The Effects Of Ploughing Wheat Straw Under Soil On Soil Fertility And Physiological Effects On Resistance Of Winter Wheat Under Wheat-Summer Corn Rotation

As the modern intensive agriculture of china develop,the civilization increase continuously,the infield area decrease continuously result in the soil organic matter content reduce quickly and that the unused soil fertility flow away bring the huge pressure to the soil environment,the crop's ability of anti-senescence and resistence parameters reduce, the crop's yield decrease and the crop's quality deteriorate.The experiments were carried out in Northwest Sci-Tech University of Agriculture and Forestry, Yang ling. The crop planting patters is two crops year; the experiment located the different rates of wheat straw ploughed under soil (okg/hm2, 4500 kg/hm2, 6000 kg/hm2 and 7500 kg/hm2). The content of soil fertility,the consecutive crop's yield,the growth increment of the root system and the senescence parameters of the flag leaves of winter wheat under wheat-summer corn rotation,the winter wheat's yield and the quality were surveyed and measured. Furthermoue, the valuable results and conclusions as follows:1 The yield of consecutive crop (corn) under the different treatmentsThe servey of consecutive crop's yield demonstrate that actual rate of the effect of wheat straw ploughed under soil on corn's yield is not significant , there is a significant yield difference between CK and treatmentⅣ,there is no significant yield difference between CK and treatmentⅡ,Ⅲand there is no significant yield difference in treatmentⅡ,Ⅲ,Ⅳ. The corn yield of treatmentⅠ(CK) is the most and the corn yield of treatmentⅣis the lowest in the all treatments'corn yield.2 The abilities of anti-senescence of winter wheat under wheat-summer corn rotation under the different treatments2.1 The effect of root senescence under the different treatmentsThe experiment indicate that the treatmentⅢ's growth increment of the root system is the biggest and treatmentⅢ's root dry weight bigger than CK on the soil layer of 15～20cm,20～30cm; on the 15～20cm soil layer ,the treatmentⅢ's wheat root TTC reducing capacity is 0.448×10-5 gTTC/g(FW)·h)more than CK's in the flowering stage and 0.949×10-5 gTTC/g(FW)·h)more than CK's in the ripe stage; on the 20～30cm soil layer, the treatmentⅢ's wheat root TTC reducing capacity is 0.231×10-5 gTTC/g(FW)·h)moer than CK's in the flowering stage and 0.939×10-5 gTTC/g(FW)·h)more than CK's in the rape stage.Actual rate of Wheat straw ploughed under soil can remarkably promote root system's growth, increases the distribution of root system in the in-depth soil, and enhance the activity of root system, specially the activity of root system in the in-depth soil;2.2 The effect of senescence of the flag leaves of winter wheat under wheat-summer corn rotation under different treatmentsThe experiment indicate that ploughing actual rates wheat straw under soil could remarkably slow down the declines in the chlorophyll contents and photosynthetic rates, inhibit the reductions in the SOD and POD activities and the increases in the MDA contents in the leaves of wheat plants during senescence so as to delay leaf senescence of wheat during late growth.Ploughing wheat straw under soil had the most favorable effect at the rate of 6000 kg wheat straw /hm2 and the least favorable effect at the rate of 7500 kg wheat straw /hm2.3 Yield of winter wheat under wheat-summer corn rotation under different treatmentsThe winter wheat's yield wae surveyed after the wheat straw plohghed under soil, the conclusion is that there are significant yield difference in all treatments except treatmentⅠ's yield and treatmentⅡ's yield, the treatmentⅢ's yield was the highest,the yield is 7126.2kg/hm2 and the treatmentⅢ's yield was 152.5 kg/hm2 higher than CK and 140 kg/hm2 higher than treatmentⅡ.4 Effects of different treatments on sugger and starch content of winter wheat's grainThe winter wheat grains'content of sugger and starch were surveyed, the conclusion is that actual rates Wheat straw ploughed under soil can accelerate winter wheat grains'content of sugger and starch, and the effect is more significantly as the rate of wheat straw ploughed under soil increased in definite rate of wheat straw ploughed under soil range, the treatmentⅢ's effect is the best.5 Effects of different treatments on soil fertilityWheat straw ploughed under soil can accelerate soil organic matter's accumulation,enhance available phosphorus content and available potassium content quickly,enhance available nitrogen content slowly, the effect of enhanceing soil potassium fertility is best especially, Wheat straw ploughed under soil accelerated the enhanceing of yield.The enhanceing content of the soil surface layer's fertilities are more than other soil layer's comparaly, but as the time of wheat straw ploughed under soil prolonged the underlayer's fertilities enhanced significantly, this means that the effect of wheat straw ploughed under soil on the soil fertilities increased continuously as the time of wheat straw ploughed under soil prolonged.6 The relation between the soil fertility and the flag leaves'physiological parameters of resistanceThe correlations of different resistant parameters with the soil fertility indicated that there are correlations between winter wheat's photosynthetic rates and the content of available nitrogen,phosphorus and, the correlation of available nitrogen and available phosphorus with photosynthetic rates is significant difference; the correlation of available nitrogen content with POD activity,MDA content and soluble protein content is significant difference; The correlations of different resistant parameters with soil available phosphorus content are significant difference; The correlation of soil available potassium content with SOD activity and soluble protein content is significant difference;the conclusion that Wheat straw ploughed under soil raise the soil fertilities and retard winter wheat flag leaves'senescence.The correlations of different resistant parameters with the photosynthetic rates indicated that during the senescence of winter wheat, the anti-aging contribution of different resistant parameters increased in the order of MDA content>solvable protein content>POD activity>SOD activity(with correlation coefficients standing at -0.999**; 0.997**, 0.976* and 0.954*, respectively).