Chapter 4. Fertilizer use by crop

The officially recommended rates of fertilizer use for each crop vary according to the water regime and the varieties used (Table 6). In fact, very little information is available on farmers’ decision-making in relation to fertilizer use. Some information is available from farm surveys in the northern Syrian Arab Republic undertaken by ICARDA since the late 1970s. Most of these surveys were designed to analyze farmers’ cultivation practices in general, with some questions directed towards fertilizer use. However two studies concentrated on fertilizer use. The first one Whitaker, 1990) focused on farmers’ fertilizer strategies in northern Syria: the second one (Mazid, 1994) concerned fertilizer use on rainfed barley in the Syrian Arab Republic.

HYV = High-Yielding Varieties. Local = Local varieties.

The majority of farmers make their decisions on fertilizer use without consulting the local extension agent. Some policy-makers have seriously considered making it compulsory for farmers to apply the recommended rates. Although most wheat farmers in the Syrian Arab Republic have used fertilizer for 15 to 20 years, many of them have little information on the recommended rates or the official fertilizer allocations for each crop. They take whatever is allocated to them and rely on their own experience and that of others to decide on their fertilizer strategy.

When farmers make decisions about fertilizer use, they consider the allocation of fertilizer between crops, the number of applications per crop, the rates, timing, and method of application. All of these decisions are made in a highly uncertain environment characterized by wide year-to-year variations in rainfall levels and in seasonal distribution.

For the rainfed farming system, Whitaker (1992) identified several fertilizer strategies adopted by rainfed wheat farmers in northern Syrian Arab Republic. Practically all the farmers surveyed indicated that they applied P₂O₅ only once, at the time of planting (mid-November to early December). Average rates used in the wetter areas (Zone 1) were almost twice the rates applied in the drier regions (Zones 2 and 3). These rates vary very little from year to year since P₂O₅ is applied at the beginning of the growing season, when future rainfall is unknown.

Unlike the case with P₂O₅ application, farmers have greater flexibility with N application. This allows them to modify their strategies depending on rainfall levels.

Wheat farmers in Zone 1 generally apply two dressings of nitrogen. The first application is carried out at planting, the second at around tillering (end of February). As with P₂O₅, N rates at planting time show relatively little variation.

The rates of N for the second application depend greatly on rainfall levels during the first half of the growing season (October to February). If prior rainfall is considered to be normal, then farmers usually apply a rate twice as large as that of the first N application. This rate may be cut by one third if rainfall is below average, or increased by up to 50 percent in a wet year. This depends essentially on the level of previous rainfall and on farmers’ expectations about rainfall during the second half of the growing season (early March to early May).

In the drier zones, farmers are less likely to apply N at planting than in Zone 1 and they tend to use much lower rates. This is a sensible strategy in view of the weather uncertainty. During the growing season, farmers usually apply one to two additional N applications. The number of N applications during the growing season and the rates used per application represent the most important variables that farmers can manipulate in order to adjust the level of application to the amount of rain received. In a normal year, most farmers apply at least one additional N application around the end of January. But if the year should be dry, two thirds of the farmers would not apply additional N during the growing season. In a wet year, more than 80 percent of farmers apply the same rate of N as that applied in normal years. More than half added a third application, about a month later.

Therefore, in the case of rainfed wheat (and rainfed crops in general), rainfall levels and seasonal distribution constitute the main determinants of fertilizer strategies adopted by farmers. In addition to weather, uncertainty about government fertilizer policies also plays an important role in shaping farmers’ strategies. Delays in fertilizer distribution and the size of the allocations are two important factors that influenced farmers’ strategies. One of the most frequently stated complaints was that they often have to delay sowing their cereals or have to plant without fertilization due to delays in fertilizer distribution. Delays also occur during the growing season. In fact, many farmers reported that they would increase the rates and/or the number of N applications during the growing season if the second distribution of fertilizer (allocation for fruit trees and summer crops) were made earlier.

Areas of crops on which fertilizers are used

Table 7 presents the averages of the areas, production and productivity of the main field crops in the Syrian Arab Republic. Table 8 summarizes averages of tree numbers, area, and production of the most important fruit crops in the Syrian Arab Republic. Table 9 summarizes the areas planted to different groups of crops during the period from 1994 to 1999.

Based on informal discussions with farmers and officials, it is estimated that more than 95 percent of the total irrigated area is fertilized at present. Fertilizer use on rainfed crops in Zone 1 increased rapidly and at a faster rate than in Zone 2. However, most of the fertilizer was applied to wheat, with much lower fertilizer use on food legumes. In Zone 3, where barley is the predominant crop, fertilizer use is rather limited.

Farm surveys carried out in 1993 indicated that about 45 percent of farmers in Zones 1 to 3 use either N and/or P₂O₅ on their barley, while few farmers used fertilizer on their rainfed barley in Zones 4 and 5 due to very low rainfall rates. It is tentatively forecast, based on discussions with officials from the Soils Directorate, that the following trends may occur:

• The expansion of the irrigated areas is expected to continue as a result of existing and new government irrigation schemes. These ambitious schemes are expected to increase the total irrigated area by at least 400 000 ha by the year 2010. This should translate into an increase of approximately 50 percent in fertilizer use on irrigated crops. Furthermore, the expected increase in the use of supplementary irrigation on wheat from wells drilled on private farms should also substantially increase fertilizer use.

• An increase of fertilizer use on feed crops and pastures is expected as a result of the expected increases in the demand for feed crops, forage crops and pastures due to the growth in demand for animal products. This demand growth should make the price of feed products high enough to justify the use of fertilizer on most barley areas in Zone 3 and to a lesser extent in Zone 4 and even on natural pastures. Although the rates per hectare used are likely to be relatively low, the area is sufficiently large for the potential increase in fertilizer demand to contribute an additional 20 to 30 percent to total fertilizer use.

• Fertilizer use is expected to increase on fruit tree crops. A continual increase in the price of animal manure is expected to push more farmers, such as olive growers, who have traditionally relied on manuring, to shift to mineral fertilizers. Such a development would have most impact on K2O consumption.