| With the global agricultural productivity and the increase of global food demand, how to resolve the problem that use of agricultural water? It has become a hot issue which agriculture, ecological, environment and other circles should pay more attention. In China, as the main body of the Loess Plateau, the northwest dry-land is a most serious dry farming region. Because of the capacity of storage moisture and the fertile soil, the soil condition is formed,"upper is dry, lower is wet". How to fully use the deeper moisture of the Loess Plateau in dry farming region, improving the use of water efficiencily are still worth researching. This paper want to use the own drought-resistant mechanism angle and combined with fertilizers explore crop how to use the deep water against bad environment in the upper dry soil,for arid and semi-arid region promoting water and fertilizer coupling,stable yield and efficient, opened up new thinking and new way. We hope the drought appraisal index or breeding index can provide certain scientific arguments.The experiment is based on "different moisture and nutrient conditions can affect the root growth and hydraulic lift of the variety winter wheat ". In order to study the effects of fertilization depth on the growth ,yield and hydraulic lift of winter wheat under two different water stress conditions, a two-layer root pot (20cm height of the drier, upper layer, and 40cm height of the wetter, lower layer) was established at a drought-resistant (Changwu 134)and water-sensitive (Xinong 979)wheat variety which were chosen in the study ,through the Time Domain Reflectometry (TDR) to control soil water content of upper and lower layer.Main research conclusion as fallowing:(1)The fertilization depths had significant effects on the biological character and biomass of two varieties winter wheat under two different water stress conditions. To drought-resistant wheat variety, CW134, under same water stress level, effective tiller and leaf area both are most when the fertilizer was applied in the lower soil layer, followed by in the upper layer, and then was no fertilizer application treatment; but the plant height and biomass both are highest or most when the fertilizer was applied in the upper soil layer, followed by in the lower layer, and then was no fertilizer application treatment; under two level water stress condition, the plant height, leaf area of water-sensitive wheat variety were significantly lower than the drought-resistant wheat variety.( 2 ) Under fertilization conditions, to drought-resistant winter wheat variety CW134 ,root length, root surface area and root volume under moderate water stress level are slightly higher than the heavy water stress level; Judging from fertilization depth, to CW134 under the same water stress condition, root length, root surface area , root volume and root weight were highest when the fertilizer was applied in the upper soil layer, followed by in the upper layer, and then was no fertilizer application treatment; but different depths fertilize also significantly increased root length, root surface area ,root volume and soil allocation proportion in fertilization soil layer. Under the same water conditions, compared with XN979, the root length, surface area, and volume of drought-resistance wheat variety (CW134) were significantly increased.(3)Observation on soil water content found that drought-resistant variety wheat (CW134) from the first day 23 p.m. begin to rise, till the next morning between 1 a.m. and 5 a.m.has maintain a high level, then falling rapidly. But water-sensitive wheat variety (XN979) only in a short time has a short time peak (3 a.m.and1a.m.), then began decline rapidly.(4)Result shows that the trend line is about the hydraulic lift of two varieties winter wheat at the different wheat growth period. This line is a single peak shape. The peak in no fertilizer application treatment is highest in filling stage; in fertilizer application is highest in Blooming stage. The whole growth period water of hydraulic lift showed that: RML﹥RMU﹥RDL﹥RDU﹥SMU﹥SDU﹥RD﹥RM.At the same time,which RML treatment in the whole growth stage water of hydraulic lift up to 492.38 g,it was 2.49 times than the minimum (RM treatment). Water use efficiency is highest which the fertilizer was applied in the lower soil layer, followed by in the upper layer, and then was no fertilizer application treatment. Overall, compared with heavy water stress level, under moderate water stress, hydraulic lift is strong , yield is higher,but water use efficiency is still low.(5)Fertilization depth and variety were different effect on each organ of winter wheat nitrogen, phosphorus cumulant. Overall, winter wheat different organs nitrogen cumulates appearing: Gain﹥Stem﹥Leaf﹥Glume﹥Root, on average is 427.78,58.68,53.52,44.62,21.79 mg/column. Phosphorus cumulant appearing: Gain﹥Glume﹥Stem﹥Leaf﹥Root, on average is 65.59,2.95,2.18,1.70,1.50 mg/comumn.(6)Compared with moderate water stress, heavy water stress different degree of reduced the grain and the ground of total nitrogen, phosphorus accumulation, but the effects of various organs are different. Fertilizer processing significantly increased winter wheat grain and leaf of n cumulant, but fertilizer depth is not having obvious influence. And grain and the ground of total nitrogen accumulation, under moderate water stress, when the fertilizer was applied in the upper soil layer is higher than applied in the lower layer; but under heavy water stress, when the fertilizer was applied in the lower soil layer is higher than applied in the upper layer. Form varieties winter wheat angle, To drought-resistant wheat variety, CW134, different organs of nitrogen, phosphorus cumulant are higher than water-sensitive wheat variety (XN979). Form distribution proportion angle, under moderate water stress level, compared with XN979, nitrogen and phosphorus distribution proportion of CW134 gain is increased; under heavy water stress level, is declining. |
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