Annex 3. to Identify the Means by Which Global Food Production Has Increased Since 1966

ANNEX 3. TO IDENTIFY THE MEANS BY WHICH GLOBAL FOOD PRODUCTION HAS INCREASED SINCE 1966.

In this report we quantify the increase in food production over the last 40 years and describe how these increases have arisen. We also summarise agricultural policies during that period and their impacts on food production both directly in the regions where the policies were applied and also on other regions.

Over the last c. 40 years the Earth's population increased from c. 3.5 • 109 to c. 6 • 109 with forecasts of further increases to between 8 and 9 • 109 by 2030. Since c. 1966 global food production has increased by c. 170%, broadly in line with the increased demand for food. Greater yields per area of land through increased inputs has been by far the largest source of increase in world crop production, accounting for approximately 78% of the increase form 1961 to 1999. A further 15% of the increase came from the expansion of arable area. The other 7% of the increase in crop production in the world came from increased cropping intensity (growing more crops per year or over a crop rotation).

1.Introduction

This part of the report provides an assessment of the extent to which food production increased between c. 1966 and 2000. We also report the extent to which these increases were due to greater productivity: greater yields per hectare (ha); greater intensity of cropping, or to increases in the area of land used for agricultural production. In addition we report assessments of the extent to which greater yields per ha were due to increased inputs of agrochemicals and to breeding of more productive crop varieties.

The factors affecting food production, and how, and to what extent, it increases are many and varied. The main purpose for expanding food production is to feed a growing population; however, a number of factors determine what sorts of food are eaten as populations increase. For instance, we have seen in recent years an increase in meat consumption, and a corresponding increase in grains used for livestock feed, not due to population increases but due to increasing wealth, driven by a range of means and changing social aspirations.

These kind of issues – population growth, diet trends, wealth and aspirational change, for example – are all important in determining demand for food, and hence production, but they were not investigated here. Instead, the purpose of this Task was to consider the physical factors which have allowed production to increase to meet changing demand.

Broadly speaking, based on a literature review, the means of increased food production can be listed as follows:

(i) Increased crop yields from the land already used by agriculture (increased productivity) through:

• Increased nutrient and agrochemical inputs
• Increased nutrient-use efficiency
• Increased water-use and irrigation efficiency

• Increased cropping intensity (growing more crops per season, reducing the proportion of fallow in the rotation)
• Improved crop cultivars (which may be a means of achieving the means above)

(ii) Increased crop production through:

• Increasing the land area used for agriculture

(iii) Special consideration was also given to:

• Livestock production increase
• Increased aquaculture

In this report 'production' is defined as the total amount of food produced per year, while 'productivity' is defined as food produced per ha per year.

2.Production trends c. 1966 to c. 2000

The studies we have evaluated in preparing this report have not always covered the same time periods. We therefore took an approximate date of assessments of historic trends to finish around the year 2000.

Between 1969 and 1999, global crop production increased by 126%; in developing countries over this period the increase was 191%. Between the early 1960s and the mid 1990s, average global cereal yields increased from 1.23 t/ha to 2.55 t/ha. Total cereal production grew from 420 to 1,176 million tonnes per year (UNCTAD-UNEP, 2008). In some countries, such as England, yield increases have been significantly greater. For instance, according to Pretty et al. (2000) 'compared with 1950, per hectare yields of wheat, barley, potatoes and sugar beet have tripled, while milk yields per cow have more than doubled'.

Looking specifically at wheat, yields have fluctuated, generally on an upward trend, to different extents in different countries over the past 40 years. In Australia, for example, between 1961 and 2000 yields increased from 1.1 t/ha to 1.8 t/ha, and during the same period, yields increased in the US from 1.6 t/ha to 2.8 t/ha. In contrast, bigger increases in yield growth were seen in France where 2.4 t/ha increased to 7.1 t/ha and Canada where 0.75 t/ha increased to 2.4 t/ha (FAOSTAT, 2009). Yield of maize, another globally significant cereal, have also increased: in the Netherlands yields in 1961 were 3.9 t/ha and by 2000 this had risen to 11 t/ha. In the United States during the same period yields rose from 3.9 t/ha to 8.6 t/ha (FAOSTAT, 2009).

There are three ways in which crop production can be increased: increasing the land under cultivation; increasing cropping intensity and increasing inputs. The means by which cropping intensity and yields may increase can include factors such as new crops and breeds of livestock, improved rotations and technological advances in nutrition and pest control, and climate change which can prolong growing periods, and extend the range of some high-yielding crops.

Livestock yields have also increased since the 1960s. Globally, carcase weights of cattle increased from an average 174 kg in 1967/69 to 198 kg thirty years later, an increase of 14%. For developed countries this figure increased from 212 kg to 284 kg (34%) during the same period but the increase was just 9% (150-163 kg) in developing countries. These productivity increases have been accompanied by global increases in livestock numbers in all major sectors. The most significant increase has been in global poultry numbers which increased from around 5 billion in the late 1960s to nearly 15 billion at the end of last century. Likewise, egg and milk production have increased in developed countries during the same period (FAO, 2003).

Increases in ruminant and milk production during the past thirty years have been achieved by increasing production in mixed and intensive production systems much more so than in pastoral systems. Globally, ruminant production increased by 40% between 1970 and 1995 yet the global area of grassland increased by only 4% (Bouwman et al., 2006).

Increasing livestock productivity can be achieved by better feeding leading to animals fattening sooner and hence more and faster production cycles; alternatively, a combination of improved breeding, using techniques such as genetic selection and artificial insemination, and better feed, has lead to animals achieving greater finishing weights, or producing more milk and eggs, through increased feed utilisation efficiency. Improvements in veterinary medicines and more efficient management practices have helped in these processes.

Gains in the efficiency of UK dairy cows mean that the UK milk supply is today at the same level as it was in the 1970s, but with 40% fewer cows. The increases in yield are largely due to genetic improvement and better nutrition, meaning that modern production systems allow more of the feed intake to go towards production rather than maintenance of the animal (NFU, 2008 and Bouwman et al., 2006).

2.1Increased agricultural production from increasing crop yield

This section begins with a review of the increase in crop yield as this factor has played a prominent role in increasing food production in the world. The crop yield data in this study indicates ‘harvested yield’, i.e., actual quantity of produce obtained after harvesting (see Annex 1 for FAO definitions).

Yield growth can be attained through many means as shown in the subcategories listed in section 2:

• Increased nutrient and agrochemical inputs.
• Increased nutrient-use efficiency.
• Increased water-use and irrigation productivity.
• Plant breeding, which may also be a means of achieving the outcomes above.

Fertilizer is used to ensure an adequate supply of nutrients to crops contributing to increase in yield. In this Task, the use of fertilizer has been reviewed mainly on the basis of data on the supply of macronutrients per unit of cropped land: nitrogen (N); phosphorus (P); potash (K2O) which are essential for plant growth.

Increased nutrient-use efficiency (NUE) is most commonly defined as the crop output per unit of nutrient input. This can be expressed in many ways, such as partial factor productivity, agronomic efficiency, crop recovery efficiency, crop removal efficiency etc. Definitions of nutrient efficiency, calculations, and formulae are given in Snyder et al. (2005). For the purpose of this study, NUE means agronomic efficiency, which is crop yield increase per unit nutrient applied. By using fertilizers in the most efficient manner, nutrient loss is reduced and pollution, which can lead to environmental degradation, is minimised.

Since the early 1960s, yield growth through increased inputs has been by far the largest source of increase in world crop production, accounting for approximately 78% of the increase in world and 70% of the increase in developing countries (1961 –1999). A further 15% of the increase came from the expansion of arable area in the world (UNEP 2008:20); while for developing countries it was 22%. Moreover, 7% of the increase in crop production in the world came from increased cropping intensity; the figure was 5% for the developing countries. Figure 1 from FAO (2003) shows the contribution of these different means towards the increase in global and developing country food production.

However, this is not a homogeneous scenario that prevails in the developing world. The above mentioned means of increased global food production have had different impacts on increased food production in countries in Asia and Africa, depending on the type of farming systems, farming cultures and the economic conditions of the farming communities. Table 1 shows the regional differences in regard to the role of increased yield through enhanced inputs, nutrient-use efficiency and efficient water use:

Figure 1. Source: FAO (2003:39)

Table 1. Contribution of yield through increased inputs, nutrient efficiency and water use for growth in food production

1Source: FAO (2003) *no breakdown was given between improved NUE and increased inputs in the assessment of the contribution of increased productivity to increased production, 2Source; IPNI (undated), 3FAO (2005b), 4FAO(2002), 5FAO (2005c).

2.1.1 Increase in crop yield through use of inputs

It is apparent from Table 1 that use of fertilizer is the main input in Asia. Around half of the increase in crop production in South Asia is considered to be due to fertilizer use, which is much greater than the world average of 35%. Table 2, below, shows the increase in fertilizer consumption in India, the main agricultural producer in South Asia.

Table 2. Trends in the intensity of fertilizer consumption in India (kg/ha) (1959-2006)

Source: International Plant Nutrition Institute (IPNI) database

In China, average use of fertilizer is 194 kg/ha and in some areas of China the use of nitrogen-based fertilizers may be as much as 500-800 kg/ha. However, it must be noted here that China’s crop yield growth is now stagnating and such intense use of N-fertilizers is neither contributing to yield growth nor is it likely to be beneficial for the soil or the environment in general. Unlike Asia, sub-Saharan Africa shows a deficit in the use of fertilizers with only 35% of crop growth achieved through the use of fertilizers, which equates to average consumption of only 5 kg/ha. There is therefore potential for yield growth in Africa through increases in fertilizer use.

2.1.2Increase in crop yield through input-use efficiency

The concept of efficient nutrient-use in this study is essentially an offspring of the concept of balanced fertilizer use along with sound management practices and decisions. In developing countries the ratio between the use of N, P and K fertilizers is managed to get the best yields. The concept of nutrient-use efficiency recognises the fact that every nutrient in some way impacts on and is impacted upon by every other nutrient. Therefore, what needs to be ensured is that a given crop or a cropping system receives nutrients in optimum and adequate quantities at appropriate times through the most suitable method of application to reap a harvest which is remunerative and profitable to the farmer. In such situations, the amount and ratios of nutrients should be based on the native nutrient content of the soil, crop requirement and yield target, without any biased emphasis on any particular nutrient. This will ensure, along with sound management practices and decisions, increased efficiency of nutrient use in high production systems. Thus, site-specific nutrient management systems were proposed by Dobermann et al. (2002) in their extensive study on 179 sites in Asia. There are other organisations which have also conducted research on nutrient use efficiency. Figure 2 shows that N, P, and K use efficiency of hybrid rice declined with a gradual decrease in applications of associated nutrients recommended through regional soil tests.

Figure 2 (Source: IPNI database)

Figure 2 index: T1: Soil-test and Yield target based recommendation; T2, T3, T4 and T5 for N are 50%P, 50%K, 0%P and 0%K, respectively; T2, T3, T4 and T5 for P are 75%K, 50%K, 25%K and 0%K, respectively; T2, T3, T4 and T5 for K are 75%P, 50%P, 25%P and 0%P, respectively; T6, T7 and T8 refer to (-) Ca, (-) Zn and (-) B, respectively, for all three cases.

Figure 2 shows that in India the nutrient-use efficiency is greatest in regions where the N:P:K ratio are based on local soil testing and targets (T1).

However, the concept of balanced fertilization is not an exclusive NPK ratio strategy. With the adoption of exhaustive cropping systems, widespread deficiencies of sulphur (S) and the micronutrient zinc (Zn) and sporadic deficiencies of the micronutrients iron (Fe), manganese (Mn), and boron (B) have been noticed in intensively cultivated areas. Inclusion of these nutrients in fertilization programmes also show good results in yield growth in many studies in Asia. There is no blanket formula for nutrient-use management and a number of regional studies and recommendations are carried out by many organisations in the field. Such studies on South Asia, East Asia and South East Asia are found in the International Plant Nutrition Institute site (IPNI). The main observation from these studies is that NPK ratios vary widely based on regional targets and characteristics. Also in most Asian countries there is a bias towards N-based fertilizers (Table 3).

Table 3. Nutrient Consumption Ratio

(Source: FAO, 2005c)

Table 3 shows that in the 1980s East Asia, especially China, dominated in the field of N-based fertilizer use. However, in recent years the bias towards N-based fertilizers has increased in South Asia too. Both regions show a greater bias towards the use of N-based fertilizers than developed countries and world averages (Table 3). In South Asia, especially India, despite the introduction of a price concession on P and K fertilizers and other measures taken to increase their consumption, the ratio (N:P:K) remained wide and in 1996/97 it was 10:2.9:1. Subsequently, it has tended to improve, reaching 6.9:2.6:1 in 2003/04. The following Table 4 has been added to demonstrate that not only there are variations in the NPK ratio within countries but even within the countries the variation is large. For example, in India the yield growth in the northern zone, where farms are large and mechanised, is more due to N-based fertilizers than other parts of India where the farms are small subsistence farms.

Table 4. Consumption of fertilizers by state 2003/04

It is not appropriate to propose an 'optimum' N:P:K ratio which is appropriate for all crops in all countries, since, as stated above, this will vary according to soil analysis. Initially applications of P and K may need to be large in order to build up soil reserves of these nutrients. Soil reserves of N cannot be built up in this way since plant-available N is soluble and in regions where over-winter drainage occurs will be lost by leaching after harvest. Thereafter, fertilizer applications may be broadly related to the nutrients removed in crops at harvest. For cereal crops this ratio is c. 1.5:0.75:1 when straw is removed and c. 3.0:1.5:1 when straw is incorporated into soil (Archer, 1985). These rations will balance nutrients removed in crops but will not redress any imbalances in soil nutrient reserves.

2.1.3 Increase in crop yield through use of water and irrigation

Water is essential for plant growth and 62% of water use in the developed world and 85% of water use in the developing countries are for agricultural irrigation. Irrigation is primarily used to increase crop yield, but in particularly arid areas may be needed to enable any plant growth. Irrigation can be large scale through extensive centralised canal networks or it can be small-scale activity through locally managed tube-wells. A number of other informal means of managing rainwater efficiently are also used. More than 80% of cereal area in developed countries is rain-fed, producing mainly maize and wheat. The average rain-fed cereal yield in developed countries was 3.2 t/ha in 1995, a figure not dissimilar to that of irrigated cereal yields in developing countries.