Cultivar and sowing date selection are major factors in determining the yield potential of any crop and in any region. To explore how climate change affects these choices, this study performed a regional scale analysis using the well-validated APSIM-maize model for the Northeast China Plain (NEC) which is the leading maize (Zea mays L.) producing area in China. Results indicated that high temperature had a significantly negative effect on grain yield, while effective accumulated temperature and solar radiation had significant positive effects on grain yield and kernel number. Cloudy and rainy weather in flowering stage had significant negative effects on kernel number. Delayed sowing led to less cloudy and rainy weather during flowering and reduced the negative effect on kernel number. Higher diurnal thermal range and less precipitation during the grain-filling stage also increased the 1000-kernel weight. Delayed sowing, however, also significantly increased the risk of early senescence and frost (>80%) in middle and high latitude areas. In the middle and high latitude areas of the NEC, the grain yield of a long-season cultivar (LS) under early sowing (I) (6.2–19.9%) was significantly higher than under medium sowing (II) or late sowing (III), and higher than that of an early sown (I) short-season (SS) and medium-season cultivar (MS). In the low latitude area of the NEC, the grain yield of MS under medium sowing date (II) was higher than that under I and III, meanwhile, this was also higher than that of SS and LS. Therefore, under climate warming, LS sown earlier in high and medium latitudes and MS sown medium in low latitude were the appropriate cultivar and sowing date choices, which could mitigate the stress of high temperatures and reduce the risk of early senescence and frost. Cultivar and sowing date selection are effective measures to alleviate negative effects of climate change on maize production in the NEC, and provides valuable advice for breeders on cultivar selection, and the choice of varieties and sowing dates for farmers in actual production.

Tillage practices can change the soil environment (including soil properties and enzyme activity) and the rhizosphere microbial community, thereby inducing changes in root growth and the nutrient uptake capacity. This study was carried out on a long-term (since 1983) tillage field experimental platform. It aimed to explore the effects of tillage practices and growth stages on maize root development, soil properties, and the rhizosphere microbial community. The results can provide a theoretical basis for the further analysis of crop–soil–microbial interactions. In our study, we investigated the abundance and diversity of the rhizosphere microbial community and their relationship with root growth characteristics and soil factors under long-term (since 1983) conventional tillage (CT), subsoil tillage (ST), and no-tillage (NT) practices using quantitative PCR and high-throughput 16S/ITS sequencing. In 2020, at the 30-days-after-silking (VT 30) stage, NT increased the root length, root dry weight, N accumulation, and N uptake rate of maize roots compared with CT by 16.7%, 16.3%, 41.9%, and 41.9%, respectively. In 2020, at the 12th leaf (V12) and VT 30 stages of maize, NT significantly increased the contents of soil total nitrogen (by 16.3% and 11.0%, respectively), total carbon (by 23.9% and 12.9%, respectively), soil organic matter (by 24.8% and 10.3%, respectively), and soil urease activity (by 5.5% and 5.6%, respectively) compared with CT. Moreover, NT significantly increased the bacterial and fungal abundances compared with CT. Redundancy analysis (RDA) showed that the variation in the microbial structure correlated markedly with the alteration in root indicators, soil properties, and enzyme activities. Long-term no-tillage improved the abundance and diversity of rhizosphere microbial communities by increasing the soil total nitrogen, total carbon, and soil organic matter, and promoted the N accumulation of roots and their uptake rate.