The rainfall during 2003 was adequate in Kerala and more in Tamilnadu. But it was less compared to the rainfall of 2001 and 2002 in all the coffee zones of Karnataka except in Magge Liaison zone of Hassan region and Virajapet and Siddapur liaison zones of Kodagu region (Fig. 1). The deficit of rainfall was ranging from 6.43 (Hassan) to 14.26% (Chikmagalur) compared to the year 2002. Higher deficit of 12.42 to 27.25% was noticed compared to the year 2001 in Karnataka. Where as the liaison zones of Kerala and Tamilnadu had higher rainfall compared to previous years (Fig.2).

In Chikmagalur region, Giris and Chikmagalur liaison zones received only 798 to 990 mm rainfall during the year 2003. This low precipitation consecutively for the second season has affected the growth and developments of plants. Hanbal liaison zone of Hassan had a deficit of 16.32% compared to the year 2002. In Kodagu region, the deficit rainfall was to an extent of about 25% compared to the previous years in Somwarpet liaison zone. Similarly Shanivarsanthe zone also had a deficit of more than 10.52% compared to previous years (Tablel ).

In Kerala state majority of the liaison zones received more rainfall compared to previous year except in Sulthan Batthery, Meenangadi, Mananthawadi and Chundale where the rainfall deficit was 20.76, 19.44, 13.55 and 12.01 % respectively. Where as the coffee tracts of Tamil Nadu state received higher rainfall compare to previous years except Gudalur liaison zone, which had a deficit of more than 21% (Table 2).

Rainy Days

The number of rainy days was less in Chickmagalur (22,12) compared to 2001 and 2002 seasons respectively. However not much difference could be observed in Hassan and Kodagu regions with number of rainy days. The rainy days were less by 22 and 4 days compare to last year and 2001 season in Kerala zone. Improvement in number of rainy days was noticed in Tamil Nadu coffee tracts compare to previous year and 2001 season (Fig. 3).

Summer Showers (January to May 2003)

The summer shower was in deficit ranging from 24.52 to 66.08% in the liaison zones Balehonnur, Aldur, Giris and Kalasa of Chikmagalur region compared to 2002. Similarly Yeslur and Belur zones of Hassan region recorded a deficit of 65.24 and 33.10%. Liaison zones of Shanivarsanthe, Virajpet and Gonikoppal had higher deficit compared to last year (Table 3). The deficit rainfall of summer period was observed in Kalpetta and Sulthan Bathery zones of Kerala and Adalur zone in Tamilnadu (Table 4).

Southwest monsoon Rainfall (June to September 2003)

In general the South West Monsoon was weak during the year. Compared to the year 2001, the deficit was more than 53.88% in Chikmagalur zone. Similarly Belur zone had a deficit of 47.75% compared to 2001. However the rainfall showed marginally improved pattern compared to the year 2002. Somwarpet liaison zone had a deficit of more than 22% compared to the previous years. However good rainfall was received during the year in Gonikoppal, Virajpet and Siddapur compared to last year (Table 5). The average rainfall of Southwest monsoon was more by 5.98% compared to 2002, but it was less compared to the year 2001 in Kerala. Except Gudalur, all the liaison zones of Tamilnadu had received excess rainfall compared to last year (Table 6).

North-East Rainfall. Pattern (October to December 2003)

In Chickmagalur region the North-East Monsoon was weak compared to 2002 and 2001. However the liaison zones such as Giris, Koppa and Balehonnur received comparatively higher precipitation. In general the Monsoon was found weak in Hassan and Kodagu regions compared to previous years of 2001 and 2002. The Northeast rainfall was active during the month of October and rainfall was minimum during November. No rainfall was received during December in Chickmagalur, Hassan and Kodagu regions. The deficit was more than 30% in many zones and it was to the extent of 87.28% in Gonikoppal (Table 7). This caused early soil moisture stress in these regions.

In Kerala state also the Northeast monsoon during the season was less in majority of the liaison zones compared to the years 2001 and 2002. However in Tamil Nadu state, all the coffee liaison zones received higher Northeast monsoon rainfall during the year 2003 compared to the previous years (Table 8).

Highlights of Weather 2003

The rainfall was optimum in Kerala. Karnataka experienced low rainfall consecutively for the second season. The drought days, i.e. the gap between the last rainfall of 2002 to the first rainfall of 2003, were 136, 158 and 152 respectively in Balehonnur, Magge and Somwarpet Liaison zones of coffee. No rainfall was received during May and up to 10th June, 2003 in most of the coffee tracts of Karnataka. The Southwest monsoon was less active. The Northeast monsoon failed in all the three states of South India, which resulted in no rainfall scenario from November onwards. This has aggravated the low soil moisture status in the plantations. On account of low precipitation, the ponds and storage tanks have not filled to its maximum capacity and drying of steams was noticed earlier than the normal period. This resulted in acute water shortage in most of the plantations.

Impact of the Rainfall on Crop 2003-04

No adverse effect was noticed on the developing berries in the Plantations of Kerala and Tamilnadu except the delayed fruit ripening in certain packets. Although Tamilnadu received good spread over rainfall during 2003, the low rainfall during the preceding years affected the cropping wood and the harvested crop was very low for the year 2003. Whereas plantations in Karnataka had following impact on the crop:

Insufficient showers affected blossom and fruit set. No rainfall for the period from May to 12th June 2003 hampered the normal development of berries. Fruit maturity was delayed. Fruit ripening was late by 15 to 30 days. Percent ripening was less in the low rainfall area of around 750 mm. Percentage of float was high to an extent of 10 to 12% against the normal percentage of below 5%. During the first round of crop harvest, the percent wet parchment was less, which improved later on during subsequent harvests. The percentage of "A" grade beans in arabica coffee was around 22 to 33% during the first round of crop harvest, which improved to 40 to 65% during subsequent round of picking. The plantations, which received adequate rainfall and also plantations of high altitude have shown normal percentage of 52.40 to 82.18% "A" grade beans. The plantations affected with drought had low percentage of "A" grade beans to an extent of 37.18 to 56.13%. This was mainly due to the lack of adequate soil moisture during the initial berry development up to 103 days from blossom. Post blossom foliar spray of nutrients with hormone was found to be helpful in minimizing the stress effects on bean development (Endosperm filling). The low inputs strategy, such as skipping of one round of fertilizer and Bordeaux mixture spray applications further decreased the percentage to 29.29, 31.15 and 32.0% respectively at Chikmagalur, Hassan and Kodagu regions.

Greater reduction of "A" grade percentage beans was noticed in the drought-affected area of Arsinaguppe and Mallandur at Chikmagalur region, Sakleshpur at Hassan region and Shanivarsanthe at Kodagu region. The out-turn ratio of fruit to clean coffee was found to be more than the normal ratio of 6:1 for arabica coffee in drought affected area. This might be due to less mucilage content, bean weight, bean volume etc. On account of this, there was some reduction from the estimated crop to the actual crop harvested. No adverse effect of less rainfall on coffee quality of robusta coffee was observed so far. Incidence of leaf rust was found to be low, whereas the white stem borer incidence was high.

Weather 2004 in Coffee Growing Tracts

The weather continued to be dry and hot all over coffee plantations in Karnataka, Tamilnadu and Kerala States during current year. Days of drought so far prevailed were ranging from 135 to 160 days in Karnataka zones. Yellowing, wilting symptoms and defoliation were first noticed in Dadap plants (Fig.4). The sub-soil moisture was very low in most of the plantations. The plants in marginal area and open conditions exhibited wilting symptoms (Fig.5).

Scorching of young coffee was observed. The cropping wood was less due to low soil moisture. The incidence of termites was found to be more on shade trees (Fig.6). The drought ameliorative sprays (DAS) such as either NPK+Zinc or Lime spray during January and Februay were found helpful in alleviating the stress effects.

Receipt of insufficient showers of 3 to 15 mm during February was reported from Besagoor, Gonikoppal zone at Kodagu region and also 20% area of Sulthan Bathery, Panamaram, Kalpetta and Chundale liaison zones in Kerala. The rest of the zones were not in receipt of showers up to 16th March 2004 except Magundi (25mm) at Balehonnur zone of Chikmagalur region. Since the rainfall was low, the blossom was partial and showed more abnormalities like pinking (Fig.7), which might cause reduction in fruit set. Irrigation for robusta coffee could not be undertaken in many of the plantations due to non-availability of water. The plantations, which have given blossom irrigation in the anticipation of showers, could not undertake backing irrigation due to lack of water. It is very much essential to receive adequate showers within March 2004 so that further damage to the cropping wood could be minimized. In fact during 1982-83, when the drought days were around 168 to 180 days, there was a crop reduction of 9917 and 45054 MT respectively for arabica (12.3%) and robusta coffee (56.74%) from the wood estimates of 1983-84.

If the present drought period extends further, there will be similar crop reduction both in arabica and robusta coffee for the current season 2004-05. However the crop reduction will be high in robusta on account of its susceptibility to drought and also limitation for undertaking irrigation.

Suggestions

Under the present situation of low soil moisture status and dry weather, it is advisable to delay the shade regulation up to receipt of good rainfall and probably it may be carried out during May. Similarly, pruning of arabica coffee may be undertaken after the receipt of rainfall as the reserve status (sugars and starch) of the wood is low and also to avoid the plants from further exposure to hot weather conditions. After receipt of blossom showers, a foliar spray of 1kg urea in combination with 1 kg single Super Phosphate, 0.5 kg MOP and 75 ml Planofix per 200 litres of water and 400 to 600 litres of solution per acre could be given 15 days after blossom. This will facilitate to improve the fruit set and vegetative growth.