Study On Simulation Model And The Relationship Between Growth Development And Soil Water Content In Peanut

Water test was got in 2007. through controling the soil moisture content on different growth stages,study the connection between peanut photosynthetic characteristics,the dynamic of growth,dry matter accumulation,water use effic- iency of different growth stages and soil moisture content.According to the analysis of the classical growth theory and methods,and established a water control under the peanut growth model.Key findings are as follows:1 The affect of water stress on physiological characteristics and drymatter production of peanutWater treatment on the day peanut emergence to 40d by pot experimen- t,kept relative soil water content in 90%, 70%, 50%, 40%.Compared with 70% suitable soil moisture treatment during treatment,90 % ,50 % of light drought, 40 % of heavy drought treatment decreased the photosynthesis rate(Pn), actual PSⅡefficiency(ΦPSⅡ),optimal/maximal photochemical efficiency of PSⅡin the dark (Fv/Fm), photochemical quenching co-efficient (qP), maximum fluor- escence (Fm) of peanut leaves, increased initial fluorescence(Fo) and nonphot ochemical quenching co-efficent (qNP). The peanut leaf transpiration rate, sto- matal conductance and intercellular CO2 concentrations ,water potential decreased, the membrane permeability and osmotic potential increased with drought . The peanut leaves chlorophyll content gradually increased with the relative soil moisture content lower, but the heavy drought that relative soil water below 40% decreased the chlorophyll content; in the range of 40 % to 90% relative moisture, the trend which peanut leaves chla / chlb was decreasing with lower relative water content. The order that all factors associated with the photosynthetic rate was Fv / Fm> stomatal conductance>ΦPSⅡ> water potential> osmotic potential> root activity transpiration> chlorophyll content in the seedling stage.A pool-culture experiment was conducted to keep relative soil water content in 90%,70%,50% in earlier growing stage,drought reduced the fertility of dry matter accumulation of peanuts, compared with 70% relative moisture content treatment, dry matter accumulation of the 50% treatment decreased in 46.79%;slowed accumulation rate of dry matter , accumulation rate of dry matter of the 50% treatment decreased in 37.02% compared with 70% relative moisture content treatment. Drought in earlier growing stage reduced the plant height, length of lateral branch,the number of the main stem of green leaves and stems,but increased the peanuts branch number.Drought in yield forming period reduced the pod yield and harvest index of peanut, meanwhile reduced the dry matter accumulation per plant. Drought in yield forming period decrea- sed the length of main stem,the length of cotyledonary,reduced the NO.of main stem node , the number of branches, NO.of main stem green leaves , fruit peanut number and leaf area index , therefore it reduced the peanut production.2 The adaptability of peanut on drought stressKeeping 40d water treatment of the pod experiment, Relieveing drought stress, relative moisture reached 90% of all treatment,The drought treatment that keeping the range of 40 % to50% relative moisture , the peanut Pn increased in 13.87%~15.12% compared with 70% relative moisture treatment. When the soil moisture lower to 40 % to50% again, the photosynthetic rate,ΦPSⅡ,Fv/Fm those drought in seedling stage was higher than unaffected by stress still.It showed that peanut had adaptability to drought in seedling stage. index,the pod yield and harvest index increased 2.45% and 9.49% of 50% relative moisture treatment compared with CK;that increased dry matter accumulation amount in late growth stage, at harvest ,dry matter accumulation amount increased in 3.42% and 15.58% of 50% relative moisture treatment compared with 70% treatment and CK;that increased dry matter accumulation rate in late growth stage, dry matter accumulation rate increased in 2.03% and 19.72% compared with 70% treatment and CK; average pod dry matter accumulation rate increased in 7.08% compared with CK;increased 100-pod weight, 100-seed weight and shelling ,reduced the NO. of pods per kg. moderate soil drought in earlier growth was beneficial to increase dry matter accumulation and yield.3 The affect of different soil water content on water use efficiency and water consumption of peanutThe total water consumption of whole growth period,keeping 90 %,70%,50%relative moisture in earlier growth were that 590,450,380mm, keeping 90%,70%,50%relative moisture in yield formulation period were 560,440,340mm, the condition of natural precipitation was 490mm. Keeping 50% relative soil water content in the earlier stage, 70% relative soil water content in the yield formulation period, is conducive management pattern to the realization of efficient utilization of water resources, increasing irrigation amount on the basis, caused water resources wastage.The water consumption of each growing stage showed that pod setting period > pod-pin stage period> Seedling period> full of fruit period; water consumption percentage also expressed similar regularity. Pod setting period was the vigorous stage when peanut uptake water , the soil water content condition was very important to the formation of peanut dry matter, with increasing irrigation amoun, peanut water consumption rate significantly increased in the pod setting period, water consumption percentage also increased significantly. The proportion that stage water consumption to total water consumption of yield and higher water use efficient treatment was that14.7%t for the seedlings, 22.1% for flower-period, 39.5% for podding stage, 23.7 %for the full fruits.Irrigation affected mainly 0 cm ~ 60cm layer soil water containing, the soil water content declined rapidly of 0cm~40cm soil layer after irrigation, evidently, the major water consumption was in this soil layer for peanut ,the relative soil water content below 60cm soil layer changed slightly.4. Simulated model of plant dry matter in PeanutBy measuring the dry matter accumulation and available water content in soil in the three different growth process at their different water fertilizer treatments levels in the test of water fertilizer in 2007.Through regression analysis and curve fitting, dry matter accumulation dynamic accord with S-shaped curve, which can be expressed by logistic equation W = Wm /(1 +ae?bt). Then make use of it to establish respective dry matter accumulation dynamic model for different water fertilizer levels. The derivation of equation is dry matter accumulation rate GR and relative growth rateRGR= GR/W. Make available soil water content for each stage in the three different water levels as variables to set up the fitted equations RGR=f(Wi,dj)= A+B1*Wi+B2*Wi∧2,which expresses the relation between RGR and available soil water content in different growth period. Then get the corresponding parameters A, B1,B2for each period. A, B1,B2 curve fitting with growth process ,so bring in the independent variable of growth period(dj). Then a simulation model for dry matter accumulation relative growth rate is set up: RGR=f(Wi,dj) (Wi is soil water content at different growth stages, dj is growth period). Finally, the dry matter accumulation prediction model is established as W=f(Wi,dj,t)=W0*(1+RGR).