Search

Phosphorus deficiency is a major limiting factor in horticultural production. One potential solution can be restoring soil phosphorus from mineral resources, such as solid phosphate sludge (SPS) generated from phosphate treatment processes at mining sites in agriculture. This study explores the possibility of using this sludge in nurseries to produce fruit and forest plants. We tested six mixtures of SPS with the sandy soil of the Maamora forest on ten plant species. In the second experiment, we tested the same mixtures with sea sand. In addition, one concentration of four composts based on phosphate sludge was also tested on two citrus rootstocks and carob. The first experiment's results showed significantly higher growth with the control mixture for pomegranate, acacia, and C. volkameriana plants. The relative growth was higher at SPS concentrations of 20% to 30% for the other plant species, although there was no significant difference between treatments. The estimations of AUGPC (area under the growth progress curve) showed no significant difference in most species. In the second experiment, the relative growth in the M4 (30% of SPS + 70% of sand) mixture was higher, and the AUGCP showed a significant difference compared to the M1 control mixture. The application of solid phosphate sludge positively affects and improves the growth of fruit and forest trees in the nurseries, especially when the concentration is between 20 and 30%. For this purpose, the phosphate sludge could have great potential to be used in nurseries and create a favourable soil condition as a cultivation substrate. [ABSTRACT FROM AUTHOR]

The main environmental challenges of phosphate mines are the huge amounts of waste generated as solid phosphate sludge. These contain a high phosphate rate which is necessary for agriculture production, but chemical parameters as presence of heavy metals and pH make its use possible with limited quantity. In order to be recovered for organic nursery use as a source of phosphorus, different mixtures with organic horticultural wastes in Souss-Massa Region of Morocco were tested in 220-L bioreactors. The objective was to assess the effect of composted phosphate sludge with organic horticultural residues on citrus and forest seedling growth. Solid phosphate sludge with proportions of 41, 29, 35, and 10% (w/w) was mixed with tomato waste, consisting of stems and leaves along with sheep manure (B1, B2, B3, and B7, respectively). Composts were prepared, and 4 weeks after maturity, they were used for plant growth studies using citrus rootstock (Carrizo citrange), carob (Ceratonia siliqua), and argan (Argania spinosa) plants under glasshouse conditions. The experiment was conducted in El Menzeh station of Regional Center for Agricultural Research in Rabat-Sale-Kenitra Region of Morocco. All composts were applied at different concentrations of 0, 5, 10, and 20% (v/v) with sandy soil of Maamora Forest. B7 compost applied at 10% showed significant increase in relative growth of C. citrange plants compared to control soil. Furthermore, application of 5% rate of B3 and B1 enhanced relative growth for argan and carob plants, respectively. Similarly, estimates of the area under the growth progress curves (AUGPC) showed an increase of area when B7 compost of 10%, B3 compost of 5%, and B1 compost of 5% were applied. The study shows that the application of composts as an amendment can increase the performance of substrates which leads to improving citrus and forest seedling growth. [ABSTRACT FROM AUTHOR]