Five Kinds Of Crop Seeds’s Emergence Reaction To Soil Water Stress And Seedlings Countermeasures Of Drought Resistance

Soil drought had become a world agricultural obstacle. Therefore the crop’s characters responsed to water stress became the foundation which innovating farming technology purposefully, promoting high and stable yields agricultural. The purpose of this experimental research was to ensure spring-sown crops seedling safely in the northern arid or semi arid regions of our country. By the method of conducting artificial moisture gradients, based on completely controlled the environment, designed the following three tests: the test of influence on the five crops’s emergence under different soil moisture conditions, the test of influence on flax’emergence under soil moisture and temperature double factors , and the test of effect of corn’s emergence under different soil moisture and sowing density. The experiment studied the relationship mechanism between water stress and five crops seedling and water critical value of emergence resisting soil drought . And And further in allusion to the set production background, the paper put forward the corresponding countermeasures of resisting drought. The results showed that:1. Soil moisture influenced emergence percentage and emergence progress significantly. The processes of five crops’s emergence profile to soil moisture demonstrated 3 kinds of types. that is jump, ascending, and S-curve. When the soil moisture contents was higher, emergence progress presented fast jump type. When the soil moisture contents was lower, emergence progress presented slow ascending type. When the soil moisture was between of them , emergence progress appeared S type. Thus it could be used as discriminant basis if seed emergence affected by soil water stress.2. Cleared five kinds of seeds’s emergence’s moisture-sensitive domain. In sandy chestnut soil flax emergence’s moisture-sensitive domain was from 3.5% to 6.0%, while in meadow chestnut soil was from 9.0% to 15.0%. In sandy chestnut soil hullessoat emergence’s moisture-sensitive domain was from 3.5% to 5.0%, while in meadow chestnut soil was from 9.0% to 16.0%. In sandy chestnut soil maize emergence’s moisture-sensitive domain was from 3.5% to 6.5%, while in meadow chestnut soil was from 9.0% to 12.0%. In sandy chestnut soil millet emergence’s moisture-sensitive domain was from 3.5% to 6.0%, while in meadow chestnut soil was from 9.0% to 12.0%. In sandy chestnut soil kidney bean emergence’s moisture-sensitive domain was from 3.5% to 5.5%, while in meadow chestnut soil was from 9.0% to 13.0%.3. Put forward soil moisture threshold value of emergence security. In sandy chestnut soil, with the seedling quality of standards, hullessoat’s soil moisture threshold value was 5.0%, and flax, maize, millet, and kidney bean were 5.5%. With protecting the flax seedling amid drought as a standard,maize’s soil moisture threshold value were 4.5%, seeding rates should increase to 1.61 times average year. hullessoat’s soil moisture threshold value were 4.5%, seeding rates should increase to 1.33 times average year. Flax’s soil moisture threshold value were 4.5%, seeding rates should increase to 1.61 times average year. Kidney’s soil moisture threshold value were 5.0%, seeding rates should increase to 1.42 times average year. Millet’s soil moisture threshold value were 4.5%, seeding rates should increase to 1.81 times average year.In meadow chestnut soil, with the seedling quality of standards, millet’s soil moisture threshold value was 12.0%, maize’s was 14.0%, and the flax, hullessoat and kidney were 13.0%. With protecting the flax seedling amid drought as a standard, kidney bean’s soil moisture threshold value was 13.0%, seeding rates should increase to 1.0 times average year. Flax’s soil moisture threshold value were 12.0%, seeding rates should increase to 1.72 times average year. Hullessoat’s soil moisture threshold value was 11.0%, seeding rates should increase to 1.33 times average year. Maise’s soil moisture threshold value was 4.5%, seeding rates should increase to 1.81 times average year. Millet’s soil moisture threshold value was 11.0%, seeding rates should increase to 1.80 times average year.4. In moisture-sensitive domain, soil moisture influenced plant height and root shoot ratio significantly. With the increasing of degree of soil drought, the crops’s plant height decreased, height’s variation coefficients were accrescent, homogeneous degree descended. While canopy biomass reduced, seedling were thin and root shoot ratio increased. Eventually they lead to seedlings quality’s decline. In moisture-optimal domain, seedling’s plant height, root shoot ratio changed insignificant.5. Ambient temperature and density of crop had significant influence on crops’s emergence percentage. In this experiment’s condition, warming had a tend to increase flax’s emergence percentage. Increasing density of crop, maize emergence percentage declined observably and maize seeds display crowding effect.6. According to the emergence reaction to soil moisture, in the face of agricultural production in different soil moisture, there were some corresponding countermeasures to seedling safely . When the soil water was below the critical value of soil moisture resisting drought, the way of seedling formation with water and the transplant seedlings with filling water could be used. When the soil moisture was between the soil moisture value and drought resistance critical safety critical value , the way of seeding with water could be used. When the soil moisture was between safety critical value and the optimal value, seeding as normal.