Format: MS-WORD Chapters: 1-5
Pages: 80+ Attributes: STANDARD RESEARCH
THE EFFECT OF FERTILIZER ON THE GROWTHS AND YIELDS OF MAIZE (ZEA MAYS) AND GROUNDNUT (ARACHIS HYPOGAEA L.) IN MIXTURE
possesses diverse significance in animal diet as well as regular feeding habits
on account of its nutritional composition and their health benefits from the
prehistoric era. Apart from that it also helps keeping away health related
disorder in human and at the same time ameliorates resistance against diseases
and provides enduring assistances. Groundnut is an important food, feed and
cash crop in Eastern Africa but in Kenya it has a yield gap of 2.5 t ha -1 and
this is attributed to low soil fertility, diseases, poor used quality and poor
1.1 THE ORIGIN AND HISTORY OF GROUNDNUT
Groundnut is native new world crop. Early explorers found it cultivated extensively in both Mesoamerica and South America. Remnant pericap (fruit hull) tissue recovered from archaeological sites in Peru date it’s purposeful agricultural use there at approximately 3900 – 3750 years before the present (YBP). No one is certain how much earlier domestification occurred but it probably first took place in the valleys of the Parana and Paraguay Rivers systems in the Granchaco area of South America. Today groundnut is an important oil, food and forage crop generally distributed in tropical, subtropical and warm temperate zone.
The exact origin of the principal cultigen, Arachis hypogaea L. remains a subject of scientific inquiry. Early Spanish, Portuguese, Dutch, German and other explorers found Indians cultivating the crop on many island in the Antilles, on the North East and East Coasts of Brazil, in all the warm regions of the Riodela, Platabauin (Paraguay, Bolivia, Northern Argentina, extreme South West, West Brazil), extensively in Peru and sparsely in Mexico.
1.2 INTRODUCTION TO THE MORPHOLOGY OF GROUNDNUT
Geocarpy, the development of fruit underground, characterizes all members of the genus Arachis (smartt and Stalker, 1982). After flowering and fertilization above ground, futher embryo development and fruit expansion are suspended while an intercalary meristem at the base of the ovary produces a gynophore (Jacobs, 1947; Brennana, 1969). The gynophore, carrying the ovary and it’s tap bends an elongates downwards to penetrate the soil.
Once the ovary is sufficiently buried, embryo development is resumed and fruit (pod) expansion occurs. Sugars, proteins and inorganic nutrients other than calcium (Ca) are translocated via the gynophore to the developing pod. Calcium is poorly translocated via the phloem of the gynophore and must be absorbed by the developing pod (Skelton and Shear, 1971). Cox, Adams and Tucker (1982) concluded that Ca decency is the most common nutrient limiting groundnut yield on acid, coarse-textured soils in the USA. Many Arachis species produce a secondary gynophore between seed compartments (Rao and Murty, 1994) resulting in a lomentiform pod (Smartt, 1994). A strong constriction (Rao and Murty, 1985) may develop between seed compartment in groundnut (A. hypogaea‘L.), but is not usually evident incultivated forms (Gregory, Krapovikav and Gregory, 1980; Smartt and Stalker, 1982; Smartt, 1994).
There has been selection against lines with present address: Department of Biological Sciences, University of Zimbabwe, P.O. Box MP 167, Mount Pleasant, Harare, Zimbabwe for correspondence constricted ponds and secondary gynophores because of poor quality and difficulty in harvesting and processing. Many other characteristics differ among and within the three cultivated groundnut types, Spanish (spp. Fastigiata Var. aulgaris). Valencia (Spp. Fastigiata Var. Fastigiata) and Virginia (spp. Hypogaea Var. hypogaea) (Bonting et al., 1985). Initial work by Waldron (1919) led to the conclusion that the production of healthy groundnut pods and seeds requires darkness, moisture and mechanical stimulus normally provided by contact with the soil. Improved embryo development in tap water that had not been boiled over that which had been boiled led (Shibuya, 1935) to reduce that Oxygen is necessary for pod development. They found that the basal used compartment developed when pods were grown in mist culture with no mechanical stimulus, but a secondary gynophore separated the basal and the undeveloped, distal part of the pod.
The apparent requirement for a mechanical stimulus for normal pod development has precluded studies on the uptake and assimilation of nutrient by groundnut pods in solution culture. However, Zharare et al, (1993) recently developed a technique which allowed the development of healthy pods of a Spanish cultivar, TMV-2, in solution culture with no mechanical stimulus other than that provided by aeration. This recent advance allows for the first time, the chemical environment of the pod to be carefully monitored and controlled. This paper reports the effects of aeration and Ca concentration in solution on pod development in seven groundnut lines.
1.3 MORPHOLOGY OF GROUNDNUT
Basal ovule (Gregory et al., 1973) is unique to the genus. The expansion of the intercalary meristem results in a lomentitorm carpel of one to five segments, each containing a single seed with two very large cotyledons and a straight embryo.
A general description of Arachis is as follows (after Bentham and Hook, 18:62): Seeds with thick and fleshy cotyledons; short radicle growing into well-developed taproots; plants low suberect herbs, often prostrate and even creeping; leaves abruptly bipinnate, tetrafoliolate leaves with two pairs of opposite leaflets, rarely trifoliolate, exstipellate, stipules adnate to the petiole at the base. Flowers crowded in simple or compound monopodium, look like dense auxiliary species, sessile in the leaf axil, or very shortly pedicellate. Calyx lobes five, often dentate, calyx tube filiform, lobes membranaceous, the four upper ones connate, the lower one slender, separate petals and stamens inserted at the apex of the tube, standard Oblong, obovate to suborbi-culus, wings oblong, free keel incurved, prostrate. All segments connate to form a closed stamina tube, stamens 10, usually one absent, another alternative, elongate, sub basic fixed, the alternative ones versatile. Ovary subsessile towards the base of the calyx tube, usually aerial, occasionally subterranean, two-to-three-ovuled.
When the flower withers and falls away, the ovary shows a stalk, which elongates and becomes reflexed and rigid and the ovary is continuous with the same, acute at the apex; style long, filiform with a minute terminal stigma; the pod ripens inside the soil, oblong, stick, indehiscent, subtorulase, articulate or non-articulate. Seeds one to three, irregularly ovoid, rich in oil and protein
1.4 ECOLOGY OF GROUNDNUT
Groundnut requires abundant sunshine and warmth of normal development, but does not appear to be especially sensitive to day length, though it generally produces more flower under long day conditions (Stalker, 1997). Temperature significantly influences the rate of development and growth of groundnut the optimum range for vegetative and reproductive growth being between 25 and 300c (Cox, 1979; Lecong & Ongi, 1983). Groundnut grows in regions with an average annual rainfall of 580-1200 mm, thrives best when more than 500 mm of rain is evenly distributed during the growing season (SellSchop, 1967). Moisture stress during reproductive development causes embryo abortion, reduces seed development by restricting Calcium uptake by the pods, and increase eflafoxin contamination of the seeds (Stalker, 1971).
Groundut is grown mostly on light-textured souls ranging from coarse and fine sands to sandy clay loams with moderately low amounts of organic matter (1 – 2%) and good drainage (Henning et al., 1982). The well-drained soils provide good aeration for the roots and nitrifying bacteria. Groundnut does not grow well in soils with a high water retention capacity (Stalker, 1997), and grows best in slightly, acidic soils with optimum PH ranging 5.5 to 6.2 (Gibbons, 1980). Groundnut requires considerable amount of nutrients for high yields, however, responses to applied fertilizers have been observed to be very erratic, justifying the name of the “unpredictable legume”. It has often been accepted that groundnut has the ability to utilize soil nutrients that are relatively unavailable to their crops, and can therefore make good use of residual fertility. An effective fertilization programme should take no cognizance the level of nutrient removal.
The most critical element in the production of groundnuts is Calcium, and in many regions of the worlds, it is a major limiting factor to groundnut production. The developing pods require adequate Ca in the surrounding soil for proper pod development and production of high quality seed (Cox et al., 1982; Gascho & Davis, 1994). Because root – absorbed Ca is not translocated to the developing pods after the groundnut peg has entered the soil (Brady, 1947), the Ca required for pod development must be absorbed directly from the soil solution, thereby necessitating high Ca levels in the podding environment soil. Ca level in the range 6000 to 800 mg Kg+ in the fruiting zone (0 – 10cm) are considered adequate for the production of good quality ground kernels (Kvien et al., 1988; Sumner et al., 1988).
Calcium deficiency result in lower yield, darkened plumber in the seed empty pods (pops), reduced percentage of sound nature kernels and some times plan that stay green and continue to produce flowers and pegs, many of which may be infertile. To avoid Ca deficiency in the pod zone a soluble source of Ca like gypsum can be applied always respond to such Ca supplements (Walker, 1975). In acid soil, lime in corporation into the pod zone before planting can correct soil acidity and simultaneously supply adequate Ca for maximum yield of small-seeded cultivars (Gascho & Kidder, 1993).
Magnesium deficiency rarely limits plant growth, however, its necessity for groundnut stems from its roles as a carrier of phosphorus in oil formation, and its effect on seed viability (Smith et al., 1994). Little response of Mg application has been recorded for groundnut expect on excessively drained soils where cations are easily leached, and in acid with very low Mg levels (Gascho & Davis 1994; Smith et al., 1994). When Mg deficiency occur in acid sandy soils, the deficiency can be corrected by applying dolomitic limestone, which will correct the acidity and supply both Mg and Ca (Sanchez, 1976; Foster, 1981).
Nitrogen, Phosphorus and Potassium
When inoculated with effective strains of Rhizobia, the groundnut is independent of Nitrogenous fertilizers because enough N is fixed through symbolic relations with Bradyrhizobium Spp. It has been shown that uptake of flowering and pod formation. During the N from leaves to the developing fruit, and this some time result in appearance of N defiency symptoms. In most growing areas of the world applications of N to groundnut in order to avoid deficiency is common, and to responses to N fertilization have been observed on deep sandy soils (Gascho, 1992). Groundnut is often grown p deficient soils in many areas of the world (Cox et al., 1982; Survanvesh & Morrill, 1986). The P deficiency can be easily corrected by application of P: fertilizers, since groundnut is normally grown on sandy soils with low amount of clay and P fixation is generally not a problem. Also, P requirement and removal by groundnut is low, and very little P leaches (Gascho & Davis, 1994). Although groundnut is largely unresponsive to P application, large responses have been observed in soils with high P fixation, particularly under low fertility conditions.
Generally, it is believed that groundnut requires very little K for its growth and reproduction. The crop removes small amount of Potassium and will only respond to K application when the soil K levels are very low reported in literature, the consensus is that there is no advantage in applying K fertilizer directly to the ground crop, consequently, it is usually grown on residual fertility, following a well-fertilized crop (Cox et al., 1982). This is because groundnut root are efficient in obtaining K from low available levels in the soil. Because of this efficiency in utilization of soil K from soils that are low in available K, groundnut response to K fertilizers is rare (Werss, 1983).
Availability of micronutrient in soils is governed by soil PH, cation and anion exchange capacity, nutrient interactions, soil physical and chemical properties.
Groundnut requires the seven micronutrients known to be essential for plants; boron (B), Chlorine (Cl), Copper (Cu), Iron (Fe), Manganese (Mn), Molybdenum (Mo) and Zinc (Zn). The micronutrient most often limiting for groundnut production is B, because of its role in kernel quality and flavour. Boron deficiency results in hollow-heart in groundnut kernels. Zinc and Mn deficiencies can be expected in soils with high lime content, especially when high levels of P have been applied. At low soil PH the availability of Mn and Zn may increase to toxic levels, and liming very acidic soils to PH Ss decrease the solubility and uptake of Mn sufficiently to eliminate the toxicity.
1.5 INSECTS PESTS OF GROUNDNUT, NATURE OF DAMAGE AND SUCCESSION WITH THE CROP STAGES
Groundnut (Arachis hypogaea’L) is an important oil seed crop in Bangladesh on the basis of both acreage and annual production (Biswas et al., 2000; Mondal and Wahhab, 2001). It’s cultivation covered about 87,000 hectares and produced about 1,25,000 metric tons of seeds during 2011-2012 (Krishi Diary, 2013). On of the major constraints to the successful groundnut production in Bangladesh is the damage caused by insect and mite pests. Studies reveal that 15-20 percent of the total oilseed production is lost directly or indirectly by the attack of insect and mite pests every year (Biswas and Das, 2011).
In developing eco-friendly management strategies information on the pest complex, their status, incidence, and damage severity are of importance. The insect pest of groundnut in Bangladesh was recorded by several scientists (Alam, 1976; Hobbs, 1976; Kaul and Das, 1986; Begum, 1995; Biswas et al., 2009) which are far from complete. No information on the building up of the pests in relation to other pests, crop growth stages or to different parameters of climate is available.
A thorough understanding of these aspects of pest management can help in forecasting any outbreak of the pests and to develop an integrated pest management in groundnut (Yayanthi et al., 1993). In order to develop economically feasible, ecologically sound, and socially acceptable pest management strategies, detailed information of a pest complex, the status and the sequence of appearance of the pest during the crop period, the losses and type of damages of the crop are of great importance (Bijjur and Verma, 1995). In Bangladesh, check list of insect pests of groundnut and their damage severity in this country are scanty.
Therefore, the present study was undertaken to determine the insect pest complex of groundnut, status of the pests, the nature of damages, and the time of appearance of the pests in relation to the phenology of the crop. Materials and method of the experiment was conducted in the field and laboratory of the Oilseed Research Centre, (ORC), Bangladesh.
1.6 PESTS/DISEASES OF GROUNDNUT
The following are some of the diseases that affect groundnut:
1. Collarrot (Aspergillusniger): it is prevalent in almost all groundnut-growing states and the losses in terms of mortality of plants ranges from 28 to 50%. It is particularly serious in the sandy loam and medium black soil of the Punjab, Tamil Nadu, Uttar Pradesh, Rasasthan and Haryana. The fungus present in the soil or adherent on seed surface germinates and attacks the seeds before its germination and causes pre-emergence rotting of seeds. It also causes rotting hypocotyls, post-emergence seedling blight, rapid wilting of entire plant or its branches which are characteristic diagnostic symptoms. Collar region of the affected plants 448 disease of pulses, oilseeds and field crops becomes shredded and becomes dark brown covered by mycelia growth and spores. Soil borne inoculum is the primary source of infection. The pathogen can tolerate low soil moisture (13-16%). The fungus develops best at temperature between 31 and 35%.
2. Stem Rot (Sclerotiumrolfsli): In India, stem rot occurs in all groundnut growing states, particularly more severe in Gujarat, Maharashta, Madhya Pradesh, Odisha and Tamil Nadu, where approximately over 50,000 ha of groundnut field sere infected with S.rofsii. Latur, Raichur, Dharwad, Junagadh and Hanumangarh have been identified as ‘hot spots’ for the diseases. About 29% or more yield loss due to this disease has been reported from India (Chohan, 1974). Mayee and Datar (1988) have reported yield losses of over 25% in Maharashtra. The indirect losses such as reduction in dry weight and oil content are also reported. The initial symptoms are partial or complete wilting of the stem or branches that are in content with the infected soil.
White mycelia growths wit brown colour sclerotia are visible on the infected plant parts. The leaves turn brown and show wilting but remain attached to the plant.
Infection of Pegs, pod rot and leaf blight are another symptoms of stem rot infected plants. The pathogen has a wide host range. S. rolfsii can colonize either living plant tissues or plant debris. Deeply buried sclerotia survive a year or less while those near soil surface remain viable for many years. Defoliated leaves can also serve as a bridge to facilitate plant to plant spread. The pathogen spreads through infected soil, wind splash drain and sclerotia.
Types of crop residue particularly influence the sclerota (germination, mycelia growth and infection by S. rolfsii in groundnut (kumar et al., 2010; 2011). Soil moisture to the extent of 40 to 5-% of water holding capacity and temperature between 29% - 320c during day and 250c during nights favours the pathogen infection and disease development.
3. Dry Root Rot (macro phominaphesolina): Also known as dry wilt or charcoal rot is Sporalic in occurrence and is particularly serious in Rajasthan, Uttar Pradesh, Tamil Nadu, Andhra Pradesh and Maharashtra. The pathogen causes serve seedling mortality resulting in patchy crop stand and thus reduces the yield.
The symptoms appear as water soaked necrotic lesion that girdles the stem just above the ground level and wilting follows. The tap root turns black and later rots and shreds. Kernels turn black with abundant sclerotic on inner wall of the smell and surface of the testa. The pathogen has wide host range. The pathogen is a facultative saprophyte and a soil dweller. Infected soil, plant debris and pods serve as sources of inoculums. The optimum temperature for seedling infection is 29 to 35oC and to pods invasion is between 26 and 32oC. The sclerotic are disseminated via plant debris, soil, infected pods, shell and kernel.
4. Afla Root/Yellow Mold (Aspergillusflauus): It is prevalent in almost all groundnut-growing states. The yellow mold fungus, A. flavus is commonly found in the seed of both rotten and apparently healthy pods of groundnut. It first appears on cotyledons after the emergence of seedlings. Infected plants generally become stunted leaf lamina is drastically reduced with a pointed tip. Vein clearing and chlorosis of the leaflets is also visible. Infected seedlings lack a secondary roots system, a condition known as “afla root”. Such plants do not produce flowers and hence become unproductive. Yellow green Aspergillus colonies develop on over mature and damaged seeds and pods.
Soil born inoculum is the primary source of infection. The pathogen can tolerate low soil moisture and the fungus develops best at temperature between 25 and 35oC.
1.7 ECONOMIC IMPORTANCE OF GROUNDNUT
The peanuts (seeds) are used for roasting or salting and for the preparation of peanut butter. Peanuts are very nutritious food. One 1b of peanuts yields 2700 cal.
The filtered refined oil is used for cooking and in making margarine. Peanut oil is important food oil. The oil cake is used as podeler. The protein in peanuts is used in the manufacture of ardil, a syutheticfibre. The vegetable ghee is made from the peanut oil after hydrogenation.
The kernels are also used in various foods and confectionery. They are ground and made into peanut butter. Peanut flour is prepared by grinding the finest grades of peanut cake; it is used for supplementing the white flour. Cake is used as feed for cattle and others farm animals; also used as manure. Cake has high nutritive value. Seed coats are mixed with groundnut husk and the product is called groundnut bran.
Some commercial products are groundnut milk, peanut ice-cream and peanut massage oil for infantile paralysis are used as filter for fertilizers or ground into meal for insulation blocks, elor sweeping components bedding the stables etc. Peanut oil also finds some use as a lubricant and blends with mineral oil have been developed.
1.8 INTRODUCTION OF MAIZE
Although maize (zea mays) is a vigorous and tall growing plants, it is susceptible to competition from weeds, with commonly reported yield losses greater than 30% (Chikoy&Ekeleme, 2003). Enhanced crop competitiveness can be achieved rather by specific breeding programme or through changing crop husbandry, such as adjusting the time of planting, inter and intra-row hoeing, growing of crop cultivars with vigorous growth and fertilizer rate and placement. The expect of all these factors depends greatly on crop species, type and level of weed infestation and environmental conditions. Identifying factors that could affect crop competitive ability independently or synergistically with known factors over a wide range of situations is therefore important to enhance crop competitive ability.
Maize is very sensitive to weed competition from early stages of growth. It is generally assumed that weeds present within maize row are harmful for its growth and development, since weeds compete with crop for nutrients, water and space. It has also been demonstrated that at early stages of crop weed competition, weeds located nearer to or in between crop rows are most critical. Competition between crops and weeds for nutrients depends largely on total amount and type of nutrient present and their timely availability. Management practices, such as fertilizer replacement that can alter nutrient availability, can greatly affect weed infestation and crop competitive ability. However, very little is known about the effects of fertilizer placement with particular reference to time of removal in maize. The present study has thus been conducted to determine the effect of inter and intra-row weed-crop competition durations on growth and yield of maize under different fertilizer application methods.
1.9 THE ORIGIN OF MAIZE
Maize (zea mays) also known as corn, is a cereal grain first domesticated by indigenous people in Southern Mexico about 10, 000 years ago. The leafy stalk of the plant produces pollen in florescence and separate ovuliferous inflorescences called ears that yield kernels or seeds, which are fruits. Maize has become a staple food in many parts of the world, with the total production of maize surpassing that of wheat or rice. However, little of this maize is consumed directly by humans: Most is used for corn ethanol, animal feed and other maize products such as corn starch and corn syrupy. The six major types of maize are: dent corn, flint corn, pod corn, popcorn, flour corn and sweet corn.
The origin of the maize ear has been considered one of the greatest mysteries in both crop domestication and plant evolution. Although a wealth of botanical and genetic information has identified the wild Mexican grass teosinte (zea mays ssp. Parviglumis) as the direct progenitor of maize the profound differences in the structure of the maize and teosinte female inflorescences (ears) have challenged the formulation of a compelling model for the developmental and genetic steps involved in this evolutionary transition. At the head of the problem is the fact that teosinte kernel are tightly encased in structures called Copulate fruit cases, whereas maize kernels are borne uncovered on the surface of the ear. The strength with which the fruit case envelops the teosinte kernel and the stony nature of this casing far exceed the relatively flimsy and loosing bound chaff that surround the kernels of the ancestors of the other domesticated cereals. Indeed, the stony fruit case of teosinte had been considered such an obstacle to the use of teosinte as a grain that teosinte was dismissed by some as a possible progenitor of maize. It was argued that the genetic steps to free the grain from this casing and thereby convert teosinte into a useful crop were too complex to have arisen under domestication.
1.10 INTRODUCTION OF MORPHOLOGY OF MAIZE
Optimizing high plant density may increase the potential for achieving greater crop yield since there are more plants single harvesting unit (eg. Per hectare). Nevertheless, harvest of crop biomass and grain yield can decline if plant density exceeds certain thresholds though modern hybrids have an improved capacity to withstand high plant density. Accordingly, the optimization of plant density is of great interest in the maximization of maize productivity for different hybrids that continue to be developed in agricultural practice. Crop growth and yield in maize depend on incident radiation intercepted by the canopy and light composition of interrupted radiation such as Red (R): Far Red (FR). Both intercepted light quantity and its quality in the canopy are largely determined by canopy structure, which is influenced by plant population density. Consequently, much attention had been directed to how the maize canopy responds to increased plant density.
The effects of increased plant density on maize morphological development have been examined extensively at the canopy level including plant height, leaf area per plant and leaf area index. It should be noted that the whole plant level effects are realized through organ responses that may vary with positions in different types of organs. For example, the effects of plant density on leaf differs in leaf width and length, the former being consistently reduced in both lower and upper phytomers whereas the latter being increased in lower phytomers and reduced in upper phytomers. Hence, it is necessary to focus on organ morphological response to increased plant density for better understanding of the crop genetic basis that may be neglected at the whole canopy level with respect to intraspecific competition.
1.11 MORPHOLOGY OF MAIZE
Maize green largely consists of endosperm that is rich in starch (71%). Both the embryo and endosperm contain proteins but the germ proteins are superior in quality as well as quality. Zeins are a class of alcohol soluble proteins that are specific to endosperm of maize (Prassanaetal., 2002) and are not detected in any other plant part. The maize endosperm consists of two elistrict regions having different physical properties. The aleurone layer is the outer most layer rich in hydrolytic enzymes secreted by specialized cells. Within the aleurone layer the starch rich endosperm having vitreous and starchy regions. The zein proteins found in vitreous region form insoluble acreetrons called protein bodies in the lumen of rough endoplasmic reticulum and towards maturation are density packed between starch grains (Gibbon and Larkins, 20055). These zeins consist of albumins, globulins, glutamines and protamine’s and constitute about 50-60% of maize proteins. The protamines are rich in praline and amide nitrogen derived from glutamine. All protamines are alcohol soluble (Snehryand Halford, 2002). The protamine’s of maize grains are called zeins and consist of one major class (aozeins) and three minor classes (B &S). The zein fraction a is rich in Cysteine while B and fractions are rich in methionine. These four type a, B and S constitutes about 50-70% of maize endosperm and are essentially rich in glutamine, leonine and praline and poor in lysine and tryptophan. Other proteins such as globulins (3%), glutelins (34%) and albumins (3%) are collectively called non-zeins. The zein fraction in normal maize normally contains higher proportion of leonine (18.7%), phenylalanine (5.2%), isoleucine (3.8%), valine (3.6%) and tyrosine (3.5%), but smaller amounts of other.1.12 ECOLOGY OF MAIZE
Of all environment factors, solar radiation is the second most important in maize production. It is the sources of energy used by pants for photosynthesis.
The amount of solar energy received at the earth’s surface each day depends upon the intensity of the radiation, which varies with the sun’s elevation and the amount of dust, water vapor and cloud cover, and upon the length of the day which varies with latitude and with the seasons of the year.
Although the amount of solar energy received by crops is beyond the control of farmers (except of course that they can provide shade) the efficiency with which crop utilize it to produce dry matter, and especially the proportion of this dry matter which goes into economic yield, varies between the cultivars and between species, and maybe influenced by aspects of crop husbandry such as sowing date, plant density and level of fertility.
The maize crop requires warmth throughout it active life and is sensitive to frost at all stage. Its response to temperature between places, and seasonal variation at any place, tend to follow variation in isolation, the tropical environment is hot throughout, the year. Indeed, a major distinction between the environment for crop growth in high latitude or temperature regions and the tropics is that the duration of the growing season is limited by winter. Cold in much of the temperature agriculture, but by winter drought (often accompanied by very hot days) in much of the tropics. In the lowland equation tropics there is little seasonal or diurnal (day/night) variation from a mean temperature of around 24-27oc but in the regions of summer rainfall to the North and South of the equation both seasonal and diurnal variation of temperature are relatively large. In these areas, the collest temperature of 15oc or less occurs at night in the early mid-dry season, and the hottest (40oc or hotter occurs soon after mid-day in the weeks before rains begins, when the sun is high and there is little or no cloud cover.
Tropical rainfall depends largely upon global pressure and wind systems. A distinct belt of low atmospheric pressure called the “Doldrums” occurs around or slightly to the North of the equator in the Northern hemisphere.
Though they are deflected by the earth’s rotation, winds blow towards this zone from area of semi permanent high atmospheric centred around latitude 20o-30oN and S of the equator where the world’s great deserts occurs.
Effect of Weather on Certain Periods of Maize Plant Growth
i. Before planting: The influence of weather on the maize plant starts even before planting. Conditions before planting are especially important in determining soil moisture reserves. The lower the soil moisture reserve, the greater is the crop-season rainfall requirement.
ii. Planting of emergence: The period from planting to emergence depends on soil temperature, soil moisture, soil aeration, and seed vigour. Before germination the seed absorbs water and swells with warmer temperatures less water has to be absorbed so that germination will start earlier and proceed faster at higher temperature.
iii. Early vegetative growth from emergence to flower differentiation: During the early part of its life, the maize plant requires a limited amount of moisture for the small growth that takes place. Young maize plants are relatively resistant to cold weathers with an air temperature near 1oc, generally killing exposed above ground parts. Maize growth during vegetative stage has been found to be related to both air temperature and rainfalls. Late vegetative growth from the beginning of rapid stem elongation to tussling.
In the late vegetative stages, the relationships between weather and yield have been more marked and significant. Maize plants grow very rapidly at this stage and moisture stress during this period will cause yield reduction.
iv. Grain production from fertilization to physiological maturity of the grain:
During the ear-filling stage, significant reduction in yield can occur from moisture stress. In a dry year, with low-soil moisture reserves, increased rainfall during the ear-filling stage will increase maize yields, but in a wet year, too much rain at this stage may create some problems for harvesting. This may be particularly important on the more poorly drained soil in the water areas.
v. Maturation or Drying of the Grains: After physiological maturity, the grain must dry down to a harvestable moist level. The rate of drying is affected by the weather and cultivar characteristics.
Maize is an excellent example of crop adaptability to soil conditions. It is grown on a wide variety of soil and before looking at specific soil requirements for maize production it is essential to look at these physical, chemical and biological properties of soil that affect of fertility of the soil.
Soil consistence refers to the forces of cohesion and Adhesion exhibited by the soil i.e. It is the degree of plasticity and streakiness of the soil. Soil consistence is determined by the type of clay in the soil. Do not confuse soil consistence with soil texture. Soil texture refers to the relative amounts of sand, silt and clay in the soil, while Soil Consistence refers to the type of clay in the soil.
Soil colour has little actual effect on the soil, however there are many things which we can tell about a soil by observing it colour:
i. Soil colour and organic matter: Soils high in organic matter are black or dark coloured.
ii. Soil colour as related to soil temperature: Dark-coloured soils absorb more heat, thus they warm up more quickly and tend to exhibit higher soil temperature.
iii. Soil colour and parent materials: Soils formed from manic rocks will usually be darker in colour and higher in nutrients than soil formed from felsic parent materials.
iv. Soil colour and drainage: Many soils have enough iron in them to turn red if they are oxidized (rusted). Soil which are well drained are red and yellow in colour due to oxidized iron, while poorly drained soils have blue and grey colour due to reduced iron.
Fertilizers and Manures
Nutrition of the maize plant: The need for adequate and balance nutrition of maize is important. Because of its fast growing nature, the maize plant has a relatively high demand for nutrients, particularly N, P, and K, for obtaining high yields. A maize crop producing 5 to 6 x/ha of grain will remove about 100-150 kg N, 40-60 kg P2 O5 and 100-150kg K2O per hectare (Prasead, 1978). Most cultivated soils cannot supply more than 20-25 percent of the NPK requirement, and thus adequate NPK is necessary if high yields are to be maintained.
Nitrogen: In the maize crop, nitrogen is taken up at a low rate during development but the rate of uptake picks up rapidly by tasseling stage when about 4kg of nitrogen is taken up per hectare per day. The rate of uptake, however, decreases after grain formation. By the tasseling stage, maize plants have accumulated over 40 percent of their total requirement during the season. The percentages of nitrogen in the plant decreases with the age of the crop and at harvest about two thirds of the total nitrogen should be in the grain.
Nitrogen is taken up in large amount by the maize plants, and therefore the dominant form in which it is taken has a marked influence on the cation; anion balance in the plants. When NH=4 –N is absorbed, the uptake of other cations such as Ca, Mg and K will decrease. On the contrary, the uptake of anions and in particular P, will be favoured. The opposite occurs with the NO3N uptake. The relative proportion of N taken up by the maize plants in the form of NH4 –H and NO3 –N, depends on the age of the plant.
Phosphorus: Although the phosphorus requirement is only 1/10 of the nitrogen and 1//5th of the potassium, adequate supply of easily available P is essential, particularly during early stages of growth when the limited root system is not yet capable of drawing sufficiently on the P reserves in the soil.
Phosphorus is taken up by maize continuously from the seedlings stage to maturity. The concentration in the plant should be much higher during the seedling stage but the capacity of the roots to obtain phosphorus is then low and any deficiency of phosphorus is usually seen before the crop is 60-75cm tall. Phosphorus uptaken is maximum during the third and sixth weeks of growth. At maturity, about 75 percent of the total phosphorus is present in the grain. Plants deficient in phosphorus have a purple colouration on the lower leaves. The purple color also observed when the temperature is low or when the soil is saline.
Potassium: Potassium is generally indispensable for all living organisms, and its concentration in the plant tissue exceeds that of any other cation. Though K is not a constituent of important plant components, it however plays an important role in physiological processes of the plant, and thereby directly determines the rate of growth and yields. Photosynthesis maybe decreased and respiration increased under conditions of K deficiency. Potassium is important for increasing photosynthesis under conditions of low light intensity and also to make efficient use of light at higher intensives, which is of great significance with high plant population densities so common for modern maize production.
The rate of accumulation of potassium during the first 30 days of growth exceeds that of nitrogen and phosphorus (Arnon, 1975). During a period of 30 days beginning about two weeks before tasseling, the daily rate of uptake has been calculated by (Sere, 1955) to be 4 Kg 420/ha and according to (Chandler, 1960) may reach 7.3 Kg/ha K uptake follows a much different pattern from that of dry matter accumulation. Prior to silking, K uptake is faster than ddry matter accumulation and by silking almost 90 percent of the K has accumulated.
Fertilization of Maize: Adequate and balanced fertilization is essential in order to obtain high yields. It is roughly estimated, that for providing each 100 kg grain, 2.43 kg N, 0.53 kg P, 1.8 kg K are required. In fertilizing maize, information on the nutrient supplying power of the soil is essential before one can figure out how much mineral fertilizer should be added. The fertilizer required can be estimated from the net needed for certain yield level less the amounts of nutrients that can be supplied by the soil; taking into account certain adjustment, such as; nutrient losses and nutrient retention in the soil.
ANATOMY, MORPHOLOGY AND REPRODUCTION OF MAIZE
Most corn plants have a single tem, called a stalk, which grows vertically upward from the ground. The height of the stalk depends both on the variety of the corn and the environment in which a corn plant is grown. As the stalk grows, leaves emerge. A typical corn plant grown by a farmer in the Central United State will have a stalk that is 7 to 10 feet tall and has 16 to 22 leaves. The lower parts of each leaf wraps around the stalk and attached to the stalk at a juncture called a node. Typically the lowest four nodes are below ground. Roots develop from each node and these are known as brace roots. Some varieties of corn which grow outward from near the base of the main stalk.
Every corn plant has both male and female parts. The male part which is known as the tassel, emerge from the top of the plant after all the leaves have emerged. The tassel usually consists of several branches, along which many small male flowers are situated; each male flower releases a large number of pollen grains, each of which contains the male sex cell.
The female floral organ is called an ear. The ear develops at the tip of a shank, which is a small, stalk-line structure that grows out from a leaf node located approximately midway between the ground and the tassel. Occasionally a plant will produce an ear at several consecutive nodes, but the one that is located upper most on the stalk becomes the largest ear. The immature ear consists of cob, eggs that develop into kernels after pollination, and silks. The cob is a cylindrical structure upon which kernel development occurs. The kernels are arranged on the cob in pairs of rows. From each egg, a hair-like structure called a silk grows and eventually emerges from the tip of the husk, which is a group of leaves attached to the shank that encloses the entire ear. Pollination occurs when pollen falls on the exposed silk. Following pollination, a male sex cell grows down each silk to a single egg and fertilization (the union of the male and female sex cells) occurs. The fertilized egg develops into a kernel and inside each kernel is a single embryo (a new plant). A vigorous corn plant may have 500 to 1000 kernels on a single ear.
1.14 PSYCHOLOGICAL PESTS/DISEASES OF MAIZE
1. Nitrogen Deficiency: The typical symptom of nitrogen deficiency is the plant turns pale green; a 'V’ shaped yellow coloration on leaves. This pattern starts from leaf end to leaf collar. The symptoms begin from lower to upper leaves.
2. Phosphorous Deficiency: The deficient plants are dark green and lower leaves show reddish-purple discoloration.
3. Potassium Deficiency: The leaf margin turns yellow and brown coloration which appears like firing and drying. The symptoms progresses from the lower leaves to the upper leaves.
4. Sulfur Deficiency: Symptoms appears on younger leaves where it will see yellow colour stripping or intervene in alchlorosis.
5. Zinc Deficiency: Upper leaves show broad bands of yellow coloration and later turn pale brown or grey necrosis. The symptom first appears in the middle of leaves and progress outward.
Leaves of corn showing characteristics “V” coloration indicating nitrogen deficiency. Shortening of inter nodes and light streaking of leaves followed by a broad stripe of bleached tissue on each side of the midrib. Occasionally the leaf edges and interior of the stalks at the nodes appears purplish. Field corn plant, the bottom leaf of which is showing symptoms of nitrogen deficiency.
1.15 THE ECONOMIC IMPORTANCE OF MAIZE
1. Maize is a good source of vitamins, minerals and dietary fiber. Especially since a lot of small-scale farmers are involved in maize farming it makes it an affordable source of vitamins and mineral for people living in rural areas.
2. Maize farming can be processed into a number of products which creates an extra source of income of maize farmers, maize processors, and distributor. Some of the products that can be gotten from maize includes:
· Corn Starch: Is used as a thickness for liquid food, is the main ingredient in biodegradable plastic, an ingredient that can be used to replace talc in body powder, and is also used by dry cleaners to keep clothes firm.
· Oil: Corn oil gotten by squeezing the germ of the corn is majorly used to make crunchy, sweet popcorns. It can also be used to make margarine and in the production of soap, cosmetics etc.
· Glue: You can make a business out of processing corn germ into a component that makes industrial glue stronger. The production of industrial glue using corn germ reduces the cost of production.
· Ethanol: An alcohol that can be mixed with gasoline and used in powering vehicles can be made by distilling corn. Gasoline usually contains ethanol in the ration 10:90 (10 – ethanol, 90 – gasoline) in order to oxygenate the fuel and reduce air pollution. Ethanol is an effective solvent that can be used in household products like paints and varnish.
Ethanol is also very effective in killing microorganisms which makes it a common ingredient in cosmetics, beauty products, and hand sanitizers. It’s ability to effectively kill microorganisms makes it an excellent preventive. Ethanol also helps to distribute food colouring.
3. Amazing dish can be made from maize/corn. Corn can be cooked, roasted or blended and used in delicacies like fried rice, jollof rice etc. Blended corn can be used for pancakes, baby food, and baking. Maize is a cereal that is vital to the growth of a child. Aside that, one of the products of maize, cornflakes takes about a minute to preparation time which makes for a quick meal for children.
|BANKING AND FINANCE||11|
|CONSTRUCTION AND BIULDING||1|
|ELECTRICAL AND ELECTRONICS||1|
|ENGLISH LITERARY STUDIES||29|
|GEOGRAPHY AND PLANNING||1|
|HOM SCIENCE AND MANAGEMENT||3|
|LIBRARY AND INFORMATION SCIENCE||4|
|OFFICE TECHNOLOGY AND MANAGEMENT||21|
|SCIENCE LABORATORY TECHNOLOGY||19|
|SOIL AND ENVIRONMENTAL SCIENCE||1|
No data found...