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Evaluation of plant-animal relationships on different range-pastures in western Rajasthan, India

by RANCHOR B. DAS *

(*) Ranchor B. Das, Agrostologist, Central Arid Zone Research Institute, Jodhpur, India.


Introduction
References


SUMMARY

Approximately 21.8 million hectares of sub-tropical semi-arid and arid rangelands in India have 10.58 million standard animal units. The present feed and fodder resources are deficient by 36.2 per cent as maintenance ration and by 80 per cent as production ration. Various studies have been carried out indicating relative palatability of important range grass species which are the components of Dichanthium-Cenchrus-Lasiurus grassland type. Experimental studies on assessing appropriate use factor as represented by height-weight relationship, relative palatability, nutritional status, relative compatibility and trend of plant succession under the impact of animal grazing on range vegetation have revealed interesting results evaluating the role of major grass species in a sub-tropical rangeland from the point of view of animal production. Experimental data on these studies have been tabulated to bring out animal-plant interaction as it exists in Western Rajasthan in India. The dynamic approach embracing the principles of range ecology have been followed in each case and the experimental work under sub-tropical semi-arid conditions in India brings out the potentialities which exist and findings which would have wider application under comparable conditions.

Introduction

Approximately 218.1 thousand square kilometers of land in India under sub-tropical semi-arid and arid conditions are spread over the states of Rajasthan, Gujrat, Haryana and Madhaya Pradesh (1974). The animal population in the region is 21.5 million, of which cattle, buffalo, sheep, goats, camels and other animals comprise 7.40, 6.55, 4.27, 0.65 and 0.27 million respectively. In other words there are 10.58 million of standard adult animal units in the region to be maintained on range-pasture resources.

Evaluating the actual feed and fodder requirements of the above animal population, 27.2 million tons of dry forage is required for maintenance only (7 k per adult animal unit per day on a year-long basis). However, from the currently existing resources including cultivable waste, fallow fields, rangelands and also crop residue, etc., it is estimated that feed available is 17.3 million tons. Thus, there is an overall shortage of 36.2 per cent feed in the region. Considering a productive nutritious ration, the deficit would be nearly 80 per cent of the total requirements. It would be amply evident from the above that there exists a total imbalance between range grazing resources and animal population in the semi-arid and arid sub-tropical regions of India, resulting in low animal productivity directly influenced by insufficient and low nutrient feed, where erratic and unpredictable rainfall received is between 100 mm and 400 mm.

Further, continued improper land use has completely destroyed the original vegetation cover, and the majority of grazing lands are put under plough for cropping, which is practiced on all types and classes of lands, including shifting sands and dune slopes having as much as 30 to 40 per cent dip. In addition, heavy and continued grazing by all types and kinds of animals has caused widespread soil erosion, dune formation and loss of soil fertility, bringing in its trail misery and poverty to an already poor population who continually struggle to recover from one famine and loss of valuable livestock under prolonged drought only to enter another famine of the same devastating nature, thus remaining caught in a vicious circle.

In the recent past, there has been a general awakening at various levels among land and stock owners regarding the need for an application of advanced technology to improve the deteriorated and depleted range pastures, in order to obtain a sustained level of production through management practices based on accepted principles of range ecology. The following principles may be listed as important:

1) The application of the "proper use" factor for key species in the range.

2) The concept of relative potentialities of individual species in a range grassland community from the point of view of animal grazing capacity and utilization.

3) The concept of plan succession in range vegetation influenced by grazing of different classes and types of animals on the range.

In this paper a correlation is brought forth between factors influencing ecology or range vegetation and its management, utilization, and development under the impact of animal grazing (appraisal of animal/plant interaction).

Relative palatability of range species

The ranges and grasslands in sub-tropical semi-arid and arid regions in India have been recognised as having vegetation cover called Dichanthium-Cenchrus-Lasiurus type (Dabadgao, 1960). The most important component grass species of this community are namely, Dichanthium annulatum, Cenchrus ciliaris, Cenchrus setigerus, Panicum antidotale, Lasiurus sindicus, Eleusine compressa, Dactyloctenium sindicum, Digitaria adscendens, Eremopogon foveolatus, Sehima servosum, Bothriochloa pertusa, Heteropogon contortus, Chrysopogon fulvus,, Iseilema laxum and others.

For the purpose of suitable and scientific range management the key species in the rangeland ought to be maintained at the highest level of production from both the qualitative and the quantitative point of view by following the principle of appropriate degree of utilization. For developing such standards of utilization of the key species in a range pastureland, there is a need to have quick, easy and accurate indices or guides so that under proper use both major objectives may be achieved.

The literature on the methods of measuring utilization has been reviewed by Pechance and Pickford (1937), Dasman (1948) and Heady (1950). It may be stated that the method evolved by Lommasson and Jensen (1938, 1942, 1943), which was also accepted by Campbell (1937, 1942), was considered simple, accurate and rapid. The method consists in determining the percentage reduction in height due to use factor and converting it into weight by reference to previously prepared height-weight tables or charts referring to key range species.

Regression studies were made on the data obtained regarding percentage height clipped (X) and percentage weight removed (Y), and by fitting the orthogonal polynomial as indicated by Fisher (1950). Thus, quadratic curves of the form represented by equation Y=A+BX²+CX² were fitted separately for the range grasses Lasiurus sindicus, Cenchrus ciliaris, C. setigerus, Panicum antidotale and Dichanthium annulatum while studied by Das et al. (1964) under Western Rajasthan conditions, and for Sehima nervosum, Bothriochloa pertusa, Heteropogon contortus, Dichanthium annulatum, Chrysopogon fulvus and Iseilema Laxum by Shankarnarayan et al. (1969) under Jhansi conditions, as detailed below:

Rajasthan

Lasiurus sindicus

Y = 0.136 - 0.005

X + 0.241 X2

Cenchrus ciliaris

Y = 2.610 - 2.137

X + 0.329 X2

Cenchrus setigerus

Y = 2.069 - 1.695

X + 0.327 X2

Panicum antidotale

Y = 2.437 - 1.728

X + 0.311 X2

Dichanthium annulatum

Y = 1.097 - 1.186

X + 0.312 X2

Jhansi

Sehima nervosum

Y = 2.4490 + 0.157

X + 0.00784 X2

Dichanthium annulatum

Y = 1.4055 + 0.2738

X + 0.00697 X2

Bothriochloa pertusa

Y = 1.1415 + 0.2796

X + 0.007061 X2

Heteropogon contortus

Y = 0.3120 + 5.022

X + 0.004808 X2

Chrysopogon fulvus

Y = 0.5465 + 0.5439

X + 0.004150 X2

Iseilema laxum

Y = 1.1595 + 0.4107

X + 0.005613 X2

It would be observed from the fitted curves that in the case of range species at Jodhpur (Rajasthan) like Lasiurus sindicus, Cenchrus ciliaris, Panicum antidotale, Dichanthium annulatum and Cenchrus setigerus, when 20 per cent forage is grazed 45, 58, 54 and 61 per cent height is removed. Again, stating in the same order, 40 per cent utilization is achieved when 63, 73, 71, 75 and 85 per cent height is grazed or clipped.

However, fitted curves for the studies done at Jhansi also show that the weight is not evenly distributed throughout the height of the grass plants. For instance, 20 per cent of the weight from the top is clipped or grazed when 38, 37, 36, 32, 30 and 29 per cent height from the top is clipped, in the case of Sehima nervosum, Bothriochloa pertusa, Dichanthium annulatum, Iseilema laxum, Heteropogon contortus and Chrysopogon fulvus, respectively.

Further, it is pointed out that height-weight tables are not universally applicable and ought to be prepared separately for even the same species under different range habitats: Das et al. (1964).

Relative Palatability of Range Species

Considering the fact that the relative palatability of a range species determines its intensity of use by the grazing livestock, observations were recorded by Dabadgao et al. (1962) for five of the most important species of arid Western Rajasthan; and palatability rating was done comparing them with the grass Dichanthium annulatum, which was taken as 100 per cent palatable. The details of these observations are in Table 1 below.

Nutritional status of important range grasses

Das et al. (1964) have explained on the basis of average nutritional value of different grasses that in natural range plants, nutrients are at a low level and therefore, animal production derived from such ranges is also low. However, it was observed that application of chemical fertilizers containing N.P.K., where each nutrient was applied are the rate of 22 k per hectare, increased the crude protein contents in the case of Cenchrus ciliaris, Panicum antidotale, Lasiurus sindicus and Cenchrus setigerus by order or 58, 26, 82 and 108 per cent, respectively, over control. Nutritional values for these grasses studied by Mandal et al. (1968) achieved significant results.

Table 1 - Relative palatability of six arid zone range grasses (for cattle)


Pasture stage

Pre-flowering

Flowering stage

Ripe stage

Deap ripe stage

Dichanthium annulatum

100.0

100.0

100.0

100.0

100.0

Cenchrus ciliaris

51.9

169.7

52.8

125.0

266.7

Cenchrus setigerus

43.9

55.6

32.4

97.1

216.7

Lasiurus sindicus

43.2

31.5

37.9

109.7

125.0

Panicum antidotale

19.0

30.8

10.7

38.5

16.7

Panicum turgidum

49.7

14.0

31.2

59.4

33.3

Table 2 - Average nutritional values of some range grasses

Range Plant Species

Percentage of dry matter yield

Total available digestible protein kilo/hectare

Crude protein

Phosphorus

Digestible protein

Cenchrus ciliaris

12.82

0.517

8.60

522.15

Cenchrus setigerus

8.77

0.602

4.89

168.87

Panicum antidotale

12.24

0.489

8.07

667.92

Dichanthium annulatum

5.05

0.482

1.48

19.05

Lasiurus sindicus

9.05

0.557

5.15

287.31

The average nutritional values for important arid and semi-arid zone range grasses are produced in Table 2.

It would appear that average crude and digestible protein in the case of Cenchrus ciliaris is highest; while phosphorus contents in the case of C. setigerus is more than in other species, and the lowest is that of Dichanthium annulatum. The available digestible protein for the species Panicum antidotale has been found to be highest. However, since this species is stemmy it would be desirable to graze it more frequently to keep it down to the leafy stage.

Evaluation of relative compatibility of range species

The knowledge of ecological behaviour of the key species in a semi-arid or arid range land is very important. The relative performance of each of the individual species with respect to growth, forage yield, grazing capacity and persistency is an indication of its adaptability to the range under specific conditions of soil and climate. The potentialities of range grasses like Lasiurus sindicus, Cenchrus ciliaris, C. setigerus, Panicum antidotale and Dichanthium annulatum have been studied on two contrasting ecological habitats, one on sandy soil at Jodhpur and the other at Pali on sandy loam soils.

At each place four major species were seeded on an equal area, and initially comparable sheep flocks were allowed to graze for a period of three years. Each year observations were recorded on forage yield, grazing capacity and reaction to grazing (Table 3). With the change of soil and climate the evaluation of grazing potentialities and livestock production of each of the species was found to be significantly varying. On sandy loam soil more animal production was evidenced, in comparison to sandy habitat, which has low moisture retentivity. It should also be clear from the table that ranges having greater cover of these perennial species would be able to carry more livestock.

Table 3 - Comparative evaluation of range grass species on sandy and sandy loam sites
(average of 3 years grazing)

Species

On sandy soils (Jodhpur)

On sandy loam soils (Pali)

Variations

Av. No. of sheep days

Av. forage product kilo/ha

Av. grazing capacity

Av. No. sheep days

Av. forage product kilo/ha

Av. grazing capacity

No. of sheep days

Forage product kilo/ha

Grazing capacity per ha

Cenchrus ciliaris

661

629.2

4.46

1,115

1,496.6

7.53

454

867.4

3.07

Cenchrus setigerus

321

353.6

2.53

889

1137.4

6.04

568

783.8

3.51

Panicum antidotale

606

880.2

4.06

737

1,621

4.90

131

840.8

0.84

Lasiurus sindicus

1,049

1,276.8

6.92

-

-

-

-

-

-

Dichanthium annulatum

-

-

-

1,022

1,331.3

6.86

-

-

-

Animal plant interaction on rocky range

Studying the principles of range pasture ecology Weaver and Darland (1948), Weaver and Tomanek (1951), Tomanek (1948), Clark et al. (1947) and Campbell (1931) have indicated the influence of animal grazing on range vegetation and the trends in plant succession along with forage production under different habitats. Albertson et al. (1953) have recommended light grazing of deteriorated rangelands for its positive advantages in terms of better animal performance and progressive increase in forage production, and at the same time for its economic importance when compared with even moderate and heavy stocking of the ranges.

Studies on range regeneration under the impact of animal grazing were carried out on 51 hectares of a rocky range near Jodhpur. Again, it is a universally accepted fact that an animal/plant system on a grazing range is complex and is influenced by several ecological factors. Considering the range/plant/community status as a reference axis, the following critical conceptual points would emerge.

(a) Range/plant/community status directly affects type and amount of forage produced and available.

(b) The quality and quantity of forage produced and available directly affect the animal production.

(c) The type and kind of animal directly affect range/plant/community.

(d) Thus, the impact of animal on quality and quantity of forage produced and available is indirect via the effect on range/plant/community status.

Keeping these concepts in view studies were conducted which revealed interesting data, as detailed in tables 4 and 5 below. Young heifers grazed lightly; and the grazing capacity was pre-determined on the basis of the formula, total no. of animal days on range =

It would be evident from the data in the tables that a significant increase in quality and quantity of forage production was achieved on the range at the same time that animal gains were also recorded, even when grazing was practiced during the post-monsoon period.

Table 4 - Evaluation of effect of grazing on plant cover and forage yield on range vegetation after controlled grazing for 3 years

Composition

Percentage plant cover

Forage yield (kilo/ha)

Variation after 3 years

Before grazing

After 3 years grazing

Before grazing

After 3 years grazing

% of plant cover

Forage yield in kilo/ha

I. Edible species


A. Grasses







(i) Perennial species

8.7

14.82

362.5

659.8

6.12

297.3

(ii) Annual species

4.8

7.42

28.3

29.8

2.62

1.5


B. Non-grasses and fortes

1.5

1.2

Traces

1.8.

- 0.29

1.8

II. Non-edible species

1.6

0.33

9.7

3.1

- 1.27

- 6.6

Total

16.6

23.78

400.5

694.5

7.18

294.0

Table 5 - The average monthly body-weight of heifers in kilograms

Grazing period

Initial

Nov.

Dec.

Jan.

Feb.

March

April

May

June

1st year

81.8

-

-

81.8

88.1

93.0

90.9

91.5

92.14

2nd year

81.05

84.07

85.2

87.1

87.9

90.5

95.5

-

-

The increase in cover of perennials as well as annuals gave enhanced forage production. Table 5 shows increase in average animal gains.

Thus, animals gained on the average 10.34 kilograms during their first year of range grazing, when forage was completely overripe and seed had fallen; while in the second year the average gains were 14.45 kilograms over the initial weight.

Range utilization and animal production

Studies were conducted on a fair type of range vegetation dominated by a Zizyphus-Eleusine-Aristida community. Here, three different types of livestock, namely steers, wethers and goats, were grazed for a period of three years. The results obtained are given in table 6 below:

Table 6 - Results of percentage utilization and increase in body weights

Particulars

Types of animals

Steers

Wethers

Goats

Percentage utilization of range

61.4

63.9

59.9

Percentage increase of body weights

111.2

59.6

96.4

It would be evident from the table that for an approximately comparable degree of utilization of range pastures, the response in terms of animal production has significantly varied with the type of animal. The percentage increase in weight of steers is nearly twice as much as that of wethers, while that of goats closely follows that of steers. The results also indicate that given a similar rate of utilization of primary production, the secondary production in terms of meat per hectare is highest when steers are grazed; goats give less, and sheep the least of all.

References

ALBERTSON (F.W.) REIGEL (A.) and LAUNCHBAUGHT Jr (J.L.), 1953. Ecology 34: 1-20.

Anonymous, 1974. Nat. Comm. on Agric. Govt. of India. New Delhi. Page 1.

CAMPBELL (R.S.), 1931. J. Agri. Res. 43: 1027-1051.

CAMPBELL (R.H.), 1937. Ecology Vol. 18: 528-532.

CAMPBELL (R.H.), 1942. U.S. Forest. Serv. pp. 3 (mimeo).

CLARK (S.E.), TISDALE (E.W.) and SKOGLUND (N.A.), 1947. Domm. Dept. Agri. Tech. Bull. 46: 54.

DABADGAO (P.M.), 1960. Proc. 18th International Grassland Cong. paper 94/5.

DABADGAO (P.M.) and MURWAHA (S.P.), 1962. Ind. Jour. Agron. 7: 1: 86-90.

DAS (R.B.) and GUPTA (B.S.), 1964. Ann. Arid Zone Vol. 2 2: 185-187.

DAS (R.B.) and BHIMAYA (C.P.), 1964. Proc. Symp. Problems of Indian Arid Zone (1964). 1971. Pages 222-226.

DAS (R.B.), DABADGAO (P.M.), DEBRONY (R.), 1964. J. Brit. Grassland Soc. Vol. 19: 4: 429433.

DAS (R.B.), BHIMAYA (C.P.) and BHATI (G.N.), 1965. J Soil and Water Cons. of India. Vol. 13: 1: 33-42.

DASMANN (W.P.), 1948. Calif. Fish. Game 34: 119-207.

FISHER (R.A.), 1950. Oliver and Boyd. Edinburgh.

HEADY (H.F.), 1950. Ecol. Monog. 20: 55-81.

LOMMASSON (T.) and JENSEN (C.), 1938. Science 78: 226-444.

LOMMASSON (T.) and JENSEN (C.), 1942. U.S. Forest Serv. Region 1. pp. 16 (Mimeo).

LOMMASSON (T.) and JENSEN (C.), 1943. J. For. Vol. 41: 93.

MANDAL (R.C.) and CHAKRAVARTY (A.K.), 1968. Ann. of Arid Zone. Vol. 7: 1: 56-61.

PECHANCE (J.F.) and PICKFORD (G.D.), 1937. J. Agri. Res. Vol. 54: 763-765.

TOMANEK (G.W.), 1948. Trans. Kans. Acad. Sci. 5: 171-196.

WEAVER (J.E.) and DARLAND (R.W.), 1948. Ecology Vol. 29: 1: 1-29.

WEAVER (J.E.) and TOMANEK (G.W.), 1951. Univ. Nebr. Cons. and Surv. Div. Bull. 31: 82.


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