guianensis is an excellent forage legume in subtropical and tropical regions with drought tolerance, but little is known about its drought tolerance mechanism. Dehydration responsive element binding proteins (DREBs) are responsive to abiotic stresses. A SgDREB2C was cloned from S. guianensis, while SgDREB2C protein was localized at nucleus. SgDREB2C transcript was induced by dehydration treatment. Transgenic Arabidopsis overexpressing SgDREB2C showed enhanced osmotic and drought tolerance with higher levels of relative germination rate, seedlings survival rate and Fv/Fm and lower levels of ion leakage compared with WT after osmotic and drought stress treatments. In addition, higher levels of superoxide dismutase (SOD) and ascorbate peroxidase (APX) activities and stress responsive gene (COR15A, COR47) transcripts were observed in transgenic Arabidopsis than in WT under drought stress. These results suggest that SgDREB2C regulated drought tolerance, which was associated with increased SOD and APX activities and stress-responsive gene expression under drought stress.

Tannic acid (TA), a type of polyphenol, is widely distributed in plants, especially in legumes. Not only does it possess antimicrobial properties, but it also has the ability to bind with proteins. The fermentation parameters, nitrogen fractions, antioxidant capacity, and bacterial communities present in mulberry leaves and stylo (Stylosanthes guianensis) ensiled with or without 1 and 2% TA per kilogram of fresh matter (FM) were investigated after 75 days’ fermentation. The results showed that 1 and 2% TA both significantly decreased the butyric acid content (4.39 and 7.83 g/kg dry matter (DM), respectively) to an undetectable level in both mulberry leaf and stylo silage. In addition, 2% TA significantly increased the contents of lactate (24.0–39.0 and 8.50–32.3 g/kg DM), acetate (18.0–74.5 and 9.07–53.3 g/kg DM), and the antioxidant capacity of both mulberry leaf and stylo silage, respectively. With the addition of 1 and 2% TA, the pH values (5.55–5.04 and 4.87, respectively) and ammonia-N (NH3-N) content (85.5–27.5 and 16.9 g/kg total nitrogen (TN), respectively) were all significantly decreased in stylo silage. In addition, TA increased the relative abundance of Weissella, Acinetobacter, and Kosakonia spp. and decreased that of undesirable Clostridium spp. TA can thus be used to improve the silage quality of both mulberry leaf and stylo silage, with 2% TA being the better concentration of additive to use.

Tannic acid (TA), a type of polyphenol, is widely distributed in plants, especially in legumes. Not only does it possess antimicrobial properties, but it also has the ability to bind with proteins. The fermentation parameters, nitrogen fractions, antioxidant capacity, and bacterial communities present in mulberry leaves and stylo (Stylosanthes guianensis) ensiled with or without 1 and 2% TA per kilogram of fresh matter (FM) were investigated after 75 days' fermentation. The results showed that 1 and 2% TA both significantly decreased the butyric acid content (4.39 and 7.83 g/kg dry matter (DM), respectively) to an undetectable level in both mulberry leaf and stylo silage. In addition, 2% TA significantly increased the contents of lactate (24.0–39.0 and 8.50–32.3 g/kg DM), acetate (18.0–74.5 and 9.07–53.3 g/kg DM), and the antioxidant capacity of both mulberry leaf and stylo silage, respectively. With the addition of 1 and 2% TA, the pH values (5.55–5.04 and 4.87, respectively) and ammonia-N (NH3-N) content (85.5–27.5 and 16.9 g/kg total nitrogen (TN), respectively) were all significantly decreased in stylo silage. In addition, TA increased the relative abundance of Weissella , Acinetobacter , and Kosakonia spp. and decreased that of undesirable Clostridium spp. TA can thus be used to improve the silage quality of both mulberry leaf and stylo silage, with 2% TA being the better concentration of additive to use. [ABSTRACT FROM AUTHOR]

The use of stylosanthes in mixed grass‐legume pastures may minimize the decline in forage quality and quantity that occurs in monoculture grass pastures, even though the availability of commercial cultivars in Brazil is still limited. The objective of the study was to evaluate the liveweight (LW) gain of young Nellore bulls in a mixed pasture of Brachiaria brizantha (cv. Paiaguás) with the latest release Stylosanthes guianensis cv. Bela. The study was conducted in Planaltina, FD, Brazil, from September to August in two consecutive years, right after seeding. The experimental design was a randomized complete block design with two treatments (mixed or monoculture Paiaguás pastures) and three replicates. The average daily gain (ADG) was on average greater in mixed pastures (0.436 vs. 0.350 kg head−1 day−1 in mixed and grass pastures respectively), particularly in the dry period (0.344 vs. 0.183 kg head−1 day−1). The benefit of mixed over monoculture grass pastures throughout the year was 22 kg LW/head and 55 kg LW/ha. The presence of stylosanthes increased the crude protein (CP) concentration in mixed pastures (120 g/kg) when compared to monoculture grass pastures (109 g/kg), probably influencing the ADG of bulls. The increase of liveweight gain, predominantly in the dry season, makes the high‐protein stylosanthes cv. Bela an alternative to buffer the seasonal deficit of forage quality in newly seeded grass pastures. [ABSTRACT FROM AUTHOR]

RESUMO A sustentabilidade dos sistemas conservacionistas de produção agrícola está intimamente ligada ao retorno dos nutrientes ao solo, por meio da decomposição dos resíduos vegetais. O objetivo deste estudo foi avaliar a decomposição de resíduos culturais e a mineralização de nutrientes em solos com diferentes texturas ao longo de 175 dias de incubação. Os tratamentos consistiram em fatorial 6 x 4 x 5, inicialmente composto por seis tratamentos, sendo quatro resíduos culturais: milho, braquiária, feijão, estilosantes e dois controles, ambos sem resíduo e um com adição de fontes inorgânicas dos nutrientes; quatro diferentes texturas formadas a partir de um mesmo solo e cinco tempos de avaliação após o início da incubação: 0, 25, 75, 125 e 175 dias. Utilizou-se delineamento inteiramente casualizado, com quatro repetições. Ao longo do experimento, avaliaram-se a liberação de C-CO2, taxa de decomposição e cinética de mineralização do N, P, K, Ca, Mg, S, Zn e Cu dos resíduos. A textura do solo não influenciou a liberação de C-CO2, a massa seca remanescente e a mineralização dos nutrientes dos resíduos culturais. Os resíduos de estilosantes e de braquiária apresentaram maior liberação de C-CO2 e redução de massa seca que os demais resíduos. A mineralização do N, P e S ocorreu de forma inversa às relações C/N, C/P e C/S. A decomposição dos resíduos culturais foi regulada pelos teores de N e extrativos solúveis em água; e a mineralização de macronutrientes, pelos seus respectivos conteúdos iniciais nos resíduos.

Gradual reduction of legumes in mixed tropical pastures requires periodic oversowing. Exploiting the carrying capacity of grass for an extra year after the disappearance of legumes can be economically advantageous to the farmer. This study aimed to evaluate the productivity of Xaraés palisadegrass (Brachiaria brizantha) pastures in response to its historical association with stylo (Stylosanthes guianensis) under two canopy heights to determine whether different grazing management conditions affect the defoliation pattern left by grazing animals. The split-plot experimental design was used, with the historical botanical composition (HBC) (24, 34, 45 and 52 % legume composition) corresponding to the main plots and the canopy frequency of defoliation determined at heights of 30 and 45 cm for Xaraés palisadegrass corresponding to the subplots with two replicates (500 m2) grazed by Tabapuã cows. Pastures with over 34 % stylo in the botanical composition remained productive for one year after legume disappearance, accumulating more than 8 mg ha−1 of forage per year. Xaraés palisadegrass pastures at a height of 30 cm provided better canopy structure, with 64 % less stem production and 43 % less dead material. The 30-cm pre-grazing canopy height provided a grazing environment conducive to forage intake by animals that resulted in efficient use of the pasture. In response to the improved canopy structure, the cows grazed an average of 60 fewer minutes. A HBC greater than 34 % of legumes in the pastures allows for the postponement of legume oversowing until the next growing season.

Organic amendments can reportedly sustain and increase lowland rice productivity in smallholder systems. Few studies have assessed locally-available substrates in hydrologically variable floodplain environments. We investigated the effects of green and farmyard manures on rice yields, and total soil C and N in the Kilombero floodplain, Tanzania. At both the fringe and the middle positions, five treatments were applied in 2016 and 2017, comprising (1) non-amended control, (2) farmyard manure, (3) pre-rice legumes, (4) post-rice legumes and (5) a combination of green and farmyard manures. Residual treatment effects were assessed in 2018 when rice plots were uniformly non-amended. Depending on the year and the position, organic amendments increased rice grain yields by 0.7–3.1 Mg ha–1 above the non-amended control. Sole green and farmyard manure applications had similar effects on grain yield, while a combination of green and farmyard manure led to a significant increase in grain yield above both the control and sole applications of organic amendments in both years. The contribution from biological N2 fixation by legumes ranged from 4 to 61 kg N ha–1. Despite partial N balances being mostly negative, we observed positive residual effects on the yield of the non-amended rice in the third year. Such effects reached up to 4 Mg ha−1 and were largest with post-rice legumes, sole or combined with farmyard manure. Irrespective of the position in the floodplain, manures significantly increased soil C and N contents after two years, hence enhancing soil fertility and resulting in increased rice grain yields. Comparable benefits may be obtained along the hydrological gradients of other large river floodplains of the region and beyond.

Grazing ruminants are faced with the dilemma of making decisions when searching for and defoliating forage to meet their nutrient requirements, particularly in situations of heterogeneity in forage abundance and sward height. Knowledge of sward-animal interaction at bite level is essential for animal intake, performance and productivity of grazing systems. Here, we investigated the effect of two spatial distributions of forage biomass (dense and sparse) assigned to main plot, and three sward heights (10, 15 and 20 cm) allotted to sub-plot in a split plot design, with three replicates totalling six treatments, aimed at assessing the biting rate of White Fulani (WF) calves. The study was carried out between November and December 2015. Biting rate was recorded with the aid of a Chloride UK 8 channel, H.264 digital video recorder and Chloride UK IR waterproof camera equipped with 3.6 mm lens. WF calves altered their biting rate in an attempt to meet their intake requirement on Panicum maximum/Stylosanthes guianensis sward, notably with decrease in bite number as access time advanced. The calves, grazing pasture with dense biomass, recorded higher bite number during the occupation time (p < 0.05). Measurement of grazing bites of WF calves indicates that the herbage could be defoliated by ruminants on tropical pasture relatively easily. [ABSTRACT FROM AUTHOR]

Performance of Three Varieties of Cassava (Manihot esculenta Crantz) Grown in Association with Stylosanthes guianensis (Aublet) Swartz in the Conditions of the Batéké Plateau (City-Province of Kinshasa, DRC). In order to develop a system of direct seeding in a permanent vegetative cover of Stylosanthes guianensis (Aublet) Swartz adapted to the growing conditions of the Batéké plateau, the behavior of improved cassava varieties ZIZILA, TME 419 and BUTAMU was evaluated in sole cropping and in intercropping with Stylo. The trial was conducted from October 2009 to August 2011 in two sites representative of the soil diversity on the plateau. The results demonstrate the existence of a strong competition between the associated crops during the 1st year of cultivation. Yield losses recorded compared to situations of sole cropping ranged on average between 22,6-35% for the biomass of Stylo cut at 8 months in the two trial sites, and amounted to about 50% for cassava harvested at 12 months. Delaying the harvest of cassava to 16 months, with a cutting of the Stylo canopy to form a mulch at the end of the long dry season (8 months after planting), has permitted cassava to reach yields equivalent to the situation of sole cropping. The average yields of fresh cassava roots were significantly lower in the site of Neema (9.7 t.ha-1 at 12 months in sole cropping) compared to those recorded in the site of The Way (12.8 t.ha-1 at 12 months in sole cropping). In each site, no significant difference could be detected for the yields of the compared cassava clones cultivated in pure stand. When harvesting cassava at 12 months, the production of Stylo dry biomass was equivalent at 20 months regardless of the installation mode (sole cropping or intercropping with cassava). The trial did not permit to clearly separate the cassava varieties for their intercropping ability with Stylo. The intercropping of Stylo with cassava is a cost effective method to install a permanent cover in which it is possible to make direct seeding of other crops.

Family farms in the tropics mainly rely on rainfed agriculture. Water availability is limited to rainfall and is one of the main constraints to crop productivity. Conservation agriculture (CA) is promoted as an alternative that, among other functions, enhances water infiltration and limits evaporation from the soil thanks to a mulch of crop residues left on the soil surface. These functions are assumed to reduce the water availability constraint by limiting water stress during crop growth. But the variability of rainfall distribution combined with the wide range of agroecological conditions and the variety of crop husbandries in the tropics makes it difficult to evaluate the efficiency of mulching. The aim of this study was to capture the variability through a simple modeling approach using the crop growth model PYE-CA, which requires a limited set of parameters and a virtual experiment (VE). We applied our approach to a case study of upland rice in the Lake Alaotra region in Madagascar, where rainfall distribution is highly variable. The VE used a 17-year series of weather data with a range of soil water conditions, sowing dates, and growth and yield limitations that cover the variability of agroecological conditions and management systems in the study area. The VE revealed that variable successions of wet and dry episodes during the rainy season resulted in both water stress and an increase in deep drainage. In the majority of conditions simulated, enhancing water infiltration through CA mainly increased water loss through drainage. However, better water infiltration may also reduce the production risks involved in early sowing or crop intensification, thereby offering new opportunities to farmers. As an alternative to time consuming and labor intensive experimentation, we propose a suitable modeling approach to identify the main drivers of rainfall × crop interactions that could be extrapolated to other regions in the tropics. [ABSTRACT FROM AUTHOR]

The objective of this study was to investigate the behaviour of White Fulani (WF) yearling calves grazing a Panicum maximum/Stylosanthes guianensis mixture under traditional management system in south western Nigeria. The effects of two biomass spatial distribution (dense and sparse) were evaluated in association with three pasture heights (10, 15 and 20 cm), with calves allowed access to the pasture for 2:00 h. The experiment was laid out in a split plot design with the two biomass spatial distribution assigned to the main plot and sward height assigned to the sub plot to give six treatments; this was replicated three times. The experiment took place from November to December, 2015. Grazing behaviour was recorded with the aid of a Chloride UK 8 channel, H.264 digital video recorder and Chloride UK IR waterproof camera fitted with 3.6 mm lens. Data on grazing time, walking time, idling/resting/rumination time and time spent by the animals exhibiting self-licking behavior were collected from the recorded CCTV video player. There was a significant difference in the time spent grazing by the calves with those grazing the pasture with dense biomass at 15 cm height recording more grazing time (87.33 min). Animals on the pasture with sparse biomass at 10 cm height recorded more (p < 0.05) idling/resting/rumination time (18.33 min). The time spent by the calves walking was similar for the pasture with dense biomass at 10 cm and 15 cm above the ground. Self-licking behaviour was generally exhibited by the calves across the treatments. However, calves grazing in the plot with sparse biomass at 20 cm height engaged in more self-licking behaviour than those in the dense biomass pasture. The differences observed in the behavioural parameters examined clearly indicated the capability of WF yearling calves to increase grazing time, reduce the time spent walking, idling/resting/rumination and self-licking time, thereby improving their efficiency of grazing. From management perspective, plots with dense pasture biomass cut to 15cm height is suggested for optimal production of grazing calves on sown Panicum / Stylosanthes mixture under the present production systems in south western Nigeria. [ABSTRACT FROM AUTHOR]

Performance Assessment of the Production of Seeds by Manual Sieving of the Soil of Three Varieties of Stylosanthes guianensis (Aublet) Swartz under the Conditions of the Batéké Plateau (DRC). In manual agriculture with low resources level, Stylosanthes guianensis is one of the most interesting cover crop for developing direct seeding mulch-based cropping systems. To promote its cultivation in the DRC, the performances of a seed production method by sieving of the soil were evaluated for three varieties of Stylo (a local ecotype, CIAT 184 variety, and 202cc variety) in two sites of the Batéké plateau characterized by contrasted fertility levels. The results obtained demonstrate the interest of the seed multiplication method tested, both in quantities and quality of the produced seeds. The production cost of one kg of seeds varies with the soil fertility, the planting date, and the cultivar. Among the three compared varieties, CIAT 184 variety produced the highest quantity of seeds. If sown at the beginning of the long rainy season, after a long fallow, in one of the most fertile soils of the plateau, this cultivar can produce 600 kg ha-1 seed in the first year of cultivation with a production cost of USD 1.31 kg-1, equivalent to less than 0.5 man.day.kg-1.

El efecto de edad de rebrote (21, 42, 63 y 84 días) sobre el rendimiento de materia seca (RMS), proporción de hoja (PH) y valor nutritivo de cacahuatillo (Arachis pintoi), stylo (Stylosanthes guianensis), clitoria (Clitoria ternatea) y kudzú (Pueraria phaseoloides), se evaluó durante la época seca (marzo-mayo) y lluviosa (junio-agosto) de 2013. El RMS y la fibra detergente neutro (FDN) se incrementaron con la edad, mientras que la PH, proteína (CP) y degradabilidad disminuyeron. Cacahuatillo y stylo registraron los RMS más altos en las dos épocas; en promedio 5.5 y 7.5 t ha-1 a los 84 días en época seca y lluviosa, respectivamente. En ambas épocas, la mayor y menor PH fueron para cacahuatillo y stylo, respectivamente. En CP, clitoria y cacahuatillo presentaron las mayores en ambas épocas; superiores a 140 g kg-1 MS aún a 84 días de edad. No se observó variación significativa en CP a partir de los 42 días en las especies. A los 21 días, stylo (704.7 g kg-1 MS) en la época seca y kudzú (658.4 g kg-1 MS) en la época lluviosa presentaron la mayor FDN. No hubo diferencias entre especies a partir de los 42 días. Cacahuatillo tuvo la mayor degradabilidad (>700 g kg-1 MS) durante su crecimiento en ambas épocas. En clitoria, stylo y kudzú sólo fue superior a 700 g kg-1 MS a los 21 días, pero desde los 42 días de edad, la degradabilidad disminuyó. En conclusión, la edad de rebrote que integra mayor RMS y valor nutritivo es la de 42 días en las leguminosas evaluadas, independientemente de la época del año.

Objetivou-se avaliar o efeito da aplicação de fósforo na implantação de estilosantes Mineirão em consórcio com capim-xaraés. O experimento foi instalado em uma área de 8.000 m², dividida em 24 parcelas experimentais de 333,3 m². As doses de fósforo utilizadas no estabelecimento da pastagem foram 25, 50, 100 e 200 kg/ha de P2O5. As avaliações foram feitas aos 65 dias após a semeadura. Utilizou-se o delineamento em blocos casualizados com três repetições e duas repetições do tratamento dentro de cada bloco. As maiores taxas de aumento no comprimento da lâmina foliar e perfilhamento do capim-xaraés, comprimento de folíolo, largura de folíolo e altura do estilosantes Mineirão foram observadas com a aplicação de 25 a 50 kg/ha de P2O5. As maiores taxas de aumento na largura da lâmina foliar e altura de perfilho do capim-xaraés foram obtidas com aplicação de 25 a 100 kg/ha de P2O5. O número de plantas de estilosantes Mineirão foi maior com a aplicação de 44 kg/ha de P2O5 e reduziu de forma acentuada com o aumento da adubação fosfatada. A adubação fosfatada de estabelecimento de 44 kg/ha de P2O5 garante maior população inicial de plantas de estilosantes Mineirão em consórcio com o capim-xaraés. Todavia, mais estudos são necessários para se verificar o grau de compatibilidade entre as duas espécies e a viabilidade da consorciação. A aplicação de doses crescentes de fósforo em consórcio proporciona aumento nas taxas de acúmulo de matéria seca do capim-xaraés e de acúmulo de matéria seca total durante o primeiro período seco pós-estabelecimento da pastagem.The objective of this study was to evaluate the effect of the application of phosphorus on the establishment of Stylosanthes guianensis cv. Mineirão and Brachiaria brizantha cv. Xaraés mixed. The experiment was installed in an area of 8,000 m², divided into 24 plots of 333.3 m². The phosphorus doses utilized in the establishment of pasture were 25, 50, 100 and 200 kg/ha of P2O5. The evaluations were made 65 days after sowing. The experimental design was a randomized blocks design with three replications and the treatment with two replicates per block. The highest rates of increase in the length of the leaf blade and tillering of Xaraés grass, leaflet length, leaflet width and height of the legume occurred from 25 to 50 kg/ha of P2O5. The highest rates of increase in the width of the leaf blade and tiller height of Xaraés grass occurred from 25 to 100 kg/ha of P2O5. Number of plants of Mineirão stylo was higher with fertilization with 44 kg/ha of P2O5 and decreased drastically with phosphate. Phosphate fertilizers establishing 44 kg/ha P2O5 provide better establishment of the intercropped pasture. Nevertheless, further studies are required to determine the degree of compatibility between the two species and the viability of intercropping. Application of growing levels of phosphorus in an intercropping system provides increase in the rates of accumulation of dry matter of Xaraés grass and accumulation of total dry matter during the first dry period post-establishment of the pasture.

Objetivou-se, com este trabalho, avaliar o efeito do uso de dois corretivos de acidez do solo e de doses crescentes de fósforo, sobre a nodulação, produção de matéria seca, acúmulos e teores dos nutrientes nas raízes do estilosantes Mineirão (Stylosanthes guianensis (Aubl.) Sw. cv. Mineirão). O experimento foi conduzido em casa-de-vegetação com delineamento experimental em blocos casualizados, com três repetições. Os tratamentos foram dispostos em esquema fatorial 5x2, constituído por cinco doses de P (50, 100, 200, 400 e 800 mg dm-3 de solo) e dois tipos de corretivo (calcário dolomítico e silicato de Ca e Mg). A produção de matéria seca de raízes, a nodulação e o acúmulo dos nutrientes P, N, Ca e Zn foram maiores quando a adubação esteve associada ao silicato. Entretanto, a aplicação de doses superiores a 257 mg dm-3 de P na presença de silicato, inibiu o desenvolvimento do sistema radicular do Mineirão, provavelmente por causa de uma interação negativa entre os nutrientes P e Zn, causada pela alta disponibilidade de P.The objective of this research was to evaluate the effect of two soil correctives and P rates on nodulation, dry matter production, accumulation and content of nutrients in the roots of Stylosanthes guianensis (Aubl.) Sw. cv. Mineirão. The experiment was performed in a greenhouse. A randomized blocks design was used in a 5x2 factorial arrangement, with five P rates (50, 100, 200, 400 and 800 mg dm-3 soil) and two soil correctives (lime and silicate) with three replicates. The dry matter production of roots, nodulation and nutrient accumulation of P, N, Ca and Zn increased with the association between fertilizer and silicate. However, the application of P higher than 257 mg dm-3 in the presence of silicate, inhibit the development of the root system of Mineirão, probably due to a negative interaction between Zn and P nutrients, caused by the high availability of P.

The effect of arbuscular mycorrhizal inoculation on critical levels of phosphorus in the soil for Neonotonia wightii and Stylosanthes guianensis was evaluated. An amount of 20 places were selected, with concentrations of assimilable phosphorus from 0 to 20 cm, which varied from 9 to 55 mg kg-1. In each place, the response of both legumes to phosphoric fertilization was evaluated with or without inoculation of the arbuscular mycorrhizal fungi Glomus cubense. Using the method of Cate and Nelson, critical levels of phosphorus in the soil were obtained for these legumes, inoculated or not. For N. wightti without inoculation, the critical level was 35 mg kg-1(R2=0.90), but with the inoculation with G. cubense, it decreased up to 20 mg kg-1 (R2=0.87). For S. guianensis, without inoculation, the result was 20 mg kg-1 (R2=0.83). In presence of G. cubense, there was no response to phosphoric fertilization. [ABSTRACT FROM AUTHOR]

Fabaceae are an option to increase the availability of protein in the prairies, but species of the Fabaceae family contain phenolic compounds, which depending on their number and type, benefit or harm livestock production. The aim of the study was to determine the concentration of phenolic regrowth compounds of different ages of Arachis pintoi, Stylosanthes guianensis, Clitoria ternatea and Pueraria phaseoloides. The study was carried out in an experimental field, INIFAP-Tabasco, Mexico, from March to August 2013, covering the dry and rainy seasons, and in four ages of regrowth after uniformity cutting: 21, 42, 63 and 84 d. The variables evaluated were the concentrations of five types of phenolic compounds: total polyphenols (PFT), no tannins (FNT), condensed tannins (TC) hydrolysable (TH) and total tannins (TT). Sixteen treatments were evaluated in a design of completely randomly divided plots with three replications, the species as main plot, and regrowth age as a minor plot. Comparisons between means were performed using the Tukey test (p£0.05). We observed the interaction species x age of regrowth in the five types of compounds. The highest concentrations of phenolic compounds (CF) were obtained in all species at 42 d of regrowth. Clitoria ternatea presents the highest concentrations in the months without rain (155.4, 40.1, 16.9, 98.4 and 115.3 g kg-1 MS of PFT, FNT, TC and TH) and rainy (121.7, 39.6, 20.1, 61.9 and 82.0 g kg-1 MS of PFT, FNT, TC and TH). In contrast, S. guianensis presented lower concentrations of CF. The TC concentration varied between species, in the months without rain from 4.62 (Stylo) to 20.21 (Kudzú) g kg-1 MS and in rainy months from 3.66 (Stylo) to 20.10 (Clitoria) g kg-1 MS. No species reached the toxic level of 60 g kg-1 MS of TC. Results showed that the concentration of CT varied among species and age of regrowth. Among species, the highest concentrations were observed in C. ternatea and the lowest in S. guianensis. The interaction species-regrowth age determined the concentration of phenolic compounds. [ABSTRACT FROM AUTHOR]

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O objetivo deste trabalho foi avaliar a disponibilidade de forragem, a composição bromatológica, o consumo de matéria seca e a proporção de gramínea e leguminosa na dieta de vacas mestiças Holandês x Zebu, em pastagem consorciada de Brachiaria decumbens cv. Basilisk, Stylosanthes guianensis var. vulgaris cv. Mineirão e leguminosas arbóreas. Para estimativa da produção fecal, foram usados 10 g vaca-1 dia-1 de óxido crômico, durante dez dias. Amostras de extrusa foram usadas para determinação da composição bromatológica e digestibilidade in vitro da matéria seca. A disponibilidade de matéria seca de forragem de B. decumbens variou com as condições climáticas, enquanto a de S. guianensis decresceu linearmente ao longo do período experimental. O consumo de matéria seca foi maior em maio de 2001 (1,9% do peso do animal vivo) e não diferiu entre os demais meses (1,5% do peso do animal vivo). Os baixos índices de consumo de matéria seca refletiram altos teores de fibra em detergente neutro (70,2% a 79,4%) e baixos coeficientes de digestibilidade in vitro de matéria seca (42,1% a 48,0%) da forragem. O consumo de leguminosa variou entre 8,7% e 24,1% do total ingerido. O consumo de matéria seca esteve diretamente relacionado à porcentagem de leguminosa na pastagem, o que evidencia o potencial de uso de pastagens consorciadas para vacas leiteiras.The objective of this work was to evaluate the herbage availability, nutritive value, dry matter intake and grass and legume percentage in diet of crossbred Holstein-Zebu cows, in pasture with Brachiaria decumbens cv. Basilisk, Stylosanthes guianensis var. vulgaris cv. Mineirão and tree legumes. To estimate the fecal output, it was used 10 g cow-1 day-1 of chromium oxide during ten consecutive days. Extrusa samples were used to determine the chemical composition and in vitro dry matter digestibility. B. decumbens availability varied with climatic conditions, while S. guianensis availability decreased linearly along the experimental period. Dry matter intake was higher in May/2001 (1.9% body weight) and did not differ among other months (1.5% body weight). Low dry matter intake values were related to low in vitro dry matter digestibility coefficients (42.1% to 48.0%) and high neutral detergent fiber content (70.2% to 79.4%). Dry matter intake was directly related to legume percentage in the pasture. This observation could indicate the potential of mixed pasture for improving nutritive value in dairy cattle diet.

Um experimento foi conduzido com objetivo de avaliar a produtividade e qualidade do capim-braquiária (Brachiaria decumbens Stapf. cv. Basilisk) e do capim-jaraguá (Hyparrhenia rufa (Ness) Stapf.) adubados com nitrogênio (N) ou em consórcios com estilosantes (Stylosanthes guianensis (Aubl.) Swartz cv. Mineirão), introduzidos em uma pastagem degradada. Foram avaliadas duas gramíneas (capim-braquiária e capim-jaraguá), quatro doses de N (0, 50, 100 e 150 kg/ha) e dois tratamentos referentes aos consórcios capim-braquiária + estilosantes e capim-jaraguá + estilosantes. Após estabelecimento das forrageiras, foram realizadas duas avaliações (colheitas). As produções de matéria seca (MS) do capim-braquiária aumentaram de 1.824 para 4.604 kg/ha e de 1.019 para 2.149 kg/ha nas duas colheitas, respectivamente, quando as doses de N extremas foram comparadas, porém não houve resposta do capim-jaraguá. O teor de proteína bruta (PB) do capim-braquiária elevou de 3,18 para 5,68 dag/kg apenas na primeira colheita, enquanto o capim-jaraguá apresentou incremento de 2,53 para 3,72 dag/kg e de 7,32 para 8,45 dag/kg, respectivamente, em ambas as colheitas, quando comparadas às doses extremas. Os teores de fibra em detergente neutro (FDN) e fibra em detergente ácido das gramíneas não foram influenciados pela aplicação de N. Em ambas as colheitas, ao se elevarem as doses de N, houve diminuição dos teores de P nas duas gramíneas e de K no capim-braquiária. Os teores de Ca e Mg das gramíneas, em sua maioria, não foram influenciados pelo N, em ambas as colheitas. As produções médias de MS dos dois consórcios foram superiores às produções médias das duas gramíneas adubadas, com incrementos de 42,62 e 15,00% no rendimento forrageiro, na primeira e segunda colheitas, respectivamente. As forrageiras em consórcios, de forma geral, apresentaram teores de PB e Ca mais elevados e de FDN mais baixos que as gramíneas puras adubadas com N, melhorando a qualidade do pasto.This study was carried out to evaluate the productivity and quality of either Brachiaria decumbens Stapf. cv. Basilisk and Hyparrhenia rufa (Ness) Stapf. grasses fertilized with nitrogen (N) or mixed with stylosanthes (Stylosanthes guianensis (Aubl.) Swartz cv. Mineirão), introduced into a degraded pasture. Both grasses were evaluated, as well as four doses of nitrogen (0, 50, 100 and 150 kg/ha) and two treatments that consisted of mixing B. decumbens and S. guianensis as well as H. rufa and S. guianensis. After forages were established, two evaluations were also performed (harvests). The dry matter (DM) yields of B. decumbens increased from 1,824 up to 4,604 kg/ha and from 1,019 to 2,149 kg/ha in both respective harvests, when the extreme N doses were compared, but H. rufa showed no response. The crude protein (CP) content in B. decumbens increased from 3.18 up to 5.68 dag/kg at the first harvest only, whereas H. rufa showed an increment from 2.53 to 3.72 dag/kg and from 7.32 to 8.45 dag/kg in both respective harvests, compared to the extreme doses. The contents of both neutral detergent fiber (NDF) and acid detergent fiber in the grasses were not affected by N application. When N doses increased, the P contents in both grasses and K contents in B. decumbens were reduced at both harvests. Most contents of Ca and Mg in grasses were not affected by N at both harvests. The average DM yields of both mixtures were superior to the average yields of both fertilized grasses, as showing increments of 42.62% and 15.00% in forage yield at the first and second harvests, respectively. In general, the mixed forages showed higher contents of CP and Ca, but lower NDF values than those N-fertilized pure grasses, therefore improving the quality of the pasture.

O objetivo deste trabalho foi avaliar a massa de forragem e a composição botânica de pastagens de Brachiaria decumbens Stapf em monocultivo e consorciada com Stylosanthes guianensis (Aubl.) Sw. var. vulgaris cv. Mineirão, em diferentes meses do ano. As amostras obtidas em janeiro e maio foram submetidas a ensaio de degradabilidade in situ da matéria seca. Foram utilizados três piquetes (repetições), cada um dividido em duas parcelas (monocultura e consorciação). Após cada amostragem, o pasto foi submetido a pastejo com vacas secas. A massa de forragem de B. decumbens não variou com o sistema de cultivo; foi menor no mês de outubro (291 kg/ha) e não diferiu entre os demais meses (1.571 kg/ha). A massa de forragem da leguminosa decresceu ao longo do ano e sua porcentagem na pastagem foi maior em outubro/2001 e menor em janeiro/2002. A massa de forragem total na pastagem consorciada (2.158 kg/ha) foi maior que a do monocultivo (1.481 kg/ha). A taxa de degradação e a degradabilidade efetiva média de S. guianensis foram, respectivamente, de 6,8%/h e 61,5%, e de B. decumbens foram de 5,3%/h e 49,2%. A leguminosa contribui no aumento da quantidade e na melhoria da qualidade da forragem disponível na pastagem.

El objetivo fue evaluar la respuesta sobre el rendimiento de MS de Stylosanthes guianensis a una baja dosis de fósforo. El diseño experimental fue bloques completos al azar, con cuatro repeticiones. Los tratamientos fueron PO y P 11kg ha, usando superfosfato triple, aplicado al voleo e incorporado en el momento de la siembra. El suelo pertenece a la Serie Ensenada Grande, clasificado como psamaquent típico. Las semillas se escarificaron, se inocularon y se sembró a una densidad de 3 kg ha. Se evaluó vigor de plantas, porcentaje de cobertura, rendimiento mensual y porcentaje de materia seca (MS). Se determinó rendimiento acumulado, contenido de P, K y proteína cruda. Los datos se analizaron con varianza y las diferencias entre medias con Tukey (p< 0,05). Los valores de cobertura fueron superiores en las parcelas fertilizadas (74% vs. 45%). El porcentaje de MS fue menor en las plantas fertilizadas (21,8% vs. 24,6%). El fósforo incrementó en un 100% la producción acumulada, siendo las diferencias estadísticamente significativas (p< 0,05). Los contenidos de P fueron diferentes entre los tratamientos. En un suelo arenoso con muy baja disponibilidad de P, una dosis baja de P permitió incrementar el rendimiento de MS y el contenido de P en planta en esta especie