Drivers And Impacts Of Changes In Rice Cropping Systems In The Major Rice-producing Area Of Poyang Lake Plain

The series of No.1 Central Document and other favorable agricultural policies from Central Government have steadily promoted grain production. However, factors such as input costs, labor force and irrigation conditions have led to cropland occupation and abandonment, and frequent fluctuation of rice cropping systems at the regional scale. The major rice producing area in Poyang Lake Plain(PLP)is one of the important rice-producing regions in China, characterized by typical single- and double rice cropping systems(RCS), which are particularly suited for remote sensing monitoring of RCS. It’s important that analysis on RCS changes and its driving forces in the major rice-producing area of the PLP is good for increasing multiple crop indexes, enhance food provision service and safeguard for regional and county security. Investigations on the drivers and impacts of changes in RCS in the major rice-producing area of the PLP will provide guidance to rice production for the PLP and southern China.Taken the major rice-producing area of the PLP as a study area, Landsat TM/ETM+/OLI images in 2005-2013 were used to delineate the spatial dynamics of paddy field and RCS within critical temporal windows based on the rice calendar, cloud coverage percentage of scenes and precipitation data. Meanwhile, 682 valid farmers’ questionnaires focused on the changes of RCS and its driving factors were collected during 2014-2015 across the PLP. Then, Logistic Regression Method was applied to evaluate the impacts of the driving forces on the RCS changes. The results showed that:(1) The middle September and early October could be the time window for the differentiation between single cropping rice and double rice. Specifically, the planting areas of single rice and double rice are 4 426.90 km2 and 5 808.56 km2 in 2013, respectively, indicating that the multiple-cropping index is 156.7%. During 2005-2013, paddy field area decreased 282.40 km2, the planting area for single cropping rice decreased by 788.22 km2, and the planting area for double cropping rice increased by 1 564.45 km2, and the multiply cropping index increased by 9.0%.(2) Spatially, both rice types were distributed across the study area but showing a general distribution feature, namely divided by the line of Ganjiang and Raohe River with single- and double cropping rice in the north and south part respectively. Double-season rice is mostly in the Ganjiang River delta plain and Xinjiang River, while single-season rice is generally distributed around the lowland in the Poyang Lake and periphery of the built up area.(3) 60.4% farmers in the major rice-producing area of the PLP only cultivated double rice, 26.7% farmers just chose growing single cropping rice, and 10.2 % farmer preferred to plant the both. Thus, double cropping rice was still the dominant type, of which 5.4% double rice cropping farmers had to cultivate one season per year, either early rice or late rice due to the lack of water irrigation in the hilly area or water logging in the low-lying area. The total proportion of farming abandonment and farmland transfer and occupation for other purposes reached to 3.7%.(4) The net-income per mu(Chinese unit, one hectare equals to 15 mu) for double cropping rice was higher than that of single cropping rice, about 323.9 Yuan(RMB). However, the ratio of input-output and the rate of profit for single cropping rice were about 15.9% and 115.9 %, respectively higher than those of double cropping rice. Income, irrigation, field quality, labor, national policies and environmental pollution were the driving factors for the fluctuations of rice cropping systems.