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Smart Fertilizers as the Best Option for Ecofriendly Agriculture

Dr. M. Ranjith1* and Dr. S. Sridevi2

*1Research Associate, ICAR-Central Research Institute for Dryland Agriculture

Santoshnagar, Hyderabad, Telangana state 2Principal, Agricultural Polytechnic, Tornala, PJTSAU, Siddipet, Telangana State

Corresponding Author

Dr. M. Ranjith

Email: ranjithagrico34@gmail.com

Keywords

Smart fertilizers, Slow release fertilizers and Ecofriendly agriculture

How to cite this article:

INTRODUCTION

griculture plays a pivotal role in the

Indian economy. India holds the

second largest agricultural land (179.9

million ha) and agriculture accounts for 13.7%

of the GDP and provides employment to 56%

of the Indian workforce (Indiastat.com). Thus

agriculture not only contributes to overall

growth of the economy but also reduces poverty

by providing livelihoods and food security to

the majority of the population in the country

and thus it is the most inclusive growth sector

of the Indian economy. During the green

revolution period, new varieties were created to

produce higher yields in conjunction with the

intensive use of chemical fertilizers and

irrigation (Bowonder, 1979). The amounts of

A

ABSTRACT

As world population increase, there will be increasing pressure on global food systems and

agriculture. In the coming days, will have the challenge to providing sufficient food for a

growing population without impacting the environment will be a challenge. Accordingly,

it will be imperative to use modern technologies in agro ecosystems in order to supply

adequate food and minimize the negative impacts on the environment induces by chemical

fertilization and by inadequate recycling of farm wastes. There is an urgent to revolutionize

the agricultural systems with combination of biotechnology and nanotechnology and find

sustainable solutions for current and future problems. These include the development and

use of smart fertilizers with controlled/slow nutrient release, together with bioformulations

based on bacteria or enzymes. The importance of smart fertilizer development and use in

future food production and advances in the development of slow/controlled released

fertilizers and use of harvesting residues as coating and carrier materials for ecofriendly

agriculture are discussed in this article.

OPEN ACCESS

Ranjith, M. and Sridevi, S. 2021. Smart Fertilizers as the Best Option for Ecofriendly Agriculture.

Vigyan Varta 2(1): 51-55.

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chemical fertilizers used post-advent of the

green revolution continued to increase (Fig. 1).

The overuse of chemical fertilizers to get high

yield causes physical and chemical degradation

of the soil by altering the natural microflora and

increasing the alkalinity and salinity of the soil

(Singh, 2000).

Fig: 1. Consumption of fertilizers (N, P and K)

post-green revolution period (DAC & FW,

2017)

Returns from investment on fertilizer have been

declining over time, even as the cost of

fertilizers and crop production overall are

escalating. It has become more important than

ever befor to use chemical fertilizers

judiciously and to explore innovations related

to smart fertilizer technology as a response to

food security concerns under growing global

population and the environmental impacts of

current agricultural systems. Smart fertilizers

may be a solution to enhance food production

and environmental quality.

Slow/controlled released fertilizers

According to Shaviv (2005): “The term

controlled - release fertilizer (CRF) became

acceptable when applied to fertilizers in which

the factors relating to the rate, pattern and

duration of release are well known and

controllable during CRF preparation.” Slow

release fertilizers (SRFs) involve the release of

the nutrient at a slower rate than is usual but the

rate; pattern and duration of release are not well

controlled. Microbially decomposed N

products, such as urea-formaldehydes, are

commonly referred to as slow-release

fertilizers, and coated or encapsulated products

as controlled-release fertilizers (Trenkel, 1997).

The possible delay in initial availability of

nutrients or consistent supply for extended time

periods is achievable through a number of

mechanisms. These mechanisms include semi-

permeable coatings for controlled solubility of

the fertilizer in water, protein materials,

occlusion, chemicals, slow hydrolysis of water

soluble compounds of lower molecular weights

and some other unknown means (Naz and

Sulaiman, 2016). Many coating materials can

be used to slow nutrient release, including

natural materials such as clays and nanoclays

(e.g., allophane) and nondegradable

(polysulfone) and biodegradable polymers

(e.g., alginate

beads). Several studies have shown that urea-

based coatings can have variable efficiencies

depending on the material used (Du et al.,

2006).

Fig: 2. Schematic representation of smart

fertilizer effects in soil-plant system

Bioformulations and Plant Growth

Promoting Rhizobacteria (PGPR)

Plant growth promoting rhizobacteria (PGPR)

are a heterogeneous group of bacteria that can

be found in the rhizosphere, at root surfaces and

in association with roots, which can improve

the extent or quality of plant growth directly

and or indirectly. The exact mechanisms by

which PGPR promote plant growth are not fully

understood, but are thought to include (i) the

ability to produce or change the concentration

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of plant growth regulators like indoleacetic

acid, gibberellic acid, cytokinins and ethylene

(ii) asymbiotic N2 fixation (iii) antagonism

against phytopathogenic microorganisms by

production of siderophores, antibiotics and

cyanide (iv) solubilization of mineral

phosphates and other nutrients (Ahmad et al.,

2008). The environmental factors include

climate, weather conditions, soil characteristics

or the composition or activity of the indigenous

microbial flora of the soil. To achieve the

maximum growth promoting interaction

between PGPR and nursery seedlings it is

important to discover how the rhizobacteria are

exerting their effects on plant and whether the

effects are altered by various environmental

factors, including the presence of other micro-

organisms (Bent et al., 2001). In the last few

decades, a large array of bacteria including

species of Pseudomonas, Azospirillum,

Azotobacter, Klebsiella, Enterobacter,

Alcaligens, Arthobacter, Burkholderia,

Bacillus and Serratia have been reported to

enhance plant growth.

1. Nano fertilizers

Nano fertilizers increase the nutrient use

efficiency by 3 times and also provide stress

tolerating ability. Irrespective of the type of

crop, nano technology can be used. Since nano

fertilizers contain nutrients and growth

promoters encapsulated in nano scale polymers,

they will also have a slow and a targeted

efficient release (Sadik et al., 2009). A nano-

fertilizer refers to a product in nanometer

regime that delivers nutrients to crops. For

example, encapsulation inside nanomaterials

coated with a thin protective polymer film or in

the form of particles or emulsions of nanoscale

dimensions (De Rosa et al., 2010). Surface

coatings of nanomaterials on fertilizer particles

hold the material more strongly due to higher

surface tension than the conventional surfaces

and thus help in controlled release. Delivery of

agrochemical substance such as fertilizer

supplying macro and micronutrients to the

plants is an important aspect of application of

nanotechnology in agriculture. Excessive use of

nitrogenous fertilizer affects the groundwater

and also causes eutrophication in aquatic

ecosystems. A disturbing fact is that the

fertilizer use efficiency is 20-50 per cent for

nitrogen and 10-25 per cent for phosphorus.

With nano-fertilizers emerging as alternatives

to conventional fertilizers, build-up of nutrients

in soils and thereby eutrophication and drinking

water contamination may be eliminated. In fact,

nano-technology has opened up new

opportunities to improve nutrient use efficiency

and minimize costs of environmental protection

(Manjunatha et al., 2016).

2. Use of Harvesting Residues for Smart

Fertilizer Formulations

Low-cost materials such as wheat straw are

abundantly available resources in current

agricultural systems (Jiang et al., 2012). These

harvesting residues contain lignin,

hemicelluloses, and cellulose (Hubbe et al.,

2010). Wheat straw contains surface carboxyl,

hydroxyl, ether, amino, and phosphate, which

enhance its reactivity and physicochemical

properties, useful in the preparation of

adsorbent materials for the treatment of

wastewater and slow-release fertilizers (Liu et

al., 2013). Xie et al. (2011) noticed the potential

use of wheat straw for the development of slow-

release N and boron fertilizers with water-

retention properties.

Harvesting residues, such as straw, may also be

used as feedstock for energyproducing

pyrolysis systems with biochar generation.

Considering its physicochemical properties,

carbonaceous materials like pyrogenic carbon

(biochar) have been widely used as soil

ameliorant with several applications in both

laboratory and field studies (Wiedner et al.,

2015). Biochar is obtained through pyrolysis of

agricultural or other lignocellulosic biomass at

temperatures ranging from 350°C to 700°C.

Biochar was found to increase the C

sequestration potential of soil through its high

stability and the reduction of native soil OM

mineralization (Naisse et al., 2015). The use of

biochar as carrier for smart fertilizers could be

highly beneficial, as it combines nutritional

benefits for plants with improvement of many

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other soil functions due to the addition of

biochar itself. In particular, biochar addition to

soils has positive effects on water-holding

capacity as well as C sequestration. However,

biochar properties vary widely depending on

feedstock and production conditions (Wiedner

et al., 2013).

CONCLUSIONS:

In order to meet sustainable development goals,

agricultural production needs to be increased

and the pollution and GHG emissions related to

farming activity need to be decreased.

Advances in the application of biotechnology

and nanotechnology have the potential to

facilitate improved nutrient management and

use efficiency in agroecosystems. Compared

with conventional fertilizers, smart fertilizers

such as slow/controlled release,

bioformulations and harvesting residue have

been shown to improve crop yields, soil

productivity, and lower nutrient loss. Several

materials such as clays, nanoclays,

nondegradable and degradable polymers, and

agricultural wastes are suitable for the

development of smart fertilizers by acting as

carrier matrices for nutrients and bacterial

inoculants. We suggest that organic wastes

occurring as harvesting residues in agricultural

systems should be used in the sense of a circular

economy to create innovative fertilizers from

natural materials, which are urgently needed to

ensure sustainable intensification of

agricultural systems.

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