Aims: Agriculture is the main source of soil degradation processes in Bulgaria. Therefore the re-cultivation of soil is an important task. The possibilities for using composted municipal waste for soil re-cultivation in Bulgaria are discussed on the case of plant processing municipal solid waste in Plovdiv. Presentation of Case: The plant for processing of municipal waste with capacity 125,000 t/yr built in the neighbourhood of Plovdiv is presented. The case study has been prepared in the Department of Agro chemistry and the Department of Mathematics, Informatics and Physics of the Agricultural University, Plovdiv in collaboration with the National Biomass Association between March 2013 and August 2013. Discussion: Bulgaria has a good infrastructure and an adequate waste management framework. About 85% of the generated waste is transported to the depots and approximately 52% of the total amount of waste is biodegradable. Plant for processing of municipal waste with capacity 125 000 t/yr is built in Plovdiv region. The installation is designed for the processing of municipal solid waste in Plovdiv and other regional municipalities. After primary separation of the components of municipal waste the organic component is used for composting. Data about compost content are presented because of its importance for the re-cultivation. Conclusions: The processing of municipal waste for producing compost of organic origin that can be used for soil re-cultivation (to recover nutrients and improve structure) allows reducing the area of dunghills, unpleasant smell, and Greenhouse Gas emissions.
Two experiments were conducted about the effect of the application of phosphorus (P) or silicon (Si) on the arsenic (As) contents of Japanese mustard spinach (JMS) (Brassica rapa var. perviridis) grown on As contaminated soil (30.6 mg As kg-1). The P was applied with four different P fertilizers derived from both organic or inorganic sources viz. chicken manure (CM), bone powder (BP), fused magnesium phosphate (FMP), and super phosphate (SP). The P was applied at two rates (50 and 100 kg citrate soluble P2O5 ha-1). The As contents (mg kg-1 dry weight [DW] and/or µg plant-1) in the edible part of JMS reduced significantly as compared to the As contents in control plant with the application of P, irrespective of the form of fertilizer and to the application rate of P. There was no significant difference among the P fertilizers as well as the rate of P application in reducing As contents in the plant. The growth of the plant and P concentration in the plant part increased significantly with the application of P. In the Si application experiment, Si was applied from three different sources viz. potassium silicate (PS), magnesium trisilicate pentahydrate (MTP) and lherzolite (LE). Silicon was applied at the rate of 1,050 kg SiO2 ha-1. The As contents in the edible part of JMS increased, but not significantly, as compared to the As contents in control plant with the application of Si irrespective of the source of Si. There was no significant difference in the As contents in the edible part of the plant among the Si sources. The magnesium content in the plant part was increased significantly with the application of MTP and LE. The growth of the plant and the other mineral concentrations in the plant part was statistically similar as compared to the control plant. The results of two experiments indicated that the application of P could reduce the As contents in the edible part of JMS whereas Si had no effect to reduce As content in JMS under the employed condition.
The impact of sole poultry manure (6t PM ha-1), sole NPK (200kg NPK ha-1) and their combinations (3t PM + 100kg NPK ha-1 and 1.5t PM + 150kg NPK ha-1) on sweet potato yield parameters and soil nutrients was assessed at Adiembra and Fiaso in Ghana between June, 2011 to November, 2011 using RCBD. Nutritional levels of the sweet potato tubers and the amended soils were analysed with standard laboratory procedures. The 3t PM + 100kg NPK ha-1 produced significantly (P=0.05) the highest tuber yield (tonnes ha-1), tuber length and diameter, and also had the highest percentage of marketable tubers. The total percentage soil nitrogen, organic matter, Total Base Saturation (TEB) and Effective Cation Exchange Capacity (ECEC) were significantly (P=0.05) highest in the 6t PM ha-1 treatment. The 6t PM ha-1 treatment had the highest tuber nutrient values for Ca, Mg, P, S and N. The 3t PM + 100kg NPK ha-1 had the highest cost benefit ratios of 1:4.38 and 1:8.15 at Adiembra and Fiaso respectively. The results demonstrated that combined application of PM and NPK increased sweet potato tuber yield and soil nutrient levels in a cost effective manner.
A three-year study to determine the initial and residual effects of inorganic and organic fertilizers on potato (Solanum tuberosum L.) and subsequent quinoa (Chenopodium quinoa, Willd) crop performance was conducted in four indigenous communities in the central Bolivian Andean Highland region starting in 2006. The objectives of this research were to identify conventional and alternative fertilizers and combinations of those nutrient sources that improve potato growth and yields and to assess the residual effect of nutrient amendments applied to a previous crop on quinoa as a subsequent crop in the rotation. On-farm trials using local crop management practices had an unfertilized control and separate and combined treatments of local conventional and alternative organic sources (i.e., composted cow and sheep manure, household/urban compost and Biofert, a solid biofertilizer), and inorganic fertilizer (diammonium phosphate + urea). Treatments including inorganic fertilizer alone or combined with cow and sheep manure significantly increased potato tuber yields 67, 68, 79 and 74% over the yield observed in the control plots. The residual effect of these treatments also increased quinoa grain yield 61, 58, 44 and 58% over that of the control. These results are possibly due to the more rapid nutrient availability of applied inorganic fertilizers compared to the application of organic amendments. Increased use of inorganic fertilizers in this region may be necessary because of the reduced availability of organic amendments and the need for improved crop production in both the initial potato crop and subsequent quinoa phase of the crop rotation that depends on residual soil fertility.
For evaluation of moringa growth and its minerals content response to irrigation with diluted seawater and spraying by potassium silicate solitary (Si) or in combination with salicylic acid (Si+SA), a pot experiment was conducted in the greenhouse of the National Research Center, Cairo, Egypt. Negative relationship was shown between salt stress degree and plant growth characters i.e. plant height, leaves area and dry weight of root, stem and leaves, which decreased as the salt concentration increased in the diluted seawater. Nevertheless, shoot/root ratio and leaf water content were increased with salinity increased. All growth characters increased with Si+SA addition. While adding sole silicate gave more plant height than the combined application without significant difference between them. The highest positive effect was shown when plants irrigated by tap water and spraying with Si+SA together. Significant depressions were obtained in nitrogen concentration or content as a result of growing moringa plants under salinity condition. Similar response in P content but the differences were not significant. Calcium and K concentrations did not significantly responded with salinity but Mg concentration decreased significantly only with the first level of salinity. Calcium showed its higher increment in content by spraying single Si under fresh water treatment. In most cases, application of potassium silicate in combination with salicylic acid gave the higher increases in mineral content estimated in this work. This means that, a synergistic effect was found between these two materials.
Aims: To investigate the phytoremediation potential of fluted pumpkin (Telfairia occidentalis) for some heavy metals (Cd, Cu, Pb, Cr and Co) in soil. Study Design: The experimental design was based on the assumption of homogeneity of points where the experimental soils were collected. Place and Duration of Study: Department of Chemistry, Nigerian Defence Academy (NDA) Kaduna, Nigeria, between January 2011 and April 2012. Methodology: Surface soil (0 -20 cm) taken from various points of the department were used for the experiment. Pumpkin seeds were planted in polythene bags containing 1.5 kg of the soil which was contaminated with the metals of interest. The experiment consisted of six (6) contamination treatments and a control. These treatments were 5 mg kg-1, 20 mg kg-1, 75 mg kg-1, 100 mg kg-1, 200 mg kg-1 and 220 mg kg-1 of each metal. The soil and the pumpkin tissues (roots, stems and leaves) were analyzed for the metals, eight (8) weeks after planting, through atomic absorption spectroscopic (AAS) method. The physical and chemical characteristics of the soil were also determined. Results: The plant’s shoot length, 8 weeks after planting, showed that Telfairia occidentalis grew better on uncontaminated (control) soil. Generally, the trend showed that the higher the metals level in the soil the shorter was the plant shoot length. The metals (Pb and Co) accumulated more in the shoot than in the roots (Translocation factor- TF > 1) and also than in the soil (Bioaccumlation factor- BF >1). Copper and chromium on the other hand accumulated more in the root and in the soil than in the shoot (both the TF and BF values are less than one). Conclusion: The plant (pumpkin) can tolerate and survive high metals level in soil. It can be used as phytoremediator of soil contaminated with Pb and Co and to a lesser extent Cd.
A field experiment was conducted to evaluate the effect of grasscutter manure (GM), chicken manure (CM), and NPK on soil physical properties, growth and yield of carrot. The treatments were; no fertilizer or manure (control), 300kgNPK/ha (15:15:15), 10tCM/ha, 3 levels of grasscutter manure (10t, 15t and 20t/ha), laid out in a randomized complete block design with 3 replications. Soil bulk density was highest in the control plot while the sole manure treatments had low soil bulk densities, with the 20t/haGM3 having the lowest value. The 20t/haGM3 treatment also recorded the highest values for the gravimetric moisture content and the total soil porosity. Plant height, number of leaves, root length, root diameter and root yield in the amended treatments were better than the control. Values for the growth and yield parameters of the carrot plant from the 20t/haGM3 treatment were in most cases significantly (P=.05) higher than the rest of the treatments, and the 10tGM/ha treatment had better impact on the parameters than the 10tCM/ha treatment. The highest economic benefit was realized for the 20t/haGM3 treatment.
Three pot experiments were conducted to assess the capacity of asclite in reducing arsenic (As) contents in vegetable plants from arsenic contaminated soil. Asclite is an artificially made granular amorphous iron (Fe)-hydroxide material having high ability in adsorbing As(III) as well as As(V). In the first experiment, Japanese mustard spinach (JMS) (Brassica rapa var. perviridis) was grown in a 242 mg As kg-1 soil with 10 and 20% of asclite application. The second and third experiments were conducted in Japan and Bangladesh, respectively, with JMS and Bangladesh spinach (BS) (Spinacia oleracea) grown in a 50 mg As kg-1 soil where 1 and 2% asclite were applied. Application of asclite to arsenic contaminated soil significantly reduced the arsenic concentration in the edible part of the plants as compared to the control plants. The arsenic concentration in JMS reduced by 43 and 60% at 10 and 20% asclite application when grown in a 242 mg As kg-1 soil. The arsenic concentration was reduced by 29 and 37% in JMS, whereas it was 52 and 74% in BS, at 1 and 2% asclite application, respectively, when grown in a 50 mg As kg-1 soil. There was no significant change in the growth and the nutrient elements concentration in the plants. Our findings suggested that asclite could be used to reduce arsenic concentration in vegetables grown on arsenic contaminated soil. Considering the soil type, soil pH, soil arsenic concentration and plant species, further study is required to examine the desirable conditions for reducing the arsenic concentration in vegetable plants with asclite application.