果树施肥十注意

1注意施肥后灌水时间要根据肥料特性而定 施肥后灌水时间的早晚对肥效的影响很大。施肥后有及时灌水和延迟灌水之分。及时灌水的肥料有氨态氮肥和农家肥（人粪尿、骡马粪、猪粪、饼肥等）。氨水和碳酸氢铵是速效氮肥,极易挥发,因此,氨水和碳酸氢铵必须沟施覆土并及时浇水。硫酸铵和氯化铵易被作物吸收,施用后灌水使肥料与土壤密接,能尽快发挥肥效。农家肥含有大量的微生物,这些微生物必须在充足水分的条件下繁殖、分解有机质而释放大量的养分。因此,施用农家肥后也要及时浇水。而施用尿素却要延迟灌水。因尿素中酰胺态氮不能被果树利用,须在尿酶的作用下转化为碳酸氢铵后才能被吸收,如果浇水过早,酰胺态氮易随水流失而浪费。所以,施尿素后应延迟5—7d浇水。     

滴灌模式下灌水量对酿酒葡萄生长及果实品质的影响

为确定滴灌条件下适合酿酒葡萄的灌水量以及进一步认识灌水量与葡萄生长、果实品质和产量之间的关系,以酿酒葡萄"马瑟兰"为材料,开展田间小区灌水试验,分别设置T1:4 500 m^3/hm^2、T2:3 600 m^3/hm^2、T3:2 700 m^3/hm^2和T4:1 800 m^3/hm^2 4个灌水量,研究不同灌水量对酿酒葡萄生长发育、品质及产量的影响。结果表明:滴灌条件下,灌水量对酿酒葡萄新梢生长、果实品质及产量影响显著。随着灌水量的减少,酿酒葡萄新梢生长、果实外观品质、果皮酚类物质含量以及产量因子指标呈现先升高后降低的趋势,而果实可溶性固形物含量、还原糖含量和糖酸比逐渐增加,可滴定酸含量逐渐减少。T2处理条件下,果实外观品质好,内在品质较优,果皮酚类物质含量高,产量高。灌水量为3 600 m^3/hm^2是较适宜灌水量。     

科学优化核桃栽植密度的成功实践

正近年来,皮山县按照自治区提升林果综合生产能力的总要求,结合实际,对产量品质下降、林牧农发展不能协调的过密核桃林进行隔行、隔株大树移栽。移植后核桃园通风透光条件明显改善,第2年可恢复产量,果品品质明显提高,移栽成活率达90%以上,为实     

沙棘嫩枝扦插生根苗移植和管理技术

沙棘嫩枝扦插生根苗移植的圃地应选择地势平坦,排水良好,土层深厚的沙壤土;移栽后每年追肥2次,每次每平方米追10 g硝酸铵效果最好;移栽后立即灌水,做好松土保墒和除草工作。新梢生长量当年可达35.5cm,地径0.60 cm,根数(≥0.1)为6.3条。新梢生长量和地径分别比对照提高了6.9%和9.1%,根数比对照多1.6条。     

不同播期对红土晒烟品质的影响

2004～2005年冬春季在保山怒江坝进行红土晒烟不同播种期的试验,结果表明:红土晒烟肯那品种的最佳播种期为10月下旬,最佳的移栽期在次年1月上旬,该播期栽的烟苗,田间长势整齐,烟丝品质好,经济效益高,调制期间降雨量少,随着移栽的提前或推迟,烟丝的品质和经济指标降低。     

葡萄一年应灌几次水

1　催芽水在葡萄萌芽前结合施肥灌水,使树体有着良好的营养状况,对萌芽以及花芽的进一步分化有着重要作用,灌水量视土壤墒情而定,以湿润50cm以上土层为宜。2　催花水从萌芽到开花需灌水1～2次,最后1次灌水在开花前10d左右,以满足新梢和花序生长的需要,为开花座果创造良好的肥水条件。开花期一般不浇水,以免加重落花落果。3　催果水在座果后到浆果硬核末期前需多次灌水(结合施肥),以增加副梢叶量,防止新梢过早停长,使座住的果迅速膨大。但在浆果上色到成熟期,为了提高浆果品质,增加果实的色、香、味,抑制营养生长,促进枝条成熟,此期应控制灌…     

云杉苗期最适施氮量的试验研究

对云杉新播和换床苗的不同施氮量、不同施氮次数、不同施氮时间等因素与苗木生长的相关关系进行了研究,结果表明：尿素最佳施肥量新播苗为10 g/m^2,换床苗为24 g/m^2;以2次施氮为好;新播苗2次施氮最佳时期：第1次为6月上旬,第2次为6月下旬;换床苗2次最佳施氮时期：第1次为5月中下旬,第2次为6月上旬至下旬。     

灌水和施肥对促进板栗产量和生长量的影响

以9年生‘云栗15’板栗为试验材料,采用正交设计,研究了灌水量、灌水次数、追施N肥、追施K肥4个因子,各因子3个不同水平经营管理措施对板栗产量和干周增长量的影响。结果表明:灌溉次数和次灌水量是影响板栗产量的关键因子,而其中灌溉次数尤为重要;灌水量和补充施氮量是影响干周增长量的关键因子。从综合评比看,次灌水量在975 m~3/hm~2,灌溉次数在3次的组合均能得到较高的板栗产量。因此,在较好的立地条件下,灌水较施肥对板栗产量有较大的促进作用,是保证板栗产量和树体生长的重要条件。     

油茶芽苗砧嫁接苗田间移栽试验

以怀化市林业科学研究所油茶采穗圃的湘林1号、104号和长林3号、4号等20多个油茶优良无性系为试材,对油茶芽苗砧嫁接苗进行田间移栽试验。试验结果表明:短期移栽密度以222~333株/m2,株行距3 cm×15 cm、3 cm×12 cm和3 cm×10 cm,产苗量7~10万株/667 m2的密度最合适;移栽天气以毛毛细雨天和阴天最佳,其次是晴天;最适砧木粗度为0.31~0.45 cm;拱膜密封嫁接苗保温保湿天数以90~95 d,且第1次密封时间以40 d左右为好。     

无籽刺梨试管苗移栽及其影响因素的探讨

系统研究无籽刺梨试管苗的移栽过程,探讨移栽基质、光照强度、移栽时间、施肥因素对其移栽及其生长的影响。无籽刺梨试管苗移栽最佳基质为腐质土+珍珠岩(2?1),移栽最佳时期为3～4月,遮光50%,在幼苗生长期每隔7d喷1次1/4MS营养液,移栽成活率可达90%以上。     

Relative importance of water and nutrients on the growth of coast Douglas fir in the Pacific Northwest

The Douglas-fir region in northwestern North America is characterized by abundant moisture supply during winter, extended dry periods during the growing-season and significant differences in water availability. Many soils have low fertility and native tree species respond to nitrogen fertilization, especially Pseudotsuga menziesii (Mirb.) Franco (coast Douglas fir). Although irrigation of commercial forests in this region is currently impractical, questions arising about the relative importance of water and nutrients were examined using long-term growth data from three studies.

At Pack Forest, fertilization within irrigation doubled growth rates, and no positie growth responses were measured from irrigation. Short-term (5 years) irrigation with sewage effluent containing many nutrients resulted in a six-fold increase in biomass production for poplar and three-fold for Douglas fir as compared to irrigation with equal volumes of river water.

Volume growth in 12- to 65-year-old stands in southwestern Oregon was increased by fertilization at about 70% of the location; annual gain averaged 2.73 m³ ha⁻¹ for 5–12 years. Response was not related to annual precipitation, which ranhed from 81 to 279 cm, nor other moisture-related variables. Absolute and relative volume response showed highest correlation with soil carbon: nitrogen ratio.

Compared with nutrition, moisture does not seem to be a major limiting factor for growth in the Douglas-fir region of the Pacific northwest.     

不同水分管理措施对抽梢期油茶树体养分含量的影响

为探讨不同水分管理对抽梢期油茶树体养分状况的影响,从而为油茶水分管理提供科学依据。以‘长林4号’5年生油茶为试材,设置滴灌+花生秆+稻草、滴灌+生态膜、滴灌+油茶壳、滴灌、滴灌+黑地膜、花生秆+稻草、生态膜、油茶壳、黑地膜、不覆盖不灌水(CK)共10种水分管理措施,测定不同水分管理措施下抽梢期树体各器官氮、磷、钾养分含量,并对各养分分布特征进行了分析。结果表明:不同水分管理措施对抽梢期油茶老叶和根N、P、K含量、新叶P、K含量以及枝条P养分含量影响差异显著。不同水分管理措施对抽梢期老叶、根养分含量具有明显促进作用,对当年生新叶和枝条的影响比较小。滴灌+花生秆+稻草处理和滴灌+黑地膜处理更有利于养分的积累,滴灌+花生秆+稻草处理是最经济最环保的水分管理措施。     

不同毛白杨无性系林分蓄积量的长期水氮耦合效应

【目的】研究不同田间持水量和纯氮施用量对毛白杨人工林单位面积上林分蓄积量的影响,确定毛白杨无性系最佳水氮组合方案。【方法】采用裂区试验设计在河北威县林地研究不同水氮耦合处理对不同无性系(BT17,B331,S86,1316)毛白杨林分蓄积量影响。【结果】1)无性系在不同纯氮施用量和田间持水量灌溉条件下单位面积上林分生长量有差异,S86无性系对高水肥处理响应较好,1316无性系响应较差。2)对杨树人工林进行水分灌溉管理措施时,应该设置田间持水量75%以上作为灌溉临界值同时灌溉临界值应考虑造林地区的环境条件、造林密度、林龄等因素。3)杨树人工林单位面积上纯氮施肥量范围是在100~400kg·hm^-2,且施肥量应当根据实验地区肥力等级状况进行酌量加减。【结论】在河北威县S86无性系是在田间持水量75%以上和每株施氮量160g的管理措施下能实现速生丰产的毛白杨无性系,建议在相近地区进行杨树人工林速生丰产林培育时候优先考虑。     

Effects of timing of nitrogen fertilization on shoot development in peach (Prunus persica) trees

Shoot development was studied for two consecutive years in peach trees fertilized with N either in the previous fall or in the middle of the growing season. During the first year, two additional treatments were studied: no N supply and nitrate supplied in the irrigation water throughout the growing season. The number of shoots that developed depended on nitrogen availability in the period following bud break. During shoot development, leaf emergence occurred in one, two, or three stages, which ended at about 500 to 600 degree days, 1,000 to 1,200 degree days, and 1,500 to 2,000 degree days after bloom, respectively. The proportion of shoots exhibiting a second or third developmental stage depended on nitrogen availability at the beginning of that stage. Increasing nitrogen availability during a developmental stage prolonged the stage and increased the number of leaves produced.     

Effects of Irrigation and Fertilization on Soil Microbial Biomass and Functional Diversity

Abstract

Optimal water and nutrient treatment effects on soil mi-crobial characteristics, including microbial functional diversity and mi-crobial biomass carbon (C) and nitrogen (N) were assessed at a loblolly pine plantation on a Sandhills site after 6 years of continuous fertilization and irrigation. Fertilization significantly increased soil C and N and microbial C and N. Irrigation significantly increased soil C and N, and microbial C. Fertilization, irrigation, and their interaction changed soil microbial selection of carbon compounds, but did not influence the numbers of carbon compounds utilized by soil microbes, as measured by the BIOLOG method suggesting that soil microbial species may have changed. The increases in soil microbial biomass and soil C and N indicate that the fertilization and irrigation treatments have had a positive effect on soil productivity on this very sandy site.     

Nutrient use and uptake in Pinus taeda

We quantified nitrogen (N), phosphorus (P), potassium (K), calcium (Ca) and magnesium (Mg) content, use (nutrient amount for one growth year), retranslocation (nutrients recycled before foliage senescence), uptake (use minus retranslocation), volume production per unit of uptake and fertilizer-uptake efficiency (percent applied taken up) in a 2 x 2 (nutrient and water) factorial experiment replicated four times in an 8-year-old loblolly pine (Pinus taeda L.) stand growing on a nutrient-poor sandy soil in Scotland County, North Carolina, USA. Over 14 years, we applied 1140, 168, 393, 168 and 146 kg ha(-1) of elemental N, P, K, Ca and Mg fertilizer, respectively, and an average of 710 mm year(-1) of irrigation. All plots received complete vegetation control. Fertilization about doubled tissue N, P, K and Mg contents at age 21, whereas irrigation resulted in smaller increases in nutrient contents. Maximum annual uptake was 101, 9.3, 44, 37 and 13 kg ha(-1) year(-1) and volume production per unit of nutrient uptake was 0.35, 3.5, 0.66, 1.1 and 3.1 m(3) kg(-1), for N, P, K, Ca and Mg, respectively. Irrigated plots had greater volume production per unit of N, P, K and Mg uptake than control plots, likely because irrigation allowed photosynthesis to continue during dry periods. Fertilized plus irrigated plots had less volume production per unit of these elements than the fertilized plots either because nutrient uptake exceeded the requirement for optimum growth or because available water (rainfall plus irrigation) was insufficient for the leaf area achieved with fertilization. At age 19, fertilizer-uptake efficiencies for N, P, K, Ca and Mg were 53, 24, 62, 57 and 39%, respectively, and increased with irrigation to 68, 36, 78, 116 and 55%, respectively. The scale of fertilizer uptake was likely a result of low native site nutrient availability, study longevity, measurement of all tissue components on site, a comprehensive assessment of coarse roots, and the 3-m rooting depth. Ecosystem nitrogen retention (applied nitrogen found in living plant material, litter fall and soil to 150-cm depth) was estimated at 79% at age 17, a value that would likely be greater when including soil nitrogen to rooting depth and calculating retention at age 21 when the study ended. The ecosystem retention value provides evidence that intensive site resource management can be accomplished with low likelihood of applied materials moving offsite.     

水肥耦合对杨树根区水、氮运移及吸收的影响研究进展

随着我国木材需求量不断增加,速生丰产林提质增产迫在眉睫,急需探求合理高效的水肥集约经营策略。文中对灌溉施肥条件下植物根区水和氮（N）运移分布、吸收根形态与分布,以及水和N吸收相关研究进行综述,结论如下:1）水、N分布与施肥灌水量、土壤质地、降水、地下水位等条件有关。主要研究方法有室内、大田试验以及数值模拟法。由不同时刻水、N运移分布情况发现,改善水肥耦合措施,可降低N淋失对地下水的污染,同时提高植物的水、N利用效率。2）杨树吸收根主要分布于土壤表层,呈“倒金字塔”型分布,随远离树干方向,分布趋于浅层化,垂直根呈“S”形,整体表现为“二态性”;从根系分布规律发现,少量多次随水施肥有利于吸收根及林分生长。3）杨树品种、生育阶段、施肥水平以及土壤条件等不同,其水、N吸收情况及后期分配均存在差异。但恰当的水肥比例和灌施频率均有利于水、N吸收。以往研究只关注根区水和N运移、根系分布、吸收利用过程中的某一环节,而对各环节间动态联系以及整体调控机制知之甚少。因此,应设置不同水、N耦合方式,对各环节进行关联分析,明确调控机制,以期实现水、N效率最大化,有效提升林木产量。     

Effects of acid rain treatments on the birch rust,Melampsoridium betulinum and birch,Betula pendula

Effects of acidic rain on birch rust and on the growth of Betula pendula seedlings were studied by irrigating with acidic water at pH 3, 4 and 5.6. The seedlings were inoculated with uredospores of Melampsoridium betulinum and the development of rust and the severity of rust infection was examined. The increasing acidity of the irrigation water did not affect on the development of the rust, but the nitrogen in the acidified water resulted in an extension of seedling growth, and hence the leaves became senescent at a later date in autumn and the rust grew for a longer time.     

Variation analysis of growth traits of four poplar clones under different water and fertilizer management

To determine appropriate quantities of water and fertilizer required for early growth of hybrid poplar cuttings,we recorded the growth traits of four clones grown under four factors(irrigation and nitrogen,phosphorus,and potassium fertilizers),each with four levels,using an orthogonal experimental design.A logistic model was used to estimate growth in height.The growth curves for tree height were sigmoid,and the model R^2 values were greater than 0.9,which indicated that the fit was highly significant.ANOVA results for tree height and basal diameter indicated that all sources of variance showed significant differences(p<0.001).The average tree height and basal diameter for all the four clones under the different treatments ranged from 155.39 to 235.04 cm,and from 13.71 to 17.42 mm,respectively.A highly positive correlation between the extreme k value and tree height was observed,suggesting that the k value was an accurate estimation of tree height.For model parameters,the earliest average time point for the onset of the rapid growth period of poplar clones was 131 d,and the highest average increment in tree height during the rapid growth period was 138.78 cm.The highest average tree height for all clones under each factor was 219,210.51,200,and 201 cm when treated with either 1200 mL of water applied every third day,3 g of nitrogen,0 g of phosphorus,or 0 g of potassium,respectively.The most suitable treatment for the early growth of hybrid poplar cuttings,as suggested by the developed logistic model,was 1200 mL of water applied every third day and three applications of 1 g nitrogen(in the form of CH4N2O).     

Nitrogen transformations and soil processes in a wastewater-irrigated,mature Appalachian hardwood forest

Wastewater bioremediation has been practised successfully in several forests without significant adverse effect on water quality of adjacent aquatic systems. However, long-term success of wastewater irrigation systems depends on an overall positive response of the forest ecosystem to substantial amounts of added water and nutrients over time. Municipal wastewater irrigation effects on the fate of added nitrogen in a mature Appalachian hardwood forest were investigated during the first 2 years of irrigation. Wastewater was secondarily treated, chlorinated, and sprayed on the study site at five rates. Forest litter N decreased on irrigated sites due to increased litter decomposition rates. Nitrogen mineralization potential (N₀) decreased greatly in soils irrigated at a rate of 140 cm year⁻¹ for 2 years. Net nitrification and relative nitrification (the amount of NO₃⁻-N as a proportion of the total mineral N) increased proportionally with irrigation rate. The highest irrigation rates increased denitrification activity and contributed significantly to the bioremediation process by removing nitrate that otherwise would have been subject to leaching. The increase in NO₃⁻ production in the soil and limited N sequestration by the forest system nevertheless resulted in a net loss of N via leaching. Nitrate concentrations of soil water increased owing to irrigation, with the highest rate at 11 mg 1⁻¹ on sites receiving 70 cm year⁻¹. During the 2-year period, the forest ecosystem experienced a net leaching loss of N that ranged from 14.8 to 105 kg N ha⁻¹ year⁻¹, depending on the application rate. It is likely that this mature hardwood forest will continue to lose N, and that little or no additional N will be sequestered.