Effect of plant spacing and nitrogen fertilizer levels on the growth,dry‐matter yield and nutritive quality of Columbus grass (Sorghum almum stapf) in southwest Nigeria

A field experiment was conducted in 2006 and 2007 to determine the agronomic performance and nutritive value of Sorghum almum for introduction in the derived savannah area of Nigeria. The experiment was arranged in a 2 × 4 factorial design with 2 plant spacings (0·5 × 0·5 m and 1·0 × 1·0 m) and 4 nitrogen (N) fertilizer levels (0, 60, 120 and 180 kg N ha^?1). Plant height, tiller number, leaf proportion, biomass yield and nutritive value of the herbage were evaluated as part of the search for alternatives (especially drought tolerant) to local forages for dry season feeding of ruminants. Herbage yield data were tested for linear, quadratic and cubic trends to identify the optimal fertilizer levels for both spacings. Spacing × N interactions (P < 0·05) were observed for plant height and tiller number in both years. Agronomic performance was marginally better in 2007 compared with 2006. The maximum dry‐matter (DM) yield of 3500 and 3740 kg ha^?1 for the more dense row spacing (0·5 × 0·5 m) was achieved at N fertilizer levels of 144 and 149 kg N ha^?1 for 2006 and 2007 respectively. For the less dense (1·0 × 1·0 m) row spacing, the maximum DM yield of 3020 and 3240 kg ha^?1 was achieved at 51 and 97 kg N ha^?1 for 2006 and 2007 respectively. The crude protein content of the grass ranged from 61 to 89 g kg^?1 DM, while the neutral detergent fibre (NDF) content ranged from 700 to 734 g kg^?1 DM. The ability of S. almum to persist into the second year in this region is seen as a promising index as persistence is one of the characteristics of a good forage plant. Considering the exorbitant price of N fertilizer, less dense row spacing with N fertilizer rate in the range of 50–100 kg N ha^?1 is hereby recommended for this region.     

Morphological characteristics and nutritive value of some grass species in an arid ecosystem

An experiment was conducted on four genotypes of Cenchrus ciliaris, two genotypes of C. setigerus and one genotype each of Panicum maximum, P. antidotale and Lasirus sindicus grasses at CCS Haryana Agricultural University, Haryana, India in 2003 and 2004. Two cuts were taken in the months of September and November in each year. Measurements were made of seven morphological characteristics and the nutritive value of the grasses. The total green fodder yield was highest in C. ciliaris cv. IGFRI in 2003 and in C. ciliaris cv. CAZRI 75 in 2004. Total dry matter (DM) yield was highest in P. maximum cv. IGFRI and C. ciliaris cv. CAZRI 75 in 2003 and 2004, respectively. Crude protein and digestible DM yields were highest in C. ciliaris cv. CAZRI 75. It was concluded that C. ciliaris cv. CAZRI 75 can be recommended as the one with the most potential among the studied grasses for use in the arid regions of south‐west Haryana, India.     

Effect of defoliation frequency and cutting height on growth,dry‐matter yield and nutritive value of Napier grass (Pennisetum purpureum (L.) Schumach)

Growth characteristics, dry‐matter (DM) yield, chemical components and in vitro dry‐matter digestibility (IVDMD) of Napier grass were studied in a randomized complete block design with three replications at Haramaya University, Ethiopia. The treatments were three defoliation frequencies (60, 90 and 120 d after Napier grass establishment) and five cutting heights (5, 10, 15, 20 and 25 cm above ground level). Except for leaf‐to‐stem ratio, all growth characteristics increased with decreasing frequency of defoliation. Similarly, DM yield of Napier grass increased as the frequency of defoliation decreased. Total ash, crude protein (CP), hemicellulose and IVDMD contents of Napier grass increased with increasing frequency of defoliation, whereas DM, acid detergent fibre, acid detergent lignin and cellulose contents increased with a decrease in defoliation frequency. In contrast, cutting heights had no significant effect on most chemical components and IVDMD contents, although total ash and CP decreased as the height of cutting increased. The CP yield per cut and per day was highest at an intermediate defoliation frequency. The results of this study indicated that Napier grass could be categorized under medium‐ to high‐quality herbage if defoliated at 90 d after establishment in the mid and highlands of Ethiopia.     

Potency of microbial inocula from bovine faeces and rumen fluid for in vitro digestion of different tropical forage substrates

In vitro ruminal fermentation techniques rely on the availability of fistulated ruminants for rumen fluid (RF), a major constraint for resource‐poor institutions. An alternative would be to use faecal microbes. This study was therefore designed to compare the potency of fresh bovine faeces against RF as sources of microbial inocula for fermenting six contrasting tropical forages using the Tilley and Terry (Journal of British Grassland Society, 18 , 104–111) technique. Faecal inocula were prepared at concentrations of 250 g (Faec250), 300 g (Faec300), 350 g (Faec350), 400 g (Faec400) and 450 g (Faec450) fresh cow faeces per litre bicarbonate buffer. In vitro organic matter digestibility (IVOMD) increased with increasing concentration of faeces at 12‐, 24‐ and 48‐h incubation intervals. All faecal inocula except Faec450 had lower potency when compared with RF at all incubation intervals. Digestibility of forage substrates with Faec450 (533 ± 23 g kg^?1 DM IVOMD) was comparable to RF (566 ± 5 g kg^?1 DM IVOMD) after 48‐h incubation. Faec450 showed greater potency on more fibrous and low‐protein substrates than RF. The coefficient of determination of the regression models for predicting 12‐, 24‐ and 48‐h RF IVOMD from Faec450 were 0·914, 0·75 and 0·756 respectively. It was concluded that inocula prepared from 450 g cow faeces demonstrated great potential as a substitute and predictor for RF in 48‐h IVOMD assays of tropical forages.