Tropentag, September 20 - 22, 2017 in Bonn "Future Agriculture: Social-ecological transitions and bio-cultural shifts"

Impact of Forage Management on Yield and Nutritional Quality of Cultivated Forages in North-Eastern Cambodia

¹University of Hohenheim, Inst. of Agricultural Sciences in the Tropics (Hans-Ruthenberg-Institute), Germany
²International Center for Tropical Agriculture, Agrobiodiversity Research Area, Tropical Forages Program, Lao PDR

Abstract

Increasing beef prices present smallholders ready to intensify cattle production in the Ratanakiri Province, Northeast Cambodia, with an opportunity to enhance their livelihoods. One intensification approach, which also reduces pressure on increasingly scarce grazing resources, is to cultivate forages on-farm and use these to feed fenced livestock. The objective of this study was to evaluate if weeding and manuring of farm-grown forages have the potential to increase their yield and nutritional quality.
Above-ground biomass yields of cultivated forages (Brachiaria ruziziensis, B. ruziziensis × B. decumbens × B. brizantha (B. hybrid), Panicum maximum, Paspalum atratum, Stylosanthes guianensis) in Lumphat district (E 106°96´, N 13°57´) were monthly determined destructively during the rainy season between June and September 2015. Forage grasses and S. guianensis were cut at 6 ± 4 cm and 15 ± 7 cm above ground level, respectively. Samples of forages (n = 41) were analysed for their nutrient concentrations. On 20 smallholdings, forage plots of 0.01 ha were weeded monthly, manured with on average 0.24 t N/ha/month, and compared to 0.01 ha non-managed plots.
Maximum yields were measured in P. maximum and P. atratum (3.6 ± 1.5 t dry matter (DM)/ha/month), whereas B. ruziziensis had the lowest (1.1 ± 0.6 t DM/ha/month; P < 0.01). The highest response to management was found in P. maximum and B. hybrid with an average increase of 0.8 t DM/ha/month compared to non-managed forages (P < 0.01). Maximum crude protein concentrations were found in S. guianensis (128 ± 8 g/kg DM), followed by B. hybrid (98 ± 12 g/kg DM), P. atratum displaying the lowest concentrations (65 ± 8 g/kg DM; P < 0.01). Neutral detergent fiber concentrations were highest in B. ruziziensis (668 ± 16 g/kg DM; P < 0.01).
Managing the forages affected their yields more than their nutritional quality. However, selecting suitably adapted forage species rather than intensifying the management of less well-adapted ones may achieve the yields and nutrition necessary to improve cattle productivity. In this context, S. guianensis and B. hybrid had the best potential to supplement rations for ruminants.

Keywords: Above-ground biomass yields, Cambodian smallholders, cultivated forages, nutritional quality

Contact Address: Anna Seidel, University of Hohenheim, Inst. of Agricultural Sciences in the Tropics (Hans-Ruthenberg-Institute), Fruwirthstr. 31, 70599 Stuttgart, Germany, e-mail: AnnaSeidel1gmx.de