In 1980’s, a soil survey conducted in Tibet revealed that almost all the farmland soils were deficient in N and P but sufficient in K. Since then, only N and P have been considered in the fertilizer recommendations for crop production. Soil test conducted in the recent several years showed that except N, K becomes the nutrient limiting factors in more than 90% of farmland soils sampled. There are only about 22% of soil samples taken from Zha-nang county that were deficient in P as shown Table 1.

Table 1. Evaluation of soil nutrient status in the villages of Jieling and Namsailing, Zha-nang county, Tibet



The fertilizer rates used in the field trials are given in Table 2 where the farmers’ practice was the fertilizer recommendations by the local government

Table 2 Rates of fertilizers used in the field experiments

According to the soil testing data, field trials were conducted on highland barley, winter wheat and some other crops. It is found that, crop yields were reduced significantly without application of K fertilizers (Table 3 and Table 4). But without application of P, crop yield reduction was minor. A number of field trials and demonstrations showed the same trend. Now updated fertilizer recommendations have been made for farmers by adding K and reducing P based on the previous farmers’ practice.

Table 3. Effect of different fertilizer treatments on highland barley in Zha-nang county, Tibet

The yield means following the same letter are not significantly at P<≦0.05.

Table 4 Effect of different fertilizer treatments on winter wheat in Zha-nang county, Tibet


As shown in Table 5 and Table 6, balanced fertilizer treatment reduced fertilizer input by 119.74 Chinese yuan ($US16) and increased income by 1340.74 Chinese yuan ($US168) for highland barley. Similarly, the income increased by the balanced fertilization was 1294.26 Chinese yuan ($US162) for wheat.

Table 5. Yield of highland barley in demonstrations and income of optimum treatment vs. farmers’ practice


Table 6. Yield of wheat in demonstrations and income of optimum treatment vs. farmers’ practice