3.2.4 Fertilizer to Crop Price Ratio
Higher fertilizer to crop price ratio can encourage farmers to use
fertilizer more efficiently, thus increasing nutrient use efficiency in
the cropland (Zhang et al. 2015a, Zhang et al. 2015b). Thus, we expected
a positive relationship between PUE and fertilizer to crop price ratio.
Fertilizer to crop price ratio was positively related to PUE in over
84% of the countries (21 countries) with a significant relationship
(Table 4). These 21 countries accounted for 47% of the global harvested
area, 53% of P in harvested crops, and 65% of fertilizer P input in
2010. In the regression analysis on the global scale, the hypothesis of
a positive relationship was also not rejected (Table 4). These results
indicate a synergy between fertilizer to crop price ratio and PUE on the
global and national scales.