Potential maize yield realization and related driving factors in four typical soils

Whether or how soil conditions limit maize (Zea mays L.) yield is an increasingly important scientific research field. In this study, 4 typical soil types in 4 main maize production regions in China (the black soil region in Northeast China, black loessial soil region in the Loess Plateau, fluvo-aquic soil region in North China Plain and the purple soil region in Southwest China) were analyzed to demonstrate whether and how soil conditions limit maize potential yield realization. The results showed that in all the 4 experimental sites (852-farm in Heilongjiang Province, Changwu in Shaanxi Province, Wenxian in Henan Province and Jianyang in Sichuan Province), maize yields under the best management practices were 10.7 t·hm^-2, 14.1 t·hm^-2, 9.2 t·hm^-2 and 6.7 t·hm^-2 in 2009, which were 92%, 104%, 84% and 78% of yield potentials in the respective regions. Correlation analysis showed that soil physical property (bulk density) and root dry matter density were significantly negatively and positively related with realization degree of potential yield, respectively. Soil physical property (bulk density) and fertility (organic matter) had significant effects on maize potential yield realization. A moderate bulk density and high organic matter content of 69.3 g·kg^-1 under tillage conditions were beneficial to roots growth, and furthermore, led to 92% yield potential realization in the 852-farm, Heilongjiang Province. Low soil bulk density of 1.15 g·cm^-3 under tillage conditions led to the highest root growth and 104% yield potential realization in Changwu, Shaanxi Province. In contrast, high soil bulk densities, especially in the 10~20 cm soil layer with the highest bulk density of 1.53 g·cm^-3 went against roots growth, and led to only 84% yield potential realization in Wenxian, Henan Province. Low soil organic matter and high soil bulk density in soil profiles led to only 78% yield potential realization in Jianyang, Sichuan Province. It was therefore concluded that different soil quality improvement strategies needed to be adopted in different regions to realize maize yield potential and balanced yield increase over large areas across China.