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D. L. N. Rao et al.
1 Introduction
The major agricultural challenges in the developing world are ensuring food and
nutritional security, improving soil health and maintaining environmental quality.
Reduced organic waste recycling, low and imbalanced fertilizer use, not correcting
inherent soil constraints or emerging nutrient deficiencies are the major contributors
of poor soil health. Continued high fertilizer usage in post-green revolution era has
also brought sustainability concerns. The hotspots of N fertilizer application have
shifted from the USA and Western Europe in the 1960s to eastern Asia in the early
twenty-first century. Europe, China, and India now account for over 50% of the N
used [26, 54]. Together with the enhanced cropping of nitrogen fixing legumes, it has
led to an expansion of the reactive N pool in the environment [28]. Inefficiencies in
N uptake lead to significant N losses and associated environmental problems which
are likely to be compounded by global climate change. Over 3/4ths of nitrous oxide
emissions from Indian agricultural soils are from applied nitrogen fertilizers [67].
Low fertilizer nutrients use efficiency by crops, typically for N (30–50%), P (15–
20%), S (8–12%), Zn (2–5%), Fe (1–2%) and Cu (1–2%) [61] has been attributed
to deterioration in soil health and poor synchronization between crop demand for
nutrients and their availability from soil.
Traditional farming is based on local practices and improving the fertilizer use efficiency will require transition to precision farming, which combines sensors, robots,
drones, GPS, mapping tools and data-analytics software to customize the care that
plants receive [49]. Data on individual plants like stem size, leaf shape and the moisture of the soil around a plant is fed to computers, which analyses for symptoms
of stress and gives feedback to farmers in real time to deliver water, pesticide or
fertilizer in required doses only. In map-based VRA technology a map is generated
of the farm and fed into the computer on board that decides which fertilizer should be
applied in a given parcel of land and in what quantity. Precision farming efficiently
manages spatial variations in the field, reduces water and chemical use, and produces
healthier crops and higher yields-all of which improves farmers’ incomes, conserves
resources and reduces chemical runoff. However, there are several challenges that
limit its broader adoption: socio-economical, agronomical and technological. Precision farming technology has moderate risk-reduction benefits which lead to higher
profits in the long run due to decreased variability in yields in a field. Precision
agriculture (PA) is now being increasingly adopted in developed countries [37];
according to Molin and Tavares [58] about 15% of the grain producers in Brazil,
use PA techniques to apply inputs at variable rates based on soil characteristics. In
many developing countries with small size land holdings, other site-specific nutrient
management techniques and drip irrigation/fertigation may be more simpler and
economic alternatives that approach precision agriculture in efficiency.
There has been a worldwide upsurge on interest in organic farming. As of 2015,
India had the most organic producers followed by Uganda and Mexico. In 2018, India
was 9th in terms of land under organic agriculture [102] with 3.56 million ha under
D. L. N. Rao et al.
1 Introduction
The major agricultural challenges in the developing world are ensuring food and
nutritional security, improving soil health and maintaining environmental quality.
Reduced organic waste recycling, low and imbalanced fertilizer use, not correcting
inherent soil constraints or emerging nutrient deficiencies are the major contributors
of poor soil health. Continued high fertilizer usage in post-green revolution era has
also brought sustainability concerns. The hotspots of N fertilizer application have
shifted from the USA and Western Europe in the 1960s to eastern Asia in the early
twenty-first century. Europe, China, and India now account for over 50% of the N
used [26, 54]. Together with the enhanced cropping of nitrogen fixing legumes, it has
led to an expansion of the reactive N pool in the environment [28]. Inefficiencies in
N uptake lead to significant N losses and associated environmental problems which
are likely to be compounded by global climate change. Over 3/4ths of nitrous oxide
emissions from Indian agricultural soils are from applied nitrogen fertilizers [67].
Low fertilizer nutrients use efficiency by crops, typically for N (30–50%), P (15–
20%), S (8–12%), Zn (2–5%), Fe (1–2%) and Cu (1–2%) [61] has been attributed
to deterioration in soil health and poor synchronization between crop demand for
nutrients and their availability from soil.
Traditional farming is based on local practices and improving the fertilizer use efficiency will require transition to precision farming, which combines sensors, robots,
drones, GPS, mapping tools and data-analytics software to customize the care that
plants receive [49]. Data on individual plants like stem size, leaf shape and the moisture of the soil around a plant is fed to computers, which analyses for symptoms
of stress and gives feedback to farmers in real time to deliver water, pesticide or
fertilizer in required doses only. In map-based VRA technology a map is generated
of the farm and fed into the computer on board that decides which fertilizer should be
applied in a given parcel of land and in what quantity. Precision farming efficiently
manages spatial variations in the field, reduces water and chemical use, and produces
healthier crops and higher yields-all of which improves farmers’ incomes, conserves
resources and reduces chemical runoff. However, there are several challenges that
limit its broader adoption: socio-economical, agronomical and technological. Precision farming technology has moderate risk-reduction benefits which lead to higher
profits in the long run due to decreased variability in yields in a field. Precision
agriculture (PA) is now being increasingly adopted in developed countries [37];
according to Molin and Tavares [58] about 15% of the grain producers in Brazil,
use PA techniques to apply inputs at variable rates based on soil characteristics. In
many developing countries with small size land holdings, other site-specific nutrient
management techniques and drip irrigation/fertigation may be more simpler and
economic alternatives that approach precision agriculture in efficiency.
There has been a worldwide upsurge on interest in organic farming. As of 2015,
India had the most organic producers followed by Uganda and Mexico. In 2018, India
was 9th in terms of land under organic agriculture [102] with 3.56 million ha under