Sugarcane Ratoon Research Articles

Impact of habitat manipulation on the diversity and abundance of beneficial and pest arthropods in sugarcane ratoon

Abstract. Prabowo H, Rahardjo BT, Mudjiono G, Rizali A. 2021. Impact of habitat manipulation on the diversity and abundance of beneficial and pest arthropods in sugarcane ratoon. Biodiversitas 22: 4002-4010. Sugar production in Indonesia faces several challenges such as infestation of pests and diseases that lead to decline in sugarcane production and productivity. In order to overcome the loss of yields from the presence of pests, alternative new approaches are sought by solving of the problem that can have a sustainable impact by applying habitat manipulation. Habitat manipulation changes the diversity and density of arthropods populations in agro-ecosystem. In the concept of managing agroecosystems with habitat manipulation, it is hoped that the development of agro-ecosystem resilience against pest management will be expected to be suistainable. The results showed that there was an increase in the number of arthropods in the research area for 20 weeks after the management of agro-ecosystems through habitat manipulation. The arthropods in all the traps were dominated by Collembola, Diptera, Coleoptera, Aranea, and Hymenoptera. There were 44 genera that belong to predators and 8 species are belonging to parasitoids. The diversity index of Shannon-Wiener (H '), Simpson Dominance (C) and Species Evenness (E) was not significantly different between treatment and control, but habitat manipulation treatment was able to increase the number of detritivores, predators, parasitoids, and pollinators by 38.81; 43.88; 58.4; and 75.35%. The full role of arthropods in the food chain of the sugarcane ecosystem has been identified and efforts are needed to optimize the role of natural enemies in the agroecosystem to maintain ecosystem stability. Habitat manipulation can increase the number of beneficial insect populations in short run, but it might take time to increase their diversity in agroecosystem.

Influence of Cultivars and Nitrogen Fertilizer Rates and Application Mode on Yields and Quality Parameters of Ratoon Sugarcane in Western Kenya

Productivity of sugarcane in Kenya has declined despite use of recommended production practices including introduction of elite high yielding and early maturing sugarcane varieties. Farmers continue to use recommended agronomic inputs for the old low yielding and late maturing varieties on these elite varieties. Nitrogen fertilizer rates in single or split doses for old varieties are still in use yet their appropriateness on new varieties remains untested culminating to decline in sugarcane productivity in Kenya. Currently, cane payment is based on delivered milling cane weight. The industry plans to change payment to a combination of quality and yields. Influence of agronomic inputs and timing of harvesting period on proposed mode of payment is unknown. Harvesting age in western Kenya remains 18-20 months after ratooning (MAR). However, optimal age that combines quality and yields is not documented. Influence of these agronomic practices on quality, yields and optimal harvesting age of ratoon crop of new (D8484) and old (CO421) varieties were evaluated in a 2x4x3 split-split-plot design replicated three times. Four rates of nitrogen as urea, all applied at 3 MAR, split once (50-50%) and applied at 3 and 6 MAR or split three times (40-30-30%) and applied at 3, 6 and 9 MAR were evaluated. Yields and quality parameters were monitored from 10th-24th MAR. Variety D8484 out-yielded (p≤0.05) CO421 throughout demonstrating its superiority. Yields reached maximum at 20 and 19 MAR for CO421 and D8484, respectively. Maximum pol and brix were attained at 18 and 15 MAR for CO421 and D8484, respectively, while commercial cane sugar (CCS) was maximum at 18 and 17 MAR for CO421 and D8484, respectively. Results demonstrated that for high returns, D8484 should be harvested between 15-18 MAR while CO421 between 17-19 MAR. The 60 kg N/ha, that produced higher (p≤0.05) output in both varieties, from 16th MAR is recommended for both varieties. Split fertilizer application did not affect productivity.

Yield and Quality of Ratoon Sugarcane Are Improved by Applying Potassium under Irrigation to Potassium Deficient Soils

The current study was carried out at the experimental farm of Rana Sugars Ltd., Buttar Seviyan, Amritsar, Punjab, India, to identify methods to improve the yield and quality of ratoon sugarcane in potassium-deficient soils. The treatments comprised two levels of irrigation, resulting in plants which either received sufficient water (I1) or were water-stressed (I2), and four rates of potassium (K) application: 0 (K1), 40 (K2), 80 (K3) and 120 (K4) kg K2O ha−1. The results showed that the irrigation levels did not influence crop parameters significantly, although all parameters presented higher values for I1-treated plots. Compared to the K1 (i.e., 0 kg ha−1 K fertiliser applied) treatment, the K2, K3 and K4 treatments yielded 11.16, 37.9 and 40.7%, respectively, higher millable canes and 1.25, 5.62 and 13.13% more nodes per plant, respectively. At 280 days after harvest of the first (plant) crop, the I1 treatment provided ratoons which were up to 15.58% higher than those obtained with the I2 treatment, with cane girths up to 7.69% wider and yields up to 7.29% higher than those observed with the I2 treatment. While the number of nodes per plant did not differ significantly between treatments, there were significant differences in other parameters. Quality parameters (with the exception of extraction percentage) were significantly enhanced by the K3 treatment. The benefit-to-cost ratio (B/C) was higher for the I1 treatment than for the I2, due to a reduced productivity associated with the I2 treatment. At both irrigation levels, the K3 treatment resulted in the highest quality parameters. K1-, K2- and K4-treated plots presented more instances of insect infestations than plots receiving the K3 treatment. Relative to the K3 plots, infestation by the early shoot borer (Chilo infuscatellus) was 18.2, 6.0 and 12.2% higher, respectively, in plots that underwent the K1, K2 and K4 treatments, while infestation by the top borer (Scirpophaga excerptalis) was 21.2, 9.21 and 14.0% higher, and that by the stalk borer (Chilo auricilius) was 10.7, 0 and 8.10% higher. Not all infestation differences between treatments were significant. Our research demonstrates that growing sugarcane in potassium-deficient soils with applications of 80 kg K2O ha−1 under irrigation should be recommended to increase yield and quality while minimising insect infestation and to implement sustainable ratoon sugarcane production.

Relationships between Water Balance and the Growth and Yield of Ratoon Sugarcane on Minamidaito Island

Relationships between Water Balance and the Growth and Yield of Ratoon Sugarcane on Minamidaito Island

Prediction of Ratoon Sugarcane Family Yield and Selection Using Remote Imagery

Remote sensing techniques and the use of Unmanned Aerial Systems (UAS) have simplified the estimation of yield and plant health in many crops. Family selection in sugarcane breeding programs relies on weighed plots at harvest, which is a labor-intensive process. In this study, we utilized UAS-based remote sensing imagery of plant-cane and first ratoon crops to estimate family yields for a second ratoon crop. Multiple families from the commercial breeding program were planted in a randomized complete block design by family. Standard red, green, and blue imagery was acquired with a commercially available UAS equipped with a Red–Green–Blue (RGB) camera. Color indices using the CIELab color space model were estimated from the imagery for each plot. The cane was mechanically harvested with a sugarcane combine harvester and plot weights were obtained (kg) with a field wagon equipped with load cells. Stepwise regression, correlations, and variance inflation factors were used to identify the best multiple linear regression model to estimate the second ratoon cane yield (kg). A multiple regression model, which included family, and five different color indices produced a significant R2 of 0.88. This indicates that it is possible to make family selection predictions of cane weight without collecting plot weights. The adoption of this technology has the potential to decrease labor requirements and increase breeding efficiency.

Response of Stubble Shaving Times on Ratoon Yield of Different Sugarcane Genotypes

Ratooning is common practice done in sugarcane with purpose of reducing the total cost of cultivation and early cane maturity. More than 35% of sugarcane productivity is lost due to improper attention of the farmers towards ratoons. Majority of farmers reported that the ratoonability wasn’t good when harvested in December-January. This experiment was carried out to find the appropriate ratoon shaving time with response to different varieties in sugarcane ratoon crop in the year 2018/19 at national sugarcane research project, Jitpur, Bara. The experiment was conducted in split plot design with four levels of cane genotypes as Co – 0238, CoLk – 94184, Co – 0233 and CoS – 07250 as the main plot factor while four harvesting dates as sub plot factor with three replications. Observations of a number of millable canes, single cane weight, plant height and single cane diameter were recorded, tabulated and analyzed in R-studio. Ratoon stubble shaving in the month of November had the highest number of millable canes (88079/ha) which wasn’t significantly different from the stubble shaving in the month of December, January. Likewise, highest cane yield (60.04 mt/ha), single cane weight (0.757 kg), cane diameter (2.11 cm), plant height (1.82 m) were found in early stubble shaving dates. Cane Yield and various yield parameter shows better performance in early ratoon shaving periods i.e. from November to January than late ratoon shaving dates.

How do nitrogen fertilization and cover crop influence soil C-N stocks and subsequent yields of sugarcane?

Sugarcane production for biorenewables demands substantial inputs of nitrogen (N) fertilizer that can lead to environmental consequences, and no clear effect has been reported on soil organic carbon (SOC) and N stocks. The use of a previous legume crops cultivation to add N to soil is a promising strategy to reduce the dependence in synthetic N fertilizer, having an international appeal for sustainable production of bioenergy crops. This study investigates a four-year impact of N fertilization on SOC and N stocks and sugarcane ratoon yields in a sandy and clayey soils, while considering the effects of a legume cover crop cultivated during the renovation period on decreasing N fertilizer requirements. Treatments with N fertilizer rates were arranged in a randomized block design after plant-cane harvest: 60, 120, 180 kg N ha−1 and control (without N) in two paired areas previously managed with Crotalaria spectabilis and bare fallow. Soil samples for SOC and N stocks were quantified at the beginning of the trial, and measured again along with microbiological attributes after four consecutive years, while sugarcane yield was assessed annually. SOC and N stocks were unaffected by N fertilizer rates, whereas the cultivation of cover crop increased soil N storage and microbial biomass carbon. There was limited responsiveness of sugarcane ratoons to additional N supplied by inorganic fertilizer under cover crop, whereas positive responses occurred under bare fallow. Considering the average of four-harvest yields, cover crop increased sugarcane yield by 9 % (5 Mg ha−1) at sandy soil and 15 % (16 Mg ha−1) at clayey soil relative to bare fallow. Cover crop provided an annual N fertilizer replacement of 9 and 15 kg ha−1 in the sandy and clayey soils. The long-lasting historical effect of cover crop in increasing sugarcane yield per area without the need for extra N from fertilizer opens a new possibility to increase the sustainability and alleviate associated greenhouse gas emissions of sugarcane fields by allowing savings in synthetic N fertilizer.

Impacto das Emendas às IAS 16 e IAS 41 na Posição Econômico-financeira das Empresas Sucroenergéticas Brasileiras

Objetivo: Identificar o impacto das emendas às IAS 16 e IAS 41 na posição econômico-financeira das empresas sucroenergéticas brasileiras, no período de transição de 2015 a 2017.Método: Em uma amostra de 64 companhias, utilizou-se o inverso do índice de Comparabilidade de Gray para mensurar o impacto e o teste Wilcoxon pareado para identificar a significância.Originalidade/Relevância: Essa nova política contábil dividiu a planta e a produção em dois ativos, com diferentes modelos de mensuração. No processo de contabilização das lavouras de cana-de-açúcar, a soqueira da cana-de-açúcar, considerada uma planta portadora, passa a ser mensurada pelo custo histórico e classificada como imobilizado, enquanto que a cana em pé continua a ser mensurada pelo valor justo, mas reportada no ativo circulante.Resultados: Os ajustes contábeis retrospectivos impactaram significativamente a maioria das variáveis analisadas. Melhoraram a liquidez corrente e o giro do ativo, bem como impactaram negativamente a participação de capitais de terceiros, a imobilização do patrimônio líquido, a liquidez geral e o retorno sobre o patrimônio líquido. A composição do endividamento, a liquidez seca, a margem líquida, o retorno sobre investimentos e o ciclo operacional se mantiveram relativamente estáveis.Contribuições teóricas/metodológicas: O estudo demonstra que as emendas às IAS 16 e IAS 41 implicam a perda de comparabilidade dos números contábeis e dos indicadores econômico-financeiros em relação a períodos anteriores. Além disso, considerando as peculiaridades das lavouras de cana-de-açúcar, o estudo fornece evidências que contribuem com as discussões sobre a mensuração do valor justo da cana em pé.

Trichoderma asperellum Inoculation as a Tool for Attenuating Drought Stress in Sugarcane.

Drought stress is an important concern worldwide which reduces crop yield and quality. To alleviate this problem, Trichoderma asperellum has been used as a plant growth-promoting fungus capable of inducing plant tolerance to biotic and abiotic stresses. Here, we examined the effect of T. asperellum inoculation on sugarcane plant above and belowground development under drought stress and investigated the role of this fungus on inducing tolerance to drought at physiological and biochemical levels. The experiment was performed in pots under greenhouse conditions, with four treatments and four replicates. The treatments consisted of sugarcane plants inoculated or not with T. asperellum and grown under drought stress and adequate water availability. Drought-stressed sugarcane plants inoculated with T. asperellum changed the crop nutrition and chlorophyll and carotenoid concentrations, resulting in increased photosynthesis rate, stomatal conductance, and water use efficiency compared to the non-inoculated plants. In addition, the antioxidant metabolism also changed, increasing the superoxide dismutase and peroxidase enzyme activities, as well as the proline concentration and sugar portioning. These cascade effects enhanced the root and stalk development, demonstrating that T. asperellum inoculation is an important tool in alleviating the negative effects of drought stress in sugarcane. Future studies should be performed to elucidate if T. asperellum should be reapplied to the sugarcane ratoons.

Effect of Organic Amendments on Soil Carbon Stock, Yield and Quality of Sugarcane Ratoon

A field experiment was conducted during 2018-20 to evaluate the effect of different organic amendments on yield and quality of sugarcane ratoon in calcareous soil at Crop Research Centre, farm at Dr. Rajendra Prasad Central Agricultural University, Pusa, Bihar. The experiment was conducted in randomized block design with 8 treatments viz. control, FYM (farmyard manure) @ 20 t ha-1, biocompost (BC) @ 20 t ha-1, vermicompost (VC) @ 5.0 t ha-1, green manure with moong, sugarcane trash @ 10 t ha-1, FYM + BC+ VC (1: 1: 0.5) @ 20 t ha-1 and recommended dose of fertilizer (RDF) as NPK (170: 50: 60 kg ha-1) and replicated thrice in sugarcane plant-ratoon system. The sugarcane plant crop was taken and after harvest of plant, the ratoon crop was initiated. Addition of organic amendments significantly increased the number of tillers, millable cane and ratoon cane yield which was at par with recommended dose of fertilizer. The cane juice quality was not affected due to different treatments. The mean cane yield (61.7 - 77.1 t ha-1) and sugar yield (4.06-10.56 t ha-1) varied significantly in organic added plots t ha-1 which was found at par with RDF. The sugar yield followed the similar trends of cane yield. The SMBC (soil microbial biomass carbon), CO2 evolution and carbon stocks were significantly higher in organic amendment added plots indicating improvement in soil carbon status. The highest value of CO2 evolution, SMBC and carbon stocks were observed in the treatment receiving FYM+BC+VC in combination (1: 1: 0.5). Organic amendments had beneficial impact on restoration of soil carbon status, cane and sugar yield of ratoon crop of sugarcane in calcareous soil.

Wireworms in Florida Sugarcane

Wireworms, the larval stage of a click beetle, often cause severe damage to numerous crops in Florida. At least twelve species of wireworms have been found in southern Florida, but only the corn wireworm, Melanotus communis, is considered to cause significant economic damage to sugarcane. Since M. communis is the important wireworm species, the rest of this document will pertain to this species. Generally, wireworms are a pest of newly planted sugarcane and only rarely a pest in ratoon sugarcane. More studies are needed, but the current information suggests substantial percentages (e.g. 40% or more) of wireworms could be killed by flooding but, in general, the flood duration had to be at least 4 to 5 weeks at water temperatures above 24 °C. Soil insecticides are generally used in newly planted sugarcane for wireworm control. Insecticides are not used for wireworm control in ratoon sugarcane. Pheromone traps are untested in Florida sugarcane for click beetles but have an important function in for both mass trapping and monitoring in other agricultural systems.

Quantitative Proteomics Analysis of Sugarcane Ratoon Crop Chlorosis

Sugarcane is the most important sugar and bioenergy crop. Sugarcane ratoon crop chlorosis, caused by deficiencies of Fe, Ca and Mg because of low soil pH and excessive absorption of Mn, is a major crop production constraint in China and reduces cane yield as much as 40%. The molecular basis of the ratoon crop chlorosis is little understood. In this study, we employed TMT-labeling quantitative proteomics approach to study the proteins associated with sugarcane ratoon crop chlorosis using chlorotic leaves collected from the field. An in-house transcriptome database for sugarcane leaf was also constructed. From the proteome database, 7480 sugarcane proteins were identified; among them, 199 and 80 were found to be up- and down-regulated by the chlorosis. By functional characterization and protein–protein interaction studies, we were able to identify the components and pathways that might play a role in sugarcane chlorosis response. In addition to genes associated with photosynthesis, drought-responsive and jasmonic acid biosynthesis genes were also found to be associated with ratoon crop chlorosis in sugarcane. Data obtained in the presented study provide the molecular details of sugarcane ratoon crop proteome response during chlorosis.

A transcriptomic analysis of sugarcane response to Leifsonia xyli subsp. xyli infection.

Sugarcane ratoon stunting disease (RSD) caused by Leifsonia xyli subsp. xyli (Lxx) is a common destructive disease that occurs around the world. Lxx is an obligate pathogen of sugarcane, and previous studies have reported some physiological responses of RSD-affected sugarcane. However, the molecular understanding of sugarcane response to Lxx infection remains unclear. In the present study, transcriptomes of healthy and Lxx-infected sugarcane stalks and leaves were studied to gain more insights into the gene activity in sugarcane in response to Lxx infection. RNA-Seq analysis of healthy and diseased plants transcriptomes identified 107,750 unigenes. Analysis of these unigenes showed a large number of differentially expressed genes (DEGs) occurring mostly in leaves of infected plants. Sugarcane responds to Lxx infection mainly via alteration of metabolic pathways such as photosynthesis, phytohormone biosynthesis, phytohormone action-mediated regulation, and plant-pathogen interactions. It was also found that cell wall defense pathways and protein phosphorylation/dephosphorylation pathways may play important roles in Lxx pathogeneis. In Lxx-infected plants, significant inhibition in photosynthetic processes through large number of differentially expressed genes involved in energy capture, energy metabolism and chloroplast structure. Also, Lxx infection caused down-regulation of gibberellin response through an increased activity of DELLA and down-regulation of GID1 proteins. This alteration in gibberellic acid response combined with the inhibition of photosynthetic processes may account for the majority of growth retardation occurring in RSD-affected plants. A number of genes associated with plant-pathogen interactions were also differentially expressed in Lxx-infected plants. These include those involved in secondary metabolite biosynthesis, protein phosphorylation/dephosphorylation, cell wall biosynthesis, and phagosomes, implicating an active defense response to Lxx infection. Considering the fact that RSD occurs worldwide and a significant cause of sugarcane productivity, a better understanding of Lxx resistance-related processes may help develop tools and technologies for producing RSD-resistant sugarcane varieties through conventional and/or molecular breeding.

Estimated productivity of sugarcane through the Agro-Ecological Zone method

The estimate of the potential sugarcane productivity through agroclimatic models aids in the agricultural planning of the crops and the quantification of the yield for a given region. For these estimated values to be considered robust there is a need for validating the performance of such models in different areas and agricultural varieties. Hence, the aim of this study was to validate the Agro-Ecological Zone (AEZ) method with fifteen sugarcane varieties in the region of the Vale do São Patrício, state of Goiás, Brazil. We evaluated the data referring to the cane-plant (one-and-a-half-year sugarcane), as well as the first and second sugarcane ratoons (both with one-year cycles) in an irrigated and dry farming system. The productivities obtained in dry farming were corrected due to the occurrence of a water deficit in the crop. The results indicated that the AEZ method presented productivity estimates more satisfactory for the one-year cultivation cycles (ratoon cycles) for all varieties studied, with the model adjusting best to the CTC15 variety (RMSE = 8.70 t ha-1; MAE = 6.05 t ha-1; d = 0.99).

SUGARCANE BASE CUTTING QUALITY USING RECTANGULAR AND CIRCULAR BLADES

Sugarcane mechanized harvesting can lead to serious risks to the longevity of plantations when improperly operated, and may cause damages and disturbances in the remaining ratoons in the field. In this sense, this study aimed to evaluate the damage and disturbance to the sugarcane ratoons by the base cutting quality of two-blade models through statistical process control. The experiment was carried out during the 2015/16 growing season in an agricultural area of the Moreno Mill, located in Cravinhos, São Paulo, Brazil. The sugarcane harvester models A8800 (Machine 1) and BE1035 (Machine 2). The sugarcane variety cultivated in both treatments was SP80-1816. Thirty points were sampled per harvester, with 10-minute intervals between them. Equations were used to calculate the indices, which were then evaluated through descriptive analysis and statistical process control. Machine 2 presented process instability for the index of damages, with lower data variability. On the other hand, Machine 1 presented instability during the process due to the quality indicator and index of disturbance, but with a lower operation variability.

Intercropping in Sugarcane Improves Functional Diversity, Soil Quality and Crop Productivity

Intercropping of mustard or potato in sugarcane in relation to traditional non-intercropping rotation on microbial diversity, soil quality and crop productivity was assessed in a 3-year cropping system trial. The systems consisted of sugarcane + mustard–ratoon–cowpea (SmRC), sugarcane + potato–ratoon–wheat (SpRW) and a standard sugarcane–ratoon–wheat (SRW) rotation. The SpRW system recorded a significantly higher cane equivalent yield (120.4 t ha−1) than SmRC (109.4 t ha−1) and SRW (92.6 t ha−1), which was 10.1% and 30.0% greater, respectively. However, the highest microbial activities (microbial counts, microbial biomass carbon and nitrogen and basal soil respiration), soil enzymes, total carbon (TC) and nitrogen (TN), available N, Zn, Cu, Fe and cation exchange capacity (CEC) were recorded for SmRC system. The available K and S content were greater in SRW, while the highest average substrate oxidation rate was recorded in SmRC (0.00291 OD h−1), which was 14.1% and 7.58% more than that of SpRW and SRW systems, respectively. Moreover, SmRC significantly increased functional diversity indices and soil quality index. Total N, soil organic carbon, available P and S were identified as the key soil quality indicators, contributing 31.8, 30.9, 12.9 and 10.8% toward quality development, respectively. The highest functional diversity indices of microbial community, soil quality and crop productivity under intercropping are the result of greater SOC, TC, TN, microbial and enzymatic activities. In conclusion, intercropping of mustard or potato in sugarcane could be the way to increase crop productivity in limited land resources in subtropical areas of India.

Effect of cutting depth during sugarcane (Saccharum spp. hybrid) harvest on root characteristics and yield.

Ratooning is an important cultivation practice in sugarcane production around the world, with underground buds on the remaining stalk acting as the source for establishment of a subsequent ratoon crop. However, the optimal depth of cutting during harvest in terms of yield and root growth remains unknown. We carried out a two-year field study to determine the effects of three cutting depths (0, 5 and 10 cm below the surface) ratoon cane root and yield. Results showed that cutting to a depth of 5 cm increased the root fresh weight and root volume by 21–59% and 41–127%, respectively, compared to cutting depths of 0 and 10 cm. Remarkably, cutting to a depth of 5 cm also had a significant effect on the development of fine roots, which is closely linked to cane yield. The effect was particularly noticeable in terms of two root traits, root volume and the surface area of roots with a diameter of 1.0–2.0mm, and root length and the number of root tips in roots with a diameter of 0–0.5mm. As a result, a cutting depth of 5 cm below the surface increased cane yield by 43 and 28% compared to depths of 0 and 10 cm below the surface, respectively. Overall, these findings suggest that a cutting depth of 5 cm is optimal in terms of sugarcane yield, largely due to the enhanced effect on root traits, especially the development of fine roots. These findings will help optimize sugarcane ratoon management and improve the ratoon cycle.

Integrated Application of Ethrel and Microbial Consortia: Effect on Dry Matter Accumulation, Its Partitioning, and Nutrients Uptake in Late-planted Sugarcane Under Subtropical Indian Condition

Late (summer) planting of sugarcane is very much common in subtropical India. Due to the adoption of sugarcane–ratoon–wheat cropping system in the region, sugarcane planting is delayed. Delay in planting of sugarcane reduces the period of tillering. Thus to improve tillering, growth, and yield of late-planted sugarcane, a field experiment was conducted to assess the four levels of seed cane material (S1: conventional 3 bud setts, S2: sett soaking in water for 4 h S3: sett soaking in 100 ppm ethrel solution for 4 h and S4: foliar application of 100 ppm ethrel and mixture of 1% urea on seed cane, one week before planting) and two levels of NPK fertilizers with and without microbial consortia (M1: 50% of recommended NPK with microbial consortia (Pseudomonas fluorescens (phosphate-solubilizing bacteria) + Gluconacetobacter + Trichoderma); M2: Recommended NPK (150 kg ha−1, 25 kg ha−1, 50 kg ha−1 without microbial consortia). Foliar spray of ethrel increased total N uptake by 47.27% at the harvest stage (145.9 kg ha−1). An improvement of 36.40% in P accumulation was recorded with foliar application of ethrel on seed cane as compared to control during the tillering phase. However, P improvement in stalk increased to the level of 18.71 kg ha−1 at harvest stage. Foliar spray of ethrel accumulated 33.04% higher K than control (124.4 kg a−1) at harvest. About 26.16% improvement in individual cane weight was recorded with foliar application of ethrel. Thus, foliar application of ethrel improved sugarcane (73.15 t ha−1) and sugar yield (8.55 t ha−1). Integrated use of microbial consortia and 50% of recommended NPK could bring forth 9.85% (68.48 t ha−1) and 7.86% (8.10 t ha−1) improvement in sugarcane and sugar yields over the recommended NPK in summer-planted sugarcane in subtropical India.

Filter Cake as a Long-Standing Source of Micronutrients for Sugarcane

The aim of this study was to evaluate the residual effects of micronutrient application with or without filter cake on the supply of micronutrients, i.e., zinc (Zn), copper (Cu), manganese (Mn), iron (Fe), boron (B), and molybdenum (Mo), and sugarcane ratoon performance based on stalk and sugar yield. Two experiments were established in Sao Paulo state, Brazil, in a Rhodic Hapludox and a Typic Quartzipsamment in a randomized block design with an 8 × 2 factorial scheme. Seven micronutrient treatments (Zn, Cu, Mn, Fe, B, Mo, and all micronutrients) plus one control treatment combined with two filter cake rates (0 and 30 t ha−1) were applied in the planting furrow. Leaf micronutrient concentrations and stalk and sugar yields in the first, second, and third sugarcane ratoons were evaluated. The leaf concentrations of micronutrients were not affected by their application in the planting furrows but were affected by filter cake application. In addition, filter cake application increased stalk and sugar yields in both soil types and all ratoons. The micronutrients and filter cake applied in the planting furrow were able to supply micronutrients to sugarcane ratoons. The best plant response was attributed to B and Zn application, and a residual effect of filter cake application was observed in successive ratoons, with increased stalk and sugar yields.

Early Accumulation of Sucrose and Expression Behavior of Genes Associated with Sucrose Accumulation in Sugarcane Ratoon Crop Exposed to Gibberellin Influencing Source–sink Dynamics

The present study elucidates gibberellic acid (GA3) induced perturbation of source–sink communication to increase sink demand in winter initiated ratoon crop of two subtropical sugarcane varieties, viz., CoJ 64 and BO 91. The GA3-treated ratoon canes of both the varieties exhibited increase in internodal length by 10–15% (sink capacity), with a significant decrease in Brix (20.25%) and increase in reducing sugar (107.1%) in top internodes of BO 91. This has led to 14.44% decrease in total sugar in top internodes but an increase of 25.07% in bottom internodes compared with control. Expression patterns of sucrose metabolizing enzymes/genes, namely SAI, SuSy, CWI and SPS, augmented these results indicating increased sink strength and sink demand. In CoJ 64, the effect of GA3 treatment was not as pronounced as BO 91, possibly due to its early maturing nature that tends to increase inversion of accumulated sucrose beyond maturity period. GA3 treatment in ratoon crop of BO 91 indicated increased sink strength that would have influenced the high sucrose accumulation in this late maturing variety.