Climate resilience in litchi (Litchi chinensis) orchards in Bihar through soil manipulations Kumar Gopal1,*, Tewari Girja2, Kumar Vinod3, Pandey S.D.3, Nath Vishal3 1ICAR-Indian Institute of Soil and Water Conservation, Dehradun 2GBPUAT, Pantnagar, Uttarakhand 3ICAR-NRC for Litchi, Musahari, Muzaffarpur, Bihar *E-mail: gkcswcrti@gmail.com
Online published on 9 October, 2018. Abstract Climate change is being evidenced in form of increased uncertainties and extremities of weather including heat waves and drought. Litchi is a subtropical fruit by origin and natural abundance. Litchi being cultivated on the fringe of tropics and subtropics in India is very sensitive to further warming. The event of drying of litchi tree in some orchards in Muzaffarpur district of Bihar, India during 2016 warranted the need to explore management options to induce climate resilience. Litchi orchards including those where drying of litchi tree was observed were identified and grouped based on different management practices. Soil analysis revealed that pH ranged from 7.8 to 8.3 where as EC was < 0.2 dS m−1. Across the different management practices, available nitrogen was in the very low category ranging from 74 kg ha−1 to 210 kg ha−1. Available P was in the range of 7 to 10.2 kg ha−1 and available K in the range of 98 to 218 kg ha−1. Micronutrients viz., Zinc, was deficit in soil where as Boron and Sulfur were found adequate in most of the orchards. Soil moisture, permanent wilting point (PWP) and soil temperature at the depth of 5 and 15 cm revealed extreme soil dryness and high temperature, relatively less under orchards receiving FYM or, pond sediment. Soil moisture in the orchards was near the PWP where as soil temperature (5 cm) in open was 41 to 42%°C. Very poor rainfall (5.6 mm) between Oct 2015 to April 2016, shallow soil, extreme dryness led break in capillarity between upper soil and lower sand layer, elevated soil temperature coupled with moisture stress were established as reasons for drying of Litchi trees. Under similar soil depth, no drying of trees was observed from the orchards in which either FYM was applied on annual basis or incorporation of pond soil in root zone was routine practice which was corroborated in terms of better moisture and temperature conditions during April, 2016. More events of extreme dryness during October to April were witnessed in post the year 1980 in historical weather data. Climate change projections under representation concentration pathways (RCPs) 8.5 indicate rainfall reduction of about 76% in November to April, though annual rainfall is likely to increase by 36%. Temperature increase to the tune of 2.9 to 4.3°C by 2070, more during April coupled with reduced rainfall poses very high risk on litchi cultivation in traditional belt. Therefore soil manipulations including regular application of FYM, incorporation of pond sediment in orchards on shallow soil, litchi leaf mulching, early irrigations are recommended for moisture and thermal buffering thus greater climate resilience in litchi. Top Keywords Climate change, Litchi chinensing, Soil temperature, Soil moisture, Climate resilience. Top |