Biomass production of forage grasses in response to nutrient use in Brazil

Brazil is an important beef producer and exporter, with a herd size over 210 million head that occupies 170 million ha of pasture. The national cattle stocking rate is about only 1 head/ha in response to low grazing efficiency, poor soil nutrient management, and lack of technology adoption. Half of Brazil’s pastures are considered to be degraded to some degree. The main causes of pasture degradation are related to adverse soil conditions (low fertility, acidity, and compaction), selecting the wrong plant species (variety adaptation or low tolerance to soil/climate conditions), and inadequate pasture management (weed competition, low seed germination, wrong seeding rate, etc.) This project aimed to study the effect of nutrient application on biomass production of forage grasses in different locations. Also, a case study evaluating the benefit of regular nutrient use in a cattle farm was performed.

Two demonstration plots were carried out in Dracena-SP and Itiquira-MT with eight basic treatments as: (1) control (no applied nutrients); (2) lime application alone (L); (3) phosphogypsum application alone (PG); (4) L plus N application (100 kg N/ha); (5) L plus phosphorus (P) application (45 kg P/ha); (6) L plus potassium (K) application (85 kg K/ha); (7) L plus nitrogen (N), P, and K application (same previous rates); and (8) L+PG plus NPK application (same previous rates). Treatments were set up on a representative local field with the most common type of forage in the region. Nitrogen application alone increased DM yield by 158% and 77% in Dracena-SP and Itiquira-MT, respectively, while NPK application plus liming further increased DM yield in 246% and 92% in the respective locations.

The biomass production of Brachiaria grass in fields with regular nutrient application at a farm located in Jaciara-MT was 77% higher, compared to a field with no nutrient application, allowing a stocking rate to be increased to 6 animal units (450 kg) per hectare.

Two field days were organized in Dracena-SP and Jaciara-MT to present and discuss the results to local farmers, who were impressed with the possibility of achieving higher stocking rates with fertilizer application.