Root characteristics and yield of rice as affected by the cultivation pattern of strong seedlings with increased planting density and reduced nitrogen application

To address the relationships between the amount of nitrogen fertilizer application and the yield of double cropping rice systems,we investigated the effects of a cultivation pattern of strong seedlings with increased planting density and reduced nitrogen application(SDN)on the morphological and physiological characteristics of double cropping rice.Our results indicated that the effects of SDN on the morphological characteristics of the single plant roots of double cropping rice were not significant,but the morphological characteristics of the population roots were largely different.Specifically,SDN significantly increased the morphological indexes of the root population such as root fresh weight,root volume,root number,root length and root dry weight.The effects of SDN on the total root absorption areas and root active absorption areas of the single plants were non-significant,but it dramatically enhanced the total root absorption areas and root active absorption areas of the plant population during the tillering,heading and mature stages.In addition,SDN significantly increased the root bleeding intensity and elevated the soluble sugar and free amino acid contents of root bleeding sap.Compared to the traditional cultivation pattern(CK),SDN significantly increased root bleeding intensity at the heading stage by 4.37 and 8.90% for early and late rice,respectively.Meanwhile,SDN profoundly enhanced the soluble sugar contents of root bleeding sap by 12.85 and 10.41% for early and late rice,respectively.In addition,SDN also significantly enhanced free amino acid content of root bleeding sap by 43.25% for early rice and by 37.50% for late rice systems compared to CK.Furthermore,SDN increased the actual yield of double cropping rice mainly due to the higher effective panicle number and the larger seedsetting rate.The actual yields of early rice under SDN were higher than CK by 9.37 and 5.98% in 2016 and 2017,and the actual yields of late rice under SDN were higher than CK by 0.20 and 1.41% in 2016 and 2017,respectively.Correlation analysis indicated that the significant positive correlations were observed between the majority of the root indexes and the actual yield across the four different growth stages.

Effects of Increased Planting Density with ReducedNitrogen Application on Yield Formation and NitrogenUtilization of Autumn Maize

With the change of cropping system in the middle reaches of the Yangtze River,the planting area of autumn maize is gradually increasing.However,the cultivation techniques are still under improvement for higher yield and nitrogen efficiency of autumn maize.Increase in planting density with reduced nitrogen fertilizer application is one of the important paths to achieve high yield and high nitrogen utilization efficiency.Meanwhile,the effect needs to be verified for autumn maize.The semi-compact autumn maize variety Qinyu 58 was planted under different planting densities and nitrogen fertilizer amounts with the split plot design.Different nitrogen application rates were arranged in the main plots,including the conventional nitrogen application(N300,300 kg/hm^2),30%reduction from the conventional treatment(N210,210 kg/hm^2)and no nitrogen application(N0).Different planting densities were arranged in the sub-split plots,including the conventional planting density(D60,60000 plants/hm2),medium density(D78,78000 plants/hm^2)and high density(D93,93000 plants/hm2).The effects of nitrogen fertilizer,planting density and their interaction effects on canopy structure,dry matter accumulation,yield and nitrogen use efficiency of autumn maize were studied.The nitrogen application rate and planting density had obvious interaction effects on the yield formation of autumn maize.Compared with the conventional cultivation(N300D60),increasing the planting density with 30%reduction in nitrogen application(N210)can obviously increase the canopy light interception rate,LAI,dry matter accumulation and yield.However,there was no significant change in canopy light interception rate,LAI,dry matter accumulation,grain weight and yield between D93 and D78.Compared with N300D60,nitrogen translocation efficiency and nitrogen contribution proportion to grain nitrogen did not change significantly in autumn maize grown under N210 and D78 treatments,whereas nitrogen partial productivity,nitrogen agronomic efficiency and recovery and utilization efficiency of nitrogen fertilizer increased significantly.Moreover,high density(D93)planting at N210 plots significantly improved nitrogen transport efficiency and utilization efficiency in autumn maize.Therefore,the suitable planting density of the autumn maize variety Qinyu 58 in Hubei Province is recommended a value of 78000 plants/hm^2,with the nitrogen application rate of 210 kg/hm2,which can achieve the target of higher yield by increasing density and reducing nitrogen.

Water,Nitrogen and Plant Density Affect the Response of Leaf Appearance of Direct Seeded Rice to Thermal Time

Field experiments were conducted in the Ebro Delta area （Spain）, from 2007 to 2009 with two rice varieties： Gleva and Tebre. The experimental treatments included a series of seed rates, two different water management systems and two different nitrogen fertilization times. The number of leaves on the main stems and their emergence time were periodically tagged. The results indicated that the final leaf number on the main stems in the two rice varieties was quite stable over a three-year period despite of the differences in their respective growth cycles. Interaction between nitrogen fertilization and water management influenced the final leaf number on the main stems. Plant density also had a significant influence on the rate of leaf appearance by extending the phyllochron and postponing the onset of intraspecific competition after the emergence of the 7th leaf on the main stems. Final leaf number on the main stems was negatively related to plant density. A relationship between leaf appearance and thermal time was established with a strong nonlinear function. In direct-seeded rice, the length of the phyllochron increases exponentially in line with the advance of plant development. A general model, derived from 2-year experimental data, was developed and satisfactorily validated; it had a root mean square error of 0.3 leaf. An exponential model can be used to predict leaf emergence in direct-seeded rice.

Effect of Fertilizing Amount and Planting Density on Yield and Qual-ity of Strong-gluten Wheat Taishan 27

To get the cultivation pattern featured by improved varieties and fine methods for strong-gluten and high-yielding wheat variety Taishan 27,this paper used Taishan 27 as material to study the effect of fertilizing amount and planting density on yield and quality of material.The results showed that Taishan 27 had high yield under fertilizing amount of 225 kg/ha pure nitrogen and planting density of 240 × 104-300× 10~4/ha; the yield was lowest under fertilizing amount of 300 kg/ha pure nitrogen and planting density of 360 × 10~4/ha. The suitable planting density for Taishan 27 was 240 × 104-300 × 10~4/ha,and the fertilizing amount of nitrogen should be based on different soil fertility conditions to avoid water and fertilizer stress and improve yield.

Effect of Fertilizing Level and Planting Densities on Yield and Nitrogen Utilization in Maize

Elite maize hybrid Guidan0810 was selected as material, and the effects of fertilizing level and planting densities on yield and nitrogen utilization were dis- cussed in the study. In field experiments as per double-cropping system, 4 main plots （fertilization levels） and 6 subplots （planting densities） were set in a split plot design. The results suggested that yield had close relationship with fertilization levels and planting densities. Different fertilization levels and planting densities significantly affected yield. With the increase of nitrogen fertilization, nitrogen use efficiency, nitrogen agronomic efficiency and nitrogen physiological efficiency declined. Under the same fertilization level, nitrogen use efficiency, nitrogen agronomic efficiency and nitrogen physiological efficiency grew a little with the increase of planting density, so nitrogen efficiency could be improved by regulating planting density. The results also showed that A2 （including N 225.0 kg/hm2, P205 75.0 kg/hm^2, K20 187.5 kg/hm^2） matching to B3 （52 500 plants/hm^2） or B4（60 000 plants/hm^2） was a better design, which could obtain a higher yield in the range of 7 913.2-8 207.8 kg/hm2, respectively.

Leaf Photosynthetic Characteristics of High-Yield Soybean[Glycine max(L.)Merr.]Under Different Planting Densities,Different Fertilization Rates,and Single/Mixed Planting Patterns

Understanding the photosynthetic characteristics of high-yield soybean[Glycine max(L.)Merr]cultivar(HYC)would aid research aiming at investigating the soybean high yield formation mechanism and optimization of cultivation system.To assess the photosynthesis of HYC,a pot experiment was conducted to quantify the differences in photosynthetic characteristics between HYC and common-yield soybean cultivar(CC)under different planting densities,fertilization rates,and single/mixed planting patterns.The leaf greenness(Lg),net photosynthetic rate(Ph),stomatal conductance(St)and transpiration rate(Tr)were significantly higher in HYC than CC mainly in seed-filling stages.HYC was more tolerant to dense and mixed planting because the decreases of Ph and St under high planting density and those of Ph,St,and Tr under mixed planting were lower in HYC than CC.The Lg and Ph in HYC were more superior to those in CC at high fertilization rate.Thus,the HYC has a superior performance in photosynthetic characteristics under the varied cultivation practices,which may contribute to the greater seed yield in HYC than CC.

Yield gap and production constraints of mango (Mangifera indica) cropping systems in Tianyang County, China

Mango is an important cash crop in the tropics and subtropics. Determining the yield gap of mango and production constraints can potentially promote the sustainable development of the mango industry. In this study, boundary line analysis based on survey data from 103 smallholder farmers and a yield gap model were used to determine the yield gap and production constraints in mango plantations in the northern mountain, central valley and southern mountains regions of Tianyang County, Guangxi, China. The results indicated that the yield of mango in three representing regions of Tianyang County,Northern Mountains, Central Valley and Southern Mountains, was 18.3, 17.0 and 15.4 t ha^–1 yr^–1, with an explainable yield gap of 10.9, 6.1 and 14.8 t ha^–1 yr^–1, respectively. Fertilization management, including fertilizer N, P2O5 and K2O application rates, and planting density were the main limiting factors of mango yield in all three regions. In addition, tree age influenced mango yield in the Northern Mountains(11.1%) and Central Valley(11.7%) regions. Irrigation time influenced mango yield in the Northern Mountains(9.9%) and Southern Mountains(12.2%). Based on a scenario analysis, the predicted yield would increase by up to 50%, and fertilizer N use would be reduced by as much as approximately 20%. An improved understanding of production constraints will aid in the development of management strategy measures to increase mango yield.

Does heat accumulation alter crop phenology, fibre yield and fibre properties of sunnhemp(Crotalaria juncea L.) genotypes with changing seasons?

Field experiments were carried out in split plot design during the dry and wet seasons for two years(two seasons each in 2016–2017 and 2017–2018) with two genotypes(SH4 and SUIN053), two plant geometry(30×15 cm and 45×15 cm main plots) and three levels of NPK(20 kg N ha^(–1), 40 kg P ha^(–1) and 40 kg K ha^(–1);20 kg N ha^(–1), 60 kg P ha^(–1) and 60 kg K ha^(–1);20 kg N ha^(–1), 80 kg P ha^(–1) and 80 kg K ha^(–1)) with an objective to study the relationship between fibre yield of sunhmep and thermal indices. The results indicated that the thermal units such as cumulative heat unit(CHU), photo thermal unit(PTU) and helio thermal unit(HTU) were the highest during dry seasons, while relative temperature disparity(RTD) was the highest during wet seasons irrespective of the genotypes, plant geometry and fertilizer levels. The combined analysis of variance showed that the suitability of sunnhemp genotypes for obtaining fibre and seed yields varied with season. The results further indicated that sunnhemp grew during dry seasons with longer photoperiod and higher values of growing degree days(GDD), HTU and PTU resulted in a higher fibre yield, while a higher seed yield and relatively longer, finer and stronger fibres were obtained during wet seasons with higher RTD values. Regression analysis indicated that CHU was positively related to fibre yield, while RTD was positively related to seed yield. CHU beyond 2 000 °C d reduced seed yield and favoured fibre production. In contrary to CHU, RTD values were positively related to seed yield and negatively related to fibre yield. Similarly, HTU had an inverse relationship with fibre yield while PTU had a positive relationship with fibre yield. The genotype SH4 produced a seed yield of 1 361 kg ha^(–1) during wet seasons, which was significantly higher than SUIN053, while a fibre yield of 990 kg ha^(–1)(significantly higher than that of SH4) was obtained for SUIN053 that required less CHU to attain the phenological events during dry seasons. The per unit area yields of seed and fibre with the closer spacing(30 cm×15 cm) by virtue of higher plant density were 17.0 and 14.9% higher than those with the spacing of 45 cm×15 cm, respectively. Higher doses of P and K resulted in higher seed and fibre yields.

The Agronomic Techniques as Determinants of the Phenolic Content and the Biological Antioxidant Effect of Palm-Tree Kale

The content of phytochemicals in vegetables is strongly affected by genetic, agronomic, and environmental factors, and by transportation and storage conditions, potentially affecting the sensory and putative health-promoting properties. In this study the impact of different agricultural techniques on the phenolics content and antioxidant activity of extracts from a traditional Italian kale landrace, called palm-tree kale (Brassica oleracea L., ssp. acephala DC, var. sabellica L.) was evaluated. Furthermore, the antioxidant effects of the different extracts were assessed in a biological system using primary cultures of neonatal rat cardiomyocytes. The final aim was to evidence whether and how the agronomic practices can affect the antioxidant properties of kale not only in vitro but also in cells. Results herein reported underline the influence of the crop production strategies in establishing the potential health benefits of a vegetable. This research approach could be useful for the selection of production techniques that are able to provide edible vegetables with higher functional activity, and evidences the need to study the food domain as a whole with the nutrition domain, and to integrate all results in order to have an overall “foodomics” vision allowing the improvement of health and well-being.

Integrating phosphorus management and cropping technology for sustainable maize production

Achieving high maize yields and efficient phosphorus(P)use with limited environmental impacts is one of the greatest challenges in sustainable maize production.Increasing plant density is considered an effective approach for achieving high maize yields.However,the low mobility of P in soils and the scarcity of natural P resources have hindered the development of methods that can simultaneously optimize P use and mitigate the P-related environmental footprint at high plant densities.In this study,meta-analysis and substance flow analysis were conducted to evaluate the effects of different types of mineral P fertilizer on maize yield at varying plant densities and assess the flow of P from rock phosphate mining to P fertilizer use for maize production in China.A significantly higher yield was obtained at higher plant densities than at lower plant densities.The application of single superphosphate,triple super-phosphate,and calcium magnesium phosphate at high plant densities resulted in higher yields and a smaller environmental footprint than the application of diammonium phosphate and monoammonium phosphate.Our scenario analyses suggest that combining the optimal P type and application rate with a high plant density could increase maize yield by 22%.Further,the P resource use efficiency throughout the P supply chain increased by 39%,whereas the P-related environmental footprint decreased by 33%.Thus,simultaneously optimizing the P type and application rate at high plant densities achieved multiple objectives during maize production,indicating that combining P management with cropping techniques is a practical approach to sustainable maize production.These findings offer strategic,synergistic options for achieving sustainable agricultural development.

Optimal Technique for High Yield of Purple Flesh Sweetpotato in Chongqing

[Objective] The aim was to obtain the best planting density and the best fertilizer of purple flesh sweetpotato so as to provide theoretical basis for breeding of high yield and quality of purple flesh sweetpotato in Chongqing.[Method] The effects of fertilization,planting density and variety on yield of purple flesh sweetpotato were studied by orthogonal test of L9（34）.Residential treatment was：fertilization（A）,300 kg/hm2（A1）,600 kg/hm2（A2）,900 kg/hm2（A2）;density（B）,45 000 Plants/hm2（B1）,60 000 Plants/hm2（B2）,75 000 Plants/hm2（B3）;species（C）,Wanzi 56（C1）,Yuzi 43（C2）,Yuzi 263（C3）.[Result] The yield of Wanzi 56 was the highest among three purple flesh cultivars on conditions that planting density was 75 000 plants/hm2,and fertilization was 300 kg/hm2.The influence of planting density for yield of purple flesh sweetpotato was higher than that of fertilization.The orders of different levels of various factors on the test results was A factor column,K1〉K2〉K3;B factor column,K3〉K1〉K2;C factors column,K1〉K3〉K2.[Conclusion] The yield of Wanzi 56 was highest,follow by the yizi263 and yuzi43.The optimum planting density was 75 000 plants/hm2,and the most reasonable amount of fertilizer was 300 kg/hm2.

N, P and K use efficiency and maize yield responses to fertilization modes and densities

Optimal planting density and proper fertilization method are important factors to improve maize yield and nutrient utilization. A two-year(2016 and 2017) field experiment was conducted with three plant densities(6.0, 7.5 and 9.0 plants m^-2) and three fertilization modes(no fertilizer, 0 F;one-off application of slow-released fertilizer, SF;twice application of conventional fertilizer, CF). Results indicated that the grain yields and N, P and K use efficiencies under SF with the optimal planting density(7.5 plants m^-2) were the highest among all the treatments in 2016 and 2017. Compared with CF, SF could increase post-silking dry matter accumulation and promote N, P and K uptake at pre-and post-silking stages;this treatment increased grain N, P and K concentrations and resulted in high N, P and K use efficiencies. Nutrient(N, P and K) absorption efficiencies and partial productivity, and nutrient(N and P) recovery efficiency in SF treatment were significantly higher than those in CF treatments under the planting density of 7.5 plants m^-2. Under both SF and CF conditions, the grain yield, total N accumulation and nutrient use efficiencies initially increased, peaked at planting density of 7.5 plants m^-2, and then decreased with increasing plant density. Based on the yield and nutrient use efficiency in two years, plant density of 7.5 plants m^-2 with SF can improve both the grain yield and N, P and K use efficiency of spring maize in Jiangsu Province, China.

The priority of management factors for reducing the yield gap of summer maize in the north of Huang-Huai-Hai region, China

Understanding yield potential, yield gap and the priority of management factors for reducing the yield gap in current intensive maize production is essential for meeting future food demand with the limited resources. In this study, we conducted field experiments using different planting modes, which were basic productivity(CK), farmer practice(FP), high yield and high efficiency(HH), and super high yield(SH), to estimate the yield gap. Different factorial experiments(fertilizer, planting density, hybrids, and irrigation) were also conducted to evaluate the priority of individual management factors for reducing the yield gap between the different planting modes. We found significant differences between the maize yields of different planting modes. The treatments of CK, FP, HH, and SH achieved 54.26, 58.76, 65.77, and 71.99% of the yield potential, respectively. The yield gaps between three pairs: CK and FP, FP and HH, and HH and SH, were 0.76, 1.23 and 0.85 t ha^(–1), respectively. By further analyzing the priority of management factors for reducing the yield gap between FP and HH, as well as HH and SH, we found that the priorities of the management factors(contribution rates) were plant density(13.29%)>fertilizer(11.95%)>hybrids(8.19%)>irrigation(4%) for FP to HH, and hybrids(8.94%)>plant density(4.84%)>fertilizer(1.91%) for HH to SH. Therefore, increasing the planting density of FP was the key factor for decreasing the yield gap between FP and HH, while choosing hybrids with density and lodging tolerance was the key factor for decreasing the yield gap between HH and SH.

Relationships between Tree Diameter,Height,and Stocking in Even-Aged Eucalypt Stands in Pointe-Noire(Republic of Congo)

The study highlights the complex dynamics governing the growth of forest stands,particularly in eucalyptus plantations in Congo.Factors such as soil fertility,planting density,clone genetics,and resource competition significantly influence forest productivity.Thinning practices,when well implemented,help to rebalance competition among trees and maximize diameter growth.However,forest growth models,like Vanclay’s model,must be adapted to local conditions to provide more accurate and relevant predictions.Despite the progress made,questions remain about the best way to optimize forest stand management.The use of more sophisticated models that can account for the diversity of ecological conditions and management practices represents a major challenge for researchers and forest managers.

A practical approach to improve alarm system performance: Application to power plant

Process safety in chemical industries is considered to be one of the important goals towards sustainable development. This is due to the fact that, major accidents still occur and continue to exert significant reputational and financial impacts on process industries. Alarm systems constitute an indispensable component of automation as they draw the attention of process operators to any abnormal conditi on in the plant. Therefore, if deployed properly, alarm systems can play a critical role in helping plant operators ensure process safety and profitability. How-ever, in practice, many process plants suffer from poor alarm system configuration which leads to nuisance alarms and alarm floods that compromise safety. A vast amount of research has primarily focused on developing sophisticated alarm management algorithms to address specific issues. In this article, we provide a simple, practical, systematic approach that can be applied by plant engineers (i.e., non-experts) to improve industrial alarm system performance. The proposed approach is demonstrated using an industrial power plant case study.

施肥量与种植密度对田润189玉米主要农艺性状及产量的影响

以自主选育玉米新品种田润189为试验材料,采用二因素裂区试验设计,主区为种植密度,设3个密度水平处理(A1处理42000株/hm^(2);A2处理48000株/hm^(2);A3处理54000株/hm^(2)),副区为施肥量,设4个施肥水平处理(B1处理为常规施肥,施用复合肥750 kg/hm^(2)和尿素150 kg/hm^(2);B2、B3和B4处理分别施用缓释肥600、750和900 kg/hm^(2)),探究田润189在3个密度4个施肥量水平条件下玉米主要农艺性状、产量及经济效益的表现。结果表明,种植密度、施肥量及肥密互作对植株性状、果穗性状及产量均存在显著或极显著影响。在不同种植密度条件下,田润189的产量以A3处理最高,且显著或极显著高于A1处理,但与A2处理差异不显著;在不同施肥量条件下,田润189的产量以B4处理最高,且极显著高于B2处理,但与B3和B1处理差异不显著;在肥密互作中,春播以A3B1处理的产量最高,达8494.50 kg/hm^(2)且显著高于A3B2处理,但与A3B4和A3B3处理差异不显著,而秋播以A3B4处理的产量最高(8276.50 kg/hm^(2)),显著高于A3B2处理,但与A3B1和A3B3处理差异不显著。从经济效益上看,施用缓释肥处理(B2、B3和B4处理)的收益均比常规施肥处理(B1处理)高,尤其B3处理的收益最高,达12353.59元/hm^(2),比B1处理平均增收10.77%。综上所述,田润189玉米的较佳种植密度为48000~54000株/hm^(2),在此密度下施用750~900 kg/hm^(2)缓释型复合肥(N-P 2O 5-K 2O=24-6-10)可获得较佳的产量和经济效益。

增密与减氮对青贮玉米产量的影响

以郑青贮1号、北农青贮368和郑单958为试验材料,研究了施氮量、种植密度及品种互作对青贮玉米鲜草产量和干物质生物产量的影响。结果表明:品种(郑青贮1号、北农青贮368、郑单958)、施氮量(N_(1)、N_(2)、N_(3)分别为240、216、168 kg/hm^(2))和密度(D_(1)、D_(2)、D_(3)、D4分别为6.75万、7.50万、8.25万、9.00万株/hm^(2))对青贮玉米干物质生物产量和鲜草产量均有显著的影响,在相同的密度水平下,3个玉米品种的干物质生物产量随施氮量的减少,总体呈下降趋势,但是N_(1)和N_(2)处理之间无显著差异;在相同施氮水平下,3个玉米品种的干物质生物产量随密度的增加,总体呈现先上升后下降的趋势;在不同施氮量和种植密度条件下,正常施氮量且高密度种植条件下(N_(1)D_(3)、N_(1)D4)的产量表现为郑青贮1号>北农青贮368>郑单958;在正常施氮量且低密度种植(N_(1)D_(1)、N_(1)D_(2))和减氮条件下(N_(2)、N_(3))的产量表现为北农青贮368>郑青贮1号>郑单958。因此,综合考虑减氮增产高效的目标,氮肥减施10%(N_(2))的条件下,郑青贮1号和北农青贮368的推荐栽植密度为8.25万株/hm^(2),郑单958不推荐作为青贮玉米种植。

种植密度与施肥水平对甜荞光合特性、产量及抗倒伏的影响

【目的】合理密植与施肥,可有效协调个体间的竞争,改善群体光环境,构建高产群体,是提高作物高产的重要途径。探讨不同种植密度和施肥水平对甜荞抗倒性能及产量的影响,为荞麦抗倒高产高效栽培提供技术参考。【方法】以等花柱甜荞新品种西农D4103为试验材料,黄土高原主栽品种西农9976为对照,采用双因素裂区设计,主因素为2个栽培密度,分别为D1:90万株/hm2、D2:135万株/hm2;副因素为低、中、高3个施肥水平,分别为F1(N:120、P2O5:76.8、K2O:56.4 kg·hm^(-2))、F2(N:180、P2O5:115.2、K2O:84.6 kg·hm^(-2))和F3(N:240、P2O5:153.6、K2O:112.8 kg·hm^(-2)),于2021—2022年在西北农林科技大学榆林小杂粮试验站进行。研究不同种植密度和施肥水平对甜荞群体冠层结构及光合特性、产量及产量构成因素、倒伏特性的变化规律。【结果】2年大田试验表明,提高种植密度,使甜荞群体叶面积指数(LAI)显著增加,光合有效辐射(PAR)和相对叶绿素含量(SPAD)显著下降,并减弱了叶片光合能力。施肥显著提高了甜荞群体LAI、SPAD和光合能力,降低了PAR,中肥水平较低肥水平的LAI、SPAD、净光合速率(Pn)、气孔导度(Gs)和蒸腾速率(Tr),平均增加14.6%、6.7%、15.3%、15.2%和16.6%,PAR和胞间CO_(2)浓度(Ci)平均减少4.5%和6.7%。D2较D1处理的株高、重心高度、第2节间长、倒伏率和倒伏指数平均增加9.6%、12.5%、24.7%、19.8%和26.2%,而第2节间粗、充实度、抗折力和整株鲜重减少13.1%、7.4%、18.3%和8.5%。同等密度下增加施肥量,使甜荞株高、重心高度、第2节间长、整株鲜重、倒伏率和倒伏指数逐渐增加,第2节间粗、第2节间充实度、第2节间抗折力呈先增加后减小的趋势。提高种植密度和施肥水平,使甜荞产量显著增加,西农D4103的产量在D2F2处理下达最大值,较D1F1增产15.1%,较对照品种在同等施肥量下增产17.0%。【结论】构建合理的甜荞群体结构有利于增加群体受光面积,改善光合特性,降低田间倒伏率,从而提高产量。因此,黄土高原地区等花柱甜荞品种西农D4103推荐种植密度为135万株/hm2,肥料施用量为中等施肥水平(N:180 kg·hm^(-2)、P2O5:115.2 kg·hm^(-2)、K2O:84.6 kg·hm^(-2))。

种植密度与施肥量对白城地区甜荞农艺性状及产量的影响

探究白城地区甜荞生产的最佳种植密度和施肥量。采用4个种植密度和5个施肥量2个因素的随机区组设计,研究了不同种植密度和施肥量对甜荞农艺性状及产量的影响。结果表明,在低种植密度条件下株高随施肥量的增加而增加;各处理间主茎节数没有明显的差异;分枝数在低种植密度75万株/hm^(2)时随施肥量的增加而增加,各处理间差异不明显。株粒数、株粒重和千粒重在M1(75万株/hm^(2))密度条件下随着施肥量的增加而增加。株高在无施肥条件下随密度的增加而增加,在施肥量400 kg/hm^(2)时随密度的增加而减小;各处理间分枝数无显著的变化。综上,白城地区甜荞最适种植密度为125万株/hm^(2),最佳施肥量为300 kg/hm^(2)。

2种新型肥料对大豆肥密效应及土壤酶活的影响研究

为研究2种新型肥料及其配套施用方法对大豆肥密效应及土壤酶活的影响,本研究以‘中龙豆120’为试验材料,设置6个施肥处理(空白施肥、正常施肥、低浓度硫代硫酸铵、高浓度硫代硫酸铵、0.5肥+铜大师、0.3肥+铜大师,分别记作T_(1)、T_(2)、T_(3)、T_(4)、T_(5)、T_(6))为主区和3个种植密度水平(15×10^(4)、20×10^(4)、25×10^(4)株/hm^(2),分别记作M1、M2、M3)为副区进行裂区试验。结果表明:在同一施肥处理下,大豆产量随种植密度的增加先上升后下降,在M2处取得最大值;随着种植密度的增加,主茎粗、叶绿素含量逐渐减少,株高、叶面积指数逐渐增大。在同一种植密度下,硫代硫酸铵处理较T_(1)、T_(2)相比增加了产量、叶面积指数、土壤蔗糖酶和碱性磷酸酶活性,但是降低了大豆株高、主茎粗与土壤脲酶活性,T_(3)处理较T_(1)、T_(2)相比均增加了叶绿素含量,T_(4)较T_(1)相比增加了叶绿素含量;铜大师处理在M3密度下种植时相对T_(1)、T_(2)显著提高大豆产量但此时与其他种植密度相比整体产量较低,铜大师处理下大豆株高、主茎粗、叶面积指数及土壤酶活性趋势整体上均低于T_(1)、T_(2),叶绿素含量呈相反的结果。综上所述:20万株/hm^(2)时硫代硫酸铵处理是最优栽培模式,且在M_(2)T_(4)下达到产量最大值3200.00 kg/hm^(2),铜大师在大豆上的应用我们应做下一步探索。