Water-soluble fertilisers are key to higher maize fodder yield and quality

The use of fertilisers is not merely about adding nutrients to the soil as there are myriad possibilities of what all could go wrong. 

Adding nitrogen-laden fertilisers to maize fodder crops  often increases biomass and crude protein levels in the forage. However, indiscriminate use of chemical fertilisers may contribute to nitrate accumulation in forage, a potent anti-nutritional component that may cause substantial livestock losses. 

Therefore, the recommended dose of fertilisers should be applied for quality fodder production, but the uneven distribution of fertilisers in the rhizosphere results in poor crop response, low fodder yield, and a decline in soil health as well as environmental impacts. 

A farm testing has already demonstrated that there is large field variability in soil nutrient supply, nutrient use efficiency, and crop response. 

Further, low efficiency in the use of fertiliser and resource impact fodder production costs with serious environmental consequences. Therefore, higher fodder productivity and input use efficiency will require more knowledge-intensive crop and nutrient management techniques tailored to specific characteristics of individual fields to manage field variability. 

WSF — a single stop solution

This is where water-soluble fertilisers (WSFs) come into the picture. 

WSFs can be used for a variety of field conditions by making their nutrients readily available for uptake and utilisation by crop plants. These fertilisers are 100 per cent water-soluble and have a low salt index. 

The WSFs are available in two forms, i.e., crystalline or liquid, and can be sprayed on leaves or mixing them in the irrigated water. 

They are available in various NPK formulations but may also contain secondary and trace nutrients like sulphur and zinc. 

Every formulation displays NPK in a standardised format, such as 19-19-19. 

The first number always refers to the percent nitrogen, the second expresses the per cent phosphorus in the oxide form (P2O5), and the last number represents the percentage of the oxide form of potassium (K2O). 

So far, 16 water-soluble fertilisers have been developed and included by the GOI in the Fertilisers Control Order, 1985 (Table 1). Crop nutrition management is easy through water-soluble fertilisers, as the nutrient levels are not affected by leaching, erosion, or evaporation.

In terms of merits and demerits of these fertilisers, firstly it’s important to consider the cost-efficiency of WSFs as  25-30 per cent of the recommended dose of fertiliser can be saved using water-soluble fertilisers. These are also suitable for soil application, depending on the requirements and additionally, various ranges of nutrient grades are also available. They also prevent the accumulation of salts in the soil. 

However, on the downside, sometimes water-soluble fertilisers can lead to nutrient overload, causing stress or damage to crop plants (phytotoxic injury) if they are improperly diluted or overapplied.

Testing the waters

Krishi Vigyan Kendra, Barnala, is working on water-soluble fertilisers to examine their economical feasibility in fodder production. 

An on-farm trial was conducted to evaluate the effects of water-soluble fertiliser NPK (19-19-19) application on maize fodder yield and its quality at various farmers’ fields in Barnala district of Punjab. 

Table 1: FCO-approved 100 percent water-soluble fertilisers

Table 2: Economical feasibility of water-soluble fertiliser NPK (19-19-19) for maize fodder production

There were three fertiliser management practices, i.e., farmer's practice, recommended dose of fertiliser (RDF), and NPK (19-19-19) foliar application at 1 per cent at 3 weeks after sowing with 75 RDF. Foliar application of NPK (19-19-19) at one per cent at 3 weeks after sowing with 75 per cent RDF increased plant growth in terms of fresh and dry weight of maize plants and productivity in terms of green fodder yield.

The nutritional status of fodder was also improved over the recommended dose of fertilisers and farmers’ practices. Our trials indicate that water-soluble fertiliser can reduce the fodder production cost and leaching, run-off losses of N, K, and P, as well as volatilization losses of N. This can also significantly reduce the wastage of nutrients and the financial burden faced by farmers in the form of input costs, mainly fertilisers in fodder production (Table 2).

Injudicious use of fertilisers can reduce nutrient use efficiency, crop response, productivity, and profitability. Contrary to this, water-soluble fertilisers, which lead to the balanced use of fertilisers while maintaining and improving soil health, may be considered promising agro-techniques to increase fertiliser use efficiency, restore soil health, and sustain fodder yields. Thus, water-soluble fertilisers can be an alternative source of nutrients in fodder production.

Views expressed are the author’s own and don’t necessarily reflect those of Down To Earth