ABSTRACT
This study was carried out on the influence of fertilization type and methods of application on nutrient uptake and yield of maize. The growth and yield of maize cultivated with a complementary application of organic and inorganic fertilizers was assessed compared with sole organic and sole inorganic fertilizers between April and July 2017 and 2018 at Ibadan, Nigeria, in the degraded tropical rain forest zone. There was a no-fertilizer treatment as the control. The organic fertilizer was an equal mixture of composted domestic waste and stale cow dung, applied at 10 tonnes ha-1. Urea and Single super phosphate were applied as the inorganic fertilizer to supply 70 kg N and 13 kg P2O5 ha-1 respectively. The mixture of organic and inorganic fertilizer treatment consisted of half the rates used for sole organic and sole inorganic fertilizer treatments: 5 tonnes organic mixture was applied, with 35 kg N and 6.5 kg P2O5. Maize plant height at 8 weeks after planting was highest with inorganic fertilizer application while the leaf area was highest with organic fertilizer application. Stover yield and cob yields were also highest with inorganic fertilizer. Complementary application of organic and inorganic fertilizers however had similar plant heights; stover yield as well as cob yields with inorganic fertilizer. Nitrogen appeared chelated with organic fertilizer application. Plant ear – leaf Nitrogen was highest (1.68%) with inorganic fertilizer while the control plots had a Nitrogen content of 1.12% which was higher than 0.84% and 0.98% N from sole organic and a complementary application of organic and inorganic fertilizers, respectively. Plant P content was increased by 136% and 15% with organic and inorganic fertilizers, respectively, but was reduced by 15% with complementary application of organic and inorganic fertilizers. The K content was highest with inorganic fertilizer (1.91%). Complementary application of organic and inorganic fertilizers had a K content of 1.70% while the organic – fertilized leaves had 1.53%. Stover nutrient uptake was highest for N and K with inorganic fertilizer while the P was highest with organic fertilizer application. Cultivating maize with complementary organic and inorganic fertilizers gives a comparable cob yield as inorganic fertilizer and has nutrients higher than from sole organic fertilizer application.
CHAPTER ONE
INTRODUCTION
1.1 Background of the study
Fertilizers are materials of natural or synthetic origin which when applied to soils or to growing plants can promote their growth and yield. They supply one and more nutrients essential to the growth of plants. John L. Halvin et al (2014) in his book “Soil Fertility and Fertilizers” quotes from Shaler (1891), saying:
“When we perceive that civilization rests on the food giving capacities of the soil; when we perceive that all of the future advances of our kind depend upon the preservation and enhancement of its fertility, we owe to it.”
The need to use fertilizers has come into better appreciation as farmers realize its importance in improving the low nutrient status of tropical soils. As population increases, most of the cultivatable lands are taken up for uses other than crop production. Despite advances in the technique of agricultural production, significant proportion of the current world population is undernourished, primarily the underdeveloped nations (John L. Halvin et al., 2014). It is reported that our soils cannot support sustainable crop production over a meaningful time period (Adeoye et al., 2005). In the circumstance, the use of fertilizers offers a way out. Moses (1983) declared that the productivity of any given plant is a function of nutrient availability. The use of fertilizers is clearly very important because it enables the meeting of the nutritional and industrial needs of the teaming population.
Some factors hinder farmers from using fertilizers and they are: high product cost, farmer’s level of technology adoption, bulkiness of organic fertilizers, lack of information on the usage, etc. As earlier defined, fertilizers appear in different forms, which include liquid (as foliar), inorganic solids, bulky organic solids (manures).
The quest to know the best fertilizer to use either singly or in combination, to obtain better results in yield and in soil improvement has prompted this study of the effects of fertilizer type and combinations on the yield and uptake of selected nutrients by maize. Maize grows quickly and responds readily to nutrient supply effects. The bulkiness of organic manures also demands combinations of organic and inorganic types in order to reduce bulkiness while retaining the positive impacts of both types. Foliar spray fertilizers is coming more and more into vogue as they are claimed to promote high yields even in very small quantities.
The ever – increasing population of many countries of the world has necessitated the development of intensive agriculture technologies to sustain food yield. Soil fertility maintenance is essential in achieving and maintaining high crop yields over a period of time. Fertilizer application has usually been the major means of supplying plant nutrients. Use of mineral fertilizers has proven to be more convenient than the use of organic fertilizers that have traditionally been used since pre- industrial age. The impact of increased use of mineral fertilizers has been high but the resulting soil physical degradation, and increased soil acidity level and soil nutrient imbalance have drawn the attention of researchers back to the use of manures that are also known as organic fertilizers.
Several organic materials have been reported as suitable soil amendments for increasing crop production. The potential of cow dung, poultry droppings, refuse compost and farmyard manure as suitable soil amendments in the tropics has been reported. Application of organic materials as fertilizers provides growthregulating substances and improves the physical, chemical and microbial properties of the soil. Sole use of organic manures to sustain cropping has, however, been reported inadequate, as they are required in rather large quantities to meet crops’ nutrient requirements because of their relatively low nutrient content. Against the backdrop of this study, this study examines the influence of fertilization type and methods of application on nutrient uptake and yield of maize.
1.2 Statement of Problem
According to the Food and Agricultural Organization (FAO), there are about 795 million undernourished people in 2015 (FAO, 2015). To apprehend the situation, interests have been centralized on the exploitation, quantification and utilization of food plants, especially vegetables (Dini et al., 2005). In spite of the integrated use of various soil fertility amendment input aimed at alleviating nutrient deficiency and improving their availability in soil reserves, crop and nutrient yield still fall short of their potential because of inadequate nutrient and chemical inputs, inappropriate quality of the organic materials and insufficient combination (Palmer et al., 1997). Various studies has been done on how fertilizer use affect the yield on different plants but fewer research is carried on their effects on growth performance, nutrient and toxicological composition in leafy vegetables especially spinach which is commonly consumed in this part of world.
Furthermore, there are various fertilizers that have been shown to have effect on the yield of spinach in terms of growth. Therefore, it is necessary to investigate the exact effect of fertilization type and methods of application on nutrient uptake and yield of maize.
1.3 Objectives of the study
The main objective of this study is to examine the influence of fertilization type and methods of application on nutrient uptake and yield of maize.
Specifically, this study sort to:
- Compare the effects of fertilizer type and mode of application on nutrient uptake and yield of maize.
- Assess the performance of maize fertilized with complementary organic and inorganic fertilizers.
1.4 Justification
Maize is a cheap source of nutrients, biochemicals and phytochemicals which are responsible for normal physiological functions and also help in reducing the risk of chronic diseases. To enhance the optimal production of this nutrients and phytochemicals, appropriate use of fertilizers has to be employed. Many organic materials are produced around the home, or can be obtained at little or no cost from livestock operations, municipal green waste collection centers, and local landfills. Virtually any organic material can be used as a fertilizer; however, materials vary considerably in the concentration of plant nutrients they contain and the rate at which these nutrients are released for plant use. Therefore, some organic fertilizers are better for certain situations than others, and different materials need to be applied at different rates to supply the correct amount of plant nutrients (Koenig and Johnson, 1999).
A common misconception is that organic fertilizers are safer for plants and the environment than inorganic (chemical) products. Improper organic fertilizer application can also contribute to surface and ground water pollution, may induce a plant nutrient deficiency or toxicity. If properly used, both organic and inorganic fertilizers are safe for plants and the environment (Koenig and Johnson, 1999). Hence, it is necessary to evaluate the effect organic fertilizers will have on growth performance, nutrients and toxicological composition of maize.
