Reducing Paddy Post Harvest Losses


Postharvest  lossess  (PHL)  of  paddy  can  be defined  as  losses  that  occur  due  to  spills, human negligence and incompetence during the postharvest handling operations, inefficient processing system  that  results  in  broken  rice  and  improper storage  resulting  in  unpleasant  odours,  discolouration and insect attacks. Postharvest losses of paddy can be measured quantitatively and qualitatively. Reduction in PHL  of  paddy  is  necessary  to  increase  Malaysia’s  rice self-sufficiency level (SSL). Currently,  the  SSL  of  rice  is  71.5%,  while  the  rest is  imported.  In  1985,  Malaysia  produced  about  1.95 million metric tonnes of paddy with PHL of about 28.5% which was estimated at 557,000 metric tonnes resulting in a revenue loss of RM276 million based on the paddy price at RM496 per metric tonne. The high amount of losses prompted MARDI to conduct a study to determine the causes of PHL and proposed solutions to reduce it.

The study began in 2015 and covers all the postharvest handling  chain  including  harvesting,  transportation, drying,  milling  and  storage.  The  study  was  conducted in  the  granary  areas  such  as  the  Muda  Agriculture Development  Areas  (MADA)  in  Kedah,  the  integrated agriculture  development  areas  in  Terengganu  (IADA KETARA)  and  the  Kemubu  agriculture  development areas (KADA) in Kelantan. In 2015, Malaysia produced about 2.6 million metric tonnes  of  paddy  and  the  PHL  was  reduced  to  about 9.97%. However, this still resulted in a loss of 259,000 metric tonnes of paddy valued at about RM311 million based  on  the  current  price  of  paddy  at  RM1,200  per metric tonne.


Paddy  PHL  during  harvesting  are  caused  by  poor performance  and  condition  of  harvesters  used  during the harvesting process resulting in imperfect cutting of paddy  stalks  which  contributes  to  spillage  during  the process. There are two types of paddy harvesters used in Malaysia, namely, tangential flow and axial flow. Study on comparison of the PHL caused by these harvesters is still ongoing. However, improvement in the technology used resulted in the reduction of harvesting loss from about 9.0% in 1985 to 4.9% in 2015.


The  main  causes  of  PHL  during  transportation  are imperfect  and  unsuitable  conditions  of  lorries  while transporting  the  paddy.  Losses  occurred  along  the transportation chain, i.e., during transferring of paddy from the harvester to the lorry, transporting of paddy to the central collection areas, management and control of paddy in the central collection areas and transporting of paddy from the central collection areas to the milling plant. The baseline losses of paddy in the transportation chain  from  paddy  fields  up  to  the  milling  plant  was 6.0%,  while  the  losses  during  transportation  chain  in 2015 was 1.10%. There was a decrease of 4.9% in PHL due to the introduction of a good, sealed transportation system.  In  addition,  proper  handling  practices  during transportation  of  paddy  from  fields  to  factories  also reduced the rate of losses


Losses  during  drying  started  from  the  collection  of wet  paddy  before  being  dried.  The  losses  can  be  due to  delays  in  the  drying  process  after  harvest,  spillage during mechanical loading of paddy into the dryer, the use of high temperatures during the drying process and spillage during the transfer process out of the dryer. The dry  paddy  quality  in  terms  of  percentage  of  head  rice yield, broken rice and milling recovery is also considered in determination of PHL during drying. Losses in paddy drying were found to be insignificant (0.37% in 2015) in comparison to the basic data of 3.50% in 1985.

Milling and Storage

The paddy PHL during milling can be divided into two elements, i.e., poor handling and machinery inefficiency. Poor  handling  during  the  milling  process  resulted  in a  lot  of  spillage.  Inefficient  machineries  incur  losses during the process of husk and bran removal and rice grading. Spillage occurs during the transfer activities in each process (due to inefficient conveyor belts). Losses during storage are mainly due to the reduction in the rice quality such as discolouration which is affected by the storage technique. There is greater reduction in quality when rice is stored in commercial stores in comparison to hemetic or airtight storage. Insect attack is another factor which  reduces  rice  quality  and  quantity  during  storage. Postharvest  losses  during  storage  are  measured  by  the physical quality of the paddy and the number of insects present in a unit area. The baseline losses for milling and storage are about 10.0% in 1985 and 3.6% in 2015.

By: Dr. Azman Hamzah – Engineering Research Centre, MARDI
More at: Scientia MARDI – Vol. 009


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