| Climate change, especially the global warming caused by the excessive emissions of CO2 and other greenhouse gases, has a profound impact on the farmland environment and crops itself, and has a great threat on high and stable yield of grain. Looking for a new agriculture model that can both control and even reduce agricultural carbon emissions and achieve water–saving and high–yield is becoming a problem. The maize is China’s first major crop and important source of food and feed, about 2/3 of which is dry–land maize that often caused serious losses by the drought. The maize need more water and is more sensitive to water stress, the most main factors limiting maize yield is drought which usually cause maize yield decreased by 20% ~ 30%. At the same time, along with climate change in recent years, the summer maize in North China Plain in summer maize growth prophase often suffer from drought stress which threaten the stability of the growth and yield. In view of this, the experiment aimed at summer maize fields, set up different straw conditions and different aswp processing, to explore the inherent physiological mechanism that can achieve maize population synthesis tuning, realize the comprehensive utilization of water, light and heat resources and realize the summer corn output cover patterns combined with the optimization of aswp processing. Discussed by mulching and aswp optimum combination to further improve the utilization efficiency of farmland water and carbon potential, and coordinate farmland ecosystem of water cycle and carbon cycle, finally, we can provide theoretical basis and technical support of water–saving agriculture in the north China plain areas in China.The study was conducted at the Experimental Station of Shandong Agricultural University, which locates in the center of North China Plain, in 2014 and 2015 summer maize growing seasons. The experiment adopted a split plot design arranged in randomized blocks with three replications. Main plots were straw mulching amount: 0, and 0.6 kg m–2; subplots consisted of soil water before sowing: 30 mm, 70 mm, and 110 mm. Each plot was planted for five rows, row spacing was 60 cm, plant distance was 22.2 cm, plant density was 7.5 plants m–2, summer maize variety was “Denghai 661”. At the summer maize 5–leaf stage, straw mulching was carried out by applying winter wheat dry straw that was chopped into 5–8 cm. Soil moisture content, precipitation, farm evapotranspiration, photosynthetic active radiation, dry matter, LAI, soil respiration rate, ears, rows per ear, kernels per row, 1000–grain weight and grain yield were measured to further study the mechanism of water and carbon utilization. The experiment results were as follows:Under the conditition of 70 mm and 110 mm irrigation amount before sowing, the soil water content of straw mulching treatments were significantly higher than nonmulching treatments, but it was opposite for 30 mm. The effect of straw mulching measurement on different levels of soil water content was different. And there was no significant effect of straw mulching on evapotranspiration.The dry matter of every treatment was accumulated gradually in whole growth period in 2 years, and reached the maximum in the mature period. The amount of dry matter accumulation of 2014 was M70 treatment, followed by M110, but there was no significant differents. The amount of dry matter accumulation of 2015 was M110 treatment, followed by M70, and there was no significant different, too. Straw mulching and increasing the soil water before sowing properly have some auxo–action on leaf and ear of summer maize. The biggest ear weight of 2014 and 2015 all occur in M110, which were 1093.8 and 1587.75g·m–2, respectively. The biggest leaf and stem weight was in M70, which was 1502.8g·m–2, but as for 2015, the biggest leaf and stem weight was in M110, which was 948.5g·m–2。As time goes on, summer maize farmland soil respiration rate shows the tendency of decrease and straw mulching has inhibiting effect on summer maize farmland soil respiration rate. There is no consistent effect of aswp on soil respiration rate between different treatments but we can find that with the increase of aswp that the respiratory rate increase in early growing stage, the respiratory rate of 3 aswp condition were consistent, with the increase of aswp that the respiratory rate decrease in late growing stage. There was inhibiting effect of straw mulching on soil surface CO2 flux of summer maize, appropriate aswp helps reduce soil surface CO2 emission flux but not consistent. There was inhibiting effect of straw mulching on respiration/grain, aswp increase is also a way to reduce respiration/grain. The maximum of respiration/grain was in N30 and the minimum of respiration/grain was in M110 in 2 years. The respiration/grain of 2015 was significant lower than 2014, and reduce proportion were 34.4%、40.8%、38.0%、25.3%、15.6% and 6.9%, except N110.The maximum yield was in M110 in 2014 and 2015 summer maize growing seasons, which were 1011.7g·m–2 in 2014 and 1350.69 g·m–2 in 2015. The grain yield of 2015 was significantly higher than 2014. On the one hand, with the increase of awsp, the grain yield increase, on the other hand, straw mulching can help improve the summer maize yield.Straw mulching has the promotion effect of WUE, with the increase of awsp, the WUE increased. In the same condition, the WUE of 2015 was higher than 2014 of summer maize. The max of WUE of 2 years was all in M110, which were 3.2 and 4.6 kg·m–3, respectively. |
PDF Full Text Request