适宜氮磷钾用量和配比协同促进盆栽牡丹营养和生殖生长

【目的】牡丹是我国著名的木本观赏植物,施肥不平衡严重影响盆栽牡丹的生长和观赏效果。研究开花前后氮、磷、钾不同施用量和配施比例对盆栽牡丹生长的影响,确定适宜的氮、磷、钾施用量及配比,为盆栽牡丹精准施肥提供理论依据。【方法】本研究以5年生牡丹‘紫二乔’为供试材料,采用“3414”不完全正交回归设计进行盆栽试验,结合隶属函数法评价牡丹的生长状况,利用肥料效应模型拟合牡丹植株的综合隶属函数值与施肥量之间的数学关系,得出牡丹最佳生长的氮、磷、钾肥推荐施肥量。【结果】牡丹开花前后施用氮磷钾肥显著影响植株株高、茎粗、冠幅、花径和单株花数(P<0.05),适宜氮磷钾用量和配比促进盆栽牡丹营养和生殖生长的协同提高。氮、磷、钾三因素配合处理的牡丹综合隶属函数值均大于缺素处理,缺素处理又大于无肥处理,N_(2)P_(2)K_(2)处理的综合隶属函数值(0.73)是N_(0)P_(0)K_(0)的3.17倍。氮磷钾对牡丹综合生长的影响表现为氮>磷>钾。氮、磷、钾肥对牡丹营养和生殖生长存在明显交互作用,任一肥料水平的过量或不足均会抑制牡丹植株生长,降低观赏效果。采用一元二次、二元二次、三元二次肥料效应函数方程拟合牡丹的综合隶属函数值和施肥量,二者相关性均达显著水平,综合各肥料效应函数方程的推荐用量及相应的综合隶属函数值,得出牡丹开花前后氮(N)、磷(P_(2)O_(5))、钾(K_(2)O)的最优推荐施肥量分别为4.21、2.07、2.52 g/株,适宜的氮、磷、钾施肥比例为1∶0.49∶0.60。【结论】开花前后施用适量的氮、磷、钾肥可提高牡丹的农艺性状,促进牡丹的营养和生殖生长协同提高。氮、磷、钾的最优推荐施肥量为4.21、2.07、2.52 g/株,适宜的氮、磷、钾施肥比例为1∶0.49∶0.60。

Nutrient Response Functions of Sorghum for Miesso District Central Rift Valley of Ethiopia

This study was executed to offer the basis for optimized profit from fertilizer use for sorghum yield and to determine robust crop nutrient response function and economic rate for the production of sorghum at Miesso Central Rift Valley of Ethiopia. Trails were conducted at six experimental sites, sorghum yield response to N and P fertilizers application and economically optimum rates of nitrogen (EONR) and phosphorus (EOPR) were evaluated on a vertisols within the semi-arid Miesso districts west Hararge zone of Oromia region. The nutrient rates in 2014 cropping season four levels of Nitrogen (N) alone, these levels with 20 kg·ha−1 Phosphorus (P) and without N, 69 kg·ha−1 N with three levels of P treatments including the zero control were evaluated. In 2015, cropping season similar rates of N alone, the same rate N with 20 kg·ha−1 P, 92 kg·ha−1 N with three rates of P including the zero control were evaluated. The treatments were arranged in a randomized complete block with three replications in factorial design. Nutrient responses of sorghum were determined using asymptotic quadratic plateau functions. The significantly highest nitrogen rate was 46 kg·ha−1 alone in 2014 season, which gave grain yield of 2.56 Mg·ha−1 with a maximum yield advantage of 43%. P rates in both seasons and combined (sites + seasons) were not significantly influenced sorghum yield. Nitrogen agronomic and partial factor productivity peaked at 23 kg N ha−1 but declined with increasing N rate. The EONR combined (sites + seasons) were 37, 45, 52 and 60 kg·ha−1 and for the profit to cost ratio (PCR) were 2.43, 3.65, 4.86 and 5.79 at difference cost to grain price ratios (CP) = 3.6, 2.3, 1.6 and 1.2 respectively at Miesso Ethiopia. Nitrogen application had economically profitable than P. The study concluded that the application of N at 37 or 60 kg N ha−1 to sorghum production could be economically profitable for those economically constrained farmers or economically not constrained farmers. Validation should be farther conducted on farmers’ fields for refining the results obtained.

Optimizing Nutrient Use Efficiency and Returns from Soybean Production under Smallholders in Three Agro-Ecologies of Malawi

Field trials were conducted to determine the economically optimum fertilizer rates for soybean production and for optimizing net profits in Dedza, Lilongwe and Salima Districts of Malawi. The effects of PK fertilizer rates on rain use efficiency (RUE), harvest index, agronomic use efficiency of phosphorous (AEP) and potassium (AEK), and value cost ratio (VCR) were evaluated. The applied diagnostic PK fertilizer rates significantly improved soybean grain yields, harvest index, rainwater use efficiency, AEP, AEK and returns to fertilizer use expressed as value cost ratio (VCR). However, the results differed significantly

上海地区典型设施菜地的生菜适宜施氮量研究

在设施大棚种植条件下,采用田间小区试验方法研究了不同施氮处理对生菜产量、品质及氮素利用率的影响。结果表明,与农民习惯施氮量150 kg·hm-2相比,减少20%的氮素用量能保持生菜的产量和氮素利用率,维持蔬菜品质。施氮120 kg·hm-2能使大棚生菜产量增加至5 353 kg·hm-2,氮素利用率达17.8%,净收入达12 091元·hm-2。生菜的叶片数、株高、生物量以及可溶性糖含量也在施氮120 kg·hm-2时最高。生菜叶片中的硝酸盐的积累与施氮量呈明显的正相关性,减少施氮能有效抑制生菜叶片中硝酸盐的积累。综合产量效益和经济效益等因素,对上海地区土壤含氮量较高的大棚,推荐生菜适宜施氮量为120 kg·hm-2。

基于秸秆还田视角的化肥减施潜力研究——以湖北省为例

目的:弄清湖北省农作物秸秆资源数量及其养分资源量,旨在为合理利用秸秆资源、实现化肥减施、提高肥料利用率、和保障粮食安全提供科学依据。方法:研究通过调查、查阅统计年报、分析相关研究、及文献资料,对湖北省2016年~2018年农作物秸秆资源量进行了估算、并分析替代化肥的潜力。结果:结果表明湖北省农作物秸秆资源量为3842万t,可提供的氮、磷、钾养分资源为110.19万t,秸秆资源以水稻最多,主要分布在湖北省粮棉油主产区,以襄阳市最多。结论:湖北省目前农作物理论化肥需求量290万t,如以秸秆还田为措施保障,目前可基本满足化肥用量减少20%,减量目标具有一定科学依据,但有减产风险;秸秆资源利用需以“农用优先、还田为主”为主导原则。

基于川麦冬皂苷和黄酮成分的氮磷钾化肥与有机肥适宜配比

【目的】研究氮磷钾无机肥与有机肥配施对川麦冬主要有效成分含量的影响及肥料的适宜施用量。【方法】田间试验采用四元二次正交旋转组合设计,在川麦冬生长期分3次施用氮肥、磷肥、钾肥与有机肥,采收后分别测定药材的麦冬皂苷D(OSD)、麦冬皂苷D′(OSD′)、麦冬甲基黄烷酮A(MONA)、麦冬甲基黄烷酮B(MONB)和麦冬黄烷酮D(MOND)的含量。利用模型分析氮磷钾肥与有机肥对川麦冬主要有效成分含量的影响,利用统计频数法综合各项指标获得最优施肥方案。【结果】氮磷钾肥与有机肥合理配施对OSD、OSD′和MONA含量的影响显著,对MONB与MOND含量的影响不明显。肥料对活性成分的影响程度也不同,钾肥主要影响OSD′、MONA与MONB的含量,有机肥主要影响OSD含量,氮肥主要影响MOND的含量。随着钾肥用量的增加,OSD含量逐渐增加,OSD′的含量先下降后升高。氮肥有机肥互作有利于OSD的积累,钾肥与有机肥互作不利于OSD′的积累;氮肥与磷肥互作、钾肥与有机肥互作有利于MONA的积累,氮肥与钾肥互作、磷肥与钾肥互作、磷肥与有机肥互作不利于MONA的积累。通过优化分析,施用N 307~368 kg/hm^(2)、P_(2)O_(5)23~27 kg/hm^(2)、K_(2)O 189~190 kg/hm^(2)、有机肥2419~2534 kg/hm^(2)可使OSD含量≥140μg/g、OSD′含量≥75μg/g、MONA含量≥100μg/g。【结论】获得最高麦冬皂苷D含量的施肥量为N 332 kg/hm^(2)、P_(2)O_(5)25 kg/hm^(2)、K_(2)O 204 kg/hm^(2)、有机肥2616 kg/hm^(2)。获得最高麦冬皂苷D′含量的施肥量为N 339 kg/hm^(2)、P_(2)O_(5)25 kg/hm^(2)、K_(2)O 199 kg/hm^(2)、有机肥2352 kg/hm^(2)。获得最高麦冬甲基黄烷酮A含量的施肥量为N 339 kg/hm^(2)、P_(2)O_(5)25 kg/hm^(2)、K_(2)O 173 kg/hm^(2)、有机肥2400 kg/hm^(2)。氮磷钾肥与有机肥合理配施可提高川麦冬中皂苷类和黄酮类成分的含量,尤其是麦冬甲基黄烷酮A和麦冬甲基黄烷酮B的含量。

春玉米“3414+1”肥效试验初报

为获得最佳经济产量时的施肥方案,采用"3414+1(锌)"试验设计方案建立肥料效应函数,分析不同施肥水平及锌肥对玉米产量、土壤供氮磷钾养分能力、土壤氮磷钾养分校正系数、植株对养分吸收量和当季肥料利用率的影响,并对最佳施肥方案进行验证与大田示范。结果表明:(1)产量限制因子的强弱依次为:氮>钾>磷;(2)最佳施肥量为N 190.1 kg/hm^2,P_2O_5 44.9 kg/hm^2,K_2O 135.1 kg/hm^2;(3)施用30 kg/hm^2七水硫酸锌玉米可增产3.22%;(4)该类型土壤N、P_2O_5、K_2O养分校正系数分别为0.44、0.24、0.53,N、P_2O_5、K_2O当季利用率分别为39.6%、1.83%、26.4%。试验所获得的最佳施肥方案是可行的,可在与试验地地域环境相似且地力相近的地块作春玉米栽培时推广实施。此外,玉米施用七水硫酸锌30 kg/hm^2增产效果好,建议每3 a施用1次。

玉米不同供肥强度和施肥配比下养分的吸收与利用

应用氮磷等比和以磷定氮两种试验方案统一在同一试验中进行的设计方法,对施肥比例与最大施氮量的关系及氮磷养分的吸收利用进行了研究。结果表明,氮磷比例显著影响最高产量施氮量的试验结果,同时也显著影响氮磷养分的吸收和利用。氮磷等比条件下的最大施氮量范围内,玉米按比例吸收氮磷养分并有效转化,氮肥的利用率和生理利用率都比较高;而以磷定氮下土壤氮磷养分的不平衡供应则导致玉米对氮磷养分的不平衡吸收和转化,从而使玉米的产量水平降低。