Leaf Water Potential Of Spring Wheat And Field Pea Under Different Tillage Practices And Their Relationship With Environmental Factors

Based on a six years long-term experiment in Dingxi Synthesis Dryland Agriculture Test Station of Gansu Agricultural University, by the method of pressure chamber and dry we monitored leaf water potential and water content of spring wheat and pea in different growing stages under tillage practices. Compare the two crops of water physiological characteristics. Leaf water potential of spring wheat and field pea, relationship between leaf water potential and environmental factors under different tillage practices, and relationship between leaf water potential of crops and yield were studied. In order to explore the best farming models suitable for the region and provide a theoretical basis for the sustainable development of dryland agriculture.1 Conservation tillages can be improved 0～30cm layer of soil water content, which no-till with stubble retention (NTS) of spring wheat and field pea soil water content were the highest in the entire growing stages, and they were significantly higher than conventional tillage(T), increased by 3.58%～25.10%和3.20%～26.87% respectively.2 The leaf water potential of field pea was obviously higher than that of spring wheat, but their daily dynamics was similar to each other during the whole growing stages, it was the highest in the early morning at 6:00, then with the passage of time and began dropped, about at 12:00-14:00 the minimum, after that, it gradually raised again, but at 18:00 the value of leaf water potential can not restored to the level of the morning.3 As for spring wheat, maximum leaf water potential appeared at jointing and heading, followed by booting and flowering, minimum appeared at filling stage. As for field pea, maximum leaf water potential achieved at squaring stage, followed by branching and flowering stages, it was the minimum at poding stages.4 Leaf relative water content of spring wheat was the highest at heading, followed by jointing and flowering, and they achieved the minimum at filling stage. Dynamics of water saturation deficient was just opposite to that of relative water content. Leaf relative water content of field pea under different tillage practices was decreased along with the growing stages; however, dynamics of water saturation deficient was just the opposite.5 In the whole growing stages, leaf water potential of both spring wheat and field pea at 6:00 had significant correlation with 0～30cm average soil water content, whether leaf water potential of spring wheat or field pea under no-till with stubble retention(NTS) had very significant correlation with soil water content. The relationship leaf water potential of spring wheat and field pea under different practices between meteorological factors were different in different growing stages. Leaf water potential of spring wheat and field pea had significant linear negative correlation with air temperature, with solar radiation, relative air humidity and air water potential had the quadratic equation model, and with comprehensive meteorological factors were also a good linear relationship.Path analysis showed that air water potential had the greatest effect on the daily dynamics of leaf water potential of spring wheat, followed by relative air humidity, air temperature and solar radiation. Air temperature had the greatest effect on leaf water potential of field pea, followed by air water potential, solar radiation and relative air humidity.6 Compare with conventional tillage(T), no-till with stubble retention(NTS), no-till without straw cover(NT) and conventional tillage with straw incorporated(TS) increased leaf water potential and leaf relative water content of crops, in which effect of NTS was the most significant. Based on the above analysis showed that no-till with stubble retention(NTS) increased leaf water potential and leaf relative water content of crops to some extent, howerer, osmotic regulation and turgor pressure maintenance could allow crops to achieve high yield.