Evaluation of the N supply by soils in La Frailesca, Chiapas, México

Farmers and advisers in this region need science-based recommendations to manage N, which is the main nutrient applied. This project was conducted in 2014 to collect data on the amounts of N supplied by soils that would help in making better estimates of the amounts of N needed to attain yield targets.

Six plots (five rows spaced at 0.8 m by 5.0 m) were marked in seven locations. Half of the plots received normal nutrient management except for N, and the other half had the farmer’s routine nutrient management. Soils have sandy textures, low organic matter, and are generally acidic. Locations 1, 2, 3, 4, and 6 were in close proximity; location 5 was in a separate area with poorer soils, while location 7 is in an area with good soils, distinct from the rest. Nitrogen extracted was estimated using 18 kg N/t grain.

On average, indigenous soil N was 40% of the total N extracted when N fertilizer was applied. Average partial factor productivity, agronomic efficiency, partial nutrient balance, and recovery efficiency were 41 (kg grain/kg N), 25 (kg grain/kg N), 0.5 (kg N in grain/kg N applied), and 0.45 (kg N/kg N), respectively.