Agriculture Reference
In-Depth Information
Intensification of the rice-wheat production systems has spared agriculture
expansion in marginal areas and replacements in other cropping systems. Data in
Figure 5.1 show that achieving the present levels of wheat production in Indian
Punjab would have required an additional equal expanse of land acreage in Pakistan
Punjab. Prospects of bringing more area under cultivation and increasing irrigation
facilities are rather very limited, particularly in South Asia (Poster 1998; The 2030
Water Resources Group 2011), and therefore, crop intensification is inevitable.
Although crop intensification with associated production technologies signifi-
cantly increased food production, it had a lot of associated land degradation. The
problem of land degradation manifests itself in the Indo-Gangetic plains through
lower water use efficiency, lower factor productivity, reduced biodiversity, multinutri-
ent deficiencies, declining water tables, groundwater pollution, etc. (Abrol and Gupta
1998; Mehla et al. 2000; Gupta et al. 2003; Ladha et al. 2003; Pathak et al. 2003;
Chandna et al. 2010; Rodell et al. 2010). The report of the '2030 Water Resources
Group' has projected a deficit of 755 billion m
3
of water in India and an annual deple-
tion of 13-17 billion m
3
of water from the northwest plains in Punjab, Haryana, and
western Uttar Pradesh (Rodell et al. 2010). The food situation is further complicated
because climate changes have been projected to render almost 40% of the current
area under wheat, unsustainable in the future (Ortiz et al. 2008), and each degree
Celsius increase in temperature is expected to raise additional water needs by 2%
to maintain crop yields at current levels (Report of Subgroup III Soil Health and
Water Management. Planning Commission-ICAR-DARE, Govt. of India. 2011. New
Delhi) are some of the biggest threats to agriculture in the Indian subcontinent. The
current trends and future indication are, therefore, worrisome for rice-wheat systems
and require innovative interventions.
The demand and supply gap in irrigation water can be bridged by either increas-
ing its supply or improving its productivity (more crop per drop) by growing more
water-efficient crop (substitution/diversification), reduced runoff, increased rainwater
infiltration, and reduced evaporation. CA practices encompassing no-till or reduce
tillage, along with residue retention and appropriate crop rotation, can improve the
water productivity and sustain the cereal production systems at a higher level over
time. Keeping in view all these facts and issues, it was felt pertinent to analyze and
discuss the productivity gaps experienced in cereal crops of South Asia, and the abil-
ity of CA and plant breeding intervention to minimize these gaps.
5.2 AGRICULTURAL PRODUCTIVITY GAPS AND SCOPE
FOR IMPROVEMENTS THROUGH MANAGEMENT
The yield gap concept rests on the definition and measurement of the yield potential.
Practical yield gap (gap I) can be defined as the difference between the maximum
attainable yield (yield obtained in yield maximization trials with best management
practices) and the average yields attained at the farm level in the county/districts.
This yield gap is due to poor management of the crop at the farmers' level. The other
yield gap, designated as yield gap II, is between the theoretical potential yield (simu-
lated yields with no constraints of water and nutrient) and the maximum attainable
yield. This yield gap is usually caused by factors beyond management and hence
