Research On Relationships Between Planting Patterns And Annual Water Use Efficiency In Winter Wheat And Summer Soybean

The experiment was conducted in agronomy experimental station of Shandong Agricultural University from 2008 to 2010. The objective of experiment was to investigate the effect and value in production of planting patterns on annual water utilization in winter wheat and summer soybean farmland. The winter wheat experiment consisted of 3 planting patterns and 3 irrigation schedules under the same plant population density (1.8×106 plant·hm-2). Row spacing were 25 cm, 20 + 40 cm for flat planting pattern and 20 + 40 cm (double lines in the furrow with 20 cm spacing, and 40 cm between furrows) for furrow. The three irrigation schedules were used at jointing, heading and filling stages respectively; the amount of irrigation was 30 mm, 45 mm and 60 mm every time. The summer soybean consisted of 3 planting patterns under the same plant population density (3.09×105 plant·hm-2). The row width set at uniform row with 30 cm , narrow-wide row with 20 + 40 cm and 20 + 40 cm (double lines in ridge with 20 cm spacing, and 60 cm between ridges) for ridge. The results indicated that planting patterns could affect the crop yield and water use efficiency (WUE), improve the dynamics of population developmentally, characteristics of physiological and ecological and water consumption. The results were as follows:1. Effects of crop plangting patterns on population develop dynamicsIn winter wheat experiment, the number of tiller of the uniform row and narrow-wide row pattern were significantly higher than the furrow pattern, but growth and development of plant individuals stimulated on the furrow pattern, the leaf area index (LAI) of the furrow pattern increased by 12.47% and 7.25% than that the uniform row pattern respectively. Irrigation significantly effected on development of winter wheat. The high tillers or LAI and total dry matter accumulation of wheat can be achieved in northern China by increasing irrigation amount under uniform planting-density conditions. In summer soybean experiment, the pod weight of the ridge pattern was significantly higher than those of uniform row and narrow-wide row patterns. LAI, total dry matter accumulation and the weight of pod increasing with pre-sowing soil moisture.2. Effects of plangting patterns on farmland microclimate The furrow pattern could increase PAR penetration ratio, decrease reflection ratio, and significantly improve the efficiency of utilization rate of sun light. Irrigation improved the field environment, not only improved the utilization of light and air relative humidity, but also reduced the field air temperatures of 5 cm and soil temperature of 5 cm. Consequently, the furrow pattern could keep a cool and humid environment conducive to the crops for environmental protection against dry and hot wind and intimidation.3. Effects of plangting patterns on leaf physiological characteristicsThe furrow pattern and narrow-wide row pattern increased the water use efficiency of the flag leafs, net photosynthetic rate and chlorophyll fluorescence parameters. Irrigation could significantly increased leaf relative water content (RWC), water potential (Ψw) and chlorophyll fluorescence parameters. All the physical parameters are increase with increasing of irrigation amount, In summer soybean experiment, RWC,Ψw, photosynthesis parameter and chlorophyll fluorescence parameters were the ridge pattern > the uniform row pattern > the narrow-wide row pattern. The RWC, net photosynthesis rate (Pn), chlorophyll content index andΦPSⅡof the 135 mm and 180 mm treatments were significantly higher than that of the 90 mm treatment, but there was no significant difference between135 mm and 180 mm treatments.4. Effects of plangting patterns on the law of water consumption andThe furrow pattern could improve soil moisture at different soil layer, and reduce evapotranspiration of field in winter wheat. In summer soybean experiment, the ridge pattern could improvesoil moisture at shallow soil layer. The 135 mm and 180 mm treatments could keep shallow soil moisture at a higher level, but differs little in 40–60 cm. The WUE of winter wheat were the furrow pattern > the narrow-wide row pattern > the uniform row pattern, the narrow-wide row and furrow pattern treatments were 5.24% and 6.40% higher than the uniform row treatment, and there were no significantly difference between narrow-wide row and the furrow pattern(P<5%). The 135 mm treatment in winter wheat could take advantage of the soil moisture effectively and improve the WUE of summer soybean. The result of correlation analysis showed that there were significantly negative between WUE and total water consumption, irrigation amount of winter wheat, and correlation coefficients were -0.749* and -0.894** respectively. Planting patterns and irrigation had obvious effect on WUE. 5. Relationship of plangting patterns, yield, WUE and RUEThe study found that the evapotranspiration of field, yield, annual WUE of the furrow (ridge) pattern were higher than those of the other treatments. The decreasing the number of kernels per ear and 1000-kernels weight (winter wheat) or productive pod number of main stem and seed number of branch(summer soybean) could decrease crop yield. Irrigation effected on evapotranspiration of field, yield, annual WUE of winter wheat_summer soybean. The evapotranspiration of field and yield could improved with increasing of irrigation amount. The annual WUE of 135 mm treatment was 5.49% and 10.28% significantly higher than those of 90 mm and 180 mm treatments (P<5%). The analysis of variance showed that planting patterns and irrigation had significantly interactive effects. In conclusion, on this testing condition, the furrow treatment of winter wheat and the ridge treatment of summer soybean under the irrigation amount of 135mm of winter wheat were the optimal planting patterns.