氮磷钾钙配施对望天树幼苗生长及生理特性的影响

探讨不同N、P、K、Ca配施处理对望天树幼苗生长及生理特性的影响，并根据其生长及生理表现筛选适宜的配施处理，旨在为望天树壮苗培育提供参考依据。以1年生望天树幼苗为试验材料，采用L16(4⁴)正交试验设计方法。结果表明，不同配施处理对望天树幼苗生长及生理指标影响达到极显著差异水平（P<0.01），生长表现最优处理是N₂P₂K₄Ca₁和N₃P₄K₂Ca₁，生理指标表现最优处理是N₃P₂K₁Ca₂和N₃P₄K₂Ca₁。相关性分析表明望天树苗高与叶片叶绿素、可溶性糖和可溶性蛋白质含量等生理指标呈极显著正相关，与丙二醛含量呈极显著负相关，地径仅与叶绿素含量呈显著正相关关系。处理7(100 mg N+20 mg P+80 mg K)、处理12（200 mg N+40 mg P+20 mg K）对望天树幼苗生长的促进作用最大，处理11（200 mg N+20 mg P+50 mg Ca）和处理12（200 mg N+40 mg P+20 mg K）配施下生理特性指标表现最好；N是望天树幼苗生长的必须因子，P和K对促进苗木地径生长作用显著，适量Ca有助于提高望天树幼苗生理活性，超过100 mg则导致生理胁迫。     

振捣提浆与侧深施肥技术模式对寒地水稻产量性状及肥水效率的影响

为解决北方寒地传统搅浆平地耕作模式造成稻田泡田灌溉水量大和肥料利用效率低等问题,于2018—2019年以稻田水整地环节振捣提浆机与侧深施肥机为材料,采用2种耕整地模式和2种施肥模式的正交试验设计：搅浆平地耕整地模式(WPF)、振捣提浆耕整地模式(VEP)、基肥撒施模式(CFA)和侧深施肥模式(SDF),分析振捣提浆+侧深施肥技术模式对泡田期灌水量、干物质积累量、产量指标、肥料利用率及经济效益的影响。结果表明：与常规搅浆平地耕整地+基肥撒施(WPF+CFA)相比,搅浆平地耕整地+侧深施肥(WPF+SDF)、振捣提浆耕整地+基肥撒施(VEP+CFA)和振捣提浆耕整地+侧深施肥(VEP+SDF)3种技术模式对水稻泡田灌溉量、产量性状、肥料利用效率和经济效益均产生显著的影响,以VEP+SDF增幅最大,WPF+SDF次之,VEP+CFA最小。与WPF+CFA相比,VEP+SDF模式能显著提高肥水效率,节约泡田灌溉水11.4%,减少肥料施用量10%,产量和经济效益分别提高7.3%和1628.7元/hm²。本研究表明,VEP+SDF模式显著改善肥水利用效率,提高植株产量和经济效益,是北方寒地水稻较为理想的机械化整地施肥技术模式。     

史密斯桉造林密度与施肥模式研究

针对史密斯桉造林密度与施肥模式进行了研究，对试验地设置3种造林密度作主区，4种施肥模式作副区。对17个月生史密斯桉的试验调查进行分析，结果表明：造林密度对树高生长量的影响差异不显著，而对胸径影响差异显著，适宜密度为2000株·hm^-2。施肥对史密斯桉幼树树高、胸径生长的影响极显著，不同的施肥模式对史密斯桉幼林生长的效果是：桉树专用肥>复混肥+微肥>复混肥+磷肥+微肥>复混肥+磷肥。     

Organic farming fosters agroecosystem functioning in Argentinian temperate soils: Evidence from litter decomposition and soil fauna

Benefits of organic farming on soil fauna have been widely observed and this has led to consider organic farming as a potential approach to reduce the environmental impact of conventional agriculture. However, there is still little evidence from field conditions about direct benefits of organic agriculture on soil ecosystem functioning. Hence, the aims of this study were to compare the effect of organic farming versus conventional farming on litter decomposition and to study how this process is affected by soil meso- and macrofauna abundances. Systems studied were: (1) organic farming with conventional tillage (ORG), (2) conventional farming with conventional tillage (CT), (3) conventional farming under no-tillage (NT), and (4) natural grassland as control system (GR). Decomposition was determined under field conditions by measuring weight loss in litterbags. Soil meso- and macrofauna contribution on decomposition was evaluated both by different mesh sizes and by assessing their abundances in the soil. Litter decomposition was always significantly higher after 9 and 12 months in ORG than in CT and NT (from 2 to 5 times in average), regardless decomposer community composition and litter type. Besides, mesofauna, macrofauna and earthworm abundances were significantly higher in ORG than in NT and CT (from 1.6 to 3.8, 1.7 to 2.3 and 16 to 25 times in average, respectively for each group). These results are especially relevant firstly because the positive effect of ORG in a key soil process has been proved under field conditions, being the first direct evidence that organic farming enhances the decomposition process. And secondly because the extensive organic system analyzed here did not include several practices which have been recognized as particularly positive for soil biota (e.g. manure use, low tillage intensity and high crop diversity). So, this research suggests that even when those practices are not applied, the non-use of agrochemicals is enough to produce positive changes in soil fauna and so in decomposition dynamics. Therefore, the adoption of organic system in an extensive way can also be suggested to farmers in order to improve ecosystem functioning and consequently to achieve better soil conditions for crop production.     

施肥方式对沃柑果实产量和外观品质的影响

为验证沃柑测土配方施肥的效果,推进化肥减量增效,探究有机肥、中微量元素肥料与化肥配施对沃柑果实产量和外观品质的效应,在沃柑园设置随机区组小区精确试验,试验处理包括当地习惯施肥、测土配方推荐施肥、优化施肥、优化施肥兼叶面喷施0.2%硼酸、优化施肥兼叶面喷施0.05%钼酸铵、优化施肥兼叶面喷施4%硫酸镁。结果表明,测土配方推荐施肥相较于习惯施肥增产效果显著。在同等养分施用量的情况下,用有机肥代替部分化肥处理与全化肥处理比较产量无显著差异,但前者比后者增效4.03%。在土壤交换性镁贫乏的情况下,沃柑叶面施镁可以获得极显著而稳定的增产效果。在土壤不缺硼的情况下,叶面施硼可能无效。在土壤有效钼不足时沃柑叶面施钼能够增产,但连年施用效果不稳定。由此可见,伴随果实外观品质的提升,化肥减量增效在沃柑生产上是可行的;沃柑施肥的增产潜力较大,如果配方和选材得当,可以发挥更大效益。     

浅析科学施肥

肥料对农作物增长、稳产、高产非常重要,就科学施肥的意义以及施肥中常见的问题做以分析,提出科学施用化肥方法,提高肥料利用率。     

农户过量施用化肥行为的影响因素分析——以新疆棉花种植户为例

过度施用化肥带来的负外部性使棉区土壤面临着棉花增产和保护生态环境的双重挑战。本文在棉花生产的决策主体农户尺度上,利用对新疆重点植棉地区实地问卷调查所得数据,定量化研究了新疆棉农过度施用化肥程度,并通过经济计量模型分析了导致农户过量施用化肥的主要因素。研究结果表明,新疆棉花种植农户的化肥施用量(折纯量)平均达到610.20 kg·hm~(-2),过量施用率占到实际施用量的59.6%。导致农户过量施用化肥的主要因素是缺乏科学施肥培训和避免收入损失的盲目性。研究结果在农户行为学方面做了有益的科学探讨,并为科学引导农户合理施肥提供了科学依据。     

长期定位施不同氮源有机肥替代部分含氮化肥对陇东旱塬冬小麦产量和水分利用效率的影响

在陇东黄土旱塬覆盖黑垆土大田,利用陇鉴301进行了连续10年的定位试验,观测长期施用不同氮源有机肥(发酵有机肥、农家肥)或小麦秸秆还田各处理对冬小麦产量相关性状和水分利用效率的影响。结果显示,小麦产量和水分利用效率年际间变化较大,与降雨量有直接关系;不同有机氮源替代部分含氮化肥处理对提高冬小麦产量和水分利用效率具有明显作用。在干旱、平水和丰水年型,较不施肥对照分别增产53.1%~103.7%、40.3%~79.3%和73.1%~94.8%,较单施化肥对照分别增产6.6%~41.8%、7.0%~36.8%和-2.9%~9.3%。以发酵有机肥做替代物处理的产量和水分利用效率最高,增产幅度最大,10年平均产量较不施肥和单施化肥对照分别增加88.9%和25.4%,水分利用效率和边际水分利用率也最高,分别为10.8 kg mm~(-1) hm~(-2)和1.03 kg m~(-3);并且产量构成因素和植株生理指标也优于其他处理。因此,发酵有机肥是陇东半湿润偏旱雨养农业区(年降水量约550 mm)冬小麦生产上替代部分含氮化肥的首选有机氮源。     

Radiation interception and radiation use efficiency of potato affected by different N fertigation and irrigation regimes

Three years of field experiments were carried out to explore the response of potato dry matter production, accumulated intercepted photosynthetic active radiation (Aipar) and radiation use efficiency (RUE) to five N levels providing 0, 60, 100, 140 and 180 kg N ha⁻¹ and three drip irrigation strategies, which were full, deficit and none irrigation. Results showed that, irrespective of years, dry matter production and Aipar were increased by prolonged N fertigation, even though N fertigation was carried out from middle to late growing season. The highest total and tuber dry matter and accumulated radiation interception in all three years were obtained when potatoes were provided with 180 kg N ha⁻¹. RUE on the other hand was not affected by N regime. Thus, increases in total dry matter production with increasing N levels were essentially caused by higher Aipar. The strongest response to N fertilization occurred when most N was applied early in the growing season and the latest N fertilization should be applied no later than 41–50 days after emergence. Deficit irrigation, which received ca.70% of irrigation applied to full irrigation, did not reduce radiation interception and radiation use efficiency.     

Dense planting with less basal nitrogen fertilization might benefit rice cropping for high yield with less environmental impacts

Dense planting and less basal nitrogen (N) fertilization have been recommended to further increase rice (Oryza sativa L.) grain yield and N use efficiency (NUE), respectively. The objective of this study was to evaluate the integrative impacts of dense planting with reduced basal N application (DR) on rice yield, NUE and greenhouse gas (GHG) emissions. Field experiments with one conventional sparse planting (CK) and four treatments of dense planting (increased seedlings per hill) with less basal N application were conducted in northeast China from 2012 to 2013. In addition, a two-factor experiment was conducted to isolate the effect of planting density and basal N rate on CH₄ emission in 2013. Our results show that an increase in planting density by about 50% with a correspondingly reduction in basal N rate by about 30% (DR1 and DR2) enhanced NUE by 14.3–50.6% and rice grain yield by 0.5–7.4% over CK. Meanwhile, DR1 and DR2 reduced GWP by 6.4–12.6% and yield-scaled GWP by 7.0–17.0% over CK. According to the two-factor experiment, soil CH₄ production and oxidation and CH₄ emission were not affected by planting density. However, reduced basal N rate decreased CH₄ emission due to it significantly reduced soil CH₄ production with a smaller reduction in soil CH₄ oxidation. The above results indicate that moderate dense planting with less basal N application might be an environment friendly mode for rice cropping for high yield and NUE with less GHG emissions.