For decades Malaysia was the world's largest producer of Sn, but now the vast open cast mining operations have left a legacy of some 100,000 ha of what is effectively wasteland, covered with a mosaic of tailings and lagoons. Few plants naturally recolonise these areas. The demand for such land for both urban expansion and agricultural use has presented an urgent need for better characterisation. This study reports on the formation of artificial soils from alluvial Sn mining waste with a focus on the effects of experimental treatments on soil chemistry. Soil organic matter, clay, and pH were manipulated in a controlled environment. Adding both clay tailings and peat enhanced the cation exchange capacity of sand tailings but also reduced the pH. The addition of peat reduced the extractable levels of some elements but increased the availability of Ca and Mg, thus proving beneficial. The use of clay tailings increased the levels of macro and micronutrients but also released Al, As, La, Pb and U. Additionally, the effects of soil mix and mycorrhizal treatments on growth and foliar chemistry were studied. Two plant species were selected: Panicum milicaeum and Pueraria phaseoloides. Different growth patterns were observed with respect to the additions of peat and clay. The results for mycorrhizal treatment (live inoculum or sterile carrier medium) are more complex, but both resulted in improved growth. The use of mycorrhizal fungi could greatly enhance rehabilitation efforts on sand tailings.
This study's primary purpose was to investigate the possible amelioration of limited irrigation conditions by mycorrhiza (AMF), vermicompost, and green manure for lingrain plants. This experiment was accomplished as a factorial based on the completely randomized design with three replications. The first factor was green manure (without green manure and with Trifolium pratense as green manure); the second factor consisted of Rhizophagus irregularis mycorrhiza, vermicompost, a combination of mycorrhiza and vermicompost and none of them, and also the third factor was irrigation regime (full irrigation and late-season water limitation). Green manure, vermicompost, and mycorrhiza single-use enhanced the plant's underwater limitation conditions compared to the control. However, vermicompost and green manure or mycorrhiza developed a positive synergistic effect on most traits. Combining green manure with the dual fertilizer (mycorrhiza + vermicompost) resulted in the vermicompost and mycorrhiza synergistic effects, especially under limited irrigation. Consequently, the combination of green manure, mycorrhiza, and vermicompost experienced the highest amount of leaf relative water content, root colonization, leaf nitrogen, chlorophyll a, chlorophyll b, carotenoids, antioxidant enzymes activity, grain yield, and oil yield, which would lead to more resistance of plants to limited irrigation conditions.
Mycorrhizal fungi are an essential component to consider for better management of soil fertility, particularly in
degraded rangelands of drylands. The present article presents a field survey of colonization and intensity of arbuscular
mycorrhizal fungi (AMF) on prickly pear (Opuntia ficus-indica) roots from young (5 years old) and old (more than 20
years) plantations. The results observed were explained by seasonality and edaphic factors. Prickly pear roots showed
a mycorrhizal frequency (F%) up to 100% of colonization and a mycorrhizal intensity (M%) that may exceed 70%.
According to ANOVAs, both F% and M% varied significantly between Prickly pear plantation ages, but only M% between
seasons. The Generalized linear model showed that edaphic factors have no effect on the variation of F%. However
the statistical model showed that M% were significantly influenced by active CaCO3
, organic matter, carbon, nitrogen,
phosphorus contents and C/N. Our findings highlight the importance of mycorrhization in rehabilitation programs of
degraded rangelands by prickly pear plantations in semiarid and arid lands, particularly during early plant ages and
under environmental abiotic stresses such as climate and soil type.