About 80 per cent of Pakistani farmers grow wheat every year. A majority of them have landholdings of up to five hectares. The crop covers about 40pc of the total cultivated area in the country.
Unfortunately, torrential rains hurt the crop at harvest time. According to press reports, 150,000 tonnes of the crop were lost owing to the recent hailstorms across Punjab. It will reduce the agricultural GDP. Furthermore, the meteorological department has forecast another spell of torrential rains in coming days.
Farmers are also going to face postharvest grain storage problems throughout the country because of traditional methods used for seed storage.
The State Bank of Pakistan (SBP) says 16 million tonnes of wheat need proper storage facilities. Assuming an overall 15pc loss in cereals, it is estimated that Pakistan is annually losing as much as 5.6m tonnes of cereals worth $1.7 billion and 2.1m hectares of cultivated land resources.
According to the Food and Agriculture Organisation (FAO) of the United Nations, our economy loses Rs6-7bn ($76-90m) every year because of inadequate wheat storage facilities. Improper storage along with erratic rainfall and the upcoming monsoon cause additional losses in grains.
Pakistan loses $76-90m every year because of inadequate wheat storage facilities
Media reports indicate that wheat stocks in the warehouses of the Pakistan Agricultural Storage and Services Corporation (Passco) and provincial food departments were partly damaged by heavy rains last year. This occurs at the cost of the farmers’ poor-quality carryover seed and expensive production as 65-75pc of produced wheat is stored at farms. Farmers should avoid the storage of moist bulk seeds and never expose grain to humid air.
High humidity is the main reason for the loss of quality in wheat during production and storage stages. Another upset was the decline in the crop’s yield because of the yellow rust attack. Late sowing owning to the prolonged humid weather did not help either.
The quality of produce was compromised because of high seed moisture contents at harvest time. Wheat is harvested at 10pc seed moisture contents every year and remains safe from insects and fungus if stored properly. But the existing weather conditions, such as a high relative humidity (RH), will raise seed moisture contents, making the produce more vulnerable to insect and fungal infestation during storage.
Wheat requires about 12pc moisture content and 65pc RH for safe storage. The seed moisture content of greater than 14pc will promote mold attack that results in aflatoxin contamination of stored products. The presence of aflatoxin in grain poses a major risk for humans, especially children, as it can have immunosuppressive, mutagenic and carcinogenic effects.
This necessitates appropriate safe storage conditions to reduce the burden on the economy by avoiding wheat imports.
Reducing the moisture content and temperature during storage increases the longevity of seeds. Cold storage seems impractical because of expensive and inconsistent electricity supplies. The most viable approach can be the dry-chain technology, which means the drying of seeds and grains at appropriate moisture contents through either natural or artificial means after the harvest, followed by hermetic packaging to keep the product dry until its use in the value chain.
This relatively simple procedure largely prevents or mitigates post-harvest losses in dry commodities. In dry areas and seasons, seeds of staple crops can be dried in the field and packaged in hermetic bags to prevent moisture absorption during high humidity periods, particularly in the monsoon season.
Different international companies market hermetic bags. These bags are made from multilayer, recyclable polyethylene plastic with a proprietary barrier layer and sufficiently low permeability to prevent the exchange of air and the absorption of moisture. The use of modern hermetic storage technologies is limited in Pakistan. These storage methods preserve grain in a flexible system and create unfavourable conditions for pests and fungus development.
The University of Agriculture in Faisalabad has developed cost-effective hermetic Anaaji bags and drums that are useful for the storage of cereals, oilseeds and pulses and do not affect seed and grain qualities.
An Anaaji drum is a hermetically sealed plastic drum having a capacity of 160 litres. It can prevent both moisture and oxygen and thus reduces storage losses. A hygrometer is attached with it to monitor moisture contents of seeds indirectly by measuring equilibrium RH inside the drum.
An Anaaji bag is an improved multilayer hermetic grain storage technology, which requires no fumigation or chemical application. It preserves the quality and germination capacity of stored seeds. A humidicator strip is kept inside the bag to monitor the RH of the product. It can store grains and pulses for over a year without any gain or loss in moisture, insect pest infestation and fungal growth.
This pesticide-free organic storage monitors seed moisture contents and does not require any equipment or energy input. It preserves the quality and germination capacity of stored grains, oilseeds and pulses.
Last year, hermetic bags and drums were distributed among farmers in Sindh and southern Punjab. By adopting such technologies, formal and informal seed sectors can contribute to the country’s agriculture sector and ensure more quality seeds for the next growing season.
The writer teaches at the University of Agriculture, Faisalabad
Published in Dawn, The Business and Finance Weekly, July 8th, 2019