Post-harvest losses or post-production losses affect quantity and quality at the expense of processors and rice consumers. The causes are too early or delayed harvesting, spillage, inefficient retrieval, processing factors, machine inefficiency, operators inability, decay and during storage and pest infestation. Figure 2. Show the potential causes of losses from the farm to the consumer.
Table 1. Losses of rice within the post harvest system. (Source, FAO)
|
Region and Country ASIA |
Total Weight Loss % |
emarks |
|
Bangladesh |
7 |
|
|
India
|
6 |
Unspecified Storage |
|
3-5.5 |
Improved Traditional Storage |
|
|
Indonesia |
6-17 |
Drying 2, storage 2-5 |
|
Malaysia
|
17-25 |
Central Storage 6, threshing 5-13 |
|
|
Drying 2, on-farm storage 5, handling 6 |
|
|
Nepal |
4-22 |
On-farm 3-4, on-farm storage 15, central storage 1-3 |
|
Pakistan
|
7 |
Unspecified storage 5 |
|
2-6 |
Unspecified storage 2 |
|
|
5-10 |
Unspecified storage 5-10 |
|
|
Philippines
|
9-34 |
Drying 1-5, unspecified storage 2-6, threshing 2-6 |
|
up to 30 |
Handling |
|
|
3-10 |
Drying 1-5, central storage 6.5, threshing 2-6 |
|
|
Sri Lanka
|
13-40 |
Drying 1-3, on-farm storage 2-6, milling 2-6 |
|
6-18 |
|
|
|
Thailand
|
8-14 |
parboiling 1-3 |
|
12-25 |
On-farm storage 1.5-3.5, central storage 1.5-3.5 |
|
|
|
On-farm storage 2-15, handling 10 |
Awareness of post-production losses came with the initiation of HYV. Traditional technologies were not sufficient for the increased volume of harvested rice, and handling wet season crop was a new experience. Loss assessment studies mounted by various agencies reveal in almost all the rice growing countries in Asia, alarmingly large loss figures. The conditions, which caused these losses, are not given in the summaries. For example, in V. Gayanilo's study team (UPLB, Philippines), the field losses are actual physical grain loss measurements of grain that shattered or spilled. These numbers are projected as losses based on potential yields. Storage losses may be calculated from samples where levels of pest infestation are measured. Drying and milling losses are usually derived estimates, or comparative figures from control samples processed in the laboratory. When reading loss figures, remember that loss assessment results are specified to location, environment, technology, and procedures and are based on sample statistics. Unless field, environmental and processing plant conditions are defined, comparisons and conclusions based on other studies may be misleading. It is unscientific to say that gross improvements in the system has occurred by comparing loss estimates done in the 1970's with those done in the 1990's without a common framework for the loss assessment studies. Reducing losses as a programme goal, or as a research project objective, requires controls to verify whether progress has been made or not. The objective of loss assessment studies is to identify the need to allocate resources to post-production research, and to indicate priority areas for research. In the words of Dr Phan Hieu Hien of Vietnam, loss assessment studies alone cannot reduce losses. He further states that rice losses are large anyway and cannot be ignored; the most pragmatic approach is to provide the appropriate technologies to minimize the losses.
