Simple, cheap irrigation systems

 By JAMES LARAKI

IRRIGATION simply means the supplying of water to land and crops, especially by means of specially constructed channels or pipes. 

In other words, it is the artificial way of making water available to crops during periods of inadequate rainfall. 

The main idea behind irrigation is to ensure your crops have the minimum water requirement. 

Irrigation is reported to be the central figure for agriculture for over 5000 years and is used in many countries. 

However, it is considered unnecessary in Papua New Guinea, as most areas have enough water all year round. 

There are a few places in PNG where some traditional irrigation systems are used, but in most areas, it is something unheard off and the people limited experience with. 

There are different types of irrigation systems available. 

They differ in how water is obtained from source and distributed. 

But the main goal of whatever system used is to ensure your field is flood uniformly with water so that all plants access their water needs. 

Modern irrigation systems are efficient and can supply a crop field uniformly with water. 

These systems can ensure each plant has the amount of water it needs; not too much and not too little. 

However, these systems are not suitable to recommend to our rural farmers as they could not afford them. 

But we cannot ignore it altogether. 

The likely drought events with the changing climate, requires us to explore simple irrigation systems available and demonstrated on-farm for possible adoption by the farming community when needed.

NARI, as part of its long term strategic preparedness, explored a number of irrigation systems suitable to our conditions and needs. 

Through a number of trials and observations, a number of water lifting and water distribution systems were selected for further testing and on-farm demonstrations. 

Among them is the Rope and Washer Pump. 

The rope and washer pump has been demonstrated around the country through various events such as NARI open day and field days, provincial shows, and at community resource centres. As the name suggests; a nylon rope, washers, a pipe and a pulley are required to construct this pump. 

As the pulley is rotated, the nylon rope is pulled up through the pipe. 

The washers attached to the rope pushes water to the surface. 

It can be easily constructed from locally available material and can lift water 20m high. 

It is suitable for pond, rivers and underground water sources. 

The selections of these systems were selected based on the following criteria:

• The system is cheap to set up and maintain. Parts or material is locally made or available;
• easy to operate and managed by almost everyone;
• system is suited to various types of water source;
• ability lift sufficient volume of water and pump is reasonably efficient;
• less labour required to set-up and use, and,
• The system is portable

Another factor to consider is water source. 

Water sources need to be easily accessed for these systems to be useful. 

Rivers and creeks are the main source of water. 

In most cases, many of the sources would have dried up during a drought period, so others have to be found. 

Wells can be dug in dry river or swamp beds. 

Areas with green grasses may indicate the presence of water. 

Once water is found, a water lifting system can be set up to feed the irrigation system.

While irrigation is not a necessity for now in most areas, it would be handy during a prolonged dry period. 

Such was the case in some vulnerable areas during the 1997/98 drought event. 

In any case, it is wise to include simple irrigation systems into any long term strategies towards drought preparedness.