氮磷钾肥对柳树生长的影响研究

针对在柳树生长过程中的施肥效应,对常见肥料品种在柳树上的应用效果进行研究。研究结果表明:氮肥主要促进柳树地上茎杆部分的生长,而磷肥则主要对根部的生长有促进作用,复合肥的显效慢,作用期长,提出在生产中根据不同商业需求合理施用肥料的建议。     

基于白城市酸雨状况下的大气环境分析

利用回归分析的方法对白城市通过2007～2008年酸雨监测数据资料进行统计和研究，得出大气环境的分析和评价，对白城市酸雨现象的发展趋势进行预测。     

Influence of nighttime electrical conductivity of substrate solution on fruit cracking and blossom‐end rot of greenhouse tomato in the tropics

The influence of the electrical conductivity (EC) of the substrate solution during the night, i.e., moderately high EC (“HEC”, 3.0 dS m^–1, full solution) and low EC (“LEC”, 0.5 dS m^–1, CaCl₂ or Ca(NO₃)₂ and H₃BO₃), on the incidences of blossom‐end rot (BER) and fruit cracking (FC) in greenhouse tomato (Solanum lycopersicum L.) was investigated and compared with a control without additional nighttime fertigation (NTF). In three consecutive experiments conducted in Central Thailand between November 2005 and March 2007, additional NTF cycles were applied for 1 h after the regular daytime fertigation (EC 1.5/1.8 dS m^–1, prior to/after the first harvest). In the first experiment (dry season 2005/06), two cultivars with either low (FMTT 260) or high (King Kong 2) susceptibility to BER and FC were used. The total amount of fruits affected by FC or BER was 4‐ and 10‐fold, respectively, higher in King Kong 2, but the relative response to NTF was similar in both cultivars. Therefore, in the following experiments only FMTT 260 was planted. In all experiments, NTF exerted significant effects on the uptake and allocation of water and mineral elements to the fruits and the proportions of fruits affected by BER and FC. The overall proportion of nonmarketable fruits was not significantly reduced, neither through LEC nor HEC because a decrease in BER by LEC and in FC by HEC was counteracted by enhanced FC in LEC and BER in HEC. It is concluded that under the tropical climate conditions of Central Thailand leading to high losses of marketable fruit yield through BER and FC, an integrated approach is required combining an optimized management of the fertigation system and particularly the selection of genotypes highly tolerant of BER and FC.     

融雪时间对川贝母生长的影响

为了探讨融雪时间对川贝母种子、鳞茎及幼苗发芽生长的影响,在青藏高原东部的高山雪场观察了早融、中融、晚融3个不同融雪时间发生部位上川贝母种子和鳞茎的个体重量、种子数量、种子萌发率及幼苗第一片叶的长度,并对不同融雪部位生长的植株进行了比较.结果表明,随着融雪时间的推迟,川贝母的单花种子数和种子重量逐渐增加,和早融部位生长的植株相比,晚融部位生长的植株单花种子数和种子重量分别增加了40.3％和24.6％;但是鳞茎的重量表现出了相反的趋势,和早融部位生长的植株相比,晚融部位生长的植株鳞茎重量降低了22.4％.另外,川贝母的种子大小对幼苗的萌发率没有显著的影响,但对幼苗的第一片叶子长度有明显的影响,和早融部位生长的植株相比,晚融部位生长的植株第一片叶子长度增加了41.6％.说明晚融的积雪有利于川贝母种子产量的提高,而早融的积雪有利于鳞茎的生长.     

Yield Quality Parameters and Chemical Composition of Peanut as Affected by Potassium and Gypsum Applications under Foliar Spraying with Boron

A field experiment was carried out at El-Khattara region (Sharkia Governorate, Egypt) during the 2009 season to study the effect of potassium (K) fertilization, gypsum addition rates, and foliar spraying with boron (B) and combinations of them on growth, yield, yield components, oil quality, and uptake of some macro- and micronutrients by peanut (Arachis hypogaea L. cv. Giza 6) grown on a sandy soil. Biological yield (pod + hay) as well as hay and seed yields were increased significantly as a result of K and gypsum application, but there was no significant increase under foliar spraying with B. The greatest values of 7788, 6585, and 954 kg fed^?1 for biological, hay, and seed yields corresponded to 20.8 kg K fed^?1 + 0.5 ton gypsum fed^?1 without foliar spraying with B. For hay, the greatest value of N uptake was obtained with 20.8 kg K fed^?1 + 1.0 ton gypsum fed^?1, whereas the greatest values for P and K uptake (70.1 and 131 kg fed^?1) were obtained when 20.8 kg K fed^?1 + 0.5 ton gypsum fed^?1 was applied under spraying with B. For seeds, the greatest value of K uptake was obtained when 20.8 kg K fed^?1 + 1.0 ton gypsum fed^?1 was applied, whereas for N and P uptake the greatest values (60.8 and 15.2 kg fed^?1) were obtained when 20.8 kg K fed^?1 + 0.5 ton gypsum fed^?1 were applied under spraying with B. The oil yield of peanut seeds using the Soxhelt extraction method was found to be in the range of 23.1 to 35.2%. The greatest B uptake in hay was obtained without spraying with B, whereas in seeds it was obtained under spraying with B. In both of them was obtained upon application of 20.8 kg K fed^?1 + 0.5 ton gypsum fed^?1. Apparent K recovery (AKR) and K-use efficiency (KUE) were markedly decreased with increasing K addition rates.     

Fluctuations in soil test values for potassium as influenced by time of sampling

Abstract

Soil samples were taken at frequent intervals in 1975 and 1976 from a factorial set of lime ‐K treatments initiated in December 1970 to determine the effect time of sampling has on K soil test values. Previous work at this site had shown wide fluctuations in K soil test values due to sample time thus necessitating a more detailed study than was previously made. Such information is necessary if accurate K fertilizer recommendations are to be made. Samples from 28 unfertilized plots showed that months of sampling significantly affected K soil test values. Soil test values for K were highest in late May and declined as the growing season progressed, remaining low until the relatively higher exchangeable K was re‐established the following spring.

Disregard for this phenomenon could result in inaccurate recommendations for K fertilizer.     

Yield of alfalfa as influenced by levels of P and K fertilization

Abstract

This study was conducted to ascertain further the need for P and K fertilizers to obtain maximum herbage yields from alfalfa (Medicago sativa L.). Vernal alfalfa was established on a low K Piano silt loam (Typic Argiudoll) soil and topdressed with zero, 22.4, and 44.8 kg/ha of P in autumn of seeding year and with zero, 224, and 672 kg/ha of K as KC1 each autumn. The harvest schedule was three cuts annually at first flower; a schedule widely recommended in the North Lake states. No statistical significance was found for P levels nor for the P x K interaction; significance was found only for K levels. Maximum herbage yield was obtained with 224 kg/ha of K in the first harvest year, but with the 672 kg/ha of K rate in the second harvest year. Herbage K and Cl percentages and amounts removed from the soil increased significantly each year with each increase in K applied. Herbage P and N percentages were decreased significantly with the first increment of K. Residual herbage yields showed dramatically the influence of K fertilization on winter survival. All alfalfa stands with no K fertilization were killed completely. Residual yields and stands increased with each increase in K applied. Yield increase over the control was significant only with the second increment of K, while stands increased significantly with each increase in K applied. These data continue to confirm that high levels of soil K are needed for stand survival as well as for high herbage yields.     

Chemistry of soil potassium in Atlantic coastal plain soils: A review

Abstract

Literature dealing with general properties of soil K and with K relationships in Atlantic Coastal Plain Soils was discussed. Potassium, among major and secondary nutrient elements, is the most abundant in soils. It, among mineral cations required by plants, is largest in non‐hydrated size. Potassium has a polarizability equal to .88 ų and a low hydration energy of 34 kcal g^?1 ion^?1. The major K forms in soils are water soluble, exchangeable, nonexchangeable, and mineral. Various dynamic interrelationships exist between these forms with the reaction kinetics between the various phases determining the fate of applied K.

Many Atlantic Coastal Plain soils contain high levels of total K. Most of the total K in these soils is contained in mineral forms such as micas and K‐feldspars. These K forms are slowly released to solution and exchangeable forms that are available to plants. Many researchers have noted a lack of crop response to K fertilization on Atlantic Coastal Plain soils. This lack of response has been ascribed to the high indigenous levels of mineral and non‐exchangeable K in the soils which would become available to crops. Some researchers have also attributed the lack of response to K accumulations in subsoil from leaching of applied K. If the physical and chemical conditions were favorable in the subsoil horizons, e. g., no pan formation and no severe Al toxicity, plant roots could absorb K from the subsoil horizons.     

Preliminary studies on triticale,wheat, barley,and rye responses to lime and N.

Abstract

The lime and N requirements for triticale (X Triticosecale Wittmack) have not been established because of the relatively short history of the crop. This study was designed to evaluate the effects of lime and high N rates on triticale, wheat (Triticum aestivum L.), barley (Hordeum vulgare L.), and rye (Secale cereale L.) on Dickson silt loam (Typic Paleudult) and Decatur silty clay loam (Rhodic Paleudult) in 1974–1976. The soils had pH values of 4.9 and 5.5 with no lime and 5.4 and 5.8, respectively, when limed as recommended. The fertilizer rates were 112, 140, and 170 kg N/ha. Yields and N, P, K, Ca, Mg, Mn, Fe, Al, Zn, Cu, and B were determined in straw and grain. Liming the Dickson soil increased the straw yields of barley at 112 kg N/ha and grain yields of the cultivars generally at the 170 kg N/ha rate. Liming the Decatur soil did not have consistent effects on straw yields but increased the grain yields of the wheat and rye cultivars. Increasing N rate increased the straw yields of wheat on Dickson but decreased the grain yields of barley in the same soil with no lime. Nitrogen fertilization did not have consistent effects on the Decatur soil. The N, P, K, Ca, Mg, and Mn compositions suggested that more differences occured at the species level than at the cultivar level.     

Potassium release by some delaware soils

Abstract

The A and B horizons of 29 Delaware soils were extensively cropped to sudan grass (Sorghum vulgare Pers. Piper) and corn (Zea mays L. Pioneer Brand Hybrid No. 3958) to evaluate the K release characteristics of these soils.

Various chemical analyses were made on these soils. The double acid North Carolina extractant (NCE) was good at predicting K uptake during the early stages of the experiment and was most sensitive with A horizon soils. However, this extractant was not suitable for predicting K uptake in the latter part of the experiment when nonexchangeable K was more important. Boiling IN HNO₃ was a good extractant in the latter part of the experiment when nonexchangeable K was being released and it also predicted K uptake from the B horizon well. Soils leached with 0.025M MgCl₂ and incubated 25 days to determine K released were also highly correlated with plant uptake.