Current issue: 54(5)
Under compilation: 55(1)
In the southwestern pre-Saharan arid zone of Morocco, the endemic argan forest (Argania spinosa) had been almost completely destroyed in the 1960s due to intensive coal mining and mixed cereal-livestock farming. These activities turned out to be unviable and a massive rural exodus occurred in the 1970s. Local populations started to develop maintenance-free prickly pear (Opuntia ficus-indica) cultivation at large scale in order to keep their land ownership rights, while reducing their traditional agropastoral activity. We conducted a survey in order to characterize the relationships between the age of prickly pear orchards and argan tree regeneration. We also explored facilitating factors, such as soil organic matter and mycorrhiza. Results showed a high positive correlation (r2 = 0.75, p < 0.001) between the age of prickly pear orchards and argan tree resprouts, but with differences depending on a continentality gradient. The soil organic matter content also showed highly significant differences (p < 0.001) depending on the age of the prickly pear plantation, while spora density did not show such differences. The recent high economic value attributed to prickly pear fruits, and to both argan and prickly pear seed oil, has given farmers the opportunity to develop a lucrative agricultural activity, while promoting the recovery of native vegetation. This situation constitutes a remarkable example of speculative agricultural development in a very harsh environment, in phase with ecological priorities for combating desertification. It could represent an alternative to the externally-generated projects sustained by high levels of public funding, with ecological, economic and social impacts which are sometimes questionable.
A significant amount of land area in the Central Anatolian Region of Turkey has saline-sodic soil properties. The aim of the current study was to use both soil amendment and tree to restore these degraded lands. The primary objective was to ameliorate soils by leaching excess sodium with gypsum and sulfur applications. Following soil treatments, salt cedar (Tamarix smyrnensis Bunge), Russian olive (Elaeagnus angustifolia L.) and silver poplar (Populus alba L.) seedlings were planted on experimental and control sites to evaluate the effects of the treatments on survival and growth of these species. In the fall of 2013, three-year-old seedlings were planted using 1.5 × 1.5 m spacing on each plot. Survival rates were determined and height and diameter were measured at the end of September 2015. Second year infiltration measurements indicated that both chemical treatments had significantly increased the infiltration capacity of the soil (P = 0.0003). Soil infiltration capacity on gypsum treated sites was about 55% higher than on sulfur sites. Following the second growing season, salt cedar had the highest survival rates of 80%. Silver poplar had 36% survival rates across the treatments. Russian olive had 50 cm height growth on both gypsum and sulfur application sites vs. only 25 cm on controls. Diameters of Russian olive on gypsum and sulfur sites were about 9.3 mm vs. 5 mm on the controls. Silver poplars on gypsum treated sites grew 42% taller than controls. Salt cedar had no significant growth responses among treatments. With appropriate soil amendments, especially gypsum, Russian olive gave the best overall two-year results.