Pre-sprouted Seedlings Research Articles

Root- and foliar-applied silicon modifies C: N: P ratio and increases the nutritional efficiency of pre-sprouted sugarcane seedlings under water deficit.

Water deficit limits the establishment of sugarcane plants from pre-sprouted seedlings (PSS). Silicon (Si) can mitigate such stress, and your supply in plants with the active absorption mechanism is carried out through roots. However, foliar spraying has been practiced to supply Si in PSS production nurseries. Althought it is known that Si via roots can alter C: N: P ratios, nothing has been reported about its supply via foliar spraying, nor whether such changes interfere with structural nutrient use efficiency and with plant physiological responses. Thus, this study aimes to asses whether Si foliar spraying changes C: N: P ratios and increases the nutritional efficiency of PSS, as well as whether water deficiency interferes with such a relationships. For these purposes, three experiments were carried out. In experiment I, treatments consisted of two sugarcane cultivars (CTC 4 and RB 966928) and three Si supply forms (in nutrient solution via roots [SiR], via foliar spraying [SiL], and one control with the absence of Si [-Si]). The same Si supply forms were used in the other two experiments. In experiment II, a short-term water deficit was induced by polyethylene glycol addition to nutrient solution (-0.6 MPa) for three days. In experiment III, a long-term water deficit was imposed using levels of soil water retention capacity (70% [no water deficit], 50% [moderate water deficit], and 30% [severe water deficit] for 30 days. Our findings revealed that Si supply decreased C concentrations regardless of water conditions and that N and P concentrations varied with Si supply form and water deficit level. Moreover, root- and foliar-applied Si modified the C: N: P stoichiometry and increased C use efficiency in PSS, which thus increased N and P use efficiencies. Such an increased nutritional performance helped adjust physiological parameters and increase dry matter yield in PSS, both under water stress and non-stress conditions. Further, Si foliar spraying promoted structural effects on PSS regardless of water conditions, even if sugarcane has an active absorption via roots. In conclusion, foliar spraying can be used to supply Si in PSS production nurseries.

BIOCARVÃO COMO ATENUANTE DA FITOTOXICIDADE DE HERBICIDAS EM MUDAS PRÉ-BROTADAS DE CANA-DEAÇÚCAR

O objetivo deste trabalho foi avaliar o efeito do biocarvão na sensibilidade de mudas pré-brotadas (MPB) ao clomazone, imazapic e indaziflam aplicados em pré-plantioisoladamente ou em associação. Foram avaliadas duas variedades de cana-de-açúcar (RB975952 e RB 985476). O delineamento experimental foi inteiramente casualizado com 4repetições, em esquema fatorial 9 x 2, sendo nove tratamentos (imazapic 52,5 e 200 g i.a. ha-1, clomazone 1000 g i.a. ha-1, indaziflam 100 g i.a. ha-1 e associações de imazapic +clomazone (52,5 + 600; 52,5 + 1000; 200 + 600 e 200 + 1000 g i.a. ha-1 e testemunha) e apresença ou ausência do biocarvão no sulco de plantio. A RB 985476 apresentousensibilidade aos herbicidas clomazone e imazapic. A toxicidade provocada pelosherbicidas imazapic + clomazone diminiu pelo efeito do biocarvão. Para o imazapic nãohouve efeito do biocarvão na redução da fitotoxicidade. Em relação a RB 975952 foiverificada sensibilidade ao clomazone + imazapic e clomazone isolado, sendo o biocarvãoeficaz na redução da fitotoxicidade. O indaziflam foi seletivo para as duas variedades. Podese concluir que o biocarvão atuou de forma efetiva para clomazone isolado ou emassociação com o imazapic, sendo pouco efetivo para o herbicida imazapic isolado.

Fertilizer Recommendations for Sugarcane Pre-sprouted Seedling Production in Ebb-and-Flow Subirrigation Benches

Ebb-and-flow subirrigation can save water and nutrients by reusing fertilizer solution (FS). Since there is no leaching and salts tend to accumulate over time in the growing media, nutrient concentrations should be lower than applied by other irrigation systems. However, fertilizer requirements for subirrigated sugarcane (Saccharum species hybrid) pre-sprouted seedlings (SPSS) are not yet available. Our objective was to evaluate two FS concentrations to produce SPSS in an ebb-and-flow system: 33% and 67% of the recommended concentrations for seedlings produced using overhead irrigation. We tested three cultivars (IACSP95-5000, IACSP95-5094 and IAC91-1099) in terms of crop growth and macronutrient content of stems and leaves. There was no effect of FS concentrations on 1st ligule height, diameter, and dry weight. Irrigation with both FS concentrations resulted in seedlings with adequate nutritional status. Substrate electrical conductivity (EC) increased for treatment irrigated with FS 67%, indicating excessive fertilization. For FS 33%, substrate EC remained stable. FS with concentration of 33% can be used to produce SPSS in ebb-and-flow benches, resulting in adequate plant growth and fertilizer savings.

Nitrogênio e Azospirillum brasilense no desenvolvimento inicial da cana-de-açúcar

A study was conducted with the objective of investigating the effects of the interaction between the inoculation of the pre-sprouted seedlings with Azospirillum brasilenseand the nitrogen fertilization in topdressing on the development of sugarcane plants(Saccharum officinarum). Pre-sprouted sugarcane seedlings, produced from 3.0 cm long mini-stems of the RB867515 variety, were transplanted 25 days after sprouting into 12 L plastic pots. The treatments were arranged in a randomized block design, in a 2 × 5 factorial scheme: two inoculation treatments [without (control) and inoculation with Azospirillum brasilense] and five application rates of N fertilizer in topdressing (0, 30, 60, 90 and 120 mg dm–3of N), with four repetitions. The inoculation with A. brasilensewas carried out in transplanting the seedlings using 4 mL of the inoculum AzoTotal® per seedling, containing the strains AbV5 and AbV6. The nitrogen fertilization in topdressing was performed at 20 days after transplanting the seedlings as urea (45% of N). The results reported that the application of N fertilizer rates in topdressingresulted in a linear increase in plant height, stem diameter, number of leaves per plant, number of tillers and dry matter production of plants inoculated with A. brasilense.When the plants were not inoculated with A. brasilense, nitrogen fertilization resulted in an increase also in the number of leaves and tillers per plant. The use of A. brasilenseinoculation in pre-sprouted sugarcane seedlings has a beneficial effect on the development of plants only when associated with nitrogen fertilization in topdressing. Sugarcane plants not fertilized with N have a negative response to inoculation with A. brasilense, indicating the occurrence of possible phytotoxic effects on plant development up to 60 days after transplanting.

Response of Pre-sprouted Sugarcane Seedlings to Foliar Spraying of Potassium Silicate, Sodium and Potassium Silicate, Nanosilica and Monosilicic Acid

Silicon (Si) applied via foliar on pre-sprouted sugarcane seedlings is a practical alternative for supplying Si, however, it is necessary to use an adequate Si source and optimal concentration, but this information is unknown. This study evaluates the effect of alternative Si sources applied via foliar spraying at lower concentrations in relation to potassium silicate, on Si accumulation and the beneficial effects on pre-sprouted sugarcane seedlings and initial growth. Two experiments were carried out in a greenhouse, one in the production phase of pre-sprouted seedlings and the other in the initial growth phase of sugarcane grown in pots. Both experimental designs were randomized blocks with treatments arranged in a 4 × 5 factorial scheme, with four Si sources: nanosilica (Si-nano), monosilicic acid stabilized with PEG-400 (Si-acid), sodium and potassium silicate stabilized with sorbitol (Si-alkali) and potassium silicate (Si-K) in five concentrations (0, 0.25, 0.5, 0.75 and 1.0 mmol L−1), and 4 repetitions. The Si syrup pH was adjusted to 5.5 ± 0.2. The foliar spraying of Si on pre-sprouted sugarcane seedlings is feasible since it increased Si accumulation, and benefited seedling production and plant initial growth. Soluble Si sources with stabilizers increased Si accumulation more efficiently compared to potassium silicate (Si-K) and nanosilica (Si-nano). Plants that have been sprayed with the PEG-400-stabilized monosilicic acid (Si-acid) and the sorbitol-stabilized sodium and potassium silicate (Si-alkali) at 0.5 and 0.6 mmol L−1 concentrations, respectively, promote had greater Si accumulation and beneficial effects in the growth of pre-sprouted sugarcane seedlings in production phase. In the initial growth of sugarcane, the sources Si-acid and S-alkali also increase the buildup and beneficial effects, but both sources at 0.6 mmol L−1 concentrations.

Growth of pre-sprouted sugarcane seedlings submitted to supplementary lighting

ABSTRACT Brazil is the largest producer and exporter of sugarcane in the world, and the sugar and ethanol sector has invested in the development of new technologies and methods of planting to meet the market demand. Thus, the aim of this study was to evaluate the performance of sugarcane at the acclimation phase and under field conditions, from pre-sprouted seedlings exposed to supplementary lighting, through light-emitting diode, in the period of acclimation in a greenhouse. The experiment was carried out in Carpina, PE, Brazil, from January to September 2017. The experimental plots were composed of pre-sprouted seedlings acclimated in greenhouse, exposed to the supplementary lighting systems, 90% Red + 10% Blue (R:B 90/10), 80% Red + 20% Blue (R:B 80/20), 70% Red + 30% Blue (R:B 70/30) and a control. The evaluation of seedling growth was performed through the measurement of biometric indicators: plant height (cm); stem length (cm); stem diameter (cm) and number of tillers. The biometric indicators showed no significant differences, but plants under lighting systems with a greater proportion of the red wavelength (R:B 80/20 and R:B 90/10) showed higher percentage of survival in the field.

Pre-sprouted Seedlings of Sugarcane Using Sugarcane Industry By-products as Substrate

The present study aimed to evaluate the chemical and physical/hydraulic properties of sugarcane bagasse and filter cake substrates in different compositions and proportions with sand and subsoil, as well as their use in the development of pre-sprouted seedlings (PSS) of sugarcane. The treatments were set up in a 5 × 5 factorial completely randomized design, with five proportions [(0, 0.25, 0.5, 0.75 and 1.00, on a volumetric basis (v/v)] of bagasse or cake in five compositions with sand or subsoil [Bagasse (Sand), Bagasse (Subsoil), Bagasse (Cake), Cake (Subsoil) and Cake (Sand)], totaling 25 treatments with three replications. As a reference to the formulated substrates, we used the commercial substrate Trimix®. The chemical (pH and electrical conductivity) and physical (density, total porosity, aeration space, water holding capacity and particle size) properties were evaluated for the substrate characterization and the agronomic and productive variables for the characterization of PSS growth. The by-products, namely filter cake and sugarcane bagasse, recommended in the production of substrates can be used in the production of pre-sprouted seedlings of sugarcane from individualized buds. Equivalent volumetric proportions of cake and bagasse at 50% of each promoted growth and biomass production of pre-sprouted seedlings of sugarcane.

Silicon in Pre-sprouted Sugarcane Seedlings Mitigates the Effects of Water Deficit After Transplanting

This study is aimed at assessing whether silicon (Si) can mitigate the effects caused by water stress in pre-sprouted seedlings (PSS) in sugarcane after their transplanting in the soil and what is the best form in the application if via nutrient solution or leaf spraying. The treatments were arranged in a 3 × 3 factorial scheme with silicon supply via nutrient solution (2 mmol L−1), Si via leaf application (3.4 mmol L−1), and without Si (control) and three levels of soil water retention capacity (70%, 50%, and 30%), for 30 days. In the absence of Si, the water deficit was damaging to the physiological, growth, and dry matter production variables of plants, in a 30% level of soil water retention capacity. Silicon supply via nutrient solution was more efficient when compared with Si via leaf spraying in the formation of pre-sprouted sugarcane seedlings in the first 30 days after transplanting, since it increased the quantum efficiency of photosystem II, chlorophyll content, leaf water potential, and water content, decreased cell electrolyte leakage and free proline content, and allowed a higher growth and biomass production. In conclusion, the supply of Si via nutrient solution in pre-sprouted sugarcane seedlings can be considered a feasible alternative to alleviate water deficit damage imposed after transplanting, in a 30% level of soil water retention capacity.

Biological nematicides associated with biofertilizers in the management of Pratylenchus zeae in sugarcane

The aim of the present study was to assess Pratylenchus zeae control in sugarcane by using biological nematicidesin association, or not, with biofertilizers. Sugarcane pre-sprouted seedlings were transplanted to pots and inoculated with 2 mLof a solution containing 1000 P. zeae in the planting furrows, treated with the combinations based on two biological nematicides,three biofertilizers, and their respective controls, and one absolute control (without treatment or nematode). Results evidencedthat biological nematicides based on Trichoderma harzianum and Bacillus spp., when applied alone, promoted reductions in thenematode population of 33.81 and 31.62%, respectively. For nematodes per gram of root, the reductions were 34.67 and 25.38%.On the other hand, biofertilizers efficiency in the nematode reproduction presented variations. However, all treatments reducednematode penetration in the sugarcane root system, with reductions varying from 31.17 to 53.21%. The same was observed inthe mortality test, where nematode mortality ranged from 38.95 to 81.10%.

Quality of multi-row harvesting in sugarcane plantations established from pre-sprouted seedlings and billets

The mechanical planting and harvesting of sugarcane have experienced great technological transformations in Brazil. A pre-sprouted seedling system launched in 2012 is being used widely throughout the country, and new inter-row spacing configurations have been proposed due to the introduction of new multi-row harvesters. The aim of the present study was to evaluate the quality of the mechanical harvesting of sugarcane as performed by a multi-row harvester in three different planting systems, using statistical process control as a tool. The experiment was performed in an agricultural area located in Guariba, in the state of São Paulo, Brazil. The quality of harvesting performed by a multi-row harvester was evaluated in three different planting systems: PSS1, pre-sprouted seedlings with row spacing of 1.25 m; PSS2, pre-sprouted seedlings spaced 1.50 m; and BIL, billets with spaced 1.50 m. The planting material (billet or seedling) and spacing between rows affected the harvesting process. PSS1 presented the lowest process variability for all the evaluated quality indicators except for the damage index. The harvesting process was stable for the cutting height, damage index and soil penetration resistance. BIL presented the highest process variability, and its harvesting process was only stable for the loss index and soil penetration resistance.

Sprouting of pre-sprouted sugarcane seedlings and micrometeorological variables under photo-selective nets

ABSTRACT Sugarcane is a grass species that stands out worldwide in the production of ethanol. Brazil is the world’s largest producer and leader in exports, responsible for more than 50% of the products that are marketed worldwide. The objective of this study was to investigate the effect of photo-selective nets on micrometeorological variables and on sprouting of pre-sprouted sugarcane seedlings. The experiment was carried out in a protected environment at Universidade Federal Rural de Pernambuco - UFRPE, in a completely randomized design. Seedlings of cultivar RB92579 were obtained by the technique of production of pre-sprouted seedlings. The protected environment was divided into four modules corresponding to the treatments: covered with anti-UV low-density polyethylene plastic: + Solpack® red ultranet net, + Solpack® white net, + Solpack® freshnet net and without shade net. Micrometeorological data of air temperature and substrate temperature were recorded in each module. The first count of emergence, sprouting speed index and sprouting percentage were calculated. Principal component analysis was used to verify the association between the cultivation modules and the micrometeorological and sprouting variables of the seedlings. Air temperature in the protected environment was 8.7% higher than that in the external environment. The white net led to sprouting of 78.93%. The substrate temperature above 30.4 °C favored seedling sprouting. The modules with white net and red ultranet net favored seedling sprouting.

Production of sugarcane seedlings pre-sprouted in commercial and alternative substrates with by-products of the sugarcane industry

The sugarcane agro-industry is a major producer of organic waste, which could be used as substrates for production of pre-sprouted sugarcane seedlings aiming at reducing production costs and the sustainability of the sugar and alcohol industry. This study aimed to identify the best position of origin of the bud chip (little portion of stem with one bud) for the production of pre-sprouted seedlings (PSS) of sugarcane and the effects of commercial and alternative substrates containing by-products of the sugarcane industry on the production of sugarcane PSS. For this, a 4x2 factorial experiment was performed with four substrates: two commercial (TRIMIX® and BIOPLANT®) and two substrates formulated from sugarcane bagasse and filter cake (SABAFI and SUSBAFI) combined with bud chip from the basal and apical regions. The chemical and physical-hydric properties of the substrates and the development of PSS were evaluated. The substrates evaluated provided contrasting environments for root growth in relation to the physical-hydric and chemical properties. The use of by-products from the sugarcane industry can be added to the formulation of substrates for the production of pre-sprouted sugarcane seedlings, although the commercial substrate TRIMIX® provides superior performance to the seedlings, regardless of the origin position of the bud chip.

Herbicide selectivity in pre-sprouted seedlings of ‘CTC14’ sugarcane

ABSTRACT: A new sugarcane planting system, using pre-sprouted seedlings (PSS) to replace sugarcane stem fragments, substantiates the hypothesis of this study that there might be seedling toxicity by herbicides that are sprayed at pre-emergence in traditional systems. Therefore, the aim of this paper was to study the selectivity of herbicides applied at pre-planting in PSS. A field experiment was conducted in a randomized block design, using seven treatments and four replications. Herbicides were sprayed and, 24 hours later, the seedlings were planted. At the beggining of seedling development, all herbicide treatments showed phytotoxicity, but the symptoms decreased with the growth and development of seedlings, with no difference in height, stem diameter, number of leaves, quantum efficiency of PSII (Fv/Fm) and dry matter of plants between treatments. There was also no significant difference in the yield and technological characteristics of stems. All herbicides used were selective to sugarcane seedlings when applied at pre-planting in the PSS system.

Weed Interference Periods in Pre-Sprouted Sugarcane Seedlings

ABSTRACT: The aim of this research was to determine weed interference periods in sugarcane cultivated under the system of pre-sprouted seedlings, taking into account the impact on the final plant stand, and bud yield and stalk yield. In the field, this study used a randomized block design with 14 treatments and four replications. The treatments consisted of periods of control and weed coexistence with the sugarcane crop (cultivar IACSP95-5000): 30, 60, 90, 120, 150, 180, 210 and 240 days after planting. A phytosociological survey was carried out in the experimental area, and the species Merremia aegyptia, Urochloa decumbens and Nicandra physaloides were found to be predominant. At the end of 240 days, regression analysis was performed according to Boltzmann’s sigmoidal model and considering loss tolerance of 5% in the evaluated variables. For final plant stand, the period prior to interference was 31 days and the total period of interference prevention was 187 days. For bud yield, the period prior to interference was 23 days and the total period of interference prevention was 178 days. For stalk yield, the period prior to interference was 19 days and the total period of interference prevention was 195 days. Weed interference was detrimental to all evaluated variables, with losses of up to 100% of the sugarcane plants after 120 days of weed coexistence.

Pre-sprouted seedlings production methods through buds or mini-stems: Emergence and initial development of sugarcane cultivars

This study evaluates the emergence and initial development of sugarcane cultivars with different bud sizes, based on the system of pre-sprouted seedlings (PSS). Early sugarcane cultivars (RB966928, RB855156 and IACSP91-1099) were evaluated. These evaluations comprised three positions of the sugarcane stem (tip, middle and base) and four types of sugarcane propagules (mini-stem and 3 bud sizes with different diameters: 22 mm (1), 29 mm (2) and 35 mm (3)). Three trials were performed, each with a different cultivar. The experimental design for each cultivar was a randomized block in a 3x4 factorial scheme (stem position x propagule size (vegetative material)) with 4 replicates. Emergence was evaluated daily, and from these evaluations the emergence speed index (ESI) was calculated. Plant height, shoot dry mass and root dry mass were also assessed. Data were submitted to analysis of variance with interaction, and the Tukey test was applied. When simple variable transformations were not enough to meet the assumptions of normality and homoscedasticity, the non-parametric Friedman test was used. ESI indicated that the best type of propagule was the mini-stem, and for cultivars IACSP91-1099 and RB855156 the best performing position was the tip. The Friedman test indicated significance of the causes of variation related to propagule size and stem position for shoot dry mass in all evaluated cultivars. In addition, the test indicated significant variation of root dry mass for cultivars IAC91-1099 and RB966928 between propagule sizes and the stem positions. The height of cultivar IACSP91-1099 showed interaction between the different propagule sizes and stem positions. The greatest increase of height in sugarcane seedlings occurred for the mini--stem propagule and tip position. Cultivars RB855156 and RB966928 also showed interaction between the different propagule sizes and stem positions. Cultivar RB855156 showed the highest plant height with the mini- -stem propagule at the tip position, however it did not differ statistically from the propagule with size 3 at the tip and middle positions. The mini-stem and the bud with size 3, removed from the tip of the stem, are the best alter­natives for seedling production.

Development of pre-sprouted seedlings (PSS) of sugarcane under different amounts of filter cake and application modes

The sugarcane pre-sprouted seedlings (PSS) system is a new multiplication technology that contributes to the rapid production of seedlings and is associated with a high standard of vegetal health, vigour and uniformity of planting, as well as a drastic reduction in the use of seedlings per area. Due to the high moisture required during the initial period of growth, the filter cake can be an ally in the development of this technology. Thus, this work aimed to evaluate the development of sugarcane PSS, under different amounts of filter cake and application modes. The treatments included five doses of filter cake at 0, 7.5, 15, 30, and 45 t ha-1 and two forms of application: depth (0.30 m) and surface. Once formed, the sugarcane PPS were planted in Eutroferric Red Latosol, with due treatments. For aerial development analyses, leaf area, stem length and diameter and shoot dry mass were evaluated at 15, 30, 45, 60, 75 and 90 days after planting. The filter cake positively influenced the development of pre-sprouted seedlings, promoting greater leaf area and stalk diameter when applied on the surface. The dose of 30 t ha-1 to the surface, provided 54% higher shoot dry weight and 56% more dry weight of roots compared to cultivation without its application, demonstrating its usefulness to improve the development of pre-sprouted seedlings.

Crescimento inicial de mudas pré-brotadas de cana-de-açúcar em duas modalidades de aplicação de herbicidas

A espécie Cyperus rotundus está entre as plantas daninhas mais difíceis de controlar, podendo causar elevados prejuízos na cultura da cana-de-açúcar. As práticas adotadas garantem os valores de produtividade, dentre elas, está o manejo de plantas daninhas. O objetivo deste trabalho foi avaliar o crescimento inicial de mudas pré-brotadas de cana-de-açúcar submetidas à aplicação de herbicidas em pré ou pós-plantio. Foram conduzidos dois experimentos (pré e pós-plantio) em casa-de-vegetação, em delineamento inteiramente casualizado, com quatro repetições. Os tratamentos correspondem aos herbicidas aplicados em três doses em pré-plantio: sulfentrazone (400, 800 e 1.600 g i.a. ha-1), diclosulam (96,6; 193,17 e 386,34 g i.a. ha-1), imazapic (66,5, 133 e 266 g i.a. ha-1) e imazapyr (250, 500 e 1.000 g e.a. ha-1) e pós-plantio: ethoxysulfuron (67,5, 135 e 270 g i.a. ha-1), halosulfuron (56,25, 112,5 e 225 g i.a. ha-1), 2,4-D (670, 1.340 e 2.680 g e.a. ha-1) e MSMA (987,5, 1975 e 3.950 g i.a. ha-1). Além de duas testemunhas sem aplicação de herbicidas. Foram avaliados os sintomas de injúrias, altura, diâmetro, número de folhas, número de perfilhos, teor de clorofila, área foliar, matéria seca da parte aérea e raiz. Os herbicidas em pós-plantio foram considerados seletivos, uma vez que os sintomas de injúrias foram baixos e os outros parâmetros avaliados não foram diferentes da testemunha. Para as aplicações em pré-plantio foram observados sintomas de injúrias até os 60 dias após a aplicação (DAA) para sulfentrazone.

Initial interference of Cyperus rotundus L. in pre-sprouted seedlings of sugarcane cultivars RB985476 and IACSP95-5000

Weeds compete with plants for water, light, nutrients and space. In sugarcane, planting pre-sprouted sugarcane seedlings (PSS) may mean a change in weed interference and management. The aim of this study was to generate information on the interference of Cyperus rotundus L. in PSS. Two experiments were carried out in a completely randomized design, one with cultivar RB985476, with seven densities of C. rotundus (0, 17, 35, 70, 140, 280 and 560 plants m-2), and the second with cultivar IACSP95-5000, with four densities of C. rotundus (0, 70, 140 and 280 plants m-2). For this weed, a 2x6 factorial design was used for the experiment with RB985476 and a 2x3 design was used for IACSP95-5000, the first factor being absence and presence of the crop, and the second factor the densities of the species. Biometric evaluations of height, diameter, number of tillers and leaves, leaf area and dry mass were carried out. The PSS had a reduction in height, number of leaves and leaf area in the main till at 60 d after planting (DAP) in RB985476. For the IACSP95-5000 cultivar, there was no reduction in the analyzed variables. The average dry mass per plant of C. rotundus decreased as the density of the species increased in the absence of PSS.

Productivity and technological quality of sugarcane cultivars fertigated and planted through pre-sprouted seedlings

Productivity and technological quality of sugarcane cultivars fertigated and planted through pre-sprouted seedlings

Performance of pre-sprouted sugarcane seedlings in response to the application of humic acid and plant growth-promoting bacteria

Sugarcane cultivation using pre-sprouted seedlings has decreased the number of stalks used per hectare, increased the multiplication rate, improved seedling health, and increased planting uniformity. However, because this system has been only recently proposed, the number of studies evaluating this new technology is still scarce, particularly those examining the effect of the application of growth-promoting substances on seedling characteristics during the production phase. Here, we hypothesized that it is possible to combine the plant growth-promoting activity of humic acid (HA) with the inoculation of selected strains of plant growth-promoting bacteria (PGPB) to improve the yield of sugarcane seedlings compared with the individual application of these two techniques. The potential of the combined use of HA and PGPB as agricultural inputs was evaluated by conducting an experiment with sugarcane micro cuttings in a greenhouse. Treatments included control, PGPB, HA, and PGPB with HA. At the end of the experiment (60 d after planting), the plants were subjected to biometric evaluation. The results indicated that it was possible to combine HA with selected strains of PGPB (Burkholderia sp.) to improve the yield of seedlings compared with individual HA and PGPB treatments. HA, PGPB, and HA + PGPB increased the total dry matter compared with the control by 23%, 25%, and 36%, respectively. Therefore, the use of HA-based plant regulators in combination with PGPB was more effective than the isolated use of these inputs for the treatment of micro cuttings and improvement of sugarcane seedling yield.