- Title
- Effects of nitrogen and phosphorus rates, leaf age and drying technique on growth and nutritional contents of Moringa oleifera
- Creator
- Sokombela, Asanda
- Subject
- Moringa
- Date Issued
- 2019
- Date
- 2019
- Type
- Thesis
- Type
- Masters
- Type
- MSc
- Identifier
- http://hdl.handle.net/10353/12117
- Identifier
- vital:39153
- Description
- In general, smallholder farmers tend to use large quantities of soil nutrients without replenishment with manure, compost and fertiliser in order to replace the soil nutrients that are lost. Considering the low soil fertility status of soils in South Africa, this study was conducted with an aim of developing agronomic protocols for the production of moringa in order to fight malnutrition and produce supplement feed for animals. Moringa contains various nutrients and chemicals, such as, protein, which are sensitive to heat, and there is therefore a need to establish the best drying method which does not affect the nutrient content and quality of moringa. Physiological age is probably the most important factor influencing the mineral composition of plants. The relationship between nutrient concentration and leaf age is not fundamentally altered by crop load, soil type, climate or cultural practices, such that nutrients may be displaced vertically by the level of supply. Leaf age is one of the factors that affect the distribution of nutrients in the leaves of plants. Therefore, studies were conducted to evaluate the response of Moringa oleifera leaf yield and nutritional content to nitrogen and phosphorus rates, leaf age/position, and drying techniques. The experiments were conducted at the University of Fort Hare Alice Campus research farm. The experiment that investigated the effect of N and P rates was carried out in potted plants filled fine silica sand. The seeds were sown on black polythene bags, filled with a mixture of soil, pine bark and goat manure (at 1:2:1 ratio, respectively) at a depth of 2 cm. At 30 cm height, the seedlings were transplanted into 5-liter pots, which were filled with building sand as growing media. The experiment was a 4 x 3 factorial, with four levels of nitrogen (100, 200, 300 and 400 kg/ha) and three levels of phosphorus (40, 80 and 120 kg/ha). The experiment was laid-out as randomised complete block design (RCBD), with 12 treatment combinations replicated four times. All experimental units received the same amount of potassium (731kg/ha) in the form of KCl. Nitrogen treatments which were applied were split in two equal applications, at transplanting stage and 4 weeks later. The phosphorus rates were applied as superphosphate once mixed to the potting media before transplanting. Growth parameters such as plant height, root collar diameters, number of leaves, dry and fresh leaf masses were measured. Powdered dry leaves were also analysed to determine iv metabolite such as crude protein, ash, moisture, fat and fibre constituents (ADF and NDF). Micro and macro mineral nutrients were also determined using atomic absorption spectroscopy technique (AAS). The results showed that growth of moringa significantly increased through the application of fertilizer. The results from the (ANOVA) table showed no interaction between phosphorus and nitrogen on growth parameters such as number of leaves, stem width and plant height of moringa in this study. Nitrogen levels, as treatments, have significantly affected the growth of the plant. However, phosphorus, as a treatment, showed no significant difference on growth parameteres of Moringa. It was evident that trees that received the highest nitrogen rate (400 kg/ha) resulted in thickest stem girth, tallest trees and the highest number of leaves. The overall results revealed that moringa leaf powder contained appreciable amount nutrients. Crude protein was notably high (38.23%) in the trees that received the highest phosphorus and nitrogen combination treatment (400 kg/ha N x 120 kg/ha P treatment combination. The highest ash content of (14.17%) and (14.21%) were recorded from the trees that received treatment combination of 200 kg/ha N x 80 kg/ha P and 100 kg/ha N x 120 kg/ha P, and significantly differed from the rest of the other treatment combinations. The fat content steadily increased with an increase in nitrogen rate. Increase in P level resulted in a decrease in fat content. The overall findings confirm that combinations of the higher levels of N and P result in a decrease in fat content. The variation in the metabolite nutrients and mineral nutrient values may be due to differences in age of the leaves or positions and possibly due to different stages of maturity of leaves. The second experiment was conducted in the field at the research farm. The aim was to evaluate the effect of leaf age/position on nutrient distribution of moringa. The seeds were sown in black polythene bags at a depth of 2 cm. The bags were filled with a mixture of 1 part of soil, 2 parts of pine bark: and 1 part of manure. The seedlings were transplanted into the field when they reached the height of 30cm. Plants were laid-out as a CRD design with 5 replications. Three leaf positions, upper, middle and basal leaves, were used as treatments to determine the nutrient variation within a parent plant. Leaves of each position were harvested separately, washed with tap water and air-dried in shade condition. The dried leaves were analysed for metabolite and mineral content. The Association of official agricultural chemists (AOAC) methods were used to determine protein, fat, fibre, and ash. Atomic absorption spectrometry (AAS) technique was used to analyse minerals v such as iron, zinc, copper, manganese and macro-minerals such as calcium, magnesium, potassium, sodium and phosphorus. The study showed that ash, fat, NDF and ADF contents were significantly higher in the basal leaves as compared to that in the middle and upper leaves. However, moisture and crude protein contents were significantly higher in the upper leaves compared to both in the middle and basal leaves. The basal leaves accumulated significantly higher Ca, Mg, K, Na and Mn contents. The concentrations of P, Zn, Cu and Fe were, on the other hand, significantly higher in the younger leaves compared to that in the middle and basal leaves. It can be concluded that the upper (younger) leaves contain enough nutrition to satisfy the dietary requirements. In addition, these leaves have low levels of oxalate, cyanide and nitrate, which can cause health problems. To determine the effect of drying method on nutrition content of moringa leaves, three drying methods (shade-, sun- and oven-drying methods) were applied as treatments. Moringa plants were grown at the Research Farm of the University of Fort Hare, Alice campus. The leaves were harvested, thoroughly mixed, washed with tap water and put into 15 brown paper bags. The 15 samples (paper bags) were distributed to the three drying treatments (each treatment replicated 5 times). The dried samples were analysed for metabolites and mineral content as per AOAC and AAS methods, respectively. The study showed that shade-drying method retained higher metabolites. Thus, this study recommends the shade-drying method in preserving moringa leaves.
- Format
- 180 leaves
- Format
- Publisher
- University of Fort Hare
- Publisher
- Faculty of Science and Agriculture
- Language
- English
- Rights
- University of Fort Hare
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UFH Department of Agronomy
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|---|---|---|---|---|---|---|---|
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