Climate trends and impacts on crop production in the Koshi River basin of Nepal

Abstract

Understanding crop responses to climate is essential to cope with anticipated changes in temperature and precipitation. We investigated the climate-crop yield relationship and the impact of historical climate on yields of rice, maize and wheat in the Koshi basin of Nepal. The results show significant impact of growing season temperature and precipitation on crop production in the region. Rice, maize and wheat cultivated at altitudes below 1,100, 1,350 and 1,700 m amsl (above mean sea level), respectively, suffer from stress due to higher temperatures particularly during flowering and yield formation stages. Responses of crop yields to a unitary increment in growing season mean temperature vary from -6 to 16 %, -4 to 11 % and -12 to 3 % for rice, maize and wheat, respectively, depending on the location and elevation in the basin. In most parts of the basin, we observe warming trends in growing season mean temperatures of rice, maize and wheat over the last few decades with clear evidence of negative impacts on yields. However, at some high-elevation areas, positive impacts of warming are also observed on rice and maize yields. If the observed trends in temperature continue in future, the impact is likely to be mostly negative on crop production in the basin. However, crop production may gain from the warming at relatively higher altitudes provided other conditions, e.g., water availability, soil fertility, are favorable.

Household food security in the face of climate change in the Hindu-Kush Himalayan region

“…These basins provide water not only for agriculture, but also for forestry and fisheries as well as urban and industrial purposes (Sikka and Ringler 2009). Recent studies (Yu et al 2013;Rasul & Hussain 2015;Bhatt et al 2014;Zhen-Feng et al 2013) have revealed that increased incidences of erratic precipitation, floods, dry spells and landslides, attributed to climate change, have led to decline in agricultural productivity and deterioration of food security. This study investigates whether these scientific findings were mirrored in local people's perception of climate change and its impacts on agriculture and household food security.…”

Agriculture and Food Security under Climate Change in Nepal

“…Agriculture is heavily impacted worldwide by climate change, and yield reduction may result in the decline of food security, especially in mountainous areas [1][2][3][4]. Agriculture requires much water for irrigation, and worldwide roughly 70% of the water is used by agriculture [5][6][7], and increasingly so under population growth pressure [8].…”

“…or so, while double cropping is generally limited to areas below 1000 m as.l. [4]. Maize can be successfully cultivated at altitudes up to 2800 m a.s.l.…”

“…but in practice, maize cultivation is largely limited below 2500 m a.s.l. [4,31]. Wheat is cultivated up to altitudes of 3000 m a.s.l.…”

“…Wheat is cultivated up to altitudes of 3000 m a.s.l. [4,31]. Nepal's varied topography and social vulnerability make the country particularly susceptible to climate variations [24,[32][33][34][35][36][37][38], and the country has low adaptive capacity to respond to crop variability under climate change [39].…”