Effects of nitrogen management on the ratoon crop yield and head rice yield in South USA

Ratoon rice cropping is an important component of the rice cropping system in Texas and south Louisiana, USA, and expanded to Asian countries in 1970. Two field studies were conducted with widely planted rice(Oryza sativa L.) cultivars at Eagle Lake, Texas, USA to determine the effects of nitrogen(N) management in main(first) crop(MC) and ratoon(second) crop(RC) on RC yield. In 2012 and 2013, one cultivar(Presidio) was adopted to determine the effects of RC N management on ratoon yield and head rice yield. In 2016 and 2017, CL153, CL163 and CL272 in addition to Presidio were adopted to examine the effect of MC N management on ratoon yield and head rice yield. N applied at preflood after MC harvest considerably improved RC yield. Application of 99 kg N ha–1 at preflood after MC harvest was practically adequate for RC regrowth, development and approaching the yield potential for Presidio. RC could produce quite high average grain yields of 5.90 to 6.53 t ha–1 in 2012 and 2013, respectively. Main crop N rate only significantly affected MC yield; however, given N applied of 99 kg ha–1 at preflood after MC harvest, ratoon yield was not significantly affected by MC N rate. Neither the main nor ratoon crop N management had a significant effect on RC head rice yield. Considerable RC head rice yields(55–65%) were observed in all of the four cultivars and 4 years except for CL272 in 2016. These results indicat that without very high N fertilizer application, rice ratoon crop could produce a considerable grain yield and an expectative head rice yield. Rice ratooning could be a practical way to increase rice yields with the minimal input in south Texas and regions with a similar climate.     

Growth and nitrogen productivity of drip-irrigated winter wheat under different nitrogen fertigation strategies in the North China Plain

Excessive application of nitrogen (N) fertilizer is the main cause of N loss and poor use efficiency in winter wheat (Triticum aestivum L.) production in the North China Plain (NCP).  Drip fertigation is considered to be an effective method for improving N use efficiency and reducing losses, while the performance of drip fertigation in winter wheat is limited by poor N scheduling.  A two-year field experiment was conducted to evaluate the growth, development and yield of drip-fertigated winter wheat under different split urea (46% N, 240 kg ha^–1) applications.  The six treatments consisted of five fertigation N application scheduling programs and one slow-release fertilizer (SRF) application.  The five N scheduling treatments were N0–100 (0% at sowing and 100% at jointing/booting), N25–75 (25% at sowing and 75% at jointing and booting), N50–50 (50% at sowing and 50% at jointing/booting), N75–25 (75% at sowing and 25 at jointing/booting), and N100–0 (100% at sowing and 0% at jointing/booting).  The SRF (43% N, 240 kg ha^–1) was only used as fertilizer at sowing.  Split N application significantly (P<0.05) affected wheat grain yield, yield components, aboveground biomass (ABM), water use efficiency (WUE) and nitrogen partial factor productivity (NPFP).  The N50–50 and SRF treatments respectively had the highest yield (8.84 and 8.85 t ha^–1), ABM (20.67 and 20.83 t ha^–1), WUE (2.28 and 2.17 kg m^–3) and NPFP (36.82 and 36.88 kg kg^–1).  This work provided substantial evidence that urea-N applied in equal splits between basal and topdressing doses compete economically with the highly expensive SRF for fertilization of winter wheat crops.  Although the single-dose SRF could reduce labor costs involved with the traditional method of manual spreading, the drip fertigation system used in this study with the N50–50 treatment provides an option for farmers to maintain wheat production in the NCP.     

Grain yield,nitrogen use efficiency and physiological performance of indica/japonica hybrid rice in response to various nitrogen rates

Utilizing the heterosis of indica/japonica hybrid rice (IJHR) is an effective way to further increase rice grain yield.Rational application of nitrogen (N) fertilizer plays a very important role in using the heterosis of IJHR to achieve its great yield potential.However,the responses of the grain yield and N utilization of IJHR to N application rates and the underlying physiological mechanism remain elusive.The purpose of this study was to clarify these issues.Three rice cultivars currently used...     

Plastic-film-side seeding,as an alternative to traditional film mulching,improves yield stability and income in maize production in semi-arid regions

Planting under plastic-film mulches is widely used in spring maize production in arid-cold regions for water conservation and warming the soil.To ameliorate the associated issues such as plastic-film residues and additional labor during the“seedling release” in spring maize production, we have developed a plastic-film-side seeding (PSS) technology with the supporting machinery.In the semi-arid regions of Northwest China, a 7-year trial demonstrated that PSS increased plant number per hectare by ...     

Substituting nitrogen and phosphorus fertilizer with optimal amount of crop straw improves rice grain yield,nutrient use efficiency and soil carbon sequestration

Crop straw return after harvest is considered an important way to achieve both agronomic and environmental benefits.  However, the appropriate amount of straw to substitute for fertilizer remains unclear.  A field experiment was performed from 2016 to 2018 to explore the effect of different amounts of straw to substitute for fertilizer on soil properties, soil organic carbon (SOC) storage, grain yield, yield components, nitrogen (N) use efficiency, phosphorus (P) use efficiency, N surplus, and P surplus after rice harvesting.  Relative to mineral fertilization alone, straw substitution at 5 t ha^–1 improved the number of spikelets per panicle, effective panicle, seed setting rate, 1 000-grain weight, and grain yield, and also increased the aboveground N and P uptake in rice.  Straw substitution exceeding 2.5 t ha^–1 increased the soil available N, P, and K concentrations as compared with mineral fertilization, and different amounts of straw substitution improved SOC storage compared with mineral fertilization.  Furthermore, straw substitution at 5 t ha^–1 decreased the N surplus and P surplus by up to 68.3 and 28.9%, respectively, compared to mineral fertilization.  Rice aboveground N and P uptake and soil properties together contributed 19.3% to the variation in rice grain yield and yield components.  Straw substitution at 5 t ha^–1, an optimal fertilization regime, improved soil properties, SOC storage, grain yield, yield components, N use efficiency (NUE), and P use efficiency (PUE) while simultaneously decreasing the risk of environmental contamination.     

Millet/peanut intercropping at a moderate N rate increases crop productivity and N use efficiency,as well as economic benefits,under rain-fed conditions

Cereal and legume intercropping has been widely adopted to increase crop productivity in sustainable farming systems worldwide.  Among different intercropping combinations, millet and peanut intercropping can be adapted to most water-limited areas.  However, there are few studies on the differences in yield characteristics and nitrogen use efficiency between millet/peanut intercropping and monocultures under different nitrogen (N) application rates.  The objective of this study was to determine the yield advantages and economic benefits, as well as the appropriate N application rate, of millet/peanut intercropping.  A two-year field experiment was conducted with three cropping patterns (monoculture millet, monoculture peanut and millet/peanut intercropping) and four N rates (0, 75, 150 and 225 kg ha⁻¹).  The results showed that the land equivalent ratio (LER) and net effect (NE) of the intercropping system reached their highest levels at the N input of 150 kg ha⁻¹ in 2018 and 2019 (1.04 for LER, 0.347 Mg ha⁻¹ for NE, averaged across two years).  Millet was the dominant crop in the intercropping system (aggressivity of millet and peanut (Amp)>0, competitive ratio of millet and peanut (CRmp)>1), and millet yields achieved their highest values at N inputs of 225 kg ha⁻¹ for monoculture and 150 kg ha⁻¹ for intercropping.  NUE reached its highest levels with N inputs of 150 kg ha⁻¹ for all planting patterns over the two years.  Intercropping combined with an N input of 150 kg ha⁻¹ achieved the highest net income of 2 791 USD ha⁻¹, with a benefit-cost ratio of 1.56, averaged over the two years.  From the perspective of economics and agricultural sustainable development, millet/peanut intercropping at 150 kg N ha⁻¹ seems to be a promising alternative to millet or peanut monoculture.     

The Nutrient Expert decision support system improves nutrient use efficiency and environmental performance of radish in North China

Excessive fertilization has led to nutrient use inefficiency and serious environmental consequences for radish cultivation in North China.The Nutrient Expert(NE) system is a science-based,site-specific fertilization decision support system,but the updated NE system for radish has rarely been evaluated.This study aims to validate the feasibility of NE for radish fertilization management from agronomic,economic,and environmental perspectives.A total of 46 field experiments were conducted over four...     

施氮量及打顶方式对棉花营养积累与分配及产量的影响

以‘新陆早57号’棉花品种为试验材料,研究了不同施氮量（0、100、200、300、400 kg·hm^-2）对化学封顶与人工打顶下棉花营养积累与分配等的影响。结果表明：在施氮量达到300 kg·hm^-2后,化学封顶棉花地上部分干物质积累量和氮素积累量仍有小幅增长,而人工打顶棉花呈现下降趋势。棉花干物质快速积累期化学封顶处理为出苗后59~109 d,而人工打顶为出苗后56~100 d。在棉花生育后期（打顶后30~60 d）,同等施氮量条件下化学封顶棉花地上部分干物质积累量及氮素积累量高于人工打顶棉花。该研究最佳施氮量为300 kg·hm^-2时,可显著增加棉花单株结铃数0.66~1.66个,平均增产26.72%。     

Sustainability of the rice–crayfish farming model in waterlogged land: A case study in Qianjiang County,Hubei Province,China

The rice–crayfish farming model has been rapidly developed and become an economically viable method to supply food in China in recent years.  However, its environmental and economic sustainability has not been thoroughly investigated.  This study uses a survey in 2016 and a field experiment in 2017 in Qianjiang, Hubei Province, China to assess the relative economics of concurrent rice–wheat (RW), rice–crayfish (RC), and crayfish monoculture (CM) models in waterlogged land areas.  The field survey indicated that the RC model had a higher benefit–cost ratio (3.5:1) than the RW (2.0:1) and CM (3.1:1) models and the RC model protected farmers’ enthusiasm for grain production facing unfavourable weather conditions.  The field experiment aimed to explore nitrogen management strategies in RC fields.  In the experiment, four levels of nitrogen concentration gradient - 0 kg N ha^–1 (0 N), 75 kg N ha^–1 (75 N), 150 kg N ha^–1 (150 N) and 225 kg N ha^–1 (225 N), were set in a 2-year-old rice–crayfish (RC2) field, an 8-year-old rice–crayfish (RC8) field, and a RW field as a control.  The field experiment results suggested that the peak  rice yield in RW, RC2, and RC8 occurred when 225 N, 150 N and 75 N were used, respectively.  In RC2 and RC8, however, residual feed-nitrogen that was not used by crayfish was utilized by rice plants.  Thus, an optimal amount of nitrogen in RC fields was proposed to improve the nitrogen use efficiency and reduce environmental pollution by nitrogen fertilizer.  Farmers use less nitrogen but have higher net income in RC than in RW and CM.  It is necessary to sustainably develop integrated farming technologies (i.e., proper field configurations for rice fields) to effectively sustain rice production.  The results also showed that the RC farming model was a viable diversification option for rice farmers in waterlogged land.       

化学打顶后使用外源物质对棉花脱叶催熟及产量品质的影响

为了探究化学打顶条件下，不同外源物质对棉花脱叶催熟和产量品质的影响，以新陆早67 号为材料，于2019 年在新疆呼图壁县大丰镇进行田间试验，采用裂区区组试验设计，于化学打顶后叶面喷施3种剂量的4种外源物质：缩节胺（75、150和225 g·hm^-2）、烯效唑（150、300和450 g·hm^-2）、芸苔素（0.375、0.75和1.125 g·hm^-2）和赤霉素（150、300和450 g·hm^-2），以清水为CK处理，调查不同处理棉花的脱叶率、吐絮率及产量和品质性状。结果表明，在化学打顶基础上喷施不同外源物质均对棉花的脱叶吐絮有增效作用，脱叶率和吐絮率分别较CK提高了5.05%~17.59%和11.61%~32.87%，对挂枝率的影响不显著。中剂量芸苔素处理（0.75 g·hm^-2）的脱叶效果最好，脱叶率达到95.33%；低剂量芸苔素处理（0.375 g·hm^-2）的催熟效果最佳，吐絮率达到98.11%。各处理对棉花产量及品质均有显著影响，中剂量芸苔素处理（0.75 g·hm^-2）的籽棉产量最高，较CK显著提高了19.27%；中剂量赤霉素处理（300 g·hm^-2）的棉花在纤维品质方面表现最佳。中、低剂量的芸苔素处理（0.375~0.75 g·hm^-2）和中、低剂量的赤霉素处理（150~300 g·hm^-2）可以对化学打顶后棉花的脱叶催熟起到增效作用，有效提高棉花籽棉产量，对棉花纤维品质的优化效果较好。     

Optimization of slow-release fertilizer application improves lotus rhizome quality by affecting the physicochemical properties of starch

To achieve the dual goals of high yield and good quality with low environmental costs,slow-release fertilizer (SRF) has been widely used in lotus cultivation as new type of fertilizer instead of traditional nitrogen fertilizer.However,the optimal amount of SRF and how it would promote lotus rhizome quality remain unclear.This study was designed to investigate the photosynthetic characteristics and the synthesis,accumulation,and physicochemical properties of lotus rhizome starches under six SRF l...     

dep1 improves rice grain yield and nitrogen use efficiency simultaneously by enhancing nitrogen and dry matter translocation

The rice cultivars carrying dep1(dense and erect panicle 1) have the potential to achieve both high grain yield and high nitrogen use efficiency(NUE). However, few studies have focused on the agronomic and physiological performance of those cultivars associated with high yield and high NUE under field conditions. Therefore, we evaluated the yield performance and NUE of two near-isogenic lines(NILs) carrying DEP1(NIL-DEP1) and dep1-1(NIL-dep1) genes under the Nanjing 6 background at 0 and 120 kg ...     

Nitrogen management improves lodging resistance and production in maize (Zea mays L.) at a high plant density

Lodging in maize leads to yield losses worldwide. In this study, we determined the effects of traditional and optimized nitrogen management strategies on culm morphological characteristics, culm mechanical strength, lignin content,root growth, lodging percentage and production in maize at a high plant density. We compared a traditional nitrogen(N) application rate of 300 kg ha–1(R) and an optimized N application rate of 225 kg ha^–1(O) under four N application modes: 50% of N applied a...     

化学封顶剂不同浓度对棉花农艺性状及产量、品质的影响

【目的】研究化学封顶剂不同浓度的增效缩节胺对棉花不同品种的封顶效果,为新疆棉花化学封顶技术的应用提供理论依据。【方法】以新陆早61号、新陆早67号、新陆早72号为材料,不打顶和人工打顶为对照,设置低浓度(缩节胺90 g/hm²+助剂60 ml/hm²)、中浓度(180 g/hm²+120 ml/hm²)、高浓度(270 g/hm²+180 ml/hm²)3个处理,研究喷施不同浓度化学封顶剂对棉花农艺性状及产量、品质的影响。【结果】与不打顶相比,化学封顶有效控制棉株农艺性状;与人工打顶处理相比,高浓度处理(270 g/hm²+180 ml/hm²)下株高增加了3.0~8.7 cm、果枝数增加了0.8~1.93 台、株宽降低1.4%~3.4 %、主茎节间数增加了0.7~1.2 节。与人工打顶处理相比,产量构成因子各浓度处理下无显著差异。【结论】使用高浓度增效缩节胺封顶具有更好的封顶效应。增效缩节胺化学封顶剂的使用,可以有效替代人工打顶,且产量、品质不降低。     

Grain yield and nitrogen use efficiency of an ultrashort-duration variety grown under different nitrogen and seeding rates in direct-seeded and double-season rice in Central China

Nitrogen(N) and seeding rates are important factors affecting grain yield and N use efficiency(NUE) in directseeded rice. However, these factors have not been adequately investigated on direct-seeded and double-season rice(DDR) in Central China. The objective of this study was to evaluate the effects of various N and seeding rates on the grain yield and NUE of an ultrashort-duration variety grown under DDR. Field experiments were conducted in 2018 in Wuxue County and 2019 in Qichun County, Hubei...     

黄淮海区主推夏播玉米品种籽粒脱水特性研究

[目的]籽粒机收是现代玉米生产发展的趋势和方向.生理成熟期籽粒含水率及生理成熟后籽粒物理脱水速率是决定玉米能否机收籽粒的关键因素,明确不同玉米品种籽粒脱水特性差异及其影响因素,可为机收籽粒玉米品种选育和推广提供理论依据.[方法]2017—2018年,以京农科728等18个黄淮海区主推夏播玉米品种为研究材料,测定籽粒含水...     

Increasing the appropriate seedling density for higher yield in dry direct-seeded rice sown by a multifunctional seeder after wheat-straw return

Dry direct-seeded rice(DDR) sown using a multifunctional seeder that performs synchronous rotary tillage and sowing has received increased attention because it is highly efficient, relatively cheap, and environmentally friendly. However,this method of rice production may produce lower yields in a rice–wheat rotation system because of its poor seedling establishment. To address this problem, we performed field experiments to determine the rice yield at five seedling density levels(B1, B2, B3, B4,...     

An economic and viable approach to improve wheat quality in Qinghai–Tibetan Plateau,China

Wheat flour products are the main dietary component of the Qinghai–Tibetan Plateau(QTP) population in China.However, the high altitude restricts the local wheat quality and quantity, and the applied nitrogen rate is higher than the optimal rate for wheat planting. In this study, we considered whether reducing the amount of nitrogen fertilizer and introducing the superior varieties from the North China Plain(NCP) are viable ways to increase the wheat quality and quantity in the QTP. Three and fou...     

Deciphering the morpho–physiological traits for high yield potential in nitrogen efficient varieties(NEVs):A japonica rice case study

The use of nitrogen(N)-efficient rice(Oryza sativa L.) varieties could reduce excessive N input without sacrificing yields. However, the plant traits associated with N-efficient rice varieties have not been fully defined or comprehensively explored. Here, three japonica N-efficient varieties(NEVs) and three japonica N-inefficient varieties(NIVs) of rice were grown in a paddy field under N omission(0 N, 0 kg N ha-1) and normal N(NN, 180 or 200 kg N ha-1) treatments. Results showed that NEVs exhib...     

化学封顶剂不同浓度处理对棉花农艺及产量性状的影响

[目的]研究新疆南疆棉区缩节胺(1,1-dimethyl-piperidinium chloride,DPC)化学封顶对棉花主要农艺性状及产量性状的影响,为新疆南疆棉花化学封顶技术提供理论支撑.[方法]于2019年在新疆南疆阿拉尔市16团开展田间试验,以人工打顶为对照,采用完全随机设计,研究不同DPC用量(0、90、1...