| According to the actual problems of low field seedling emergence rates,low quality group structure,unmatched balance between the water management and the wheat growth,low water use efficiency and so on with continuous rotary tillage in winter wheat production in lime concretion black soil,a split plot field experiment of two kinds of tillage methods(RT and SS)as the main treatments and three kinds of water treatments(no irrigation: W0;1 water irrigation at jointing: W1;2 water irrigation at jointing and anthesis: W2)as the secondary treatment with variety Zhoumai 27 was set up to investigate the effects of the main effects of tillage and irrigation and their interaction on the canopy structure,microenvironment and yield formation of the winter wheat,then find out the combination mode of tillage and irrigation for simultaneous improvement of yield and water use efficiency.The main results are as follows:1.Effect of tillage methods and irrigation frequency on water utilization of winter wheat in lime concretion black soilTillage and irrigation have obvious regulating effects on soil water content,soil storage water consumption,water consumption characteristics and water use efficiency in different soil layers of sand and black soil.Compared to RT,the average water content of each soil layer within one meter soil increased in SS treatment.Under the same tillage conditions,the decreasing amplitudes of average water content in each soil layer from anthesis to maturity in W1 treatment were higher than that of W2 and W0,especially the average water content of deep soil(60 ~ 100 cm)under SSW1 treatment was significantly higher than that of W2 and W0,and the average increase was 2% and 19.62% respectively.Compared to RT,SS could significantly increase total field water consumption and soil water consumption in winter wheat,which was conducive to improving the utilization efficiency of precipitation and irrigation water.Compared to RT,the total water consumption,soil water consumption,rainfall and irrigation efficiency of SS treatment increased by 2.82%,14.73%,6.99% and 7.79% respectively.The increase of irrigation could obviously promote the field water consumption of winter wheat,and the average increase amplitudes of total water consumption of W2 increased to 11.59% and 30.69%compared to W1 and W0,respectively.In addition,the increases of the number of irrigation times and the total amount of water reduced the soil water consumption and soil water use efficiency,and the decrease amplitudes of W2 treatments reached to17.89% and 15.25% compared to W1 and W0.Hence,deep scarification could promote root ligation,expand root growth space and absorption range,which was beneficial to rational utilization of soil storage water and natural precipitation,which could be used as the main tillage technique for high efficient utilization of water in winter wheat production in lime concretion black soil.2.Effects of tillage methods and irrigation frequency on canopy characteristics of winter wheat in lime concretion black soilUnder the same irrigation treatments,the LAI value of SS treatment was greater than that of RT,and the average growth rate was 7.44% ~ 16.83%,indicating that deep scarification was beneficial to LAI,and it could maintain the duration of green leaves and increase the accumulation of photosynthetic materials.The LAI values of different irrigation treatments under the same tillage condition were W1 > W2 > W0,and the average increase amplitude of W1 was 4.97% ~ 23.28% and 13.47% ~31.96% compared to W2 and W0,respectively.deep scarification plus jointing stage irrigation treatment(SSW1)could effectively maintain long leaf green duration at late growth stage,maintain a larger LAI value,and slow down the leaf senescence process of winter wheat.The average leaf tilt(MTA)varied with different tillage treatments at different growth stages.The MTA before heading showed RT > SS,W0 > W1 > W2,and the peak value decreased rapidly after heading.The decreasing amplitude of the peak showed RT > SS,W0 > W2 > W1.From jointing to heading,it was a sensitive period for wheat in water demand.MTA tended to stand upright with the increase of irrigation water.After heading,with the increase of water and rainfall,W2 treatment was not conducive to the growth of canopy leaves,but W1 was beneficial to keep the new and old alternation of canopy leaves.This indicated that the combination of suitable irrigation and deep scarification was favorable for postponing the decline of new erect leaves and the decline of old leaves.3.Effects of tillage methods and irrigation frequency on canopy microenvironment of Winter Wheat in lime concretion black soilUnder the same tillage,the concentration of CO2 in the canopy of W2 and W1 was significantly higher than that of W0,showing W1 > W2 > W0,and the CO2 concentration of SS was significantly higher than that of RT under the same irrigation mode,and the CO2 concentration in the upper layer,middle layer and lower layer of the canopy showed different and fluctuated,influenced by many factors.Under the same irrigation conditions,the canopy temperature of winter wheat in SS treatment decreased compared to that of RT treatment,and the average decrease was 2.45% ~6.29%.Under the same tillage,the canopy temperature of each irrigation treatment was W0 > W1 > W2.W0 increased by 1.08% ~ 2.90% and 3.45% ~ 6.15%respectively compared with W1 and W2.In the middle and later stages of grain filling,the canopy temperature of W1 increased slowly compared to that of W2 and W0.It showed that deep scarification and proper irrigation could maintain the soil moisture required for wheat,prolong the duration of the green leaves,reduce the temperature of the soil,promote the growth of the leaves,and cause the canopy temperature to decrease.The canopy humidity was opposite to the temperature change,showing SS >RT,and the humidity increased with the increase of irrigation frequency and irrigation amount,showing W2 > W1 > W0.It showed that with the increase of temperature and humidity,different irrigation treatments could improve the field microclimate such as canopy temperature and humidity.4.Effects of tillage methods and irrigation frequency on canopy photosyntheticcharacteristics of Winter Wheat in lime concretion black soilcultivation and irrigation have obvious effect on the net photosynthetic rate(Pn),transpiration rate(Tr),intercellular CO2 concentration(Ci)and stomatal conductance(Gs)of the flag leaf of winter wheat in lime concretion black soil.Under the same irrigation,except for Ci,the Pn,Tr and Gs values of flag leaves in SS treatment were higher than those of RT treatment in the whole growth period.Under the same tillage conditions,the Pn,Tr and Gs values of flag leaves were W1 > W2 > W0 compared with the three irrigation treatments.It showed that the combination model of deep scarification and proper irrigation could effectively slow down the decrease of Pn,Tr and Gs in the flag leaves of the late growth period,increase the transpiration rate of wheat plant,enhance photosynthesis and promote the transformation of photosynthetic material.5.Effects of tillage methods and irrigation frequency on Yield and its components of Winter WheatCultivation and irrigation had obvious regulating effect on grain yield and its component factors of winter wheat.The yield of W1 treatment under the two tillage methods was higher,and the combination yield of SSW1 treatment was the highest,and the average increase of RTW0 treatment compared with the lowest yield was21.07%.Under the same tillage,with the increases of irrigation water and irrigation times,the 1000 grain weight decreased and the spike number increased.The grain number per spike showed difference in two years.In addition to the RT treatment in the year 2015-2016,the grain number per spike increased first and then decreased with the increase number of irrigation times and irrigation total.The cultivation method mainly affected the final yield by regulating 1000 grain weight,and the irrigation mainly regulated the spike number and 1000 grain weight,and then affected the yield.However,excessive irrigation would reduce grain number per spike and1000 grain weight.The interaction between tillage and irrigation was not obvious. |
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