Climate Change Adaptation Strategies for Tea Plantations. Future scenarios of climate change

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1 Climate Change Adaptation Strategies for Tea Plantations K. G. Prematilake Head AGRONOMY DIVISION Future scenarios of climate change With climate change, extreme weather situations along with steady rise in surface temperature are experienced Monthly temperature -by o C over the last 50 years There could be high variability in rainfall 2 1

2 Optimum rainfall requirement for tea cultivation in different AERs AER Optimum Rainfall (mm/month) Up Country Wet Zone 350±20 Mid Country Wet Zone 417±49 Low Country Wet Zone 223±38 Up Country Intermediate Zone 303±34 Mid Country Intermediate Zone 227±10 Under CC, two extremes i.e. either frequent dry spells or long overcast periods with excessive rains / Frost damages in the hill country could be experienced - Dry periods become more drier - Wet periods become more wetter 3 Impact of dry weather in the Low Country 1992 Feb-Mar 2007 Severe droughts were experienced during 1992, 2007, and 2012 While, Excessive rains were occurred during 2013 Similar kind of situations could be expected in the future as well 4 2

3 Impact of dry weather on tea growth & yield Leaf and Bark Desiccation Heavy Sunlight High Temperature High Evaporation Stem/Collar Canker Wood rot Lower RH Dormancy, Poor Bud Break & Bud Scorch Low or no Rain (<100 mm/month) Plant Casualties Aggressive Weed Growth Dry Weather Pests Formation of a Hard Pan on Ground Surface Low Productivity & Poor Quality 5 Incidence of pests and diseases under dry weather situation Collar Canker/ Stem canker/ Wood rot Insects - Mites Nettle grub Tea tortrix 6 3

4 Occurrence of weeds With rise in temperature weeds found in low country could be appeared in the mid and up country as well Weed growth becomes more aggressive Many incidence of Hard-to-kill weeds might be reported As a result weed control becomes more harder 7 AER Optimum Rainfall (mm/month) Yield drop due to 100 mm reduction in rainfall per month (kg/ha) Up Country Wet Zone 350±20 29±3 Mid Country Wet Zone 417±49 36±6 Low Country Wet Zone 223±38 55±7 Up Country Intermediate Zone 303±34 39±3 Mid Country Intermediate Zone 227±10 81±11 Yield could be reduced by kg /ha/month due to 100 mm drop in rainfall - Wijeratne et al,

5 Impact of Excessive rains Poor bud break Shoot development High intensity of rains Low Sunshine Cloudy & Gloomy High humidity Heavy soil erosion/degradation Lowering soil depth Reduced water holding capacity Poor soil nutrients status Poor drainage in low lying areas Fast spread of Fungal diseases(bb) Incidence of wet weather pests (Nematodes) 9 Yield loss due to excessive rains and low sun light during May-July 2013 at St. Coombs Estate 10 5

6 Tea production as affected by excessive rains and low sunlight during May-July 2013 in different ACRs Tea Production 2012/13 (Mn kg) According to the Agro-Climatic Regions Nuwara Eliya Mediums Westerns JAN FEB MAR APR MAY JUN JAN FEB MAR APR MAY JUN JAN FEB MAR APR MAY JUN Uvas Uda Pussallawa Low Country JAN FEB MAR APR MAY JUN JAN FEB MAR APR MAY JUN JAN FEB MAR APR MAY JUN According to the Diagnostic survey of the TRI (2011) Soil management is rather poor Soil is highly degraded Shade management is poor Many incidence of Pests and diseases About 18,800 ha in the RPC sector are found to be uneconomic Field condition - % of Satisfactory fields Land Management (Leader drains/contour drains) Shade Establishment Shade Management >3000 kg MT/ha/yr 68% 40-46% 40% <1500kg MT/ha/yr 28% 26-34% 24% As such situation of tea lands could be further worsen under 12 the Climate Change 6

7 Therefore, appropriate measures are to be adopted by stakeholders to minimize adverse impacts of CC on tea Adaptation strategies Drought Excessive rains Long term strategies Medium term Short term 13 Long term drought adaptation strategies 1) Selection of the most suitable areas a) With the use of new tea growing map/aer Map 14 7

8 Selection of suitable areas for tea Most suitable Nuwaraeliya Ratnapura Deniyaya/Kotapola Kalawana Moderately suitable Galle, Matara & Kalutara districts Some parts of Ratnapura, Kandy and Matale districts Do not expand replanting/ new planting into low/unproductive and marginal areas where the weather condition is dry and soil conditions are poor. Follow all adaptation strategies for existing cultivations in such areas Invest more on productive regions (Suitable/moderately suitable) Selection of suitable lands for tea cultivation b) Use Soil Selection Criteria : Climate, Slope, Soil depth, Gravel %, Rockiness, C) Use of Soil Quality Index Objectives: To determine the soil quality more precisely taking in to consider soil physical (BD, AWC), chemical (C% ) and biological (MBC, Nematode count) properties. To eliminate or reduce the time period of rehabilitation To pay more attention to the lands with poor soil quality 8

9 2) Use of drought tolerant cultivars To avert the impact of drought together with high temperature use hardy/drought tolerant cultivars for planting (DN, DG 7, DG 39, TRI 2025, TRI 4042, TRI 4052, S 106, CY 9, KP 204, CH 13 and KEN 16/3) Also use biclonal and polyclonal seed stocks for planting Use grafted tea combinations Tolerant to drought TRI 4054/DG 7, TRI 4053/DG 39 are found to be promising for dry weather conditions 17 3) Establishment of Medium and high shade trees (Erythrina lithosperma) Gliricidia sepium le,swekav%d lef,da;%siia (Calliandra calothrysus) Albizzia moluccana Gravillea robusta 18 9

10 Establishment of high and medium shade trees - Contd It is very essential to maintain the shade tree stand in 19 tea lands Shade management- - Contd It is essential to manage shades particularly in the low and mid country and in Uva region It reduces ambient temperature/ Prevents sun scorch thereby plant casualties When tea is exposed to sun light and ambient temperature is o C the leaf temperature rises above 40 o C. However, If shade trees are present leaf temperature limits only to >1-2 0 C above the ambient temperature (i.e o C)

11 Shade management Contd Leaf litter covers the ground and enrich the soil with N, P, K, and Carbon Shade trees also have a major contribution to Carbon sequestration particularly in low-grown tea Other advantages Improve net assimilation of tea leaf Reduce weed growth Add organic matter (leaf litter) Minimize wind damage 21 3) Management of shade to minimize adverse effects of disease problems Lopping and pollarding All medium and high shade trees should Lopped and pollard prior to rains to prevent tea from fungal diseases such as BB, Horse hair blight and Lichen growth on leaves 22 11

12 4) Rainwater harvesting for use during a dry spell Construction of ponds/ lakes Water shed management Establishment of forests covers on hill crests Planting trees on fences & boarders 23 Medium term strategies to adapt to the drought 1) Proper land preparation/forking to retain more water in soil Cutting of lateral drains of lock and spill type provided with silt pits / reverse slopes and Desilting 2) Soil rehabilitation with a grass 24 12

13 % Casualties 1/31/2014 Drought casualties of tea as affected by soil rehabilitation method Control Gautemala Mana Ginigrass Fig. Percentage of drought casualties 12 months after planting of tea at St Coombs Estate, Soil rehabilitation helps to minimize the drought casualties 25 (3) Rainwater harvesting a) From Factory roof /building roof/ House roof b) With burying of pruned litter Soil improvement with Organic matter Rain water harvesting 26 13

14 ud;dldj (4) Soil & Moisture conservation through establishment of green manure crops (Sesbania sesban) (Calliandra calothyrsus) (Flemingia congesta) (Crotolaria juncia) (Tithonia diversifolia) 27 5) Dry weather pruning should not be undertaken in all in the AERs during December March during June -August 6) Forking: should be practiced during rainy period to retain more water

15 Short term drought mitigation strategies 1) Follow the all soil moisture conservation measures Mulching the ground surface with a grass(@ 37 tons/ha) or Refuse tons /ha Lopping of cover crops and green manure crops before the on set of drought 29 2) Irrigation: If a water source is available micro irrigation can be practiced mainly during new clearing, young tea stage 3) Weed Management prior to dry spell to reduce the competition for moisture 30 15

16 4) Preparation for drought a) Spraying of SOP or MOP and Kaolin Spray 2% SOP or 2% MOP to reduce water loss by leaves (transpiration) (Spraying - One month prior to drought and continue at 2-4 week intervals depending on the severity). KAOLIN application: to reduce transpiration losses and to reduce the heat of leaf 5-10 kg/100 of water, soon after drought setting 31 5) Skiffing: Do a light skiffing to remove top most 2-3 of foliage [when young plants (from 2 nd - 4 th year) remained wilted during morning hours]. 6) Lop green manure crops and salt hedges before on set of drought o Cover crops should also be cut back to ground level before on set of drought 32 16

17 7) Pests: There could be outbreaks of dry weather pests such as mites, tea tortrix, nettle grubs It is to be vigilant on such pests and they should be controlled following integrated methods 33 How to adapt to the excessive rainy conditions? Long term strategies: 1) Soil conservation measures Both on-farm and off-farm measures to be given a high priority Use new recommendations especially, in off-farm (off-land) interventions 34 17

18 On farm and off farm practices Land preparation Cutting of drains Connect all contour drains to the Leader drain to remove excess water into the leader drain 35 Follow New technologies of Off- farm soil conservation measures - Leader drains 36 18

19 37 Off-farm conservation measures. Contd... Water shed management should be given a high priority to retain more water and to reduce the soil losses - Establishment of forest covers / - Cultivation of trees in the boarder areas On farm soil conservation measures: Contour planting Establishment of cover crops/ Leaving soft herbs Mulching Proper bush management Infilling 38 19

20 2). Identification of most vulnerable areas/ lands for water logging Avoidance of Low lying areas/ lands subjected to water logging Establishment of proper drainage system for such lands 39 Summary Our tea cultivations will have to be faced to extreme conditions in future as a result of CC. Soil degradation, incidence of pests and diseases, bush debilitation and death etc could be occurred at a greater extent than at present. Hence, the most appropriate adaptation strategies should be followed to avert the adverse effect of heavy rains and drought Some of the uneconomic tea lands in the vulnerable areas may have to dealt with crop diversification 40 20

21 -The End- Thank you 41 21