Utilization of Moringa Leaves and Pods as Organic Fertilizers in Enhancing Soil Fertility and Crop Growth

Abstract

The use of Moringa extract as bio-fertilizers positively influences agriculture. The different parts of the plant have diverse functions. The extracts have proven to improve crop growth and yield when applied as foliar fertilizers or green manure. The growth and yield of two cultivars of cocoyam (Nce 001 and 012) were enhanced by the application of aqueous moringa leaf and pod extract (AMLE and AMPE). Also the use of moringa leaves as green manure increased the growth of maize. These effects could be traced to its potentials in improving the soil fertility status and also its phyto chemical properties. Therefore, the use of moringa as an organic fertilizer is highly recommended. This book chapter emphasizes the use of moringa leaf and pod extracts, as good alternative bio fertilizers for improved crop growth and yield.

1. Introduction

Moringa is also known as Horse-radish tree or drumstick tree. It is a shrub or tree belonging to the Onogenic family, known as Moringaceae. The tree is indigenous to Agra and Oudh in India’s North West, south of the Himalayas. It is cultivated worldwide, particularly in Pakistan, Asia Minor, Africa, and Arabia, [1]. At the start of the 20th century, it was brought from India to Eastern Africa. The Moringa oleifera Lam. species is the most widely grown of the 13 species that make up the moringa family. Moringa grows fast into a short, slender perennial tree, about 7–9 m tall, and can grow up to 6–7 m within a year under low rainfall of at least 400 mm/annum [2]. The bark is grey and thick, and looks like cork, peeling in patches. Propagation is either by seed or vegetatively through cuttings. When the moringa plant is 8 months old, it starts to bloom, and the flowering season lasts from January to March. The triangular (30–50 cm long) pods of the fruit, which ripens between April and June, have oily, black winged seeds inside [3, 4]. It has long tuberous tap roots that grow deep into the soil in order to absorb nutrients from the subsoil during the dry season. The moringa tree is renowned for its ability to adapt to difficult growing conditions that most trees cannot handle, including resilience to diseases and drought [5]. In the sub-Saharan regions, moringa is a relatively new crop for farmers, and it is primarily produced in backyards for domestic consumption. However, there is little information available on farmers’ perspectives of its production, processing, and use.

Moringa is quite interesting to scientists since it possesses beneficial qualities and traits. These include the high levels of protein found in the leaves and stem, the oil found in seeds, and the abundance of distinctive polypeptides found in seeds that can bind to various moieties. Since ancient times, its traditional, medical, and industrial uses have been promoted. The plant’s varied sections are excellent providers of protein, vitamin B, amino acids, and numerous phenolic compounds. They also include profiles of significant minerals [3, 6]. Phytochemicals found in the moringa plant are abundant and unusually combined [7].

Owing to its numerous usages and advantages for agriculture and industries, Moringa oleifera Lam. has received a lot of attention recently [8]. All parts of the moringa plant are utilized for medicinal and other reasons, earning it the nickname “wonder tree.” Moringa has antibacterial qualities in its bark, seeds, roots, stem, leaves, and flowers [9, 10]. Moringa has in recent times been studied for its potential to increase soil fertility, crop growth and production, making it a valued plant [11]. Because it includes several plant hormones that promote growth, moringa extract has demonstrated to boost crop development and productivity when used as foliar fertilizers or green manure. Due to their involvement in all phases of plant growth and development, plant hormones have the potential to increase yield. Auxins, gibberellins, abscisic acid, ethylene, and cytokinins are examples of growth-regulating hormones [12]. One type of cytokinin that naturally occurs in plants is zeatin. Fresh moringa leaves have a high zeatin concentration, according to studies [13]. Onions, pepper, soy beans, sorghum, coffee, tea, melon, and maize leaves were sprayed with moringa leaf extract, and it was discovered that doing so increased their yield [14]. Moringa has been reported to have high yielding and drought resistant qualities with its mean annual pod yield capacity of 37.69 tonnes/ha/yr. and seed yield capacity of 16.74 tonnes/ha/yr., and was also reported to have grown and yielded very well in the arid savannah zones [15]. The fertility of agricultural soils is increased by using moringa shoots as green manure. For this, moringa seeds are planted in well-prepared seed beds 10 cm apart and 1–2 cm deep. After 25 days of planting, the young plants are ploughed into the ground at a depth of 15 cm [3].

2. Moringa production

Moringa seedlings for transplanting are grown in seed bags of about 18 cm in height and 12 cm in diameter. The suitable soil medium is a mixture of topsoil, manure and fine sand in the ratio of 3:2:1. Three seeds are planted per bag at a depth of 2 cm. The seedlings are thereafter transplanted one month after sowing. Before transplanting, holes with dimension of 30 cm wide and 30 cm deep are dug at a spacing of 20 cm × 50 cm. The holes are then half-filled with the soil medium to sustain the seedlings at the early stage of their growth. The moringa seedlings are transplanted with their ball of earth and watered routinely. One month after transplanting, the moringa plants are trimmed using a pruning saw to promote branching, increase yield and facilitate harvesting. Six months after transplanting, when the pinnules would have been broad enough, the leave can be harvested for processing by snaping leafy stems from branches. Young shoot tips can be harvested to promote the development of side branches. The plant should be allowed to develop new shoots and branches before subsequent harvest.

3. Economic importance of moringa

Moringa is an all-purpose plant. There are numerous uses for every component of the plant. The leaves are highly nutritious. They are good suppliers of phenolic compounds, beta carotene, minerals, vitamins, amino acids, and protein. Zeatin, quercetin, beta-sitosterol, caffeoylquinic acid, and kaempferol are all present in them in rich and uncommon combinations. They act as cardiac and circulatory stimulants. They possess antibacterial, antifungal properties and some antioxidants. The leaves are ground and used for scrubbing utensils and for cleaning walls. The fresh leaves can be eaten raw or cooked like spinach or dried and made into powder that can be added to sauce etc., and young branches are eaten by livestock. It is planted as living fence tree.

The young green pods can be eaten whole and be comparable in taste to asparagus. The older pods can be used for their seeds, which can be prepared as peas or roasted and eaten as peanuts. The seeds yields about 40% of non-drying oil, known as Oleic or Ben oil, used for cooking, lubricating, cream and soap making etc. The oil is clear, sweet and odourless and also useful in the manufacture of perfumes and weavon oils in hair dressing [16]. The oil compares favourably with olive oil. The mature seeds can also be used to purify water. Seed cake is a good source of fertilizer, however it is not advisable to use the seed cake for livestock feed as it contains alkaloids and saponin [17].

The flowers bloom around 8 months after planting. They are present all through the year and serve as good source of nectar for honey producing bees. Thus, their presence enhances growth of other crops due to increase in pollination activities by bees. The flowers can be eaten fried and have the taste and texture of mushrooms. Moringa wood yields a blue dye and the bark can serve for tanning.

4. Agricultural benefits/application of moringa

There are also many other uses of moringa especially in the agricultural sector, among these are;

4.1 Animal feedstock

There are significant nutritional restrictions on ruminant feed in many tropical areas due to low-quality and insufficient natural foods, which can result in an energy and protein shortage [18, 19]. The problem of ruminant feed shortages is made worse by the dry seasons, when natural pastures are deficient in protein and energy. Moringa has a high nutritional content and might be a suitable source of feed supplement, according to several research [20, 21]. Therefore, using moringa as a source of protein will boost cattle performance and balance other available nutrients [16].

4.2 Alley cropping

With the rapid growth, long tap roots, few lateral roots, minimal shade and large production of high-protein biomass, moringa trees are well suited for use in alley cropping systems.

4.3 Green manure

Moringa plants can be cultivated intensively and then ploughed back into the soil, as green manure or natural fertilizers for other crops. The leaves could also be pruned and incorporated into the soil as green manure. The incorporation of fresh or dry moringa leaves has been reported to increase the soil organic matter, nitrogen and phosphorus contents and reduced exchangeable aluminium and hydrogen ions. Among fresh and dry moringa leaves incorporated into the soil, nutrient release was higher in the dry than the fresh leaves. The incorporation of 5–15 t/ha fresh and dry moringa leaves enhances Maize growth and production [22].

4.4 Foliar nutrients

The juice extracted from the different parts of the plant especially the fresh leaves and pods can be used to make foliar fertilizers capable of increasing crop yield by up to 30%.

In an experiment conducted by Ebido et al. [23], fresh leaves and pod husks of Moringa oleifera were collected and washed under tap water; rinsed with distilled water and dried in shade. The dried samples were powdered in a hammer mill grinder. Powders of the leaves and pod husks were mixed separately with distilled water in a ratio of 100 g: 1 lit and left overnight to allow the powder get dissolved in water. The mixture was then filtered through muslin cloth to get 100% moringa plant tissue extract. The extracts were shaken after vacuum filtration. The undiluted extracts were added to the Erlenmeyer flasks, blocked with cotton individually, and heated at 50°C for 15 min to prevent contamination. To further dilute the extracts for usage, two ratio concentrations 1:1 and 2:1 (i.e., 5 ml of extract to 5 ml of water and 10 ml of extract to 5 ml of water, respectively) of distilled water were used.

5. Use of aqueous moringa leaf and pod extracts (AMLE and AMPE) as foliar fertilizers and the effects on crop growth and yield

In a field evaluation trial, Ebido et al. [23] studied the effects of aqueous moringa leaf and pod extracts (AMLE and AMPE) on the growth and yield of cocoyam. The trial was done at the Cocoyam Experimental Farm of National Root Crop Research Institute, Umudike, Abia State, South-East Nigeria. The experimental site was located in the rainforest agro-ecological zone. The soil was a coarse-textured Ultisol. The processed moringa leaf and pod extracts were further diluted with distilled water at the ratios of 1:1 and 2:1 using 5 ml of extract to 5 ml of water and 10 ml of extract to 5 ml of water respectively. The crop used for the experiment was cocoyam (Colocasia-NCe 001 and NCe 012). A month after planting, the treatment application began, and it was repeated monthly. Plant stand at harvest (survival count) was the growth data measured. Number of corms, number of cormels, weight of corms (kg), weight of cormels (kg), total number and weights of corms and cormels after final harvest were the yield components measured.

The results, as displayed in Tables 1–3, demonstrated that the AMPE provided a higher yield than the AMLE. All of the treatments produced higher yields when compared to the control, with AMPE 2:1 having a higher yield of about 20% on NCe 012 and AMPE 1:1 having a higher yield of nearly 50% on NCe 001. There were notable yield variations between the two cultivars, with NCe 012 doing better.

Treatments	Survival counts	No. of corms	Weight of corms (kg)	No. of cormels	Weight of cormels (kg)	No. of corms and cormels	Total weight (kg)
T1 (Con)	14.0a	16.3b	0.9b	109.0a	2.2a	125.7a	3.1b
T2 (AMLE 1:1)	14.3a	17.0b	2.0b	143.7a	3.9a	187.3a	5.9a
T3 (AMLE 2:1)	16.7a	24.0ab	1.2ab	163.0a	3.4a	160.7a	4.6ab
T4 (AMPE 1:1)	17.7a	32.0a	2.1a	156.7a	4.1a	188.7a	6.2a
T5 (AMPE 2:1)	14.3a	16.7b	1.2ab	145.0a	3.3a	161.7a	4.5ab

Table 1.

Effects of aqueous moringa extracts on cocoyam (NCe 001).

T = treatments, AMPE = aqueous moringa pod extract, AMLE = aqueous moringa leaf extract, means with the same alphabets are statistically similar.

Source: Ebido et al. [23].

Treatments	Survival counts	No. of corms	Weight of corms (kg)	No. of cormels	Weight of cormels (kg)	No. of corms and cormels	Total weight (kg)
T1 (Con)	19.3ab	23.7b	2.9b	249.7a	6.0a	273.3b	8.9a
T2 (AMLE 1:1)	16.3b	32.7a	3.6ab	273.0a	6.5a	305.7ab	10.1a
T3 (AMLE 2:1)	19.0ab	31.7ab	3.3ab	270.7a	6.4a	302.3ab	9.6a
T4 (AMPE 1:1)	16.7b	30.3ab	2.9b	267.0a	6.2a	397.3a	9.1a
T5 (AMPE 2:1)	20.0a	38.3a	3.9a	316.0a	7.2a	354.3ab	11.1a

Table 2.

Effects of aqueous moringa extracts on cocoyam (NCe 012).

T = treatments, AMPE = aqueous moringa pod extract, AMLE = aqueous moringa leaf extract, means with the same alphabets are statistically similar.

Source: Ebido et al. [23].

Treatments	Survival counts	No. of corms	Weight of corms (kg)	No. of cormels	Weight of cormels (kg)	No. of corms and cormels	Total weight (kg)
NCE 001	15.7	22.2	1.5	150.8	3.5	173.1	4.9
NCE 012	20.6	33.2	3.4	276.8	6.5	309.9	9.9
LSD (0.05)	1.5	3.9	0.4	37.6	0.8	38.3	1.2

Table 3.

Yield performance of the two cocoyam cultivars (NCe 001 and 012).

Source: Ebido et al. [23].

This demonstrates that using moringa extract as an organic foliar fertilizer substitute can increase cocoyam yield. This can be likened to the presence of growth enhancing hormones, especially cytokinin (Zeatin) in AMLE and AMPE which increases growth and yield of crops [3, 7, 13]. It had been reported that foliar application of moringa leaf extract improved the growth and yield of tomatoes, peanut, corn and wheat during the vegetative growth stage of the crops. Fuglie [3] reported yield increase of 25–39% in onions, pepper, soya, maize, sorghum etc. following the application of moringa leaf extract. Similarly, Phiri [24] observed that M. oleifera leaf extract improved germination of sorghum and increased hypocotyl length of wheat. Adekiya et al. [25] pointed out that the application of moringa leaf extract increased the yield of okra when compared with the control.

6. Conclusion

The use of plant extract as bio-fertilizers has proven to influence agriculture positively. Moringa, which is referred to as a Miracle tree, because every part of the tree has great potentials, is no exception of plants whose extracts are used as bio-fertilizers. It grows very fast and can survive unfavourable conditions. It is a global crop because of its adaptability to diverse environmental conditions. The valuable properties and characteristics of moringa have made it a crop of great scientific interest. The different parts of the plant, contain profiles of important minerals, nutrients, hormones and phyto chemicals. Moringa extracts has proven to improve crop growth and yield when applied as foliar fertilizers or even green manure. Reports have shown that the application of moringa aqueous leaf and pod extracts increased cocoyam yield by about 50%. The use of moringa leaves as green manure also increased the growth of maize. These effects could be traced to its potentials in improving the soil fertility status due to its high composition of chemical and phyto chemicals. This, therefore, concludes that moringa extracts, particularly AMPE and AMLE are good sources of alternative bio-fertilizers for enhanced crop yield. Therefore, the use of moringa as an organic fertilizer is highly recommended. Based on the dearth of research on the use of moringa pod extracts for improved crop yield, it is recommended that more research be conducted in this regard.