热带农业生态系统土壤肥力与植物养分综合管理研究进展

The greatest challenge for tropical agriculture is land degradation and reduction in soil fertility for sustainable crop and livestock production.Associated problems include soil erosion,nutrient mining,competition for biomass for multiple uses,limited application of inorganic fertilizers,and limited capacity of farmers to recognize the decline in soil quality and its consequences on productivity.Integrated soil fertility management(ISFM) is an approach to improve crop yields,while preserving sustainable and long-term soil fertility through the combined judicious use of fertilizers,recycled organic resources,responsive crop varieties,and improved agronomic practices,which minimize nutrient losses and improve the nutrient-use efficiency of crops.Soil fertility and nutrient management studies in Ethiopia under on-station and on-farm conditions showed that the combined application of inorganic and organic fertilizers significantly increased crop yields compared to either alone in tropical agro-ecosystems.Yield benefits were more apparent when fertilizer application was accompanied by crop rotation,green manuring,or crop residue management.The combination of manure and NP fertilizer could increase wheat and faba bean grain yields by 50%–100%,whereas crop rotation with grain legumes could increase cereal grain yields by up to 200%.Although organic residues are key inputs for soil fertility management,about 85% of these residues is used for livestock feed and energy;thus,there is a need for increasing crop biomass.The main incentive for farmers to adopt ISFM practices is economic benefits.The success of ISFM also depends on research and development institutions to provide technical support,technology adoption,information dissemination,and creation of market incentives for farmers in tropical agro-ecosystems.     

Agronomy and Physiology of Tropical Cover Crops

Cover crops are important components of a sustainable crop production system. They can be planted with plantation crops such as cacao, coffee, banana, rubber, and oil palm or in rotation with cash crops. Their use in a cropping system is mainly beneficial for soil and water conservation, recycling of nutrients, control of pests and improved microbiological activities. However, beneficial effects depend on the selection of appropriate cover crops and their management. Hence, understanding their agronomy and physiology is fundamental for their use in sustainable cropping systems. Growth and development of a crop (physiological aspects) is determined genetically as well as influenced by environmental variables. This information can be useful in improving production of these crops and, consequently, their incorporation in farming systems, wherever it is possible. There are hundreds of tropical cover crops and, therefore, it is not possible to include all of them in one article. Hence, selected cereals and legumes are included.     

Effect of long-term chemical and organic fertilization on rice productivity,nutrient use-efficiency,and balance under a rice-fallow-rice system

Nutrient sources and management influence soil properties and crop productivity indicating that sustained crop production needs nutrient rate specific tuning after certain periods of time. We hypothesize that long-term use of organic and inorganic nutrient sources maintains soil fertility and improve crop production. Yield and nutrient use efficiencies have not been evaluated in Bangladesh from long-term fertilizer trials focusing on adaptation strategies for sustained food production. So, the objectives of the present investigation were to examine the effects of organic and inorganic amendments on yields and soil properties under a rice-fallow-rice system. The experiment was initiated in 1985 with 12 treatments under dry season irrigated rice culture at the Bangladesh Rice Research Institute, Gazipur. The effects of organic and inorganic nutrient sources were evaluated under missing element techniques. The contributions of nitrogen (N), phosphorus (P), and potassium (K) fertilizers to yields were more in the dry season but the role of P was negligible in the wet season. The omissions of N, P and K nutrients are not suitable management option for rice cultivation during dry and wet seasons, although P can be omitted in the wet season provided its full dose is applied in the dry season. The combined use of organic and inorganic nutrient sources are the best option for improving rice productivity and sustaining soil fertility in a rice-fallow-rice system in Bangladesh.     

Soil Fertility and Plant Nutrition Research Under Controlled Conditions: Basic Principles and Methodology

In modern agriculture, use of essential plant nutrients in adequate amounts and proper balance is one of the key components in increasing crop yields. Further, in developing crop production technologies, research work under field and controlled conditions is necessary to generate basic and applied information. In addition, research is very dynamic and complex due to variation in climatic, soil, and plant factors and their interactions. This demands that basic research information can only be obtained under controlled conditions to avoid or reduce effects of environmental factors on treatments. Hence, the objective of this article is to discuss basic principles and methodologies of research in soil fertility and mineral nutrition under controlled conditions. Topics discussed are soil and solution culture experimental techniques including, fertilizer application and planting, liming acid soils, experimental duration and observations, composition of nutrient solutions, preparation and sources of iron (Fe) in nutrient solutions, pH of nutrient solutions, and stable supply of nutrients in the solution culture.     

浅谈“十四五”土壤肥力与土壤养分循环分支学科发展战略

土壤肥力与土壤养分循环分支学科是土壤学科中应用性较强的学科,悠久的发展历史积累了极为丰富的文献资料,在评价和利用土壤资源,提高作物产量和养分利用率,减少环境污染中发挥着重要作用。"十四五"期间土壤肥力与土壤养分循环分支学科应加强土壤养分转化过程、速率、产物及其影响因素的基础性研究。鉴于我国大宗作物种植强度下降,集约化设施种植面积增加的两极化发展现状和减肥减药维持生态环境安全的国家需求,"十四五"期间,土壤肥力与土壤养分循环分支学科应加强以下针对性研究:1)休耕轮作对土壤肥力的影响及通过休耕轮作维持和提高土壤肥力的原理、途径和方法;2)高度集约化种植条件下快速恢复土壤肥力,保持土壤健康和有效利用土壤养分的科学管理原理、途径和方法;3)实现土壤-作物-环境相互契合,充分发挥土壤肥力,高效利用土壤养分的基础科学问题。     

Maintaining soil fertility under increasing land use pressure in the Middle Mountains of Nepal

Abstract. Nepal is facing a serious problem of being unable to maintain soil fertility in agriculture and forestry. Land use practices initiated over the past 10–15 years have resulted in insufficient nutrient inputs, while biomass use and production have increased. Changes in forest soil fertility have resulted from intensive use of forest biomass for animal feed and collection of forest litter for use in agriculture. The agricultural fertility changes have resulted from intensifying annual crop rotations from 1.5 to 2.5 crops and insufficient inputs. The removal of biomass from the forest has curtailed the natural organic cycle by virtually eliminating nutrient inputs.
The soils are very acidic and have little C, N, P and exchangeable bases, but have large amounts of active iron. Basic nutrients are not sustained in agriculture and differences in inputs and management between irrigated and rainfed agricultural systems are becoming visible. Irrigated fields show the largest cation content because of input from irrigation water. Rainfed agricultural sites, which receive the most nutrients (fertilizers and manure), have the highest pH values and C and N contents. All soil fertility conditions are marginal and put into question the long-term sustainability of current levels of production. Alterations in the cropping intensity are needed and the introduction of nitrogen fixing trees and crops seems to be the most viable option towards sustainability.     

Humus balances of different farm production systems in main production areas in Austria

The importance of the soil humus content is indisputable. Soil humus plays an important role in preserving soil fertility and exerts great influence on plant production and yield potential. However, proofing that management‐related changes in the stock of soil organic matter (SOM) have taken place against the background of spatial and temporal variation is a difficult task. In most cases, sampling over a long period of time is needed to verify these changes. Alternatively, potential changes in the SOM stock can be estimated using humus balancing models, which help to identify the need for humus reproduction on a farm. In general, a humus balance is the difference between the humus demand of cultivated crops and humus supply through crops and organic fertilizers. In this study, the ‘Dynamic Humus Unit Method' within the modelling program REPRO was applied to calculate the humus balance for 29 model‐farms that are representative of most of the agricultural production in Austria. Each model‐farm represents a specific production type (PT) and farming system in a defined region or main production area (MPA). This approach gives an overview of the humus balances at a large scale and allows a general trend in Austria to be estimated. Besides differing between conventional and organic farming systems, specific site conditions can also be selected in the model. The constructed model‐farms belong to different PTs such as “forage production”, “cash crops”, “refinement”, and “permanent crops”. The PT “permanent crops” refers to the cultivation of wine. The cropping system of each PT was analyzed in detail, while livestock keeping was considered only when applicable. Positive humus balances were found for all PTs except for permanent crops. The results ranged from –122 to 890 kg C ha^?1 y^?1. Regions and farm structure, e.g., forage production compared to cash crop, were found to have a greater influence than the kind of farming system (i.e., organic vs. conventional farming). Comparing the different PTs, forage production had the highest positive humus balances (219 to 890 kg C ha^?1 y^?1), followed by cash crop (24 to 239 kg C ha^?1 y^?1), refinement (–64 to 402 kg C ha^?1 y^?1) and permanent crops (–122 to –38 kg C ha^?1 y^?1). Regarding the farming system, organic farming led to more humus accumulation than conventional farming due to a higher share of fodder legumes and catch crops and more diverse crop rotations. The results were within the range of available empirical data on SOM change, and it was therefore concluded that the results are reasonable. In general, humus reproduction can be regarded as sufficient for agricultural production.     

种养平衡——农业污染减排模式探讨

种植业与养殖业缺乏协调规划导致“种养分离”日趋明显,由此影响了种养系统间物质循环利用过程,导致畜禽粪便过量对生态环境造成极大危害。为此,从种养系统间物质循环与农业污染之间的内在联系出发,提出“种养平衡”发展模式,分别从以种定养、以养促种的角度探讨了种植业与养殖业平衡发展模式的实现途径：“以种定养”是从种养系统物质循环的角度合理规划养殖规模,防止畜禽粪便过量产出增加环境压力;“以养促种”是通过畜禽粪便无害化处理和科学合理地还田利用等手段,降低畜禽粪便资源化的环境风险。通过建立“以种定养”、“以养促种”的农业生产模式,实现废弃物高效循环利用,降低环境污染风险,从而缓解农业污染减排压力。     

黄潮土养分供应特征及演变规律

１５年定位监测结果表明：不同施肥结构对小麦、玉米产量有明显影响，各处理单产依次为：ＭＮＰＫ〉ＭＮＰ〉ＭＮ〉ＮＰＫ〉ＮＰ〉Ｎ〉Ｍ＾１）〉ＣＫ。长期不施肥区，土壤养分供应不足，产量逐年下降。基础地力贡献率平均产３７．２％，肥料的增产贡献率为６２．８％。在肥料中有机肥占２５．２％，化肥占７４．８％。在化肥中氮占６４．６％，磷占２７．２％，钾占８．２％。有机肥有明显改土培肥作用，有利土壤物理性改善，增强作     

Permanent–soil monitoring sites for documentation of soil‐fertility development after changing from conventional to organic farming

For monitoring soil fertility after changing farm management from highly conventional to organic farming on the newly established research farm of Kassel University, two permanent–soil monitoring sites were installed in 1999. Representative locations for installing the permanent–soil monitoring sites were selected using geographical information systems (GIS), based on available data from geology, topography, soil taxation, land use, and intensive auger‐borehole records and analysis with a very high spatial resolution of data. The soils are represented by a Luvisol derived from loess and a Vertisol developed from claystone. The soil properties of the two monitoring sites measured immediately after changing to organic farming showed high contents of extractable nutrients as a result of the former intensive fertilization practice during conventional farm management. The microbial soil properties of the two monitoring sites were in the medium range of regional soils. A first evaluation of the development of soil properties was done after 5 y of monitoring. The soil organic‐matter content increased slightly after grass‐clover and after application of farmyard manure. The amounts of K and P decreased clearly at the loess site without application of farmyard manure. At the clay site, the unique application of farmyard manure led to increasing contents of extractable K and P in the top soil. The variation of soil properties increased clearly after perennial crops like grass‐clover and in years after application of farmyard manure.     

Soil Fertility and Plant Nutrition Research Under Field Conditions: Basic Principles and Methodology

In the agricultural science, soil fertility and plant nutrition have played an important role during the 20th century in increasing crop yields. In the 21st century, importance of this field is still expanding due to the limitations of natural resources (land and water), sustainable agriculture, and concern about environmental pollution. In this context, increasing crop yields will be associated with rational use of chemical fertilizers, increasing use of organic sources of nutrients, recycling of plant available nutrients, and exploiting genetic potential of crop species or cultivars within species in efficient use of nutrients. Hence, in the future, increasing crop yields will be a challenge for agricultural and soil scientists. Conducting fertilizer field trials for adequate sources, methods, rates, timing of application along with crop species or genotypes within species, under different agroecological regions are necessary to generate data and their use for achieving maximum economic crop yields. The objective of this article is to present basic concepts and discuss methodology of soil fertility and plant nutrition research under field conditions.     

Comparison of paddy soil fertility under conventional rice straw application versus cow dung compost application in mixed crop–livestock systems in a cold temperate region of Japan

ABSTRACT

After the rice harvest in Japan, rice straw (RS) is usually cut by combine harvester and incorporated into the soil to improve its fertility. In mixed crop–livestock systems, however, RS is collected and used as livestock feed, and cow dung compost (CDC) is then applied to the soil. This system utilizes the residual organic matter from both rice production and livestock husbandry to make each product. CDC application is also considered to improve the fertility of paddy soil. However, the nutrient input from CDC and the effect of CDC application on soil fertility vary among regions and/or soil types. We compared soil fertility between RS application (RS treatment, avg. 32 years) and RS removal plus CDC application (CDC treatment, avg. 21 years) in 79 paddy fields in Mamurogawa town, Yamagata Prefecture, a cold temperate region of Japan, and measured the nutrient contents in the applied RS and CDC. The total C content of RS was significantly higher than that of CDC, whereas the N, P, K, and Si contents of CDC were significantly higher than those of RS. However, there was no significant difference in paddy soil fertility – as measured by soil organic C, total N, CEC, available N, P, and Si, exchangeable K, Ca, and Mg, base saturation percentage, pH, and bulk density – between the treatments. The soil fertility of most fields was adequate by RS or CDC treatment. Thus, leaving RS in paddy fields or removing it and then adding CDC to the paddy fields has a similar effect in maintaining adequate soil fertility for single rice production or rice–livestock production systems.     

Nutrient management on crop productivity and changes in soil organic carbon and fertility in a four–year-old maize-wheat cropping system in Indo-Gangetic plains of India

The aim of this investigation was to prepare and evaluate organic manures (vermicompost, compost and FYM) and mineral fertilizers on crop productivity and changes in soil organic carbon (SOC) and fertility under a four-year-old maize-wheat cropping system. The results demonstrated that yields and nutrient uptake by crops increased significantly in plots receiving manures and mineral fertilizers either alone or in combination than unfertilized control. Application of manures and fertilizers also enhanced SOC, mineral N, Olsen-P and ammonium acetate-extractable K (NH₄OAc-K) after both the crops. Surface soil maintained greater build-up in SOC, mineral N, Olsen-P and NH₄OAc-K than sub-surface soil. Plots amended with manures at 5 t ha^?1 and 50% recommended dose of fertilizer (RDF) had pronounced impact on improving SOC and fertility after both the crops indicating that integrated use of manures and mineral fertilizers could be followed to improve and maintain soil fertility, increase crop productivity under intensive cropping system.     

A comparison of a pasture ley with a maize monoculture on the soil fertility and nutrient release in the succeeding crop

Specialization within agriculture has been a key factor in increasing farm income. The production systems have become increasingly simple, since farmers only grow a small number of crops which have a favourable market price. However, monocultural systems require increasing use of agrochemicals leading to unsustainable environmental costs. In this work, the soil fertility of two plots in a crop rotation previously grown for 5 years as pasture or maize monoculture was evaluated. In the pasture, the upper 0–20 cm soil layer sequestered 17.4 Mg organic C ha^?1 and accumulated 403 kg N ha^?1 more than under maize monoculture. Analytical data from pot experiments showed that soil samples from the pasture plot released significantly more mineral N than soil samples from the maize monoculture. Maize dry matter (DM) yields in 2012 and 2013 were 15.3 and 10.0 Mg ha^?1 in the pasture plot and 8.8 and 8.4 Mg ha^?1 in the maize monoculture plot. Nitrogen recoveries by maize were 175.4 and 68.0 kg ha^?1 in the pasture and 78.3 and 50.3 kg ha^?1 in the maize monoculture plot. The pool of organic matter accumulated during the pasture phase immobilized important nutrients which benefited the succeeding crop as the organic substrate was mineralized.     

Effects of long-term legume cover crop incorporation on soil organic carbon, microbial biomass, nutrient build-up and grain yields of sorghum/sunflower under rain-fed conditions

Low organic matter, poor fertility and erosion are common features of rain‐fed Alfisols in southern India. Build‐up of organic matter is crucial to maintain sustainable production on these soils. The possibility of on‐farm generation of legume biomass [horsegram; Macrotyloma uniflorum (Lam.) Verdc.] by using off‐season rainfall was examined in two field experiments involving sorghum and sunflower from 1994 to 2003. The effects of this incorporation were assessed on crop yields and soil properties for 10 years together with fertilizer application. Horsegram biomass ranging from 3.03–4.28 t ha^?1 year^?1 (fresh weight) was produced and incorporated in situ under different levels of fertilizer application. Annual incorporation improved the soil properties and fertility status of the soil, which resulted in improved yields of test crops. With biomass incorporation, mean organic carbon content improved by 24% over fallow. Microbial biomass carbon improved by 28% at site I. Long‐term biomass incorporation and fertilizer application resulted in the build‐up of soil nutrients compared with the fallow plots. Application of N and P alone resulted in a negative balance of soil K. A time‐scale analysis of yields showed that incorporation together with fertilizer application maintained a stable yield trend over a 10‐year period in sorghum, whereas fertilizer application alone showed a declining trend. At the end of 10 years of incorporation, the increase in grain yield because of incorporation was 28 and 18%, respectively, in sorghum and sunflower over fallow when no fertilizers were applied to rainy season crops. The incorporation effect was even larger in plots receiving fertilizer. The growing and incorporation of a post‐rainy season legume crop is a low‐cost simple practice that even small and marginal farmers can adopt in semi‐arid regions of the country. Widespread adoption of this practice, at least in alternate years, can restore the productivity of degraded soils and improve crop yields.     

坡耕地不同水土保持措施下的养分平衡和土壤肥力变化

在贵州省罗甸县坡耕地上布置长期定位试验 ,研究几种水土保持措施对作物产量和土壤肥力变化的影响。9年的测试结果表明 ,在旱坡耕地上 ,水土流失是造成坡地地力下降、养分损失 ,的主要原因。未采用水土保持措施的坡地种植 ,因水土流失产生的全氮、全磷、有效钾损失 ,分别占总养分消耗量的 5 3.0 % ,6 7.6 %和 19.0 % ,相当于施入土壤的氮素化肥 ,施入的有机和无机磷素 ,有机质的损失与施入的有机肥中有机质含量相当 ,土壤全氮、有机质和有效钾含量趋于下降 ,全磷维持在较低的水平。采取水土保持措施后 ,这些土壤养分可维持平衡或在土壤中逐步积累 ,试验中的植物篱水保处理 ,9年玉米产量平均增产 8.6 % ,并趋于逐年上升。长期的试验证明 ,采用适宜的水土保持措施可提高地力 ,增加产量 ,实现坡耕地的可持续利用     

“Fallow Band System,” a land management practice for controlling desertification and improving crop production in the Sahel,West Africa. 1. Effectiveness in desertification control and soil fertility improvement

Wind erosion is a major contributor to desertification in the Sahel. Although three effective countermeasures for wind erosion (i.e. ridging, mulching with post-harvest crop residue, and windbreaks) have been proposed, they are not practical for Sahelian farmers. Therefore, we designed a new land management practice, termed the “Fallow Band System,” which can be used for both controlling wind erosion and improving soil fertility and crop production. This method does not impose additional expense and labor requirements on Sahelian farmers who are economically challenged and have limited manpower. The objective of this study was to evaluate the effects of this system on wind-erosion control and soil-fertility improvement. We conducted field experiments at the International Crops Research Institute for the Semi-Arid Tropics West and Central Africa and showed that (i) a fallow band can capture 74% of wind-blown soil particles and 58% of wind-blown coarse organic matter, which suggests that it can effectively control wind erosion, (ii) the amount of soil nutrients available for crops in a former fallow band was increased by the decomposition of trapped soil materials containing considerable amounts of nutrients, and (iii) the amount of soil water available for crops in a former fallow band was increased by the trapped wind-blown soil materials through improvement of rainwater infiltration into surface soil. These results lead to the conclusion that the “Fallow Band System” can be useful for preventing desertification and improving soil fertility in the Sahel, West Africa.     

作物营养从有机肥到化肥的变化与反思

二十世纪前，农业生产主要靠施用有机肥为作物提供营养，维持地力不衰，这一时期一般称为“有机营养”阶段。之后，化肥逐渐取代有机肥，成为作物养分的主要来源，农业生产进入以化肥养分供应为主的“无机营养”阶段。化肥的连续大量施用在作物增产方面发挥了巨大作用，也带来了不少问题，以致近年来出现了怀疑或否定农业生产中施用化肥的思潮。为此，本文回顾了植物营养学科的发展历程和我国化肥使用的历史，指出仅靠施用有机肥、种植豆科作物等传统的营养作物的方式难以满足农业生产对养分的需求，化肥与有机肥配合施用是我国农业发展的正确道路。目前生产中，化肥施用存在不合理和过量问题，有机肥施用方面，主要是集约化养殖业与种植业的不合理布局，存在种养分离，难以农业利用等养分管理问题。同时解决这两个问题，除采取已有的合理施肥技术及方法外，还应改变从植物营养角度只重视氮磷钾等无机养分的供应，拓宽为重视碳、氮、磷及钾等不同元素间的时空平衡关系；以农业生态系统养分资源高效循环利用为核心，采取不同方式实现有机–无机营养的结合，应避免陷入有机与无机营养的争论；从生物地球化学循环角度看待养分利用与管理问题，关注养分在田块、流域及区域尺度的流向及对土壤、水体及大气的影响；将科技与政策等有效结合，提高养分利用效率，减少养分损失，保障我国农业的健康持续发展。     

The influence of parent material on soil fertility degradation in the coastal plain of Tanzania

Differences in the vulnerability of soils to fertility degradation are compared for two major soil groups located in the coastal plain of Tanzania and cropped with sisal (Agave sisalana). Ferralsols derived from intermediate gneiss of Precambrian age and Cambisols developed in Jurassic and Neogene limestones partly covered with Quaternary deposits were selected for comparison. A clear influence of parent material was apparent when soils were continuously cropped with sisal and no fertilizers were applied. Serious soil fertility decline occurs in Ferralsols, but Cambisols are resilient to chemical degradation and the fertility decline in these soils was very limited. The differences in degradation rates are explained by the lower initial fertility and low nutrient reserve of Ferralsols, while the Cambisols had higher initial fertility levels and nutrients removed by the sisal crop are replenished by the weathering of the underlying parent material. Sustainable soil fertility management of Cambisols includes only NPK fertilization, but heavy dressings of lime, organic manures and/or chemical fertilizers are required to improve the fertility status of the Ferralsols and to produce crops in a sustainable manner.     

青海省春油菜区土壤养分状况及施肥策略

【目的】海拔高度、成土母质、气候条件、种植品种、耕作方式和施肥水平等因素对农田土壤肥力产生深刻影响。调查明确青海省春油菜区土壤养分的空间分布现状,有助于制定合理的施肥策略和实现该地区春油菜高产优质以及农业的可持续发展。【方法】2015年在青海省东部的湟中、大通和互助三个春油菜主产县,依据各乡镇油菜种植面积大小,共采集了103个耕层土壤样品。测定土壤主要养分含量,并结合ArcGIS中的Kriging插值法研究春油菜田土壤肥力现状及其空间分布特征。【结果】土壤各养分平均含量分别为有机质26.81 g/kg (中等)、全氮1.97 g/kg (丰富)、速效磷19.03 mg/kg (中等)、速效钾164.27 mg/kg (丰富)、有效铁12.02mg/kg (丰富)、有效锰6.43 mg/kg (中等)、有效铜0.70 mg/kg (中等)、有效锌1.81 mg/kg (中等)、有效硼0.27mg/kg (缺乏)。三县土壤全氮和速效磷含量达到中等水平以上的比例分别为94%和91%。速效钾和有效锌含量区域差异较大,速效钾缺乏及以下比例有23.0%,主要分布在湟中和互助县,有效锌缺乏及以下比例有36.9%,主要分布在互助县;有效硼缺乏及以下比例高达93.2%,主要分布在互助和大通县。【结论】青海省春油菜土壤氮磷钾养分含量整体偏高,相应化肥减量空间较大。大通、互助两县应合理减施氮肥;湟中、大通两县应降低磷肥施用量;针对湟中和互助县的速效钾含量缺乏地区应适当增施钾肥。土壤有效硼除湟中县的部分地区外均缺乏严重,有效锌含量缺乏的土壤主要分布在互助县,针对以上区域应合理增施硼肥和锌肥,防止作物因缺素而限制产量和品质的提高。养分的平衡供应将有利于提高肥料利用率,实现春油菜产业的可持续发展。