The effect of residual nitrogen fertilization on the yield components, forage quality, and performance of beef cattle fed on Mombaça grass

The objective of this study was to evaluate the effect of residual nitrogen (N) on pastures of Mombaça grass and its impact on pasture structure and the nutritive value and performance of beef cattle. The experiment analyzed randomized blocks subdivided into plots, with three replications. The research focused on a number of pastures having received three annual doses of N (100, 200 and 300 kg ha-1) from 2015 to 2017, with no N fertilization in 2018. The results indicated that pastures under residual effect of 300 kg ha-1 of N were characterized by higher (P<0.05) rates of forage accumulation than those under the residual effect of 100 kg ha-1 N. Furthermore, this study indicated no effect (P>0.05) on the pasture nutritive value and average daily gain (0.490 kg day-1). The stocking rate was higher (P<0.05) in pastures under the residual effect of 300 kg ha-1 of N, and lower in those at 100 kg ha-1 of N, while weight gain per area followed the trend observed in the stocking rate. The results thus suggest that the suspension of N fertilization for one year after three years of sequential fertilization was responsible for an immediate loss of 50 and 55% of the productivity of plants and animals, respectively. Highlights: Fundamental nitrogen fertilization to ensure pasture productivity. The use of nitrogen fertilization has been limited by cost, due to the extension of the areas involved and the need for frequent applications. We suspended nitrogen fertilization for one year after using the same doses of nitrogen for three years in order to evaluate a possible residual effect on plant and animal production. Suspending the N fertilization of Mombaça grass for one year after three years of sequential fertilization with the same doses leaves a residual effect on the pasture structure and performance of beef cattle. The suspension of nitrogen fertilization reduces the rate of forage accumulation by an average of 50%, causing a 55% reduction in animal productivity.The objective of this study was to evaluate the effect of residual nitrogen (N) on pastures of Mombaça grass and its impact on pasture structure and the nutritive value and performance of beef cattle. The experiment analyzed randomized blocks subdivided into plots, with three replications. The research focused on a number of pastures having received three annual doses of N (100, 200 and 300 kg ha-1) from 2015 to 2017, with no N fertilization in 2018. The results indicated that pastures under residual effect of 300 kg ha-1 of N were characterized by higher (P<0.05) rates of forage accumulation than those under the residual effect of 100 kg ha-1 N. Furthermore, this study indicated no effect (P>0.05) on the pasture nutritive value and average daily gain (0.490 kg day-1). The stocking rate was higher (P<0.05) in pastures under the residual effect of 300 kg ha-1 of N, and lower in those at 100 kg ha-1 of N, while weight gain per area followed the trend observed in the stocking rate. The results thus suggest that the suspension of N fertilization for one year after three years of sequential fertilization was responsible for an immediate loss of 50 and 55% of the productivity of plants and animals, respectively. Highlights: Fundamental nitrogen fertilization to ensure pasture productivity. The use of nitrogen fertilization has been limited by cost, due to the extension of the areas involved and the need for frequent applications. We suspended nitrogen fertilization for one year after using the same doses of nitrogen for three years in order to evaluate a possible residual effect on plant and animal production. Suspending the N fertilization of Mombaça grass for one year after three years of sequential fertilization with the same doses leaves a residual effect on the pasture structure and performance of beef cattle. The suspension of nitrogen fertilization reduces the rate of forage accumulation by an average of 50%, causing a 55% reduction in animal productivity

Carbon and Nitrogen Stocks and Soil Quality in an Area Cultivated with Guinea Grass under the Residual Effect of Nitrogen Doses

This study examines the residual effect of nitrogen (N) doses on the carbon (C) and N stocks and on soil quality in an area cultivated with guinea grass. The pastures received three annual doses of N (100, 200 and 300 kg ha−1) from 2015 to 2017. In 2018, N fertilization was not applied so the residual effect of the nutrient could be characterized. Soil chemical attributes, C and N stocks, density and penetration resistance and root system characteristics were evaluated at different depths. No difference was observed between the N doses for soil density, which averaged 1.22 and 1.25 g cm−3 under and between the tussocks of guinea grass, respectively. Penetration resistance was affected by the N doses post-grazing, with the highest value (1.9 MPa) observed in pastures that received 300 kg ha−1 of N for three consecutive years. Root dry mass was not affected by the N doses. There was no effect of N doses on the average (19.7 mg ha−1) or total (134.3 mg ha−1) C stock in the soil. The total N stock did not change (11.3 mg ha−1) in response to the N doses; however, the average N stock was higher in the soil cultivated with guinea grass under the N dose of 300 kg ha−1 (1.7 mg ha−1). The N doses had little interference with the soil chemical and physical aspects. Regardless of the dose, high C and N stocks were observed in the soil cultivated with guinea grass. Therefore, when properly managed, intensive pasture-based animal production systems become important allies of the environment

Effects of Long-Term Crop-Livestock-Forestry Systems on Soil Erosion and Water Infiltration in a Brazilian Cerrado Site

Integrating agricultural land uses is a suitable alternative for fostering economic development and improving food security. However, the effects of long-term integrated systems on soil erosion and water infiltration are still poorly understood. Here, we investigate the influence of different agricultural land uses on soil erosion and water infiltration in an Oxisol site located in the Brazilian Cerrado region. The experimental area consisted of continuous grazing under variable stocking rates with regular fertilization (CG-RF), continuous cropping under no-till (CC-NT) and no-till with 4-year subsoiling (CC-SS), rotation of one year cropping and three years livestock in the livestock phase (C1-L3), rotation of four years cropping and four years livestock in the cropping phase (CL-4C) and in the livestock phase (CL-4L), and integrated crop-livestock-forestry in the cropping phase (CLF-C) and in the livestock phase (CLF-L). To evaluate water infiltration and soil loss, we used a rainfall simulator with a constant rainfall intensity of 74.9 ± 3.6 mm h−1 in plots of 0.7 m2. We carried out 72 rainfall simulations comprising four repetitions in each treatment under vegetation and bare soil. Stable infiltration rate (SIR) ranged from 45.9 to 74.8 mm h−1 and 19.4 to 70.8 mm h−1 under vegetation covers and bare soil, respectively. Our findings indicated that SIR values under CLF-C were 60% greater than under CG-RF. We also found that soil loss rates under CLF-C were 50% smaller than under CG-RF. The crop–livestock rotation period that presented better results of SIR and soil loss was one year of cropping and three years of livestock (C1-L3). Overall, we noted that SIR and soil loss values under CLF-C are similar to the Cerrado native vegetation. Therefore, our study reveals the opportunity to increase agricultural production, improve food supply, and reduce soil erosion with adequate soil and agricultural management