Purpose Date palm (Phoenix dactylifera L.) is one of the predominant fruit trees grown in oases ecosystems (Southern Mediterranean regions) and produces several wastes during practicing cultivation since fruit and bunch thinning is frequently applied. Yet, the valorization of date palm wastes as bioresources has received little attention. The main objective for the present research is to assess palm trees compost (P-compost) as organic fertilizer for alfalfa (Medicago sativa L.). Methods The experiment was carried out in an experimental field involving four replicates and three soil amendment treatments (1) control, conventional mineral fertilizer diammonium phosphate, (2) 30 t ha -1 of cow manure, and (3) 30 t ha -1 of palm tree compost (P-compost). Plots were planted on with alfalfa and the measurements of studied traits (growth, yield, seed yield and minerals uptake) were determined for two crop seasons (2010 and 2011). Results Compared with untreated soil, the palm compost application at 30 t ha -1 improved significantly both organic matter and water retention capacity of the soil and decreased the electrical conductivity (-70%).Furthermore, palm compost supply significantly increased fresh biomass production of alfalfa by 21 and 28%, respectively, during the first and second seasons. Also, it enhanced the grain yield and growth rate (stem length and leafs expansion) of this species. At the first crop season, the palm compost application had a positive impact on minerals nutrition compared to the control treatment, with improving rates of ? 32% for phosphorus, ? 25% for potassium and ? 6% for nitrogen. In addition, these contents were higher than in plants grown under cow manure amendment. However, at the second season, the palm compost improved only P and N contents. Conclusions This preliminary finding suggests that palm compost at moderate dose (30 t ha -1 ) could be highly beneficial for forage plant yield.

Guinea grass (Panicum maximum Jacq., renamed Megathyrsus maximus Jacq.) is a native forage plant in Africa of great economic value, but it was introduced in almost all tropical countries as a source of animal forage. Over the last decade, it was introduced in North arid regions of Africa (Morocco, Algeria, Tunisia, Libya, and Egypt) through authorized and unauthorized ways. It has two reproduction modes through sexual and apomictic ways. Besides its ability to provide high nutritive forage, guinea grass could affect the oases agroecosystems diversity due to its genetic aspects (apomixis and autotetraploidy) and eco-physiological traits (allelopathy effect and resistance to abiotic stress). That is why a review of genetic and eco-physiologic aspects of guinea grass is essential to investigate its potential introduction and management in new regions, particularly in arid and semiarid zones. In this paper, we review the most important traits of this plant that should be considered (polyploidy, apomixis, allelopathic effect, drought and salinity resistance, and invasion) for the potential success of guinea grass in integrated systems of forage/livestock.

Polyploidy plays an important role in plant evolution and constitutes an important mechanism of diversification and creation of genetic variability. Artificial polyploidy can be induced using the colchicine. The aim of this study was to determine the Trigonella foenum-greacum (2n= 16) population which resists better to colchicine treatment and which has the highest rate of polyploid formation among 38 populations collected from different Tunisian regions. The comparative study between treated and control plants showed significant increases (p < 0.05) for the parameters survival rate, rate of malformed leaves appearance, stem height and seeds number by pod. The 38 treated populations showed significant variations (p < 0.05) between them for the parameters survival rate, branches number, stem height and seeds number by pod. Results also showed that treatment of the shoot meristem by colchicine allowed to obtain diploid (2n= 16) and mixoploid plants having mixoploid branches (4n = 32 and 2n= 16) and branches entirely tetraploid (4n = 32). The obtained rate of mixoploidy was 65.79% of treated plants. Among the 38 analyzed fenugreek populations, the population 15 of Menzel Temime presented the highest rate of mixoploids formation and survival rate to colchicine treatment.