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Ma S.,CAS Changchun Observatory | Wang Q.,Institute of Meteorological science of Jilin Province | Lu H.,National Meteorological Center | Xu L.,Agrometeorological Observatory of Yushu County of Jilin Province | And 2 more authors.
Shengtai Xuebao/ Acta Ecologica Sinica

Maize emergence speed and the emergence rate relate to soil moisture and air temperature, and they largely determine the corn growth and yield. In order to obtain the relationships between seedling emergence speed, seedling rate of spring maize (Zea mays) and soil moisture and air temperature respectively, the experiments of water stress and by-stage sowing for spring maize were conducted at an agro-meteorological experiment station in the central part of Northeastern China. In an artificial rain-proof cover, 4 water treatments (not drought, light drought, drought and severity drought) and 3 sowing treatments (early, middle and late) were set to create soil moisture variation and air temperature difference during the period from sowing to germination. And soil moisture, water amount for irrigation, rainfall, air temperature, the seedling stage and emergence rate were observed. The results showed that the relationships between soil moisture and emergence rate, period of emergence both were significantly quadratic function during the periods of sowing and emerging. Below field capacity, the greater soil moisture was, the faster the corn came out and the higher the emergence rate was. Soildrought delayed the period of emergence and decreased emergence rate. Low temperature slowed down the emergence, but had little effect on emergence rate. The equation of relationship between days from sowing to emerging (D), soil moisture (S) at a depth of 0 to 20 cm and average air temperature (T) was D = 63. 450-1. 194S -1. 442T. The equation of relationship between emergence rate (P), S and T was P =5. 107 S +1. 857 T-56. 5. Combinational influence indexes of average soil moisture, effective soil water (H) and air temperature on maize emergence speed were that corn emerged quickly when 25% >S>21%, 70 mm>H>45 mm and T>18°C; it would emerge normally when 21% >S>18%, 45 mm>H> 35 mm and 18°C >T>16. 5°C; and it would emerge slowly when 18% >S>16%, 35 mm>H> 25 mm and 16. 5 °C >T>15. 5 °C; and the emergence was postponed remarkably when S<16%, H<25 mm and T<15. 5 °C. Germination rate depended mainly on soil moisture in this study. The highest germination rate (more than 95%) occurred when S >85% and H > 50mm; the higher one (about 90%) when relative humidity was about 80% and 50 mm>H>40 mm; and the lower one when relative humidity was less than 70% and 50 mm>H>40 mm; and the one was less than 65% when relative humidity was less than 60% and H<30 mm, and the serious drought happened. Source

Wang Q.,Institute of Meteorological science of Jilin Province | Ma S.-Q.,CAS Changchun Observatory | Xu L.-P.,Agrometeorological Observatory of Yushu County of Jilin Province | Yu H.,Agrometeorological Observatory of Yushu County of Jilin Province | Zhang T.-L.,Agrometeorological Observatory of Yushu County of Jilin Province
Journal of Natural Disasters

A field test was carried out for impact of spring drough on seedling growth of spring maize., test included three sowing periods (temperature treatment) and four soil water stress. The results show that in main maize growing areas of central northeast China, quality of seedling growth of maize depends on water. The relationship between the seedling growth of maize (leaf age, biomass and plant height) and spring soil moisture and cumulative effective soil water presents a quadratic function. Drought stress reduces the growing speed of leaves of maize and plant height, decreases the biomass, significantly inhibits the seedlings growth. The indices of spring drought of maize are as follows: value of W(average soil moisture) between 18% -19% or H (accumulated effective soil water) between 45-54mm belongs to light drought; that between 17% -18% or 40-45mm respectively belongs to medium drought; and that below 17% or 40mm belongs to severe drought. Source

Ma S.,CAS Changchun Observatory | Wang Q.,Institute of Meteorological science of Jilin Province | Chen F.,Agrometeorological Observatory of Yushu County of Jilin Province | Xu L.,Agrometeorological Observatory of Yushu County of Jilin Province | And 3 more authors.
Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering

Northeast China is a major production area of spring maize. As the slight change of precipitation in spring, the spring drought for maize is frequent. To establish maize spring drought index and quantitative assessment modes based on maize seeding growth, water stress-sowing date field experiments were carried out in the spring of 2010 and 2011 in a maize product area (Yushu city) of the Northeast China. 4 water treatments (no drought, slight, moderate, severe) and 3 sowing date treatments (normal, relatively late and late, each interval for ten days) were designed in the experiment, and soil moisture controlled by the canopy and artificial irrigation. The soil moisture, maize emergence date, emergence rate, leaf age, plant height, biomass in the range of 7th leaf and yield were observed. The spring drought assessment modes were established by analyzing the response of yield to emergence date and seeding growth with regression method. The results showed that the yield of maize was significantly correlated with the emergence date, emergence rate, seeding height, leaf age and seeding biomass. The relationships modes between the relative yield and relative value of the seedling growth factor most as linear functions. Delayed seeding would reduce maize yield, which will be declined by 2.9% when the seeding date was delayed by a day. When emergence rate was decreased by 10%, the yield will be dropped by 9.2%. If the height, leaf age and plant dry quality was reduced by 10%, the yield would drop by 13.4%, 11.1% and 5.5%, respectively. The spring drought cut assessment model which can quantitatively assess or forecast the spring drought impact on the yield by emergence date, emergence rate, leaf age and plant dry quality, and the assessment error was about 6.5%, application test also proved that the effect is batter. The relation modes of relative yield and seedling date delayed days, leaf age difference, emergence rate and seedling dry mass were significant, and the physical and biological meaning of such yield evaluation modes were clear with a high statistical reliability. 2a experimental data fitting test and 3a antual application, the errors are within ±6%. This method is simple and objective which can be applied to the real-time quantitative assessment of drought cut through simple's observation and calculation of spring drought, and provides scientific basis for mitigating disaster and developing the business of the drought insurance. ©, 2014, Chinese Society of Agricultural Engineering. All right reserved. Source

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