In line with the equation of soil moisture balance and the results from field experiments for years, the source and
consumption of soil water components and their calculating models were scientifically analyzed. And based on the wheat
condition in its whole growth and development period, as well as water consumption pattern and soil water stress index,
a computer-based comprehensive study was made for discussing spatial distribution of non-stress soil water content,
field moisture utilization and irrigation mode for winter wheat in different climate years to provide useful suggestion as
to directing irrigation and management. The analysis showed that: no matter under what type of climatic conditions,
winter wheat fields need irrigation at least once in northern part of Henan Province, however, in southern part, especially
the southern area of Huai River, irrigation is needless; cornfields in the middle of the province should be irrigated once in
the years short of precipitation, while not be irrigated in the years with abundant rainfall.
Climate yield potential is known to be under great effect of climate factors. Based on multi-yearly climate records and agrometeorological observations and by means of the scheme for calculating yield potential (YP) proposed by Huang Bingwei the authors investigate the distribution of mean climate YP for several representative stations in Henan and averaged availability of climate resources for staple crops in this province, and with Zhengzhou station as the typical station, calculated is made of annual YP of photosynthesis, light-temperature, and light - temperature- water and also YP of wheat and corn related to the above three factors. Wavelet analysis shows that on an annual basis, the photosynthesis YP has quasi-8 yearly periods, light-temperature YP gives quasi-8 and quasi-4 yearly periods, and light- temperature-water YP exhibits quasi-6 and quasi-10-yearly periods. Study is also undertaken of availability of climate resources by wheat and corn in the year and their growth season. Finally, analysis is done of effects of meteorological factors upon yields of the staple crops as well as their availability of the climate resources.
By means of a linear tendency estimation scheme and correlation analysis a study is undertaken of change in Zhengzhou climate and phonological response of woody plants thereto, together with relations between meteorological elements (rainfall, sunshine length and mean temperature) and phenological periods investigated. And later, using a least squares polynomial, a fit expression is constructed for the peak phase of flowering in relation to mean temperature over the previous 3 months. Results show that mean temperature is the critical climate factor to the phonological response of the trees except for leaf-falling phase in autumn; temperature inference of phenology has a clear ecological implication in exploring the relation between climate change and phonological response, with which to plan agricultural undertaking and monitor ecological environment on a scientific basis.
From the dependence of winter wheat on water for growth a study is conducted of drought intensity and probability as well as their impacts upon the yield, whereupon are developed models for venture evaluation of drought damage to the crop grown in Henan province, with which to make the venture evaluation and regionalization of drought effects to provide scientific basis for modifying crop structure and preparing countermeasures for preventing and alleviating drought loss.
Using data from Zhengzhou the Excel-made time-dependent variations in the growth and development (G/D) stages of winter wheat in 1981-2002 are investigated, with analysis done of the curves. Also, the trends of G/D variations over the years are dealt with by use of the related tendency rates of the appearing dates of all the G/D stages of the crop. Results show that the dates of pre-winter G/D stages depend mainly on the seeding date and the overwhelming majority of the G/D stages shift to an earlier date in the vegetative growth period. A statistical expression is constructed by utilizing the 1981-2002 data of the number of days of the G/D stages and corresponding mean temperatures, with which to explain the variation of the G/D stages of winter wheat.
Based on the relationship between water balance and crop-water, water-saving irrigation model was integrated with monitoring and prediction of soil moisture, forming a system of decision-making of irrigation. It is demonstrated that straw mulching for winter wheat is an effective way to reduce soil evaporation at early stages and increase yield and improve water utilization efficiency. Combination of water-saving irrigation and straw mulching plays an important role in China water-saving agriculture.