湖南省地形因素对水稻生产的影响

作为一种人工生态系统,水稻的生产受自然条件和人为管理的共同影响。其中,地形因素不仅决定了水稻生长必须的光热等资源的再分配,而且还影响人类的农业管理活动。以中国水稻主产区中地形较为复杂的湖南省为研究对象,基于多种数据,从生态学的“格局—过程”思想出发,讨论了地形因素对水田分布、水稻生长过程及水稻产量的影响。研究发现,地形因素对水田分布的空间格局影响最为明显,对水稻生长过程影响次之,而对水稻产量影响较弱。在各地形因素中,高程对于水稻生产的影响最为突出。研究结果还反映出地形因素造成了湖南省水田分布和热量分配在北部平原地区的不匹配,政府部门应根据区域特征,因地制宜采取措施,提高该地区水稻生产效益。

The effect of terrain factors on rice production: A case study in Hunan Province

Rice is the staple food in China and its production is impacted jointly by natural environment and human activities. In this process, terrain condition not only determines the spatial pattern of environmental factors, such as water, heat and radiation, but also affects the agricultural management measures. Although many studies focused on the impact of one or several specific factors on crop production, few studies investigated the direct influence of terrain condition on rice production. Therefore, we selected Hunan Province, one of major rice producing areas in China with complex terrain conditions, as the study area. Based on the remote sensing data and statistical data, we applied the spatial statistical analysis to explore the effects of terrain factors on the rice production from the following three aspects: spatial pattern of paddy field, rice production process and the final yield. We found that: (1) Terrain has a significant impact on the spatial distribution of paddy filed at both regional and county scales. Most paddy fields are located on the northern plain and central hills where the elevation is generally below 300 meters with the slope less than 9° and relief degree less than 140 meters. Also, the spatial pattern of paddy fields in Hunan is sensitive to surface roughness and slope position. (2) Terrain does determine the distribution of temperature, sunlight and soil, and these three environmental factors consequently have direct impact on rice growth. Additionally, several terrain factors (elevation, slope and surface roughness) are related with the phenological stage of double-cropping rice, especially for elevation, which is closely associated with the planting stage for early rice and harvesting stage for late rice. (3) However, compared with the pattern of paddy field and rice production process, the influences of terrain factors on the rice yield are not so evident except for elevation. (4) There is a spatial mismatch between spatial distribution of paddy field and production resources due to terrain factors: although paddy fields are widespread in the northern plain, the yield in this region is lower than that in the hilly area of central Hunan due to limited heat. Our results highly imply that the managers should guide farmers to choose suitable variety and planting system and allocate rice production resources in the northern plain so as to ensure food security.