7. ARABLE LAND

Irrigated land
Cropping intensity
Arable land
Arable land for different cereal feed scenarios

Irrigated land

At present, the irrigated area in all developing countries, including China, makes up about 25 % of the total harvested area. The percentage irrigated area will slowly increase in the medium scenario to some 27% in 2010, 28% in 2025 and 30% in 2050. The increase rate assumed in the medium scenario in all developing countries is about 1 % per year when China is included and even faster at 1.2% per year if China is not included (Table 16; Figure 4).

Based on preliminary FAO estimates, the potential for expansion of irrigation is limited in North Africa. For North Africa there may be water and land available for some additional 2 million ha irrigation (FAO, in prep.). By adjusting the production in North Africa, as discussed in Chapter 2, the expansion of irrigation was limited to levels which are close to the estimated potential (Appendix 19). With the projected increase of 1.9%/yr in the period 1990-2010, and decreasing growth rates thereafter, the irrigated areas in Sub-Saharan Africa do not exceed the estimated current irrigation potential (FAO, in prep.). For the other regions only estimates of the irrigation potential made by FAO (1984) are available. On the basis of these estimates, the irrigation potential will be exceeded in the Near East in Asia. It was assumed that there may be water and land for some additional 10 Mha of irrigation. Similar to the North Africa situation, the domestic production of cereals was reduced in order to avoid inconsistent projections of irrigated and arable land. In the near future the estimates of irrigation potential for all developing countries will be updated.

For South Asia AT2010 assumes a fast growth of 1.3% per year in the period 1990-2010 leading to an increase from the current 76 to 99 million ha in 20 years. Even with the assumed decrease by a factor 2 in the growth rate after 2010, the irrigated area increases by an additional 10 million hectare in the medium scenario between 2010 and 2025. For this region the low scenario is possibly more realistic than the medium and high scenarios. In Latin America the growth rate is high (1.2% per year in the period 1990-2010). Even with this fast increase the irrigated areas remain relatively low in absolute terms and as a percentage of arable land, while the irrigation potential may allow for much faster expansion.

Cropping intensity

The cropping intensity for all developing countries, including China, increases from 87% at present to 94% in 2010 (Table 16). The maximum intensity in the medium scenario is 100%, which is the result of the relative increase of irrigated areas. If China is excluded from the data, the intensity is much lower, close to 80% at present and increasing to 85% in 2010, 88% in 2050 and 92% in 2100 in the medium scenario. The region with most intensive cropping is China and centrally planned Asian countries.

TABLE 16
Total irrigated and arable areas, and cropping intensity for three scenarios for developing countries. The arable area for two feed intensity scenario variants of the medium scenario are also presented. Areas in million ha. Cropping intensity in % of the arable area

		1990	2010	2025	2050	2075	2100
IRRIGATED AREA
All developing incl. China
	Medium	182	226	247	263	275	283
	High		236	261	283	296	303
	Low		212	227	241	248	252
All developing excl. China
	Medium	131	167	185	199	210	217
	High		176	197	216	227	233
	Low		156	169	181	187	191
CROPPING INTENSITY
All developing incl. China
	M	87	94	96	98	101	102
	H		96	99	104	107	107
	L		91	93	94	96	96
All developing excl. China
	M	79	85	86	88	91	92
	H		86	89	92	95	96
	L		83	84	85	87	88
ARABLE AREAS
All developing incl. China
	Medium	836 (851)a	887	918	907	865	885
	High		776	754	701	661	680
	Low		993	1100	1182	1162	1174
	Medium, low feed		874	895	870	824	841
	Medium, high feed		896	947	974	935	962
All developing excl. China
	Medium	726 (742)a	771	794	787	749	772
	High		673	647	599	565	588
	Low		869	960	1042	1023	1036
	Medium, low feed		759	774	755	714	734
	Medium, high feed		780	818	844	809	839

^a The number in parentheses denotes the adjusted number used in AT 2010

In the latter region the intensity is 142% (Appendix 20) calculated on the basis of the FAO yearbooks¹. Assuming a maximum cropping intensity of 140% for irrigated land and using crude estimates for rainfed cropping, overall maximum cropping intensities can be estimated. In none of the regions (except China, as noted above) does the cropping intensity exceed the estimated maximum intensity.

¹ Alexandratos (1995) noted that the actual arable land area may be some 30% higher than the reported area of 109 million ha. Assuming an arable area in China of 125 million ha, the actual cropping intensity may be some 120%. The increase calculated in the scenarios then changes to lower values of maximum ~140% in 2050.

FIGURE 4
Current total irrigated land areas and calculated future irrigated areas for three scenarios. Areas in million ha.

a. East Asia

b. China and C. P. Asian countries

c. South Asia

d. Near East in Asia

e. North Africa

f. Sub-Saharan Africa

g. Latin America

h. All developing incl. China

FIGURE 5
Current total arable land areas and calculated future arable areas for three scenarios. Areas in million ha.

a. East Asia

b. China and C. P. Asian countries

c. South Asia

d. Near East in Asia

e. North Africa

f. Sub-Saharan Africa

g. Latin America

h. All developing incl. China

Arable land

The arable land area is calculated from the harvested areas presented in Appendix 17 and discussed in Chapter 4, and the cropping intensities. For all developing countries, including China, the arable area increases at a rate of 0.3% per year from 836 in 1990 to close to 890 million ha in 2010 in the medium scenario (Table 16; Figure 5). In the years 2010-2025 the arable area increases by 0.2% per year to a maximum area of ~ 920 million ha in 2025, after which a slow decrease occurs close to the 1990 area. If China is excluded from the data, the area increases in the medium scenario at 0.3% per year from ~ 730 million ha at present to ~ 770 million ha in 2010. The arable area increases at an annual rate of 0.2% to a maximum of ~ 800 million ha in 2025, and then begins to decrease. The individual regions show similar results, with an increase in the first 40-50 years, and a stabilization or even a slow decline in the period after 2025 (Figure 5; Appendix 21). Due to the lack of available land in North Africa, the arable area remains constant.

Arable land for different cereal feed scenarios

The effect of the different variant scenarios of the cereal feed intensity on the arable land area is most important in the regions with major livestock production, such as Latin America, and least important in regions with no important livestock production, such as South Asia. Although the high feed demand scenario results in a minor increase in the arable land areas (1% in 2010; 3% in 2025; 7% in 2050), the absolute increase for all developing countries is some 10 million ha in 2010, close to 30 million ha in 2025 and 70 million ha in 2050. It is obvious that the impact of higher feed intensities in the high feed scenario variant grows when livestock production increases. The feed demand scenarios relate to cereals only, and cereals production in all developing countries makes up more than 50% of the total harvested area. This explains the impact of small variations in the cereal feed demand on the arable area in use (Figure 6).

Figure 6 - Effect of cereal feed use on arable land areas of developing countries, including China. Areas in million ha.