Corn Jointing Stage Of Different Irrigation Of Their Growth And Development, Lodging Resistance And Yield In The Hilly Area Of Sichuan

In2010, the planting area of maize in China has exceeded rice and wheat, and become the largest crop. High density cultivation becomes an important way to improve yields. The first constraint is the lodging to increase production in high density cultivation. The effectively reduce the lodging of the key measures is to stalk growth and development of water and fertilizer management. There are frequent seasonal drought in hilly areas of Sichuan, irrigation at jointing stage is a main drought-resistant measures, but excessive irrigation can be easy to cause lodging. Therefore, This experiment studies the effects of different irrigation amount at jointing stage of spring maize in Sichuan on lodging resistance and yield, and to investigate the reasonable amount of supplementary irrigation.The following conclutions had been drawed by this study:1. The regression equation in effect of irrigation amount on soil water was y=0.00025x+0.18159(R2=0.9429**), showed positive relationship. The diurnal soil evaporation reduced as time extended, showed positive correlation with irrigation amount.2. There was a significant effect on plant height at stamen-growing stage by irrigation amount, the sequence of plant height was A<B<C<D<E. The diurnal change of plant height was positively correlated to irrigation amount from jointing stage to stamen-growing stage, the plant height of the treatment C reached maximum from stamen-growing stage to the10th day after stamen-growing. The length of stem node in maize was in sequence of the fourth> the third> the second, and the length of stem node increased from ground to ear position. At harvesting time, the regression equation between ear height and irrigation amount was y=62.9766+0.0530x (R2=0.9174**).3. In the period of irrigation, leaf area index was very significantly colerrelated to irrigation amount (R2=0.9837**); The photosynthetic potential was very significantly correlated to irrigation amount (R2=0.9831**); The regression equation between SPAD and irrigation amount was y=0.0207x+37.9139(R2=0.9936**). The leaf area index at stamen-growing stage and filling stage also increased as irrigation amount increased. The photosynthetic potential was negatively correlated to irrigation amount after rehydration, the regression equation between Fo and irrigation amount was y=0.0326x+302.3944(R2=0.9127*), showed significant postive correlation.4. The root dry weight (R2=0.8872*), stem dry weight (R2=0.9984**), leaf weight (R2=0.9901**), and total dry weight (R2=0.9942**) at stamen-growing stage were significantly or very significantly correlated to irrigation amount. The root-shoot ratio at big flare stage increased as irrigation amount nicreased, and there was no regularity between the root-shoot ratio and at irrigation amount stamen-growing stage and filling stage.5. The stem puncture resistence strength in the above ground part of mazie was was in sequence of the second node> the third node> the fourth node. In the period of irrigation, the stem puncture resistence strength firstly increased and then decreased as irrigation amount increased, showed significant difference, the treament C had maximum. After rehydration, the stem puncture resistence strength of all treatemnts had not obvious difference by a period of compensatory growth. The effect of photosynthetic indexes on puncture resistence strength was in sequence of Fo> leaf area index> SPAD> photosynthetic potential> Fv/Fm> Fv/Fo. The sequence of stem breaking resistence was the second node> the third node> the fourth node, the stem puncture resistence strength of all three stem nodes increased as irrigation amount increased in treatments of irrigation and rehydration except for the third node at filling stage, breaking ability was very significantly correlated to irrigation amount (R2=0.9630**). 6. The yield increased with increasing irrigation volume, but the rate of increase graduallyslows. Production contribution in the order ofthe ear length> ear diameter and kernel number per row> grain weight ear row> Bald.7. This test during the processing of dry matter of water use efficiency with the increase of irrigation water and decrease, and grain yield and water use efficiency as yield increases with the increasing. In D treatment namely jointing stage irrigation water for350350m3/hm2conditions can be as low as possible in the reduction of conditions improve water use efficiency.