The border effect (BE) is widely observed in crop field experiments, and it has been extensively studied in many crops.  However, only limited attention has been paid to the BE of ratoon rice.  We conducted field experiments on ratoon rice in Qichun County, Hubei Province, Central China in 2018 and 2019 to compare the BE in the main and ratoon crops, and to quantify the contribution of BE in the main crop to that in the ratoon crop.  The BE of two hybrid varieties was measured for the outermost, second outermost, and third outermost rows in each plot of both crops.  To determine the contribution of BE between the two crops, portions of hills in the outermost and second outermost rows were uprooted during the harvest of the main crop so that the second and third outermost rows then became the outermost rows in the ratoon crop.  Overall, the BE on grain yield was greater in the main crop than in the ratoon crop.  In the main crop, the BE on grain yield was 98.3% in the outermost row, which was explained by the BE on panicles m^–2, spikelets/panicle, spikelets m^–2, and total dry weight.  In the ratoon crop, the BE on grain yield was reduced to 60.9 and 27.6% with and without the contribution of the BE in the main crop, respectively.  Consequently, 55.1% of the BE on grain yield in the ratoon crop was contributed from the main crop.  High stubble dry weight and non-structural carbohydrate (NSC) accumulation at the harvest of the main crop were responsible for the contribution of BE in the main crop to that in the ratoon crop.  Our results suggest that increases in stubble dry weight and NSC accumulation at the harvest of the main crop could be important strategies for developing high-yielding cropping practices in the rice ratooning system.

Understanding of how combinations of agronomic options can be used to improve the grain yield and nitrogen use efficiency (NUE) of winter wheat is limited.  A three-year experiment involving four integrated management strategies was conducted from 2013 to 2015 in Tai’an, Shandong Province, China, to evaluate changes in grain yield and NUE.  The integrated management treatments were as follows: current practice (T1); improvement of current practice (T2); high-yield management (T3), which aimed to maximize grain yield regardless of the cost of resource inputs; and integrated soil and crop system management (T4) with a higher seeding rate, delayed sowing date, and optimized nutrient management.  Seeding rates increased by 75 seeds m^–2 with each treatment from T1 (225 seeds m^–2) to T4 (450 seeds m^–2).  The sowing dates were delayed from T1 (5th Oct.) to T2 and T3 (8th Oct.), and to T4 treatment (12th Oct.).  T1, T2, T3, and T4 received 315, 210, 315, and 240 kg N ha^–1, 120, 90, 210 and 120 kg P₂O₅ ha^–1, 30, 75, 90, and 45 kg K₂O ha^–1, respectively.  The ratio of basal application to topdressing for T1, T2, T3, and T4 was 6:4, 5:5, 4:6, and 4:6, respectively, with the N topdressing applied at regreening for T1 and at jointing stage for T2, T3, and T4.  The P fertilizers in all treatments were applied as basal fertilizer.  The K fertilizer for T1 and T2 was applied as basal fertilizer while the ratio of basal application to topdressing (at jointing stage) of K fertilizer for both T3 and T4 was 6:4.  T1, T2, T3, and T4 were irrigated five, four, four and three times, respectively.  Treatment T3 produced the highest grain yield among all treatments over three years and the average yield was 9 277.96 kg ha^–1.  Grain yield averaged across three years with the T4 treatment (8 892.93 kg ha^–1) was 95.85% of that with T3 and was 21.72 and 6.10% higher than that with T1 (7 305.95 kg ha^–1) and T2 (8 381.41 kg ha^–1), respectively.  Treatment T2 produced the highest NUE of all the integrated treatments.  The NUE with T4 was 95.36% of that with T2 and was 51.91 and 25.62% higher than that with T1 and T3, respectively.  The N uptake efficiency (UPE) averaged across three years with T4 was 50.75 and 16.62% higher than that with T1 and T3, respectively.  The N utilization efficiency (UTE) averaged across three years with T4 was 7.74% higher than that with T3.  The increased UPE with T4 compared with T3 could be attributed mostly to the lower available N in T4, while the increased UTE with T4 was mainly due to the highest N harvest index and low grain N concentration, which consequently led to improved NUE.  The net profit for T4 was the highest among four treatments and was 174.94, 22.27, and 28.10% higher than that for T1, T2, and T3, respectively.  Therefore, the T4 treatment should be a recommendable management strategy to obtain high grain yield, high NUE, and high economic benefits in the target region, although further improvements of NUE are required.