Drip Fertigation –A Sustainable Water and Nutrient Management

World Hunger Map of 2020 states that number of hungry peoples will be 840 million by 2030. To cope up with this food demand, improvising agriculture with same resources will be one of the possible ways. In agriculture, all the metabolic functions of plant require optimum water and nutrients for higher productivity. 

A huge share of water is engaged in agriculture but recent progress and industrialization has reduced this share. Water resources in the world are either dropping or contaminated by industrial waste discharge. A large cost in agricultural productivity is of fertilizers which are applied into farm to get higher yield. These both factors are recent limiting factors to the farmers. Therefore, the present need is to attain maximum production with resourceful use of a drop of water with unit amount of nutrient. 

Drip irrigation system is universally adopted technique to efficiently use water resources. It reduces water utilization up to 70% and improves yield up to 90% with maintaining health of soil. This technique is best suited to plants grown in rows in the area of water scarcity, hilly area and in sandy soil. Farmers are gaining best results of using this irrigation system but the restrictive factor is initial investment. If this method is pooled with the balanced liquid nutrient application then it is giving more rewards to farmers. This is known as fertigation system. It can also be combined with surface irrigation, sprinkler irrigation or drip irrigation. But best is to club it with drip irrigation what is known as “Drip fertigation”. It is pooled method of drip irrigation with standardized dose of nutrients for the specific crop. It is also in support of the slogan of “Pradhan Mantri Krishi Sinchai Yojana” i.e. “more crop per drop”. 

It overcomes the problem with surface irrigation and has number of advantages like, 

1. Less water usage 

2. Water and nutrient application directly in effective root zone

3. No leaching or loss of fertilizer

4. Fertilizers are synchronized with plant need according to type of crop and critical stage of crop growth

5. less spoiling of soil

6. Least weeds therefore less labour and energy requirement

7. No salinization of soil

8. In adverse conditions also; it is easy to supply fertilizer

9. A reduction in the cost of fertilizer with increase in the yield is the commercial benefit to the farmers as they are adding much cost in farming

10. Better yield and quality of product

Fertilizer tank contains the solution of fertilizer. The main irrigation line is sidetracked to this tank by creating a low pressure to add water in tank for optimum dilution. These tanks are available in market having different capacities ranging from 90-160 litre. Venturi pump creates a low pressure and leads to suction of fertilizer from a tank into drip irrigation system. It allows sucking of fertilizer solution 30-120 litre per hour. Fertilizer injection pumps are the simple diaphragm pump which sucks the fertilizer in amount proportional to the flow of the water. 

Factors effecting drip fertigation: 

1. Selection of fertilizer: A readily soluble fertilizers should be selected. It should be in specific quantity according to crop and its growth stage. 

2. Compatibility of fertilizer: A combination of fertilizers should be easy to mix without having problem of precipitation of insoluble salts.

3. pH of water: The pH of irrigation water should fall between 5.5-7.0. Higher pH may resist the availability of essential nutrients and lower pH increases the concentration trace elements in soil.

4. Frequency of irrigation: Irrigation should be done by considering soil and climate condition. Further the type of crop and stage of growth is most important to decide the frequency of irrigation.

Fertigation with drip irrigation reduces the required dose of fertilizer up to 50% with higher fertilizer use efficiency by the plants. Frequent irrigation will provide optimum moisture distribution for the crop to absorb nutrients. The frequency of irrigation is either weekly. Bi weekly or monthly and dose of fertilizer to be applied is dependent on type of crop and condition of soil for best results. Root formation and establishment is observed in the zone of irrigation so that there is maximum yield with minimization of leaching of nutrients below root zone. The distribution of water is found in the surroundings of dripper as the distance is increasing from that there is diminution in level of nutrition. Urea, Ammonium Nitrate, Ammonium Sulphate, Phosphoric acid, Mono Ammonium Phosphate and Di Ammonium Phosphate are the suitable fertilizer for this system. The nitrogen fertilizers are compatible to this system and help to maintain nitrogen level required for the plants. Potassium fertilizer when added in complex with other fertilizer then it has problem of precipitation due to salt formation. Maintenance of diffusion rate is possible solution to have utmost potassium use efficiency. As phosphorous is highly immobile in soil, for its uptake it is advisable to have increased frequency of irrigation to sustain high moisture level in root zone. Plants which are suitable to grow with drip fertigation system are enlisted in Table 1. 

Table 1. Plants suitable to grow by drip fertigation system 

A high installation and its maintenance cost are the only negative factors for this system. The subsidies provided by Government will be much helpful this case. A cultivation of nontraditional crops having high commercial value would be other alternative to cope with the costing. 

Success stories of farmers using Drip fertigation system: 

Minatai Visnu Jagtap – a lady farmer belongs to Pimpalgao Vasant,  District Nasik, Maharashtra (India). She has cultivated hybrid - coloured capsicum in the area of 0.4 ha. She has installed a drip fertigation system and followed the fertigation schedule as per the recommendation in average interval of 45 days. She has found a least infestation of disease as well as weeds and earned net profit of Rs.2.5 million per annum per ha. 

Mr. Sigicherla Chenna Reddy – a farmer from Lakkasamudram (Village), Talupula (Mandal), Anantpur (District), Andhra Pradesh, India. He has adopted drip irrigation system since long and further started to follow drip fertigation since 2014  for intercrops by supplying micro-nutrients also. This way he overcome the water scarcity and earned extra income for his family. 

Mr. Venkatesan- A banana farmer of Dharmapuri (District), Tamil Nadu, India. He has cultivated G-9 cavendish banana using drip fertigation system under state sponsored precision farming project and observed all the plants have same height with uniform banana bunches. 

References:   

1. Khan, J. Z. and Khan, N. M. (2019)  A Review on Drip Fertigation on Field Crops,  International Journal of Engineering Research & Technology, 8(11),pp. 722-729.

2. Biswas, B. C. (2010) Fertigation in High Tech Agriculture- a Success Story of a Lady Farmer, Fertiliser Marketing News, 41 (10),4-8. 

3. Muttanna, Murthy, L. and Raj, S. (2018) Inspiring Stories from Innovative Farmers, National Institute of Agricultural Extension Management (MANAGE), 31-32.