Assessment of Sugarcane Maturity for Optimum Sugar Yield

Khin Myint Kywe

Despite a high tonnage of millable sugarcane

the highest possible sugar yield is still

dependent on the degree of maturity of cane

plant at harvest time.

Hence it is essential to harvest the cane at peak

maturity. Preharvest maturity testing could

indicate the exact time to harvest.

Introduction

Sugarcane is considered to be mature or ripe

when the sucrose accumulation in the bottom

and top portion of cane stalk is about equal.

The ratio of the brix (soluble solids in cane

juice) of the top third of the stalk to the brix of

the bottom third approaches unity or nearly

unity when the cane is ripe.

This method is simple, rapid, and inexpensive

and still in wide use today.

Refractometer for testing sugar content

Maturity testing by Physiological Changes

Brix determination using a hand refractometer is the most reliable method of monitoring maturity in the field.

Brix is the percent solids in the cane juice which roughtly estimates sweetness in cane.

Maturity is indicated by a more or less uniform and high brix reading of the juice collected from the top, middle and basal portions of the stalk.

An immature stalk has high brix reading at the base and low at the middle and top.

The overmature cane registers high brix at the top and low at bottom

To determine the optimum time of

harvest for four sugarcane varieties

To minimize post harvest sugar

losses at fields/ cane centers /mill

yard.

Materials and MethodsThis study was conducted at the Pyinmana

Sugarcane Research Center ,Sugarcane Development

Department, Pyinmana, NayPyitaw, during October ,

2010 to January 2011.

4 sugarcane varieties were planted on 15th January

2010 in rows keeping one meter distance between

row to row and one feet distance from set to set.

Maturity test by using refractometer started from

15 th October 2010 to 30 th January 2011

Sampled cane of each test variety were selected

and brix reading of the juice collected from the top,

middle and basal portions of the stalk were recorded.

Procedure of Maturity Testing

3 millable stalk samples Weighted

Counting the internode Number

Divided three equal parts

Crushed separately by 3 roller laboratory

mill

Analyzed for brix of each part by hand refractometer

Calibrated withbrix hydrometer

Maturity Test results of four sugarcane Varieties

Sr.Record Date

Kps-94/13 K-88/92 K-95/84 K-95/283

    T M B T M B T M B T M B

1 15.10.2010 16.0 18.5 18.9 14.5 16.5 18.5 13.0 15.5 17.5 15.0 17.0 18.5

2 30.10.2010 16.3 19.0 20.0 15.0 18.0 19.0 13.5 17.0 18.0 15.0 17.9 19.1

3 15.11.2010 17.1 20.3 20.8 16.6 21.0 21.5 14.6 17.7 18.1 17.4 21.0 21.5

4 30.11.2010 20.8 20.8 20.9 17.5 18.5 19.75 18.0 19.5 20.5 18.5 21.0 21.7

5 15.12.2010 21 20.5 20.9 20.0 21.2 21.4 19.39 21.2 21.4 20.5 21.5 21.8

6 31.12.2010 21.5 20.0 20.3 21.0 21.3 21.5 21.0 21.3 21.5 21.5 21.7 21.9

7 15.1.2011 20.0 19.5 19.5 21.5 21.7 21.9 22.0 21.5 21.9 21.9 21.5 21.7

8 31.1.2011 19.5 18.5 19.0 22.0 21.0 21.5 22.0 21.6 21.7 22.0 21.7 21.7

Maturity Results of Different Sugarcane Varieties

Sr. Name Maturity Time

  of varieties  

1 Kps-94/13 End of November

2 K-88/92 Middle of December

3 K-95/84 Middle of December

4 K-95/283 Middle of December

Maturity Test results of Kps-94/13

Environmental conditions during studied period

Month Temperature(˚C) Rainfall

  Max Min (mm)

October,2010 33.36 23.96 210

November,2010 34.60 20.30 -

December, 2010 31.60 16.12 16

January,2011 30.77 14.44 50

During the period of maturity testing program rainfall was abundant on October, 2010 & continued to January, 2011.

The differences between maximum and minimum temperature were about 10 to 16 October to January

1. Harvesting is one of the critical operations in sugarcane farming and

untimely harvesting results in the loss of tonnage and sucrose content.

2. The ripening of sugarcane or actual accumulation of sugar starts from

the months of October to November.

3. Sugarcane crushing season in Myanmar starts between mid November

to end January.

Constraints and lessons learnt during implementation

4. Maturity testing of sugarcane varieties, therefore, used to start mid

October.

5. Although a perfect maturity state is theoretically attainable, in actual

practice, deviation from a nice fit of peak maturity point may be

expected due to unfavorable weather conditions and sampling

variation.

1. Sugar yield reduction from early & late season harvest

could be minimized by scheduling cane harvest in

order of degree of maturity & juice quality.

2. Rapid & accurate method of maturity testing is essential to

determine the harvest time for maximum sugar

production.

3. Fully mature cane will not deteriorate as rapidly as either

immature or over mature cane.

Recommendations

4. Present study was the evaluation of maturity of four cane varieties, other promising varieties need further testing.

5. To obtain the highest possible yield from sugarcane, the crop should be harvested when mature.

6. The peak sugar recovery was usually achieved in mid-December.