Fertilizer Use and Wheat Yield in Central and Eastern European Countries from 1986 to 2005 and Its Implication for Developing Sustainable Fertilizer Management Practices

Economic and political challenges impact agricultural practices, production efficiency, and crop yields. We hypothesize that increased conversion efficiency of fertilizer to crop yield resulted from changes in fertilizer management in Central and Eastern European countries. Efficient nutrient management depends on fertilizer applied, management practices, and weather, which impact uptake, utilization efficiency, and crop yield. Trends in fertilizer consumption and wheat yields from 1986 to 2005 were studied for five countries. There were significant differences in yield gap, defined as the difference between potential and actual yields. Partial factor productivity of applied nitrogen fertilizer (N) is calculated from real and modified indices. A predictive metric is introduced based on the quantity of unworked, or nonproductive, N (N_uw). Sustainable cropping practices reduce N_uw and yield gap. Improved knowledge of crop responses to balanced plant nutrition at the country level contribute to improved agricultural and environmental policies and enhance production sustainability.     

Effect of nitrogen and potassium fertilizer on growth,herbage and oil yield of irrigated palmarosa (Cymbopogon martinii [roxb.] wats. var. motia burk) in a semi-arid tropical climate

The world's agricultural production is increasing by 1 to 2 per cent annually and has been enough to satisfy the growing world population's need for food. Breeding, fertilisation and crop protection have decidedly contributed to that progress in productivity. But since the 1960s, agriculture has been more and more conceived by the public as an environment-contaminating industry. The public is concerned about water contamination with nitrate as a result of the use of fertilisers, and about harmful effects of chemical plant protection products on soil, water, air, animals and wild plants. The public discussion has not remained without consequences. Sustainability of development has become a central political objective in all spheres of social life, and in all world regions. Sustainable development concerns economic, ecological as well as social objectives, and is also the guideline for a renovation of agriculture. Any concepts and strategies integrating environmental aspects into agricultural production are linked with the objective of sustainable development. Discussion on sustainable agriculture has become more concrete on the basis of the Brundtland Report and Agenda 21 , as well as the various follow-up meetings of the 1992 Conference of Rio. Although efforts towards sustainable development in agriculture encounter widespread scepticism, clear progress is to be noted since that discussion has intensified. Farmers have paid more attention to new farming practices. Environmental aspects now play an important role when extension services advise farmers on fertilisation and crop protection. Research has contributed essentially to the change in agriculture towards sustainable production. Sustainability in agriculture has also been expressed in new legal regulations. Principles of good professional practice in applying fertilisers, as it is required by the Fertilisers Act from the year 1989, have been spelled out more clearly in a legal regulation issued on 26 January 1996 (Federal Law Gazette part I of 06 February 1996, p. 118). Principles of good professional practice in crop protection were published in Bundesanzeiger (Federal Gazette) No. 220 a of 21 November 1998. Principles of integrated crop protection were first discussed by representatives of agriculture, environment protection offices and researchers at a workshop at Biologische Bundesanstalt für Land- und Forstwirtschaft (BBA, Federal Biological Research Centre for Agriculture and Forestry) in Kleinmachnow on 23° March 2000. The debate on sustainability centres around the aspects of economic and social efficiency of measures taken, and their effects on the environment. The following article deals with some basic aspects of efficiency on the one hand, and effects/emission on the environment on the other, of fertilisers and crop protection products as important input factors in agriculture. Crop husbandry always is an interference with nature. The Lüneburger Heide cropping region is a memorial of ecologically out-dated land management. Today, sustainable and at the same time efficient agriculture can only be realised with modern methods based on sound knowledge. This includes mineral fertilisation and chemical crop protection. Cropping permanently draws nutrients from the soil-plant system. They have to be refilled by fertilisation. If no fertilising measures are taken at all, the humus layer of the soil declines and soil degrades. The decline in fertility will result in yield losses of between 70 and 90%. In contrast, combination of organic and mineral fertilisers has continually added to soil fertility. This is reflected in the humus content of the soil, which is by about a quarter higher than it was a hundred years ago. Farmers resorting solely to mineral fertilisation produce yields lower by 5-10% than those combining mineral and organic fertilisers. If only organic fertilisers are used, this may reduce yields by between 10 and 40%, depending on the site. Unwanted side-effects of fertilisation (such as leaching of nitrates) may be reduced to a tolerable level by precise input of nutrients, improved methods such as precise fertiliser input depending on the condition of certain field patches, and by integrated crop protection, which relies on synergetic effects of various measures. Germany has for these reasons witnessed a relaxation of environmental pressure from excessive nutrient input. If crop protection measures were abandoned, pests and diseases would reduce yields by between 40 and 80 per cent. Our own trials about energy input-output proportions have shown a ratio of 1:4.6 with use of fertilisers (100kg N/ha), and a ratio of 1:8.6 with use of fertiliser and chemical plant protection products. The risk potential of modern chemical plant protection products has permanently decreased over the past few decades and is generally about one tenth of the values of 15 years ago. Integrated crop protection, which combines various methods of crop protection and reduces the use of chemical crop protection products to a necessary minimum, is the "optimal solution for the future" and "contributes to the sustainability of agriculture", as it is said in the Agenda 21 programme adopted by the 1992 environmental conference in Rio.     

The leaching potential as a land quality of two Dutch soils under current and potential management conditions

Within the field of land evaluation, crop productivity as well as environmental effects should be investigated for specific land use types. The leaching potential is introduced as an environmental land quality and is expressed in terms of a downward flux from the root zone. The frequency distribution and the amount of this downward flux were calculated for each period of the year using the SWANY model, which simulates soil water flow, evapotranspiration and crop growth. Two examples for the use of this land quality are presented for potato production under different irrigation regimes on a coarse-textured Humic Podzol and under different groundwater control regimes on a median-textured Calcaric Fluvisol in the Netherlands.

The simulation results showed that irrigation increases crop yields for the Humic Podzol, but also increases the leaching potential. Restricted irrigation resulted in similar crop production levels, but in only part of the additional downward flux from the root zone. For the Calcaric Fluvisol, drainage provided higher crop yields and a slightly lower leaching potential due to an increase in crop uptake.     

开发更高效的生物炭肥料提高辣椒产量和质量

Utilization of biochar at high application rates can increase soil C and crop yields, decrease greenhouse gas emissions and reduce nutrient run-off from soils. However, the high application rate of 10 t ha-1may not return a profit to the farmer due to the high cost of biochar. In this study biochar was modified through pre-treating the biomass and post-treating with phosphoric acid, minerals and different chemical fertilisers to study the effects of two new enhanced biochar fertilisers on the yield and quality of green pepper in a field experiment with 5 fertilisation treatments and 3 replications. The two new biochar fertilisers significantly(P 0.05) increased the yield of green pepper(11.33–11.47 t ha-1), compared with the conventional chemical fertiliser(9.72 t ha-1). The biochar fertiliser treatments improved the vitamin C content of green pepper from 236.99 to 278.28 mg kg-1, and also significantly(P 0.05) reduced the nitrate content from 132.32 to 101.92 mg kg-1, compared with chemical fertiliser. This study indicated that, compared to the use of conventional chemical fertiliser, all of the biochar fertiliser treatments could significantly improve the yield and quality of green pepper.     

Actual and potential yield for rainfed and irrigated wheat in China

The parametric water use and crop yield model (YIELD) was applied to China and Korea in order to examine the responses of potential and actual winter wheat yield parameters necessary for optimal crop production in that region. A network of 241 stations provided the seasonal climatic input, consisting of data averaged over approximately a 20 year period. Among the results, highest annual yields under full irrigation occurred in the Yangtze River area, Yunnan—Szechwan—eastern Tibet, Korea and the northeast, and the upper Huang Ho River. Lowest yields were calculated for the northwestern interior. High annual yields exceeded 5–6,000 kg ha^?1. Under rainfed-only conditions, the management efficiency of wheat production was higher in many regions than cases with full irrigation. In order to achieve optimum crop yields, about 400 mm of irrigation water was needed in the northwest, contrasted with none required in the south and east of China. A sensitivity analysis was applied to determine the degree of error introduced by faulty, uncertain, or missing environmental input data for the stations utilized in this study.     

基于LCA的不同间作体系产量优势及温室效应研究

为了探究间作体系对农田生态系统温室效应和产量优势的影响,本文选用小麦/蚕豆和玉米/马铃薯间作种植体系,通过为期2年的田间小区试验,采用生命周期评价法(LCA),以小麦/蚕豆间作和小麦单作、玉米/马铃薯间作和玉米单作为研究对象,以生产1 000kg作物为评价的功能单元,建立农资系统和农作系统生命周期资源消耗以及温室气体排放清单,研究了不同种植体系的作物产量、全球增温潜势和能源消耗等指标的差异。结果表明:与单作小麦相比,间作小麦两年的产量分别增加18.04%和39.94%;与单作玉米相比,间作玉米的产量分别增加2.65%和23.16%;小麦/蚕豆间作系统两年平均增幅高于玉米/马铃薯间作系统。小麦/蚕豆间作的土地当量比两年均大于1,玉米/马铃薯间作的土地当量比仅有1年大于1。与单作小麦相比,两年间作小麦的全球变暖潜值分别降低15.28%和28.53%,能源消耗分别减少15.29%和28.53%;与单作玉米相比,间作玉米的全球变暖潜值分别降低2.61%和19.05%,能源消耗分别减少2.61%和18.83%。小麦/蚕豆间作的间作产量优势优于玉米/马铃薯,但玉米/马铃薯间作的增温潜势低于小麦/蚕豆间作。合理间作具有显著增产效应,同时可以降低温室效应以及能源消耗,以更低环境代价获得作物高产高效。     

A review of tillage methods and soil and water conservation in southern Africa

Population pressures within southern Africa are forcing people to increasingly crop land of a diverse and fragile nature where the risk of environmental degradation is high and current yields are low. Much of the earlier tillage research is not applicable to these conditions as efforts have concentrated on commercial farming with tractors for the higher potential regions. It is only in the last 10–20 years that attention has increasingly focused on the tillage requirements of small-scale farmers in these harsh water-scarce semi-arid regions. There is now a clearer understanding of the basic environmental constraints to crop production in terms of climate, poor soil fertility and structure and considerable advances have been made towards improved systems but there is still a lack of appropriate tillage system recommendations. All too frequently researchers have omitted the farmer input from their considerations and endeavours. Consequently limited consideration has been given to the social (e.g. land tenure), economic (e.g. credit), energy (labour and draught power) and technical constraints experienced by the small farmers they are trying to help.

The need to develop more adoptable interim systems is therefore indicated but the slim margins within which small farmers must operate highlight the continuing need for sound tillage research to backstop the development of sustainable conservation systems.     

以粪污水热资源化为核心的高效种养结合系统分析与展望

种养结合系统是实现养殖业和种植业可持续发展的重要途径。水热技术可以转化畜禽粪污生产生物原油、生物炭、水相产物和气体产物,分别具有燃料、土壤改良、农用杀菌剂和温室气体肥料应用潜力,以粪污水热资源化为核心构建的高效种养结合系统有助于提高土地对畜禽粪污的消纳能力、构建生态可持续的绿色循环农业,实现畜禽粪污资源化利用、种植业和养殖的协同高效发展。该研究基于国内外近十余年的研究,系统综述了粪污水热资源化产物在种养结合生态循环农业模式中的作用和应用潜力,论述了畜禽粪污水热转化生物原油在农业内燃机中作为燃料的研究现状,阐述了水相产物作为潜在的农用杀菌剂在作物病害防控中的作用,梳理了畜禽粪污来源水热炭在转化机理、理化特性和还田应用中的研究进展,分析了气相产物中的组分和用于温室种植的潜力。在此基础上总结了以粪污水热资源化为核心的高效种养结合系统面临的主要挑战,并对水热资源化产物农业循环应用的研究方向进行展望。研究为畜禽粪污水热资源化产物的高值利用和高效种养结合系统研究提供理论参考。     

基于作物及遥感同化模型的小麦产量估测

为提高陕西省关中平原冬小麦的估产精度,该文通过粒子滤波算法同化Landsat遥感数据反演的状态量叶面积指数(leaf area index,LAI)、土壤含水量(0~20 cm)、地上干生物量数据和CERES-Wheat模型模拟的状态量数据,分析小麦不同生育期的LAI、土壤含水量及生物量同化值和实测单产的线性相关性,以构建同化估产模型。结果表明,在返青期土壤含水量同化值和实测单产的相关性高于LAI、生物量同化值和实测单产的相关性,选择土壤含水量作为最优变量;在拔节期和抽穗-灌浆期同时选择LAI、土壤含水量及生物量作为最优变量;在乳熟期选择生物量作为最优变量。在小麦各生育时期同化最优变量的估产精度(R2=0.85)高于同时同化LAI、土壤含水量及生物量的估产精度,同时同化LAI、土壤含水量及生物量的估产精度高于同时同化LAI和土壤含水量(或LAI和地上干生物量、或土壤含水量和地上干生物量)的估产精度,表明在作物不同生育时期同化与产量相关性较大的变量对提高估产精度有重要作用。     

Constraints for potato production in the tropics

Potato tuber yields in the tropics are extremely low compared to those of temperate zones. The low yields merely reflect the inability of the current technology to overcome soil and environmental constraints. Given the various constraints affecting potato production in the tropics, few viable soil and crop management options remain. This paper reviews key constraints for potato production, assesses the impact of indigenous and/or adapted technology in managing them, and examines basic relationships describing productivity changes as management takes place. The overall intent of this paper is to outline the scientific basis for developing management strategies to sustain and improve potato production in the tropics.     

A simple model of potato growth and yield: Part II. Validation and external sensitivity

A model has been developed which calculates the dates of 50% emergence and of canopy closure in the potato crop and which estimates total dry matter production and yield. The output from the model has been tested against three sets of independent data, one to test the estimation of dates of emergence and canopy closure, a second to examine the sequence of dry matter accumulation and the third to test estimates of total yield. This validation exercise has shown the model to be successful in its aims of providing an estimate of potential yield of a potato crop using only simple inputs and of describing the development of the crop towards that yield. The limitations of the model have been identified and possible developments have been discussed.The sensitivity of the potential yield to changes in times of planting and harvest and to a range of real combinations of weather has been examined to show the possible consequences of altered farm practice and the year-to-year fluctuations in temperature and radiation receipt.The use of the model in the analysis of shortfalls in farm yields has been discussed.     

Long-term energy use and economic evaluation of three tillage systems for cereal and legume production in central Spain

Three different experiments have been carried out in the area to the northeast of Madrid (central Spain) over 10 years with winter wheat (Triticum aestivum L.), winter barley (Hordeum vulgare L.), spring barley and vetch (Vicia sativa L.) grown for hay. In these experiments, three tillage systems were compared: conventional tillage (primary tillage was mouldboard ploughing to 300 mm depth), minimum tillage (primary tillage was spring tine cultivation either with a chisel or a cultivator to 150 mm depth) and zero tillage (direct drilling), in relation to energy consumption, production costs, energy efficiency and productivity, and economic returns. The experiments were performed on a Vertic Haploxeralf of a clay loam texture.The aforementioned variables were calculated considering every input (i.e. fertilisers, seeds, herbicides, machinery and fuel) including all the labour practices performed to harvesting. Post-harvesting activities were not included.The results showed that important energy and production cost savings may be achieved through minimum tillage and zero tillage, compared with conventional tillage. These energy savings ranged from 7 to 11% for cereal crops, whereas for vetch crops the reduction was 10% for minimum tillage and 15% for zero tillage. Production costs for minimum tillage were 13–24% less than for conventional tillage. For zero tillage these reductions ranged from 6 to 17%. For cereal crops, minimum tillage and zero tillage had energy productivities which were 18% and 20%, respectively, greater than that for conventional tillage. In most cases, yields of winter crops were similar, regardless of the tillage system considered. Only spring barley showed lower yields with zero tillage. For winter cereals the profitability with minimum tillage and zero tillage is higher than that with conventional tillage. However, spring barley is less profitable when using zero tillage.     

Evaluation of a model for predicting sucrose yields following hurricane damage to sugarcane in Hawaii

A census taken within 3 months after Hurricane Iwa struck the island of Kauai in November 1982 provided data for a model of growth and production from which to calculate an estimated percent yield loss due to the hurricane. The estimated percentage loss was then subtracted from the potential yield projected from a linear regression of the five preceding years to give a modeled yield estimate. The model-estimated yields and the projection-estimated yields of two hurricane-struck plantations for the two years following the hurricane were compared to the actual yields reported by their sugar mills. For the individual plantations over the two years the modeled yields ranged from 0.3% under to 28.4% over the actual yields.The model gave yield estimates closer to the actual recorded yields than did the projected yield estimates, and it was more accurate the first year than the second year following the hurricane. Additionally, the model was more accurate for the rain-fed plantation than for the irrigated-plantation. Thus, the model tested here for evaluating sugarcane yields in response to hurricane damage varied in accuracy by location and year. Nevertheless, the model provides a method to derive quantitative estimates of natural hazards on crop production and is a valuable tool.     

保温时间与粒度对稻秆和棉秆热解产物组成及能量转化影响

热解炭化技术的开发对秸秆的能源化利用具有重要意义。试验研究了保温时间与粒度对水稻和棉花秸秆热解产物理化特性及能源转化的影响。结果表明,保温时间从0到120 min中,秸秆生物炭产率先降低后略增加,热解气中CH_4、C_nH_m和H_2百分含量增加,其高位热值和能量转化率增加,而生物炭的pH值、电导率、灰分、固定碳、C、高位热值增加,保温时间为90 min的生物炭的炭化程度最好。秸秆中能量有1.5%~5.4%保留在热解气中,有50%~57%保留在生物炭中。不同粒度相比,粗粉秸秆的生物炭的炭产率、挥发分、H、O、N及碳转化率最高,细粉秸秆热解气中CO和CH_4百分含量、高位热值和能量转化率最高,而超微秸秆生物炭的pH值、灰分、C最高。棉花秸秆生物炭的挥发分、固定碳、C、H、碳转化率、高位热值和能量转化率高于水稻秸秆生物炭。     

Plant Growth Retardants,Plant Nutrients,and Cotton Production

Soil fertility and crop management are the two most important factors of modern agricultural activity. Managing the balance of vegetative and reproductive growth is the essence of managing a cotton crop. It is well known from numerous fertilizer experiments that the yield of agricultural crops has been strongly dependent on the supply of mineral nutrients, which have been used in crop cultivation to exploit the full genetic potential of the plant. Supplying optimal quantities of mineral nutrients to growing crop plants is one way to improve crop yields. In recent years, several approaches have been tried to break this yield plateau, and among them is application of plant growth regulators (PGRs). In maximizing the quantity and quality of a crop it is necessary to identify the constraints that may affect it and to devise methods of overcoming them through the use of inputs or changes in management practices.     

Predicting crop growth under different cropping and fertilizing management practices

Simulation models are widely used to make predictions of crop growth and yield, and soil carbon and nutrient dynamics under various agricultural practices and soil-climatic conditions. An analytical model of soil carbon and nutrient dynamics, K-model, was expanded to include a plant sub-model (K-Model-P). This allows for the prediction of short- and long-term crop growth, and soil carbon and nitrogen dynamics. The simulations for a short-term experiment (2 growing seasons) with three nitrogen application rates showed that K-Model-P correctly predicted the growth processes of above-ground plant biomass and grain yields. Predicted and measured daily accumulative biomass were significantly correlated, and differences were statistically insignificant. The simulation results for long-term experiments (70 years) of two crop rotations with three soil amendments showed that predicted and measured annual straw and grain yields were significantly correlated, with the differences of less than 13%. Annual crop straw and grain yields can be estimated by the model without significant errors. The agreement between the predicted daily growth and annual yields and experimental data illustrated that the K-Model-P can be used to produce reliable predictions for daily and annual crop growth.     

Modelling crop production potentials for yield gap analysis under semiarid conditions in Guquka, South Africa

Abstract. Hierarchical crop growth models can contribute significantly to land quality research because the yield gap between the estimated optimum and the actual crop production has been identified as a major land quality indicator. This study describes a three-level, hierarchical crop production model, simulating radiation-thermal, water-limited and natural production potentials of annual crops. Input requirements have been kept low to ensure its applicability to developing regions, which often have access only to limited data. The simplicity of this model also has disadvantages: inconsistencies have been reported when applying this model in semiarid regions, which are characterized by very irregular rainfall patterns. Revision of the water balance, which simulates the availability of water, was required. The modified model was validated using the experimental yields of maize and sunflower in Guquka, a semiarid region of South Africa. Yields were estimated very well, possible improvements to crop production were identified and implications for land-use planning highlighted. Yield gap analysis revealed that radiation, sunshine and temperature are favourable for crop production, but the heavy dependence on rainfall makes the region very vulnerable to drought, with devastating impact on yields. The generally low chemical soil fertility further reduces crop performance.     

Sugarcane by-products used as soil amendments on a sandy soil: Effects on sugarcane crop nutrition and yield

Agricultural by-products applied as soil amendments have the potential to improve crop production on low organic matter (OM) soils. This two-year study investigated the use of two readily available sugarcane (Saccharum spp.) milling by-products, mill mud, and mill ash, as soil amendments to improve first sugarcane crop (plant cane) and subsequent crop (first ratoon) grown on a sandy Spodosol. Sugarcane was grown in lysimeters receiving mill mud, mill ash, and a 50:50 (v:v) mill mud to mill ash mix. Amendments were applied at low, medium, and high application rates (5, 10, and 15 cm depths, respectively) and then incorporated 30 cm deep. Amendment effects on plant nutrition, soil characteristics, and crop yield were determined. High rate applied mill mud and mill ash had the highest soil OM content for both years and soil OM did not significantly change between crops for all treatments except for high rate mill mud, which increased the second year (ratoon crop). Leaf nutrient levels for nitrogen (N), iron (Fe), and copper (Cu) for all treatments both years were insufficient; nutrient levels for magnesium (Mg), manganese (Mn), and silicon (Si) were within marginal to sufficient range for all treatments both years. All amendments produced significantly higher biomass and sucrose yields for plant cane and first ratoon crops compared to the control. Mill ash treatments produced the greatest increase in sucrose and biomass yields from plant cane to ratoon crops, which corresponded with an increase in potassium (K) in leaf tissue. However, mid and high rates of mix produced the highest sugarcane biomass and sucrose yields for the both the plant cane and ratoon crops.     

Greenhouse crops: A review

Concerns over increasing production costs and decline in crop revenues have prompted the greenhouse industry to reevaluate criteria used to select crops for greenhouse systems. In the past, crop selection was primarily based on profitability and the strategy was to manipulate the environment to tailor it to the requirements of the crop. As greenhouses are currently evolving from high energy‐consuming to cost‐efficient systems, an emerging strategy is to manipulate the crop to meet the characteristics of the greenhouse environment. To ensure efficient crop manipulation, however, an in‐depth understanding is needed of the inherent ability of crops to adapt and render economic yields under suboptimal conditions. This paper reviews key features of selected greenhouse crops, assesses the impact of changing environment on crop performance, and examines potential avenues for crop manipulation.     

Quantifying effects of simple wheat traits on yield in water-limited environments using a modelling approach

Availability of water for plant growth is a key factor determining plant distribution in natural ecosystems and is the most important limiting factor in agricultural systems. The high environmental and economical cost of irrigation, required to maintain grain yields in water scarce environments, gives an incentive for improvements in water use efficiency of the crop. The objective of our study is to quantify the effects of changes in simple component plant traits on wheat yield under limited water supplies using a modelling approach. The Sirius wheat simulation model was used to perform analyses at two contrasting European sites, Rothamsted, UK and Seville, Spain, which represent major wheat growing areas in these countries. Several physiological traits were analysed to explore their effects on yield, including drought avoidance traits such as those controlling wheat development (phyllochron and grain filling duration), canopy expansion (maximum surface area of culm leaves) and water uptake (root vertical expansion rate and efficiency of water extraction) and drought tolerance traits such as responses of biomass accumulation and leaf senescence to water stress. Changes in parameters that control the effect of water stress on leaf senescence and biomass accumulation had the largest impact on grain yield under drought. The modified cultivar produced up to 70% more yield compared with the control for very dry years. Changes in phenology parameters, phyllochron and grain filling duration, did not improve yields at either site, suggesting that these parameters have been already optimised for climates in the UK and Spain through the breeding process. Our analysis illustrates the power of modelling in exploring and understanding complex traits in wheat. This may facilitate genetic research by focusing on experimental studies of component traits with the highest potential to influence crop performance.