Evaluation System Of Culticated Land Productivity Stability In The Agricultural Ecosystem For The Meso-small Scale

Food security is not only the indispensable condition for human survival, but also the foundation of social stability and national development in all the times and over the world. According to the relationship of food safety grade and support, the steady development of cultivated land productivity is a most fundamental pillar in the mid-and micro-scale cultivated systems. Without its steady development, the basic guarantee for food safety and people survival would disappear; the social stability and economic development would be non-existent. In particular, with the China's accession to the WTO and the rapid development of domestic industrialization and urbanization and the large increase of population, the problem of food security is gradually acute and urgent day by day. Furthermore, the meanings of cultivated land production which we always discussed in the past time hadn't been recapitulated by growth or volatility in the new historical condition and developmental environment. Hence, the issue of developmental rule and dominating factors accompanied with predicting development trend of cultivated land productivity became a hot topic in agricultural research nowadays. Based on this, by using the cultivated land of Xiong County in Hebei Province as an example, the research was constructed with beginning of the new feature of land productivity—"stability"to explore and study the evaluation theories and methods for stability of cultivated land productivity in the mid-and micro-scale cultivated systems. The main findings and conclusions were as follows:(1)According to the functional properties of cultivated land ecosystem and the formation mechanism and development characteristic of farmland productivity, the result showed that the stability of mid-and micro-scale cultivated land productivity included two components—trends and volatility. The meanings of stability could perfectly meet the two kinds of land in county scale and field scale (including the agricultural land and the experimental land). Through improvements to the earlier expression model for the stability of regional land productivity, the new expression model were constructed for mid-and micro scale farmland production. Then, the evaluation system for stability of cultivated land productivity was built on using the methods of EMD, remaining method, TFP, RS and so on.(2)It was found that a R trend component and four IMF fluctuation components of grain production in Xiong County during 1949 ~ 2008. Particularly, the course of R trend components was divided by the year of 1978 and 1998 into three phases, i.e. slow development, rapid growth and linger. And its variance contribution reached up to 89.61%, which was the most important contribution for grain production in Xiong County during 1949 ~ 2008. Additionally, the multi-time scale characters of IMF fluctuant components were presented in the 3,7,11 and 30 years time-scales. The variance contribution for total grain output were in the order of IMF2>IMF4>IMF1>IMF3. The maximal variance contribution was 4.43% for IMF2, which was a significantly feature of grain output fluctuant in this period.(3)The development of stability of farmland productivity has gone through the low wandering stage for the 1965 ago, sustainable development stage for the periods of 1965 -1986, gradual fall stage for the periods of 1986 -1991, fast growth stage for the periods of 1991 -2001 and slow recovery stage for the periods of 2001 to now in Xiong County since the founding of China People's Republic. The effect of grain yield on influential degree of grain output and grain sowing area is 72.71% and 26.10% among the 60 years in Xiong County, respectively. However, the latter reduced the stability of farmland productivity as its negative values during the most development stages. The strong and weak mosaic pattern for stability of farmland productivity was showed in the space structure of Xiong County. The Zhugezhuang town had the strongest stability, while the weakest stability was recorded in Xiongzhou town. Moreover, the stability degree for kinds of crop was in the order of corn >wheat>minor cereals.(4)The result also showed that the steady development of farmland productivity was mainly determined by the effective irrigation areas, consumption of fertilizers and technological progress during 1978~2008 in Xiong County. The leading factors were consumption of fertilizers, effective irrigation areas, technological progress, rural labor, crop disaster area and pesticide consumption which covered the influential degree by 57.18%, 31.52%, 16.43%, 4.10%, -5.13% and -4.10%, respectively for trends of land productivity, while the dominant factors were total power of agricultural machinery, pesticides consumption, annual cumulative temperature, fertilizers consumption and annual precipitation which covered the influential degree by 30.77%, 23.08%, 23.08%, 15.38% and 7.69%, respectively for volatility of land productivity.(5)The stability of cultivated land productivity was marked in different development characteristic under the long-term different fertilization in the field-scale land (experimental land). The higher stability and lower stability was observed for all NPK fertilization treatment and imbalanced NPK fertilization treatment, respectively. In particular, the worst stability was showed in N0 and P0 treatment. In the past 13 years, the decrease in stability of wheat yield by 4%~22% accompanied with decrease in stability of maize yield by 2%~ 20% (exception of CK and N0) was observed for the experimental lands because of the integrated function of meteorological factors.