Commercial Sugarcane Fields Research Articles

First Report of Damage by the Sugarcane Root WeevilDiaprepes abbreviatus(Coleoptera: Curculionidae) to Florida Sugarcane

The weevil Diaprepes abbreviatus (L.) occurs naturally in the Lesser and Greater Antilles where it is considered an important pest of sugar cane and citrus, particularly in Barbados and Pu erto Rico (Woodruff 1968). Woodruff (1968) pre sents a review of D. abbreviatus with respect to geographical distribution, biology, damage (em phasizing citrus) and control. The importance of the weevil as a pest of sugarcane is evidenced by common use in early literature of the following name for the weevil: the sugarcane rootstock borer weevil. D. abbreviatus was first reported in Florida during 1964 in citrus near the town of Ap opka (Schroeder & Jones 1983). An eradication ef fort was made, but the weevil was rediscovered in this area during 1968. The weevil has subse quently spread across Florida, although second ary introductions from the Caribbean may have occurred. Regarded to be a poor flier, the spread of the weevil is usually attributed to the movement of infested ornamental plants. Larvae and adults are highly polyphagous (Simpson et al. 1996), al though cane and citrus have been shown to sup port larval development better than any of 71 other plant species (Schroeder et al. 1979). The presence and spread of the weevil in Flor ida during the 1970s and 1980s alarmed the sugar industry. By 1981, 61,700 acres (24,978 ha) had been quarantined for the weevil across a number of counties, yet at that time the weevil had not been found attacking sugarcane in the Everglades Agricultural Area where most sugar cane is grown. D. abbreviatus was found in South Bay during 1992, Moore Haven during 1993, and in Canal Point during 1995 (all in ornamental plant nurseries), placing known infestations within the heart of the sugar production area. United States Sugar Corporation, one company particularly concerned about the weevil, moni tored sugarcane in the vicinity of these three towns for infestations of the weevil during the late 1990s and early 2000s. Adult weevils were sometimes found in the vicinity of commercial sugarcane in association with weeds such as hemp sesbania (Sesbania macrocarpa Muhl.), sickle pod (Cassia obtusifolia L.), pigeon pea (Ca janus cajan (L.) Millsp.), Brazilian peppertree (.Schinus terbinthifolius Radd.), and other plants growing in or near cane fields, but no larval infes tations or signs of damage to cane by the weevil were found (Hall, personal communication). In Feb 2010, Ron Cherry was contacted by ex tension specialist Les Baucum concerning a po tential grub problem in commercial sugarcane fields. These fields were located ca. 5 km south of

Active crop sensor to detect variability of nitrogen supply and biomass on sugarcane fields

Nitrogen management has been intensively studied on several crops and recently associated with variable rate on-the-go application based on crop sensors. Such studies are scarce for sugarcane and as a biofuel crop the energy input matters, seeking high positive energy balance production and low carbon emission on the whole production system. This article presents the procedure and shows the first results obtained using a nitrogen and biomass sensor (N-Sensor™ ALS, Yara International ASA) to indicate the nitrogen application demands of commercial sugarcane fields. Eight commercial fields from one sugar mill in the state of Sao Paulo, Brazil, varying from 15 to 25 ha in size, were monitored. Conditions varied from sandy to heavy soils and the previous harvesting occurred in May and October 2009, including first, second, and third ratoon stages. Each field was scanned with the sensor three times during the season (at 0.2, 0.4, and 0.6 m stem height), followed by tissue sampling for biomass and nitrogen uptake at ten spots inside the area, guided by the different values shown by the sensor. The results showed a high correlation between sensor values and sugarcane biomass and nitrogen uptake, thereby supporting the potential use of this technology to develop algorithms to manage variable rate application of nitrogen for sugarcane.

Mexican Rice Borer (Lepidoptera: Crambidae) Oviposition Site Selection Stimuli on Sugarcane, and Potential Field Applications

The Mexican rice borer, Eoreuma loftini (Dyar) (Lepidoptera: Crambidae), a key pest of sugarcane (Saccharum spp.) and rice, Oryza sativa L., in Texas, has not been controlled with chemical insecticides or biological agents, but some sugarcane varieties have shown degrees of resistance. Assessment of selected sugarcane leaf characteristics indicate that preference for oviposition sites is mostly determined by the presence of a leaf fold and secondarily by the availability of dry leaf tissue, both of which are antixenotic nonchemical stimuli. We suggest that breeding sugarcane lines bearing leaves that do not fold on drying could provide substantial antixenotic resistance against the Mexican rice borer. Previously identified antixenotic chemical stimuli, i.e., low quantities or absence of important nutrients in green leaf tissue, only become apparent when resistant and susceptible sugarcane varieties are compared. Varietal differences in oviposition preference, however, were not observed on excised dry leaf tissue, indicating that expression of resistance in terms of chemical stimuli requires detection of biochemicals in nearby living leaf tissue. Excised dry sugarcane leaves retain the two dominant nonchemical oviposition preference stimuli for Mexican rice borers, and the leaves effectively trapped eggs away from intact plants when dry leaves were used as "mulch" at the bottom of greenhouse cages. Under commercial sugarcane field conditions, bundled dry leaves also collected Mexican rice borer eggs. Possible applications of dry sugarcane leaf substrate for egg scouting and for trapping eggs are discussed.

Boundary Lines Used to Determine Sugarcane Production Limits at Leaf Nutrient Concentrations Less than Optimum

Foliar nutrient analysis is a useful diagnostic tool to complement soil testing as a best‐management practice with sugarcane (Saccharum spp.). This study was conducted to determine sugarcane production limits at leaf nutrient concentrations less than optimum. Eight Florida sugarcane growers participated in a survey of leaf nutrient values in 2004, 2005, and 2006. A total of 412 leaf samples were collected from individual commercial sugarcane fields, from which there were 389 harvest data/leaf data combinations. Fields were selected to be representative of plant cane, first ratoon, and second ratoon crops; mineral and organic soils of the area; and major commercial sugarcane cultivars. Leaf silicon (Si), magnesium (Mg), and manganese (Mn) concentrations had the strongest correlations with tons sugarcane ha−1 on organic soils, and leaf nitrogen (N), Mg, and Si concentrations had the strongest correlations with tons sugarcane ha−1 on mineral soils. Boundary lines were used to define practical limits of tons sugarcane ha−1 for leaf nutrient concentrations less than optimum. A table was developed that provides approximate leaf concentrations of nine nutrients at which 10 and 25% losses in relative tons sugarcane ha−1 were estimated. Boundary‐line analysis indicated that sugarcane production was most limited nutritionally in survey fields by insufficient Mg, iron, N, and Si on mineral soils and by insufficient Si and Mn on organic soils.

Orbital spectral variables, growth analysis and sugarcane yield

Temporal analysis of crop development in commercial fields requires tools for large area monitoring, such as remote sensing. This paper describes the temporal evolution of sugar cane biophysical parameters such as total biomass (BMT), yield (TSS), leaf area index (LAI), and number of plants per linear meter (NPM) correlated to Landsat data. During the 2000 and 2001 cropping seasons, a commercial sugarcane field in Araras, São Paulo state, Brazil, planted with the SP80-1842 sugarcane variety in the 4th and 5th cuts, was monitored using nine Landsat images. Spectral data were correlated with agronomic data, obtained simultaneously to the imagery acquisition. Two methodologies were used to collect spectral data from the images: four pixels (2 × 2) window and average of total pixels in the field. Linear and multiple regression analysis was used to study the spectral behavior of the plants and to correlate with agronomic variables (days after harvest-DAC, LAI, NPM, BMT and TSS). No difference was observed between the methodologies to collect spectral data. The best models to describe the spectral crop development in relation to DAC were the quadratic and cubic models. Ratio vegetation index and normalized difference vegetation index demonstrated correlation with DAC, band 3 (B3) was correlated with LAI, and NDVI was well correlated with TSS and BMT. The best fit curves to estimate TSS and BMT presented r² between 0.68 and 0.97, suggesting good potential in using orbital spectral data to monitor sugarcane fields.

Aproveitamento pela cana-de-açúcar da adubação nitrogenada de plantio

O balanço de 15N de fontes nitrogenadas no sistema solo-planta tem sido de muita valia em estudos das transformações do N em diferentes agroecossistemas. No agrossistema da cana-de-açúcar, nas condições brasileiras, a resposta à adubação nitrogenada de cana-planta ainda é questão não totalmente esclarecida e a utilização de fertilizantes nitrogenados marcados com 15N pode auxiliar no entendimento dessa lacuna. Com o objetivo de avaliar o aproveitamento do N da uréia pela cana-de-açúcar no ciclo agrícola de cana-planta, realizaram-se dois experimentos em área comercial de cana-de-açúcar, com o cultivar SP81-3250. Esses experimentos foram feitos de fevereiro de 2005 a julho de 2006. O delineamento experimental foi o de blocos ao acaso, sendo os tratamentos constituídos de três doses de N: 40, 80 e 120 kg ha-1, na forma de uréia, e uma testemunha sem fertilização nitrogenada. No centro das parcelas com doses de N-uréia, foram instaladas microparcelas que receberam o fertilizante marcado com 15N. A recuperação de 15N-uréia pela cana-planta (planta toda) foi na média dos experimentos de 30, 30 e 21 %, respectivamente, para as doses de 40, 80 e 120 kg ha-1 de N. A menor recuperação do N-uréia nas maiores doses, especialmente na de 120 kg ha-1, deveu-se às perdas de N do sistema solo-planta. O aproveitamento do N da uréia (15N) representou em média 11,7 % do N total acumulado na planta toda. A distribuição do N proveniente do fertilizante nas diversas partes da planta não variou com a dose de N, sendo em média de 50 % nos colmos, 22 % nas folhas secas, 20 % nos ponteiros e 8 % nas raízes.

Abundance and Spatial Distribution of Wireworms (Coleoptera: Elateridae) in Florida Sugarcane Fields on Muck versus Sandy Soils

Wireworms are important insect pests of Florida sugarcane. Our objective was to determine the abundance and spatial distribution of wireworms in Florida sugarcane on muck versus sandy soils. Fourteen commercial sugarcane fields were sampled for wireworms on farms in southern Florida. Melanotus communis (Gyllenhal) was the most abundant wireworm found in both soil types. Other less abundant wireworms found and discussed are Conoderus spp., Ischiodontus sp., and Glyphonyx bimarginatus Schaeffer. There were no significant differences in densities of G. bimarginatus, M. communis, or total wireworms of all species in muck versus sand fields. Significantly more Conoderus spp. were found in sandy fields and significantly more Ischiodontus sp. were found in muck fields. The spatial distribution of the wireworms within fields was similar in both soil types. In muck, wireworms in 4 fields were randomly distributed, aggregated in 3 fields, and uniformly distributed in no fields. In sand, wireworms in 3 fields were randomly distributed, aggregated in 4 fields and uniformly distributed in no fields.

Spectral variables, growth analysis and yield of sugarcane

Spectral information is well related with agronomic variables and can be used in crop monitoring and yield forecasting. This paper describes a multitemporal research with the sugarcane variety SP80-1842, studying its spectral behavior using field spectroscopy and its relationship with agronomic parameters such as leaf area index (LAI), number of stalks per meter (NPM), yield (TSS) and total biomass (BMT). A commercial sugarcane field in Araras/SP/Brazil was monitored for two seasons. Radiometric data and agronomic characterization were gathered in 9 field campaigns. Spectral vegetation indices had similar patterns in both seasons and adjusted to agronomic parameters. Band 4 (B4), Simple Ratio (SR), Normalized Difference Vegetation Index (NDVI), and Soil Adjusted Vegetation Index (SAVI) increased their values until the end of the vegetative stage, around 240 days after harvest (DAC). After that stage, B4 reflectance and NDVI values began to stabilize and decrease because the crop reached ripening and senescence stages. Band 3 (B3) and RVI presented decreased values since the beginning of the cycle, followed by a stabilization stage. Later these values had a slight increase caused by the lower amount of green vegetation. Spectral variables B3, RVI, NDVI, and SAVI were highly correlated (above 0.79) with LAI, TSS, and BMT, and about 0.50 with NPM. The best regression models were verified for RVI, LAI, and NPM, which explained 0.97 of TSS variation and 0.99 of BMT variation.

Can economic injury levels be derived for sugarcane weevil borer, Rhabdoscelus obscurus (Boisduval) (Coleoptera: Curculionidae), in far‐northern Queensland?

Abstract Split‐cane traps were used to monitor trends in sugarcane weevil borer populations in eight commercial sugarcane fields of far‐northern Queensland during the 2000–02 cane‐growing seasons. Adult borers first appeared in all fields in December–January and numbers increased gradually. Populations declined in most fields in February, followed by another increase during March–April. Trap catches started to decline steadily in early June and were the lowest by harvest time (August–October). Similar population trends were seen in the 2 years. Multiple‐regression analysis showed that borer activity is highly dependent on minimum temperature, with rainfall having no clear impact on borer dynamics. Damaged stalks per hectare and damaged internodes per stalk ranged between 6.3 and 28.6% and 0.15–0.83, respectively, and infestations were associated with losses of commercial cane sugar (CCS) of up to 1.96 units. Numbers of adult borers caught in split‐cane traps during the season were not correlated with the number of damaged stalks or internodes at the end of the season in all cases, and similar borer densities resulted in different damage rates. Hence, calculation of a precise economic injury level is not feasible. Treatment with Regent® (Rhône‐Poulenc Rural, NSW, Australia) (200 g L−1 fipronil at 75 g active ingredient per hectare) would be economical when borer damage exceeded 0.3–0.4 internodes per stalk. This level of damage is not uncommon in many areas of far‐northern Queensland, so insecticidal treatment may be cost effective in areas of high weevil borer infestation.

A process-based model to simulate changes in tiller density and light interception of sugarcane crops

Tiller density on commercial sugarcane fields is a dynamic variable and part of the canopy that interacts with the environment. Three internal processes influence tiller density in well-watered crops. Those are (1) primary tiller germination, (2) underground branching (tillering) and (3) tiller senescence. Current sugarcane models depend on light interception, partly determined by tiller density, to simulate photosynthesis and evapotranspiration. In this paper a model is described that takes mechanistic canopy processes, like tillering and light competition into consideration. Five phases of canopy development are described. The model was calibrated on one cultivar and has mean errors close to half those of the CANEGRO model in tiller numbers per ha (RMSE=78,577 cf. RMSE=149,084) and%PAR light interception (RMSE=8.5 cf. RMSE=13.8), respectively. The model's mechanistic nature enables its application in more sensitive tiller and canopy dependent processes, such as high tiller densities, extensive ratooning and stool damage.

Norms establishment of the Diagnosis and Recommendation Integrated System (DRIS) for nutritional diagnosis of sugarcane

The objectives of this study were to establish DRIS norms for sugarcane crop, to compare mean yield, foliar nutrient contents and variance of nutrient ratios of low- and high-yielding groups and to compare mean values of nutrient ratios selected as the DRIS norms of low- and high-yielding groups. Leaf samples (analyzed for N, P, K, Ca, Mg, S, Cu, Mn and Zn contents) and respective yields were collected in 126 commercial sugarcane fields in Rio de Janeiro State, Brazil and used to establish DRIS norms for sugarcane. Nearly all nutrient ratios selected as DRIS norms (77.8%) showed statistical differences between mean values of the low- and high-yielding groups. These different nutritional balances between the low- and high-yielding groups indicate that the DRIS norms developed in this paper are reliable. The DRIS norms for micronutrients with high S²l /S²h ratio and low coefficient of variation found can provide more security to evaluate the micronutrient status of sugarcane.

N-15 natural abundance studies in Australian commercial sugarcane

The measurement of natural N-15 abundance is a well-established technique for the identification and quantification of biological N-2 fixation in plants. Associative N-2 fixing bacteria have been isolated from sugarcane and reported to contribute potentially significant amounts of N to plant growth and development. It has not been established whether Australian commercial sugarcane receives significant input from biological N-2 fixation, even though high populations of N-2 fixing bacteria have been isolated from Australian commercial sugarcane fields and plants. In this study, delta(15)N measurements were used as a primary measure to identify whether Australian commercial sugarcane was obtaining significant inputs of N via biological N-2 fixation. Quantification of N input, via biological N-2 fixation, was not possible since suitable non-N-2 fixing reference plants were not present in commercial cane fields. The survey of Australian commercially grown sugarcane crops showed the majority had positive leaf delta(15)N values (73% >3.00parts per thousand, 63% of which were <5.00parts per thousand), which was not indicative of biological N-2 fixation being the major source of N for these crops. However, a small number of sites had low or negative leaf delta(15)N values. These crops had received high N fertiliser applications in the weeks prior to sampling. Two possible pathways that could result in low delta(15)N values for sugarcane leaves (other than N-2 fixation) are proposed; high external N concentrations and foliar uptake of volatilised NH3. The leaf delta(15)N value of sugarcane grown in aerated solution culture was shown to decrease by approximately 5parts per thousand with increasing external N concentration (0.5-8.0 mM), with both NO3- and NH4+ nitrogen forms. Foliar uptake of atmospheric NH3 has been shown to result in depleted leaf delta(15)N values in many plant species. Acid traps collected atmospheric N with negative delta(15)N value (-24.45+/-0.90parts per thousand) from above a field recently surface fertilised with urea. The delta(15)N of leaves of sugarcane plants either growing directly in the soil or isolated from soil in pots dropped by 3.00parts per thousand in the same field after the fertiliser application. Both the high concentration of external N in the root zone (following the application of N-fertilisers) and/or subsequent foliar uptake of volatilised NH3 could have caused the depleted leaf delta(15)N values measured in the sugarcane crops at these sites.

Sugarcane Stemborers and Their Parasites in Southern Texas

Approximately 40,000 stemborer larvae, pupae, and parasite cocoons were collected during 1982–1995 from commercial sugarcane fields and allowed to complete development under laboratory conditions. Eoreuma loftini (Dyar) and Diatraea saccharalis (F.) comprised 92.4% (36,897/39,945) and 5.2% (2,057/39,945) of the stemborers collected. More than 65% of field-collected stem borer larvae completed development and emerged as adults after being transferred to artificial diet; however, 27.5% died during development. Average seasonal parasitization of E. loftini larvae and pupae (including parasites collected during sampling and those that completed development) was 6.2 ± 1.0%. The most numerous parasites collected from E. loftini included 2 indigenous braconids, Chelonus sonorensis Cameron and Digonogastra solitaria Wharton & Quicke, and 2 exotic braconids, Alabagrus stigma (Brulle) [ =Agathis stigmatera (Cresson)] and Allorhogas pyralophagus Marsh. Average seasonal parasitization of D. saccharalis was 8.9 ± 1.6%, caused mostly by Cotesia flavipes (Cameron).

Soil salinity and sugarcane juice quality

Sugarcane ( Saccharum spp. hybrids) juice quality is reduced by soil salinity. If the effect of salinity in commercial production is predictable, it will be possible to estimate juice quality in salt-affected fields prior to harvest. Variation in the effects of soil salinity on sugarcane juice quality in commercial production was assessed using 15-stalk samples harvested in 1992 and 1993 from a salt-affected commercial field of CP 70-321 sugarcane. Mean electrical conductivity (EC e) of saturated water extracts of 54 (1992) or 74 (1993) soil cores from 0–30, 30–60, and 60–90 cm depths were used to calculate mean EC e at each site, which ranged from 0.5–17.0 dS m −1. Most of the increase in EC e was due to increases in Na + and Cl −. Magnesium, Ca 2+ and K + were also present. Stalk samples were harvested from 29 (1992) or 30 (1993) sites, with EC e ranging from 0.5 to 9.5 dS m −1. Each dS m −1 increase in EC e decreased Brix (% soluble solids in juice) and Pol (% sucrose in juice) by about 0.6%, decreased apparent purity (Pol as % of Brix) by 1.3% in 1993, increased juice conductivity 0.8 dS m −1, and increased cane residue (fiber) 0.5%. Effects of EC e on Brix, Pol and conductivity were very similar between years, indicating that the response of juice quality to salinity is predictable. This should allow development of sugar quality maps of commercial sugarcane fields for site-specific management decisions. Recoverable sugar yield per ton cane and per hectare were reduced by EC e in both years. In 1992, juice osmolality was less at the higher EC e sites, but in 1993 it was unaffected by EC e. About 90% of the osmolality of the juice was accounted for by the solutes analyzed (total sugar, Na +, K +, Ca 2+, Mg 2+, and Cl −). Potassium was the most abundant cation in the sugarcane juice (52.5 to 107 mmol c l −1). In 1992 there was a weak curvilinear ( R 2 = 0.35) increase in juice K + as EC e increased, while in 1993 K + tended to increase linearly with EC e ( r 2 = 0.20). Juice Na + increased with EC e from 4.9 to 37.4 mmol c l −1. There were also increases in juice Mg + (11.3 to 42.0 mmol c l −1) and Ca 2+ (2.2 to 22.4 mmol c l −1), with increased EC e. Most of the increase in juice conductivity was due to increases in Cl − (30.8 to 106 mmol c l −1). For most attributes there were no significant differences between years. This study shows in greater detail than most previous studies how soil salinity affects juice ionic composition, osmolality, and the accepted industry measurements of juice quality, Brix, Pol, apparent purity, and conductivity.

Effect of Antitrogus consanguineus (Blackburn) (Coleoptera: Scarabaeidae) infestations on sugarcane yield in Australia

Yield losses caused by the sugar-cane whitegrub Antitrogus consanguineus to the plant crop, first ratoon crop and second ratoon crop of a commercial sugar-cane field planted with cultivar Q 110 and the first and second ratoon crops of a field of cultivar Q 111 were quantified. There were no significant correlations between larval numbers and yield components in the plant crop of Q110. There were significant negative correlations between larval numbers and the weight of millable stalks and the yield of cane and sugar in the first and second ratoon crops of both cultivars. The lowest plot yields of sugar per hectare were 35.0% and 17.1 % of the highest in the first and second ratoon crops of Q110 and 13.9% and 8.5% in the first and second ratoon crops of Q111, respectively. There were significant partial correlations between the number of larvae in both the first and second ratoons and yield components in the second ratoon crop of Q110.

INCIDENCE OF BACILLUS POPILLIAE IN DIFFERENT LIFE STAGES OF FLORIDA SUGARCANE GRUBS (COLEOPTERA: SCARABAEIDAE)

All life stages of Cyclocephala parallela Casey and Ligyrus subtropicus Blatchley were collected from commercial sugarcane fields in southern Florida from May, 1985 to May, 1988. These specimens were examined using phase contrast microscopy for the presence of the milky disease bacteria, Bacillus popilliae Dutky. In addition, field soil temperatures were measured, and the survival of milky grubs under simulated field temperatures was determined in a laboratoiy. Bacillus popilliae was not detected in the eggs or pupae of either grub species. The bacterium was found in 0.2% and 0.3% of adults in C. parallela and L. subtropicus respectively. The highest incidence of B. popilliae in both species was observed in the larval stage being 6.1% and 1.9% in C. parallela and L. subtropicus respectively. Survival data showed that B. popilliae was not limited in its development in infected third instar grubs by soil temperatures at any time during the year in Florida sugarcane fields.

Effect of White Grub (Coleoptera: Scarabaeidae) Infestation on Sugarcane Yields

Yield losses caused by the white grub Ligyrus subtropicus Blatchley to a commercial sugarcane field planted with cultivar CP 65-357 were quantified. Mean numbers of grubs in areas of high and low infestations were 12.14 and 0.88/m of row, respectively. These population levels affected yields significantly, reducing tons of cane per ha and tons of sugar per ha by 28 and 39%, respectively. Surveys conducted with blacklight traps indicated that peak flight activity occurred in June, when 84.3% of the adults were caught.

Vertical Flight Distribution of AdultInopus rubriceps, a Pest of Sugarcane in Australia

Male soldier flies, Inopus rubriceps (Macquart), were not trapped above 2.5 m, the height of an adjacent crop of sugarcane. However, female soldier flies gained considerable altitude on flights during dispersion. The maximum height recorded for a female was 8.6 m. The Welcome swallow, Hirundo neoxena Gould, was observed preying upon dispersing soldier flies above commercial sugarcane fields.

Distribuição do sistema radicular da cana de açúcar var. co. 290, em solo tipo terra-roxa-legítima

No presente trabalho são apresentados os resultados obtidos no estudo do sistema radicular da cana de açúcar var. Co. 290, sob condições normais de cultivo em terra-roxa-legítima, na Usina Tamôio, município de Araraquara e em três idades: seis, doze e dezoito meses. Empregou-se o mesmo método já utilizado para o cafeeiro, com as alterações convenientes à cana de açúcar. Os resultados mostraram que a distribuição do sistema radicular da variedade estudada se apresentou bem homogênea nas diferentes camadas de solo, sendo que o maior adensamento se deu nos primeiros 30 cm com uma média, nas três idades, de 59,3%. Observou-se que aos seis meses as raízes iam além de 2,10m de profundidade, para atingir 3,30 m na planta adulta. O máximo de raízes vivas foi encontrado aos 12 meses, período de intenso crescimento da planta. Calculou-se a quantidade de raízes que essa cultura deixa incorporada ao solo, após o corte. Para uma produção de 100 toneladas de cana por hectare a planta, aos seis meses, já fornece 1,8 toneladas de raízes nessa mesma área, atingindo a 8 toneladas na planta adulta.