71.7% in stalk yield and 84.3% in sucrose yield over the V-furrow

Transcription

1 METHODS OF PLANTING SUGARCANE FOR SUGAR AND BIOMASS PRODUCTION IN LOUISIANA R. Ricaud and B. J. Cochran Agronomy and Agricultural Engineering Departments Louisiana Agriclrltural Experiment Station Baton Rouge, Louisiana, USA ABSTRACT Agronomy Experiments were conducted to determine the effects of methods of plantihg on the yield and yield components of sugarcane. Single and muljiple drill types of planting furrows were tested at widths of planting ranging from a V-furrow to 20 cm wide on standard row widths of 80 cm. Results indicated that the highest number of millable stalks and yield of stalks, sucrose, total biomass and fermentable sugars were produced from planting 4 drills, 90 cm wide with plant and stubble cane in one test and from 4 drills, 20 cm wide with plant cane in another test. The increases ranged up to 7.7% in stalk yield and 84.3% in sucrose yield over the V-furrow planting with plant cane. The highest yields produced were 78.6 tons of green weight and 40.0 tons of dry biomass per hectare and 5.3 tons of fermentable sugars per hectare with plant cane. Yields were increased substantially with wide single and multiple drill types of planting as compared to conventional V-furrow planting. INTRODUCTION Sugarcane is produced in Louisiana during a relatively short growing season due to climatic conditions. The crop usually grows from April until harvest time in October. Although cane grows rapidly during the summer and matures with a high sucrose content, the sugar yields are low due to short millable stalks and low cane yields. Variety developments have increased the sugar content, but have not appreciably increased the stalk yield of sugarcane. Pest management and fertilization technology has helped to maintain current yields., Previous work has indicated that sugarcane yields were closely related to the millable stalk population, especially in areas with a short growing season. Some cultural practices have been shown to increase stalk ~opulation and yield. Alternate methods of planting have the greatest potential to produce large increase in sugarcane stalk population and yield in Louisiana. The purpose of this paper is to present agronomic data obtained from experiments on 302

2 R. RICAUD AND B. J. COCHRAN- 303 methods of planting sugarcane. The machinery development research involving methods of planting will be the subject of another paper. MATERIALS AND METHODS Experiments were conducted to determine the effects of methods of planting on the yields and yield components of sugarcane for sugar and biomass production. The tests were located on a Commerce silt loam soil on the Louisiana Agricultural Experiment Statibn at St. Gabriel, La.Experiment I was initiated with plant cane in 977 and continued with first stubble cane in 978. Experiment 2 was initiated with plant cane in 978. The methods of planting studied involved the types and widths of planting furrows (Table ). The types of planting furrows or number of drills in each test were single and m~iltiple drills on standard rows 80 cm wide. In Experiment, the multiple drills were planted with one line of seed cane in each drill spaced 30 cm apart. The total widths of the single and multiple drill types of furrows were 30,60,90 and 20 cm. TABLE. Experiments conducted on methods of planting sugarcane on Commerce silt' loam soil at the Louisiana Agricultural Experiment Station, St. Gabriel, Louisiana in Experiment. Plant and stubble Experiment 2. Plant cane Drill Total Drill Total Treatment No. of spacing width No. of spacing width No. 9 drills (cm) (cm) drills (cm) (cm) The number and spacing of drills shown for each treatment was planted on rows 80 cm wide. In Experiment 2, the multiple drills were planted with one line of seedcane in each drill spaced 40 cm apart. The total widths of the single and multiple drill,s were 40, 80 and 20 cm. In both tests, the same amount of seed cane was planted in the single and multiple drills for each total furrow width. A standard V-furrow with one drill was planted as a check treatment in each test.

3 304 AGRONOMY The plots were 2.6 cm long and 3 rows wide with 4 replications of each treatment. Variety CP was planted in October and harvested in November of the following year in each test. Standard cultural practices were used after planting the cane. Yield and yield components were measured at harvest time on each plot. The plant number of population was determined by counting the millable stalks. The plant height, stallc diameter and individual stalk weights and the percentage of stalks, tops and leaves were measured on 20-stalk samples. The stalk yield was measured in the field by weighing the cane with tractormounted scales. The biomass yield was calculated from the plant weights and number of stalks per hectare. The sucrose content of the cane juice was measured by the polariscope method to calculate sucrose yield. The percentages of sucrose, glucose and fructose sugars were measured by the liquid chromatograph method to determine the yield of fermentable sugars. The stalk fiber yield was determined by washing and drying bagasse samples. Yield Components RESULTS AND DISCUSSION Results obtained on yield components in each experiment are reported in Table 2. The V-furrow treatment produced a significantly lower number of millable stalks at harvest than the other treatments in each test. In Experiment, with plant cane and stubble cane, the maximum number of stalks was produced with the 4 drills, 90 cm wide planting. The cane on the wider drills was damaged during cultivation and did not producb the highest plant population. In Experiment 2, the maximum population was proddcbd with the 4 drills, 20 cm wide planting. The plant height, measured at the last visible dewlap, increased in most cases with increasing width of drills and plant population. The differences in stalk diameter and weight due to the treatments were not significant. Stalk and sucrose yield Results obtained on stalk and sucrose yield in each test are reported in Table 3. The V-furrow treatment produced the lowest yield of stalk and sucrose in each test. In Experiment, the 4 drills, 90 cm wide planting prodiked the largest increases of 7.7% and 52.7% in stalk yield and 84.3% and 59.3% in sucrose yield over the V-furrow with plant and first stubble cane respectively. In Experiment 2, the 4 drills, 20 cm wide planting produced the largest increases of 45.9% in stalk yield and 4.9% in sugar yield over the V-furrow. The percent sucrose in the cane juice determined by the polarixope method was not significantly affected by the methods of planting. The stalk and sucrose yields were closely associated with the number of millable stalks per hectare.

4 R. RICAUD AND 8. J. COCHRAN 305 Total biomass yield ',?>- The data obtained on green and dry biomass yields in each test are reported in Table 4. The V-furrows produced the lowest biomass yield. In Experiment, the 4 drill, 90 cm wide plantiy produced a maximum yield TABLE 2. Effects of methods of planting on the yield components of sugarcanes No. of Width of drills Number Height Diameter Weight Exper., Plant cane, NS NS Exper., First stubble, 978 I I NS NS Exper. 2, Plant cane N S NS Measured at harvest time.

5 306 AGRONOMY TABLE 3. Effects of methods of planting on the stalk and sucrose yields of sugarcane. Stalk Sucrose Width of Juice No. of drills Yield I nc. sucrose Yield I nc. drills (cm) (Tonlha) (%) (%) (Tonlha) (%) LSD 5% 4 5 LSD 5% -- Experiment I, Plant Cane, 977 V J'.eT ' I NS. - Experiment, First stubble, 978 V N S Experiment 2, Plant cane, 978 V NS I Sucrose by polariscope method,

6 R. RICAUD AND a. J. COCHRAN 307 TABLE 4. Effects of methods of planting on the tatal biomass yield of sugarcane. Total yields Green yield in Width of No. of drills Green Dry Stalks Tops* Leaves drills (cm) (TIHa.) (%I Experiment, Plant cane, gt7 V LSD 5% Experiment, First stubble, 978 V I O LSD 5% I Experiment 2, Plant cane, 978 V O LSD 5%. 2.6 Total above-ground growth. 2 Tops were immature internodes. of 36.9 tons of green yield and 3.3 tons of dry yield per hectare in plant cane and 52.9 tons of green yield any,,$36.8 tons of dry yield per hectare in stubble cane. In Experiment 2, the 4 c~ijj!s, 20 cm wide planting produced the maximum yield of 78.6 tons of gree~j! yjeld 'and 40.0 tons of dry yield i s

7 308 AGRONOMY TABLE 5. Effects of methods of -planting on the fermentable sugar and fiber d yields of sugarcane. Width of Fermentable sugars Fiber No. of drills Stalk Juice Yield Stalk Yield drills (cm) (%) (%) (Tonlha) (%I (Tonlha) - Experiment, First stubble, 978 V q7, I , LSD 5% NS NS.O 0.7 Experiment 2, Plant cane, 978 V LSD 5% N S NS.2 -.O Sucrose, glucme and fructose sugars determined by the liquid chromatograph method per hectare. The difference in,percent stalks, tops and leaves due to the planting methods were small. The averhge percentages of stalks, tops, and leaves in the total green biomass were 77.4, :6 and 2.0, with plant cane in Experiment, 69.7, 4.4, and 25.9 with stubble in Experiment,and 69., 4.0. and 26.9 with plant cane in Experiment 2. The stalks consisted of the millable stalks topped at the last hard internode and the tops cohsisted of immature internodes.,,? - Fermentable sugars and fiber yield The data obtained on fermentable sugars by the liquid chromatograph method and the fiber content of the stubble cane in Experiment and plant cane in Experiment 2 are reported in Table 5. Differences in the percentages of fermentable sugars in the cane juice due to methods of plantifig were small. The average fermentable sugar contents in both tests were 5.% in the stalks

8 R. RICAUD AND 6. J. COCHRAN 309 and 7.4% in the juice. The sugars in the juice consisted an average of 6.2% sucrose, 0.7% glucose and 0.5% fructose. The sugar analyses were made on fresh cane when apparently 83.% of the sugars was in the sucrose form. The highest fermentable sugar yields produced were 4.6 tons per hectare from the 4 drills, 90 cm wide planting in Experiment and 5.3 tons per hectare from 4 drills,.520 cm wide planting in Experiment 2. The differences in percentages of fiber in the stalks were small. The highest yield of fiber per hectare was produced by the same types of planting that produced the highest sugar yields. Generally the results indicated that the stalk, biomass a~d sugar yields can be increased substantially in Louisiana with wide planting on conventional rows 80 cm wide. Four lines of seed cane per row planted 90 cm wide in either a single wide furrow or in multiple drills appeared to be the most practical method of planting to increase yield. This means that one-half of the surface area of,each row was actually planted, which allowed ample space between rows to operate cultivation and harvesting equipment. Cane growing in drills wider than 90 cm was easily damaged during cultivation and difficult to harvest mechanically. Single wide furrows can be planted with mechanical planters, but it is difficult to properly cover the seed cane with soil. Multiple drills must be planted with hand labor, but it is easy to cover the seed cane without squeezing the seed into a narrow drill. METODOS DE SEMBRAR CARA DE AZUCAR PAM LA PRODUCCION DE AZUCAR Y BIOMASA EN LOUISIANA R. Ricaud y B. J. ~ochran RESUMEN Se llevaron a cab0 experimentos para determinar 0s efectos de diferentes metodos de siembra sobre el rendimiento y 0s componentes de rendimiento de caiia de azucar. Se ensayaron siembras en hileras sencillas y multiples, variando desde un sucro en forrna de V hasta un ancho de 20 cm en hileras normales de '80 cm de ancho. Los resultados demostraron que el mayor rrumero de tallos aptos para el molino y rendimiento de tallos, sacarosa, total de bioma &/ a y azucares fermentables fueron producidos sembrando 4 hileq 90 cm de ancho con plantua y retoiio en una prueba y con 4 hilei 20 cm de ancho con plantilla en otra prueba. Los aumentos variar n hasta 7.7% en rendhiento de tallos y 84.3% en rendimiento P de sacarosa sobre la siembra en sucros en forma de V en plantilla. Los rendirnientos mas altos producidos fueron 78.6 toneladas de materia

9 - 30 AGRONOMY verde y 40.0 toneladas de biomasa seca por hectarea y 5.3 toneladas de azucares fermentables por hectarea en plantillas. Los rendimientos fueron aumentados substancialmente con siembras en hileras anchas y sencillas y multiples en comparacion con la forma convencional de sembrar en sucros en forma de V.