Effect of Combining Rubber Effluent with Rock Phosphate on Some Soil Chemical Properties and Early Growth of Maize (Zea mays. L)
Orhue Ehi Robert,
Uzu Ogbonnaya Frank
Osaigbovo Agbonsalo Ulamen
Studies were conducted at the University of Benin, Benin City, Nigeria to examine the influence of combining rubber effluent with rock phosphate on some soil chemical properties as well as some agronomic characters of maize. The analysis of rubber effluent showed that it contains N, P, K, Ca Mg, Fe Mn, Zn and slightly acidic. It was also observed that the effluent had a pungent odour and colourless. In the first cropping, soil pH, N, Ca, Mg, K Na, Na, Fe, Mn, ECEC and Exchangeable acidity increased while the P and % carbon were reduced compared with control. In the second cropping, all the nutrient elements were reduced further. In the nutrient content of Maize, N, P increased up to 200,000l/(30 kg ha-1) while Ca, Na, Mg, K increased up to 200000l (60 kg ha-1). The trace elements content were not consistent. Similar trends were also recorded in the second cropping but the nutrient contents were reduced further. The N, P, K, Ca, Na, Al, Fe, Zn and Mn uptake were higher at 150,000l (30 kg ha-1) while the Mg uptake was higher at 250,000l (120 kg ha-1) At final harvest, 150,000l (30 kg ha-1) was significantly (p<0.05) better than other treatments including control in plant height, collar girth and leaf area. The number of leaves was not significantly different from one another in all the treatments. In the residual effect, all the agronomic characters measured were almost closing up with the first cropping.
to cite this article:
Orhue Ehi Robert, Uzu Ogbonnaya Frank and Osaigbovo Agbonsalo Ulamen, 2007. Effect of Combining Rubber Effluent with Rock Phosphate on Some Soil Chemical Properties and Early Growth of Maize (Zea mays. L). International Journal of Soil Science, 2: 82-95.
Rock phosphate is considered organic fertilizer and about 90% of the P is usually stable, insoluble in water and largely unavailable. It works best on acid soils high in organic matter (Leonard, 1986). Effectiveness of rock phosphate as a direct application fertilizer is determined by its chemical reactivity which in turn depends on the degree of carbonate substitution for phosphate in the appatite structure (Tisdale et al., 1984). The utilization of phosphate as a source of plant nutrient is influenced by many factors such as fertilizer, soil environment and management. The soil environmental factors that affect phosphorus release and consequently utilization of phosphate when applied to soils are proton buffer, exchangeable calcium, phosphate buffer power, organic matter, soil pH and soil moisture holding capacity (Amapu et al., 2000). Obigbesan and Akirinde (2000) and Gerner and Baanante (1995) have earlier advocated direct application of phosphate sources with a significant content of less soluble phosphorus such as rock phosphate to recapitalize the soils. Direct application of rock phosphate have been reported by Nehikhare (1987) and Chien (1990) to be beneficial. Natarajan et al. (1983) reported increased yield of millet especially when rock phosphate was combined with farmyard manure. Chalwade and Ghousika (1983) also observed that mixing manure with rock phosphate extended the period of phosphate availability to plants.
Rubber effluent on the other hand is known to contain a large amount of non-rubber substances in addition to traces of various processing chemicals. The controlled applications of rubber effluent on land have been reported to cause changes in soil properties. Yeow and Zin (1981) reported improved water retention of soil whereas Poon (1982), Lim and Png (1983) and Lim et al. (1983) reported increased pH and soil K, Ca, Mg as well as organic matter when rubber effluent was applied on the soil. Orhue et al. (2005) reported an improved growth and nutrient uptake when rubber effluent was used on Dialium guineense and maize plants. Information on combining rubber effluent with rock phosphate in an ultisol is rare or scanty. Rubber effluent being an excellent soil conditioner (Seneravitne, 1997) could be use to complement organic fertilizer such as rock phosphate. The objective of this study was to evaluate the effectiveness of rock phosphate in soil amended with rubber effluent using maize as test crop.
MATERIALS AND METHODS
The experiment was conducted in both the greenhouse and laboratory at the University of Benin, Benin City, Nigeria. The topsoil obtained at a depth of 0-15 cm was bulked, mixed thoroughly and a composite sample collected, air dried and then sieved to remove debris. Thereafter, 2 kg of the composite was weighed and put in each of the 180 polythene bags measuring 24x28 cm in size. The experiment was a 6x5 factorial design laid out in a Completely Randomized Design with 3 replicates. Each replicate had 60 polythene bags with 2 polythene bags per treatment. Five levels of Ogun rock phosphate -0, 30, 60, 90 and 120 kg ha-1 were used while rubber effluent was applied at the following rates of 0, 50, 100, 150, 200 and 250 mL/2 kg soil equivalent to 0, 50000, 100000, 150000 200000 and 250000l ha-1. Prior to the application of the rock phosphate, analysis revealed that it contained 9% available P.
Rubber effluent and rock phosphate were applied to the soil in the polythene bags, mixed thoroughly and moistened with deionised water and left for 2 weeks for proper mineralization to enable the phosphate reacts with rubber effluent and the soil The soils were moistened before the seeds were sown. Ten seeds were initially sown and later thinned to one plant per pot. Subsequent moistening to 70% field capacity was carried out every 4 day interval with deionised water. Data collection on plant height, number of leaves, collar girth and leaf area were taken at 8 weeks after planting. Thereafter, the crops were harvested, oven dried to constant weight at 70°C for 48 h. Nutrient uptake was computed as product of dry weight and the nutrient content (%) (Pal, 1991).
The second cropping was conducted to investigate the residual effects of the rock phosphate and rubber effluent. The soils of 180 polythene bags were allowed to be air-dried for 2 weeks after the first harvest and then sieved to remove crop residue. Thereafter, each polythene bag was moistened and then sown again with ten seeds and thinned to one plant per pot 2 weeks after sowing. Watering carried out as previously described in experiment one. Data collections on plant height, collar girth leaf area as well as number of leaves were carried out 8 weeks after sowing. Mode of data collections and measurements of parameters were similar to those of experiment one.
Soil analyses were carried out before and after harvesting of maize. The rubber
effluent was analyzed before using it to pollute the soil while the plant anlysis
was done at the end of each experiment. Particle size analysis was determined
by using hydrometer method of Bouyoucos (1951) while the soil pH was determined
at a soil to water ratio of 1:1 using a glass electrode pH meter. The pH of
rubber effluent was read directly with the pH meter. The electrical conductively
of the effluent was read directly from the CIBA- CORNING conductivity meter.
The organic carbon content of both soil and rubber effluent was determined by
using the chronic acid wet oxidation procedure as described by Jackson (1962).
The total nitrogen, available phosphorus, exchangeable bases as well as exchangeable
acidity were determined using methods of Jackson (1962), Bray and Kurtz (1945)
and Mclean (1965), respectively. The effective cation exchange capacity was
calculated as the sum of exchangeable bases and exchangeable acidity. The aluminum,
iron and manganese were determined by methods described by Chanery (1955), Mehra
and Jackson (1960) and Bradfield (1957), respectively.
Properties of Rubber Effluent
The physico-chemical properties of rubber effluent (Table
1) indicated that the effluent was slightly acidic, colorless and contained
N, P, K, Ca, Na, Mg, Fe, Mn, Zn and organic Carbon.
||Analysis of the rubber effluent used in the experiment
||Physico-chemical analysis of polluted and unpolluted soil
after harvest of maize plant in first cropping as influence by rubber effluent
Properties of Soil Used
The properties of soil used in the entire trial are shown in Table
2. The soil is moderately acidic. It is classified as Ultisol, Dystric Nitosol,
Benin Fasc, grey in colour and texturally sandy (Enwezor, 1990). The soil contained
organic carbon, N, P exchangeable cations, exchangeable acidity, Effective Cation
Exchange Capacity (ECEC) as well as trace elements such as iron, manganese and
The Physico-chemical Properties of Soil After Harvesting
The soil pH increased from 5.10 to a mean between 6.07 in 60 and 6.99 90
kg ha-1 in first cropping (Table 2) while in the
second cropping (Table 3) the soil pH was raised from 5.10
to a mean of between 5.15 in control and 6.70 in 100,000l (90 kg ha-1).
The application of effluent-rock phosphate combination in first cropping reduced
the 1.32% carbon in control to a mean of between 1.11 and 1.18% (Table
2). The total nitrogen was increased from 0.05% in control to a mean of
between 0.54% in 60 and 90 kg ha-1 and 0.88% in 200000l (90 kg ha-1)
(Table 2). In the second cropping (Table 3)
the carbon was reduced further to a mean of between 0.90% in 250,000l (60 kg
ha-1) and 1.10% 50,000l (90 and 120 kg ha-1) (Table
3). The nitrogen was reduced further to a mean value of between 0.50 and
0.72% in n100,000l (90 kg ha-1). The phosphorus level was reduced
from 4.71 ppm to a mean of between 1.02 in control and 2.95 ppm in 100000l (90
kg ha-1) (Table 2) in first cropping and to a mean
of between 0.96 ppm in 150,000l ha-1, 200,000l ha-1 and
200,000l (30 kg ha-1) and 2.20 ppm in 120 kg ha-1 in the
second cropping (Table 3).
In the first cropping mono-valent cations such as K and Na were raised from
0.04 and 0.08 in control to a mean value of between 0.61 cmol kg-1
in control and 11.92 cmol kg-1 in 50,000l (90 kg ha-1)
and 1.73 cmol kg-1 in 150,000l (60 kg ha-1) and 3.39 cmol
kg-1 in 100,000l (120 kg ha-1), respectively whereas the
divalent cations such as Ca and Mg were increased from 0.01 and 1.39 cmol kg-1
in control to a mean value of between 2.01 cmol kg-1 in control and
5.61 cmol kg-1 in 100,000l (90 kg ha-1) and 1.57 cmol
kg-1 in 60 kg ha-1 and 3.92 cmol kg-1 in 250,000l
(90 kg ha-1), respectively (Table 2). The exchangeable
acidity and Effective cation exchange capacity rose from 0.08 and 1.60 cmol
kg-1 in control to a mean value of between 1.00 cmol kg-1
in 50,000l (120 kg ha-1) 100,000/ (90 kg ha-1), 250,000l
(90, 120 kg) and 2.40 cmol kg-1 in 150,000l ha-1 and 9.77
Cmol kg-1 in control and 23.28 cmol kg-1 in 100,000l (120
kg ha-1), respectively (Table 2). The K and Na
monovalent cations and Ca and Mg divalent cations were further reduced in the
second cropping (Table 4) to a mean value of between 0.50
cmol kg-1in control and 9.51 cmol kg-1 in 50,000l (90
kg), 0.92 in 200,000l ha-1 and 1,99 cmol kg-1 in 100,000l
(120 kg ha-1), 1.70 in control and 6.07 cmol kg-1 in 100,000l
(120 kg ha-1) and 0.96 in 60 kg ha-1 and 2.58 Cmol kg-1
in 250,000l (90 kg ha-1), respectively. The exchangeable acidity
and effective cation exchange capacity were reduced further to mean value of
between 1.08 in 250,000l (90 kg ha-1) and 2.40 cmol kg-1
in 150,000l ha-1 and 8.01 cmol kg-1 in control and 20.56
cmol kg-1 in 50,000l (90 kg ha-1), respectively (Table
3). In the first cropping (Table 2), trace elements such
as zinc, iron and manganese were raised from 0.65, 0.01 and 0.05 ppm, in control
to a mean value between 0.58 ppm in 60, 90 and 120 kg ha-1 and 0.89
ppm in 100,000l (90, 120 kg ha-1), 0.15 in 250,000l (90 kg ha-1)
and 0.40 ppm in 90 kg ha-1, 0.12 ppm in 250,000l (90 kg ha-1)
and 0.32 ppm in 120 kg ha-1, respectively whereas in the second cropping
(Table 3), zinc was further decreased to a mean value between
0.40 ppm in 90 kg ha-1, 200,000l (90 and 120 kg ha-1),
250,000 (90 and 120 kg ha-1) and 0.57 ppm in 150,000l and 150,000l
(90 and 120 kg ha-1) Iron was reduced to a mean value of between
0.13 ppm in 50,000l (90 and 120 kg ha-1) and 0.35 ppm in 60 kg ha-1
while manganese had a mean of between 0.11 ppm in 250,000l (90 and 120 kg ha-1)
and 0.27 ppm in 90 kg ha-1.
||Physico-chemical analysis of polluted and unpolluted soil
after harvesting of maize in second cropping as influenced by residual effect
of rubber effluent and phosphorus
In both first and second cropping, it was however observed that soil texture
was not affected by the various rubber effluent-phosphorus combinations as well
as control (Table 2 and 3).
Nutrients Content of Maize Plants
The nutrient content of the maize plant in first and second cropping are shown
in Table 4 and 5. In the first cropping
(Table 4) that N, P, Na, Ca, Mg, K, Al, Fe, Mn and Zn had
mean value of between 1.5% in control and 2.29%, in 100,000l, 0.086% in 30 kg
ha-1 and 0.118% in 150000l and 150,000l (120 kg ha-1),
0.032% in 250000l (90, 120 kg ha-1) and 0.039% in 100,000l (30 kg
ha-1), 150000l (30, 60 90, 120 kg ha-1), 0.059% in 30
kg ha-1 and 0.113% in 200000l (30, 60 kg ha-1), 0.063%
in 150,000l ha-1 and 0.621% in 250,000l (30, 90, 120 kg ha-1),
1.030 in 200,000l ha-1 and 1.570% in 150,000l ha-1, 120
mg kg-1 in 200,000l (30, 60, 90, 120 kg ha-1) and 206
mg kg-1 in 250,000l ha-1, 51 mg kg-1` in 150,000
(60, 120 kg ha-1) and 70 mg kg-1 in 50,000 (0, 60 kg ha-1),
49 mg kg-1 in 60 kg ha-1 and 54 mg kg-1 in
250,000l (30 kg ha-1), 39 mg kg-1 in 200,000l ha-1
and 44 mg kg-1 in 50,000l (60, 90 kg ha-1), respectively.
In the second cropping (Table 5) the mean nutrient content
were between 1.40% in 90 kg ha-1 and 2.25% in 100,000 (30 kg ha-1)
for N, 0.075% in control and 0.098% in 150,000l (90 kg ha-1) for
P, 0.030% in control and 150,000l (0. 30 kg ha-1) and 0.034% in 100,000l
(90, 120 kg ha-1) for Na, 0.052% in control and 120 kg ha-1
and 0.105% in 150,000l (30 kg ha-1) for Ca, 0.060% in 150 kg ha-1
and 0.232% in 50,000l (30 kg ha-1) for Mg, 0.98% in 250,000l (0,
60, 90, 120 kg ha-1) and 1.298% in 120 kg ha-1 for P,
101 mg kg-1 in 250,000l (30, 60 kg ha-1) and 143 mg kg-1
in 50,000l (30 kg) for Al, 40 mg kg-1 in 150,000l (0, 60, 120 kg
ha-1), 200,000l (0, 30 kg ha-1) and 64 mg kg-1
in 50,000l (0, 30 kg ha-1) for Fe, 40 mg kg-1 in 200,000l
ha-1 and 46 mg kg-1 in 50,000l (30, 90 kg ha-1)
and 90 kg ha-1 for Mn, 34 mg kg-1 in 200,000l ha-1,
250,000l (30, 60, 90, 120 kg ha-1) and 50,000l (30, 60 kg ha-1)
and 39 mg kg-1 in 150,000l (30, 60, 90, 120 kg ha-1) for
||Effect of rubber effluent and phosphorus on nutrient content
of maize plant in first cropping
||Effect of rubber effluent and phosphorus on nutrient content
of maize plant in second cropping
||Effect of rubber effluent and phosphorus on nutrient uptake
by maize plant in the first cropping
The N and P increased up to 200,000l (30 kg ha-1) while Ca, Na,
Mg and K increased up to 200,000l (60 kg ha-1). The trace elements
nutrient content was not consistent.
Nutrient Uptake by Maize Plant
The N and P uptake in first cropping (Table 6) indicated
that there were progressive increase from control-phosphorus combinations up
to 150,000l (30 kg ha-1) and declined gradually. The N mean value
was between 364.44 mg/plant in 30 kg ha-1 and 1,105.93 mg/plant in
150,000l (30 kg ha-1) whereas P mean value was between 17.33 mg/plant
in control and 61.87 mg/plant in 150,000l (30 kg ha-1). There was
no consistency in the Ca, Na P, Al, Mn and Zn uptake in various effluent- phosphorus
combinations in first cropping (Table 6). The Ca uptake however
had a mean value of between 12.88 mg/plant in control and 51.91 mg/plant in
150,000l (30 kg ha-1), Na had between 7.79 mg/plant in control and
18.05 mg/plant in 150,000l (30 kg ha-1) while Mg was between 17.94
mg/plant in 150,000l ha-1 and 162.60 mg/plant in 250,000 (120 kg
ha-1). K, Al, Fe Mn and Zn mean value were between 259.38 mg/plant
in 250,000l (90 kg ha-1) and 712.30 mg/plant in 150,000l (30 kg ha-1),
0.29 mg/plant in 200,000l (30, 60 kg ha-1) and 0.56 mg/plant 150,000l
(30 kg ha-1), 0.140 mg/plant in 200,000l (30 kg ha-1)
and 0.243 mg/plant in 150,000l (30 kg ha-1), 0.111 mg/plant in control
and 0.234 mg/plant in 150,000l (30 kg ha-1), 0.081 mg/plant in 200,000l
ha-1 and 0.189 mg/plant in 150,000l (30 kg ha-1), respectively
in the first cropping (Table 6). In the second cropping (Table
7) similar trends in various nutrient uptakes as shown in first cropping
were also recorded.
||Effect of rubber effluent and phosphorus on nutrient uptake
by maize plant in the second cropping
||Effect of rubber effluent and phosphorus application on the
leaf area, collar girth (cm), number of leaves, plant height (cm) of maize
plant in first and second cropping
|Means followed by the same letter in the column are not significantly
different from one another at 5% level of probability
The vegetative growth parameters measured in first and second cropping are
depicted in Table 8. In the number of leaves, there were no
significant differences among the treatments in both first and second cropping.
However, the highest number of leaves were recorded in first and second cropping
at 150,000l (30, 60, 90, 120 kg ha-1). Also in plant height, treatment
combination of 150,000l (0, 30, 60, 90, 120 kg ha-1) were not significantly
different from one another but better than other treatments in first cropping
whereas in the second cropping treatments 150,000l (0, 30, 60, 90, 120 kg ha-1),
200,000l (0, 30, 60, 90, 120 kg ha-1) and 250,000l (0, 30, 60, 90,
120 kg ha-1) were not significantly different from one another but
better than other treatments including control. The treatment combinations of
150,000l (0, 30, 60, 90, 120 kg ha-1) were not significantly different
from one another but better than other treatments in both first and second cropping
in collar girth. The leaf area were also not significantly different from each
other at 150,000l (90, 120 kg ha-1) in the first cropping and at
150,000l (30, 60, 90, 120 kg ha-1) in the second cropping but they
were better than other treatments including control.
The soil used is a typical Ultisol low in fertility as shown by its properties. This result is similar to the findings of Agboola and Ogunkule (1993). The properties of the effluent showed that it contains some both micro and macro nutrients that can be utilized by crops. Similar results have also been recorded by Seneviratne (1997) and Orhue et al. (2005). The basic facts according to Orhue et al. (2005) is that most of the effluents whether obtained from processing of crepe, crumb, concentrate latex contain the basic plant nutrients.
The increase in the soil pH, N, K, Ca, Mg, Na is attributed to the nutrient properties (Serum) of the effluent as well as the phosphorus applied. Similar results have earlier been reported by Poon (1982) Lim and Png (1983) and Lim et al. (1983). The increase in above nutrients further confirms that applying effluent alone or combining it with phosphorus is not problematic especially when the rate of application is geared to supply nutrients at levels corresponding to those in inorganic fertilizer normally applied to promote satisfactory crop performance and that controlled application of effluent causes no detrimental changes in the soil. Rather it improves soil fertility and has no apparent adverse effect on the environment. Also the gains or beneficial properties of rubber effluent as an excellent soil conditioner makes it a good source of fertilizer. The decrease in P with increase in effluent-phosphorus combination may be due to overlapping of sphere of soil serving as a sink for the dissolution products of adjacent P fertilizer particles which could have influenced dissolution (Elraside and Larson, 1978). The practical consequence of this would be a progressive decline in the agronomic effectiveness of a given quantity of P fertilizer as rate of application increases (Amapu et al., 2000) and this is primarily due to the build-up of products of dissolution on the surface of the fertilizer particles. This result suggests that it is not advisable to rapidly raise the soil P status by the application of large doses of P fertilizer.
The utilization of rock phosphate is influenced by some soil factors which affect the dissolution and consequently its release of P. Some of the factors according to Amapu et al. (2000) include soil pH, proton buffer power, exchangeable Ca, phosphate buffer power, organic matter, soil moisture holding capacity. The decrease percentage carbon is however contrary to the finding of Lim et al. (1983) and Seneviratne (1997). Although there were no definite pattern of exchangeable acidity, ECEC, Fe, Mn, Zn, there were slight increase compared with control. The soil texture was never influenced or changed by the effluent-phosphorus combinations. The increases in nutrient content of the maize plants except N and P in the trials were not definite. This may be attributed to the nutrient uptake ability of the maize plant, soil nutrient interaction as well as an indication that the effluent phosphorus combination should be at the rates corresponding to crop requirements..
There is generally a relationship between some of the major elements especially N, P and K, Mg (Remison and Snaydon, 1981; Remison and Okpala-Jose, 1992). The supply of one element can increase, decrease or maintain their percentage in dry matter in the leaves (Remison, 1997). The effects are described as antagonistic when the leaf nutrient of an element is reduced by the application of another element and synergetic when application increases the leaf content of element concentrated (Remison, 1997). These effects tend to influence nutrient uptake and subsequent nutrient content of plant. The increase in N, P, K, Ca, Mn uptake up to 200,000 (90 kg ha-1) showed that the effluent-phosphorus combinations should be applied at the rate corresponding to the plant requirement. The uptake of Mg, Na, Al, Zn, Mn were however not definite. This variation in nutrient uptake may have been influenced by certain factors such as temperature, aeration, plant age, concentration of competing ions as well as nutrient interaction in the soil. All these may have differential effects upon nutrient uptake rate and subsequent different nutrient composition (Clinton and William, 1981; Drewes and Blume, 1997; OConner and Anderson, 1997). Loos et al. (1979) asserted that reduce nutrient uptake in the presence of effluent could occur due to strong adsorption or degradation in the soil and that the extent of absorption or degradation does not only depend on the properties of the effluent but also on the properties of the site, soil types, kind of soil organisms and climatic conditions.
The increase in the plant height, leaf area and collar girth up to 150,000l
(120 kg/ha) combination indicated that both effluent and rock phosphate can
compliment each other and that the optimum growth at 150,000l (30 kg ha-1)
is a matter of crop preference and the depression in height, girth and leaf
area as from 200,000l ha-1 effluent with various rock phosphate combinations
could be due to effluent and phosphorus interactions with other elements in
the soil. The residual effect on the vegetative growth was also glaring such
that the effluent-rock phosphate combination was almost closing up with first
cropping indicating that rock phosphate availability to plant is slow and dependent
on soil factors such as soil pH. This result confirms that, in slightly acid
soils the performance of rock phosphate is often inferior. Obigbesan and Mengel
(1981), Chien et al. (1989) and Chien (1990) showed that a finely ground
rock phosphate can be as effective as water soluble P-fertilizer particularly
in strongly acidic soils. The improvement effect of the rock phosphate over
the control and better performance in the second cropping is a clear indication
of the rock phosphate efficacy as viable alternative P-source for direct use
in the long run. Strongly acid soil can bring about favorable residual effects
by releasing much of the P gradually for plant use. The presence of anthocyanin
purple colorations in the maize plants treated with rock phosphate is an indication
of P-deficiency at the early growth of the plant. This confirms that rock phosphate
availability to plant is slow. Similar results have earlier been obtained by
Mengel and Kirkby (1987) and Obigbesan and Akinrinde (2000).
The study revealed that application of effluent-phosphorus combination had an effect on the uptake, synthesis and translocation of vital mineral elements in maize plants. The vegetative growths as well as soil nutrient elements were enhanced greatly. However, maize plant that received higher rate effluent-phosphorus combination greater than 150,000l ha-1(120 kg ha-1) had a declined vegetative growth as well as reduced nutrient elements levels in the soil showing the existence of interaction between effluent and phosphorus with other nutrient elements in soil.
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