ABSTRACT
Three field experiments were conducted between 2018 and 2020 cropping seasons at the Forestry Research Institute of Nigeria (RFIN), Humid Forest Research Station farm Umuahia, and at Itu Ngwa, Obingwa in Abia, south eastern Nigeria. The studies were designed to: determine the effect of spent mushroom substrate (SMS) and NPK fertilizer on field performance of white and orange-fleshed sweetpotato in south eastern Nigeria; effect of interactions on orange-fleshed sweetpotato and maize productivity under different rates of spent mushroom waste and NPK fertilizer and effect of location and NPK fertilizer on three sweetpotato varieties raised in Triple S system. The three experiments were laid out as split-split plot in a randomized complete block design (RCBD) with three replications. Results showed that spent mushroom substrate significantly increased leaf area index, shoot biomass and storage root yield. Application of NPK increased leaf area index and top yield in both years and storage root yield in 2019. The white-fleshed TIS 87/0087 had higher root yield than Umuspo 3 in 2018, but in 2019, Umuspo 3 out yielded TIS87/0087. Three-way interactions were significant for shoot biomass in 2018 and for storage root yield in both years. The highest top yield (28.70-30.0t/ha) in 2018 was obtained from TIS 87/0087 at moderate rates of 2t/ha SMS and 300kg/ha NPK fertilizer. The highest storage root yield was obtained from TIS 87/0087 at 4t/ha spent mushroom substrate alone in 2018 and yield from Umuspo 3 at 4t/ha spent mushroom substrate only in 2019. Intercropping reduced significantly sweetpotato vine length, number of branches per plant, leaf area index, number of storage roots per plant, root weight per plant and storage roots yield in both cropping seasons. Intercropping also reduced maize leaf area index, 100-seed weight, seed yield and shelling percentage in 2019 relative to sole cropping. On the basis of mean land equivalent ratio, land equivalent coefficient and area time equivalent ratio, yield advantage accrued when both crops were intercropped under any fertilizer regime but highest economic returns was obtained from orange-fleshed sweetpotato sole cropping at 400kg/ha NPK + 2t spent mushroom substrate, followed by sole sweetpotato at 4t spent mushroom substrate only. Leaf area index in 2019 and shoot biomass, root weight and storage root yield in both cropping seasons (2019 and 2020) were significantly higher in Obingwa than in Umuahia location. There was a linear increase in number of branches, leaf area index, shoot biomass and storage root yield with increase in NPK fertilizer application up to 400kg/ha. White-fleshed TIS87/0087 and orange-fleshed Umuspo 1 varieties had higher values for number of branches, leaf area index, above ground biomass than orange-fleshed Umuspo 3, but the latter had significantly higher storage root yield, followed by Umuspo 1.
TABLE
OF CONTENTS
Title Page i
Declaration ii
Certification iii
Dedication iv
Acknowledgements v
Table of Contents vi
List of Tables ix
Abstract xiii
CHAPTER 1: INTRODUCTION 1
CHAPTER 2: LITERATURE REVIEW 5
2.1 Effect of Spent Mushroom Substrate (SMS)
on Crop Growth and Yield 5
2.2 Effect on NPK fertilizer on Crop Growth
and Yield 7
2.3 Effect of Variety on Crop Growth and
Yield 8
2.4 Effect of Intercropping on Crop Growth
and Yield 10
2.4.1 Types of intercropping 10
2.4.2 Sweetpotato and maize intercropping 11
2.5 Indices for Assessing Yield Advantage,
Productivity and Profitability 13
2.6 Interactions in Intercropping 15
2.7 The Benefit of Intercropping 17
2.7.1 Resource use efficiency in intercropping 17
2.7.2 Intercrop reduce incidence of pest and
disease 20
2.7.3 Intercropping reduce weeds 20
2.7.4 Intercropping regulates temperature 21
2.7.5 Intercropping modifies microclimate 21
2.7.7 Resources use efficiency in intercropping 22
2.8 Demerits of Intercropping 22
2.9 Effect of Triple S on Growth and Yield 22
2.10 Effect of Location on Crop Growth and Yield 24
CHAPTER 3 MATERIALS AND METHODS 26
3.1 Location of the Experiment 26
3.2 Planting Materials 26
3.3 Experiments 27
3.3.1 Experiment
1: Effect of spent mushroom substrate and NPK fertilizer
on
field performance of white and orange-fleshed sweetpotato varieties 27
3.3.1.1 Field preparation and soil sampling 27
3.3.1.2 Experimental design and treatments 28
3.3.1.3 Planting and field maintenance 29
3.3.1.4 Data collection 29
3.3.1.5 Statistical analysis 30
3.3.2 Experiment
2: Effect of interactions on orange-fleshed sweetpotato and
maize
productivity under different rates of spent mushroom waste and
NPK
fertilizer 31
3.3.2.1 Planting materials 31
3.3.2.2 Field preparation and soil sampling 31
3.3.2.3 Experimental design and treatments 31
3.3.2.4 Planting and field maintenance 32
3.3.2.5 Data collection 33
3.3.2.6 Statistical analysis 35
3.3.3 Experiment
3: Effect of location and NPK on three sweetpotato
varieties
raised in triple S system 36
3.3.3.1 Planting materials 36
3.3.3.2 Nursery operations of triple S system 36
3.3.3.3 Field preparation and soil sampling 36
3.3.3.4 Experimental design and treatments 37
3.3.3.5 Planting and field maintenance 37
3.3.3.6 Data collection 37
3.3.3.7
Harvesting 38
3.3.3.8
Statistical analysis 38
CHAPTER 4: RESULTS AND DISCUSSION 39
4.1 Soil and Meterological data and chemical
composition of SMS 39
4.2 Experiment
1: Effect of Spent Mushroom Substrate and NPK Fertilizer
on Field Performance of White and Orange-fleshed
Sweetpotato Varieties 45
4.2.1 Effect
on vegetative growth 45
4.2.2 Effect
on yield and yield components 56
4.2.3 Discussion 66
4.3 Experiment
2: Effect of Crop Interactions on Orange-fleshed Sweetpotato
and
Maize Productivity Under Different Rates of Spent Mushroom
Substrate
and NPK Fertilizer 69
4.3.1 Effect
on sweetpotato growth and yield 69
4.3.2 Effect
on maize growth and yield 80
4.3.3 Productivity
indices and economic returns 90
4.3.4 Discussion 96
4.4 Experiment
3: Effect of Location and NPK fertilizer on Three
Sweetpotato
Varieties Raised in Triple S System 100
4.4.1 Effect
on vegetative growth 100
4.4.2 Effect
on yield and yield components 107
4.4.3 Discussion 117
CHAPTER
5: CONCLUSION AND RECOMMENDATIONS 119
5.1 Conclusion
119
5.2 Recommendations 120
References 121
Appendices 140
LIST OF TABLES
TABLE PAGE
3.1: Description
of sweetpotato varieties used in the experiment 27
4.1: Soil
physical and chemical properties of Umuahia in 2018, 2019
and 2020 40
4.2: Soil
physical and chemical properties of Obingwa in 2019 and 2020 41
4.3: Meterological data of Umuahia in 2018,
2019 and 2020 42
4.4: Meteorological
data of Obingwa in 2019 and 2020 43
4.5: Chemical
properties of spent mushroom substrate used in the study 44
4.6: Effect of spent mushroom substrate on vine
length (cm) at different
sampling dates in 2018 and 2019 47
4.7: Effect of NPK on vine length (cm) at
different sampling dates in
2018 and 2019 48
4.8: Effect of variety on vine length (cm) at
different sampling dates in
2018 and 2019 49
4.9: Effect of spent mushroom substrate on
number of branches at different
sampling dates in 2018 and 2019 50
4.10: Effect of NPK on number of branches at
different sampling dates in
2018 and 2019 51
4.11: Effect of variety on number of branches at different sampling
periods in
2018
and 2019 52
4.12: Effect
of spent mushroom substrate on leaf area index of sweetpotato
at different
sampling periods in 2018 and 2019 53
4.13: Effect of NPK fertilizer on leaf area index
of sweetpotato at different
sampling periods in 2018 and 2019 54
4.14: Effect of sweetpotato variety on leaf area index at different
sampling periods
in
2018 and 2019 55
4.15: Effect
of spent mushroom substrate, NPK fertilizer and sweetpotato variety on fresh shoot biomass (t/ha) in 2018
and 2019 58
4.16: Effect
of interaction of mushroom substrate (M), NPK fertilizer (F)
and
sweetpotato variety (V) on shoot biomass
(t/ha) in 2018 and 2019 59
4.17: Effect
of spent mushroom substrate, NPK fertilizer and sweetpotato variety
on
number of storage roots/plant in 2018
and 2019 60
4.18: Effect
of interaction of spent mushroom substrate (M), NPK fertilizer (F)
and
variety (V) on number of storage roots/plant
in 2018 and 2019 61
4.19: Effect
of spent mushroom substrate, NPK fertilizer and sweetpotato
variety
on storage root weight/plant (kg) in 2018 and 2019 62
4.20: Effect
of interaction of spent mushroom substrate (M), NPK fertilizer
(F)
and sweetpotato variety (V) on storage root
weight/plant (kg) in
2018
and 2019 63
4.21: Effect
of spent mushroom substrate, NPK fertilizer and sweetpotato
variety
on storage root yield (t/ha) in 2018 and 2019 64
4.22: Effect
of interaction of spent mushroom
substrate, NPK fertilizer and sweetpotato
variety on storage root yield (t/ha) 65
4.23: Effect of cropping system on vine length of
sweetpotato (cm) at
different
sampling periods in 2019 and 2020 71
4.24: Effect fertilizer treatment on
sweetpotato vine length (cm) at
different
sampling
periods in 2019 and 2020 72
4.25: Effect of cropping system on number of
sweetpotato branches at
different
sampling periods in 2019 and 2020 73
4.26: Effect fertilizer treatment on number of
sweetpotato branches at
different
sampling periods in 2019 and 2020 74
4.27: Effect of cropping system on sweetpotato
leaf area index at different
sampling
periods in 2019 and 2020 75
4.28: Effect fertilizer treatment on leaf area
index of sweetpotato at different
sampling
periods in 2019 and 2020 76
4.29: Effect of cropping system and fertilizer
treatment on storage root weight
(kg) of orange-fleshed sweetpotato
(Umuspo 1 variety) in 2019 and 2020 77
4.30: Effect of cropping system and fertilizer
treatment on number of storage
roots
per/plant of orange-fleshed sweetpotato (Umuspo 1 variety) in
2019 and 2020 78
4.31: Effect of cropping system and fertilizer
treatment on storage root yield (t/ha)
of
orange- fleshed sweetpotato (Umuspo 1 variety) in 2019 and 2020 79
4.32: Effect of cropping system on maize plant
height at different sampling
periods at 4, 6, 8 and 10 WAP 82
4.33: Effect of fertilizer treatment on maize
plant height at different sampling
periods at 4, 6, 8 and 10 WAP 83
4.34: Effect of cropping system on maize leaf area
index at 4, 6, 8 and 10
WAP 84
4.35: Effect of fertilizer treatment on maize leaf
area index at 4, 6, 8 and 10
WAP. 85
4.36: Effect of cropping system and fertilizer
application on number of seeds/cob
of maize in 2019 and 2020 86
4.37: Effect of cropping system and fertilizer
application on 100-grain weight (g)
of
maize in 2019 and 2020 87
4.38: Effect of cropping system and fertilizer
application on seed yield (t/ha)
of
maize in 2019 and 2020 88
4.39: Effect of cropping system and fertilizer
application on shelling
percentage
(%) of maize in 2019 and 2020 89
4.40: Effect of intercropping and fertilizer
application on land equivalent
ratio (LER) 91
4.41: Effect of intercropping and fertilizer
application on land equivalent
coefficient (LEC) and Area time equivalent ratio (ATER). 92
4.42: Effect of cropping system and fertilizer
application on gross monetary
returns in 2019 93
4.43: Effect of cropping system and fertilizer
application on gross monetary
returns (#/ha) in 2020 94
4.44: Effect of cropping system and fertilizer
application on net returns (#/ha)
in 2019 and 2020 95
4.45: Main effect of location on number of
sweetpotato branches at different
Sampling periods 101
4.46: Main effect of NPK fertilizer on number
of sweetpotato branches at
different sampling periods 102
4.47: Main effect of sweetpotato variety on number
of branches at different
sampling periods 103
4.48: Main effect of location on leaf area index at different sampling
periods 104
4.49: Main effect of NPK fertilizer on leaf area
index of sweetpotato at
different sampling periods 105
4.50: Main effect of sweetpotato variety on leaf
area index at different
sampling Periods 106
4.51: Main effect of location, NPK fertilizer and
sweetpotato variety on shoot
biomass (t/ha) in 2019 and 2020 108
4.52: Effect
of interaction of location, NPK fertilizer and sweetpotato variety
on
shoot biomass (t/ha) in 2019 and 2020 109
4.53: Main effect of location, NPK fertilizer and
variety on number of
storage roots/plant in 2019 and 2020 110
4.54: Effect
of interaction of location, NPK fertilizer and sweetpotato variety on number of
storage roots/plant in 2019 and 2020 111
4.55: Main effect of location, NPK fertilizer and
sweetpotato variety on
storage
root weight (kg/ha) in 2019 and 2020 113
4.56: Effect
of interaction of location, NPK fertilizer and sweetpotato variety on number of storage root weight (kg) in
2019 and 2020 114
4.57: Main effect of location, NPK fertilizer and
sweetpotato variety on number
of storage root yield (t/ha) in 2019 and 2020 115
4.58: Effect
of interaction of location, NPK fertilizer and sweetpotato variety on storage root yield (t/ha) in 2019 and
2020 116
CHAPTER
1
INTRODUCTION
Sweetpotato
is a root crop which is reported to have originated in Central America and
introduced to Africa probably at the end of 19th Century (Dandago
and Gungula, 2011). The plant is now widely grown as an important staple food
crop in a number of African countries including Burundi, Rwanda, Uganda and
Nigeria among others (Awojobi, 2004). As food for humans, sweetpotato root
tuber is rich in carbohydrates and vitamin C. Orange-fleshed sweetpotato
varieties are particularly rich in beta-carotene, a precursor of vitamin A. Vitamin
A deficiency is a serious public health problem in many developing countries (Nwadinobi
et al., 2018) and the consumption of
small amounts of foods derived from orange-fleshed sweetpotato varieties could
eliminate or reduce vitamin A deficiencies in young children and pregnant and
lactating women. Sweetpotato roots can be consumed boiled, fried or roasted
while the leaves serve as a protein-rich leafy vegetable. The fresh root tubers
and leaves also serve as livestock feed.
Lack
of quality planting materials is often particularly acute at the on-set of the
rains (Namanda et al., 2013), after
the dry season has desiccated the foliage (Gibson, 2009). Unlike seed from
grain crops, for most vegetatively propagated crops like sweetpotato the
planting material is living (vines cuttings from live plants) and this makes
the maintenance of planting material from the root harvest to the next planting
season more challenging than in most crops, as living material (about 20% dry matter)
is also more subject to pathogens and infection compared with dry seeds with
80% dry matter (Mc Ewan et al., 2012).
The ever increasing temperature, shortage of irrigation water in the dry season
and competition for wetlands has posed a challenge for preservation of sweetpotato
vines over the dry season. SASHA (2017) recommended the triple S (storage in
sand and sprouting) method of sweetpotato planting materials conservation to
ensure their availability at the start of the rains. In addition to ensuring
early supply of vines, it also reduces incidence of sweetpotato weevil compared
to traditional methods of conserving planting material in dry areas. Farmers
using the triple S technology can therefore plant earlier and take full
advantage of the rains to obtain higher yields and benefit from early food
crop, before cereal crops are harvested. Ensuring that households have control
over their own seed source, by retaining healthy roots and sprouting them,
reduces the need to transport perishable and bulky planting materials over long
distances, at high cost and often with high level of wastage (CIP, 2015).
Maize
(Zea mays) is an important cereal crop that is grown widely as a carbohydrate
staple in many countries of the world (FAO, 2007). Several varieties exist
including white, yellow and red types (IITA, 2009). Maize is consumed directly
as food in various forms including boiled or roasted fresh ears, maize meal,
and porridge and serves as source of income to small and large scale farmers in
many developing countries (Ahmed and Yusuf, 2007). It also serves as livestock
feed. Furthermore, it serves as raw materials in the manufacture of starch,
oil, syrup, dextrose, gelatin, lactic acid and ethanol (Chinaka et al., 2017; Badu-Apraku et al., 2013).
Sweetpotato
and maize feature in the farming systems of south eastern Nigeria, where
intercropping is predominant. Intercropping offers farmers the opportunity to
engage in nature principles of crop diversity. Intercropping is one of the
cropping strategies that have been recognized to improve the food security
situation and incomes for farmers (Mahfuza et
al., 2012). It also helps to reduce weed populations, insect pests
infestation and risk of complete crop failure (Amede and Nigatu, 2001; Okpara,
2000; Islam et al., 2013).
Intercropping system becomes more productive and profitable when it is done
properly by selecting compatible crops (Begum et al., 2010), and by judicious application of chemical fertilizers
(Basak et al., 2008). Sweetpotato and
maize intercropping is compatible as they possess different photosynthetic
pathways, different growth habits and requirement of different growth resources
(Islam et al., 2007).
Whether
as monocrop or intercrop, sweetpotato and maize require adequate nutrient
supply to give high yields. Sweetpotato is more sensitive to nitrogen and
potassium deficiencies (Njoku et al.,
2001) while maize is very sensitive to macronutrient deficiencies (nitrogen,
phosphorus, potassium) including secondary nutrients such as sulphur, but less
sensitive to micronutrient deficiencies (Alejandro et al., 2006). The most common method of increasing crop
productivity is the use of inorganic fertilizer. Most small holder farmers,
however, lack the financial resources to purchase inorganic fertilizers, which
are not only expensive but sometimes hardly available. Consequently, there is a
need to look at the alternative means of addressing the problem of declining
soil fertility, such as the use of manure, crop residue or organic wastes
including spent mushroom substrate or combined use of inorganic fertilizer and
organic wastes (Materechera and Medupe, 2014). Alberto et al., (2017) recommended locally available materials as sources
of organic fertilizers including spent mushroom wastes as an alternative to
reduce the cost of farm input.
Mushroom cultivation is an ecofriendly activity as
mushroom compost or spent mushroom substrate is a slow release, organic plant
fertilizer made from organic materials such as hay, cereal straws, maize cobs,
saw dust on which mushroom grows (Bradley, 2004). Spent mushroom waste is a
good source of nutrients with high cation exchange capacity and slow
mineralization which retain its quality as an organic matter. It contains
1.9:0.4:2.4% NPK (Gupta et al., 2004)
and is valuable for the cultivation of root and tuber crops, cereals, fruit and
vegetable crops (Alberto et al., 2017).
Ahlawat et al (2006) reported that
spent mushroom waste improves soil texture, water holding capacity, nutrient
status and the physical aeration of soil, control disease of field crops and
enhances crop yield. Besides, the use of organic wastes or materials, Akpaninyang
et al., (2015) stressed the need for
combined application of organic and inorganic fertilizers to improve the
nutrient content of soil and increase the yield and quality of sweetpotato.
Ogoke et al., (2009) noted that even
though inorganic fertilizers are quick acting for soil enhancement to guarantee
soil health, they must be used within the context of soil fertility management
relative to soil type and other climatic conditions. The objectives of the present
investigations were to:
1. Determine
the effects of spent mushroom waste and NPK fertilizer on field performance of white and orange-fleshed sweetpotato in south
eastern Nigeria.
2. Examine
the effect of interactions on orange-fleshed sweetpotato and maize productivity
under different rates of spent mushroom waste and NPK fertilizer, and
3. Evaluate
the effect of location and NPK fertilizer on three sweetpotato varieties raised
in Triple S system.
Login To Comment