# Agricultural Evolution: Process, Pattern and Water Resource Effect
###### Contents  
* 1 Introduction
\t* 2.1 Land-use and land cover change
\t* 2.2 The landscape landscape  
The agro-pastoral ecotone of Northern China, as an ecological fragile region, is quite vulnerable to global changes and anthropogenic disturbances [13; 14; 15]. Anthropogenic disturbances including over-reclamation, excessive grazing, over-cutting, and farmland abandonment has generated serious environmental impacts in this region, especially the destruction of grassland ecosystem has constantly drained ES [13; 15; 16]. Large-scale natural ecosystems especially grassland were reclaimed as cultivated land promoting by population increase, climate change, and policy shifts in Northern China, leading to continual changes of land-use distribution in the agro-pastoral ecotone [17; 18]. Grassland in Northern China plays a significant role in servicing social-economics of pasture and ecological development of this region. With the encroachment of cultivated land on traditional pastoral areas, the landscape of balanced pasture ecology has been destroyed [13; 17]. Consequently, it is necessary to deeply understand land-use pattern changes, especially the cultivated land expansion processes for future sustainability. Cultivated land is strongly influenced by human activities [9]. Agricultural landscape stands for the spatial distribution of cultivated land, influencing the stability, vulnerability and productivity of cultivated land [19; 20; 21]. Assessing the historical landscape change and its related land-use changes is necessary for understanding the agricultural evolution processes and its ecological, environmental and water resource effects [21; 22; 23; 24]. As an important type of cropland, paddy field serves over half of the world's population with approximately 15% of the world's cropland [6]. Paddy field also shares the attributes of wetlands as a kind of human-made wetlands [25; 26; 27]. Sharing both attributes of wetlands and cropland, paddy field affects food security, carbon storage, water security, as well as zoonotic infectious disease transmission [27; 28; 29]. Growing on flooded soil, paddy rice consumes a large-amount of water resources, regardless of being irrigated or rainfed rice, which affects local water scarcity [30; 31]. Paddy rice planting contributed to more than 10% of global methane (CH\({}_{4}\)) emissions [32; 33; 34]. In addition, paddy field is a significant habitat for waterful, affecting the spread of disease such as avian influenza virus [27; 35]. Considering the difference between paddy and dry farmland [36; 37], it is vital to monitor and analyze paddy and dry farmland distribution separately. Studies have been monitoring paddy distribution maps at local, national and global scales [27; 38]. Some studies also researched the mutual transformation between these two types of cultivated land. However, few studies linked paddy and dry farmland to different land-use changes, especially in agro-pastoral ecotone. The West Songnen Plain, which is located in the central part of Northeast China, is an important food and agricultural base of China [39]. Located in the agro-pastoral ecotone, land-use change is quite frequent in the West Songnen Plain [17; 40]. Under the effect of global climate warming and human disturbance, cultivated land has spread continuously while the natural ecosystem especially grassland has been shrinking and fragmented in this region in recent decades [17]. Much attention has been paid to land-use pattern, wetland loss, grassland fragmentation, lake and reservoir changes and the influence of these changes on ES in this area [17; 40; 41; 42]. However, previous studies analyzed cultivated land as a whole and did not separate paddy field and dry farmland distribution. Therefore, studies regarding landscape change of paddy/dry farmland and linking paddy/dry farmland changes to other land-use changes are lacking.