Biomass production and carbon sequestration potential of Apple based agri-horti-Pastoral systems under temperate conditions of Kashmir valley

Abstract

Carbon sequestration potential of agri-horti-pastoral systems under temperate conditions of Kashmir valley was evaluated with five treatments viz:Apple +Lucerne (T1), Apple +Beans-Pea (T2), Apple +White clover (T3), Apple +Orchard grass (T4) and Apple + natural sward (T5). The experiment was laid in an established apple orchard of about 20 years of age at Sher-e-Kashmir University of Agricultural Sciences and Technology at its Shalimar campus. A single row of six (6) trees per plot (net-cropped area of 81 m2) was replicated thrice for each treatment with tree to tree spacings of 4.5 m. The highest fruit yield was recorded in Apple +White clover (24.2 kg/tree or 14.76 t/ha and 6.41 kg/tree) followed by Apple +Beans-Pea (22.16 kg/tree or 13.51 t/ha.). The control (Apple + natural sward) yielded lowest fruit yield 3.5 kg/tree or 2.13 t/ha. The maximum green fodder yield was observed in Apple + Lucerne (13.09 t/ha). Maximum biomass allocation (on dry weight basis) was recorded in stem portion of apple trees followed by tertiary, primary and secondary branches. The treatment Apple +Orchard grass gained maximum tree biomass (27.66 kg/tree).Total biomass and carbon stock of the system (tree+crop+fruit) was estimated and Apple + Lucerne (T1) gained maximum total biomass 31.54 t/ha and carbon stock 14.19 t C/ha. The control treatment (Apple +natural sward) recorded minimum total biomass 22.77 t/ha and carbon stock of 10.24 t C/ha. The values of control remained at par with Apple +white clover. The total biomass removed from the system included fruit yield, fruit drop, fuelwood (pruning) and crop biomass of perennial fodders (above ground) except for Beans-Pea where the entire plants were removed along with roots at harvest and were assessed. Maximum biomass 10.31 t/ha and carbon 4.63 t C/ha was removed from treatment (T1) Apple +Lucerne closely followed by Apple + Beans-Pea (9.77 t/ha and 4.39 t C/ha). The control (Apple + natural sward) recorded minimum biomass (5.07 t/ha) and carbon stock (2.28 t C/ha) that was removed. Consequently, the Apple +Lucerne (T1) registered highest amount of carbon sequestered i.e., 9.56 t C/ha and Co2 equivalent of 35.08 t/ha. Our study revealed that treatment (Apple +Lucerne) would conserve 1.02 million tons of carbon and 3.76 million tons of Co2 equivalent.