Changing crop biodiversity and resource use efficiency of traditional versus introduced crops in the cold desert of the northwestern Indian Himalaya: a case of the Lahaul valley
This paper studies the crop biodiversity and its changing patterns across an altitudinal gradient of three highland village agroecosystems: Hinsa (2700 m), Jahlma (3000 m) and Khoksar (3200 m). It also deals with energy (kilocalorie (physiological); kcal or Megajoules; MJ) and monetary (Indian rupee; Rs) efficiency of traditional crops versus recently introduced cash crops in the cold desert of the Lahaul valley. Newly introduced cash crops like hop, pea and potato have drastically reduced the crop biodiversity along the increasing altitudes. Of the total cropped area, ∼70% is occupied by these cash crops. Organic manure, mainly derived from forests and night soil, accounted for 90 and 77% of the total energy input in traditional and introduced cash crops in all the three selected villages, respectively. The energy output/input for traditional crops ranged in Hinsa from 0.6 (Kuth (Sausurea lappa, family Asteraceae) — a root crop of medicinal use) to 6.1 (amaranths); for the introduced cash crops it varied from 0.9 (potato) in Hinsa to 2.8 (pea) in Jahlma. In terms of energy, traditional crops are richer and more viable than the introduced cash crops. Monetary output/input of traditional crops was 0.8 (maize) to 11.8 (Kuth) and for introduced cash crops it was from 1.8 (potato) to 6.2 (hop). Overall, the average monetary efficiency of introduced crops was higher than that of traditional ones. Taking the average of the three villages, the energy and monetary output/input for the introduced cash crops was 1.4 and 3.3, respectively. However, for the purpose of food security and environmental conservation there is a need to establish a balance between traditional and introduced cash crops. This will make farming sustainable in the cold desert environment where crop growth period is limited. The Lahaul valley is landlocked and due to heavy snow deposits at Rohtang pass (3978 m), its main entry from Kullu valley remains accessible only for 5 months (July–November).