Nutritional Environment of Tropical Peat Soils in Sarawak,Malaysia Based on Soil Solution Composition

It has been considered that natural peat soils and swamp forest ecosystems in the tropics are quite oligotrophic. This concept seems to be related to the low mineral contents in the soil solid phase of the peat soils. However, some nutritional elements such as K, Mg, Ca, and/or P may be abundant in the soil solution phase and could easily migrate in peat soils. In order to analyze the nutritional environment of peat soils, chemical composition of the soil solid phase and soil solution was compared.

This study was carried out in Naman Forest Reserve, Sibu and in/around Sg. Talau Peat Research Station, Mukah, Sarawak, Malaysia. In both areas, each of the three study sites with a different depth of underlying mineral layer was selected for sampling of soil and soil solution. All the soils studied except for one shallow peat profile were classified into Oligotrophic peat based on Fleischer’s criteria. The soil solution collected monthly showed the following characteristics in its composition.

1. Concentrations of Al, Si, and Fe were higher in the soil solution from the shallow peat than in that from the deep peat, reflecting the effect of underlying mineral layers on the soil solution composition.

2. Concentrations of Na, Mg, and Cl in the soil solution and Na and Mg contents in the soil solid phase reflected the distance from the sea. In the Naman series, accumulation of K and Ca in the soil solution was larger in the surface layer in the deep peat than in the shallow peat, though such clear trend was not observed for the K content in the soil solid phase.

3. The concentrations of N and P were fairly high in the soil solution in all the profiles except for P in the profile near the center of the peat dome. Dissolved P consisted mostly of ortho-phosphate, whereas a larger part of N was in the organic form.

4. At the Sago plantation farm on deep peat, depletion of K and P was observed during the rainy season. Such instability in the concentrations in the soil solution was attributed to forest clear-cutting and subsequent disturbance of nutrient cycling.

In general, the concentrations of N, P, K, and Ca in the soil solution were not low even in the Oligotrophic peat. However, in taking account of the fact that the peat soils showed low mineral contents in the available forms and that the bulk density was also quite low, the potential capacity to supply K, Ca, and/ or P was not necessarily high in spite of the apparent high intensity observed for the soil solution composition. Therefore, from the viewpoint of nutrient dynamics, the potential for the use of reclaimed peat land was considered to be rather limited especially under low input management.     

Phosphorus Fertilizer use in Pineapple Cultivation with in situ Residues Burning on Organic Soils

Abstract

In Malaysia, pineapples are grown on peat soils, but most phosphorus (P) fertilizer recommendations are made without due quantification of P uptake; the distribution of P in roots, stem, leaves, peduncle, fruit, and crown; or loss through leaching even though P retention in peat soils is low. This study was conducted to determine applied P‐use efficiency under a conventionally recommended fertilization regime in pineapple cultivation with in situ residues burning before replanting. Results showed that most of the P uptake in pineapple can be found in the fruit, stem, leaves, and crown, but the general trend of P distribution was in the order of fruits>leaves>stem>crown>peduncle>roots. Phosphorus recovery in pineapple cultivation was about 40%, and this low recovery was attributed to leaching. Hence, fertilizer recommendations need to take into consideration P loss through leaching. This will help to increase P‐use efficiency because it is not possible to build up P content of peat soils. As a result, the need to assess the possibility of side‐dress applications of phosphatic fertilizers on peat soil is necessary.     

Influence of Biomass Partitioning and Nutrient Uptake on Yield of Arecanut Grown on a Laterite Soil

The present investigation was conducted on a laterite soil to study biomass partitioning and nutrient-uptake pattern in the aboveground parts of arecanut palm and their relationships to yield. Total biomass production was significantly greater in high-yielding plants (43.6 kg palm^?1) than in low-yielding plants (30.8 kg palm^?1). Total standing biomass of trunk accounted for 69–74% of the total aboveground biomass in arecanut palm. Dry-matter partitioning to kernel was only 4–10% of the total biomass. The uptake of major nutrients varied significantly between low- and high-yielding plants. Calcium (Ca) uptake was greater by trunk than by other parts, while magnesium (Mg) accumulation was similar in trunk and leaf. The uptake of micronutrients by aboveground parts except leaf was significantly different between low- and high-yielding plants. The present study indicated that combined effect of greater biomass production and nutrient uptake had direct impact on marketable yield of arecanut.     

Using Thermal Sensitivity Analysis to Determine the Impact of Drainage on the Hydrochemistry of a Tropical Peat Soil from Malaysia

Peat from an area of pristine swamp in Malaysia and from an area of that swamp drained 10 years earlier for agriculture was incubated along a temperature gradient from 0 to 20 °C to simulate microbial activity through changes in temperature. With increasing temperature, nitrate availability decreased in the pristine peat but increased in the drained peat, suggesting that drainage has altered the principle nitrate transformation process from denitrification to nitrification. Sulfate concentrations in the pristine peat exhibited a greater proportional decrease with increasing temperature than in the drained peat, suggesting that drainage has decreased the influence of sulfate reduction over sulfate availability at this site. With the exception of phosphate, nutrient concentrations in the drained site were significantly greater (P < 0.05) than in the pristine site. Biogeochemical models should consider that drained peatlands may respond very differently to the temperature change predicted by current climate change models.     

Establishment of Critical Sap and Soil Nitrate Concentrations using a Cardy Nitrate Meter for Two Carrot Cultivars Grown on Organic and Mineral Soil

Abstract

Nitrate (NO₃ ^?) meters have been used effectively for crop nitrogen (N) management in many crops, including corn and cabbage. The use of a Cardy NO₃ ^? meter to assess the N status of the carrot crop could improve the utilization of applied N, but critical NO₃‐N concentrations are required. Two carrot cultivars were grown on mineral and organic soils over 3 years at five N application rates to establish critical sap and soil NO₃‐N concentrations and to identify the effects of soil type and cultivar. Although a yield response to N application occurred on mineral soil in 2 of 3 years, consistent critical sap NO₃‐N concentrations could not be established because of variability among years, cultivars, and soil types. Critical soil nitrate concentrations were highly variable, but values of 31 to 36 mg · L^?1 NO₃‐N could be established for the early sampling date to 30 cm deep. Sap NO₃‐N concentrations cannot be used alone for N analysis of carrots, but early‐season soil NO₃‐N assessment could be useful in adjusting N‐fertilization practices.     

Growth,Oil Yield,and Ion Partitioning in Basil Grown on Sodic Soils

Abstract

A field experiment was conducted on sodic soil during its rainy seasons of 2004 and 2005 to evaluate five germplasms of Ocimum basilicum (viz. CSLT 5, CSLT 9, CSLT‐12, CSLT‐12‐1, and CSLT‐13) for their growth performance, their oil yield, chemical constituents of their oil, and ion‐partitioning characteristics in different parts of the plants. The highest shoot yield was recorded in CSLT‐12, followed by CSLT‐9 and CSLT‐13. The highest oil yield was recorded in CSLT‐13, followed by CSLT‐12‐1. This indicated that a high herbage yield does not always result in a high oil yield. Germplasm CSLT‐12 and CSLT‐12‐1 seemed to have better adaptation in sodic soil then other germplasms on the basis of root architecture and root density. Germplasm CSLT‐5 was of the linalool chemotype, yielding 62.36% linalool in oil, whereas CSLT‐13 and CSLT‐9 were methyl chavicol chemotypes, yielding 69.59% and 56.98% of methyl chavicol, respectively. Germplasms CSLT 12 and CSLT 12‐1 are intermediate types that yielded 48.86% of methyl chavicol and 43.37% of linalool. The root, stem (main branch), and laterals (primary branches) were better sodium (Na)+accumulators then leaves and inflorescences. On the other hand, leaves were better chloride (Cl^?) accumulators than roots. A higher K⁺/Na⁺ ratio was found in the immature leaves than in the matured leaves.     

神农架大九湖亚高山典型泥炭湿地土壤养分特征分析

基于湖北省神农架国家公园大九湖亚高山典型泥炭湿地土壤总有机碳、总氮、总磷、铵态氮、有效磷、速效钾养分含量进行时间(春、夏、秋、冬)和空间(表层15 cm、中层30 cm、底层45 cm)特征分析。结果表明:(1)该区域土壤各样分以及pH、Eh、容重均满足正态分布,其中有效磷、速效钾为中强变异性,均值为31.33,71.2 mg/kg,总有机碳、总磷、铵态氮、pH、Eh、容重为中弱变异性,均值为419.2,1.56 g/kg和67.57 mg/kg, 5.33,104.4,0.155 g/kg,总氮为弱变异性,均值为20.13 g/kg。(2)土壤总有机碳在季节以及深度变化上均不存在显著差异,总氮与总磷在首层与其余2层存在显著差异,在季节上总氮在首层存在季节差异,总磷在首、中层存在显著差异,土壤养分仅速效钾与首层和其余2层存在显著差异。(3)土壤有机碳、总磷、铵态氮与总氮、速效钾、总磷与铵态氮呈显著正相关,总有机碳与土壤容重、有效磷与Eh,pH与Eh呈显著负相关。(4)研究区土壤总有机碳与总氮较高于我国其余泥炭湿地,随着纬度升高土壤有机碳含量呈现降低的趋势。     

Kinetic Parameters of Gross N Mineralization of Peat Soils as Related to the Composition of Soil Organic Matter

Peat land has been considered as an alternative type of land for agricultural development especially in the tropics. In the present study, the N-supplying capacity, one of the most important soil properties in terms of crop production, of peat soils was examined. Ten peat soil samples were collected from Indonesia, Malaysia, and Japan. Gross N mineralization in the soil samples was estimated using a zero-order model, and kinetic parameters of mineralization were determined using a simple type model. Soil organic matter composition was investigated using ¹³C CPMAS NMR. Mineralization potential ( N ₀), apparent activation energy ( E _a), and mineralization rate constant ( k ) ranged between 571–2,445 mg kg⁻¹, 281–8,181 J mol⁻¹, and 0.009–0.020 d⁻¹, respectively. Although none of the parameters showed a significant correlation with the soil C/N ratio, a negative correlation was observed between the k value and the ratio of the proportion of alkyl C in total C to that of O -alkyl C estimated by ¹³C CPMAS NMR. The latter suggested that the k values were higher in the peat soils relatively rich in readily decomposable organic matter including carbohydrates.     

Influence of Nitrogen and Saline Water on the Growth and Partitioning of Mineral Content in Maize

ABSTRACT

Saline irrigation water has a tremendous impact on the yield potential of crops. Distribution of mineral elements in the parts of maize plant in response to saline water and nitrogen (N) nutrition was studied in a pot experiment for six weeks. Plants were irrigated either with tap water or saline water (ECw: 3.2 dSm^?1). Nitrogen was applied at the rate of 0, 50, 100 and 200-kg ha^?1 denoted as N0, N1, N2, and N3, respectively. Plants were separated into leaf, stem and root and analyzed for N, calcium (Ca), magnesium (Mg), sodium (Na), and potassium (K) concentrations. Dry matter production of leaf, stem and root was significantly reduced with saline water. The partitioning of elements in plants was the function of nitrogen and saline water. The N concentration of plant parts varied in the order of leaf > stem > root. A significant decrease in the N content was noted in plants under saline water. The root contained the highest Na content, Ca and Mg were higher in the leaf, whereas K was highest in the stem under saline water. Sodium was highest in the root and the remainder elements were greatest in the stem under tap water. Potassium and Cl were significantly reduced by N level whereas the reverse was true for Ca, Mg and Na content. The Na/K, Na/Ca, and Na/Mg ratios were also higher in salt stressed plant parts due to higher accumulation of Na ion. Among N-fertilizer treatments the Na/Ca and Na/Mg ratios were highest in control whereas Na/K increased with the addition of N. This study indicated that interaction of saline water and nitrogen has mixed effects on the partitioning of mineral elements in maize.     

Sugarcane Biomass Yield Response to Phosphorus Fertilizer on Four Mineral Soils as Related to Extractable Soil Phosphorus

ABSTRACT

The efficient use of phosphorus (P) fertilizers is very important in South Florida so that the environmental impact is minimal while meeting crop demand. To ensure that this is accomplished, an updated soil test P calibration is needed for sugarcane (Saccharum spp.) grown on Florida mineral soils, which accounts for almost 30% of the total sugarcane planted in the state. An outdoor pot experiment was conducted with the objective of evaluating four soil extractants for potential use in soil test P calibrations. Sugarcane cultivar CL 88–4730 was grown in 26L pots in a randomized complete block design with four replications of four P fertilizer rates (0, 38, 76, and 152 mg P L^?1 soil) and four soil series (2 Spodosols, 1 Entisol, and 1 Alfisol). Sugarcane biomass was significantly increased with P fertilizer application and extractable soil P significantly increased with increasing P fertilizer rate. Strongest relationships of extractable soil P with relative fresh weight yield were determined with the water, acetic acid, and ammonium acetate extractants. All extractants tested, including Mehlich 3, had significant relationships with relative yield and leaf P concentration and so all these extractants should be considered in further field calibration studies with sugarcane on Florida mineral soils.

Abbreviations: EAA: Everglades Agricultural Area; EREC: Everglades Research and Education Center; OM: organic matter; TSP: Triple superphosphate     

水肥一体化技术对辣椒干物质积累及养分吸收规律的影响

[目的]针对目前设施蔬菜生产中存在的水肥利用率低等问题,研究水肥一体化技术对日光温室辣椒干物质积累及养分吸收规律的影响,为甘肃省设施辣椒的可持续发展生产提供科学依据。[方法]通过田间试验,以常规沟灌冲施肥为对照(T1),研究水肥一体化技术处理(T2)对日光温室辣椒"陇椒3号"干物质积累及养分吸收规律的影响。[结果](1)水肥一体化技术能显著促进了辣椒植株干物质的积累,T2处理干物质积累总量比T1提高了9.21%,果实和根干物质积累分别提高了22.47%和7.29%;提前30d到达干物重第一个平衡期,推迟41d到达第2个平衡期。(2)T2处理N,P2O5,K2O吸收积累总量比T1增加了18.23%,30.73%和19.76%;T2处理果实中N所占比例比T1处理提高了9.73%;P2O5提高了13.70%;K2O提高了13.00%。(3)T2处理比T1氮磷钾利用率分别提高了51.0%;43.3%和71.2%;节水48.9%;增产22.1%;增收3.55万元/hm2。[结论]水肥一体化技术能提高辣椒的干物质和养分积累量,提高果实中的分配比例。     

不同施肥模式对稻田土壤速效养分含量及水稻产量的影响

为了综合评价中国南方稻田不同施肥模式对土壤速效养分及水稻产量的影响,并找到最佳施肥模式,本试验在浏阳市北盛镇、荷花镇和达浒镇3个不同基础地力水稻田块从2013年起进行田间定位试验,比较不施肥、常规施肥、60%化肥+40%有机肥(秸秆+紫云英)和单纯施用化肥处理的水稻产量和土壤速效养分含量变化。3年定位试验表明:不同施肥模式相比无肥处理均能显著提高水稻生物产量,以60%化肥+40%有机肥处理最为显著,且生物产量表现出逐年递增的趋势。通过提高水稻有效穗数和穗粒数使水稻产量显著高于其他处理,60%化肥+40%有机肥处理相比不施肥、纯化肥、常规施肥处理分别增产38.3%~62.4%、1.7%~9.6%、8.4%~12.0%。土壤中速效养分含量表现出60%化肥+40%有机肥处理显著高于其他处理的规律,且速效养分含量逐年递增,而纯化肥处理速效养分逐年递减。从当季作物产量而言,低肥区应加大化肥在有机无机配施中的比例,但从长远培肥地力方面,应适当加大有机肥在配施中所占比例,对于中高肥区则可逐步增加有机肥施用比例。不施肥会降低土壤肥力,而施肥具有明显培肥地力的效果,60%化肥+40%有机肥的施肥模式培肥地力效果最为显著,有利于增加水稻有效穗数和穗粒数,产量显著高于其他处理。     

木本泥炭对红黄壤性水田土壤有机质提升和细菌群落组成的影响

通过工程措施开发新垦耕地是增加耕地面积的重要方法,这些新垦耕地的主要问题为土壤有机质(SOM)低下,而农田SOM培育是一个漫长的过程。本研究以新垦红黄壤性水田为研究对象,通过施用腐熟秸秆及与土壤腐殖质结构类似的木本泥炭,明确其快速提升SOM效应。此外,为了促进秸秆养分的快速转化,本研究进一步比较分析了3种商用激发剂的激发秸秆分解潜力,并采用16s高通量测序技术阐明其微生物机制。试验包含6个处理:对照(CK)、施用腐熟秸秆(S)、施用腐熟秸秆+木本泥炭(SP)、以及在SP基础上添加激发剂Ⅰ、Ⅱ、Ⅲ(SPJ1、SPJ2、SPJ3)。结果表明,SP、SPJ1、SPJ2、SPJ3中的土壤有机质(SOM)、易氧化碳(EOC)、可溶性有机碳(DOC)分别比S或CK处理高12.1%～20.6%、29.9%～48.9%、50.8%～75.5%,微生物生物量碳(MBC)则为它们的10.5倍～16.1倍,导致MBC/MBN增加了5.1倍～12.4倍;土壤有效磷(Ava P)和团聚度在SPJ1、SPJ2、SPJ3间类似,并比SP、S、CK处理显著提高44.7%～63.6%、26.4%～43.6%,表明木本泥...     

Influence of Aluminum on the Growth and Organic Acid Exudation in Alfalfa Cultivars Grown in Nutrient Solution

A study was conducted to evaluate the effects of aluminum (Al) in nutrient solutions on the dry weight (DW) yield, Al and phosphorus (P) contents, and organic acid exudation in alfalfa (Medicago sativa L.). Four alfalfa cultivars (‘Robust’, ‘Sceptre’, ‘Aquarius’, and ‘California-55’) were grown in nutrient solution at pH 4.5 and 6.0, with (50 and 100 μM) and without Al. The results revealed that Al caused a significant reduction in DW, especially in pH 4.5 treatment. Organic acid exudation was affected by pH and Al treatments. Citrate and succinate exudation increased with the high Al treatment at pH 4.5. However, no relationship between pH and carboxylate exudation was observed at pH 6.0. Accumulation of P and Al in roots suggests the existence of an exclusion mechanism for Al in alfalfa. Selection of cultivars with enhanced organic exudation capacity in response to Al might be useful for alfalfa production in moderately acidic soils.     

A Comparative Study of the Use of Organic Carbon and Loss on Ignition in Defining Tropical Organic Soil Materials

Organic soils or Histosols or peats as they are commonly referred to, are characterized by the presence of large amounts of organic soil materials (OSM), which is commonly quantified by the Walkley and Black (1934) (WB) method to determine the soil organic matter (SOM) using a correction factor of 1.724. SOM of Histosols is also identified through a combustion (loss on ignition, LOI) or elemental C-analysis (with a carbon-nitrogen-sulfur (CNS) analyzer with combustion and gas density detector). These methods were established using temperate and boreal peat deposits and here we demonstrate that tropical peat deposits require a modified approach. Typical SE-Asian tropical lowland peat pedons from rain forest and oil palm settings were sampled and the material analysed using a CNS analyzer, WB-C and LOI. The ratios for LOI:CNS-C for the 20 samples yielded values between 2.00–3.09 with a mean of 2.50 while the LOI:WB-C ratio yielded values from 1.75 to 2.58 with a mean of 1.94. A comparison of these values for topsoils and subsoils showed mean ratios (LOI:WB-C) of 1.94 and 1.89 for topsoils and subsoils, respectively. The forest samples had higher LOI:WB-C ratios than the subsoils from oil palm settings (1.94 vs 1.84). These values suggest that the standard factor of 1.724 to correct OSM to SOM for tropical soils is untenable. The values to convert CNS and WB-C values of tropical topsoils/subsoils to SOM or LOI should be 2.5 or 1.9, respectively. Our results indicate a significant difference in the soil organic carbon (SOC) of tropical lowland peats depending on the method used.     

生物质炭对旱作土壤生物性状及养分有效性的调控效应

通过盆栽试验研究了生物质炭施用对贵州中部地区旱作土壤微生物群落数量、酶活性和土壤养分有效性的影响。结果表明:对不同类型旱作土施用5%～15%(炭/土质量比)的生物质炭后,黄泥土、黄砂土中真菌、放线菌、细菌数量和硝化细菌、氨化细菌数量以及磷酸酶、过氧化氢酶、脲酶活性均表现出明显的增加,特别是黄砂土;而大泥土中放线菌、真菌数量和硝化细菌数量以及磷酸酶和过氧化氢酶活性出现较明显的提高,但氨化细菌数量及脲酶活性出现大幅度降低。此外,黄泥土、黄砂土施生物质炭后有效N、P、K、Ca、Mg、B含量表现出不同程度的增加,但土壤有效Fe、Mn、Cu、Zn含量则出现不同程度的下降;而大泥土中有效P、K、Fe、Mn、Cu、B的含量呈现不同程度的提高,但土壤有效N、Ca、Mg、Zn的含量出现不同程度的减少;其中这3类旱作土壤施炭后土壤有效Zn含量均表现出显著的下降。黄泥土、黄砂土及大泥土施用5%～15%的生物质炭后均能明显提高白菜及莴笋的产量,其中黄砂土施生物质炭的增产效果最好,其次是大泥土。不同类型旱作土壤施炭后土壤有效性养分数量变化存在较大的差别,施用生物质炭时要根据土壤特性配合使用一定比例的氮、磷、钾及适量的微量元素肥料,更有利于促进作物的生长。     

植被恢复对亚热带侵蚀红壤团聚体养分分布的影响

为深入了解不同植被恢复年限下土壤团聚体养分分布特征,以典型红壤侵蚀区福建省长汀县河田地区恢复年限分别为0,5,10,15,30,80a的坡地土壤为研究对象,分别对0—20cm和20—40cm土层不同粒径团聚体养分含量进行测定,并分析了它们与不同团聚体的相关关系。结果表明:(1)植被恢复过程中,土壤团聚体有机碳、全氮、全磷、全钾、速效磷和速效钾含量的变化范围分别为2.06~27.71g/kg,0.54~2.12g/kg,0.034~0.171g/kg,2.20~6.89g/kg,0.31~3.30mg/kg和7.35~85.71g/kg;(2)有机碳、全氮、全磷和速效磷含量随着团聚体粒径的减小总体上表现出显著升高趋势(P0.05),全钾和速效钾含量无明显差异(P0.05);(3)随植被恢复年限增加,各粒径团聚体中有机碳、全氮、全磷、速效磷含量总体上呈显著升高趋势(P0.05),全钾含量先升高后降低,而速效钾含量表现出波动增加趋势;(4)恢复初期(0a和5a)不同土层间团聚体养分含量无明显变化(P0.05),其它恢复年限0—20cm土层团聚体有机碳、全氮、全磷、速效磷和速效钾含量显著高于20—40cm土层(P0.05);(5)团聚体对土壤养分的贡献率表现为(5mm)(2~5mm)(0.5~1mm)(1~2mm)(0.25~0.5mm)(0.25mm),2mm粒径养分贡献率达34.18%~49.93%,土壤养分含量与0.25mm粒径相关性较强(P0.01)。植被恢复在降低土壤侵蚀的同时,土壤团聚体养分含量明显增加,土壤结构得以改善,养分固持能力得到加强。     

Soil Characteristics and Mineral Nutrient in Wild Jatropha Population of India

Abstract

Mature leaves of naturally occurring Jatropha curcas plants and soils samples were collected from four different populations to determine the soil characteristics, soil‐available nutrients, and leaf nutrient contents. This study provides a reliable account of the endogenic concentrations of nutrients present in jatropha leaves. Soil manganese [diethylenetriamine pentaacetic acid (DTPA)‐Mn] was the only soil‐available nutrient significantly correlated with its content in the plant. Relationships between soil characteristics, available nutrient in soil, and their content in plant leaves were also attempted.     

磷石膏改良强酸性黄壤的效应研究

采用盆栽试验,以耐铝能力弱的高粱和强酸性黄壤为研究对象,探讨了磷石膏对强酸性环境高粱生长、养分平衡以及对土壤有效养分和交换铝的影响。结果表明,在强酸性黄壤上,由于铝毒作用,即使施足氮磷钾肥,高粱也生长不良;施用磷石膏和石灰的高粱生长正常,各生物学性状均极显著优于对照,施磷石膏高粱长势更优于施石灰者,高粱干重与磷石膏、石灰的施用量呈二次曲线变化(回归方程分别为:y=6.88 11.92x-1.65x2,R=0.983;y=6.88 6.39x-0.72x2,R=0.996),高粱株高和根长与磷石膏、石灰的施用量也呈二次曲线变化;磷石膏降低酸性黄壤铝毒、提高植物钙含量的效果略逊于石灰,在提高植物营养三要素(特别是磷、钾元素)的作用方面优于石灰,施磷石膏高粱磷、钾含量较石灰处理分别提高117.0%~200.0%和13.0%~14.8%;施磷石膏生长良好的高粱植株氮/磷、氮/钾、钾/磷比分别为6.8~7.1,1.2~1.3和5.4~5.6,比值适中、变幅小,氮/铝、磷/铝、钾/铝、钙/铝比分别是对照植株的1.9~2.0倍,5.8~6.3倍,1.8~2.1倍和2.0~2.5倍,改善和调节了高粱体内氮、磷、钾、钙养分的平衡;施磷石膏的土壤有效氮、磷、钾、钙较对照极显著增加,土壤有效磷、钾分别比施石灰提高41.8%~114.2%和59.4%~67.5%,施石灰的土壤有效磷、钾与对照差异不显著。     

旱塬长期施肥对冬小麦产量及土壤养分的影响

该通过８年的小麦连作定位施肥试验，结合室内分析，探讨了施用不同肥料对作物产量和土壤养分的影响。结果表明：１、Ｍ、ＮＰ、ＮＰＭ施用能够稳定增产；增产为４９．４％－１４１．６％，以ＮＰＭ配施效果最好，其次为ＮＰ配施；２．Ｍ、ＮＰ、ＮＰＭ施用，增加土壤有机质（ＮＰ配施影响不大），全氮，碱解氮，速效磷和无机磷组分的含量。Ｎ．Ｐ单施，只增加土壤相应元素含量。３．在生产中，要提倡ＮＰＭ配施，在有机肥短缺时，