Feeding 11 billion on 0.5 billion hectare of area under cereal crops

13 Pages·2016·1.05 MB·English

REVIEW
Feeding 11 billion on 0.5 billion hectare of area under cereal crops
Rattan Lal
Carbon Management and Sequestration Center, The Ohio State University, Columbus, Ohio 43210
Keywords Abstract
global cereal yield, global population, per
capita cropland area, soil health, Sustainable Despite impressive increase in global grain production since 1960s, there are
intensification. 795 million food- insecure and ~2 billion people prone to malnutrition. Further,
global population of 7.4 billion in 2016 is projected to increase to 9.7 billion
Correspondence by 2050, with almost all increase occurring in developing countries. Thus, it is
Rattan Lal, Carbon Management and recommended that global food production be increased by 60 to 70% between
Sequestration Center, The Ohio State
2005 and 2050. Global crop production increased threefold between 1965 and
University, Columbus, OH 43210.
2015 with a net increase of only 67 million ha (Mha) of cropland area. None-
Tel: [phone]; Fax: [phone];
theless, agronomic yield of food staples can still be tripled or quadrupled in
E-mail: [email protected]
Sub- Saharan Africa (SSA), South Asia (SA), and the Caribbean by a widespread
Funding Information adoption of site- specific best management practices of sustainable intensification
No funding information provided. (SI). Rather than expanding the area under cropland, agriculturally marginal
and degraded soils can be set aside for nature conservancy. The global average
Received: 24 August 2016; Revised: 18
cereal yield of 3.27 Mg ha−1 in 2005 can be increased to 5 Mg ha−1 by 2050,
November 2016; Accepted: 18 November
6 Mg ha−1 by 2080 and 7 Mg ha−1 by 2100 through SI of agroecosystems in
2016
SSA, SA and elsewhere. The strategy of “producing more from less” necessitates
Food and Energy Security 2016; 5(4): restoration of soil health and increasing soil organic carbon (SOC) concentra-
239–251 tion to be more than 1.5–2.0% in the rootzone. The goal of SOC sequestration
is in accord with the “4 per Thousand” initiative proposed at COP21 in 2015.
doi: 10.1002/fes3.99 Therefore, global food demands can be met despite the decreasing trends in
the per capita cropland area by 2050 – 0.17 ha in the world and 0.15 ha in
developing countries. While enhancing productivity by SI, the strategy is to
simultaneously reduce food waste, increase access and distribution of food, and
promote plant- based diet. The goal is to reconcile high production with better
environmental quality, develop urban agriculture (aquaponics, aeroponics, and
vertical farms), promote nutrition- sensitive farming, and restore degraded soils.
Sustainable intensification of agroecosystems can produce enough food grains
to feed one person for a year on 0.045 ha of arable land.
Introduction there remain some 795 million food-i nsecure people (FAO,
2015a; Fig. 1) and an additional ~2 billion are prone to
Achieving food security, eliminating hunger, and removing hidden hunger or malnutrition caused by the deficiency
poverty have been among important foci of the Agenda of micronutrients and protein (Ruel- Bergeron et al. 2015).
21 (UN, 1992), Millennium Development Goals (UN, The elusive problems of food and nutritional insecurity
2000), and the Sustainable Development Goals (UN are intricately interconnected with those of the degrada-
2015a,b). While there are strong criticisms of broad- brushed tion of soil and water resources. The extent and severity
initiatives (Horton 2014), these are generic guidelines at of degradation may be related to the increasing rate of
all levels of governance. Yet, the insidious problem of population, which have and continue to differ among
food and nutritional insecurity plagues humanity even different regions of the world (Fig. 2). The rate of popu-
more now than ever before. While the number of food- lation increase has and continue to be more in Asia,
insecure population has progressively decreased since 1990s, Africa, and Latin America (AAL) compared with that in
© 2016 The Authors. Food and Energy Security published by John Wiley & Sons Ltd. and the Association of Applied Biologists. 239
This is an open access article under the terms of the Creative Commons Attribution License, which permits use,
distribution and reproduction in any medium, provided the original work is properly cited.
Feeding 11 Billion R. Lal
(mechanisms), factors (environmental controls), and causes
(anthropogenic activities) which mutually reinforce and
aggravate the problems of soil/water degradation and per-
petuation of food insecurity and hidden hunger (Fig. 4).
As a medium for crop and pasture production, soil
management affects agronomic yield and nutritional qual-
ity. The goals of sustainable soil management are to maintain
and restore the stock of soil organic carbon (SOC) at
above the threshold/critical level of 1.5–2.0% in the root
zone (Loveland and Web 2003; Patrick et al. 2013), espe-
cially for efficient management of nitrogen (Patrick et al.
2013) and water resources. It is widely documented that
management of SOC is important to maintaining soil
productivity, and especially the yield stability (Overstreet
and DeJong-H uges 2009; Seremesic et al. 2011)).
Improving agronomic productivity and achieving yield
stability under changing and uncertain climate are impor-
tant to feeding the world population of 7.4 billion in 2016
and projected to be 9.7 billion by 2050 and 11.2 billion
by 2100 (UN 2015a,b; Table 1, Fig. 3). Therefore, the
Figure 1. Global extent of food-i nsecurity and undernourishment objective of this article is to document that rather than
(Redrawn from the data in FAO 2015b,c). bringing more land under agriculture, food demands can
be met with soil and water resources lesser than those
being used at present through judicious use and sustain-
North America, Europe, and Oceania (NEO). Almost all able intensification (SI) of agroecosystems, so that extra
of the future increase in world population will occur in land and water can be saved for nature conservancy?
the AAL region (Fig. 3), with a strong impact on soil,
water, and the environment. These naturally reinforcing
Prevalence of Food Insecurity
problems (population increase, food insecurity, and soil
degradation) are affected both by biophysical factors and Food insecurity remains an issue in Africa and Asia (Fig. 1),
the serious issues pertaining to the human dimensions and will continue to do so for decades to come. Yet, the
(e.g., social, economic, cultural, ethnical, and political). number of food- insecure population in the world has
Indeed, there exists a strong interaction among processes decreased from more >1 billion in 1990–92 to 795
Figure 2. Rate of increase of the world population for different regions (recalculated and redrawn from data in the U.N. 2015b).
240 © 2016 The Authors. Food and Energy Security published by John Wiley & Sons Ltd. and the Association of Applied Biologists.
R. Lal Feeding 11 Billion
Figure 3. Trajectory of the growth of human population from ~4 million in 10,000 BCE and 300 million at 1 AD, to 11.2 billion by 2100, with almost
all of future growth occurring in presently developing countries of Asia, Africa, Latin America, and the Caribbean (Plotted from the data by Fyfe 1997;
Haub 2011; U.N. 2015a,b; Geohive 2016 and other sources). AAL = Africa, Asia, and Latin America; NEO = North America, Europe, and Oceania.
million in 2014–16 (Fig. 1). In this context, a consider- production must also come from existing land resources
able progress has also been made in developing countries through the adoption of BMPs for site- specific situations.
of Asia and Africa. The absolute number of food- insecure The trend of decreasing total agricultural land area must
population in developing countries was 810 million (19.7%) continue throughout the 21st century, so that agricultur-
in 1990–92, 827 million (15.9%) in 2005–07, 687 million ally marginal and degraded lands can be set aside for
(11.7%) in 2015, and is projected to be 543 million (7.9%) nature conservancy, and SOC sequestration.
in 2030 and 318 million (4.1%) in 2050 (Alexandratos
and Bruinsma 2012). A high rate of population growth
Land and Water Resources for
in developing countries, where almost all the future popu-
Agroecosystems
lation growth will occur (Figs. 2, 3), along with slow
adoption of the proven best management practices (BMPs) Land area (million hectare, Mha) allocated for cropland
are among the reasons of persistence of hunger through and grazing land in 2000 was 1381 and 3357, respectively
2050 and beyond. Thus, it has been suggested that feed- (FAO, 2015b,c). Of this, land area equipped for irrigation
ing a population of 9.7 billion by 2050 will require overall was 280 Mha. For a population of 6896 million in 2000,
increase in food production by 60–70% between 2005–07 the per capita allocation of land resources in 2000 was
and 2050 (Bruinsma 2009; FAO, 2015c). If this assump- 0.20 ha for cropland, 0.49 for grazing and pasture land,
tion is correct, it would require additional cereal produc- and 0.04 ha for irrigated land. In 2013, when the world
tion of 1 billion Mg, and meat production by over 200 population reached 7162 million, land resources (Mha)
million Mg to a total of about 500 million Mg by 2050 allocated were 1408 for cropland, 3354 for grazing land
(FAO 2015c). Rather than producing more food, better and pastures, and 325 equipped for irrigation. Thus, the
utilization of the food produced and efficient use of soil per capita land resources in 2013 were 0.197 ha of crop-
and water resources would be a better option. land, 0.47 ha of grazing land and pastures, and 0.045 ha
Global crop production has increased threefold over of land equipped for irrigation. However, the per capita
the 50-y ear period from 1965 to 2015, primarily through arable land area will decline by 2050–0.18 ha in the world
increase in yield per unit area. Increase in global cropland compared with 0.15 ha in developing and 0.42 ha in
area during this period was only 67 Mha, with increase developed countries (Fig. 5). In many densely populated
of 107 Mha in developing countries and decrease of 40 Mha countries (e.g., Bangladesh), the per capita arable land
in developed countries. Similarly, future increase in area is already <0.04 ha. With adoption of BMPs, and
© 2016 The Authors. Food and Energy Security published by John Wiley & Sons Ltd. and the Association of Applied Biologists. 241
Feeding 11 Billion R. Lal
Figure 4. Common determinants of soil degradation and food/nutritional insecurity.
2050. The strategy is to manage the soil and water resources
Table 1. Food demand during the 21st century (Data on population, per
capita food consumption, and cereal production are from FAO 2009; according to the site-s pecific BMPs (conservation agricul-
Alexandratos and Bruinsma 2012; U.N. 2015a,b) ture, precision farming, drip sub-i rrigation, integrated
nutrient management, and improved varieties) so that
Parameter Year
agronomic yield can be increased through enhancement
2005–07 2050 2080 2100 of the use efficiency of inputs and decreasing losses by
erosion, leaching, and volatilization.
Population 6.4 9.7 10.6 11.2
Yet, the finite soil resources must be protected for
Per capita food consumption 2772 3070 3200 3300
other ecosystem services. The land area allocated to
(kcal)
Cereal production (106 Mg) 2012 3012 3350 3540 agriculture in 2013 included 1408 Mha for cropland for
Land area needed for 613 600 560 500 a total cereal production of 2.82 billion Mg, 3354 Mha
intensive agriculture (Mha) for grazing land for a total meat production of 290
The desired global average 3280 5000 6000 7000 million Mg, and 325 Mha of land area equipped for
cereal yield (kg ha−1) irrigation (FAOSTAT, 2016). The fertilizer use (106 Mg
of nutrients per year) in 2012, 2020, and 2050 is pro-
judicious use of soil and water resources, these land jected to be 123, 135, and 236 for N, and 46.0, 47.6
resources are more than sufficient to meet the expected and 83.7 for P (IFDC, 2004; FAOSTAT, 2016). Global
food needs of the world population of 9.7 billion by pesticide use was estimated at 2 million Mg in 2014,
242 © 2016 The Authors. Food and Energy Security published by John Wiley & Sons Ltd. and the Association of Applied Biologists.
R. Lal Feeding 11 Billion
Figure 5. Estimates of temporal changes in per capita arable land area in the world, developing, and developed countries between 1961 and 2050
(Redrawn from Bruinsma 2009).
of which 25% was used in the U.S., 45% in Europe, With the business-as-usual (BAU), there are several esti-
and 30% in other countries of the world (De et al. mates of the required cereal yield and total production
2014). Further, the use of fertilizers, pesticides, and (Table 1). Wild (2003) estimated that the global average
chemicals, along with the irrigation water must be reduced cereal yield of 3.27 Mg ha−1 and total production of 2.24
to the minimum required. billion Mg would have to be increased to 3.60 Mg ha−1
and 2.78 billion Mg in 2025, and 4.3 Mg ha−1 and 3.3
billion Mg by 2050. However, with the growing preference
Global Food Demand
for animal-b ased diet, global average cereal yield and total
Cereals presently account for only 37% of total caloric cereal production would have to be 4.4 Mg ha−1 and 3.63
intake in developed countries compared with 71% in least billion Mg by 2025, and 6.0 Mg ha−1 and 4.6 billion Mg
developed, and 54% in other countries (OECD-F AO, 2015). by 2050, respectively (Wild 2003). Yet, a widespread adop-
Thus, rising income and growing affluence is changing food tion of proven BMPs can and must increase the global
habits in preference of animal-b ased diet. Per capita caloric average cereal yield to 5, 6, 7 Mg ha−1 by 2050, 2080, and
intake is projected to increase between 2002–04 and 2012–14 2100, respectively. This is an achievable goal with already
from 1750 to 2150 kcal per day per person in least devel- available and proven technology. That being the case, it
oped countries, 2400–2800 in other developing countries, is possible to decrease the cropland area to as low as
to 2750–2900 in developed countries. However, the pro- 500 Mha by 2100 (Table 1).
portional caloric intake from meat-b ased diet will increase While enhancing agronomic yields through adoption of
more rapidly in developing than in developed countries BMPs and sustainable intensification, there are other con-
(OECD-F AO, 2015). Thus, global meat consumption is straints on available land resources which must also be
expected to grow by an annual average of 1.4%, with addressed. Soil degradation remains to be a major issue,
additional consumption of 51 million Mg of meat by 2024 with accelerated soil erosion affecting 1.1 billion hectare
(OECD-F AO, 2015). The overall demand for agricultural (Bha) by water and 0.55 Bha by wind erosion (Oldeman
products is projected to grow at 1.1% per year from 2005–07 1994). Secondary salinization, a serious problem in arid
to 2050 due to population growth, increase in per capita and semiarid regions, affects 20% of the irrigated land
consumption, and changes in diet preferences toward animal- area. Nonpoint source pollution and eutrophication of
based food (Alexandratos and Bruinsma 2012). Regions surface waters are causing algal blooms in the Great Lakes,
with increase in food demands, especially the animal-b ased Golf of Mexico, Chesapeake Bay, Lake Taihu in China,
food, include sub-S aharan Africa (SSA) and South Asia Baltic Sea, and other regions receiving intensive use of
(SA). This is an important issue that must be addressed chemical fertilizers. Intensive irrigation is leading to rapid
through education at all levels. water depletion in many regions (Gleesen et al. 2012),
© 2016 The Authors. Food and Energy Security published by John Wiley & Sons Ltd. and the Association of Applied Biologists. 243
Feeding 11 Billion R. Lal
including Ogallala (Alley et al. 1999; Amelinckx 2015), 6. Raising agronomic productivity from existing lands, restor-
North China Plains (Yang et al. 2015), and the Indo- ing degraded lands, sequestering SOC and enhancing
Gangetic Plains (Kerr 2009). Conversion of prime agri- biological nitrogen fixation, and setting aside some of
cultural land to urban expansion and surface sealing by the existing agricultural land for nature conservancy.
cement and asphalt to develop infrastructure are reducing
land area available for agriculture. By 2030, global urban
Sustainable Intensification for Saving
land cover will increase by 152 Mha, more than 10% of
Land and Water Resources
the present cropland area of the world. These degraded
lands must be restored, and used for implementation of The strategy of SI implies producing “more from less,”
the “4 per Thousand” program (UNFCCC, 2015). of less land area, less water used for irrigation and pro-
cessing, less fertilizers and chemicals applied, less energy
consumed in farm operations and processing/transport
Strategies for Feeding the World
etc., and less gaseous emissions (CO, CH, NO) in
2 4 2
farm- related activities, food processing, and waste disposal.
Resources (land, water, chemicals, energy) already used
In the context of soil and water management, it is essen-
for agriculture must be reduced by enhancing the use
tial to replace all the nutrients harvested in agricultural
efficiency and decreasing losses. For example, 38% of Earth’s
produce, respond rationally (based on scientific concepts)
terrestrial surface is used for agriculture (cropland, grazing
to anthropogenic perturbations (e.g., land use and land
land, agroforestry etc.), and 70% of agricultural land
use change), and predict environmental impact of human-
(3354 Mha out of 4762 Mha) is allocated to raising ani-
ity (I = PAT, P is population, A is affluence and T is
mals for production of 290 million Mg of meat and dairy
technology) (Holdren and Eicher 1974), and reduce it.
products. Further, 70% of the global freshwater withdrawals
The importance of enhancing soil health through man-
are used for irrigation of 325 Mha. In the context of
agement of SOC cannot be overemphasized (Lal 2016;
anthropogenic emissions, 30–35% of global greenhouse gas
Fig. 6). The average increase in grain yield by increase
(GHG) emissions are directly and indirectly contributed
in SOC pool in the rootzone (0–20 cm) by 1 MgC ha−1
by agriculture and food-r elated processes (IPCC, 2014).
may be as much as (kg ha−1) 100–300 for corn, 20–50
Despite the disproportional utilization of all these resources,
for soybean 20–70 for wheat, 30–60 for beans, 10–50 for
with severe ecological and environmental footprint, 1 in
rice, 80–140 for sorghum, and 30–70 for millet (Lal 2006,
9 persons (795 out of 7400 million) is prone to hunger,
2010a). Residue retention is essential to maintaining SOC
and 1 in 5 to malnutrition. Apparently, the BAU is not
(Karlen et al. 2009), and the latter to improving soil
an option, and must be objectively and critically assessed.
health and human nutrition (Lal 2009). Judicious man-
It is widely believed that 2.8 billion Mg of cereals
agement of the coupled cycling of HO, C, N, P, and S
produced annually are adequate to feed 7.4 billion people, 2
(Lal 2010b) is critical to improving biogeochemical cycling
with per capita consumption of 378 kg per person per
of elements and enhancing the use efficiency of inputs
year. Indeed, the total amount of food produced (grains,
(Lal 2010a,b,c). The strategy is to adopt site-s pecific BMPs
meat, fish, poultry, fruits, vegetables, etc.) may be adequate
which create a positive soil C budget. The latter involves
to feed even a world population of 10 billion because
land application of biomass-C (C = biomass input by
almost 1 billion Mg of grains produced are wasted enroute i
crop residues, deposition and use of inputs such as manure,
from field to the fork (Lipinski et al. 2013; Nunley 2013).
composting, cover cropping, biochar, etc.) to exceed its
Therefore, a prudent strategy to advance food and nutri-
losses (C = erosion, decomposition, leaching). Thus, the
tional security must consider the followings: l
removal of crop residues for cellulosic ethanol (Malcolm
1. Reducing the food waste equivalent to 30% of total and Aillery 2009) and other competing uses must be done
production; prudently and rationally because there may be no such
2. Increasing access to food by addressing poverty, civil thing as free biofuels from crop residues (Lal and Pimentel
strife, inequity, wars, political instability, and political/ 2007). Biomass from other sources such as switchgrass
ecological refugees; (Schmer et al. 2007), miscanthus, and other C-4 grasses
3. Improving food distribution by strengthening infrastruc- (van der Weijde et al. 2013) may be better alternatives
ture at global, regional, and local scale; than that of harvesting crop residues from arable lands.
4. Enhancing use of pulses and plant-based diets and iden-
tifying alternative sources of proteins;
Future Strategies
5. Accepting personal responsibilities of not taking food
and natural resources (soil, water, vegetation) for granted; Agriculture, as we know it, is on a crossroads. Low grain
and yields obtained under extractive farming practiced widely in
244 © 2016 The Authors. Food and Energy Security published by John Wiley & Sons Ltd. and the Association of Applied Biologists.
R. Lal Feeding 11 Billion
Figure 6. Impacts of soil organic carbon pool on improvements of soil physical, chemical, biological, and ecological properties.
SSA and SA, producing ~1 Mg ha−1 of cereals and 300– and SIC to 3-m depth including SOC pool in the Cryosols)
400 kg ha−1 of grain legumes, must be replaced by science- (Batjes 2014; Le Quéré et al. 2015). Being a smaller pool
based practices of SI for producing 3–5 times the present compared with that of the terrestrial pool (pedologic plus
crop yields. Yet, the ecological footprint of SI must be reduced. biotic), the atmospheric pool is easily overwhelmed by anthro-
Any strategies of achieving high production must be reconciled pogenic perturbations. Thus, sustainable management of world
with low environmental footprint. Indeed, the so-c alled soils (Lal 2004a,b) and biotic resources (Lal 2010c) is critical
C-c ivilization (Lal 2007) is also challenged by the issue of to mitigating the climate change through implementation
“peak soil” and “endangered or extinct soils” (Pimentel and of the initiative such as the “4 per Thousand” (UNFCCC,
Sparks 2000; Ditzler 2003; Tennesen 2015). In addition to 2015; Chambers et al. 2016).
its role as a medium for crop growth under traditional agri-
culture, soil is a source of numerous other ecosystem services
Urban agriculture (UA)
including the source of antibiotics (Christina et al. 2013; Ling
et al. 2015; Khapton 2016) and other pharmaceuticals. Global urban population is increasing rapidly, and about
70% of the 9.7 billion (6.8 billion) will live in urban
centers by 2050 (U.N. 2015a,b). Land area under urban
Managing the carbon cycle
centers in the U.S. may be as much as 7–16 M ha by
The severe disturbance of the global C cycle by anthropogenic 2050 (USDA, 2016). Populations of mega cities has, and
activities is the root cause of numerous ecological issues of will continue to grow. For example, the expected increase
the 21st century, including the climate change (Fig. 4). The in population (million) from 1950 to 2050 is 7.9 to 22.8
atmospheric C pool is approaching 840 Pg, in 2016, in by a factor of 2.9 for New York, 2.9 to 14.3 by a factor
comparison with 6000 Pg of the total pedological pool (SOC of 5 for Rio de Janeiro compared with 0.1 to 14.3 by a
© 2016 The Authors. Food and Energy Security published by John Wiley & Sons Ltd. and the Association of Applied Biologists. 245
Feeding 11 Billion R. Lal
factor of 158 for Nairobi, Kenya (Table 2). These megaci- of producing food and other victuals for the expected
ties require a lot of food and other essentials for their population of 9.7 billion by 2050 and 11.2 billion by
sustenance. For example, it takes 30,000 ha of land to 2100. The question is not whether the technology exists
provide accommodation and infrastructure to 1 million to produce enough food, but how to produce it without
people. The annual global increase of 75 million people jeopardizing the environment? Indeed, the process thus
would divert about 2.25 Mha of land mostly out of agri- far in enhancing agronomic yield in the U.S. from about
cultural land use. Megacities with population of 10 million 0.8 Mg ha−1 in 1750 to >10 Mg ha−1 at present is phe-
or more are 28 in 2015 and will be 41 in 2030 (U.N. nomenal. On a global scale, advances in agriculture have
2015a,b). A city of 10 million requires 6000 Mg of food led to increase in world population (billion) from about
per day. Thus, a vast amount of plant nutrients (N, P, 0.8 in 1750 to 7.4 in 2016 (Fig. 7).
S etc.) are brought into the city and are not returned to Progressive innovations in agricultural technology
the land. Therefore, urban agriculture (UA) must be include those based on: hand tools (1750–1850); draught
developed to meet 20–25% of the food demands (e.g., animals and crop rotations (1850–1950); the Green
fresh produce, vegetables, aquaculture) through production Revolution technologies of input (fertilizer, irrigation) –
from within the urban and peri-u rban areas. The strategy responsive varieties (1975–2000); conservation agriculture,
is to recycle nutrients and water, which are now a liability precision farming, perennial culture (Glover et al. 2010;
and cause of environmental pollution, through the strate- Kane et al. 2016), genetically modified crops, and soil C
gies of soil- water- waste nexus (Lal 2016). Vertical farms, sequestration (2000–2025) (Lal, 2004a, b). Innovative agri-
using aeroponics and aquaponics technology (without soil), cultural options for the immediate future (2015–2025)
are being developed to grow greens in mega cities. One include SI, improving rhizospheric processes to enhance
such vertical farm is being developed in Newark, New use efficiency of inputs and strengthen disease-s uppressive
Jersey (Despomier 2011; AeroFarms, 2016). attributes of the rootzone, develop soil-l ess culture (aqua-
In addition to vertical farm and other innovative ideas, ponics, aeroponics, hydroponics), adopt the nexus approach
UA also involves conventional system comprising of cul- (Lal 2016), enhance phytobiome management (Beattie et al.
tivating, processing, and distributing food around and 2015), explore options of alternative sources of protein
within an urban community including vegetables, livestock (e.g., algae, sea/duckweed, insects), develop agricultural
produce, agroforestry, aquaculture etc. It also includes robots (Astrand and Baerveldt 2002; Bangert et al. 2013),
backyard, rooftop and balcony gardening, community and strengthen smartphone extension/communication sys-
gardening in vacant lots and parks and on restored land tems (Xue et al. 2010; Lantzos et al. 2013). Algae is a
from abandoned homesteads and parking lots. Among crop of the future, and microalgae is a potential source
U.S. cities with well-e stablished UA are Austin (TX), Boston of proteins (Becker 2007). Microbial protein is another
(MA), Chicago (IL), Cleveland (OH), Minneapolis (MN), option for human and animal feed (Kuhad et al. 1994).
New York (NY), Portland (OR), San Francisco (CA), and Between 2025–2050, soil scientists must reach out and
Seattle (WA). UA must be expanded in all large, medium, open new frontiers such as precision agriculture in a
and small urban communities. broader context, synthetic soils, soil-l ess farming, vertical
farms, soil microbiomes, and space farming to understand
pedological processes in a gravity- less environment (Fig. 7).
Innovation in agriculture
Agriculture and food production have been a success story
of the 21st century, especially since 1960s, and is capable Saving soil
The overall strategy is to save the soil for ecosystem
Table 2. Temporal change in urban population of some mega cities services other than agriculture and food production,
(Adapted from UN, 2015b) produce more from less, and convert some of the extra
land back to nature for sequestering C, strengthening
City 1950 1980 2015 2025 2050 Factor
biodiversity, improving water quality, and promoting
New York 7.9 7.1 8.5 20.6 22.8 2.9 nature conservation. The projected climate change will
Rio de Janeiro 2.9 8.7 11.9 13.4 14.3 5 affect changes in soil- forming factors in terms of the
Los Angeles 2 3 18.7 13.7 16.4 8.3 input of biomass- C into soil, soil moisture and tem-
Mexico City 3.1 8.8 21.2 21 24.3 8
perature regimes, hydrological processes (water retention
Mumbai 2.9 8.1 26.1 26.4 42.4 14.6
and movement) and change in components of the hydro-
Delhi 1.4 5.6 16.8 22 35.2 25.3
logical cycle (rainfall, runoff, evapotranspiration) and
Lagos 0.3 4.4 23.2 24.2 32.6 112.5
Nairobi 0.1 0.9 3.8 5.9 14.3 158.3 erosivity of rainfall (intense rains with a high kinetic
246 © 2016 The Authors. Food and Energy Security published by John Wiley & Sons Ltd. and the Association of Applied Biologists.
R. Lal Feeding 11 Billion
Figure 7. Technological evolutions in agriculture from 1750 to 2050. Revised and updated from Lal (2000).
energy and momentum). Thus, climate change would of soil systems under low gravity environments of Moon
bring about changes in soil properties and processes (0.16 g), Mars (0.38 g), and the international space sta-
(Buol et al. 1990; Goryachkin and Targulian 1990; tion (0 g) are not understood (Maggi and Pallud 2010).
Scharpenseel et al. 1990; Sombroek 1990; Brinkman and In conjunction with the study of soil processes, those of
Sombroek 1996). Because of the shifts in biomes, agri- plant growth and morphogenesis must also be assessed
cultural activities will expand into the present boreal under different gravity conditions (Hoson 2014; Kiss 2014).
regions. Thus, understanding soil processes in cold envi-
ronments (Olivia et al. 2014) under warmer climates
(Brevik 2012) are important considerations. The tem-
Soil Organic Carbon as an Indicator of
perature dependence of SOC decomposition (Kirschbaum
Soil Health and Environment Quality
1995), feedback to climate change (Kirschbaum 2000;
Davidson and Janssens 2006), and effects on microbial There exists a strong need to enhance soil structure/soil
processes (Classen et al. 2015) are priority researchable health (Pagliai et al. 2002; Rojas et al. 2016) and restore
issues. In the context of food security, it is pertinent environment quality for mitigating climate change and
to understand the site- specific impacts of climate change reducing risks of eutrophication. The strategy is to feed
on soil properties and processes (Brevik 2013) in rela- the soil to feed the plant, while restoring soil health and
tion to agronomic production. Relation between climate environment quality. The magnitude, quality, and dynam-
variation and trends in crop yield (Vermeulen et al. ics of SOC are important indicators of soil health and
2012; Ray et al. 2015) will need to be established under environment quality (Ogle and Paustian 2005). Among
a range of biophysical environments. specific attributes of SOC, microbial biomass C (MBC)
is a pertinent indicator of changes in soil health and the
attendant impact on environment quality (Hargreaves et al.
Space farming
2003). Changes in particulate organic C (POC) are also
Attempts toward human colonization of space (Moon and sensitive to land use and land use change (Cambardella
Mars) will be made between 2020 and 2050. Therefore, and Elliot 1991). Thus, SOC sequestration in agricultural
it would be pertinent to study space agriculture under soils is an important strategy to mitigate climate change
micro- and hypo- gravity conditions. There is an increasing (UNFCCC, 2015) and advance food security (Lal 2004a,
interest in soil- based agriculture involving bioregeneration 2010b). There are numerous technological options of
support systems to produce food and generate oxygen withdrawing CO from the atmosphere and storing it in
2
(O). Yet, hydrodynamics and biogeochemical functioning the soil (Kane 2015). The potential of C sequestration in
2
© 2016 The Authors. Food and Energy Security published by John Wiley & Sons Ltd. and the Association of Applied Biologists. 247
Feeding 11 Billion R. Lal
the terrestrial biosphere (soil and vegetation) is about achieving food security especially with regard to reducing
3.0 PgC yr−1 (Pacala and Socolow 2004; Le Quéré et al. waste, increasing food access, identifying new sources of
2015) to 3.8 PgC yr−1 (Lal 2010b). However, there are protein (e.g., algae) and creating peace and political
challenges to adapt technologies under site- specific condi- stability.
tions, such as conservation agriculture (Powlson et al. Although sustainable management of soil is crucial to
2014), and issues of C saturation (Six et al. 2002). mitigating climate change and advancing food security,
stewardship of earthly resources and understanding of the
biogeochemical and hydrological processes of soils of
Conclusion
celestial bodies (Moon, Mars) will emerge important themes
The food demands of the growing world population, 7.4 of future research. Soil science must evolve to meet chal-
billion in 2016 and projected to be 9.7 billion by 2050 lenges of the 21st century.
and 11.2 billion by 2100, can be met by reducing the
allocated land area for cereals and water resources for
Conflict of Interest
irrigation through adoption of site- specific practices of
sustainable intensification and restoration of soil health. The author is the director of the Carbon Management
Sustainable intensification of agroecosystems can produce and Sequestration Center of the Ohio State University,
enough grains on 0.045 ha to feed one person for one Columbus, OH.
year. Crop yields in Sub- Saharan Africa, South Asia, and
elsewhere in the developing countries (e.g., the Caribbean) References
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