1 ABSTRACT CANE LOSS IN FIELDS HARVESTED WITH PUSBRAKE SYSTEM

Transcription

1 I Agricultural Engineering / CANE LOSS IN FIELDS HARVESTED WITH PUSBRAKE SYSTEM Melanie C. Morales and Victor J. Chavez, lnstituto Central de lnvestigaciones Azucareras, Casa Grande,Trujillo, Peru 1 ABSTRACT The study was conducted to determine the amouilt of millable cane existing in the field before and after the "braceo" (the last manual collection) and the amount of cane that is possible to pick up during the operation. Before the "braceo" there is an average of 3.8 ton/ha of millable cane or 1.95% of the net yield. The average loss of inillable cane is about 2.7 tons/ha or 1.47% of yield. During the "braceo" operation it was possible to pick up an average of tonslha. Forty-five % of the collected cane (before or after the "braceo") was crushed by the harvesting machinery. There is a directly proportional correlation of gross and net yield with amount of cane that is in the field before the "braceo". Quality variables show that cane crushed by the harvesting machinery loses quality in comparison with the cane that is not crushed. INTRODUCTION In Peru sugarcane is grown in about 85,000 ha, 50% of which use the mechanical cutting system called '"Push-Rake". The rest is cut by hand using rotary machine cutters which are still at an experimental stage. Sugarcane harvesting in the Agricultural Cooperative Casa Grande represents about 25% of the total cultivation of this type in the whole country and 45% of the total sugarcane that is cut mechanically. In this cooperative, harvesting is performed by using the Push-Rake system for both cutting and piling up cane, both operations carried out simultaneously. In this systern as well as in any other used by cane industry, losses of millable cane are found at several paints (~age6). Considering the two most important tendencies existing within mechanization of sugarcane harvesting, Push-Rake and rotative, it can be noticed that sugarcane losses have more often been studied in harvestings with rotative cutters than in harvestings with Push-Rake system. Such a situation exists because mechanical harvesting Push-Rake system requires adequate conditions and installations in order to separate extraneous matter carried with cane. Besides, Push-Rake is very often considered as a temporal harvesting means (Smith7). However, in some sugarcane 933

2 934 AGRICULTURAL ENGINEERING regims such as Peru and Hawaii, the characteristics of sugarcane cultivation as well as its growth habits necessitates'the use of mechanical harvesting system, especially for areas whose yields are above 170 tlha. In connection with cane loss, ~a~e6 said that it is necessary that the total losses of a system should not be higher than 5%, and that losses of 4% with Push- Rake system and 5.5% with harvesting rotary system are acceptable and reachable loss levels. The latter lcss is distributed as follows: 1.5% during cane cutting; 0.5 % during cutting of sugarcane top; 1.5% during ventilation; 0.5% during transhipment; and 1.5% at the storing center. ~errizuela3 studied cane losses using several rotary harvesting machines in fields of 60 to 80 tlha. He found losses of 4.4% and 6.8% when two types of integral harvesters were used; 4.7% when a combination of cutterand piler was used; and 1.3% when a combination of cutter and piler was used while the cutting off and piling were made by hand, loading being mechanical. On the other hand, Furlani Net05 said that increases of advance speed of harvesters raised the loss of cane in the field. He found that in a field of 87 tlha the average loss with speed machines is 2.28 tlha; with regular speed machines 3.24 t/ha; and with high speed machines 4.81 tlha. A very important feature of rotary harvesters is the efficient cutting off they can get. This is done by cutting with circular knives or by a pneumatic separation (~errizuela3). In his study about stripping tools, Brit02 reported that losses of profitable cane parts during the process of stripping depend on the uniformity of cane height or variation coefficient and the degree of the plant erection; and concluded that on art average a stripper works efficiently in fields with a variation coefficient of V < 20%. This machine gets an efficient elimination of sugar cane tops of 45% with losses of 1.8%. According to Clayton et ai4, and Cochran and Clayton (in ~errizuela3), pneumatic separation Is not very efficient because specific weight of stalk is almost the same at their lower and upper part. However, Abreaul introduced some changes in pneumatic separation system of KTP-1 harvester and increased the efficiency of this system by 22% thereby reduciog the total loss to 3%. The present research intends to evaluate the amount of sugarcane that is left in the field before the "braceo" operation (the last manual collection), the amount of sugarcane that is possible to pick up during the "braceo" operation and the amount of cane that definitely remains in the fields harvested with Push-Rake system. METHODS AND MATERIALS The harvesting system in Casa Grande included the following operations: a. Preparation of the fields for harvesting - This includes operations such as levelling of streets, retilling of drains, etc. that allow the harvesting

3 - - - I M. C. MORALES AND V. J. CHAVEZ machine to get into the fields as well as burning. b. Simultaneously cutting and piling -- Through the use of transcavators of tires models 988 and with a Hawaiian model cutter (Push-Rake). -. C. Loading in transportation - Loading is done mechanically by using hook cranes and a tearn of three people (gatherers) on trucks (trailers) with two cane carts, each with a capacity of 30 tans. d. Chopping ("repique") - This consists of cutting by hand the canes that remain on the field. These caries are placed across the furrows to pile them up more easily by means of a 950 transcavator equipped with a cutter like instrument. For chopping 2.3 shifts ("tareas") /ha are ernployed for a quantity of cane in the field that varies between 10 and 15 t/ha. e. The "braceo" - Once chopping is over, some canes still remain on the ground and for this reason a second and last gathering is made by hand. This operation of gathering is called "braceo" and canes gathered in this way were also piled by using a 950 transcavator. For this operation an average of 1.5 shifts ("tareasu)/ha are needed. f. Data - Plots for harvesting were chosen randomly. This was done immediately before and after the "braceo" operation. Then in both cases all canes g~owing in each plot were picked up. Each plot was 720 m2 containing four furrows each 'i20 m long and 1.5 m apart. Cane collection was divided into two separate parts: collection performed at the head of the plot where loading took place (the last 8 m) and collection performed in the rest of the plot. The collected stalks were also divid6d: stalk parts crushed by the machines and complete stalk parts. Total weight, weight per each linear meter and quality analysis were collected separately. Twelve replications were performed before the "braceo" and 13 after this operation. RESULTS AND DISCUSSION The results obtained (Table 1) show that the yield of the plots where the repetitions were performed varies between 125 and 330 t/ha for gross yield and between 108 and 288 t/ha for net yield. Net yield (gross yield minus the percentage of extraneous matter) varies between 1 1 % and 15%. The total amount of canes existing in the field before the "braceo" has a variation rank of t/ha with a standard deviation of considering the average (3.301 t/ha) or a variation rank of % considering the net yield of the field with a standard deviation of 0.28 regarding the average 1.68%. Cane after the "braceo" (cane that is lost) varies from to t/ha, with a standard deviation of considering the average t/ha or it varies from 0.49% to 2.02% of net yield with a standard deviation of 0.36 regarding its average

4 GABLE 1. Gross and net yield and the amounts of cane collected before and after the "braceo" Gross Net Collected cane (tlha) % of Replication Yield Yield Net tlha t/ha Crushed Not crushed Total Yield Before the "braceo" Y1 Y2 XI X Average Standard deviation - After the "braceo" ' Q Average Standard deviation Difference of averages

5 I M. C. MORALES AND V. J. CHAVEZ 937 TABLE 2. Amount of collected cane per 100 m2 of the zone where loading takes place, Collected cane kg11 00m2 Replication Crushed Not crushed *Total, Converted to t/ha Before the "braceo" Average Standard deviation After the "braceo" Q Average Standard deviation Difference of averages "Cane collected in the 667 m2 that correqonds to a hectare wl~en the field has 120 m long furrows

6 AGRICULTURAL ENGINEERING Ms Crushed cane n Not crushed cane Before the "braceo" After the "braceo" Repetitions FIGURE 1. Correlation between gross and net yields with collected canes before and after the "braceo"

7 I M. C. MORALES AND V. J. CHAVEZ 939 Before the "braceo" 1 Crushed cane n Not crushed cane *. After the "braceo" Repetitions FIGURE 2. Percentages of fiber (A,B), humidity (C,D) and pol (C,F) of crushed cane and not crushed cane collected before and after the "braceo"

8 940 AGRICULTURAL ENGINEERING Collected cane before the "braceo", tlha Collected cane before the "braceo", tlha FIGURE 3. Percentages of brix (A,B), reducing sugar and purity (E,F) of crushed and not crushed cane collected before and after the "braceo" I 1.33%. Cane crushed by the harvesting machinery used is approximately 50% of the above quantities. In Table 2, it can be seen that the amount of sugarcane was picked up at the head of the plot (the last 8 m of furrows) where sugarcane was loaded per 100 m2 extension. It also shows the amount of sugarcane gathered in 667 m2, an extension

9 M. C. MORALES AND V. J. CHAVEZ I TABLE 3. Average amounts (tlha) of cane collected in the field before and after the! "braceo" I I Before the "braceo" Crushed Not crushed *Total. % I In the field At the head of the plot Total B After the "braceo" In the field At the end on the plot Total Difference that represents the loading zone corresponding to a hectare, with average furrows of 120 m long. These quantities plus the ones shown in Table 1 give the total amount of sugarcane existing in the field before and after the "braceo" (Table 3). I Table 3 shows the average amount of sugarcane both before and after the "braceo". These results indicate that in the field before the "braceo" there was a total amount of 3,825 tlha of cane divided into two smaller quantities: tlha (45%1 of cane crushed by the machinery and tlha (55%) of cane that was not crushed. After the "braceo" there was a total amount of tlha divided into 1,232 t/ha (45%) and (55%), respectively. This amount remains definitely and on an average represents 1.47% of net yield of the field. The difference represents the amount of sugarcane that was gathered during the "braceo", that is a total amount of tlha divided into tlha (47%) of crushed cane and tlha (53%) of complete cane. Correlations between gross yield (yl) and net yield (y2) with the amount of crushed cane, not crushed cane afid the total amount picked up in the field before and after the "braceo" were done (Fig. 1). There was a correlation for both yields only In the case of the total amount of cane picked up before the "braceo." In Figs. 2 and 3 are represented the values of the six quality variables for each of the replication, before and after the "braceo': These values indicate that:,

10 942 AGRICULTURAL ENGINEERING TABLE 4. Weights per linear meter (kglm) of crushed and uncrushed canes collected before and after the "braced" Replication On the furrow At the head of the plot Crushed not crushed Crushed not crushed Before the "braceo" Average Standard deviation After the "braceo" Average Standard deviation

11 I M. C. MORALES AND V. J. CHAVEZ There is more fiber (Fig. 2A and 2B) in crushed canes than in complete canes. This is a logical result because crushing causes loss of juice but the amount of fiber remains the same. The difference is bigger in cane picked up after the "braceo" because in this case cane remains longer in the field ~esulting to greater losses of humidity, The percentage of humidity (Fig. 2C and 2D) shows a situation which is contrary to what happened with fiber for in crushed cane there is an evident loss of cane juice (water). The percentage of pol (Fig. 2E and 2F) and brix (Fig. 3A and 3B) in crushed cane is bigger than in complete cane in most cases. This apparent contradiction is due tcr the fact that the small quantities of soluble solids in the juice lost by the effects of crushing look larger when they are expressed in percentage for there is a great loss of water. The percentage of reducing sugar (Fig. 3C and 30) is higher in crushed cane than in uncrushed cane, owing to the fact that crushing accelerates deterioration of sugarcane quality. Finally the percentage of purity (Fig. 3E and 3F) show that in general, quality of crushed cane is worse than quality of uncrushed cane. It is important.to say that in every variable the differences between crushed cane and uncrushed cane become bigger in cane picked up after the "braceo". This happens because in this case cane remains longer in the field. On the average the weights per linear meter of crushed cane are less than the ones not crushed. (Table 4). This is due to the fact that crushing causes losses of cane juice. There are individual values showing a higher weight per linear meter of crushed cane because intensive crushing causes extraneous matter to stick to cane stalks, and this is difficult to separate. CONCLUSIONS Before the "braceo" operation in the field there is t/ha of miilable cane, 45% of whicli has been crushed by harvesting machinery. This amount represents 1.95% of the net yield. The losses of millable cane caused by mechanical harvesting with Push-Rake system, that is to say sugarcane that remains in the field after the "braceo", are about t/ha, 45% has been crushed by the machinery. This amount on an average represents 1.47% of the net yield., During the "braceo" operation an average of t/ha of cane is collected, 47% of this cane has been crushed by the machinery. There is a directly proportional correlati~n of gross and net yield with amount of sugarcane existing in the fields before the "braceo" or last collection by hand. Quality variables show that

12 944 AGRICULTURAL ENGINEERING sugarcane was crushed by harvesting machinery, because cane mixed with extraneous matter, has less quality than the one that has not been crushed. REFERENCES 1. Abreau, C.J. (1974). Pneumatic removal of extraneous matter by sugarcane harvesters. Proc. ISSCT 15(2): Brito, M.J. and J.C. Abreau (1975). Evaluacion del trabajo de 10s aparatos cortagollos de las cosechadoras de cana. Cuba Azucar. Eiiero/Marzo 1975: 3: Cerrizuela, E. (1976). Mecanizacion de la cana de azucar. Tecnologia No. 1. GEPLACEA. 63 p. 4. Clayton, J., W.C. Hedrick, Jr. and G. Franks (1974). Air velocities required to convey sugarcane stalk and leaf trash in a vertical stream. Proc. ISSCT 15(2): Furlani \Veto, V.L. (1977). Ensaio preliminar con colhedora de canade acucar Massey-Fergunson 201 cane commander, Brasil Acucariero, XC, 2: Lage, M. (1973). Algunas ideas sobre la mecanisacion y limpieza en la cana de azucar. Cuba azucar, Julio/Setiembre 1973~ Smith Dudley (1969). Field mechanitarion. Sugar y Azucar 64(11): PERDXDAS DE CARA EN CAMPOS COSECHADOS POR SISTEMA DIE PEINE M. C. Morales y V. Chaves Jr. Esta investigacibn se llevb a cab0 en la Cooperativa de Agricultura Casa Grande, Valle Chicama, Costa Norte del Peru. El proposito fui: determinar la cantidad de, caiia para molienda existe.lte en el campo antes del "braceo" (ultima recoleccibn manual), despues del "braceo " (perdidas) y la cantidad que es posible recolectar durante esta operaci6n. La recopilacion de informacion del cmpo consistio en recolecciorn total repetidamente de caiia existente en el campo, antes y despuks del "braceo", la operacibn se llevb a cab0 en parecelas de 720 m2 escogidas al azar. A la misma vez la porcion de tallos

13 M. C. MORALES AND V. J. CHAVEZ 945 triturados por equipo de cosecha fue separada de 10s no triturados y se Uevo a cab0 por separado un analisis de calidad de cada uno. \ Los resultados mostraron que previo.al "braceo" existe un promedio de t/ha de caiia para molienda o sea 1.95% del,rendirniento neto. La perdida promedio de cafia para molienda es de alrededor de t/ha o 1.47% del rendimiento. La operacion del braceo es posible recoger en promedio t/ha 45% de la cafia recolectada (antes o despues del "braceo") es triturada por el equipo de cosecha. Existe una correlacih proporcional directa de rendimientos bruto y net0 con la cantidad de cafia existente en el carnpo antes del "braceo". Las variables de calidad demuestran que la cafia triturada por equipo de cosecha pierde en calidad en comparacibn con la cafia no triturada.