Agroforestry Systems 17:43--51, 1992. © 1992 Kluwer Academic Publishers. Printed in the Netherlands.

W h e a t cult ivat ion in assoc ia t ion with Acacia nilotica (L.) Wil ld ex. De l . field bund plantat ion -- a case s tudy

K. K. SHARMA Division of Social Forestry, Forest Research Institute, P.O. New Forest, Dehra Dun-248006, India

Key words: agroforestry, Acacia nilotica var. jaquemontii, wheat, bund plantation, crop yield

Abstract. The paper presents the results of a case study conducted to find out the influence of single row bund plantation of Acacia nilotica var. juquemontii on the growth and yield of associated wheat crop under irrigated conditions in Haryana, India. The indications are that the tree line does affect all crop parameters like height growth, shoot numbers, ear length, grain number and grain yield in the vicinity of trees upto 4 m distance from the tree line and establishes that as the distance from the tree line increases the growth and yield of wheat crop also improves. The effect on wheat crop was found more pronounced in the plots laid out towards the middle of the tree line as compared to plots towards the outer border.

Introduction

Trees are grown on agriculture field bunds, combined with agriculture crops for augmenting biomass production per unit area. In return the farmer gets the cash benefits as also the return in the form of fuelwood, fodder etc. Many tree species like Eucalyptus hybrid, Dalbergia sissoo, Populus deltoides, Acacia nilotica, Syzygium cumini and Prosopis cineraria are preferred by farmers in northern India. In the present study influence of A. nilotica trees grown on field bunds on associated wheat crop has been determined.

Material and methods

The study was conducted during 1986 in the village of Bakarpur, Naraingarh (Haryana). The soil of the field was sandy loam to loam with good surface drainage. The mean annual rainfall varied from 1000--1200 mm, mostly received from July to September. Nine year old A. nilotica var. jaquemontii bund plantation was grown in East-West direction along the northern bound- ary of the field along with wheat variety HD 2009. The other three sides of the field had no trees and were treated as open side border. The area of the field was 0.4 ha. The wheat field was flood irrigated five times during the growing season. The effect of trees on wheat crop was estimated in terms of crop parameters like height growth, shoot number, ear length, grain yield and number of grains per kg. The trees were measured for their top height, diameter at breast height, clean bole length and crown width.

Sample plots of 1 m e were laid in a line running perpendicular to the tree

44

line and replicated five times (Annex I). the lines were spaced at 10 m, 20 m, 30 m from either side of the border towards the centre of the tree line. In all, 36 sample plots were laid out at various distances perpendicular to the tree line upto a distance of 23 m from the tree line and grouped into four distance treatments viz; (T1) < 4 m, (T2) 4 m to 8 m, (T3) 8 m to 15 m, and (T4) above 15 m.

From the data thus collected, various crop parameters were analysed by using the analysis of variance technique. The number of observations in each treatment varies, hence a t test was applied for comparing the treatment means. In this estimation, the observation beyond 15 m (T4) was considered as control for comparing the results of other treatments.

For the estimation of the extent of variation in yield due to distance, the sample plot distances from the tree line and also from side open boundaries of the field were taken into account and a functional relationship was established using the sample plot yield data.

Results

Under agroforestry, agricultural crops and trees interact with each other without much change in the cultivation practices. In this regard, the present study examines the effect of single row of Acacia nilotica trees on wheat crop.

Data presented in Table 1 showed no significant differences in shoot height and shoot number. However, a gradual increase in crop height and shoot number from the tree line to the farthest plots (T4) was evident. The ear length was noted significantly higher (9.18 cm) at T3 treatment as compared to others. The A. nilotica tree line has shown significant effect on associated crop yield at different distances from the tree line. The grain yield increased as the distance from the tree line increased. Grain yield was found significantly less (42%) upto 4 m and gradually increased beyond 4 m distance. However, the yield was found significantly higher (22.83 q/ha) beyond 15 m (T4). To find out the adverse effect trend in the close vicinity of trees, mean grain yield was calculated as under:

Distance from tree line Mean grain yield per m z (m) (kg)

Below 1.0 0.103 1 to 2 0.159 2 to 3 0.144 3 to 4 0.144 4 to 6 0.145 6 to 8 0.165 8 to 15 0.175 Above 15 0.228

Tab

le 1

. E

ffec

t of

A.

nilo

tica

tre

e li

ne o

n a

ssoc

iate

d w

heat

cro

p.

Dis

tanc

e fr

om

tre

e li

ne

Wh

eat

crop

par

amet

ers

Bel

ow 4

m

4.0

m--

8.0

m

8.0

m--

15.

0 m

A

bo

ve

15.0

m

as i

nflu

ence

d by

tre

e li

ne

(T1)

(T

2)

(T3)

(T

4)

Bar

dia

gra

m

Pla

nt h

eigh

t (c

m)

per

m 2

68

.21

71.8

6 S

hoot

nu

mb

er p

er m

2

132.

50

130.

00

Ear

len

gth

(cm

) pe

r m

2

8.29

8.

50

No.

of

grai

ns p

er k

g 3

19

8 b

2

92

4

Gra

in y

ield

(q/

ha)

13.2

4 15

.24

(42.

00)

(33.

24)

70.7

4 13

2.89

9.

18 b

28

95

17.5

1 (2

3.30

)

71.6

3 a

154.

80 a

8.63

28

63

22.8

3 c

(00)

T3

9.18

T

3

31

98

T

4

22.8

3

T4

8.

63

T4

2

92

4

T3

17

.51

T2

8.

50

T2

28

95

T

2

15.2

4

T1

8.29

T

1 2

86

3

T1

13.2

4

a =

Sta

nds

for

no

t si

gnif

ican

t.

b =

Sta

nds

sign

ific

ant a

t 5%

lev

el.

c =

Sta

nds

sign

ific

ant

at 0

.1%

lev

el.

( )

= F

igur

es i

n p

aren

thes

is i

ndic

ate

per

cent

red

ucti

on.

4~

t.da

46

The above data indicate that the grain yield upto 4 m at various distances was found overlapping showing no definite trend. Beyond 4 m the yield improves with the increase in distance from the tree line. The number of grains per kg were found significantly more (3198 per kg) upto 4 m distance (T1) as compared to other distance treatments T2, T3, T4, there being no significant difference between treatments. This reduction in grain yield was due to poor growth of wheat plants near the tree line as is evident from the data on plant height, shoot number, ear length (Table 1). The loss in grain yield was found upto 15 m distance from the tree line. Thus, the total affected area due to the tree line (55 m) worked out to 825 m 2 (Annex II). The wheat production in this area was calculated using the difference in mean yield in plots upto 15 m distance and the mean yield in plots beyond 15 m distance from the tree line. The reduced yield in the affected area (825 m 2) was found to be 61.82 kg per 55 m tree line (one sided) i.e. 1.12 q per 100 m tree line.

Estimated yield. The regression of sample plot mean yield data over distance (m) was carried out and the following regression equation was derived.

1 x 2 - - = 5.3004 + 0.19461 × - - y xl

R 2 -- 0.2585702

R = 0.5084979

An estimate of yield for different distances was calculated and a regression curve drawn as depicted in Fig. 1.

The fitted regression equation has a correlation coefficient R -- 0.51 which is significant at one % level. The curve shows that wheat grain yield was comparatively more (varies from 14 q/ha at 1.0 m to 18.5 q/ha at 22.0 m) towards side open borders (10 m distance) as compared to plots laid towards the centre of the tree line, grain yield varies from 11.0 q/ha at 1.0 m to 18.25 q/ha at 22.0 m (20 m) and from 9.0 q/ha at 1.0 m to 18.0 q/ha at 22.0 m (30 m). The estimated yield curve indicates that the decreasing trend in grain yield was found upto 12 m distance from the tree line and beyond that the yield becomes uniform. This reveals that the wheat production is greatly influenced by the trees in the centre portion of the tree line.

Tree measurements

A. nilotica trees were growing at 4.75 m spacing in a 55 m tree line. The tree line comprised 13 trees. The mean values calculated for top height, diameter

47

20

18

14

lal

z

10

~ _ ~ o o.-.---o- x I ()Orn) X2 (2Ore) x 3 (3Ore)

f

l i , I I I I I I I I

I 2 Z, 6 e 10 12 IL 16 IB 20 2

DISTANCE FROM TREE LINE (m)

Fig. 1. Effect of A. nilotica tree line on wheat grain yield.

at breast height, clean bole length, crown width were found as 7.73 m, 20.49 cm, 2.55 m and 3.70 m, respectively. For the estimation of total wood production for all the trees, the following regression equation was considered

131. V ---- 0.002080 + 0.411526 DZH

The total wood production so calculated was found 1.866 m 3 for 13 trees per 55 m tree line, thus 3.387 m 3 for 23.6 trees per 100 m tree line.

48

Discussion

Based on the overall influence of A. nilotica tree line on wheat production, the indications are that as the distance from the tree line increases, the crop parameters also show a progressive growth trend in the order of T1 < T2 < T3 < T4. The results in the present study are in conformity with earlier reports [1] and [4] where similar indications were also reported. The tree line has significantly affected the ear length, grain size and grain yield near the tree line upto 4 m distance. The data in (T1) revealed that the grain size has been considerably affected resulting in a higher number of grains near the tree line. A closer look at the results indicates that all crop parame- ters were always numerically lowest at below 4 m (T1) and higher values were noted at later distances 4 m to 8 m (T2), 8 m to 15 m (T3) and above 15 m (T4). The farmer had not practiced any pruning of trees and the average crown width of trees recorded was 3.70 m which indicates that upto 4 m distance from the tree line the area remains completely under shade. The reduction in yield was 42% (Table 1) in the vicinity of trees upto 4 m distance (T1) which was under complete shade in comparison to the crop plants away (T4) and open to sunshine. The regression curves indicate that effect on yield upto 12 m distance and beyond becomes normal. It has been reported [2] that with 9 to 11-year-old A. nilotica trees the production of wheat is reduced by 40 to 49% upto a distance of 7 m, which is also the trend of the present study. The affected area due to tree line was about 825 m 2 and the total loss in grain yield from this area was determined to 61.82 kg which is insignificant and can be compensated from the income received from the trees. The total wood production was found as 1.866 m 3 for 13 trees per 55 tree line. Considering the additional income in the form of timber, fuelwood and fodder from A. nilotica trees, its plantation on field bunds is desirable.

Acknowledgements

The author wishes to record his sincere thanks to Dr. R. V. Singh, Director General, I.C.F.R.E. for suggesting the problem and constant guidance at various stages of the investigation. Sincere thanks are due to Dr. Parvej Ahmed, Dy. Conservator of Forests (R&T), Haryana, for providing facilities in the field and to shri D. S. Rawat, Scientist 'SD' for help in statistical analysis.

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Annexure II

AFFECTED AREA DUE TO TREE LINE

5 D

AFFECTED AREA

NORMAL AREA

Lu

% ~n

NORMAL AREA \~ • .... : . . . : . . . . : - . . : . . . - . . . , . . . , . . . . . , . . . . . . . . . . . . . .

i , . . . . . . . - . - . . . ~ : . , : . . , . - : , ' . - . : . ; , : . : . . : ' ~ . , - . , . - . . - : : ~ : .

• . . . . . . . : , . . . . . . . " . . . . . . " . : . . . . , . m . ' ~ . : . , , : . . . . . . , . . •

' " ~"'" " ' " "" D " " " " ' : : ' , ' ' " ' " " " ~" -..;'...: ..:.,~,AFFECTE AREA " , ' , . . ' : ' . . . . . " ' . . . ' . : w

TREE LINE

References

1. Aijun Prasad, Subbayan R, Sam M and Ramnath (1983) Preliminary studies on the effect of different tree species on yield of field crops under rainfed condition in vertisols of Ballary. Nat. Syrup. on Watershed Management for Increased Productivity in Red and Black Soils, Memeo, pp 1--6

51

2. Dhillon MS, Surjeet Singh, Atwal AS and Dhillon GS (1984) Agrisilvicultural practices: effect of Dalbergia sissoo and Acacia nilotica on the yield of adjoining crops. Indian J Eco111(2): 249--253

3. Sharma, RP and Jain RC (1977) General standard volume tables for Babul (Acacia nilotica ssp indica), Indian For Rec (NS) For Man and Mensuration, Vol I No 4, FRI, Dehra dun

4. Shrivastava AK, Verma B and Narain P (1983) A case study for farm forestry in south- eastern Rajasthan. Nat. Symp. on Watershed management for increased Productivity in Red and Black soils, Memeo, pp 1--4