Effects of Shading Degree on Storage Rate and Growth of Phoebe bournei Seedlings in Fields

In the research, four shading treatments were set, including the treatments with shading degrees at 0, 40%, 60% and 70%, in order to explore storage rate and seedling growth of annual Phoebe bournei. The results showed that the storage rate is growing upon shading degree. In the research, for example, storage rate reached the peak with the shading degree at 70%, and only 42.2% with shading degree at 0. In addition, seedling height and ground diameter showed extremely significant differences among treatments, and the treatment with shading degree at 60% was the best.

Comparative Study of Rice Morphogenesis with Different Cultivation Methods

[Objective] The aim of this study was to compare the morphological char- acteristics of rice （Oryza sativa L.） with different cultivation methods and investigate the dynamics of organ growth and development characteristics of different rice culti- vars. [Method] Based on continuous field observation and destructive sampling over a growing season, detailed organ morphological data were obtained including leaf length, node number, plant height, tiller number, leaf angle, leaf area and specific leaf weight, to compare organ morphological differences among 4 rice cultivars of Baidao （indica）, Jinnanfeng （japonica）, 9325 （japonica） and 9915 （japonica） with 3 cultivation methods of field planting in Weigang, pot planting in Weigang, and field planting in Jiangpu. [Result] Maximum leaf length of each node gradually increased at the early growth stage and decreased at the later growth stage, the relationship between maximum leaf length and node position can be described by the equations y=a,,-~ and y=ax＋b; node number, growth duration, leaf length and plant height of pot planting rice in Weigang were smaller than that of the other two field planting meth- ods; the relationship between plant height and sunshine duration, plant height and GDD （growing degree days） can be described by the equation y=ax＋b, 19.23 ℃.d of GDD （≥10 ≥-d） and 8.12 h of sunshine duration were required to increase 1 cm of plant height; plant height, tiller number, and leaf area of Baidao were higher than that of the other 3 laponica rice cultivars, but the specific leaf weight and leaf angle were smaller. [Conclusion] Comparison of morphological characteristic differ- ences among rice cultivars is an important way to select water-saving and drought- tolerant rice varieties. In this study, the experimental results can be integrated into a rice functional-architectural model to simulate rice organ growth dynamics in a three- dimensional space, thereby providing reference for selecting water-saving and drought-tolerant rice cultivars.

Coupled Effects of Soil Water and Nutrients on Growth and Yields of Maize Plants in a Semi-Arid Region

Interaction between soil water and nutrients plays an important role in sustainable crop management in semi-arid environments.On the basis of a field experiment conducted from 2000 to 2003,this study examined the coupled effects of irrigation and fertilizers on maize growth and yield in a semi-arid region of northeastern China.In terms of plant productivity,nitrogen fertilizer had the most significant effect followed by irrigation and phosphate levels.The combined application of nutrients and irrigation exerted a synergistic effect on the grain yield of maize plants.Regression analysis indicated that optimal levels of nitrogen and phosphate,in addition to adequate irrigation,could greatly improve the efficiency of grain production.Similarly,optimization of soil nutrient availability substantially increased water use efficiency.These suggested that for the most efficient and sustainable crop production,irrigation and nutrient management should be based on a quantitative understanding of water/nutrients interaction,particularly in semi-arid and arid regions.

Fields experiments in North China show no decrease in winter wheat yields with night temperature increased by 2.0-2.5°C

The trends of daily maximum and minimum temperature in global warming indicated that the daily minimum temperature （Tmin） has risen more than twice as fast as the daily maximum temperature （Tmax） during the 20th century. Most researchers have focused on how the crops respond to daily mean temperature, whereas few controlled experiments were carried out to in- vestigate how the crops respond to the Train rise. In particular, no experiment research has reported on how crops respond to the higher night temperature, which was the main trend in the climate warming. Taking winter wheat as the test crop, we investi- gated how the winter wheat growth and yields responded to the higher night temperature. In the field experiments, infrared heaters were used to increase higher night temperature （HNT） by about 2.5℃ in contrast to the normal night temperature （CK） in two whole growth durations of winter wheat in 2008-2009 and 2009-2010 in North China. The results indicated that, com- pared to the CK treatment, winter wheat yield did not decline in HNT treatment, which increased temperatures by 2.0-2.5℃ in both Wanner year （WY） and Colder year （CY）. Furthermore, winter wheat yield in CY increased significantly in HNT treatment. HNT treatment in CY could significantly promote tillering and increase the effective panicles, which increased grain yield significantly （by more than 30% compared with CK）. HNT treatment in CY contributed to an increase in the effective panicles and Kernels significantly, although making a significant reduction in 1000-grain weight, but did not lead to the yield decline. Under the HNT treatment, the whole growth duration of the winter wheat was shortened and the phenological dates were earlier except for the beginning of overwintering; the beginnings of the overwintering phase were postponed substantially and the ends of the overwintering phase were ahead of date compared to CK, which shortened the duration of overwintering considerably. We draw on our own studies to show examples of higher night temperature impact on winter wheat in a relative- ly cold year and relatively warm year in North China. Our results refer to winter wheat in North China, not all main winter wheat producing regions, in Huang-Huai and Southwest of China. Some uncertainties of our predictions derive from fast pro- gress in crop breeding, the variability of climate, and the role of adaptive actions in the future. As expected, the adaptation measures should be considered to cope with the impacts of global warming on crops, and further research and assessments should be conducted.