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1Dept. of Arid land Agriculture, King A/Aziz University, Jeddah, Saudi Arabia ... the Demonstration Farm of the Faculty of Agriculture at Shambat, University of ...
AGRICULTURE AND BIOLOGY JOURNAL OF NORTH AMERICA ISSN Print: 2151-7517, ISSN Online: 2151-7525, doi:10.5251/abjna.2011.2.1.109.124 © 2011, ScienceHuβ, http://www.scihub.org/ABJNA

Effect of intercropping, phosphorus fertilization and rhizobium inoculation on the growth and nodulation of some leguminous and cereal forages Awad O. Abusuwar1 and Eltahir A. Omer2 1

Dept. of Arid land Agriculture, King A/Aziz University, Jeddah, Saudi Arabia E-mail: [email protected] 2 Faculty of Natural Resources, University of Upper Nile, Malakal, Sudan ABSTRACT

A field experiment was carried out for two consecutive seasons (2005/2006 and 2006/2007) in the Demonstration Farm of the Faculty of Agriculture at Shambat, University of Khartoum, Sudan, to study the effect of intercropping, phosphorus application and Rhizobium inoculation on the performance of some leguminous and cereal forage crops. The treatments used were pure stand, a mixture of Clitoria, lablab and Sudan grass, phosphorus fertilizer and Rhizobium inoculation. They were laid out in a completely randomized block design with three replications. Growth attributes, number of nodules, weight of nodules and prussic acid (HCN) were measured. Results showed that stem thickness was significantly affected by intercropping and addition of phosphorus. Sole crops produced forage with thicker stems during the growth of the first crop, while intercropped plants treated with phosphorus developed thicker stems during the second cut (ratoon). The plant cover was significantly higher for Clitoria than the other species. Intercropping and addition of phosphorus increased plant height of Sudan grass. The leaf area of Clitoria was increased with the addition of phosphorus and intercropping in the first crop, but sole Clitoria scored higher leaf area during the second cut. Lablab leaf area was significantly increased with addition of phosphorus and intercropping in the two seasons. Intercropping of Sudan grass with lablab and Clitoria resulted in large leaf area of Sudan grass. Leaf to stem ratio of Clitoria was mainly increased with the addition of phosphorus. Intercropping lablab with Clitoria significantly increased lablab leaf to stem ratio. The two-combination intercropping of Sudan grass increased its leaf to stem ratio. Rhizobium inoculation, legume to legume intercropping and addition of phosphorus enhanced nodulation and increased the number and weight of nodules. Phosphorus significantly reduced the amount of HCN in the forage of Sudan grass. Keywords: intercropping, bio-fertilization, grass-legume mixture, phosphorus fertilization INTRODUCTION Sustaining bio-diversity in nature is very crucial, simply because of human intervention through the process of isolating certain plants from their communities, which affects the natural distribution of plants in nature. Intercropping is the growing of two or more crops on the same land and at the same time. It is one of the methods used to return plant configuration to its natural diversity. Bio-fertilization is the use of organic matter or microbiological inoculation to increase soil fertility. Rhizobium plays an important role in agriculture by inducing nitrogen fixing nodules on the roots of legumes. Nitrogen fixation is one of most important biological processes on earth (Graham, 2008) and Rhizobium inoculation of legumes is one of the success stories of world agriculture (Herridge, 2008).

The process of nitrogen fixation is much cost energetically. Addition of nitrogen through the process of nitrogen fixation is cheap to the farmer, without any hazards, avoiding the use of chemical fertilizer. Intercropping of non-legume and leguminous crops probably reduce competition for nitrogen . Lablab bean is a very excellent nitrogen fixer, it is used for human consumption, cover crop and for animal feeding. Clitoria combines well with Sudan grass and some other crops, beside its palatability and nutritional value for animal. The peculiarity of the family Fabaceae is the production of bacterial nodules. Roots of leguminous plant infected by bacteria of the genus Rhizobium form nodules that vary in number and size. Sorghum sudanense a non-leguminous crop that needs large amounts of nitrogen from the soil. The presence of Clitoria and hyacinth bean in the

Agric. Biol. J. N. Am., 2011, 2(1): 109-124

intercropping system with Sudan grass will help the availability of nitrogen through the process of Nfixation (nodules). The success of this process depends on the amount and activity of the bacteria in the soil.

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Sorghum sudanense + Phosphorous Clitoria ternatea + Phosphorous Lablab purpureus + Phosphorous Sorghum sudanense: Lablab purpureus : Clitoria ternatea + Phosphorous 11- Sorghum sudanense: Lablab purpureus : Clitoria ternatea + Phosphorous + Rhizobium 12- Clitoria ternatea + Rhizobium 13- Lablab purpureus + Rhizobium 14- Clitoria ternatea : Lablab purpureus 15- Clitoria ternatea: Lablab purpureus+ Phosphorous 16- Clitoria ternatea: Lablab purpureus+ Rhizobium 17- Clitoria ternatea: Lablab purpureus+ Phosphorous+ Rhizobium 18- Sorghum sudanense: Clitoria ternatea+ Phosphorous 19- Sorghum sudanense : Clitoria ternatea+ Rhizobium 20- Sorghum sudanense: Clitoria ternatea+ Rhizobium + Phosphorous 21- Clitoria ternatea + Rhizobium+ Phosphorous 22Lablab purpureus + Rhizobium+ Phosphorous 23- Sorghum sudanense: Lablab purpureus : Clitoria ternatea+ Rhizobium 24- Sorghum sudanense : Lablab purpureus+ Phosphorous 25- Sorghum sudanense : Lablab purpureus+ Phosphorous+ Rhizobium 26- Sorghum sudanense : Lablab purpureus + Rhizobium Treatments were replicated three times and the number of experimental plots were equal to 78 using a Randomized Complete Block Design.

Sudan grass like many other members of the family Poaceae, (Johnson grass and Sorghum) contains cynogenic glycoside, which produces prussic acid (poisonous substance to animals) (Abusuwar, 2005). Prussic acid (HCN) inhibits oxygen utilization by the cells in the animal body, cattle and sheep (ruminant) are more susceptible. The addition of phosphorus reduces the amount of this substance in the plant tissues, and increases the resistance to plant lodging. Phosphorus is the component of the genetic materials (DNA and RNA) and an essential element in all living cells. Therefore, the main objective of this study was to explore the possibility of providing green forage from an intercropping system of leguminous and nonleguminous crops with high productivity and high nutritional value. The specific objectives were to: astudy the effect of phosphorus fertilization and Rhizobium inoculation on the growth and yield of cereal and leguminous forage crops, and b-evaluate mixed cropping versus monocropping systems. MATERIALS AND METHODS Experimental site description: The Demonstration Farm of the Faculty of Agriculture at Shambat (latitude 15°40'N and longitude 32°32'E and altitude 280 m above sea level) has a semi-desert climate with annual precipitation between 100 and 200 mm. o o and a temperature ranges from 12 C to 42 C. (Shambat Meteorological Station,2008).

Inoculation: The leguminous seeds were inoculated before planting with their Rhizobium strains in form of black powder, brought from the National Research Center and USDA3398 for Lablab and USDA3384 for Clitoria

Land preparation: Four operations were carried out; ploughing, harrowing, leveling, and ridging 70 cm apart. The size of the plot was 3 x 5 m with six ridges. The experimental plots were protected with a guard area planted with Sorghum. Treatments Treatments used were: 1- Sorghum sudanense (pure stand) 2- Clitoria ternatea (pure stand) 3- Lablab purpureus (pure stand) 4- Sorghum sudanense: Clitoria ternatea 5- Sorghum sudanense: Lablab purpureus 6- Sorghum sudanense: Lablab purpureus : Clitoria ternatea

 

Phosphorous addition: Phosphorous was added in the form of triple supper phosphate at a rate of 50 kg per hectare before planting. Seed rate: For sorghum, Clitoria and lablab, seeding rates applied were, 10, 15, 20 kg/feddan, respectively. In case of mixture, the seed rate was half or third of that of the sole crop (half incase of two mixtures and third incase of three mixtures).

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HCN content = glycoside concentration  1.03  1000 /10.5

Sowing date: The first and the second season experiments were planted at the first week of March 2005 and 2006.The first ratoons started after harvesting.

Data analysis: Randomized Complete Block Design was used, in which the main 26 treatments were further fractionated to obtain 16 ,16, and 12 treatments consisted of Clitoria, Lablab and Sorghum, respectively and each crop was statistically analyzed separately

Method of planting: Seeds of legumes were drilled into the shoulders of the ridges, alternated with Sorghum seeds, row intercropping (1: 1) Irrigation: The experiment was irrigated immediately after planting to avoid death of bacteria ( Rhizobium ) and weekly thereafter.

RESULTS Stem diameter (cm) Clitoria ternatea: Clitoria thickness was significantly different with treatments in all readings except the first reading of the two seasons (Tables 1a and 1b). Stem diameter increased with plant age. In the second readings it was significantly affected by treatments and sole Clitoria treated with P gave the thickest stems among the treatments of the second reading of the two seasons (0.38cm for the first season and 0.57cm for the second season).

Weed control: The most common weeds were Buda (Striga hermonthica), Nageela (Cynadon dactylon) and Saeda (Cyprus rotundus). Weeding was carried out once after three weeks from planting. White fly was the most common insect infested lablab plants, but did not reach threshold level. Parameters measured: Five tagged plants for each crop in the plot were taken at random from the middle rows to measure growth parameters.

At time of harvest in the first season, Clitoria (CL) treated with phosphorus (P) and Rhizobium ( R) resulted in thicker plants (0.51 cm), whereas CL/P/R treatment gave the thickest stem in the second season (0.78cm). Addition of P and R relatively increased plant thickness.

Stem diameter: It was taken from the second internodes at the base of the plant after 15 days from planting and one month thereafter using a Vernia. Leaf area: For sorghum plant, leaf number four from the top was used to determine the leaf area by leaf area meter. For leguminous plants, a fully grown compound leaf was chosen randomly to measure the leaf area, at one month interval.

Ratoon plant was thicker than the first cut. First season ratoon gave plant with stem diameters ranged between 0.61 and 1 cm, whereas second season ratoon ranged between 0.48 and 0.92 cm. Lablab purpureus: Stem diameter in the first and second reading of the first season did not respond significantly to the treatments, even though sole lablab developed thicker stem in the first reading and CL/P/R in the second reading.

Leaf-to-stem ratio: The weight of removed leaves of five randomly selected plants was divided by the weight of their stems at one month interval. Number and weight of nodules: Three plants were uprooted for recording nodulation. Nodules were removed from roots of legumes, counted; fresh and dry weights were determined. This was done twice; six weeks from planting and at harvest.

Treatments in the first reading of the second season revealed significant difference for stem diameter (SD), in which LC/R treated plants were significantly thicker than non-treated plants (1.38cm). Planting lablab with Sorghum and Clitoria gave relatively thinner stems. At the time of harvest of the first cut lablab grown alone and lablab treated with P and R yielded thicker stems (1and 0.95cm, respectively). Last reading of the second season showed that L/P/R treatment had the thicker stems (1.37cm) and generally sole lablab obtained thicker stems.

Prussic acid: This parameter was taken at the time of harvest, for the main crop and the ratoon. Five Sorghum plants were taken randomly, milled using pressure machine; the extracted juice was collected, filtered and centrifuged. The Spectrophotometer was used to determine the absorption of juice at wave length (λ) =293 nm, glycoside concentration was calculated according to the formula described by British Pharmacopoeia (1980).

 

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Agric. Biol. J. N. Am., 2011, 2(1): 109-124 Table 1.a. Effect of intercropping, phosphorus and inoculation on stem diameter (cm) of Clitoria, lablab and sorghum (2005)

Treatment

st

1 reading

Clitoria nd st 2 At 1 reading harvest

nd

st

Lablab nd st 2 At 1 reading harvest

nd

Sorghum nd st 2 At 1 reading harvest

At 2 harvest

0.54abc

0.48a

0.57bcde

0.16a

0.42c

0.47a

0.56bcde

0.22a

0.5abc

0.46a

0.69bcd

0.42c

0.38a

0.60bcde

0.53abc

0.55a

0.76ab

0.67a

0.55a

0.56bcde

0.27a

0.36ab

0.36a

0.71bc

0.38a

0.48abc

0.39a

0.55bcde

1 reading 0.367s

0.68a

0.95a

1.31ab

0.367a

0.55a

0.88

0.53e

SL

0.31a

0.65a

0.76abcd

1bcd

SL /R

0.367a

052a

0.64cd

1.32ab

0.31a

SL/P

0.363

0.60a

0.753abcd

1.28abc

0.20a

SL/P/R

0.357a

0.61a

072abcde

0.93bcde

0.21a

L

0.39a

0.69a

1a

0.997bcde

L/P

0.38

0.69a

0.71bcd

1.5a

L /P/ R SCL

0.16a

0.28abc

0.42ab

1a

SC/P/R

0.17a

0.31abc

0.493ab

0.69def

At 2 harvest

st

At 2 harvest

S SCL/P/R

0.010a

0.27abc

0.35

0.686def

L/R

0.57a

0.51a

0.71bcd

0.87de

0.33a

0.637a

0.62cd

1.46a

1 reading 0.18a

SCL/R

0.20a

0.31abc

0.46ab

0.72cdef

38.a

0.64a

0.83abc

0.867de

0.27a

0.65a

0.48a

0.51cde

SCL/P

0.167a

0.7abc

0.46ab

0.77bcdef

0.38a

0.60a

0.75abcde

0.9cde

0.25

0.5abc

0.50a

0.54cde

C/P

0.203

0.8a

0.44ab

0.77bcdef

C/P/R

0.11a

0.28abc

0.51a

0.87abc

SC

0.16a

0.28abc

0.39ab

0.80bcde

0.19a

0.54abc

0.48a

0.49de

SC/R

167a

0.37ab

0.39ab

0.64ef

0.29a

0.38c

0.38a

0.47e

SC/P

0.19a

0.29abc

0.46ab

0.61f

0.25a

0.41c

0.40a

0.39e

0.22a

0.43bc

0.44a

0.91a

0.02

0.02

0.07

21

29.4

8.6

S/P C

0.18a

0.29abc

0.47ab

0.90ab

CL/P

0.13a

0.26bc

0.34b

0.85abcd

033a

0.72a

0.68bcd

0.75de

CL

0.20a

0.31abc

0.49ab

0.77bcdef

0.33a

0.633a

0.747abcd

0.80de

C/R

18.a

0.30abc

0.45ab

0.70cdef

CL/R

1.10a

.0.26bc

0.40ab

0.75bcdef

0.325a

0.75a

0.70bcde

0.84de

CL/P/R

0.21a

0.28abc

0.42ab

0.90ab

0.375a

0.77a

080abc

0.79de

SE±

0.007 0.007 0.01 0.01 0.02 0.02 0.02 0.3 0.02 CV 28.6 17.2 17.18 9.57 31.8 18.1 16.04 17.3 60.2 Means with the same letter (s) within each column are not significantly different at 0.05 level using Duncan’s Multiple Range Test. Legend: C = Clitoria, L = lablab, S = sorghum, P = phosphors, R = Rhizobium Table 1.b. Effect of intercropping, phosphorus and inoculation on stem diameter (cm) of Clitoria, lablab and sorghum (2006) Treatment Clitoria Lablab

 

nd

112

Sorghum

Agric. Biol. J. N. Am., 2011, 2(1): 109-124 st

nd

st

nd

st

nd

At 1 harvest

st

At 2 harvest

1.19ab

1.37a

1.4bdce

0.84bc

0.87ab

0.75ef

1 reading

2 reading

At 1 harvest

At 2 harvest

1 reading

2 reading

0.37ab

SCL

0.18

0.43

0.34ab

0.87ab

0.32abc

SC/P/R

0.167a

0.39b

0.47ab

0.60bcde

L /P/ R

nd

nd

st

nd

2 reading

At 1 harvest

At 2 harvest

0.21a

0.55a

0.71ab

0.77defg

0.20a

0.68a

0.70ab

0.57defg

SL

0.35abc

0.81bc

0.77b

0.897def

0.10b

0.53a

0.56b

0.74cdef

SL /R

0.25c

0.87bc

0.9ab

1.2bdef

0.11b

0.61a

0.67

1.11a

SL/P

0.30abc

0.92bc

0.93ab

1.27fbdef

0.14ab

0.52a

0.76ab

1abc

1.57bdc

0.14ab

0.68

0.78ab

0.82bcde

SL/P/R

0.28bc

0.83bc

0.99ab

L

0.30abc

0.93bc

1.012ab

L/P

0.28bc

0.987abc

0.9ab

1.77abc

0.26c

0.86bc

0.83ab

1.17bcdef

0.26c

1.11abc

0.92ab

1.8ab

0.31

0.81c

0.93ab

0.28bc

0.79c

0.81

S SCL/P/R

0.13a

0.5b

0.53ab

0.67bcdef

L/R SCL/R SCL/P

0.14a

0.45b

0.44ab

0.2a

0.44b

0.42ab

0.92a 0.697abcd e

C/P

0.19a

0.49b

0.57a

0.58def

C/P/R

0.14a

0.40b

0.43a

0.71abcdef

0.15ab

0.57a

0.65ab

0.8bcdef

0.167ab

0.66a

0.72ab

0.51fg

1.1cdef

0.167ab

0.59a

0.78ab

1.04ab

0.83ef

0.10b

0.53a

0.82a

0.62defg

0.13ab

0.52a

0.61ab

0.52efg 0.53defg

SC

0.17a

0.43b

0.48ab

0.62cdef

SC/R

0.13a

0.44b

0.49ab

0.67bcdef

0.13

0.63a

0.72ab

SC/P

0.13a

0.42b

0.43ab

0.54ef

0.14ab

0.523a

0.61ab

0.41g

0.13ab

0.57

0.69ab

0.82bcd

0.006

0.02

0.017

0.02

27.3

25.3

16.4

21.08

S/P C

0.167a

0.40b

0.37b

0.60dcef

CL/P

0.14a

0.48b

0.53ab

0.79abcd

0.29abc

1.003abc

0.78b

0.63f

CL

0.13a

0.44b

0.50ab

0.73abcde

0.31abc

1.01abc

0.87ab

0.59f

C/R

0.15a

0.46b

0.40ab

0.48f

CL/R

0.13a

0.537b

0.53ab

0.83sbc

0.287abc

1.34a

1ab

2.3a

CL/P/R

0.177

0.7a

0.36b

0.81abcd

0.38a

1.22ab

0.72b

0.84ef

SE±

0.01 0.017 0.01 0.02 0.07 0.04 0.05 CV 29.7 25.7 21.4 18.08 15.8 29.5 29.19 Means with the same letter (s) within each column are not significantly different at 0.05 level using Duncan’s Multiple Range Test. Legend: C = Clitoria, L = lablab, S = sorghum, P = phosphors, R = Rhizobium

 

st

1 reading

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Ratoon plants were thicker than the first crop plants. In the first year, lablab treated with P and R gained the thickest stems (1.5 and 1.46cm), whereas in the second year, LC/R produced the thickest stems (2.3cm). Generally, lablab grown alone developed thicker stems.

The leaf area of the ratoon plant was more or less similar to that of the first cut. Sole Clitoria treatment was the best one (52.5 cm2), CLS/R gained the smallest size (29.3 cm2). Although most of intercrop treatments were statistically not significant, but there were differences among means, in which mono-crops and double crops were having largest leaf areas. Phosphorus slightly increased the leaf area.

Sorghum sudanense: There were significant differences in stem diameter (SD) throughout the different samplings and harvests except for the first sampling and first harvest in year one and the second sampling of year two.. Unlike Clitoria and lablab, sole sorghum in most treatments gave thinner stems compared with intercropping. The SD of the first cut of the two seasons did not reach 1cm and in the last reading of the first year the SD ranged between 0.36 and 0.55cm, whereas first crop SD ranged between 0.56 and 0.82cm. Addition of P was observed to increase SD.

Second season (2006), first reading plants produced large leaves compared with the first reading of the first season. Clitoria: Lablab/P/R treatment revealed plants with the largest leaf size (25.11 cm2) and the C/P/R treatment resulted in the smallest leaf area (9.32 cm2). Intercropping, addition of phosphorus and inoculation did not significantly affect the leaf area. Even second reading was not significantly different; Clitoria: Lablab /P/R treatment gained the largest leaf area (54.17 cm2). Last reading showed significant difference among treatments. Clitoria treated with P and R was the best treatment (86.2 cm2) with the largest leaf area throughout the two seasons. Clitoria: Sorghum: Lablab, CS/P/R, CL/P, CL/R, C/R and CL/P/R treatments were not significantly different. Intercropping Clitoria plant with sorghum resulted in smaller leaf area. Addition of either P or R to the soles and intercrops did not affect leaf area.

The SD of the ratoon plant was slightly thicker (0.39 to 0.91 for the first year and 0.4 to 1.11 for second year) compared with the first cut. In the first year, sorghum treated with P attained the thickest stems (0.91) and planting of three crops together resulted in thicker sorghum stem. Second year ratoon revealed that SL/R significantly scored the higher value of the SD (1.11cm).Generally, addition of P increased the SD. Leaf area (cm²)

Ratoon plants showed smaller leaf area compared with the last reading of the first crop. Clitoria grown alone (C) produced the largest leaf area (50.17 cm2). Clitoria: Sorghum: Lablab /P/R had the smallest leaf area (24.28 cm2). Inoculation relatively increased the leaf area. Phosphorus addition had no clear effect on the leaf area.

Clitoria ternatea: All readings were significantly different in the two seasons except the second reading of the second season. The leaf area of the 2 Clitoria ranged between 3.43 to 55 cm for the first 2 season and 9.32 to 57.26 cm for the second season (Tables 1a and 1b).

Lablab purpureus: All readings of the two seasons were significantly different except the second and the last reading of the first season. The leaf areas of lablab plant ranged between 13.6 to 167.9 cm2 for the first season and 16.76 to 235.25 cm2 for the second season.

In the first reading of the first season, plants treated with phosphorus or inoculated with Rhizobium were not significantly different and even sole or intercropped treatments did not affect the size of the leaves. Second reading showed an observable increase in the leaf area, sole plants relatively scored the largest leaf area. Increase in leaf area due to addition of phosphorus was observed. Inoculation did not affect Clitoria leaf area.

First reading of the first season revealed L/P/R had the largest leaf area (25.6 cm2) and LCS/P/R had the smallest one (13.6 cm2), the rest of the means were not significantly different. Although there were very large differences between means, there were no significant differences in the second and last readings.

At time of harvest, plant’s leaf area reached the largest size compared with the previous readings. Clitoria: Lablab /R treatment resulted in plants with the largest leaves (55 cm2) whereas C/R had the smallest leaf area (32.27 cm2). Intercropping of three plants resulted in smaller leaves. Effect of phosphorus was not statistically significant.

 

Leaf area in ratoon plants was significantly affected by treatments. Clitoria: Sorghum: Lablab /P/R treatment resulted in the largest leaf area (167.9 cm2) and SL was the smallest one (45.4 cm2). Rhizobium

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inoculation and addition of phosphorus at the same time increased the leaf area in different intercropping treatments.

together with addition of P significantly increased the leaf area of the sorghum. Sorghum grown with lablab relatively gave large leaf area compared to sorghum with Clitoria.

In second season, first reading showed significant difference among treatments. Clitoria: Lablab /R and L/P/R had the largest leaf areas (93.25 and 92.87cm2 respectively) and SL treatment gave the smallest leaf area (16.76 cm²). The effect of intercropping, P and R were not significant in this reading.

In the second season, first and second readings were not significant, but treatment means were highly variable. Intercropping increased the leaf area of sorghum plant in the first two readings, but phosphorus and Rhizobium had no effect. At time of harvest plots planted with two or three crops produced large leaves compared with sole crops. P and R did not increase the leaf area. Second cut revealed significant difference between treatments, P relatively increased the leaf area of sorghum. In general the two combinations intercropping gave larger leaf area.

Second reading revealed significant variation among treatments. The maximum leaf area resulted from L/P/R treatment (216.8 cm²) which was not significantly different from CL and CL/P/R treatments; other treatments were not statistically different in leaf area. At time of harvest plants produced large leaves. Lablab grown with sorghum and treated with P resulted in the largest leaves (235.25 cm²), but this treatment was not significantly different from the rest of the treatments except, SL treatment which produced plants with the smallest leaves (124.29 cm²).

Leaf-to-stem ratio: Leaf to stem ratio decreased with the increasing of plant age in the two seasons (Tables 3a and 3b).

Sorghum sudanense: The leaf area of the plant under study ranged between 2.01 to 136.9 cm² for the first season and 14.07 to 195.35 cm² for the second season. There were significant differences among treatments in the two seasons except, second reading of the first season and first and second reading of the second season. Sorghum planted with Clitoria and sole sorghum (S) produced the largest leaves (6.56 and 6.35 cm², respectively).

Clitoria ternatea : Treatments significantly affected L/S ratio in the two seasons and in all readings of the first crop except the last reading. During the first season the leaf to stem ratio ranged between 0.79 and 7.3, whereas in the second season it ranged between 1.01 and 8.8. In the first reading, generally the two-combination intercropping revealed higher ratios compared with three-combinations. The highest ratio (7.3) was obtained with sole Clitoria not treated, whereas CL/P/R was the lowest one. In most treatments, the ratio increased with the addition of phosphorus. Rhizobium inoculation did not clearly affect the ratio. Moreover, in the second reading the two crops combination and sole crops recorded the highest ratios. The effect of Rhizobium inoculation and phosphorus addition was not significantly different. Ratoon plants gave ratio between1.07 and 2.07. The SC/P/R and C/P/R treatments scored the highest value.

In spite of the lack of significance of the second reading, there was some degree of variation between means. Sorghum intercropped with lablab and treated with P was the best treatment with respect to leaf area (75.2 cm²). There was significant difference in the last reading. Clitoria: Sorghum: Lablab /R treatment produced the largest leaf area (108 cm²) and SC/R gave the smallest leaves (60.4 cm²).

In the second season CL treatment gave the highest ratio in the first reading and the rest of the treatments were not significantly different. In the second reading SC treatment obtained the highest score of 2.9 and SCL/P was the lowest treatment ratio. Third reading did not show any significant difference. Ratoon of second season revealed significant difference among treatments, CL/P/R was the highest one.

Ratoon crops were significantly variable in leaf areas due to the application of different treatments. Unlike most treatments, intercropping of the three crops (LCS) produced plants with larger leaves (206.3 cm²), whereas SL/R, L, LC/P, LC, LC/R and LC/P/R gave smaller leaves.

Second cut revealed significant variation among treatments. Clitoria: Sorghum: Lablab /P/R treatment scored the largest leaf area (136.9 cm²), followed by SCL/P (134.4 cm²). The planting of the three crops

 

115

Agric. Biol. J. N. Am., 2011, 2(1): 109-124

Table 2.a. Effect of intercropping, phosphorus and inoculation on leaf area (cm²) of Clitoria, lablab and sorghum (2005) Treatment Clitoria Lablab st

nd

st

nd

st

1 reading

2 reading

At 1 harvest

At 2 harvest

1 reading

SCL

4.4ab

32.3ab

39.96ab

41.1abc

SC/P/R

4.79ab

27.96ab

38.23ab

39.3abc

L /P/ R

nd

st

nd

2 reading

At 1 harvest

At 2 harvest

25.6a

112.9a

142.3a

85.7ab

20.2ab

122.59a

143.a

101.8

Sorghum nd st 2 At 1 reading harvest

nd

At 2 harvest

4.38ab

53.3a

80.2ab

47.9f

3.38ab

36.7a

75.1ab

113.9abcd 129.4ab

SL

16.2ab

75.2a

120.a

45.5b

4.6ab

40.2a

62.1b

SL /R

16.91ab

76.8a

63a

88.02ab

3.77ab

60.6a

67.6ab

62.6ef

SL/P

16.97ab

73.2a

130.2a

127.3ab

4.59ab

75.2a

70.8ab

121.6abc

SL/P/R

23.72ab

95.7a

1375a

125.1ab

5.69ab

67.7a

96.4ab

106.6abcd

L

23.3b

107a

15.4a

79.6ab

L/P

15.3b

10298a

100.8a

96.6ab

13.6b

92.35a

139.4a

167.9a

17.64ab

97.4a

118.5

117.84ab

S SCL/P/R

4.84ab

20.5b

39.6ab

48.73ab

L/R

6.35a

39.6a

61.7b

116.4abcd

3.28ab

37.1a

93.4ab

136.9a

SCL/R

4.96ab

31.87ab

47.4ab

29.3a

22.20ab

102.6a

85.9a

90.3ab

5.35ab

65.5a

108a

82.2cdef

SCL/P

5.8ab

41.2a

37.82ab

32.7bc

17.9ab

100.97a

148.2a

102.6ab

4.82ab

49.2a

94.4ab

134.4ab

C/P

4.22ab

36.6ab

38.22ab

44.97abc

C/P/R

3.43b

26.5ab

4.02ab

42.6abc

SC

4.62.ab

22.97b

39.3ab

46.8abc

6.56a

53.8a

75.3ab

88.5bcdef

SC/R

3.96ab

21.94b

37.7ab

47.94abc

3.3ab

44.1a

77.7ab

48.3f

SC/P

4.01ab

30.4ab

38.8ab

47.1bc

2.01b

378a

60.4a

72.3edf

4.93ab

49.5a

61.2b

79.7cdeg

C

4.52ab

36.03ab

45.7ab

52.5a

CL/P

3.94ab

29.9ab

37.1b

36.abc

20.3ab

100.6

125.a

89.5ab

CL

4.36ab

31.98ab

39.85ab

44.7abc

19.14ab

98.1a

132.a

142.3ab

S/P

C/R

3.66b

28.6ab

32.27b

41.9abc

CL/R

5.2ab

31.16ab

55a

46.9abc

19.3ab

102.1a

142.9a

68ab

CL/P/R

5.95ab

31.4ab

39.67ab

47abc

17.89ab

107.7a

112.2

118.5ab

SE±

0.16

1.04

1.08

1.1

0.36

4.4

6.2

6.6

CV

23.8 23.9 18.7 17.6 22.6 30.8 35.4 43.2 Means with the same letter (s) within each column are not significantly different at 0.05 level using Duncan’s Multiple Range Test. Legend: C = Clitoria, L = lablab, S = sorghum, P = phosphors, R = Rhizobium

 

st

1 reading

116

0.3

3

3.4

3.7

42.9

44.4

28.6

25.5

Agric. Biol. J. N. Am., 2011, 2(1): 109-124

Table 2.b. Effect of intercropping, phosphorus and inoculation on leaf area of Clitoria, lablab and sorghum (2006) Clitoria Treatment

st

nd

Lablab st

nd

st

nd

Sorghum st

nd

1 reading

2 reading

At 1 harvest

At 2 harvest

1 reading

2 reading

At 1 harvest

92.87a

216.87a

199.74ab

17.1b

SCL

22.02ab

46.37

57.25ab

44.94abcd

71.79abc

143.87b

199.16ab

SC/P/R

15.10abc

47.7a

58.82ab

48.78ab

SL

16.76c

130.61b

124.29b

SL /R

34.69abc

137.84b

SL/P

44.75abc

140.02b

SL/P/R

34.61abc

L

31.14

L/P

L /P/ R

At 2 harvest

13.97abc

49.2a

52.84b

43.91abcd

L/R

st

nd

At 1 harvest

At 2 harvest

206.3a

47.29a

152.31a

185.48a

125.72cdef

33.38a

141.52a

111.9b

173.17b

153.04c

14.07a

88.93a

100.87b

143.75cd

172.15ab

108.8e

14.88a

127.86a

97.65b

134.67

235.25g

139.05cd

14.27a

118.8a

115.29b

120.64def

108.59b

129.4b

146.53c

29.25a

121.8a

117.19 b

195.35a

121.9b

199.36ab

109.11

41.19abc

132.55b

185.6ab

176.35b

22.14bc

136.48b

158.44ab

181.11b

45.32abc

139b

190.18ab

129.87de

31.3a

121.2a

108.98b

102.444gf

26.27a

136.36a

131.46ab

135.44cd

SCL/R

18.62abc

49.59

52.84a

43.91abcd

69.59abc

131.7b

152.33ab

121.3ed

22.93a

144.02s

122.64b

84.55g

SCL/P

18.62abc

49.59a

50.55b

34.33f

68.57abc

180.2ab

179.34

135.37cd

32.53

163.98

131.42

126.59

C/P

13.3

40.96a

45b

45b

C/P/R

9.32c

41.96a

86.2a

44.45abcd

SC

12.54bc

41.67a

49.62b

41.59abcdf

14.87a

116.05a

124.76b

123.77cdef

19.22a

132.21a

151.07ab

108.93ef

39.68cdef

18.64a

104.07a

93.91b

140.33

17.32a

91.42a

111.89b

145.57c

SC/R

21.1abc

52.2a

49.23b

SC/P

13.53abc

40.88a

45.29b

S/P C

15.88abc

48.07a

46.65b

50.17a

CL/P

14.10abc

43.8a

57.26ab

36.99ef

40.99abc

130.87b

155.76ab

104.71e

CL

15.18abc

40.06a

47.74b

39.13

54.96ac

162.07ab

161.93ab

105.8 e

C/R

11.93bc

40.64a

54.34ab

41.79bdce

CL/R

19.91abc

50.3a

54.46ab

42.0bcde

93.25a

130.77b

201.51ab

112.48

CL/P/R

25.11a

54.17

54.60ab

46.91abc

88.03ab

180.4ab

184.74

114.15e

SE±

0.87

1.3

2.43

0.56

4.91

5.5

6.76

1.58

3.39

6.2

4.66

1.92

CV

14.5

19.5

31.5

9.3

59.51

26.2

26.5

7.86

88.8

31.7

24.8

9.29

Means with the same letter (s) within each column are not significantly different at 0.05 level using Duncan’s Multiple Range Test. Legend: C = Clitoria, L = lablab, S = sorghum, P = phosphors, R = Rhizobium

 

nd

2 reading

S SCL/P/R

st

1 reading

117

Agric. Biol. J. N. Am., 2011, 2(1): 109-124

Lablab purpureus: Treatments were significantly different in the two seasons, except in the first reading of the first season. Leaf to stem ratio ranged between 0.45 and 6.7 in the first season and 0.95 to 6.9 in the second season. Although the first reading in the first season was not significant, some variations found among the means in which CL got the highest ratio. Addition of phosphorus to the plants slightly increased the ratio. The three-combination intercropped treatments gained the lesser ratios to some extent compared with soles and two intercrops. Means were significantly different in the second reading. Lablab plants treated with phosphorus (L/P) gave the highest ratio of 3.16. Lablab: Clitoria / Rhizobium and LC/P/R were significantly lower than L/P plots. At the time of harvest L/R significantly recorded the highest ratio, whereas the LCS/P was the lowest treatment. The average leaf to stem ratio of the first season ratoon was similar to the average of the last reading. Lablab /P showed the highest ratio (2.07) and LC/R combination ranked the lowest.

different in ratoon, the ratio was not obviously affected by inoculation and intercropping, but it was increased in most cases by addition of phosphorus. Nodulation: This parameter was measured after 6 weeks from planting and at the time of harvest. Clitoria ternatea Number of nodules: In the first season, nodule counts were significantly increased (P < 0.05) with the addition of phosphorus in the first reading, in which Clitoria intercropped with sorghum gained the highest number (16.44) but at the time of harvesting nodule number were not affected by neither phosphorus nor intercropping in spite of its significant difference (Table 4). In general, at the time of harvesting the nodule number tended to decrease. In the second reading, significant difference appeared among treatments, sole Clitoria plants obtained the highest number of nodules per plant (11.44). In the second season number of nodules per plant increased and the treatments were not significantly different in the first reading, but sole Clitoria plant got the highest number

In the second season, leaf to stem ratio of lablab in all readings was significantly affected by treatments. Not like other readings, in the first reading, the intercropping of the three crops (LSC/P) gave the higher ratio, otherwise soles and two intercropped plots obtained the best results. Phosphorus addition in most cases increased the ratio.

In the last reading there was significant difference among treatments. The total number of nodules decreased, the treatment (SCL/P/R) gave the highest nodulation with an average of 47.67 nodules per plant. Generally phosphorus had more effect on nodule number than Rhizobium inoculation in the same treatments.

Clitoria: Lablab /P/R revealed the higher figure (3.54) followed by LCS and LS was the lower ratio in the second reading, other treatments were not significantly different. At time of harvest lablab grown alone obtained the highest ratio of 1.74, phosphorus and Rhizobium were not clearly affecting the ratio. Ratoon plants were significantly varied with treatments, LC/P/R (2.7) was the best treatment, addition of phosphorus and Rhizobium were not affecting the ratio.

In both seasons, the average number of nodules per plant decreased with the progresses of plant growth towards maturity. Nodules number decreased from 6.52 to 3.32 in the first season and from 34.81 to 16.53 in the second season. Weight of nodules (gram): In the first season, weight of nodules was not significantly different between treatments in the first reading, but there were slight differences between means where the treatment (SCL/P/R) gained the heaviest weight (Table 5). In the second reading, treatments were significantly different in weight of nodules; sole Clitoria weighed the heaviest nodules with the mean of 0.6 g per nodules per plant. In the second season nodule weight did not show any significant variation in the first reading, but at the time of harvest it revealed significant difference among treatment means. Treatment C/P/R, gained the heaviest weight. The average nodule weight per plant ranged between 0.083 to 0.158 and 0.40 to 0.74 g per plant for the first and second season, respectively.

Sorghum sudanense: First season did not reveal any significant variation, but in the second season all readings showed significant differences among treatments. Leaf to stem ratio ranged between 0.67 to 3.46 for the first season and 0.45 to 24.1 for the second season. In the second, SC treatment gave the highest ratio of 24.1 in the first reading, the rest of the treatments were statistically not significant. In second reading, addition of phosphorus increased the ratio; intercropping and Rhizobium did not increase the ratio. At the time of harvest SC treatment gave the highest ratio. Although, treatments were significantly

 

118

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Table 3.a. Effect of intercropping, phosphorus and inoculation on leaf to stem ratio of Clitoria, lablab and sorghum (2005)

nd

At 2 harvest

Sorghum st nd At 1 2 harvest reading

st

nd

1 reading

At 2 harvest 1.48abcd 0.77de

Lablab st nd At 1 2 harvest reading 1.52bc 2.30ab 1.70bc

2.90ab

st

nd

Clitoria st nd At 1 2 harvest reading

st

1 reading

Treatment

1 reading 4.05a

At 2 harvest

5.22a

1.57abcdef

1.29a

2.08ab

3.3ab

SCL

2.07a

1.32a

2.04ab

4

SC/P/R

L /P/ R

0.87a

0.66a

1.08a

2.6a

1.23a

0.92

1.83a

2.33

1.27a

0.75

0.77a

1.67a

0.70de

1.90abc

1.83ab

4.18a

SL

1.23a

1.07a

1.44a

3.36

1.77abc

2.93a

2.23ab

5.83a

SL /R

1.20a

0.59a

0.83a

1.53a

1.17abcde

1.72bc

2.51ab

6a

SL/P

1.10a

0.57a

1.11a

1.53a

1.33

1.53bc

1.94

4.4a

SL/P/R

1.7abc

1.43bc

2.25ab

5.03a

L

2.07a

2.21abc

3.16a

4.5a

L/P

1.49bc

1.87

4.78a

1.23a

1.28a

1.01a

1.58a

0.8

1.20a

1.33a

1.63a

0.63de 1.3ab

1.2c

2.55ab

5.11a

0.67a

0.64a

1.38a

1.57a

1.03bcde

1.60bc

1.99ab

1.10a

0.62a

1.82a

2a

0.93bcde

1.16c

2.26ab

S 1.83abc

1.23a

0.93b

4ab

SCL/P/R

4.11

1.3cdef

1.36a

1.88ab

2.3ab

SCL/R

5.8a

1.67abcde

1.097a

1.66ab

5.8ab

SCL/P

1.47bcdef

1.26a

1.84ab

2.7ab

C/P

2.07a

1.046

1.77ab

3.1ab

C/P/R

L/R

0.97

0.79a

.072a

1.5a

0.67

0.68a

1.47a

3.33a

1.23ef

1.25a

2.98a

4.5ab

SC

0.9a

1.35a

1.35a

3a

1.8abcd

1.053a

1.87ab

5.8ab

SC/R

1.2a

1.30a

1.41a

1.8a

1.07f

0.91a

1.75

5.3ab

SC/P

2ab

1.03a

2.05ab

7.3a

C

1.45bcde

1.025a

1.4ab

4.5ab

CL/P

1.53abcdef

1.21a

1.97

5ab

CL

1.87abc

1.46a

1.49

7ab

C/R

S/P

0.45e

1.71bc

1.50b

5a

1.56abcdef

1.28a

1.75ab

5ab

CL/R

1.05bcde

2.53ab

1.54b

5.5a

1.25def

0.79a

1.39ab

2b

CL/P/R

0.06

0.07

0.09

0.22

0.03

0.04

0.12

0.3

SE±

32.9 63.8 65.1 51.9 33.69 28.95 30.02 30.7 14.7 Means with the same letter (s) within each column are not significantly different at 0.05 level using Duncan’s Multiple Range Test. Legend: C = Clitoria, L = lablab, S = sorghum, P = phosphors, R = Rhizobium

26.4

40

50.6

CV

0.05

 

0.09

0.13

0.17

119

Agric. Biol. J. N. Am., 2011, 2(1): 109-124

Table 3.b. Effect of intercropping, phosphorus and inoculation on leaf to stem ratio of Clitoria, lablab and sorghum (2006) nd

At 2 harvest

Sorghum st nd At 1 2 harvest reading

Lablab st

nd

st

1 reading

At 2 harvest

At 1 harvest

1.9bc

1.15abcdef

2.51bcde

3.1b

1.14de

1.023bcdef

3.51a

3.7b

st

nd

2

reading

1 reading

nd

At 2 harvest

Clitoria st nd At 1 2 harvest reading

st

1 reading

Treatment L /P/ R

1.64bcdef

0.95a

2.2abc

5.6b

SCL

2.17ab

0.85a

2.13abc

3.65b

SC/P/R

0.8d

0.41a

0.77ab

18.8b

1.04bcd

0.68ab

1.96ab

5.48b

1.18abc

0.92ab

0.53ab

20.9b

1.1de

1.56abc

1.73e

4.2ab

SL

1.34a

0.93ab

1.14ab

12.6b

1.95bc

1.6ab

2.6abcdef

4.6ab

SL /R

0.97bcd

0.88ab

0.87ab

6.9b

1.04e

1.63ab

2.77abcd

3.7b

SL/P

1.01bcd

0.61ab

1.51ab

4.6b

1.63bcd

1.53abcde

2.14edc

3.4

SL/P/R

1.67bcd

1.74a

1.8de

4.3ab

L

4.7ab

L/P

2.07b 1.27ab

0.706

0.69b

5.5b

1.01

0.76

2.04a

2.4b

0.89dfe

2.9abc

S 1.9bc

1.097bcdf

2.1cde

3.6b

2.0bc

1.47abcde

2.71abcde

3.9b

1.9abcd

1.07a

1.13de

3.4b

SCL/P/R

1.97abcd

3.8b

SCL/R SCL/P

L/R

1.08abcd

0.76ab

1.74ab

5.5b

1.34cde

0.95cdef

2.37bcde

3.01b

1.5egdf

0.99a

1.0bcd

0.57

1.4ab

20.13b

1.3de

1.24abcdef

2cde

6.9a

1.47def

1.03a

1.01d

3.2b

1.24gf

1.1a

1.92abcd

3.2b

C/P

2.06abc

1.1a

1.8bde

3.5b

C/P/R

0.97bcd

1.06a

0.86ab

74.1a

1.02g

1.2a

2.9a

5.2b

SC

1.04bcd

0.57ab

1.5ab

10.8b

1.7abcde

1.08a

2.4ab

4.2b

SC/R

0.9cd

0.55ab

1.14ab

3.07b

1.07g

1.02a

1.73bcd

3.9b

SC/P

0.93

0.45b

0.72ab

5.9b

S/P 1.816abcd

1.22a

1.57bcd

4.6b

C CL/P

1.15de

0.64f

1.98cde

3.9b

1.48defg

1.15

2.2abc

4.4b

0.95e

0.79f

1.81de

4.4ab

1.32egf

1.16a

1.43bcd

12.8a

CL

1.9abcd

1.1a

1.83abcd

2.7b

C/R

2.1b

1.17abcdef

3.15ab

3.9b

2.03abcd

1.35a

2.04abcd

4.2b

CL/R

2.7a

1.077abcde

3.54a

3.3b

2.27a

1.35a

2.13abc

3.2b

CL/P/R

0.039

0.05

0.8

2.21

0.04

0.04

0.08

0.57

SE±

12.8 41.3 55.7 139.4 16.9 27.7 21.04 36.62 17.7 Means with the same letter (s) within each column are not significantly different at 0.05 level using Duncan’s Multiple Range Test. Legend: C = Clitoria, L = lablab, S = sorghum, P = phosphors, R = Rhizobium

22.8

28.7

88

CV

0.2

 

0.05

0.1

9.1

120

Agric. Biol. J. N. Am., 2011, 2(1): 109-124

Prussic acid (ppm): Hydrocyanic acid (HCN) was measured at harvesting time for both first and second crops (Table 6). Intercropping and Rhizobium inoculation did not significantly affect the amount of HCN in sorghum plant tissues in the two seasons.

Lablab purpureus Number of nodules: In 2005 season treatments were significantly different in number of nodules in the first reading. Nodules count ranged between 35.45 to 4.89 per plant (Table 4). After 6 weeks from planting (first reading) lablab intercropped with Clitoria scored the highest number, whereas lablab treated with phosphorus and Rhizobium gained the lowest number. At the time of harvest, treatments were significantly different. The total nodule number per plant decreased in a range of 17.45 to 2.22.The treatment (LC/P/R) recorded the highest number of 17.45 per plant, and L/P scored the lowest number In 2006 season (second season) nodule number was significantly different in the first reading and nodule numbers ranged between 39.67 to 10.7. Sole lablab treated with phosphorus gave the highest number of nodules (39.67), whereas L/P/R scored 10.7 nodules per plant. In the last reading, although there were large differences between means, treatments were not significantly different . Clitoria: Lablab /P/R scored the highest number of nodules (35.7) and SCL/R scored the lowest number (6.7). In general, nodule numbers decreased at the time of harvest, and they ranged between 6.7 to 35.7 with an average of 18.75 nodules per plant compared with 24.13 nodules per plant in the first reading.

In the first season, there were significant differences in HCN both first crop and ratoon. In first crop, sorghum plant in SL treatment produced the highest amount of HCN (187.02) whereas SC/P recorded the lowest value (133.1). The sole sorghum treated with phosphorus contained lesser amount of HCN than untreated plant of about 25 ppm. In ratoon plants, SC/R treatment resulted in sorghum plant with the highest amount of HCN (162.1), whereas SCL/P obtained the lowest value (138.4). nd In the second season first crop and ratoon (2 cut) showed significant difference among treatments. The higher amount (ppm) of HCN was observed in sorghum plants not treated with phosphorus. In the first crop SL recorded the highest value of156.19 ppm and the lowest HCN (132.3 ppm) was recorded in S/P treatment. Intercropping did not affect the amount of HCN. In ratoon, HCN of sorghum plants was significantly affected by addition of phosphorus. Sorghum in SCL combination produced the highest HCN (159.8) whereas sorghum plant in (SL/P/R) combinations produced the lowest value (130.9).

Weight of nodules (g): Lablab nodule weights were significantly different (P < 0.0001) with intercropping, phosphorus and Rhizobium inoculation in the first season in both readings (Table 5). The average nodule weight per plant was 0.783 g for the first reading and 0.775 g for the second reading. In the first reading, C/L combination resulted in the heaviest weight (3 g), means of SCL/P/R and L/R treatments were slightly higher than the rest of means and S/L combination recorded the lowest nodule weight. At time of harvest, SCL/P treatments showed the heaviest weight (3.5 g) the remaining treatments were not significantly different.

DISCUSSION Stem thickness was significantly affected by intercropping and addition of phosphorus. Sole crops were pronounced to produce forage with thicker stems in the first crop, but intercropped plants treated with P developed thicker stems during the second cut (ratoon). In the first case (sole crop), phosphorus probably had a role in cell division and in the other metabolic processes of the plant which resulted in increase of stem diameter. Plant population also affected stem thickness. In the second cut (ratoon), due to decrease in ratoon plant population, stem diameter increased due to the less competition.

In the second season, there were significant differences in both readings. The average nodule weight was 1.88 g for the first reading and 1.41 g per plant for the second reading. In 2005, the heaviest weight was recorded for the L/P treatment (4.83 g) followed by CL/P/R treatment. At time of harvest L/P/R, SCL, SL/R, SL/P/R, L, SCL/P/R, LR and CL/P were not significantly different in nodule weight. In general plots not treated with phosphorus gave lightest nodules.

 

Prussic acid: The poisonous substance (HCN) in sorghum significantly decreased with P treatment and this is in agreement with Abusuwar (2005) who stated that addition of phosphorus and organic fertilizer decreased the HCN concentration. On the other hand, untreated plants accumulated high amount of HCN in the tissues. Nodulation: In general Clitoria in intercropping treated with P and inoculated with Rhizobium gained high number and weight of nodules. This could be

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due to the concentration of P in nodules is higher than any other parts of plant (Sa and Israel, 1991) and in most cases phosphorus increased nodulation, and by doing so increased nitrogen resulted in increasing of crude protein content (Hague and Mohamed, 1985). Under severe P deficiency condition in some legume, nodule formation is completely stopped (Almeida, et al. 2000). Phosphorus deficiency limits nodule development and growth more than that of the other organs (Drevon and Hartwig, 1997).

Some unexpected results have been found such as untreated sole plants produced high number and weight of nodule which indicated that experimental field may contain some endogenous Rhizobium strains of lablab and Clitoria. Lablab planted with Clitoria treated with P and R revealed more nodulation which may justify the importance of Rhizobium strain in the inoculation process. Phosphorus plays a vital role in energy transfer, metabolic regulation, phospholipids, DNA and RNA (Plaxton et al., 1989).

Table 4 Effect of intercropping, phosphorus and inoculation on nodule No. of Clitoria and lablab 1st season 2nd season Clitoria Lablab Clitoria Lablab Treatment At 6th week 6th week At harvest 6th week At harvest 6th week At harvest harvest L /P/ R 4.89b 8.22aabcd 10.7b 17.3a SCL 8.98ab 3.33ab 6.11b 14.22abc 41.67 a 18.33 ab 16ab 17.3a SC/P/R 8.21ab 2.22ab 31.67 a 10.67 b SL 6.0b 16.67cbd 23.33ab 14.3a SL /R 13.67b 678ab 23ab 24.7a SL/P 7.67b 2.22d 19.ab 24.7 SL/P/R 12.78 6.66bcd 12.7ab 21a L 9.53b 12.67abcd 28.7ab 27a L/P 16.33b 4.45cd 39.67a 19a SCL/P/R 11.49ab 2.00ab 7.17b 7abcd 45a 40.67a 28ab 23.7a L/R 14.33b 9abcd 35.33ab 22.a SCL/R 0.44b 089ab 11.11b 3.89cd 45.33a 11.67b 15.33ab 6.7a SCL/P 4.11ab 2.22b 8.33b 3.33d 28.67a 14.7a 31ab 11.3 C/P 11.34ab 1.44 44.67a 21ab C/P/R 5.89ab 6.11ab 33.33a 16.89ab SC 2.78b 7.78ab 33.67 13.33b SC/R 3.22b 00b 32.67 8.33 SC/P 16.44a 1.44ab 36.33 1.33b C 1.92b 11.4a 4.67a 12.67b CL/P 3 1.45ab 8b 4.99cd 42.33a 0.9ab 29.33ab 20.7a CL 6.33ab 2.22ab 35.45a 3.22d 19.33 21.33ab 23.3ab 14.7a C/R 6.33ab 3.00ab 39.67a 12.2b CL/R 7.33ab 2.7ab 16.00b 9.28abcd 15a 17ab 12ab 7.3a CL/P/R 6.67ab 4.83ab 14.67b 17.45a 20.0a 18.ab 38.67ab 35.7a SE± 0.97 0.81 1.36 0.8 3.6 1.9 2.04 2.8 CV 102 168 78.4 67.8 71.6 80.9 58.8 102.6 Means with the same letter (s) within each column are not significantly different at 0.05 level using Duncan’s Multiple Range Test. Legend: C = Clitoria, L = lablab, S = sorghum, P = phosphors, R = Rhizobium

 

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Table 5 Effect of intercropping, phosphorus and inoculation on nodule weight (g) of Clitoria and lablab st

nd

1 season Clitoria

Treatment

2

Lablab

season

Clitoria

Lablab

th

th

6 week

At harvest

SCL

0.33a

0.033b

SC/P/R

0.113a

0.003b

L /P/ R

th

6 week

At harvest

0.36b

0.89b

0.38b

0.22b

6 week

At harvest

0.60a

1ab

0.40a

0.31b

th

6 week

At harvest

1.45bc

1.53ab

1.53bc

1.22ab

SL

0.15b

0.58b

1.33c

0.8b

SL /R

0.55b

0.82b

1.37c

1.27ab

SL/P

0.46b

0.18b

1.87bc

1b

SL/P/R

1.22b

0.74b

1.2c

1.97ab

L

0.67b

0.62b

1.73bc

3.87a

0.71

0.33b

1.72ab

1.06b

L/P SCL/P/R

0.24a

0.03b

1.66ab

0.84b

SCL/R

0.003a

0.03b

0.23b

SCL/P

0.03a

0.12b

0.27b

L/R

0.37a

1.07ab

0.44b

0.38a

0.5b

3.5a

0.70a

0.45b

C/P

0.36a

0.033

0.67a

0.7b

C/P/R

0.136

0.04b

0.47a

2.76a 0.35b

SC

0.03a

0.14a

0.27a

SC/R

0.02a

00b

0.37a

0.93

SC/P

0.11a

0.007

0.50a

0.32

4.83a

1.87ab

1.9bc

2.07ab

1.86bc

0.4ab

0.87c

0.67b

1.47

0.77b

C

0.28a

0.60a

0.37a

0.38b

CL/P

0.12a

0.007

0.5

0.9b

2.13bc

1.55ab

1.47c

0.9b

CL

0.23a

0.37

0.14a

0.67ab

C/R

0.15a

0.14b

0.30a

0.47b

CL/R

0.14a

0.04b

0.18b

0.97b

0.13a

0.7b

0.87c

1.55ab

CL/P/R

0.24a

0.08b

0.48b

0.56b

0.2

0.33b

4.12ab

0.9b

SE±

0.03

0.04

0.14

0.19

0.06

0.15

0.19

0.2

CV 148 304 121.4 171.2 102.3 136.5 71.6 97.8 Means with the same letter (s) within each column are not significantly different at 0.05 level using Duncan’s Multiple Range Test. Legend: C = Clitoria, L = lablab, S = sorghum, P = phosphors, R = Rhizobium

 

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Table 6 Effect of intercropping, phosphorus and inoculation on HCN (PPM) of sorghum plant st 1 season Treatment st nd st 2 harvest 1 harvest At 1 harvest

2

nd

season At 2

nd

harvest

L /P/ R SCL

157.9abc

153.1c

154.4a

159.8a

SC/P/R

151.7b

139.5d

137.03d

136.9de

SL

187.02a

150.9c

156.19a

153.04bc

SL /R

152b

153.3c

144.5bc

153.04abc

SL/P

151.2b

139.4d

133.6d

134.1de

SL/P/R

135.5b

136.1d

132.5d

130.9

S

158.3ab

160.7ab

144.9bcd

159.1ab

SCL/P/R

146.6b

138.7d

134.65d

134.4de

SCL/R

151.3b

155.5bc

1493.4b

151.9c

SCL/P

150.3b

138.4d

134.6cd

131.9de

L L/P

L/R

C/P C/P/R SC

157.9ab

156.5bc

149.3ba

156.5abc

SC/R

155.2b

162.1a

144.8bc

157.9abc

SC/P

133.1b

139.9d

133.2d

138.2d

S/P

133.3b

139.6d

132.3d

134.7de

2.56

0.49

0.62

0.58

C CL/P CL C/R CL/R CL/P/R SE±

CV 10.95 2.14 2.9 2.6 Means with the same letter (s) within each column are not significantly different at 0.05 level using Duncan’s Multiple Range Test. Legend: C = Clitoria, L = lablab, S = sorghum, P = phosphors, R = Rhizobium REFERENCES Hague, L.A. and Mohamed, M.A. (1985). Phosphorus st management with special references to forage legumes of Abusuwar, A.O. (2005). Forage production in Sudan. 1 ed. U of K. Sub-Saharan Africa. Potential of forage legumes in farming Sudan (in Arabic) system of Sub-Saharan Africa. Proceeding of workshop held Almeida, J.P.F.; Hartwig, U.A.; Frehner, M.; Nosberger, J. and at ILCA, Addis abba Ethiopia. Luscher, A. (2000). Evidence that P deficiency induces N Herridge, D.F. (2008). Inoculation technology of legumes. Chapter feedback regulation of symbiotic N 2 fixation in white clover (4), p 77-115. In Dilworth, M. J. James, E. K, Sprent, J.I. and (Trifolium repen L). Journal of Experimental Botany, 51: 1289Newton, W.E. (eds.) (2008). Nitrogen-fixing Leguminous 1297. Symbioses. Nitrogen Fixation: Orgins, Application. Volume 7. British Pharmacopoeia (1980). Analytical Pharmaceutical Practical. Published by Sprinker. 402 pages London. Her Majesty's Stationary Office. P885. Plaxton, W. C, Duff, S. M. G, Moorhead, G. B. G and Lefebvre. D. Drevon, J.J and Hartwig, U.A (1997). Phosphorus deficiency (1989). Phosphate starvation inducible ‘bypass’ of denylate increases the argon-induced decline of nitrogenase activity in and phosphate dependent glycolytic enzymes in Brassica soybean and alfalfa. Planta. 201, 463-469. nigra suspension cells. Plant Physiology, 90: 1275-1278. Graham, P.H. (2008). Ecological of the root-nodule bacteria of Sa, T. M and Israel, D. W (1991). Energy status and functioning of legumes. Chapter (2), p. 23-43. In Dilworth, M. J, James, E. K, P deficient Soybean nodules. Plant Physiology, 97:928-935. Sprent, J. I and Newton, W.E. (eds.) (2008). Nitrogen-fixing Shambat Meteorological Station (2008). Annual report Leguminous Symbioses. Nitrogen Fixation: Orgins, Application. Volume 7. Published by Sprinker. 402 pages.

 

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