| The Tibetan Plateau,known as the "third pole" of the earth and the water tower of Asia,is one of the areas most affected by climate change.Its special geographical location and topographic characteristics make it a hot spot in the study of global climate change.Since the late 1980 s,the warming trend of the Tibetan Plateau has been obvious,and the range of warming is higher than that of other regions in China.Climate conditions change from warm-dry to warm-wet,extreme high temperature events increase and extreme low temperature events decrease.Climate change,mainly warming,has improved local heat resources,thus increasing the area of land suitable for cultivation on the Tibetan Plateau.Some studies based on remote sensing data and planting suitability models have shown that sufficient agricultural heat resources in this area increase the area of suitable cultivated land and create favorable conditions for farmers and herdsmen to reclaim.At the same time,under the influence of increasing population pressure,farmers and herdsmen in the agro-pastoral ecotone of the Tibetan Plateau have to reclaim to meet the demand for forage.Climate warming causes shrubs to invade alpine meadows,affecting the growth of pasture.Besides,under the influence of the continuous expansion of grazing scale,the state’s policy of forbidding grazing,resting grazing and rotating grazing,the supply of pasture is very short.This leads to the increasing population pressure on farmers and herdsmen.Population pressure has also been considered as one of the reasons for farmland reclamation.However,farmers and herdsmen also have great possibilities not to choose reclamation.The main reasons are as follows: first,China is one of the beneficiaries of climate change(mainly reflected in the increase of suitable cultivation area).Farmers and herdsmen in other beneficiary countries are more likely to adopt intensive cultivated land strategies to increase long-term investment in agriculture;second,with the acceleration of urbanization,the Tibetan Plateau is confronted with both labor migration and rising labor price.As a rational economic man,farmers and herdsmen are more willing to pursue diversification of livelihoods in order to obtain higher income,resulting in the phenomenon of land abandonment obvious;third,most of the arable land in the Tibetan Plateau is saturated and no more land can be reclaimed;fourth,land reclamation requires higher costs(such as additional irrigation).In order to reduce the risk,farmers and herdsmen often choose intensive use of cultivated land instead of reclamation.Under the climate background,the use of cultivated land in the Tibetan Plateau is expanding from the perspective of theory and remote sensing interpretation.Farmers may adopt the strategy of expanding cultivated land,but there is still the possibility of adopting intensive strategy.In addition,with the acceleration of urbanization,farmers and herdsmen in the Tibetan Plateau are increasingly accepting non-agricultural work.So,it is still lack of understanding how farmers and herdsmen balance reclamation opportunities,risks,labor force migration and population pressure brought by climate change.Therefore,it is necessary to study the farmland use decision-making of farmers and herdsmen under the background of climate change and labor force migration,and to analyze the factors affecting farmland use decision-making,so as to provide theoretical basis for enhancing farmers’ resistance to the risks brought by climate change and formulating effective adaptation strategies for farmland use under climate change and agricultural development plans.The Tibetan Plateau,is a typical ecologically fragile area,an important ecological security barrier and strategic resource reserve base in China.The way of farmland utilization should not be neglected.For example,the reclamation of grassland in the agro-pastoral ecotone will also lead to grassland degradation and desertification,which is irreversible.In view of this,this paper takes the the Yarlung Zangbo River,Nyangqu River,and Lhasa River regions,the Pum Qu River Basin,the Yellow River-Huangshui River Valley and Zamtang county as the research areas,and uses 947 household questionnaires in four regions to analyze the farmland utilization decision-making of farmers and herdsmen under the background of climate change and labor force migration,and quantitatively studies the influencing factors of farmland utilization decision-making of farmers and herdsmen.The results show that under the background of climate change and labor migration,farmers and herdsmen mostly adopt the intensive strategy,mainly with long-term investment,and fewer farmers and herdsmen adopt the reclamation strategy.Finally,according to the results of the study,the relevant policy recommendations are put forward.Specifically,the results are as follows:(1)The perception of farmers and herdsmen in the study area is basically consistent with the meteorological station data except the perception of precipitation.Most farmers and herdsmen perceive that the climate conditions are still "warm-dry",and that the snowstorms decrease and droughts increase.In addition,most farmers and herdsmen believe that climate change has not a significant impact on agriculture.(2)Under the background of climate change,with the acceleration of urbanization,farmers and herdsmen are increasingly recognized for non-agricultural work,coupled with government control,making the phenomenon of reclamation not universal.Only 18.16% of the farmers and herdsmen have reclamation behavior,and most of the area of reclaimed land is between 0.02—0.20 hm2.Through the analysis of the survey data,it is confirmed that the reclamation of farmers and herdsmen is the result of climate change and population pressure.The econometric results also show that there is a significant negative correlation between farmers’ and herdsmen’s reclamation decision-making and their annual income per capita.(3)The level of mechanization in the study area is relatively high,reaching more than 70%.Farmers and herdsmen mainly purchase agricultural tractors and mechanical ploughs,but invests less in micro-tillers and pumps,and most farmers and herdsmen buy agricultural equipment after 2000.At the same time,farmers and herders’ income from non-agricultural activities has promoted the mechanization of local farmland.In addition,the econometric results also show that there is a significant positive correlation between the mechanized investment of farmers and herdsmen and their perception of the overall change trend of spring frost and the number of livestock.(4)The irrigation level of cultivated land in the study area is relatively high,and furrow irrigation is the main method.Irrigation plots are small,ranging from 0.02 to 0.30 hm2.Most irrigation facilities are built by the government,while the investment of farmers and herdsmen in irrigation is relatively low.The main reasons promoting their own investment in irrigation are the perception of overall change trend of frost in spring and the average area of farming plots,while the high per capita monthly income inhibits farmers and herders’ investment in irrigation.(5)The majority of farmers and herders’ independent fertilizer input basically did not change,only 28.83% of farmers and herders’ fertilizer input increased.The results show that the decision-making of increasing fertilizer input by farmers and herdsmen is negatively correlated with their perception of winter duration,precipitation and dependency ratio,and positively correlated with their perception of spring frost,the number of livestock,the distance from residence to town,and the average area of farming land. |
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