| Doing field test of dryland wheat in Northwest A&F University North Campus in Shaanxi xianyang,through cultivation mode that different bunch planting density of processing of wheat. In all growth period of wheat, seedling, and jointing stage, and booting stage, and grout stage, and maturity stage1 determine the water and the nutrient of soil, take different soil layer(including 0-20cm﹑20-40cm﹑40-60cm), measuring the water and nutrient of the soil,including soil available nitrogen ﹑ soil available phosphorus ﹑ soil available potassium.Using the data to do the compared research.The results show that there is a certain influence on soil moisture utilization rate on different cultivation patterns, but not significantly different. Different planting densities have different effects on the growth of wheat,also have some influence on absorption of soil water and available nitrogen, phosphorus and potassium, the results are as follows:1..Different dibbling planting density of winter wheat has different absorption on moisture and nutrient of soil, the period that absorb moisture and nutrients of the soil most is the grain filling stage.In this test we have different row spacing,line spacing and different dibbling grain number.When row spacing and grain number is invariant, with the increasing of line spacing, the competition between the wheat on soil nutrient absorption will become small.When spacing is the same, with the increasing of the grain number,the effects on soil moisture and soil nutrient become bigger; When spacing is invariant, grain number is same, with the increasing of row spacing, the effects on soil nutrient will become small,row spacing is the same, with the increasing of the grain number, the effects on soil nutrient and soil moisture become bigger.2. In this test we selected 18 cm and 22 cm respectively as the spacing. According to the data analysis that compared between different wheat on soil nutrient and soil water in different growth period of wheat, spacing of wheat is 18 cm can absorb more soil water and soil nutrient than spacing of the wheat is 22 cm.In the test we selected 12cm﹑16cm﹑20cm﹑24cm respectively as the line spacing. According to the content of soil water and soil nutrient between different soil layer in different period,we known that the wheat of line spacing is 16cm﹑20cm can absorb more soil water and soil nutrient than the line spacing is 12cm﹑24cm. We selected 8 grain ﹑ 10 grain and 12 grain respectively as the grain number. Through the changes of the content of the wheat soil water and available nitrogen,phosphorus,potassium, the the grain number that absorbed soil water and soil nutrient most is 10 grain.In different growth period 10 grain has lower content of soil water and soil nutrient than 8 grain and 12 grain.3. Under two different levels of spacing, in 24 different density the content of soil moisture and nutrient occurs the lowest point. When the line spacing is 18 cm, the row spacing is 16 cm, sown seeds per bunch should be controlled within 8. When the line spacing is 22 cm,the row spacing is 20 cm and sown seeds per bunch should be controlled about 12. This phenomenon occurs because wheat individuals can use limited resources such as light, water, fertilizer rationally.When the density is too large, even though the individual competition for light, water, and fertilizer is small but population density is too small, so the overall limits, the absorption of soil water and soil nutrient is limited. When the density is too small, wheat competition among individuals became very fierce, restricted individual development,soil water and soil nutrient absorption naturally become smaller.0nly under the conditions of moderate density, individual competition for light, water and fertilizer is small, population density was just good and soil water and soil nutrient absorption is greatest. |
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