Analysis of climate resource changes during maize growth period inNingxia under SRES A1B scenario

Maize is one of the three main food crops in Ningxia and is widely cultivated in central arid and south mountain zones; where maize is mainly cultivated under rain-fed conditions and with significant influence of climatic conditions. Climate change has adversely affected local agricultural production in Ningxia and several other studies have reported even further adversities under SRES A2 and B2 scenarios. Also climate change has reportedly led to temperature and precipitation anomalies in Ningxia. This study therefore analyzed the impact of future climate change on maize production under moderate emission scenario. The analysis was based on revised data of the PRECIS regional climate model simulation under SRES A1B scenario. The data included changes in average temperature, maximum temperature, minimum temperature, ≥10 ℃ effective accumulated temperature and precipitation for the periods from April to September of 2011-2040 (for the 2020s), 2041-2070 (for the 2050s), 2071-2100 (for the 2080s) and 1961-1990 (the baseline period of climate). In the first step, the study analyzed the distribution of climatic factors in Ningxia for the baseline period and compared that with observed data for the same period. This was followed by distribution and variation analysis of 5 climatic factors for the 2020s, 2050s and 2080s under A1B scenario. These future values minus those of the baseline period yielded the changes in the climatic factors, where precipitation was specifically expressed in anomaly percent. In the final step, climate change during maize growth period was discussed for the future scenarios. The results showed that simulated average temperature, maximum temperature, minimum temperature and ≥10 ℃ effective accumulated temperature were generally lower than the observation values. However, the simulated distributions were similar to the actual situation; i.e., temperatures were high in the north and low in the south. Also while simulated precipitations for relatively large regions were higher than observation values, the simulated and observed precipitation distributions were similar. Overall, the simulated climatic factors reflected the observed conditions in Ningxia. Average temperature, maximum temperature, minimum temperature, ≥10 ℃ effective accumulated temperature and precipitation for the 2020s, 2050s and 2080s were higher than those of the baseline period and the gaps also widened with time. In south Ningxia, maximum temperature intensely increased while average temperature, minimum temperature and ≥10 ℃ effective accumulated temperature more or less increased in north Ningxia under the scenario simulations. Also precipitation increased in the north and decreased in the south of Ningxia under the scenario simulations. The future scenario analysis showed that maximum temperature and precipitation respectively increased and fluctuated with high likelihoods of extreme hot weathers, droughts and floods. Climate change in the future scenario facilitated maize production in the north irrigation zone of Ningxia, especially increase in ≥10 ℃ effective accumulated temperature provided additional heat for higher maize production. In the south mountain zone of Ningxia, however, limited precipitation negatively affected rain-fed production of maize despite any positive effect of increased temperature on maize production. This paper put forward and discussed appropriate countermeasures for crops production in the rain-fed condition.