Quantitative Analysis On Yield Performance Dynamic Process Of Winter Wheat And Summer Maize And High Yielding Approaches

The winter wheat (Triticum aestivum L.)–summer maize (Zea mays L.) rotation is the main crop system for whole-year high yield in North China plain. Quantifying the two crops yield performance are badly needed for whole year yield increasing. On the basis of the quantitative analysis formula of yield performance MLAI×D×MNAR×HI= EN×GN×GW, different cultivars of winter wheat (Gaocheng 890, Yannong19, Lunxuan 987, Yumai 49, and FS230) and summer maize(Yinong 103, Zhengdan 958, Denghai 601 and Nonghua 0379) were used in field experiments with three different densities and different sowing time and harveat time in Hebei Langfang in 2006-2008, Henan wen couty 2006-2007 and jiaozuo 2007-2008 respectively, and the yield performance parameters and the dynamic process of the two crops for different yield level were quantified. And the main results were as follows:1. With the five yield performance parameters dynamic simulation models for two crops of winter and summer maize, leaf area index and ear number dynamic accorded with the same equation of y= (a+bx)/ (1+cx+dx2), and the Logistic equation y= a / (1+be-cx) could make a good estimation of dry matter accumulation and grain weight dynamic well, but the duration dynamic conformed to y= (ab+cxd)/ (b+xd). Whereas, the values of the above equations had differences among different cultivars, densities, duration and sowing with harvest time and so on.2. The yield performance parameters varied with different densities, cultivars, sowing and harvest time. With the plant density increasing, mean eaf area index (MLAI) and ear number (EN) increased significantly, but the mean net assimilation rate (MNAR), grain number (GN) and grain weight (GW) decreased relatively, which means the yield performance parameters play the collaborative effect on high yield realization. Also higher yield cultivars with higher MLAI, duration (D), EN, GW and harvest index (HI) than the normal yield level.Meanwhile, delaying the sowing time of winter wheat, the MLAI, EN and GN decreased, MNAR, HI and GW were significantly promoted. Similarly, the MLAI, HI, D, andGW of summer maize significantly increased with late harvest.3. The yield performance of winter wheat and summer mazie varied significantly with different yield levels. The yield performance of MLAI, D, EN, GW and HI increased 51.6%, 20.6%, 16.7%, 23.6% and 3.0% respectively when the yield of winter wheat increased from high yield 6000 kg ha-1 to higher yield 9509 kg ha-1. Similarly, the above parameters increased 38.7%, 21.6%, 27.4%, 13.2% and 24.5% respectively when the yield of summer maize increased from high yield 8349 kg ha-1 to higher yield 10530 kg ha-1. In conclusion, the two effective approaches,"structural exploration"and"functional exploration"were were put forward in exploring crop production potential.4. The double late-cropping system with winter wheat–summer maize is important for whole-year higher yields. The yield performance quantitative parameters of the double late-cropping system showed that MNAR, HI, and GW were significantly promoted of winter wheat in the double late-cropping system. Similarly, the MLAI, HI, D, GW of maize significantly increased in the double late-cropping system. The light and temperature use efficiency were 2.22%–10.86% and 0.47%–11.56% higher in the double late-cropping system with 442–2575 kg ha?1 of additional yield than the control. Without any increase cost, based on late sowing of winter wheat, early-maturing wheat cultivars are suggested to be used in the double cropping system in North China, resulting in longer grain-filling period of the following maize crop and ultimately higher yield.