Comparison of Vetiver (Chrysopogon zizanioides L.) Hedges and Traditional Terraces in Water Conservation for Groundnut (Arachis Hypogea) Cultivation in Zalingei, Sudan

Abstract

Field experiments were conducted for three consecutives seasons (2006 – 2007 and 2008) at Zalingei, West Darfur State, Sudan to investigate the effect of vetiver hedges, as water harvesting technique, compared to stone and earth bunds on the growth and yield of groundnut crop and soil moisture content and to study the growth of vetiver grass hedges. Two experiments were carried out each season. In the first experiment, each water harvesting treatment was represented by two barriers (Bunds) constructed 10 m apart per plot. In the second experiment, four barriers, 5 m apart, were constructed per plot. A complete randomized block design with four replicates was used. The size of each plot (micro – catchment) was 20×4 m. The soil of the experimental site was sandy clay loam (Gerdud) characterized by surface crusting, low infiltration tate and high evaporation rate. The following characters were measured for groundnut: Plant height, number of leaves per plant, number of branches per plant, 100 seed weight, number of pods per plant and pods yield. The characters measured for vetiver were plant height, number of tillers per plant and leaf area. A separate sack experiment was carried out to study root growth of vetiver. The results showed that, there were no significant differences between all water harvesting treatments on groundnut in plant height (6.3 – 37.4 cm), number of leaves (15 – 80), number of branches per plant (4 – 11,100), seed weight (28.3 – 31.3 g), number of pods/plant (40 – 46) and pods yield (156.3 – 242.2 kg/ha). There were also no significant differences between the two experiments in the above characters. Soil moisture content ranged between 4 and 19%, with no significant differences among the treatments over the three seasons, whether they were present in two or four rows. The results showed no significant differences between vetiver hedges, present in two or four rows per plot, in plant height, number of tillers and leaf area. The sacks experiment showed that the increase in number of root, which doubled in two months, was greater than the rate of increase in the root length. Although no significant differences were found between vetiver hedges in plant height, number of leaves, number of branches per plant, seed weight, number of pods/plant, pods yield and the other two water harvesting techniques, vetiver hedges were easier to construct and last for years. Water harvesting techniques may have litter impact on crop production in soils with physical conditions not conducive to water conservation. Improvement of soil physical conditions must be sought before embarking on water harvesting