Restoration of species-rich grasslands on ex-arable land: Seed addition outweighs soil fertility reduction

A common practice in biodiversity conservation is restoration of former species-rich grassland on ex-arable land. Major constraints for grassland restoration are high soil fertility and limited dispersal ability of plant species to target sites. Usually, studies focus on soil fertility or on methods to introduce plant seeds. However, the question is whether soil fertility reduction is always necessary for getting plant species established on target sites. In a three-year field experiment with ex-arable soil with intensive farming history, we tested single and combined effects of soil fertility reduction and sowing mid-successional plant species on plant community development and soil biological properties. A controlled microcosm study was performed to test short-term effects of soil fertility reduction measures on biomass production of mid-successional species. Soil fertility was manipulated by adding carbon (wood or straw) to incorporate plant-available nutrients into organic matter, or by removing nutrients through top soil removal (TSR). The sown species established successfully and their establishment was independent of carbon amendments. TSR reduced plant biomass, and effectively suppressed arable weeds, however, created a desert-like environment, inhibiting the effectiveness of sowing mid-successional plant species. Adding straw or wood resulted in short-term reduction of plant biomass, suggesting a temporal decrease in plant-available nutrients by microbial immobilisation. Straw and wood addition had little effects on soil biological properties, whereas TSR profoundly reduced numbers of bacteria, fungal biomass and nematode abundance. In conclusion, in ex-arable soils, on a short-term sowing is more effective for grassland restoration than strategies aiming at soil fertility reduction.     

Soil Testing Protocols for Organic Farming—Concept and Approach

In this article the authors discuss the concept of soil testing for organic farming and have identified a number of novel methods for estimation of potentially mineralizable nitrogen (N), microbial biomass nitrogen, speciation of biologically active phosphate fraction, and potassium. More so, modification in lime requirement, and cation balancing—a concept for cationic plant nutrition in organic farming are proposed. The present communication suggests an attribute designated “biological fertility index” combining both chemical and biological attributes for exploring the contribution of microbes toward soil fertility. Furthermore, the present article suggests technical approaches for carrying out research on identification of suitable extractants and their validation for robustness for formulating suitable protocols. Successful development of such soil testing protocol will be helpful to the personnel of state soil testing laboratories and organic certifying agencies presently lacking of such facilities.     

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.     

Quantification and Remediation of Soil Chemical Degradation in Tropical Australia,China and Thailand

Soil and land degradation in the tropics can be identified and described in terms of physical, chemical,and biological changes from its pristine state brought about by natural and anthropogenic influences. Acharacteristic of these ecosystems is their capacity to recycle nutrients through soil organic matter (SOM).Following disturbance through changed land management, SOM is rapidly mineralized and there is a cor-responding decline in fertility and the variable charge component of the cation exchange capacity. As theseecosystems are strongly dependent on SOM for their functionality, changed land use can have irreversible im-pacts on the productivity of these systems. The paper focuses on quantifying chemical degradation throughprinting. Using values taken from the fingerprint of an undisturbed soil, an index of chemical degradationimprove poor quality soils in their natural condition are discussed, such as the addition of natural clays andsilicated materials. Results are present to show the effect of each of the aforementioned strategies on surfacecharge characteristics and associated increases in plant productivity.     

Agricultural suitability of degraded Acrisols and Lixisols of former tea lands in Sri Lanka

Physical and chemical soil degradation hinder the introduction of mixed cropping systems on former tea lands in the Central Highlands of Sri Lanka. For instance on two typical soil catenas soil properties such as texture, pH, acidity parameters, pedogenic oxides and available plant nutrients indicating fertility are presented. Obviously Al³⁺ occupies a larger part of the exchange complex and accounts for more soil acidity than H⁺. Al toxicity is hence a major restricting factor for plant growth in the area. The investigated data also permit an evaluation of soil erodibility and a soil fertility assessment according to the Fertility Capability Classification System (Sanchez et al., 1982). Agricultural measures to reduce soil acidity and cover the lime requirements of the soils are advised. Additional soil conservation measures should diminish soil erosion in order to improve the sustainability of the cropping systems.     

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。     

Soil fertility in organic farming systems – fundamentally different?

Abstract. Soil fertility is defined as the ability of a soil to provide the conditions required for plant growth. It is a result of the physical, chemical and biological processes that act together to provide nutrients, water, aeration and stability to the plant, as well as freedom from any substances that may inhibit growth. Within this definition, it is useful to distinguish between those components of fertility which change relatively slowly, perhaps over the course of a rotation, or in some cases, decades, and the more immediate contribution from materials such as fertilizers and manures. The term 'inherent fertility' is used to describe these more stable characteristics, while recognising that they are, to a large extent, products of soil management. We conclude that, although nutrient management in organically managed soils is fundamentally different to soils managed conventionally, the underlying processes supporting soil fertility are not. The same nutrient cycling processes operate in organically farmed soils as those that are farmed conventionally although their relative importance and rates may differ. Nutrient pools in organically farmed soils are also essentially the same as in conventionally managed soils but, in the absence of regular fertilizer inputs, nutrient reserves in less-available pools will be of greater significance.     

Arbuscular mycorrhizal fungi and nematodes are involved in negative feedback on a dual culture of alfalfa and Russian wildrye

The complex biological interactions taking place in soil–plant systems may sometimes alter the functioning of an ecosystem. We examined the relationship between arbuscular mycorrhizal (AM) root colonization, nematode populations, and plant competition in an 8-year-old field experiment comparing alfalfa monoculture to dual culture of alfalfa (Medicago sativa L.) and Russian wildrye (Psathyostachys juncea Fisch. Nevski) (RWR) grown under different soil P fertility levels, in a Brown Chernozemic soil in Saskatchewan. The experiment included three P rates: 0, 20 and 40 kg P₂O₅ ha⁻¹ (0P, 20P and 40P) applied annually and was sampled three times during the cropping season: 30 June, 1 September and 30 September. Higher AM symbiotic development compensated for reduced soil P fertility in alfalfa stands without RWR and forage dry matter yield was not affected by P rates. But in the presence of RWR, reduced soil P fertility at 0P and 20P led to forage yield reduction. Fertilization treatments modified the soil microbial community structure only in the presence of RWR, as revealed by discriminant analysis of the profiles of microbial phospholipids fatty acid in soil lipid extracts and functional nematode groups. Arbuscular mycorrhizal root colonization level was reduced with P fertilizer both in the presence and absence of RWR. In the presence of RWR, lower plant AM root colonization was concurrent with higher abundance of total, fungivorous and omnivorous nematodes. Our results are consistent with a model of negative feedback from the plant-associated soil microflora where the presence of RWR increased the population of fungivorous nematodes and grazing of AM hyphae. Negative impacts were larger in low P fertility soils promoting AM symbiotic development. The unexpected decrease in alfalfa–RWR dual culture yield under 0P and 20P fertilization levels was attributed to a carbon drain created by enhanced nematode feeding on AM fungi in the presence of RWR.     

Poultry litter and tillage influences on corn production and soil nutrients in a Kentucky silt loam soil

Broiler chicken (Gallus gallus) manure, a rich source of plant nutrients, is generated in large quantities in southeastern USA where many row crops, such as corn (Zea mays L.), are also extensively grown. However, the use of broiler manure as an economical alternative source of nutrients for corn production has not been extensively explored in this region. This study was conducted to examine the use of broiler litter as a source of nutrients for corn production, as influenced by tillage and litter rate, and any residual effects following application. In addition, the consequence of litter application to soil test nutrient levels, particularly P, Zn and Cu, was explored. The treatments consisted of two rates of broiler litter application, 11 and 22 Mg ha⁻¹ on a wet weight basis, and one rate of chemical fertilizer applied under no-till and conventional tillage systems. Treatments were replicated three times in a randomized complete block design. Corn was grown with broiler litter and inorganic fertilizer applied to the same plots each year from 1998 to 2001. In 2002 and 2003, corn was planted no-till, but only N fertilizer was applied in order to make use of other residual litter nutrients. Soil samples were taken yearly in the spring prior to litter application and 4 years after the cessation of litter application to evaluate the status of the residual nutrients in soil. Two years out of the 4-year experiment, broiler litter application produced significantly greater corn grain yield than equivalent chemical fertilizer application and produced similar grain yield in the other 2 years. Corn grain yield was significantly greater under no-till in 1999, but significantly greater under conventional-till in 2000, and no difference between the two tillage systems were observed in 1998 and 2001. With 4 years of litter application, Mehlich-3 P increased from an initial 18 mg kg⁻¹ to 156 mg kg⁻¹ with 11 Mg ha⁻¹ litter and to 257 mg kg⁻¹ with 22 Mg ha⁻¹ litter. For every 6 kg ha⁻¹ of P applied in poultry litter Mehlich-3 P was increased by 1 mg kg⁻¹. Modest increases in Mehlich-3 Cu and Zn did not result in phytotoxic levels. This study indicated that an optimum rate of broiler litter as a primary fertilizer at 11 Mg ha⁻¹ applied in 4 consecutive years on a silt loam soil produced corn grain yields similar to chemical fertilizer under both no-till and conventional tillage systems and kept soil test P, Cu and Zn levels below values considered to be harmful to surface water quality or the crop.     

Response of common bean,upland rice,corn, wheat,and soybean to soil fertility of an Oxisol

Plant nutrient deficiencies are the main yield‐limiting factors in highly weathered acid soils around the world. Five greenhouse experiments were conducted on an Oxisol to identify nutrient deficiencies in common bean, upland rice, corn, wheat, and soybean. The treatments consisted of 13 fertility levels including an adequate level and remaining without application of one of the essential plant macro‐ or micronutrients. Dry matter yield of tops of all the crop species was affected by fertility treatments; however, significant effects of treatments were obtained in the case of common bean, upland rice, and corn. Based on tops dry weight under different treatments compared to adequate fertility level (AFL), the most yield‐limiting nutrients were in the order of phosphorus (P) > calcium (Ca) > magnesium (Mg) > boron (B) > zinc (Zn) for common bean, P > molybdenum (Mo) for upland rice, and P for corn. For the wheat crop, there was substantial decrease in tops dry weight in the absence of Ca, P, and potassium (K) nutrients. In the case of soybean, substantial tops dry weight reduction was due to deficiency in the order of P >Ca>Zn.     

澳大利亚、中国和泰国的热带地区的土壤化学退化的量化及修复

Soil and land degradation in the tropics can be identified and described in terms of physical,chemical,and biological changes from its pristine state brought about by natural and anthropogenic influences.A characteristic of these ecosystems is their capacity to recycle nutrients through soil organic matter(SOM). Following disturbance through changed land management.SOM is rapidly mineralized and there is a cor responding decline in fertility and the variable charge component of the cation exchange capacity.As these ecosystems are strongly dependent on SOM for their functionality,changed land use can have irreversible impacts on the productivity of these systems.The paper focuses on quantifying chemical degradation throughbenchmaking using data from paried sites in tropical China and Thailand using surface charge finger printing.Using values taken from the fingerprint of an undistubed soil,an index of chemical degradation from ideality was calculated.Various management stratgeies that attempt to reverse degradative trends or improve poor quality soils in their natural condition are discussed.such as the ddition of natural clays and silicated materials.Results are present to whow the effect of each of the aforementional strategies on surface charge characteristics and associated increases in plant productivity.     

Performance of biochar derived from Cymbopogon winterianus waste at two temperatures on soil properties and growth of Bacopa monneri

ABSTRACT

The present study aimed to evaluate the effect of biochar derived from the distilled waste of Cymbopogon winterianus at two different pyrolysis temperatures (450°C and 850°C) on the chemical and biological properties of sandy loamy soil (SLS) and its subsequent impact on plant growth. Pot experiments utilizing Bacopa monnieri were performed in a greenhouse with four different application rates of biochar (2%, 4%, 6%, and 8% (w/w)) for 120 days. Biochar induced alterations in soil properties (nutrients, enzymes, and microbes) and plant responses (yield, biocide and antioxidant content) to biochar addition were measured. Biochar application, notably improved the soil carbon, cation exchange capacity, and the availability of NH₄ ⁺ and phosphorus. Initially, biochar produced at the lower temperature had more effect on the available nitrogen, phosphorus, soil enzymatic properties, and plant biomass growth. After 120 days, the pyrolysis temperature had only a marginal influence on biochar-induced effects on soil pH, WHC, and soil enzymatic activities. Our results suggest that C. winterianus derived biochar amendment leads to an overall amelioration of soil fertility and plant growth improvement. In specific biochar produced at lower temperatures (450°C) was more effective for improvement of plant biomass and soil characteristics.     

Plant growth and microbial activity in a tropical soil amended with faecal pellets from millipedes and woodlice

The effect of soil fauna-mediated leaf litter (faecal pellets) versus mechanically fragmented (finely ground) leaf litter on biomass production of rice (Oryza sativa, var. Primavera) was assessed in pot tests. Rice seedlings were either grown in soil samples amended with faecal pellets of diplopods and isopods fed on leaf litter of a legume cover crop (Pueraria phaseoloides (Roxb.) Benth) and a peach palm (Bactris gasipaes) or in soil amended with finely ground leaf litter. The addition of faecal pellets caused a significant and dose-related increase in plant biomass compared to pure soil. Ground leaf litter induced a significantly smaller positive effect on plant biomass development with Pueraria litter > Bactris litter > mixed primary forest litter. In contrast, soil microbial biomass development during the 4 weeks plant test was higher in the soil amended with ground litter as compared to soil amended with feacal pellets. The results show a clear positive effect of the soil fauna on soil fertility and indicate differences in the availability of nutrients from the organic substrates to higher plants and soil microorganisms.     

Effect of soil fertility and maturity stages at harvest on maize yield under rain-fed conditions

Understanding critical management practices during seed development would help to improved crop production as climate patterns change. This study focused on the interactive effect of soil fertility with harvesting stages, on hybrid maize yield under two different agro-ecological locations during the 2014/2015 and 2015/2016 summer seasons in KwaZulu-Natal, South Africa. The 2015/2016 season was drier than that of 2014/2015. The field trials were split plots design, where varying fertility levels (main plot) and harvesting stages (sub plots) were replicated four times. The interaction was determined by variables of plant growth, physiology and yield parameters. The plant growth and physiological parameters measured were significantly influenced (P < 0.001) by the interaction of fertility levels across days after planting and silking. The interactions of soil fertility levels with harvesting stages had significant effects (P < 0.05) on all yield components during the wetter 2014/2015 season, as well as on seed yield, harvest index, thousand seed weight and total biomass in the drier 2015/2016 season. Optimal fertilization improved maize yield at each stage of harvesting. This study showed that harvesting stress-free optimally-fertilized maize at dent stage maximized yield potential than allowing it to reach physiological maturity under stressful conditions.     

Do Compost and Vermicompost Improve Macronutrient Retention and Plant Growth in Degraded Tropical Soils?

Soil degradation and water pollution are widespread land degradation problems in Southeast Asia. Policy makers are currently faced with the challenge of designing and implementing strategies to maintain soil fertility and avoid off-site effects. The aim of this study was to determine the effect of organic substrate amendments on soil properties, nutrient leaching and the growth of Ipomea aquatica in an acidic degraded soil from northern Vietnam. Plants were grown in an Acrisol in buckets under natural weather conditions for two months. The same amount of nutrients was applied either in a purely synthetic form (mineral fertilizers) or as two alternative organic substrates (three month old compost or vermicompost from buffalo dung) plus additional amounts of synthetic mineral nutrients to ensure the same quantity of NPK. The influence of these respective substrates on the soil's physical and chemical properties as well as plant growth was examined. Both compost and vermicompost led to an improvement in soil properties with an increase in the pH, soil organic matter and nutrient content, compared to soil fertilized with synthetic mineral products. The highest plant productivity was obtained with vermicompost and synthetic fertilizers, with no significant difference between these two treatments. Chemical fertilization, however, is the least effective practice based on the amount of nutrients leached from the soil (about 38% of N and 22% of K, compared to less than 10 and 5% of N and K with organic amendments). P leaching was not influenced by the fertilizer treatments. In conclusion, vermicompost does appear to be a relevant alternative to chemical fertilizers because it leads to similar enhancements in plant growth, at the same time as increasing soil quality and decreasing nutrient leaching.     

环渤海低平原农田生态系统养分循环与平衡研究

了解农田养分输入、输出和平衡状况,以及土壤肥力现状与变化特征,对实现养分资源优化管理、地力的持续提升、肥料利用率提高和农业可持续发展具有重要意义。基于1985年、2000年和2014年河北省南皮县国民经济统计资料,分析了从1985年到2014年县域农田生态系统养分循环与平衡状况;利用1981年第2次土壤普查和2015年实测南皮县域土壤耕层养分含量数据,探讨了耕层土壤养分变化及空间分布格局特征。结果表明,1985—2014年南皮县农田养分输入输出均呈持续上升趋势, NPK养分输入由10701 t增加至23386 t,年递增率2.33%; NPK养分来源结构略有不同, NP来源以化肥为主,其次是人畜粪尿和作物秸秆有机肥源;而K素来源主要是有机肥源。农田养分输出以作物吸收为主,占养分总输出的80%以上, NPK总输出由1985年的9093 t增加到2014年的18846 t,年均增速2.17%。从养分表观平衡的角度看,从1985年到2014年NP始终有大量盈余, P素盈余大于N素, N和P表观平衡率分别为16.8%~34.2%和26.9%~65.5%;若考虑有机氮的有效性问题,1985—2000—2014年3个时段有效氮盈亏率依次为18.1%、6.5%和-7.8%,有效氮平衡由盈余转向亏缺;而K素经历了由赤字逐渐向盈余的转变过程,由1985年的-33.5%赤字发展至2014年的33.6%盈余。受农田养分平衡状况的影响,南皮县土壤有机质、全氮、有效磷发生了显著变化,1981—2015年有机质由8.62 g·kg-1增至14.0 g·kg-1,增幅62.4%;全氮由0.542 g·kg-1增至0.908 g·kg-1,增幅67.5%;有效磷由2.0 mg·kg-1增加到20.8 mg·kg-1,增加了9.4倍。而碱解氮和有效钾变化不明显,分别由70.5 mg·kg-1和141 mg·kg-1增加到71.8 mg·kg-1和147 mg·kg-1,相对增幅仅为1.8%和4.2%。建议今后南皮县在农业生产中大力推广科学施肥技术,重视有机肥和化肥配施,推广秸秆还田,通过改进施肥方法提高肥料利用效率;养分管理中应提倡“稳氮、控磷、补钾”的施肥对策,避免过多的盈余养分进入环境。     

Effects of crop growth and soil treatments on microbial C,N, and P in dry tropical arable land

We studied the dynamics of microbial C, N, and P in soil cropped with rice (Oryza sativa) and lentils (Lens culinaris) in a dryland farming system. The crop biomass and grain yield were also studied. The microbial biomass and its N and P contents were larger under the lentil than under the rice crop. Microbial nutrients decreased as the crops grew and then increased again. Farmyard manure and NPK fertilizer applications increased the level of microbial nutrients, crop biomass, and grain yield by 35–80%, 55–85%, and 74–86%, respectively. However, these applications had no significant effect on most of the soil physicochemical properties in the short term. The microbial biomass was correlated with the crop biomass and grain yield. The calculated flux of N and P through the microbial biomass ranged from 30–45 and 10–19 kg ha^-1 year^-1, respectively. Cultivation of a cereal crop followed by a leguminous crop sustains higher levels of microbial nutrients and hence greater fertility in impoverished tropical arable soils. The soil microbial biomass appears to contribute significantly to crop productivity by releasing nutrients, and applications of manure, either alone or with fertilizers, promote this effect more strongly than the application of NPK fertilizers alone.     

A winter intercrop of faba bean and rapeseed for silage as a substitute for Italian ryegrass in rotation with maize

In order to combine the ability of legumes to fix atmospheric nitrogen and the cruciferous capacities to mobilize soil nutrients and herbicide action, the aim of this work was to evaluate an alternative winter intercrop (faba bean-rapeseed) as a replacement of Italian ryegrass culture in a rotational system with maize as summer crop. For this purpose, two adjacent plots were used during three agronomic years (2011–2012, 2012–2013 and 2013–2014) to evaluate the agronomic performance through the forage production, nutritional composition of forage and silage, and the effects on soil fertility. The Italian ryegrass was cultivated under conventional management: using chemical fertilization and recommended dosages of herbicides. The faba bean-rapeseed intercrop was cultivated under an alternative management: organic fertilization and less herbicide supply. The intercrop provides higher forage yield per hectare than Italian ryegrass, with greater protein (kg ha^?1) and similar energy (GJ ha^?1) yields. The intercrop allows reducing the inputs of chemical fertilization and herbicides, and it has a positive effect on the balance of soil nutrients, especially increasing the potassium, calcium and magnesium contents. The results show that faba bean-rapeseed intercrop could be an alternative to the Italian ryegrass as winter crop.     

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。     

耕地地力对化肥养分利用的影响机制及其调控研究进展

耕地地力影响了化肥养分的利用效率,是调控养分利用率的基础途径。本文概述了耕地土壤障碍对养分利用的制约机制、耕地地力培育对养分利用的促进机制、提高养分资源利用效率的耕地培肥模式3个方面的研究进展。针对我国主要的耕地土壤–作物系统,提高化肥养分利用率需要解决4个地力调控方面的关键问题:地力与养分利用率关系及其时空变化规律、土壤障碍制约养分高效蓄积转化机制与消减原理、地力培肥促进根系–土壤–微生物互作提高养分耦合利用机制及调控途径、肥沃耕层构建与生物功能提升对养分蓄纳供应的协同驱动增效机制与调控理论。本文提出基于多时空尺度综合研究,建立稳定提升土壤功能–加速养分循环利用的"双核驱动"地力综合管理理论,在不同区域构建并应用化肥减施增效的耕地地力综合管理模式,实现耕地大面积均衡减施化肥的目标。