Urea and composted cattle manure affect forage yield and nutritive value in sandy soils of south‐central Vietnam

Abstract

Improved forage management can support increased production in smallholder beef systems. Our objective was to evaluate the effects of mineral nitrogen (urea) and composted cattle manure on Brachiaria cv. Mulato II yield and nutritive value in south‐central coastal Vietnam. Study design was a randomized complete block on six farms (blocks), with treatments derived from the factorial combination of five rates of composted cattle manure (0, 4, 8, 12 and 24 Mg DM ha−1 year−1) and three urea rates (0, 60 and 120 kg N ha−1 year−1), split into six yearly applications. Yield was measured from 2011 to 2013 with 36‐day average harvest intervals. Forage nutritive value was measured in September 2011 and December 2012. Highest yields were achieved when both compost and urea were applied at high rates. The initial yield and tiller responses to urea application were not sustained over the duration of the study when no compost was applied. Compost applied in isolation did not increase yield. Compost application increased ash concentration. Urea increased nutrient yield for all forage nutritive value parameters measured. Composted cattle manure combined with urea benefits grass yield, but high application rates are needed for sustained high yields on sandy soils.

Effect of nitrogen application rate on yield, forage quality, and animal performance in a tropical pasture

“…Values of NNI above 1 can increase the production costs and potentially contribute to environmental pollution 47 . Our results differ from the NNI < 1 that was observed when 120 kg N ha −1 year −1 was applied in a Brachiaria pasture in Vietnam 31 . Nutritional status is an effective way to choose the best strategy for pasture fertilization.…”

“…The tiller size/density compensation results in a high amount of leaves produced per unit area 15 that may explain the CP values observed. Similar to the amounts found in our study, higher CP was measured in Brachiaria grass in Vietnam, which ranged from 131 to 170 g kg −1 DM 31 .…”

“…Indeed, to increase CP content, the forage uses carbon to reduce inorganic N for protein synthesis rather than to produce structural carbohydrates 36 . ADF was lower than the values reported for Brachiaria brizantha in Vietnam 31 and in the Cerrado biome 22 . A few other studies also disagreed with our findings 22,32 , wherein a reduction in the ADF content with N application was not observed.…”

“…A few other studies also disagreed with our findings 22,32 , wherein a reduction in the ADF content with N application was not observed. Increasing fertilization levels did not affect dry matter digestibility (P = 0.3539) that was within the range of 550–600 g kg −1 DM for Brachiaria cultivars 22,24,31 .…”

Grazing Intensity Impacts on Herbage Mass, Sward Structure, Greenhouse Gas Emissions, and Animal Performance: Analysis of Brachiaria Pastureland

“…The observed mean CP and NDF contents found in this study varied from 14.0% to 14.7% and from 57.8% to 59.6%, respectively (Table 3). These values differed from several previous studies that used Marandu grass [10,26,27], but were in line with a study from Vietnam [28]. In the Brazilian studies, CP varied from 10% to 12% during the rainy season (November to April), and from 6% to 8% during the dry season, whereas NDF was always above 60%.…”