Evaluation of Soil Nutrient Content and Fertility in Main Dry Farming Regions of Laos

[Objectives]To evaluate the status of soil nutrient and fertility in main dry farming regions of Laos,and to explore differences in soil nutrient content between regions and crop types.[Methods]By collecting 57 soil samples in the 0-20 cm layer of the main dryland in southern and northern provinces of Laos.Soil pH,organic matter,total nitrogen,available nitrogen,available phosphorus,available potassium,exchangeable calcium,exchangeable magnesium and available zinc content were analyzed.[Results]The soil in the main dry farming regions of Laos was acidic,the overall fertility level was good,and the exchangeable calcium and magnesium contents were low.There were differences in soil nutrient content in the dry farming regions of southern and northern Laos.Drylands where cassava and maize were growed had higher fertility.[Conclusions]It is suggested to apply lime or alkaline fertilizer in the dry land with acid soil to increase soil pH and increase the supply of soil calcium and magnesium.Organic fertilizer should be applied to improve soil water retention capacity,and it is necessary to pay attention to the fertilization ratio of macroelements to balance fertilization.

Film-mulched continuous ridge-furrow planting improves soil temperature,nutrient content and enzymatic activity in a winter oilseed rape field,Northwest China

Film mulching system is a widely employed agricultural practice worldwide. However, the effects of different planting and mulching patterns on soil nutrient content and enzymatic activity have not been well documented. In this study, we examined the impact of four planting and mulching patterns（including control, flat planting without mulching; M1, flat planting with film mulching; M2, ridge-furrow planting with film mulching on both ridges and furrows; and M3, ridge-furrow planting with film mulching on continuous ridges） on the seed yield of winter oilseed rape, soil moisture, soil temperature, soil organic carbon（SOC） content, soil nutrient content, and soil enzymatic activity over three growing seasons from 2012 to 2015 in a winter oilseed rape field in the semi-arid area of Northwest China. Seed yield of winter oilseed rape, soil moisture, soil temperature, enzymatic activities, and contents of nitrate-nitrogen, available phosphorus, and available potassium were all significantly higher in mulching treatments（M1, M2 and M3） than in control treatment over the three growing seasons, whereas SOC content was significantly lower in mulching treatments than in control treatment during 2013–2014 and 2014–2015. Among the three mulching treatments（M1, M2 and M3）, the M3 treatment showed consistently higher seed yield, SOC content, nutrient contents, and enzymatic activities than the other two treatments. Seed yield of winter oilseed rape was 41.1% and 15.0% higher in M3 than in M1 and M2, respectively. SOC content and soil enzymatic activities in the top 0–20 cm soil layers and nitrate-nitrogen content in the top 0–30 cm soil layers were all significantly higher in M3 than in M1 and M2. Therefore, we advise the ridge-furrow planting with film mulching on continuous ridges（i.e., M3） as an efficient planting and mulching pattern for sustainably improving the seed yield of winter oilseed rape and preserving soil fertility in the semi-arid area of Northwest China.

Changes in Soil Organic Matter,Nitrogen and Phosphorus Contents during Decomposition of Pear Branches

[Objectives]To investigate the changes in soil organic matter,nitrogen and phosphorus content in the decomposition process of Korla fragrant pear branches by indoor mixed culture.[Methods]The branches of Korla fragrant pear in the orchard were collected and returned to the field for a period of 150 d for indoor mixed culture.[Results]Different ages of Korla fragrant pear branches have different effects on soil nutrient content during the simulated return to field decomposition process.Compared with the control in the same period,the treatment of returning to field reached a significant level(P<0.05).Compared with the control,the average values of organic matter,total nitrogen and available phosphorus content in treatment 1 and treatment 2 increased by 2.16 times and 1.93 times,61%and 59%,5.88 times and 6.88 times,respectively;compared with the control,the average increase performance of the alkaline hydrolysis nitrogen content of the two treatments was basically the same,and the treatment 2 was the best;compared with the control,the average total phosphorus content of treatment 1 and treatment 2 increased but not significantly.[Conclusions]The contents of soil organic matter,nitrogen and phosphorus were all increased during the decomposition of pear branches,and the overall improvement effect of 10-year-old trees was better than that of 5-year-old trees.Returning the pruned branches to the field can provide a reliable theoretical basis for solving the problem of organic fertilizer shortage in orchards,and also can ensure technical support for improving soil fertility and improving the rhizosphere micro-environment of pear trees.

Distribution of Nutrient Content in Soil and Leaves of Adult Areca catechu Trees

The annual dynamic changes of nutrient content in soil and leaves of adult Areca catechu trees in the A.catechu producing area Tunchang were studied by fixed point observation method to provide the scientific basis for the rational fertilization of A.catechu.The results showed that the soil of the A.catechu plantation was weakly acidic on the whole,and soil pH was 5.53.Soil phosphorus content was extremely low,only 5.46 mg/kg.Nitrogen content in A.catechu leaves was the highest( up to 20.24 g/kg),while phosphorus content was the lowest( only 0.31 g/kg).The differences in nutrient content were related to the characteristics of nutrient demand.There was a difference in nutrient content of A.catechu leaves during the annual growth period.Because the maximum nutrient requirement period of A.catechu trees was from April to September,the important fertilization period of A.catechu trees was also from April to September.

Assessment cultivated period and farm yard manure addition on some soil properties, nutrient content and wheat yield under sprinkler irrigation system

This study examined changes in some soil hydrophysical, chemical properties and wheat yield (grain;straw yield, N, P, K, Protein and carbohydrates contents) as trends under two cultivated period 10 and 25 year and Farm Yard manure (FYM) addition under sprinkler irrigation system on a newly reclaimed soils, Nubaria, Beheira Governorate, Egypt. Obtained results noticed that cultivation period has more pronounced effect than FYM addition on soil water content at field capacity, wilting point and available water with increase percent 15.1%, 9.3%;19.0% and 25.7%, 19.5% and 30.0% for FYM and cultivation period comparing with control one. Hydraulic conductivity values were strongly affected by cultivation period and FYM addition and significantly decreased values by about 18.9% and 12.1% in same sequences. Wheat straw content from protein had a superior effect under 25 than 10 years cultivated periods with values 61.9 and 6.7 comparing with control, respectively as affected by FYM addition, while FYM alone improved protein content in straw by about 31.9% comparing with untreated one. Slightly increase in straw protein content was attained relative to the increase of cultivated period by about 7.8%. Nutrients content in grain is more than FYM, where the increase percentage were 5.2%, 13.5%;3.8% and 26.5, 21.3;22.6 comparing cultivated periods 25 with 10 years and FYM addition with control, respectively. FYM individually under two studied cultivated periods is more effective under 10 years (28.0%, 25.2%;15.1%) than the 2nd one (25.1%, 25.2%;15.1%) comparing with untreated FYM plots. While N, P and K content in wheat straw had unclear trend and the increase were 6.8, 23.23;56.5% and 62.9, 6.0;29.8 as a result of FYM addition under 10 and 25 years cultivated periods, respectively. The highest values of protein and carbohydrates content in wheat grains as affected by studied factors were 12.86% and 67.43%) were obtained under cultivated period 25 years after FYM addition. Cultivated periods had a highly significant effect on the field water use efficiency values of grain more than the effect of FYM. The highest values of grain and straw yield were recorded at 10 years cultivated periods + treated FYM (2966.8 kg/fed) and 25 years cultivated periods treated with FYM (3835.6 kg/fed). Cultivated periods increased grain and straw yield of wheat crop by about 57.6% and 8.3%. Whereas, FYM increased grain and straw yield by about 39.8% and 58.8% relative to the control, respectively.

Rules of Changes in Soil Nutrients and Enzyme Activities of Larix principis-rupprechtii in Different Forest Ages

In this study,three different ages of Larix principis-rupprechtii forests in 5,10 and 20 years were selected as the research objects,and the changes in soil nutrient and soil enzyme activities in different growth stages were analyzed. The results showed that the contents of organic matter and available phosphorus in the soil of different growth stages showed a significant downward trend with the increase of soil depth.For different forest ages in the same soil layer,the soil available phosphorus content declined with the increase of the forest age. The organic matter content of 40-60 cm in 20 years of forest age was the lowest in July,which was 4. 17 g/kg,significantly lower than that in other soil layers. Besides,the soil available phosphorus content of 5 years of forest age reached the maximum in July,with an average of 4. 44 mg/kg,which was higher than the available phosphorus content in soil in May and September,but the difference between the three months was not significant. The changes in ammonium nitrogen and nitrate nitrogen content in soil with different forest ages were consistent with the changes in the soil depth,showing a downward trend. In the new leaf stage,the ammonium nitrogen content of the L. principis-rupprechtii forest land in5 years of age at 20-40 and 40-60 cm of the soil depth was 13. 47 and 9. 09 mg/kg,respectively,which was 46. 9% and 64. 2% lower than that at 0-20 cm( 25. 36 mg/kg) of the soil depth. The soil nitrate nitrogen content of 20 years of forest age was 19. 24 mg/kg,which was25. 8% lower than that of 10 years of forest age,showing significant difference( P < 0. 05). In addition,with the increase of the age of L. principis-rupprechtii,soil catalase( CAT),alkaline phosphatase( ALP) and urease( Ure) decreased,and the decline of ALP was slow,while CAT and Ure decreased significantly. In summary,it is concluded that the soil fertility of forest land declined with the increase of forest age on the basis of change trend of soil nutrient and soil enzyme activity in the surveyed forest age.

Status of Soil Nutrients in Citrus Orchards of Guangxi

Based on the investigation of 56 soil samples( 0-30 cm) in citrus orchards of Guangxi,the content of soil organic matter and available nutrients as well as their correlations in the citrus orchards were studied. The results showed that soil was rich in organic matter,and the proportion of soil samples deficient in available N,P and K was 30. 36%,32. 14% and 28. 57% respectively. Soil was seriously deficient in soil available Ca,Mg and B,while the content of soil available Fe and Cu in soil was too high. There were significant or extremely significant positive or negative correlations between soil pH,organic matter and several available nutrients. It is recommended to apply Mg fertilizer,B fertilizer,lime or other alkaline fertilizer and reduce the spraying of fungicides containing Cu in the citrus orchards.

Study on Available Nutrients of Soil in Fenlong by a New Farming Method

Taking 0-30 cm, 0-40 cm, 0-50 cm, 0-60 cm of dry land Fenlong and 0-40 cm paddy field as samples of soil profile with corresponding original soil as the control group, we measured content of organic matter, quick-acting N, quick-acting P and quick-acting K, effective B, Cu, Zn and Mn. Results indicate that available nutrients in soil after Fenlong were higher than original soil. For dry land, the increase of organic matter, quick-acting N, quick-acting P and quick-acting K is 3.02%-35.16%, 6.80%-39.54%, 2.81%-44.46%, and 7.72%-53.71% respectively. There is also increase in effective content of trace element, B, Cu, Zn and Mn. For paddy field, the increase of organic matter, quick-acting N, P and K is 19.64%, 24.02%, 24.27% and 57.78% respectively. Besides, there is also increase in content of trace element, B, Cu, and Zn. On the basis of analysis, we put forward the new theory of crop cultivation "root" theory.

Laboratory Design Criteria for Monitoring Biostimulated Bioremediation of a Crude Oil Contaminated Soil in Niger Delta Using Total Petroleum Hydrocarbon

The remediation of crude oil-impacted soil has always been a challenge in different soil environments and climatic conditions. Bioremediation technology has offered a breakthrough in restoring crude oil-impacted soil/sediment in muddy, dry soil and wetlands. Though, there have been varied environmental conditions that have hampered the success of the bioremediation process. This study has evaluated the effectiveness of a biostimulated bioremediation of crude oil-impacted soil using some design criteria—nutrient amendment (NPK fertilizer) and moisture content. Soil sample sets—A, B, C, D, E, F, and G were impacted with crude oil at a ratio of 10 g/kg and amended with varying amounts of nutrient 30, 60, and 80 g of N.P.K fertilizer. The medium for the inoculation of the nutrient was water and the volume of water applied varied from 30% to 80% saturation. The soil sample sets were harvested at an interval of 3 months for 180 days to determine the concentration of total petroleum hydrocarbon left in the soil. The analysis of the total petroleum hydrocarbon was achieved using a GC-FID with a capillary column and autosampler. Soil samples were extracted with mixed solvent dichloromethane and acetone at a 1:1 ratio. The total petroleum hydrocarbon results show that biostimulated bioremediation achieved better results in soil sample sets with low moisture content (30% water saturation) and moderate nutrient amendment. The biodegradation of the sample sets with high water saturation and a high nutrient amendment was slow with a higher amount of total hydrocarbon content at the end of the 180 days. The variability in the hydrocarbon degradation pattern of contaminated soil shows that biostimulated bioremediation achieved better results in soils with low moisture content than in soil environments with high water content (saturation). More so, nutrient overdosing of the substrate hampered the effectiveness of the remediation process.

污泥生物炭添加对黑麦草和土壤养分特性的影响

为探讨污泥生物炭(Sludge biochar,C)和改性污泥生物炭(Modified sludge biochar,GC)添加对黑麦草(Lolium perenne L.)和土壤养分特性的影响,本试验以C和GC为材料,设置不同添加水平(0%,5%,10%,15%,20%)种植黑麦草,测定黑麦草和土壤养分等指标。结果表明,添加C、GC均促进了黑麦草的生长及其茎叶和根含水量的提高,5%的添加水平显著提高了黑麦草茎叶和根的干重。C、GC添加对黑麦草TN含量的提高效果最显著,其次为TK。C添加对提高黑麦草生物量的影响程度大于GC,而对黑麦草养分含量及其吸收累积,GC大于C。应用C、GC可提高土壤有机质和全氮含量,降低土壤pH,碱解氮和速效磷受生物炭类型影响。因此,土壤中添加5%~10%比例的C或GC对植物的生长有促进作用,有利于提高土壤的养分含量。

保水剂施用量对西南紫色土水分和养分特征及烟叶品质的影响

[目的]揭示保水剂聚丙烯酸钾不同施用量对西南烟区紫色土水分、土壤孔隙状况、土壤养分特征及烟叶品质的影响,为缓解季节性干旱区植烟土壤水分缺乏及高产优质的烟草生产提供重要参考。[方法]采用随机区组设计,定量研究了不同保水剂施用量条件下的紫色土水分、养分及烟叶品质特征。[结果]保水剂添加后,土壤pH值变化范围为7.4~7.7,土壤总孔隙度、毛管孔隙度、土壤饱和含水量、田间持水量、毛管含水量均呈先增大后减小变化规律,当保水剂施用量为150 kg/hm^(2)时,土壤容重达到最低值,土壤总孔隙度和毛管孔隙度、土壤饱和含水量、毛管含水量均达到最大值。土壤的阳离子交换量(CEC值)呈现出波动式变化。土壤有机碳、全钾和速效钾含量随着保水剂施用量的增加呈先增加后降低的趋势,土壤全氮、全磷、碱解氮和速效磷含量呈逐渐增加趋势。土壤容重呈现出先减小后增大的趋势。烟叶氯含量、总氮含量变化为上部叶<中部叶<下部叶。随着保水剂施用浓度的增加,烟叶氯含量呈波动变化。中上部烟叶含钾量高于下部烟叶含钾量且随保水剂施用浓度的增加略有增加。烟碱含量变化为上部叶>中部叶>下部叶,且烟碱含量与保水剂施用浓度相关性较弱。烟叶还原糖和总糖的变化趋势较为一致。不同部位的烟叶钾氯比表现为上部叶>中部叶>下部叶,且最随着保水剂施用浓度的增加,烟叶钾氯比呈波动态变化。不同叶位烟碱/总氮比和糖碱比均表现为上部叶<中部叶<下部叶,且随着保水剂浓度的增大,均表现为递增趋势。植烟土壤全氮含量与不同叶位的烟叶氯含量、上部叶含钾量、还原糖含量之间均呈显著正相关关系(p<0.05)。不同叶位烟叶氯含量、还原糖含量、上部烟叶钾含量、下部烟叶烟碱含量均与土壤有机碳间存在显著正相关关系(p<0.05)。[结论]保水剂为150 kg/hm^(2)对于西南紫色土的改良效果最佳,研究可为植烟土壤抗旱性能增强及烟叶品质的提升提供科学依据。

不同前茬作物对信阳市平桥区植烟土壤养分的影响

为研究不同前茬作物对植烟土壤肥力的影响,从信阳市平桥区采集166个土壤样品进行养分测定。结果表明:土壤pH值总体处于适宜水平(5.5~<7.0),玉米前茬土壤酸化程度普遍较高,花生前茬土壤pH值大多处于适宜水平;土壤有机质含量总体处于适宜或偏低水平,烟叶前茬土壤有机质含量有83.33%处于适宜水平,其余前茬作物的土壤有机质含量偏低,需及时补充有机肥;不同前茬的土壤碱解氮平均含量均超过100 mg/kg,处于中等偏上水平,应控制氮肥的施用量;土壤有效磷含量水稻前茬的较高,其他前茬土壤有效磷含量均处于适宜水平,但变异系数较大;土壤速效钾平均含量均处于适宜水平,其中花生前茬的土壤速效钾含量处于适宜水平的比例最高,为83.64%;除水稻前茬外,其他前茬植烟区土壤中氯离子平均含量均处于适宜水平,但整体来看氯离子含量偏高比例较大,在种植过程中应及时调控。

有机肥与化肥配施对夏播玉米产量和土壤肥力的影响

为探索有机肥与化肥配施对全株玉米产量和土壤肥力的影响,以乐玉1号玉米为试材,通过田间试验,设置不施肥(CK)、全部化肥(HF)、牛粪单施(N1)、牛粪替代20%化肥(N2)、牛粪替代30%化肥(N3)、羊粪单施(Y1)、羊粪替代20%化肥(Y2)、羊粪替代30%化肥(Y3)共8个处理,测定全株玉米干草产量、氮磷钾素积累量和重金属含量以及土壤理化性质等相关指标。结果表明,Y2和Y3处理的全株玉米干草产量和氮磷钾积累量优于其他处理;N2处理的Cu积累量和Y1处理的Zn积累量最高;0~20cm土层以N3处理的有机质、速效磷、铵态氮、硝态氮和阳离子交换含量最高。可见,低总氮水平下,羊粪替代20%和30%化肥处理对全株玉米生长及养分积累有积极作用,牛粪替代30%化肥改良土壤肥力效果较好。

生物炭和有机肥配施对土壤养分影响的研究进展

为了解决单施有机肥在用量、肥效以及养分淋失方面并同时提高土壤养分利用效率等问题,以“生物炭”、“堆肥”“生物炭有机肥配施”、“土壤性质”、“农作物养分”等为关键词,在Web of Science、Google Scholar、中国知网等网站搜索相关文献归纳并总结。结果表明:(1)生物炭能够改善堆肥的腐熟程度,增加微生物群落的丰度,降低有机肥中养分流失的风险,从而有效减少传统的堆肥对环境的影响;(2)生物炭和有机肥配施后,可提高土壤含水量,并对不同类型土壤的有效磷、速效钾含量均有不同程度地提高。同时,还能为土壤中的生物和微生物提供更好的生活物质及环境;(3)二者配合施用可以增加农作物的产量,改善其氮、磷、钾含量,但不同农作物对其响应不同。生物炭与有机肥配合施用,对提升土壤肥力和植物养分含量具有良好的效果,其效果随施用比例、土壤类型、农作物种类等因素的不同而异。本研究可对畜禽粪便资源在农业生产中的高效利用提供参考。

三江源区退化高寒草甸植被生物量和养分的动态变化

[目的]探索三江源区高寒草甸草地植被-土壤系统生物量和土壤养分的动态变化,以利于草地适应性管理和开展草地生态修复相关工作。[方法]以中度退化高寒草甸为研究对象,于2020-2022年的7、8和9月持续观测高寒草甸植被生物量(地上生物量和根系生物量)、植被(地上部和根系)和土壤(0~15和15~30 cm)全氮、铵态氮、硝态氮、速效氮、有机碳、全磷和全钾含量。植被生物量、植被养分和土壤养分在不同月份间的动态变化用单因素方差分析(One-way ANOVA)进行比较。[结果]不同月份间植被生物量存在显著的递增趋势(2021年除外)(P<0.05,下同),整体表现为9月最大,地上生物量最大值分别为74.58和72.80 g/m^(2),根系生物量最大值分别为39.82和57.32 g/m^(2)。植被(地上部和根系)和土壤(0~15和15~30 cm)养分含量存在显著的月际动态,具体表现为8月达到最大值。植被生物量与植被地上部和根系的全氮含量显著相关,与土壤0~15和15~30 cm土层的全氮含量呈显著正相关。[结论]高寒草甸植被(地上部和根系)养分与土壤(0~15和15~30 cm土层)养分在8月达到峰值。研究结果可为高寒草甸养分管理领域学者凝练科学问题提供参考。

秸秆还田与沼液配施对盐渍化土壤养分及酶活性的影响

于2023年开展120 d的室内培养试验,设置棉秆全量还田(AS)、低量沼液单施(LB)、高量沼液单施(HB)、棉秆还田配施低量沼液(AS+LB)、棉秆还田配施高量沼液(AS+HB)共5个处理,分别于3、6、10、20、30、40、60、80、100、120 d进行破坏性采样,分析不同处理土壤主要理化指标和关键酶活性的变化,为南疆棉花秸秆在盐渍环境中的高效腐解和沼液合理利用提供参考。结果表明,棉秆还田配施沼液处理的土壤有机质变化呈现快速增加(0~10 d)和慢速积累(>10 d)两个阶段。与棉秆全量还田相比,高量沼液配施处理土壤有机质、全氮、有效磷和速效钾含量分别增加25.15%、35.26%、79.25%和66.90%,土壤过氧化氢酶、碱性磷酸酶和蔗糖酶活性分别增加90.67%、66.54%和44.25%,土壤电导率也有所提升。冗余分析(RDA)揭示了有机质是土壤酶活性变化的主控因子,解释了方差变异的54.30%。因此,秸秆还田与沼液配施能够增加棉田盐渍化土壤有机质和全氮含量,促进酶活性增加,但沼液过量配施会增加土壤盐渍化风险。

长期施用秸秆生物炭对土壤养分及作物生长的影响

于2011—2020年在山西榆次区开展田间定位试验,设不施肥(CK)、不施肥施生物炭(CK+B)、施氮磷钾肥(NPK)和氮磷钾肥配施生物炭(NPK+B)共4个处理,种植模式为玉米-高粱轮作,研究有机碳施用5 a和10 a对0~20 cm土层土壤有机质、全氮、有效磷、速效钾含量和土壤蔗糖酶、脲酶、碱性磷酸酶、过氧化氢酶活性的影响,及各处理累积秸秆干物质量、养分积累量和籽粒产量的变化。结果表明:(1)生物炭施用5 a和10 a后,与CK比较,CK+B处理土壤有机质含量分别提高了46.3%和61.2%;与NPK比较,NPK+B处理土壤有机质含量分别提高了67.8%和77.7%。施用10 a后CK+B处理全氮含量显著高于CK处理,但NPK+B和NPK处理土壤全氮含量间没有显著差异。生物炭对土壤速效钾含量提升效果显著,施用10 a后CK+B和NPK+B处理土壤速效钾含量较CK和NPK处理提升86.4%~46.6%。(2)生物炭施用10 a显著提升了土壤蔗糖酶和碱性磷酸酶的活性,增幅分别为11.4%~11.9%和7.9%~16.2%,但对脲酶、过氧化氢酶和有效磷没有影响。(3)生物炭施用10 a明显提高了抽穗期和成熟期作物地上部磷和钾的累积量,但对成熟期氮素累积吸收量没有影响,无论施肥与否,生物炭对累积籽粒产量没有显著影响。综上可知,长期施用秸秆生物炭可显著提升土壤有机质和速效钾含量,对土壤全氮和有效磷的影响较小,显著提高植株磷和钾吸收,因此在施用秸秆生物炭时应考虑氮的补充,降低钾投入。

贵州省桐梓县耕地表层土壤养分元素有效性研究

通过研究贵州省桐梓县耕地表层土壤养分元素有效性及其影响因素,为耕地资源规划、发展现代农业提供科学依据。根据桐梓县耕地质量地球化学调查评价所获得的表层土壤有效态样品,对其养分元素(指标)测试分析,探讨耕地表层土壤养分元素及其有效态的含量、分布特征、等级状况及影响因素。结果表明,研究区耕地表层土壤养分元素全量整体较丰富,硼、钼、锌全量以丰富等级为主,分别占总样本数56.34%、65.49%、77.96%;氮全量以较丰富为主,占比41.16%;而磷全量以较缺乏为主,占比32.23%。有效量整体较缺乏,速效磷、有效钼以缺乏为主,分别占比46.05%、30.14%;有效硼、速效钾以较缺乏为主,占比分别为64.66%、50.94%;而有效锌较丰富,占比50.83%。研究区耕地表层土壤养分元素全量是其有效量的主控因素,养分元素有效性受表生地球化学及土壤理化性质的影响;不同的地质单元、土壤类型、土地利用类型中土壤养分元素有效性差异性显著;增加阳离子交换量可以促进土壤养分元素有效量的转化,提高土壤中有机质含量能增加养分元素有效性。