Suitable tillage and seeding strategies for wheat can be used to combat excessive residues and poor soil conditions in harvested rice fields. This study investigated the effects of different tillage (zero tillage and rotary tillage) and seeding methods on wheat growth, grain yield, nitrogen (N) uptake and utilization, and economic benefit when the soil moisture was high during the tillage and seeding practices. In 2016–2017, three seeders were tested: SM1-1, SM2, and SM3; in 2017–2018, four seeders were tested: SM1-2, SM2, SM3, and SM4. Although the soil moisture was different between years, zero tillage could be used to reduce the sowing depth, which facilitated early-phase wheat growth and N uptake compared with rotary tillage, resulting in higher grain yield, NUpE, and net return. In 2016–2017 (high wet soil), a small-size seeder (SM1-1) with sowing near the soil surface facilitated higher grain yield, NUpE, and net returns compared with the other seeders; in 2017–2018 (low wet soil), medium-size seeders (SM3 and SM4) were more suitable than small-size seeders (SM1-2 and SM2). In both years, the seeders that performed the best mainly improved the spike numbers while increasing N uptake, especially after anthesis. Zero tillage lowered input costs, but small-size seeders did not reduce costs due to the higher labor costs associated with their low working efficiency. Improving net returns depends largely on increasing yield. In conclusion, zero tillage is recommended for wheat production in harvested rice fields with a high soil moisture content, but the suitable seeding method needs to be confirmed according to the soil moisture content.

In the rice-wheat rotation system, conventional culturing of high yield rice results in poor soil conditions and excessive residues, which negatively affect wheat growth. Tillage and nitrogen (N) use are being sought to address this problem. In order to propose a suitable tillage method and corresponding N management strategy, the influence of three tillage methods (i.e., plow tillage followed by rotary tillage (PR), rotary tillage twice (RR), and no-tillage (NT)) and nine forms of N management strategies (i.e., three total N rates × three N-splitting schemes) were investigated in a field experiment from 2016 to 2017 (2017) and 2017 to 2018 (2018), using grain yield, grain protein content (GPC), N uptake efficiency (NUpE), and net returns as evaluation indexes. Grain yield, GPC, and net returns were lower in 2017 than 2018, likely as a result of weak seedling growth caused by high soil moisture before and after seeding. In 2017, NT achieved higher grain yield, NUpE, and net returns compared to PR or RR, while grain yield and net returns were higher under tillage in 2018, especially PR. Increased total N rates (210–270 kg ha−1) promoted all evaluation indexes, but suitable timing and corresponding rates of N application are dependent on the environment. These results indicate that the combination of NT and applying N at lower rates and only a few times (i.e., 168 and 72 kg ha−1 applied at pre-sowing and when flag leaves are visible) when the soil is not suitable for tillage is the best method for cutting costs and improving benefits. Under suitable conditions for tillage, PR and intensive management strategies (i.e., 135, 27, 54, and 54 kg ha−1 applied at pre-sowing, four-leaf, jointing, and booting, respectively) could be adopted to increase overall yield, quality, and benefits.

Optimizing soil properties to match ecological conditions can alleviate stress damage and promote crop growth. However, the suitable soil conditions for wheat growth in an integrated rice–wheat breeding scheme under high rainfall and the mechanisms that affect yield production are not well known. Field experiments were carried out at two sites, which were all located in Jiangsu Province, China, a subtropical monsoon climate zone during two wheat growing seasons, to assess the effects of plow tillage followed by rotary tillage (PR) and no-tillage (NT) on soil physical and chemical properties, wheat seedling growth, grain yield, and spike amounts and quality. The finding indicates that with the reduction in soil mixing, soil bulk density was higher in NT than in PR, which helped to maintain moisture in dry soil. In soils with high water content, in NT, when the wheat field was subjected to waterlogging stress, the drainage decreased to deeper soil possibly due to reduced infiltration and a higher evaporation of surface water. The diurnal variation in soil temperature decreased in NT, and when the soil was cold, NT helped to insulate soils at 0–25 cm. Compared with PR, the contents of available nitrogen and phosphorus increased at 0–20 cm in NT. Root biomass and root activity of wheat seedlings at 0–20 cm were also greater in NT than in PR. Compared with PR, wheat also had more culms at the beginning of the overwintering stage, more spikes, and higher grain yield in NT, but the differences were not significant under excessive soil moisture. Therefore, the soil hydrothermal environment and spatial distributions of nutrients in NT promoted shallow root growth and tiller development in the early phase of wheat growth, which led to higher amounts of spikes per plant that resulted in high-yielding wheat crops.