Grasslands and other grazing resources occupy a very important position in the hill agriculture and the grassland utilization is an important component of the hill farming system. The herbage utilized during grazing is the largest fodder resource followed by crop residues, tree leaves, concentrates and cultivated fodder. The land constraint has always guided the farmers to utilize most of the cultivated land for food production. Fodder cultivation is the last priority in the hills. This fact, further strengthens the importance of grasslands for the sustenance of huge population of livestock.

Besides grazing, these grasslands are also used for harvesting hay which is essential for maintaining the livestock during lean periods. The privately owned grasslands known as Ghasnis or Khadetar in Kangra Valley are enclosed during monsoons to achieve higher hay production. The standing biomass which comprise of grasses like Chrysopogon gryllus, Arundinella nepalensis, Imperata cylindrica, Paspalum notatum, Heteropogon contortusetc. is harvested during October-November and is conserved for use during winter. Some of the farmers let the biomass stand in their grasslands and harvested it on day-to-day requirement basis. By this time (October-November) the biomass is only dry and fibrous grass which has lost most of its nutritive value. The standing biomass production declined from 12.03 t/ha harvested on 25th September to 9.97 t/ha harvested on 5th November. Similarly a decline in crude protein percentage and increase in crude fiber percentage takes place with the delay in harvesting time. The crude protein percentage of 6.90 recorded on 5th September declined to 5.14% till 5th November. The crude fibre percentage of 31.05 recorded on 5th September increased to 35.60 till 5th November (Majid, 1983).

The farmers have shown their inability to harvest the herbage at earlier dates because of their occupation with the other agricultural pursuits. It is only after October when they are free from the Kharif crop harvest and post harvest engagements, that they can spare time for grass harvest. A suitable alternative time frame needs to be determined for the farmers so that they achieve maximum qualitative and quantitative production from their grasslands. A year round distribution of rainfall (Table 1) further strengthen the prospects of herbage availability at alternate dates.

Table 1. Climatic parameters of the study site

This communication aims to present the findings of an investigation carried out on a protected grassland at Palampur (Kangra Valley) to determine its biomass regeneration potential. The spectrum of biomass availability at different periods of a year could help in determining alternative dates for farmers to harvest their grasslands for making hay.

Material and Methods

A well protected grassland representing typical grassland situation of Kangra Valley was identified in the Himachal Pradesh Krishi Vishvavidyalaya campus near Seed Production Department. The flat portions of the grassland support white clover (Trifolium repens L.) dominated vegetation while the slopes support grass dominated vegetation. The grasslands have never been fertilized and are rainfed. Ten permanent quadrates each of 1 x 1 m size were laid out in both the legume and grass dominated grasslands. The vegetation from these quadrates was manually clipped on 8th day of every month. The fresh weight of the herbage was recorded in the field only. 500 gms of green herbage from each sample was oven dried at 60^o C for determining the dry weight. Average of biomass production recorded from ten quadrates was taken as the representative figure. In case of legume dominated grasslands biomass was partitioned into grasses and legumes and their weights were recorded separately. The weed/forb biomass was negligible.

The grasslands of Kangra Valley record maximum biomass production during monsoon and remain dormant during winter (October-February). In order to determine the regeneration of vegetation during different seasons which coincide with the native agricultural practices, the year was classified under three seasonal categories viz., Pre-monsoon (March-June), Monsoon (July-September) and Winter (Oct.-Feb.). The regeneration potential during pre-monsoon period is presented in this paper.

Observations

Observations recorded on green and dry herbage yield and its increase and decrease are presented in Tables 2 and 3. In case of the legume dominated grasslands maximum green herbage yield of 6.62 t/ha and 1.2 t (dry)/ha was recorded in the month of May. The grasses contributed 0.83 t/ha (fresh) and 0.19 t/ha (dry) while the white clover contributed 5.79 t/ha (fresh) and 1.01 t/ha (DM). This was the maximum grass biomass recorded during pre-monsoon period. The minimum production of grass (0.19 t/ha) and white clover (0.89 t/ha) was recorded during March and June respectively. The moisture content in both grasses and legume was highly variable. In case of grasses maximum and minimum dry matter percentages of 75.0 and 22.9 were recorded in April and May respectively. In case of legume the variation was not so well pronounced. Maximum and minimum dry matter percentages of 25.74 and 18.13 were recorded during June and May respectively.

Table 2. Herbage recovery from legume dominated pasture

In case of grass dominated grasslands the biomass recorded during pre-monsoon period was significantly lesser than the legume dominated grasslands. A maximum herbage yield of 0.39 t/ha (fresh) and 0.16 t/ha (dry) was recorded during June. The dry matter percentage ranged between 40 and 50 being recorded during April and May respectively.

Table 3. Herbage recovery from grass dominated pasture

As far as the increase in the regenerated biomass is concerned, in legume dominated grasslands an increment of 48.38% and 53.47% was recorded during April and May respectively in case of green herbage yield. The dry matter production recorded an increment of 36.17 and 60.83% during April and May respectively. During June, the biomass production declined by 386.8 and 242.9% in case of fresh and dry matter respectively.

The grass dominated pastures exhibited a slow and insignificant progression in biomass production while the fresh herbage production remained static during March and April, a decrease of 16.67% was recorded in dry matter production during April. During May, the fresh and dry matter yields declined by 36.36% and 9.08% .1h12 respectively. IT was only during June that an increment of 43.6 and 31.25% was recorded in fresh and dry matter production respectively.

Discussion
The observations recorded (Tables 1 and 2) have revealed that the regeneration in the grasslands is a continuous process which may add to or reduce the biomass production according to the availability of growth controlling factors like moisture, temperature etc. The gradual and progressive increase of biomass production in legume dominated grasslands may be correlated to a corresponding increase in the temperature. During March when thawing takes place in the plants after a dormant winter, the maximum day temperature is 21.1^oC which increases to 28.4^oC during May when maximum herbage is available from legume dominated pastures.

The poor growth of grasses may be attributed to the fact that most of the grasses growing in the grasslands are warm season grasses and require higher temperature and moisture for their optimum growth. The growth of grasses picks up during monsoon (July onwards) and it remains active even after the end of rainy season.

This differential growth pattern during pre-monsoon period offers a productive cut of leguminous herbage to the farmers. The green herbage yield of 6.62 t/ha can further be enhanced by various managemental intervention. April and May offer many sunny days to the farmers when the herbage can be dried into may which is very difficult to make during the following monsoon.

Reference
Majid, M.A. (1983) Effect of cutting dates, nitrogen rates and curing techniques on production and quality of hay from natural grasslands. M.Sc. Thesis, Deptt. of Agronomy and Agrometeorology, HPKV, Palampur.