[Simulation of the responses of spring wheat yield to the rates and depths of nitrogen application in dryland based on APSIM model]. / 基于APSIM模型的旱地春小麦产量对施氮量和施氮深度的响应模拟.

Nitrogen limitation is an important factor for the improvement of crop water production potential in rain-fed areas of the Loess Plateau. The reasonable deep application of nitrogen fertilizer is a promising method to increase yield of rain-fed crop. Based on APSIM model, this study simulated spring wheat yield under different nitrogen application rates and depths, by using meteorological observation data from 1990 to 2020 in the semiarid areas of central Gansu Province, aiming to provide theoretical reference for optimizing wheat fertilization strategy. The results showed that the determination coefficient of simulated spring wheat yield, biomass and soil water content in 0-200 cm soil profile was greater than 0.80, the normalized root mean square error was less than 0.2, and the model validity index was greater than 0.5. These results indicated that the model had good fitting and adaptability in the test area. Across all the levels within the experimental design, increasing nitrogen application rates could significantly increase the yield of spring wheat in different precipitation years, and increasing nitrogen application depth could significantly increase spring wheat yield in wet and normal years, but had no effect in dry years. The rate and depth of nitrogen application had significant interaction effects on spring wheat yield in wet and normal years, but not in dry years. According to the binary quadratic regression fitting equation, when the potential maximum yield reached 2749 kg·hm-2 in wet year, nitrogen application depth was 22.7 cm, and nitrogen application rate was 245 kg·hm-2. When the maximum potential yield reached 2596 kg·hm-2 in normal year, nitrogen application depth was 20.6 cm, and nitrogen application rate was 235 kg·hm-2. Integrating the effects of nitrogen application rate and depth on yield, biomass and agronomic efficiency of nitrogen fertilizer, and farmer's fertilizer application habits, the recommended nitrogen application depth was 20-23 cm, and nitrogen application amount was 120-150 kg·hm-2, which could further improve water productivity and nitrogen use efficiency of spring wheat in arid areas of central Gansu Province.

[Effects of vertical rotary subsoiling with combined organic and inorganic fertilization on water use efficiency and yield of forage maize in a semi-arid area.] / åŠå¹²æ—±åŒºç«‹å¼æ·±æ—‹è€•å’Œæœ‰æœºæ— æœºè‚¥é æ–½å¯¹é¥²ç”¨çŽ‰ç±³æ°´åˆ†åˆ©ç”¨æ•ˆçŽ‡å’Œäº§é‡çš„å½±å“.

Both reasonable soil tillage and fertilization management play critical roles in improving the yield and water use efficiency (WUE) of forage maize in the semi-arid area of Loess Plateau. A field experiment was conducted at Dingxi experimental station of Gansu Academy of Agricultural Sciences between 2017 and 2019. We explored the effects of tillage method and fertilization type on yields and WUE of forage maize, as well as the economic benefits. There were four treatments in the experiment, including traditional rotary tillage + organic-inorganic fertilization (TOF), deep rotary tillage + organic-inorganic fertilization (DOF), and vertical rotary subsoiling + organic-inorganic fertilization (VROF), and the traditional rotary tillage + inorganic fertilization as the control (TF). Our results showed that, compared with DOF, TOF, TF, and VROF all decreased soil water storage in 0-300 cm soil layer at flowering stage, ranging from 16.9 mm to 79.9 mm, but they all increased soil water consumption by 9.7-22.4 mm during vegetative growing stages, 11.0-19.8 mm during reproductive stage in the dry years. Due to significant improvement in water absorption, VROF increased dry matter weight at maturity by 3.9%-13.4% compared to other treatments. Similarly, plant height, ear length, grain number per ear, 100-grain weight, and double ear rate under VROF were significantly increased, while bald head length was decreased significantly, when compared with other treatments. As a result, over the three experimental seasons, VROF increased the grain and biological yield by 4.3%-51.5% and 4.3%-25.7% compared to other treatments, respectively. Accordingly, WUE calculated by grain and biomass yields were increased by 2.7%-36.9% and 3.6%-13.5% under VROF, compared to other treatments. VROF increased the unit gross total output value and the net income by 5.1%-32.9% and 6.9%-80.5% respectively, compared to other treatments. These results demonstrated that VROF is a drought-resistant and yield-increasing farming technology for sustainable forage maize production in the semi-arid area of the Loess Plateau, Northwest China.

[Effects of micro-ridge-furrow with plastic mulching and bunching seeding on soil hydrothermal environment and its response to photosynthesis and grain yield of spring wheat]. / å ¨è†œå¾®åž„æ²Ÿç©´æ’­å¯¹æ˜¥å°éº¦åœŸå£¤æ°´çƒ­çŽ¯å¢ƒçš„å½±å“åŠå ¶å ‰åˆå’Œäº§é‡æ•ˆåº”.

The relieving of drought and cold restriction on spring wheat development is one of the key factors increasing wheat yield in arid areas of central Gansu Province. A field experiment with spring wheat (Longchun No. 35) was carried out in central Gansu Province from 2016 to 2018. There were three treatments: 1) micro-ridge-furrow with whole field plastic mulching and bunching seeding (PRF), 2) whole field soil plastic mulching and bunching seeding (PMS), 3) bunching seeding without mulching (CK). We measured soil temperature in 0-25 cm profile, soil water content in 0-300 cm profile, leaf SPAD, photosynthetic rate, transpiration rate, aboveground biomass in different growth stages, and grain yield to understand the effect of PRF on soil hydrothermal environment, spring wheat yield and water use efficiency (WUE) from the aspect of soil hydrothermal, canopy development and grain yield. The results showed that mean soil temperature in 0-25 cm profile of PRF and PMS increased by 2.8 ℃ and 2.5 ℃ at the seedling stage, decreased by 1.4 ℃ and 0.9 ℃ from filling to maturity stage, respectively. Soil water storage in 0-300 cm profile of PRF and PMS increased by 59.7 mm and 41.8 mm from sowing to seedling stage. Water consumption of PRF and PMS increased by 46.1 mm and 39.8 mm from seedling to filling stage. PRF increased average soil temperature in 0-25 cm profile by 0.3 ℃ at seedling stage, but decreased by 0.5 ℃ from filling to maturity stage, and increased soil water storage in 0-300 cm profile by 18.0 mm from sowing to seedling stage. PMF increased water consumption by 13.0 mm from booting to maturing stage, as compared with PMS. Based on the optimizated soil hydrothermal conditions, leaf SPAD value, aboveground biomass, net photosynthetic rate, and transpiration rate of PRF increased, as compared with PMS and CK. The PRF increased grain yield by 9.1% and 36.5%, WUE by 5.9% and 30.8% compared to PMS and CK, respectively. Consequently, PRF increased soil temperature at wheat seedling stage, reduced it from filling to maturing stage, improved wheat water consumption from sowing to filling stage, increased leaf SPAD value and aboveground biomass, promoted photosynthetic function in leaf from seedling to filling stage, and consequently led to increased yield and water utilization. Such effects were more significant in dry year (2016 and 2017).

[Effects of organic fertilizer application on flag leaf C/N ratio, photosynthetic characteristics and yield of spring wheat with full plastic film mulching]. / å ¨è†œè¦†åœŸä¸‹æ–½æœ‰æœºè‚¥å¯¹æ˜¥å°éº¦æ——å¶ç¢³æ°®æ¯”ã€å ‰åˆç‰¹æ€§å’Œäº§é‡çš„å½±å“.

A field experiment was conducted in the rain-fed semi-arid region of central Gansu in 2016 and 2017, with the treatments 1) hill-drop flat planting with full plastic film mulching (PMS), 2) hill-drop flat planting with full plastic film mulching plus organic fertilizers (PMO), and 3) hill-drop flat planting without soil mulching (CK). We investigated the relations among soil moisture, photosynthetic rate (Pn), stomatal conductance (gs) and transpiration rate (Tr), C/N ratio, and total nitrogen of flag leaf from the heading stage to the seed-filling stage in different treatments to probe into their effects on the yield and yield components of spring wheat variety 'Longchun 27'. The results showed that organic fertilizer application could increase soil moisture at the middle and late growth stages of spring wheat. PMO increased soil water storage in 0-300 cm depth from the heading stage to the seed filling stage by 4.6% and 8.5%, decreased population canopy temperature by 0.1-1.3 ℃ and 1.4-4.9 ℃, increased net photosynthetic rate of flag leaf by 9.3% and 29.7%, stomatal conductance by 30.9% and 103.8%, transpiration rate by 5.1% and 55.0%, total nitrogen content by 6.6% and 18.9%, and decreased C/N ratio by 6.4% and 22.8%, respectively. Compared with PMS and CK, PMO significantly improved grain number per spike and 1000-grain weight, and increased grain yield by 9.1% and 53.7%, respectively. From the heading stage to filling stage, the Pn and gs of flag leaf had negative correlation with C/N, while C/N was negatively correlated with grain yield. Consequently, PMO could improve soil water storage and promote photosynthesis of flag leaf, reduce the intensity of physiological drought stress and the limitations of nitrogen absorption and assimilation in flag leaf from the heading stage to the seed-filling stage, and increase grain number and grain weight and consequently the yield of spring wheat in semi-arid region.

Regulation of mulch conditions on photosynthesis and water utilization of spring wheat in northwest semi-arid area of China.

A field experiment was conducted from 2015 to 2016 in the northwestern Loess Plateau, China, to analyze the relationships among flag-leaf photosynthetic characteristics, water-consumption characteristics, and yield components of spring wheat (Triticum aestivum 'Longchun 35'). There were three treatments: whole-field plastic mulching (PMS), sand mulching (SM), and uncovered (CK). The results showed that soil-water storage levels at 0-300 cm of soil profile before wheat filling under PMS and SM treatments were greater than that in CK by 47.8 and 31.6 mm, respectively, while that under PMS was lower than CK by 15.6 mm at the filling stage. Water consumption under PMS and SM increased in the flagging-heading and flowering-filling stages compared with the CK. Leaf area indices under PMS and SM were increased by 59.0%-73.7% and 40.1%-52.7%, respectively, and leaf SPAD values were increased by 3.5%-28.4% and 2.9%-23.9%, respectively, compared with CK. The net photosynthetic rate of PMS was increased by 23.5%, 33.0% and 17.7% at the flagging, heading, and flowering stages. The corresponding stoma-tal conductance rate was increased by 32.6%, 76.4% and 66.9%, respectively. Net photosynthetic and stomatal conductance rates at the filling stage were decreased by 26.2% and 16.4%, respectively. At the heading, flowering, and filling stages, stomatal limitation values in PMS were decreased by 14.6%, 23.9% and 22.3%, respectively, and by 25.7%, 29.8% and 17.4%, respectively in SM. The instantaneous water-use efficiency of spring wheat in PMS was increased by 57.8% at the flagging stage and decreased by 11.2% at the flowering stage. At the heading and flowering stages, the apparent quantum efficiency was increased by 22.6% and 18.7% in PMS, and by 26.8% and 14.3% in SM, respectively. Plant height and yield component indices in PMS and SM were significantly greater than that in CK, with the enhancement being greater than that in dry years. Grain yield was increased by 36.2% and 8.7% and water-use efficiency increased by 9.4% and 3.4% in PMS and SM, respectively. PMS and SM treatments increased soil water storage before the pre-filling stage of wheat, aggravated water consumption during the flagging-shooting and flowering-filling stages, resulting in greater SPAD values and leaf area indices, which promoted the photosynthetic functions of flag leaves, facilitated sink formation and photosynthetic assimilate transportation, resulting in increased grain yields and water use efficiency of spring wheat. The effects of PMS treatment were more remarkable than those of SM in terms of increasing spring wheat's yield potential in wet years and adaptability in dry years.

Differences in Major Bleeding Events Between Patients With Severe Hemophilia A and Hemophilia B: A Nationwide, Population-Based Cohort Study.

There has been an ongoing debate as to whether hemophilia A (HA) is more severe than hemophilia B (HB), and there are studies supporting each side of the argument. The study aimed to investigate whether any differences in major bleeding events exist between patients with severe HA and HB. A nationwide, population-based retrospective cohort study using the National Health Insurance Research Database was conducted. We compared 658 patients with severe HA and 137 patients with severe HB without inhibitors from 1997 to 2013, during the period when adult patients older than 18 years old were treated with the on-demand therapy since birth. There was no significant difference between patients with severe HA and HB in the rate of major bleeding events, with an adjusted relative ratio of 0.79 (95% confidence interval [CI]: 0.36-1.71, P = .548). There was also no significant difference in the incidence rate of major bleeding events between adult patients with HA and HB with the on-demand therapy, and an adjusted hazard ratio (HR) of 0.82 (95% CI: 0.65-1.02). However, patients with HA had a lower incidence rate of intracranial hemorrhage, with an adjusted HR of 0.44 (95% CI: 0.25-0.79). In addition, no significant difference in the frequency of major bleeding events requiring hospitalization between patients with HA and HB was found, P > .05. In conclusion, the study demonstrated that patients with severe HB encountered a similar rate of major bleeding events to those with severe HA.