Desertification of Western Maharashtra: Causes and possible solutions. I. Comparative growth of eight tree species

Forest Ecology and Management, 16 { 1986) 243-251 Elsevier Science Publishers B.V., Amsterdam - - Printed in The Netherlands

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Desertification of Western Maharashtra: Causes and Possible Solutions. I. C o m p a r a t i v e G r o w t h of Eight Tree Species B.V. NIMBKAR, N. NIMBKAR and N. ZENDE

Nimbhar Agricultural Research Institute, P.O. Box 23, Phaltan, Maharashtra 415523 (India) (Accepted 7 May 1986)

ABSTRACT Nimbkar, B.V., Nimbkar, N. and Zende, N., 1986. Desertification of Western Maharashtra: Causes and possible solutions. I. Comparative growth of eight tree species. For. Ecol. Manage., 16: 243-251. In the low rainfalltract of Western Maharashtra, the degraded area that can be called a desert in the making is 2.28 million ha out of a total of 5.7 million ha or 4 0 % of the area. The main causes of this desertification are overcultivation coupled with deforestation and overgrazing. T h e problem is made more acute by the increasing h u m a n and animal population, and the fact that rainfall is undependable and of high intensity. The trend of desertificationcan be reversed by (a) closing the area to grazing and uncontrolled wood cutting, (b) implementation of time-tested soil and water conservation measures and (c) large scale planting of suitable forage grasses and legumes as well as arid zone species of trees.The main research thrust of the trialswith promising species of trees was to determine their suitabilityto wastelands and to investigate methods of establishing them rapidly and economically. Thus the effect of fertilizationand spacing was examined for the following eight tree species:Acacia albida,A. niloticavat. cupressi[ormis,A. niloticavar. indica, Albizia lebbek, Cassia siamea, Dalbergia sissoo, Leucaena leucocephala, Melia azedarach and Prosopis juliflora.The two spacings used were 5 X 0.6 m and 3 X 1 m and the three fertilizerdoses were 0:0:0, 50:50:50 and 100:100:100 kg N:P2Os:K20 per ha. A factorial design with nine plant selections,three fertilizertreatments, two spacings and three replicateswas used. A total of seven irrigations were applied from October 1983 to February 1984. At 15 months of age the average basal stem diameters of L. leucocephala and M. azedarach were significantly superior to all the other species. The average plant height of L. leucocephala, at 2.38 m, was superior to all other species. The use of fertilizerled to significant improvements in performance; however, there was littledifference between using a dose of 50 kg ha-i or 100 kg ha-I. A n interaction was found to exist between the species and spacings. L. leucocephala and M. azedarach showed better performance at the spacing of 5 X 0.6 m and D. sissooand P. julifloraperformed better at 3 >< 1 m. C. siamea at 6 2 % had the lowest survival rate.

INTRODUCTION The National Commissionon Agriculture (1976a) has classifiedthe different rainfall zones in each Indian state. Zone I, where our institute is located,

244 TABLE 1 Weather data from Phaltan station (1983-1984) Year

1983 1984

Month

October November December January February March April May June July August September October November December

Rainfall (mm)

39.50 2.75 4.75 30.50 0.55 7.00 32.40 123.40 0.20 284.30 158.60 -

Rainy days

3 1 1 3 1 3 7 10 1 8 7 -

Average air temperature (°C) Max.

Min.

31.1 29.3 28.7 30.3 31.8 36.8 38.9 40.1 33.2 30.2 29.9 30.7 32.2 31.5 31.6

20.7 12.1 13.1 12.4 15.4 18.8 21.1 21.8 22.0 21.2 20.6 20.1 19.7 13.5 12.9

Average pan evaporation (ram/day)

5.76 5.44 4.13 5.26 6.71 8.84 10.91 12.99 7.60 5.65 6.77 6.16 5.19 4.96 4.70

has less t h a n 50 m m o f rainfall p e r m o n t h d u r i n g seven m o n t h s o f t h e year, between 50 a n d 100 m m d u r i n g f o u r m o n t h s of t h e y e a r a n d o n l y d u r i n g Sept e m b e r is the rainfall b e t w e e n 100 a n d 200 mm. E v e n this rainfall varies g r e a t l y from y e a r to year, as can be seen f r o m t h e 1983-1984 d a t a ( T a b l e 1 ). D u r i n g 1984, t h e r e were n i n e m o n t h s w i t h less t h a n 50 m m o f rainfall p e r m o n t h , two m o n t h s with rainfall b e t w e e n 100 a n d 200 m m p e r m o n t h a n d in S e p t e m b e r the rainfall e x c e e d e d 200 m m . T h e total area in W e s t e r n I n d i a falling u n d e r this zone is 13.3 million ha, out of which 5.3 million h a were w a s t e l a n d in 1974 ( N C A , 1976a). M a h a r a s h tra state has 40% o f its 5.7 million h a located in zone I, a l r e a d y d e g r a d e d a n d u n p r o d u c t i v e ( B h u m b l a a n d K h a r e , 1982). ' T h e initial d e g r a d a t i o n o f t h e l a n d in this zone is due to t h e c u l t i v a t i o n o f field crops irrespective o f t h e l a n d q u a l i t y or sufficiency of rainfall. Soils t h a t are not r e t e n t i v e a n d w h i c h are on slopes are p l o u g h e d a n d sown, r e s u l t i n g in poor yields a n d severe erosion. T h e m a j o r cause of severe erosion is v e r y h e a v y rainfall d u r i n g a p e r i o d o f a few hours. M o r e t h a n 25 cm h a s fallen in 24 h o u r s in m o s t p a r t s o f t h e c o u n t r y a t one t i m e or a n o t h e r ( N C A , 1976a, sec. 13.2.9). Once the land has b e e n e r o d e d b y s h e e t erosion to a level w h e r e c r o p s are no longer productive, it is left to r e g e n e r a t e w h a t grass it can. D a b a d g h a o a n d S h a n k a r n a r a y a n (1973) s u r v e y e d t h e grasses in a s i t u a t i o n similar to ours, a flat grassland site, h e a v i l y g r a z e d u n t i l 1945 a n d since t h e n g r a z e d o n l y to a

245

limited extent by sheep. According to local information it had a pure stand of

Aristida spp. in 1954, now replaced by Lophopogon tridentatus to an extent of 65%. The shrubs found in this southern, thorn-type forest were Acacia leucophloea, Cassia auriculata, Zizyphus mauritiana and Acacia nilotica. The total plant cover was, however, only 11.3%. The pressure on this type of grassland is great, as three to four times as many cattle are grazed per ha than the optimum recommended. Various commissions from 1893 onwards have pointed out that the replacement of grazing by grass cutting is the only solution to this problem (NCA, 1976b, p. 133). In spite of these recommendations, conditions are steadily getting worse. Between 1956 and 1972 the number of animals grazed in forests increased by 52%, though the livestock population increased by only 18% to 355 million ( NCA, 1976b, p. 133). In the past, a major approach to soil conservation had been the construction of contour bunds (A bund is also called a levee, embankment, dike or causeway; where a bank of earth is thrown up from a ditch in order to form a barrier). A recent survey has shown that the effect of bunding is actually negative, due to stagnation of water behind the bund (Shankarnarayan and Shankar, 1984). Personal experience has shown that bunds that are not properly constructed or maintained are often breached, causing severe gully erosion. Preliminary work at our institute has shown that construction of dead level contour furrows at suitable intervals is a far better method of conserving soil and water. A small catchment thus treated resulted in silt-free collection as compared to muddy water in the catchment treated with conventional bunds. For the conservation of water it also seems best to construct small reservoirs and re-use the runoff. This is estimated to be 85-90% of the total rainfall in prevailing shallow soil conditions. Our major failure has been with the establishment of pastures. Seeding of various improved grassland species was not successful, although the planting of setts of Stylosanthes hamata and Cenchrus ciliaris was quite successful. Data will be collected in October 1985 as to the survival of the pastures. Burley (1982) has emphasized the need to compare the survival, growth, yield and managerial characteristics of as wide a range of tree species and populations as possible. The selection of species for preliminary trials explained in this paper was based on seed availability and the recommendations of the forestry department of the Government of Maharashtra. Eucalyptus tereticornis, Casuarina equisetifolia and Azadirachta indica were not included in the experiments, as relatively more data are available on their performance. Multipurpose trees are the focus of a great deal of current research in both agriculture and forestry. In particular, trees which can fix nitrogen biologically are the subject of increased research, because of their enviable ability to be self-sufficient for their nitrogen requirements in low fertility soils. Among the different tree species tested on a sloping, eroded, mountainous

246

wasteland near Pune in M a h a r a s h t r a , with a rainfall of about 440 m m per year from June to October, the best performance was shown by Leucaena leucocephala. Except Eucalyptus hybrid and Sesbania grandiflora which m a t c h e d its performance, none of the other species tested appeared to be promising (Relwani et al., 1986). Desai and Patil (1986) evaluated the comparative performance of seven forage and fuel producing tree species at Rahuri in Maharashtra. Observations on 10-year-old trees indicated superior performance with a high degree of adaptability of Hardwickia binata followed by Acacia tortilis for fuelwood production. Nerkar (1984) raised a trial plantation of ten species over an area of 5 ha in a rocky soil in the Yavatmal district of M a h a r a s h t r a state in India. After eight waterings, Dalbergia sissoo had the highest survival rate with 96% and Sesbania aegyptica the greatest average height of 195 cm at the age of nine months. A field trial was established during the second week of October 1983 to assess the effect of spacing and fertilizer application on the growth and survival rate of eight tree species. All the species except Melia azedarach and Cassia siamea have been reported to fix atmospheric nitrogen (Halliday, 1984). MATERIALS AND METHODS

The experimental site is situated at the village of Vinchurni in the Satara district, 6 km south of Phaltan. The soil type is a degraded vertisol, the characteristic soil of wastelands in this area. The soil depth varied from 7 to 35 cm. The eight tree species used were as follows: Acacia albida, Acacia nilotica var. cupressiformis, Acacia nilotica var. indica, Albizia lebbek, Cassia siamea, Dalbergia sissoo, Leucaena leucocephala (Salvador type), Melia azedarach and

Prosopis juliflora. The influence of fertilizers and spacings on these eight species was examined in a randomized complete block, split-split-plot design with tree selections (9) as main treatments, fertilizer t r e a t m e n t s ( 3 ) as sub-plots and spacings ( 2 ) as sub-sub plots. Three replications were used. The data were analyzed as a 9 X 3 × 2 factorial (while there were eight botanical species, A. nilotica had two subspecies, bringing to nine the n u m b e r of plant selections examined). The three fertilizer levels were 0:0:0, 50:50:50, and 100:100:100 kg ha -1 of N:P20~:K20. The two spacings used were 5 X 0.6 m and 3 X 1 m, which left the per plant area constant at 3 m 2. The plot size was 150 m 2 (15 × 10 m) with 48 plants per plot for the 5 × 0.6 m spacing and 50 plants per plot for the 3 X 1 m spacing. The seedlings were raised in polybags, 20 cm high and 10 cm in diameter and transplanted three m o n t h s later into pits large enough to hold the soil ball. Weed control was carried out only during 1983 by two harrowings. There did

247

not appear to be any border effect during the first year, as each plant had adequate space for growth. The temperature, rainfall and pan evaporation data for the period under study are shown in Table 1. The area received 684 mm of rainfall from October 1983 to December 1984. In addition to water from the rainfall, the seedlings received seven irrigations, each of about 800-1000 m 3per ha, during the period from October 12, 1983 to February 29, 1984. The irrigations were applied by flow method and the interval between irrigations was about 15 days. The source of water was the stream flowing nearby during the post-monsoon period and irrigation was stopped when the stream-flow dried up. A compound fertilizer mixture (19:19:19) was applied in two doses to give the fertilizer level for each treatment. The first one-third dose giving 0:0:0, 17:17:17 and 33:33:33 kg ha-1 of N:P20~:K20 was applied on January 8, 1984, followed by three irrigations. The remaining two-third dose giving 0:0:0, 33:33:33 and 67:67:67 kg ha -1 of N:P20~:K20 was applied on 15 August 1984. It was followed by 443 mm rainfall and one irrigation applied during the last week of December, 1984. During the first fortnight of January 1985, about 15 months after transplanting, plant mortality and measurements of plant height and basal stem diameter were recorded. RESULTS AND DISCUSSION

Influence of fertilizer Leucaena leucocephala showed significantly greater height and basal diameter than Melia azedarach (Table 2 ). The latter species is non nitrogen-fixing, but surprisingly did not show a greater response to fertilizer application than the nitrogen fixing species. In fact Leucaena gave the highest response to fertilizer application of all the species tested. Leucaena seedlings are often slow growing and as a consequence the establishment phase can be prolonged. Jones et al. (1983) found nitrogen fertilization to have the greatest effect on all plant measurements. This they attributed to the low nitrogen supplying ability of the lithosol used and also the slow nodulation, a characteristic which has often been observed with Leucaena. Phosphorus also seems to be a critical nutrient for Leucaena. On soils with low P, Leucaena may be impossible to grow without the application of fertilizer. In an experiment by Hegde (1983), Leucaena seeds were sown in pots containing soil with five different levels of phosphorus - - 0.002, 0.008, 0.032, 0.128 and 0.512 mg per ml solution - - and were provided with adequate amounts of N, K and Ca. After three months, the seedlings of the first two levels of P had only grown 8 and 20 cm high respectively, whereas the plants grown at 0.032 mg P

2.49 1.19 0.70 0.79 0.87 0.64 0.59 0.51 0.62 0.93

0:0:0 2.92 1.44 1.10 1.08 0.98 0.70 0.80 0.88 0.80 1.19

50:50:50 2.86 1.44 1.30 1.20 1.07 0.78 0.90 0.93 0.81 1.25

100:100:100 2.76 1.36 1.03 1.02 0.97 0.71 0.76 0.77 0.74

2.85 2.08 0.99 1.94 1.42 1.07 0.93 1.24 1.02 1.50

0:0:0 3.51 2.79 1.34 2.34 1.55 1.27 1.22 1.86 1.32 1.91

50:50:50 3.54 2.64 1.52 2.67 1.68 1.33 1.34 1.93 1.33 2.00

100:100:100

N:P20~:K20 (in kg h a - ~)

N:P~Os:K20 (in kg h a -~ ) Mean

Basal stem diameter b ( c m )

Stem height" ( m )

3.30 2.50 1.28 2.32 1.55 1.22 1.16 1.68 1.22

Mean

"Stem height ( m ) : species, LSD ~<0.01 = 0.23 m; fertilizers, LSD ~<0.01 = 0.13 m; t r e a t m e n t , LSD ~<0.01 = 0.40 m. bBasal stem diameter ( c m ) : species, LSD ~<0.01 = 0.31 cm; fertilizer, LSD ~<0.01 --0.18 cm; t r e a t m e n t , LSD ~<0.01 = 0.53 cm. c% Survival: species, LSD ~<0.01 = 12.2%.

Mean

L. leucocephala M. azedarach P. juliflora C. siamea D. sissoo A. albida A. nilotiott var. cupressiformis A. lebbek A. nilotica var. indica

Species

Comparative performance of eight different tree species at three fertilizer levels

TABLE 2

91.8 83.4 93.1 61.9 88.3 93.8 90.0 85.4 85.7

% Survival ¢

b~ Oo

249 TABLE 3 Comparative performance of eight different tree species at two spacings Species

Stem height a ( m ) Spacing

L. leucocephala M. azedarach P. juliflora C. siamea D. sissoo A. albida A. nilotica vat. cupressi[ormis A. lebbek A. nilotica vat. indiea Mean

Basal stem diameterb (cm) Mean

5x0.6 m

3)<1 m

2.88 1.51 0.90 1.05 0.78 0.74 0.85 0.85 0.71 1.14

2.64 1.21 1.16 1.00 1.17 0.68 0.67 0.70 0.77 1.11

2.76 1.36 1.03 1.02 0.97 0.71 0.76 0.77 0.74

Spacing

Mean

5×0.6 m

3X1 m

3.37 2.60 1.16 2.33 1.40 1.17 1.28 1.81 1.16 1.81

3.23 2.41 1.40 2.31 1.70 1.28 1.04 1.55 1.29 1.80

3.30 2.50 1.28 2.32 1.55 1.22 1.16 1.68 1.22

aStern height ( m ): species, LSD ~<0.01 = 0.23 m; spacings, n.s. hBasal stem diameter ( cm ) : species, LSD ~<0.01 = 0.31 cm; spacings, n.s.

had grown 45 cm high. A similar trend was observed in root growth and total dry matter production. One of the reasons for the better performance of Melia could be that it is a native of Kashmir and Baluchistan (Pearson and Brown, 1932). For this reason it showed greater growth during the winter months than the other species, when in general temperatures were unfavourable but the moisture regime was favourable to growth. All the other species of trees seem to be slow starters and are generally grown on longer rotations than the two fastest growing species. There was no interaction between species and fertilizer dose for either of the measurements, but the treatments with 50:50:50 kg ha-1 of N:P2Os:K20 gave significantly greater plant height and basal stem diameter than the treatments with no fertilizer. No significant difference was found in growth between the 50 and 100 kg h a - 1 fertilizer levels. Also no significant difference was found in percentage seedling survival between the treatments. Since there was considerable variation in the soil depth between plots, the percentage survival, diameter and height data were correlated with the actual soil depth, but the coefficient of determination was found to be less than 3%, confirming the assumption that very little of the variation in survival rate and growth parameters was due to soil depth.

Influence of spacing Leucaena showed significantly greater height and basal stem diameter than Melia for both spacings (Table 3 ). For basal stem diameter, Melia and Cassia

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siamea were on a par. There was no significant difference between the two spacings (Table 3 ). A significant interaction was observed between the species and spacings for plant height and percentage seedling survival. Leucaena and Melia performed better at 5 X 0.6 m giving 24 and 30 cm greater average height and 12 and 20% greater survival rate, respectively. Prosopisjuliflora and Dalbergia sissoo on the other hand gave 26 and 39 cm greater height at 3 X 1 m than at 5 X 0.6 m ( Table 3). Acacia nilotica var. indica and Dalbergia had a survival rate a b o u t 20% higher at 3 X 1 m than at 5 X 0.6 m. There needs to be further examination of this interaction before it can be adequately explained. Cassia had the lowest survival rate at 62%, all other species being on a par. The coefficient of determination for correlation between soil depth and the growth p a r a m e t e r s was about 7%. Burley (1982) pointed out t h a t though there are some technical problems with afforestation in arid zones, solutions are being found. E x p e r i m e n t s such as the ones carried out here will no doubt provide some of the solutions. More important than these technical problems are social features and economic constraints. An attempt has been made by Sharma (1984) to evaluate the cost of these plantations. This research on species evaluation will help us to understand the causes of deterioration of semiarid areas and to assess the economic parameters of tree growing in these areas. CONCLUSIONS

These experiments to assess eight tree species at different fertilizer levels and spacings indicate that L. leucocephala and M. azedarach are the most promising under limited irrigation when harvested on a short rotation basis. It seems worthwhile applying 50:50:50 kg h a - 1 of N:P2Os:K20 for early establishment of trees. The data on spacing comparisons will give more meaningful conclusions after competition has started.

REFERENCES Bhumbla, D.R. and Khare, A., 1982. Estimate of wastelands in India. Society for promotion of Wastelands Development (SPWD), N e w Delhi, 16 pp. Burley, J., 1982. Obstacles to tree planting in arid and semi-arid lands: Comparative case studies from India and Kenya. The United Nations University,Tokyo, 52 pp. Dabadghao, P.M. and Shankarnarayan, K.A., 1973. The Grass Cover of India. Indian Council of AgriculturalResearch, N e w Delhi, 713 pp. Desai, S.N. and Patil,S.K., 1986. Performance of tree species for biomass production on wastelands.In: N.G. Hegde and P.D. Abhyankar (Editors),The Greening of Wastelands. Proc. Natl. Workshop on Utilizationof Wastelands for Bio-energy, Pune, India,27-29 April 1985. Bharatiya Agro IndustriesFoundation, Pune, pp. 19 I-192.

251 Halliday, J., 1984. Register of nodulation reports for leguminous trees and other arboreal genera with nitrogen fixing members. Nitrogen Fixing Tree Res. Rep., 2: 38-45. Hegde, N., 1983. Leucaena forage management in India. In: Proceedings of the Workshop on Leucaena Research in the Asian-Pacific Region, 23-26 November 1982, Singapore, pp. 73-78. Jones, R.J., Villamizar, G. and Cook, S.J., 1983. The effect of seed treatments and nitrogen fertilizer on seedling growth of Leucaena. Leucaena Res. Rep., 4: 4-5. National Commission on Agriculture (NCA), 1976a. Report on climate and agriculture. Part IV. Govt. of India, Ministry of Agriculture and Irrigation, New Delhi, 638 pp. National Commission on Agriculture (NCA), 1976b. Report on Forestry. Part IX. Govt. of India, Ministry of Agriculture and Irrigation, New Delhi, 457 pp. Nerkar, V.G., 1984. Irrigated subabul plantations in Yavatmal district for raising biomass. Indian For., 110(9): 861-867. Pearson, R.C. and Brown, H.P., 1932. Commercial timbers of India (2 Vols.). Govt. of India, Calcutta, pp. 239-241. Relwani, L.L., Lahane, B.N. and Khandale, D.Y., 1986. Performance of different tree species on arid mountainous wastelands. In: N.G. Hegde and P.D. Abhyankar (Editors), The Greening of Wastelands. Proc. Natl. Workshop on Utilization of Wastelands for Bio-energy, Pune, India, 27-29 April 1985. Bharatiya Agro Industries Foundation, Pune, pp. 114-116. Shankarnarayan, K.A. and Shankar, V., 1984. Grasses and legumes for forage and soil conservation. Indian Council of Agricultural Research, New Delhi, 155 pp. Sharma, K., 1984. SPWD-NABARD Seminar on 'Economics of Wastelands Development', sponsored by National Bank for Agricultural and Rural Development, Bombay, 112 pp.