All the studied sites lying between 1090-2060 m amsl, were located in the Bhetagad watershed (290, 50’ to 290, 55’ N and 790 02’ to 790, 30’, E), which is a micro watershed of Garur Ganga watershed, Indian central Himalaya. A landuse survey of the study watershed revealed that 55.58% of the watershed area is covered by forest, 42.34% by agriculture/settlement and 2.08% by barren land (Joshi, 2002). Apart from the encroachments, the forest is also exploited for various purposes such as fuel wood, timber and leaf litter by the rural communities. The watershed had a warm temperate type of climate with distinct different seasons viz, spring, summer, monsoon, autumn and winter. Meteorological data showed that the area had a mean annual maximum temperature in June (360 C) and minimum in January (040 C) for the year 1999. The investigation was carried out on five categories of existing and three categories of intervened land systems located between the elevation ranges 1200-1400 m amsl (lower elevation) and 1600-1800 m amsl (upper elevation) (Table 1&2).
Plant species richness and vegetal cover
Species richness was analysed by counting the number of plant species in each study plot. For analyzing vegetal cover related parameters, such as plant density, basal area and crown canopy area, methods by Mishra (1968) were followed. Ten quadrates (50x50 cm size for grasses/herbs and 10x10 m for trees) were laid at each site, including respective erosion plots.
Soil samples were collected from three-locations for each of the five categories of non-arable sites (existing sites) at 0-20 cm soil depth from March 1999 to September 2002 at an interval of six months, whereas nutrient pools for three agroforestry systems (intervened land systems) were estimated an annual interval (in the month of September of 1999 and 2000). The Physico-chemical characteristics of the soil have been analysed following Jackson (1968). The soil moisture for all the land use was determined using soil moisture equipments (Trase system, USA) and computed mean for the year was calculated. Data were analyzed statistically following Snedecor and Cochran (1967).
Table 1. Computed mean of soil characteristics for different landuses at two elevation of Bhetagad watershed (0-20 cm soil depth, n =6)
|
Landuse |
Elevation
|
Moisture (%) |
pH |
O.M. (%) |
O.C. (%) |
Total N (%) |
C:N ratio |
Available P (kg/ha) |
Available K (kg/ha) |
|
Reserve forest (mixed) |
UE |
34.42 ±2.42 |
6.13 ±0.10 |
4.60 ±0.32 |
2.67 ±0.18 |
0.20 ±0.02 |
13.77 ±1.15 |
18.51 ±1.45 |
269 ±13 |
|
LE |
33.20 ±3.35 |
5.92 ±0.05 |
5.37 ±0.32 |
3.11 ±0.19 |
0.15 ±0.01 |
20.83 ±1.53 |
18.52 ±1.35 |
281 ±13 |
|
|
Open forest |
UE |
22.82 ±2.72 |
6.06 ±0.05 |
1.92 ±0.23 |
1.09 ±0.12 |
0.10 ±0.01 |
10.78 ±0.70 |
12.75 ±1.96 |
200 ±12 |
|
LE |
26.82 ±3.72 |
6.72 ±0.04 |
2.49 ±0.21 |
1.44 ±0.12 |
0.11 ±0.01 |
12.75 ±2.11 |
22.35 ±1.91 |
209 ±12 |
|
|
Agriculture terrace riser |
UE |
19.56 ±2.00 |
6.19 ±0.07 |
2.64 ±0.20 |
1.53 ±0.11 |
0.26 ±0.01 |
5.81 ±0.31 |
23.30 ±1.93 |
281 ±11 |
|
LE |
23.33 ±1.90 |
6.84 ±0.05 |
2.88 ±0.26 |
1.67 ±0.15 |
0.24 ±0.02 |
7.54 ±0.52 |
22.94 ±1.89 |
271 ±14 |
|
|
Grass land |
UE |
22.41 ±1.95 |
6.26 ±0.04 |
2.51 ±0.18 |
1.50 ±0.11 |
0.17 ±0.01 |
8.85 ±0.42 |
18.57 ±1.89 |
259 ±10 |
|
LE |
24.20 ±3.48 |
6.30 ±0.03 |
2.64 ±0.26 |
1.53 ±0.15 |
0.15 ±0.01 |
9.93 ±0.41 |
20.98 ±1.82 |
284 ±16 |
|
|
Grazing land |
UE |
11.58 ±1.40 |
6.26 ±0.06 |
1.17 ±011 |
0.68 ±0.06 |
0.08 ±0.01 |
8.57 ±0.25 |
124.35 ±2.11 |
145 ±12 |
|
|
LE |
14.32 ±3.08 |
6.17 ±0.05 |
1.32 ±0.18 |
0.76 ±0.10 |
0.08 ±0.01 |
9.26 ±0.74 |
121.71 ±2.07 |
141 ±12 |
|
Parameter |
|
|
|
|
|
|
|
|
|
|
Elevation |
|
0.05 |
0.05 |
0.05 |
0.05 |
0.05 |
0.05 |
0.05 |
NS |
|
Landuse |
|
0.05 |
0.05 |
0.05 |
0.05 |
0.05 |
0.05 |
0.05 |
0.05 |
|
Elevation x Landuse |
|
NS |
0.05 |
NS |
NS |
0.05 |
0.05 |
0.05 |
0.05 |
|
LSD (0.05)
|
UE |
5.55 |
0.14 |
0.62 |
0.35 |
0.05 |
3.85 |
11.83 |
99.60 |
|
LE |
8.90 |
0.13 |
0.71 |
0.41 |
0.03 |
5.52 |
11.28 |
104.00 |
UE= Upper elevation, LE=Lower elevation, Ψ beneath each column P values associated with an analysis of variance (ANOVA) are given, with LSD values (P=0.05) when the interaction is significant, NS= Not Significant
RESULTS AND DISCUSSION
All the studied non-arable existing lands had almost similar herbs species, but their dominance varied across the sites. Surface vegetal cover was higher (%) for upper elevation as compared to the lower elevation landuse system. Tree density, total tree basal area and crown cover were high in upper elevation for same type of forest.
Table 2. Annual variation in soil characteristics of different agroforestry systems of Bhetagad watershed
|
Parameters |
Agro forestry type |
Upper elevation |
Lower elevation |
||||
|
2000 |
2001 |
2002 |
2000 |
2001 |
2002 |
||
|
Soil moisture (%) |
Fodder plantation |
8.9 ±2.1 |
10.2 ±3.4 |
10.3 ±1.8 |
6.3 ±1.8 |
8.4 ±2.9 |
8.5 ±1.3 |
|
Tea plantation |
11.2 ±3.1 |
13.4 ±2.2 |
14.4 ±1.1 |
9.4 ±1.3 |
10.8 ±1 |
11.1 ±0.8 |
|
|
Horticulture |
10.2 ±1.8 |
13.4 ±1.9 |
13.9 ±1.2 |
12.2 ±1.6 |
14.8 ±1.4 |
14.4 ±0.9 |
|
|
Organic Carbon (%) |
Fodder plantation |
0.88 ±0.06 |
0.96 ±0.14 |
0.98 ±0.09 |
0.76 ±0.05 |
0.89 ±0.09 |
0.92 ±0.04 |
|
Tea plantation |
0.92 ±0.09 |
1.05 ±0.11 |
1.08 ±0.05 |
0.81 ±0.04 |
0.98 ±0.07 |
1.01 ±0.02 |
|
|
Horticulture |
1.11 ±0.04 |
1.18 ±0.08 |
1.22 ±0.03 |
1.15 ±0.02 |
1.29 ±0.03 |
1.31 ±0.03 |
|
|
Total-N (%) |
Fodder plantation |
0.093 ±0.002 |
0.098 ±0.008 |
0.099 ±0.001 |
0.09 ±0.001 |
1.034 ±0.002 |
1.052 ±0.001 |
|
Tea plantation |
0.122 ±0.014 |
0.127 ±0.011 |
0.131 ±0.01 |
0.102 ±0.002 |
0.111 ±0.002 |
0.113 ±0.001 |
|
|
Horticulture |
0.111 ±0.013 |
0.118 ±0.013 |
0.119 ±0.01 |
0.109 ±0.003 |
0.118 ±0.002 |
0.121 ±0.001 |
|
|
Available P (kg ha-1) |
Fodder plantation |
13.71 ±0.92 |
15.84 ±1.12 |
16.73 ±0.61 |
11.52 ±0.88 |
17.81 ±0.91 |
18.57 ±0.67 |
|
Tea plantation |
27 ±1.09 |
31 ±1.96 |
28 ±1.11 |
14.5 ±0.91 |
19.9 ±0.71 |
20.5 ±0.69 |
|
|
Horticulture |
23 ±1.01 |
27 ±2.07 |
28.2 ±1.11 |
22.5 ±0.91 |
29.9 ±0.55 |
31.5 ±0.38 |
|
|
Available K (kg ha-1) |
Fodder plantation |
116 ±3 |
122 ±4.1 |
124 ±1.3 |
110 ±2.0 |
122 ±4.0 |
127 ±1.5 |
|
Tea plantation |
119 ±2.2 |
139 ±2.4 |
141 ±1.8 |
127.0 ±4.0 |
140. ±3.0 |
141 ±2.0 |
|
|
Horticulture |
112 ±2.6 |
128 ±2.1 |
132 ±1.6 |
147 ±2.0 |
160 ±4.0 |
161 ±1.0 |
|
The soil moisture was higher in the upper elevation and in between different landuse categories; the reserve forest had higher value of soil moisture. This increased with the increasing of the surface vegetal cover, plant species richness, tree density and crown cover in different landuse categories. The soil pH of studied sites was acidic for reserve pine forest (5.90 - 6.13) and neutral for agriculture terrace riser (6.72 - 6.84) unit. The organic matter (4.60 - 5.71%) and organic carbon (2.67 - 3.11%) were higher in reserve forest due to infinitesimal influences of indiscriminative activities. Total N (%) increased in agriculture terrace riser (0.24 - 0.26%), but a reverse trend was observed for pine forests and grazing land. This was due to the addition of FYM and inorganic fertilizer in agriculture land. The low total-N and high C: N ratio for the pine forests indicated low net rate of mineralisation in forest area (Table 1). These factors caused high accumulation of leaf litter throughout the year in partially decomposed category as a result of slow decomposition (Chaturvedi et al., 1988). Comparatively higher available P was recorded for grazing land (21.71 - 24.35 kg/ha) due to less grass biomass produced under intensive grazing causing less absorption of P from the soil, resulting in a build up of available P in grazing land and open pine forest. This attribute was also observed by Singh (1999). The removal of grasses in a short span (every 15-20 days) from rain fed agriculture riser was the main cause of higher availability of the P. The available K was high at lower elevation (141 - 281 kg/ha) for all the studied sites.
Management strategies
Due to high requirement of fodder, fuel wood and ground vegetal biomass for different uses in both the elevations, the inhabitants had no alternative options other than the existing practices. Thus in such circumstances, each elevation has a need to adopt alternative sustainable agroforestry options. These practices must be helpful to maintain the nutrient soil pools and water availability. These practices would be sufficiently fulfilling requirement of the good quality fodder. The forests and grazing sites showed lower soil moisture and nutrients. In case of the reserve forests and grassland soil, the ground cover, soil moisture and nutrient pool almost remained in good conditions. Thus the initiation of community forest with Alnus nepalenses, Dalbergia sissoo and Bauhinia Vahli, and other species may be an additional nutrient maintaining measure for the watershed. The tea cultivation and horticultural practices may also be helpful in maintaining the nutrient balance as well as income generation of the local community. Thus the community forestry, tea cultivation and horticultural practices in watershed may be profitable and ecologically sustainable. The aforesaid management strategies may help to maintain the soil nutrient pools and improve the economy of the inhabitants of the watershed.
Tested agroforestry models for non-arable landuses
In the Bhetagad watershed the problems related to the poor crop productivity of mismanaged non-arable land can be compensated by initiating community forestry, tea plantation and horticultural trials, which would enhance better livelihood opportunities for the user groups. The main three soil improving and income generating trials, i.e., (i) fodder tree with nutritious grasses, (ii) tea cultivation with fodder trees, (iii) horticulture system were identified and selected for detailed evaluation. These agrofortestry practices were quite common in both the elevations. The Albiziza stipulata, Delbergia sissoo and Alnus napalensis are fast growing leguminous trees that are believed to increase the soil fertility levels. Besides, Grewia optiva and Quercus leucotrichphora are also important for satisfying the fodder, fuel and other uses. These species are also helpful in improving the soil moisture and nutrient pools.
A wide variation was recorded in soil moisture, soil pH and nutrient pools for all the three category of agro-forestry system in a land elevation range (1200-1400 m amsl) through out the investigation period from 1999 to 2001 (Figures1-5). In general, a slight variation in soil characteristics has been observed in between the elevation for same landuse system. The soil moisture and C/N ratio increased for upper elevation, whereas the nutrient content and pH value increased for lower elevation. The increase in soil moisture due to increase in the biomass and comparatively low temperature favoured these facts. The slight increase in soil nutrients pool in lower elevation, due to comparatively high temperature and high relative humidity, favoured high rate of nutrient mineralisation from decomposed and semi-decomposed organic residues/shadings. The lower increase in C/N ratio for upper elevation indicated low temperature, low relative humidity and high soil moisture favouring to high organic matter accumulation and low rate of nutrient mineralization. The fodder tree plantation showed higher increase in soil moisture and soil nutrient pool.
Introduction of fodder trees and grasses are more effective measures to improve the soil moisture and nutrient pools in both the elevations of the watershed. Even though the tea cultivation and horticultural practices are more income generating than the fodder species, nevertheless in the present circumstances the requirements of a good quality fodder species could not be replaced by other means. Further, the community forestry will also help on strengthening the community institutions and different developmental activities for extension of the programs.
 |
Figure 1: Soil moisture (%) under different agroforestry systems at 1200-1400 masl in Bhetagad watershed
 |
Figure 2: Soil organic carbon (%) under different agroforestry systems at 1200-1400 masl in Bhetagad watershed
 |
Figure 3: Nitrogen (%) under different agroforestry systems at 1200-1400 masl in Bhetagad watershed
 |
Figure 4: Phosphorus (Kg/ha) under different agroforestry systems at 1200-1400 masl in Bhetagad watershed
 |
Figure 5: Potassium (kg/ha) under different agroforestry systems at 1200-1400 masl in Bhetagad watershed
Tested fertility options for the arable land
Bio-composting practices
The bio-composting practices are important tools for improving the soil moisture and nutrient pools of highly degraded area like agriculture land within the watershed. The bio-composting efforts may quickly enhance the nutrient status without losing more nutrients and also in improving the water adhering properties of the soil. Five types of composts were prepared by using soil, broad leaves, poultry wastes, vegetables, grasses and agriculture wastes, which could be easily collected from the farming systems. The nutrient pool of these composts was estimated through chemical analyses. The status of these compost materials showed the different composition of organic carbon, organic matter, total N, available P and K.
The chemical analysis of different composts showed that the broad-leaved with poultry wastes had narrow C/N ratio but had higher available P and K than the other composts. Such types of bio-composting practices may be important measures for improving the soil fertility in different soil amending practices as well as other community land improvement. The C/N ratio is also good indicator for net carbon and nitrogen mineralisation. The available P and K also increased quite significantly in different composting systems (Table 3).
Table 3. Nutrient status of different compost composition at Bhetagad watershed
|
Compost type |
Organic matter (mg/g) |
Organic carbon (mg/g) |
Total N (mg/g) |
Available P (mg/g) |
Available K (mg/g) |
C:N ratio |
|
A |
13.54±1.22 |
7.84±0.70 |
0.94±0.04 |
0.06±0.01 |
0.78±0.03 |
8.3±0.42 |
|
B |
19.32±1.81 |
11.20±1.05 |
2.12±0.02 |
0.34±0.02 |
1.21±0.02 |
5.2±0.50 |
|
C |
37.89±2.02 |
21.96±1.17 |
3.79±0.05 |
0.49±0.02 |
1.39±0.02 |
5.8±0.62 |
|
D |
32.41±1.78 |
18.79±1.03 |
2.93±0.03 |
0.36±0.01 |
1.27±0.02 |
6.4±0.044 |
|
E |
44.23±2.34 |
25.64±1.36 |
5.46±0.03 |
0.51±0.02 |
1.41±0.03 |
4.7±0.58 |