The physico-chemical and mineralogical characterization of Mg-rich synthetic gypsum produced in a rare earth refining plant

The physical, chemical and mineralogical characterization of the constituents of magnesium-rich synthetic gypsum produced in a rare earth-refining plant located in Gebeng, Pahang, Malaysia was conducted through elemental chemical analysis, scanning electron microscopy with Energy Dispersive X-ray (EDX)-analyzer, thermal analysis, X-ray fluorescence and X-ray diffraction. The crystalline nature of the by-product was studied using FTIR spectroscopy. Elemental analysis confirmed the presence of Ca and Mg, which are essential macronutrients required by plants and this Ca alongside the high pH (9.17) of MRSG may confer on the material a high acid neutralization capacity. From the result, it was observed that the studied by-product is a heterogeneous crystalline material comprising of gypsum (CaSO4.2H2O) and other major components such as calcium (magnesium) compounds (hydroxide, oxide, silicates, and carbonate) and sulfur. These aggregates may contribute to give an acid neutralization capacity to MRSG. The XRD study of MRSG indicated a high content of gypsum (45.4%), shown by the d-spacing of 7.609 Å (2-theta 11.63) in the diffractogram. The infrared absorption spectra of MRSG indicate close similarities to mined gypsum. The results of the characterization indicated that MRSG has valuable properties that can promote its use in amending soil fertility constraints on nutrient-deficient tropical acid soils

Characteristics of magnesium rich synthetic gypsum and its effect as a secondary nutrient source for rubber seedlings on acid soils

Ultisols and Oxisols, the common soil in Malaysia, do not usually contain optimal levels of cations such as K, Ca and Mg, required in large amounts for crop growth and productivity. Thus, the management of input plays an important role in crop production in these widely occurring soils of Peninsular Malaysia. Rubber requires large amounts of nutrients to sustain its growth and production so that faster growth and high latex yield can be achieved and maintained. The use of fertilizer to supply nutrients for rubber is essential in rubber cultivation; however, fertilizer costs account for a larger percentage of production costs. As such, it is imperative to seek for a local alternative source that is cost-effective. Recent studies on MRSG, a by-product obtained from industrial refining of rare earth show that the material contains nutrient elements that may be beneficial for rubber growth in addition to its high pH that ameliorate the impact of soil acidity limitation on crop growth. Therefore, this research was conducted to study the physicochemical characteristics of MRSG, its effect on acid soils, rubber growth, and whether MRSG can be a secondary nutrient source for rubber plants at the growing phase. The characterization results indicated that MRSG has valuable properties that can promote its use in amending soil fertility constraints on nutrient-deficient tropical acid soils. Incubation and leaching column studies were conducted to assess the effect of MRSG on the chemical properties of Ultisol and Oxisol in Malaysia and model the nutrient release pattern from the material over a 6-month period. The incubation experiment was as a factorial experiment consisting of 2 soil types, 3 treatments and five rates including control (0, 1, 2, 4 and 8) and laid out as a completely randomized design (CRD). For the leaching experiment, the treatment consists of 1 t ha-1 of MRSG, GML and kieserite with three replications arranged in a complete randomized design (CRD). The study comprised two soil orders viz Ultisol and Oxisol belonging to the Bungor and Segamat series based on Malaysian classification for local soils. The amount of nutrients released into soil solution and present on the soil exchange site due to the application of MRSG at various rates and months were fitted into different functions using python programming script. The pattern of nutrient release from MRSG was similar in the two studied soils and amounts of nutrient released increased with the duration of the experiment. Nutrients release kinetics for all samples are adequately described by the parabolic diffusion, power function and Elovich equations. The intercept constants of the equations are strongly positively related to the ratio of nutrients contained in MRSG. The models showed good performance (R2 value in range 0.9 to 0.99) in most samples tested except for the kieserite treatment group. The model indicates that MRSG has a disintegration behavior similar to GML and can be used to achieve a similar result in acid soil amelioration and soil nutrient enhancement. The leaching study showed that MRSG is available in the soil system and can move beyond the zone of incorporation into the sub-soil to further ameliorate subsoil acidity. The Ca and Mg ions contained in MRSG are not easily leached out of the soil profile, thus MRSG can be a potential substitute for lime (GML) on acid soils. For nursery trial to understand the effect of MRSG application on the growth of immature rubber, three-month-old rubber seedlings of the same size and/or height were obtained from RISDA for planting on Ultisol and Oxisol. The experimental units consisted of four rubber seedlings, with a total of 200 seedlings planted in the polybags. Treatments for this study was based on using GML, kieserite and MRSG as fertilizer source to supply the recommended Mg requirement for rubber seedlings in the nursery based on RISDA formulation. Determination of growth parameters of the rubber seedlings was carried out at 3 monthly intervals. The result of the experiment showed that incorporation of MRSG increased the soil pH and decreased the aluminum content. MRSG application also increased the level of available phosphorus and secondary nutrients such as calcium. The growth of rubber seedlings in the glasshouse for the parameters of height, stem diameter, root length and root surface area were significantly enhanced in the two studied soils (Ultisol and Oxisol) by the addition of MRSG which gave a result comparable to other sources of Mg fertilizer. It was observed that plant growth performance was better on the Ultisol compared to the Oxisol. This study showed that the logistic growth curve model in the form of y = A/ (1+be-ct), where y and t were the plant growth parameters and months after transplanting, respectively, while A, b and c were regression constants were biologically fitted in describing the growth in terms of each of the parameters (plant height, stem girth and total plant biomass) versus months after transplanting. At each treatment, the model had an F value with a high approximate probability level at a = 0.0001. In terms of the vegetative growth of the rubber seedlings, MRSG treatments gave comparable results to that of GML and kieserite, thus, indicating the possibility of using MRSG as a replacement of kieserite and GML as Mg source (Mg-fertilizer) to sustain rubber seedling growth

Effect of magnesium rich synthetic gypsum application on ultisol properties and growth of oil palm seedlings

Oil palm cultivation in Malaysia is mainly on the acidic Ultisols and Oxisols, which are highly weathered with low fertility. Despite the problem of low soil productivity, the good physical makeup of the soil makes them suitable for sustainable oil palm cultivation. This study consisted of two parts. The first study was a field work conducted in an oil palm plantation at Bera, Pahang, in an attempt to classify the dominant soil types in the area and to determine their suitability for oil palm cultivation. The second study was a glasshouse trial at Universiti Putra Malaysia using oil palm seedlings planted in polybags, containing Ultisols collected the oil palm plantation. For the field study, a soil pit was dug for profile description on soil morphological characteristics, and samples were collected based on genetic horizons for analyses. Only one soil series was identified in the area under study. The main objective of this study was to evaluate the performance of magnesium rich synthetic gypsum (MRSG) obtained from a rare earth refining company in Malaysia (Gebeng, Pahang) as a potential magnesium source in fertilizer programme for sustainable oil palm cultivation in Malaysia. The soil under study was formed under tropical environment with udic moisture regime on fine-grained sedimentary rocks, mixed with tuffs of Permian age. The soil in the area was reddish in colour, clayey, deep and highly weathered. The clay fraction of the soil was dominated by kaolinite, gibbsite, goethite, and hematite; thus, the plant nutrient status of the soil is low. The exchangeable aluminium in the soil was low, although the soil has an acidic reaction in water. Taxonomically, the soil was classified as Clayey Kaolinitic, isohyperthermic, Typic Paleudult due to its colour and the presence of diagnostic argillic horizon in the B-horizon (Bt). From the results of this study, it was deduced that the inherent soil properties in the field situation had no significant limitation for oil palm cultivation; hence, with proper agronomic practices, the area can be utilized for sustainable oil palm cultivation.In meeting up with the world demand for oil palm products, the industry needs to sustain high productivity. This requires regular application of high amount of fertilizers, one of which is Mg-fertilizer. A glasshouse study for 9 months, using oil palm seedlings, was conducted to examine the effectiveness of MRSG as a source of Mg for oil palm cultivation. In this study, plant performance, nutrient uptake, soil chemical characteristics, and population of soil microbes in comparison with other Mg fertilizer sources, such as ground magnesium limestone (GML) and kieserite (MgSO4.7H2O) were determined. The experimental design was Randomized Completely Block, with 7 treatments and 6 replications, the treatments were: T1- NPK without source of Magnesium; T2 - NPK + Kieserite at standard rate; T3 - NPK + GML at standard rate; T4 - NPK + MRSG at the recommended rate; T5 - NPK + MRSG at one-half the recommended rate; T6 – NPK + MRSG at double the recommended rate; T7 - NPK+ MRSG to equivalent amount of Ca in GML. Soil parameters at 0, 3, 6 and 9 months measured were pH, EC, exchangeable cations, carbon, nitrogen, sulphur and selected micronutrients, while the plant parameters were growth traits, fresh and dry biomass of the seedlings root and above ground portion, macronutrients (Ca, Mg, P, and K) and micronutrient (Zn and Mn). Results showed that there were significant responses among soil to treatments; Treatment (T7) containing 36 gram of Mg i.e MRSG applied at double the recommended rate of magnesium required by oil palm seedlings showed the highest increase of soil pH (6.82), exchangeable calcium (1.52 cmolc/ kg), magnesium (0.59 cmolc/ kg) and total sulphur (0.07 %) in the soil, while the above-measured parameters were lowest in control. The exchangeable aluminium of the soil was low as soil pH under field condition was above 5. GML treatment (T3) was able to increase soil pH that helped enhance oil palm growth. It was found that kieserite (MgSO4.7H2O) treatment had a significant effect on soil fertility, especially in terms of increase in exchangeable magnesium and total sulphur. It was found that MRSG treatments (T4, T5, T6 and T7) had positive effect on soil fertility, shown by the increase in exchangeable Mg, Ca and soil pH. MRSG application did not have negative effect on microbial activities in the soil. Due to the improved soil fertility, the growth of the oil palm seedlings in terms of height, bole diameter, chlorophyll index and root performance was as good as those planted on soil treated with GML or kieserite. As such, Magnesium rich synthetic gypsum can replace kieserite as Mg source for immature oil palm cultivation

Utilization of magnesium-rich synthetic gypsum as magnesium fertilizer for oil palm grown on acidic soil.

A study was conducted to determine the impact of applying different sources of Mg, namely kieserite, ground magnesium limestone (GML) and Mg-rich synthetic gypsum (MRSG) on an acid tropical soil, oil palm growth and production. Besides high amount of Mg and Ca, MRSG contains S. Exchangeable Ca in the untreated soil of the plantation was 0.64 cmolc kg-1, but its critical level to sustain oil palm growth was 0.9 cmolc kg-1. MRSG was applied in the plantation as Mg-fertilizer; however, since Ca is also a limiting nutrient, oil palm growth was correlated (r = 0.69) with Ca supplied by the MRSG. Mg needed to sustain oil palm production is normally supplied by kieserite. Its requirement can be met at a lower cost compared to that of the kieserite by using MRSG. Due to MRSG treatment, exchangeable Ca in the soil increased steadily to satisfy the requirement of oil palm for fruit bunches production. From the glasshouse and field study, it was observed that MRSG applied at 1.5 times the recommended rate gave results comparable to that of the kieserite. MRSG treatment resulted in the increase of soil pH to >5 that precipitated Al3+ as inert Al-hydroxides, which eventually enhanced oil palm seedlings growth. Thus, MRSG can also replace GML to increase soil pH and satisfy the Ca and Mg requirement of oil palm. It can be concluded that MRSG has the potential to be used as a source of Mg as well as Ca for oil palm grown on acidic soil

Morphological and molecular diversity of eggplant accessions (Solanum melongena L) using simple sequence repeats (SSR) markers

The evaluation of various desirable traits in eggplant genotypes has facilitated the efficient process of selecting and improving them. Morphological parameters have proven to be valuable in assessing the similarities or differences among different accessions, while molecular data have been used to support the conclusions drawn from the morphological analysis. This study was conducted to evaluate the performance of 42 eggplant genotypes collected from Malaysia, China, and Thailand. The characteristics under investigation were shown to be highly significant (p < 0.01) by analysis of variance (ANOVA). It was noted that the plants TV17 (5.59 kg) and MV18 (5.97 kg) produced large yields per plant. The SSR markers used exhibited moderate average values for the number of alleles (2.53). The major allele frequency displayed a high average value (0.53) and a moderate average number of effective alleles (2.31). Additionally, the observed Shannon’s information index, expected heterozygosity, and PIC were high (0.84, 0.54, and 0.45, respectively). Using the unweighted pair-group approach with arithmetic averages based on similarity matrices (UPGMA) Dendrogram, 42 accessions were sorted into five primary groups based on similarities. The findings of this study indicate that the use of simple sequence repeat (SSR) markers can effectively estimate genetic diversity and analyze phylogenetic relationships. Moreover, these markers can assist eggplant breeders in selecting desirable quantitative traits within their breeding program

Morphological and molecular diversity of eggplant accessions (Solanum melongena L) using simple sequence repeats (SSR) markers

The evaluation of various desirable traits in eggplant genotypes has facilitated the efficient process of selecting and improving them. Morphological parameters have proven to be valuable in assessing the similarities or differences among different accessions, while molecular data have been used to support the conclusions drawn from the morphological analysis. This study was conducted to evaluate the performance of 42 eggplant genotypes collected from Malaysia, China, and Thailand. The characteristics under investigation were shown to be highly significant (p < 0.01) by analysis of variance (ANOVA). It was noted that the plants TV17 (5.59 kg) and MV18 (5.97 kg) produced large yields per plant. The SSR markers used exhibited moderate average values for the number of alleles (2.53). The major allele frequency displayed a high average value (0.53) and a moderate average number of effective alleles (2.31). Additionally, the observed Shannon’s information index, expected heterozygosity, and PIC were high (0.84, 0.54, and 0.45, respectively). Using the unweighted pair-group approach with arithmetic averages based on similarity matrices (UPGMA) Dendrogram, 42 accessions were sorted into five primary groups based on similarities. The findings of this study indicate that the use of simple sequence repeat (SSR) markers can effectively estimate genetic diversity and analyze phylogenetic relationships. Moreover, these markers can assist eggplant breeders in selecting desirable quantitative traits within their breeding program

Effects of grafting on morphophysiological and yield characteristic of eggplant (Solanum melongena L.) grafted onto wild relative rootstocks

Grafting is regarded as an integral component of sustainable vegetable production. It is important in the management of soil-borne diseases, and reports suggest that grafting with viable rootstocks can enhance crop growth and yield. This research was conducted using splices and cleft grafting techniques to investigate graft compatibility among varieties of high yielding eggplant scion (MCV1, MCV2, CCV1, CCV2, CCV3, NCV, and TCV) grafted onto wild rootstocks (MWR, BWR, and TWR) to study their morphophysiological and yield characteristics. High yielding scions grafted onto wild relative rootstocks were compared with two controls including self-grafted and non-grafted. All the scion had a high rate of germination (≥95%) and remarkable graft success (100%) was recorded in MCV1, MCV2, and TCV using the cleft techniques. Generally, the use of rootstocks resulted in higher total and marketable fruit yield compared to the non-grafted and self-grafted scion plants, respectively. In particular, MWR and TWR rootstock conferred the highest vigour to the scion, resulting in the highest values recorded for total and marketable fruit yield, number of fruits per plant and average fruit weight. A similar result was obtained in fruit length and diameter, where long and wide fruits were observed in scions grafted onto MWR and TWR rootstocks, respectively. Grafting of high yielding eggplant scion onto resistant MWR, BWR and TWR eggplant rootstock was found to be beneficial for eggplant cultivation. The remarkable compatibility and vigour of the rootstock with scion led to the improvement in total and marketable yield of the fruits. As such, it can be concluded that the use of wild relative rootstocks of eggplant species can be a valuable method of improving eggplant production