Research Article
Assessment of Seed Germination and Organic Manure Application on the Early Growth of Eucalyptus camaldulensis L. Seedlings

Agera Stephen Iorliam Naishima, Peter Micah Kalu and Amonum Joseph Igba

Research Journal of Forestry, 2019, 13(1), 1-8.

Abstract

Background and Objective: Human population explosion, non-sustainable agriculture and tree logging destroy natural forests, prompting reforestation with fast growing tree species using artificial cultural methods. This study investigated the effects of cow dung and poultry droppings on the germination and early growth of Eucalyptus camaldulensis L. seedlings at the Forestry Nursery in Jos, Nigeria. Materials and Methods: Using the randomized complete block design (RCBD), laboratory-tested soil samples, poultry droppings, poultry droppings plus cow dung, cow dung alone and a control (top soil only) were used in various combinations to assess the growth parameters of E. camaldulensis (seedling emergence, plant height, number of leaves, length of leaves and stem diameter) for 12 weeks. Percentages, means and relative frequency distribution were used to analyze collected data. Results: Results indicated that poultry droppings had the highest nitrogen concentration (3.2%), cow dung (2.9%) and top soil (0.070%). Treatments with poultry droppings gave the greatest plant height, number of leaves and stem diameter (girth) followed by the mixture of poultry droppings and cow dung while top soil (control) recorded the lowest growth. Mixture of poultry droppings and cow dung produced the greatest leaf length, compared to poultry droppings, cow dung and the control, respectively. Conclusion: Thus poultry dropping is recommended as the most suitable organic manure for nurturing juvenile seedlings of E. camaldulensis in the nursery for plantation purposes.

ASCI-ID: 75-100

1. It is a widely used afforestation species due to its fast growth, high productivity and short rotation². The tree grows straight under favourable conditions but can develop twisted branches in drier conditions³. Organic matter is a vital soil component influencing the physical, chemical and microbiological properties of soil to a great extent. Decrease in bulk density with the addition of organic matter has been documented⁴. The use of organic manures enhances increased soil organic matter and total nitrogen (N), increased the effectiveness of soil phosphorous (P), increased population of soil organisms, especially some bacteria and increased activities of some soil enzymes such as urease, improves soil structure, aeration, soil moisture-holding capacity and water infiltration⁵. Manure applied to field plots also risked the subsurface water and groundwater quality if handled improperly⁶.

Organic manure decreases the danger of over-fertilization because the nutrients are released slowly. Using organic fertilizer adds more natural nutrients, feeds important microbes in the soil and improves the structure of the soil⁷. Poultry manure contains a high percentage of nitrogen and phosphorus for the healthy growth of plants⁸. Nitrogen is equally said to be the motor of plant growth⁹. Organic matter is the ultimate determinant of the soil fertility in most tropical soils and this accounts for its use to raise seedlings in tropical areas, the fertility of the soil could be sustained with the addition of poultry manure¹⁰.

Cow dung is a very good source for maintaining the production capacity of soil and enhances the microbial population. It is an important input for maintaining and enhancing soil fertility¹¹. The application of cow dung manure increases soil organic matter content, improves water infiltration and water holding capacity as well as an increased cation exchange capacity. The C: N ratio in cow dung manure is an indication that it could be a good source of protein for the microbes which involved in decomposition of organic matter Dung increased pH, CEC, total N, organic C, loss on ignition and exchangeable Mg and Ca¹². It decreased sulphate sorption. Moreover, cow dung manure plays a significant role in maintaining the nutrient status of the plant. Dung may also be used to produce bio-gas to generate electricity and heat. The gas, rich in methane is used in rural areas of India, Pakistan and elsewhere to provide a renewable source of electricity¹³. This study was conceived to experiment on organic manures as a possible boost to seedling growth in nurseries to enhance decreased rotation period in plantations. The specific objectives were to: (a) Assess the growth responses of Eucalyptus camaldulensis to various application rates of poultry droppings and (b) Assess the growth responses of Eucalyptus camaldulensis to various application rates of cow dung manure.

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MATERIALS AND METHODS

Study area: The study was conducted within the nursery of the Department of Forestry Technology, Federal College of Forestry in Jos, Plateau state. The study area lies in the northern Guinea Savanna situated on latitude 9° 57' N and longitude 8° 54' E with an elevation of about 118 cm above sea level. The mean annual rainfall for the location is between 1200 and 1250 mm and means temperature ranges between 23 and 25°C. The soil is sandy-loam, light to dark in colour. The climate of the state is cool due to its high altitude and rainy season is usually between April and September while dry season is from October-March¹⁴.

Soil sample collection and analysis: All soil samples collected for routine analysis were carefully labeled for identification and taken to the chemistry laboratory of the Federal College of Forestry, Jos where the samples were air dried at room temperature. The air dried samples were then crushed using a mortar and then sieved using a 2.00 mm diameter sieve. The sieved samples were taken to the Agricultural Service Training Center (ASTC), Kassa, Vom, Plateau state, Nigeria for routine analysis. The chemical composition of the soil and organic matter sources, viz: pH, N, organic matter, P, Na, Ca, Mg and K concentrations were assessed using standard procedures as outlined by Soil and Plant Analysis Council¹⁵.

Research design: A total number of 36 perforated polythene bags (20×5 cm) containing 3 kg of soil were laid out in a randomized complete block design (RCBD) with 4 treatments (poultry droppings, cow dung, poultry droppings plus cow dung and a control-without organic matter). Poultry droppings and cow dung were each applied at the rate of 2 kg per 3 kg of soil before sowing¹⁶. The samples that were left without treatment served as the control. The treatments were replicated.

Seed planting, assessment of germination and growth: About 1 g of Eucalyptus camaldulensis seeds obtained from Federal College of Forestry, Jos nursery were planted on each of the soil mixtures by broadcasting and later thinned to one stand per pot 2 weeks after germination¹⁶.

A week after planting, data on seedling emergence was taken to assess the germination. Seedling emergence was taken and recorded from the very 1st day of germination. Plant heigh (cm) was taken weekly from the soil level (base) to the tip using a graduated meter rule. The leaves of every seedling in the replicates were counted and the mean per replicate was determined. Leaf length was measured with a meter rule, stem diameter was measured using a thread, clung around the stem of each seedling and read against a graduated meter rule (in centimeters).

Statistical analysis: The data obtained was subjected to descriptive (percentages and relative frequencies) and inferential one way statistical analysis of variance to determine their significance at 5% level using Statistical Package for Social Sciences (SPSS) version 19. Means were separated using Fisher’s least significance difference (p<0.05).

RESULTS

Chemical analysis of top soil, poultry droppings and cow dung: The pH of the planting media samples in both distilled water and CaCl₂ (paired in brackets, respectively), were slightly alkaline in nature for both poultry droppings (8.20 and 8.0) and cow dung (8.0 and 7.6) while soil pH was slightly acidic (5.95 and 5.35) (Table 1). Percentage nitrogen concentration was higher in poultry droppings (3.2%) than in cow dung (2.9%) and top soil (0.070%). Organic matter content was highest in poultry droppings (58.10%) than in cow dung (28.30%) and soil (2.42%). Phosphorus concentration was highest in the soil (6.30 ppm) than in poultry droppings and cow dung. For exchangeable bases, sodium (Na) was highest in poultry droppings (1.32 ppm) followed by cow dung and soil. The results on calcium, magnesium and potassium were highest in soil than in poultry droppings and cow dung. The soil CEC was 4.05 mMol/100 g.

Effect of organic manure application on germination of Eucalyptus camaldulensis seeds: The effect of organic manure on germination of Eucalyptus camaldulensis seeds is shown in Fig. 1. The germination of Eucalyptus camaldulensis after 1 week of planting showed highest mean percentage germination in poultry droppings treatments and the differences observed were far more significant than the rest of the treatments.

Table 1:	Chemical properties of soil, poultry droppings and cow dung used in potting mixtures
PD: Poultry dropping, CD: Cow dung, Om: Organic matter, LS: Loamy sand N, OM, P, Na, Ca, Mg and K concentrations for poultry droppings and cow dung highlighted in Table 1 is in percentages

Fig. 1:	Effect of different organic manures on germination of Eucalyptus camaldulensis

Fig. 2:	Effect of different organic manures on average number of Eucalyptus camaldulensis leaves

The decreasing order of mean percentage germination were PD (34.9%)>PD+CD (27.1%)>CD (20.1%)>CTRL (18.0%).

Effect of organic manure application on leaf count of Eucalyptus camaldulensis seedlings: The effect of organic manure on average number of Eucalyptus camaldulensis leaves is shown in Fig. 2. The average number of leaves after 1 week of planting had the highest mean percentage value in the poly pot treated with combination of poultry droppings and cow dung (PD+CD). The order of performance on mean number of leaves are was:

PD+CD (27.4%)>PD (26.3%)>CD (23.7%)>CTRL (22.6%)

Effect of organic manure application on height of Eucalyptus camaldulensis seedlings: Figure 3 shows the trends in shoot height growth following application of the poultry droppings, cow dung and poultry droppings plus cow dung on the germination and early growth of E. camaldulensis. Growth values recorded for each treatment increased as the age of the seedlings progressed after seed germinated from 2-12 weeks and the highest value for each stage was obtained from the poly pots treated with poultry droppings (PD) and the order of increase from 2-12 weeks were:

PD>PD+ CD>CD>CTRL

Figure 4 indicates the incremental number of leaves of E. camaldulensis seedlings post-germination. Poultry droppings and cow dung application showed significant differences in the number of leaves formed on the seedlings (p<0.05). The poly pots treated with cow dung gave the highest number of leaves and the decreasing order of number of leaves formed based on treatment was thus:

PD>PD+CD>CTRL

Effect of organic manure application on leaf length of Eucalyptus camaldulensis seedlings: There was a significant increase in length of leaves as the seedling age increased and the highest leave length was obtained from poly pots treated with PD+CD (Fig. 5). The result also revealed highest leave length values between 4-7 weeks for poly pots treated with poultry droppings and order of increase between these weeks were:

PD>PD+CD>CD>CTRL

Effect of organic manure application stem diameter of Eucalyptus camaldulensis seedlings: Treatments with poultry droppings and cow dung were significantly different (p<0.05) (Fig. 6) for stem diameter (girth) of E. camaldulensis between 2-12th weeks.

Fig. 3:	Trend graph on mean effects of application of different manure treatments on plant height of Eucalyptus camaldulensis
	PD: Poultry droppings, CD: Cow dung, PD+CD: Poultry droppings plus cow dung, CTRL: Control, WAP: Weeks after planting

Fig. 4:	Trend graph on mean effects of application of poultry droppings and cow dung manure on number of leaves of Eucalyptus camaldulensis

The results revealed that the values recorded for each treatment increased with seedling age from 2-12th week and the highest value was obtained from the poly pots treated with poultry droppings.

Fig. 5:	Trend graph on mean effects of individual or combined application of poultry droppings and cow dung manure on leaf length of Eucalyptus camaldulensis

Fig. 6:	Trend graph on mean effects of individual or combined application of poultry droppings and cow dung manure on stem diameter (girth) of Eucalyptus camaldulensis
	Source: Field survey

DISCUSSION

The pH in both distilled water and CaCl₂ were slightly alkaline in nature for both poultry droppings while that of soil was slightly acidic (5.95 and 5.35). Percentage nitrogen was higher in poultry droppings (3.2%) than in cow dung (2.9%) and soil (0.070%). These findings are in consonance with Ewulo⁸, who noted that the chemical properties of poultry droppings amended soils for better enhanced plant growth than cow dung manure.

The highest mean germination values were observed in poultry droppings treated poly pots at a rate of 2 kg per 3 kg of soil. The results agree with the findings of Okunomo¹⁷, in Parkia bicolor (A. cheu) production which reported that organic manure, especially poultry droppings could have higher number of seed germination when compared with other source of manures¹⁷. The increase in growth of seedlings with poultry droppings application stressed its importance during the seedling emergence of tree plants¹⁸.

The germination and early growth of Eucalyptus camaldulensis were increased with organic matter application and the highest values were observed in treatments with poultry droppings (PD) followed by the treatments containing poultry droppings and cow dung (PD+CD), cow dung (CD) and the control. The result agrees with findings of Ghanbarian et al.¹⁹ and Bahl and Toor²⁰, who reported that poultry droppings contained higher concentrations of nitrogen and phosphorus. Uka et al.¹⁶ also observed that the application of poultry droppings to Abelmoschus esculentus seedlings more significantly increased the plant height, leaf area, leaf number and fresh weight compared with the application of cow dung manure¹⁶. The highest leaf number of Eucalyptus camaldulensis seedlings recorded under poultry droppings at that period revealed a better performance of these seedlings. This was in agreement with findings by Edmeades and Lafitte²¹ as well as Tindall²², who reported that the reasons for higher performance are attributable to higher nitrogen concentrations.

Poultry manure and cow dung manure were richer in their nitrogen and other nutrient content. This condition created better nutrient absorption which favoured faster vegetative growth. Consequently, highest leaf length was found by PD+CD. This is in consonance with reports recorded by other investigators such as Abou El-Magd et al.³, who stated that the greatest leaf length after trails between October, 2007 and December, 2007 was recorded from poultry manure³.

The result further agrees with Imoro et al.²³, who indicated that both poultry manure and cow dung are valuable sources of fertilizers for the growth of tree seedlings because they have greatly improved growth performance of vegetative parts of treated plants²³.

Stem diameter (girth) of the seedlings was highest with poultry droppings followed by treatment a with mixture of poultry droppings and cow dung, cow dung and control, respectively. This is in line with the findings of Imoro et al.²³, who stated that poultry manure produces better growth attributes such as stem girth than its counterparts produced and this may probably be due to the fact that poultry droppings contains more concentrated nutrients and hence led to enhanced plant growth performance in seedlings of plants treated with poultry droppings²³. This study is also supported by the studies of Okunomo and Bosah²⁴, Amhakhian et al.²⁵ and Okunomo et al.²⁶, who reported the importance of poultry droppings for good growth, stem development and suitability of tree seedlings in terms of mineralization.

CONCLUSION AND RECOMMENDATIONS

The application of poultry droppings alone had the highest effect on the germination and growth of Eucalyptus camaldulensis compared to the combination of poultry dropping and cow dung (PD+CD), cow dung (CD) and control (CTRL). In the nursery management of E. camaldulensis seedlings, poultry droppings is recommended as an organic manure for enhanced fast germination and sustained vigorous growth of Eucalyptus camaldulensis seedlings. Since cow dung has less nutrients compared to poultry droppings, it can alternatively be mixed with poultry droppings to improve on germination and growth of Eucalyptus camaldulensis seedlings.

SIGNIFICANCE STATEMENT

This study discovered that poultry droppings as an organic manure source was richer in nutrients compared to other potting media used. This elevated nutrient status enhanced germination and sustained the growth of the Eucalyptus camaldulensis seedlings better than cow dung and topsoil. This result can help commercial nursery operators to use nutrient-rich organic manure sources like poultry droppings in raising vigorous seedlings in nurseries within a shorter time frame.

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