Agronomic and environmental aspects of phosphate fertilizers varying in source and solubility: an update review

This review discusses and summarizes the latest reports regarding the agronomic utilization and potential environmental effects of different types of phosphate (P) fertilizers that vary in solubility. The agronomic effectiveness of P fertilizer can be influenced by the following factors: (1) water and citrate solubility; (2) chemical composition of solid water-soluble P (WSP) fertilizers; (3) fluid and solid forms of WSP fertilizers; and (4) chemical reactions of P fertilizers in soils. Non-conventional P fertilizers are compared with WSP fertilizers in terms of P use efficiency in crop production. Non-conventional P fertilizers include directly applied phosphate rock (PR), partially acidulated PR (PAPR), and compacted mixtures of PR and WSP. The potential impacts of the use of P fertilizers from both conventional (fully acidulated) and non-conventional sources are discussed in terms of (1) contamination of soils and plants with toxic heavy metals, such as cadmium (Cd), and (2) the contribution of P runoff to eutrophication. Best practices of integrated nutrient management should be implemented when applying P fertilizers to different cropping systems. The ideal management system will use appropriate sources, application rates, timing, and placement in consideration of soil properties. The goal of P fertilizer use should be to optimize crop production without causing environmental problems.     

32P isotopic techniques for evaluating the agronomic effectiveness of rock phosphate materials

Tropical soils are often low in available P and therefore require inputs of P fertilizer for optimum plant growth and production of food and fiber. The cost of applying imported or locally produced, water-soluble, P fertilizers is often greater than utilizing indigenous phosphate rock. Therefore quantifying the P availability of soils amended with phosphate rock-based products in a variety of crop management and environmental conditions in developing countries is desirable for making recommendations on best type and rate of fertilizers to use to obtain maximum agronomic and economic benefits. One adequate approach for evaluating the agronomic effectiveness of rock phosphate materials is through the use of³²P/³³P isotopic tracers. The present paper describes the principles and assumptions of the³²P isotopic techniques commonly used in the field and greenhouse for the agronomic evaluation of rock phosphate materials. An overview of the applications of these techniques is also given.     

Direct and residual fertilizer phosphorus effects on yield and phosphorus efficiency of upland rice in an Ultisol

Phosphorus (P) deficiency is one of the major limiting factors for crop production in highly weathered soils in the humid zone of West Africa. Very few studies have evaluated the residual value of fertilizer P to rice in these soils. Field experiments were conducted for three years (1993–1995) to determine the response of four upland rice cultivars to fertilizer P applied at 0, 45, 90, 145 and 180 kg P ha^-1 only once in 1993, and to fertilizer P residues in 1994 and 1995. The soil at the experimental site, in the humid forest zone of Ivory Coast (West Africa), was an Ultisol, low in available P. Grain yields of the rice cultivars were significantly increased by fertilizer P in 1993, and by the fertilizer P residues in 1994 and 1995 although the magnitude of response decreased with time since the fertilizer was applied. The cultivars differed in cumulative agronomic and physiological efficiencies, and the efficiencies were higher at the lower rates of P. The amounts of total P removed in three successive crops were similar for all the four rice cultivars although P harvest index was 10–12% higher in the P efficient than inefficient cultivars. The results suggest that the differences observed in the P efficiency of rice cultivars are due to differences in the internal efficiency of P. This revised version was published online in August 2006 with corrections to the Cover Date.     

Evaluation of two rock phosphates and a calcined rock phosphate as maintenance fertilizers for crop — pasture rotations in Western Australia

Two long-term (11 and 12 y) field experiments in south-western Australia are described that measured the relative effectiveness of three rock phosphate fertilizers (C-grade ore, Calciphos and Queensland (Duchess) rock phosphate), single, double and triple superphosphate. The experiments were on established subterranean clover (Trifolium subterraneum) — based pasture that had received large, yearly, applications of single superphosphate for many years before the experiments began so that in the first year the nil phosphorus (P) treatment produced 80 to 90% of the maximum yield. The experiments were conducted using a rotation of one year cereal crop (oats,Avena sativa at one site, and barley,Hordeum vulgare, at the other): 2 y pasture, a typical rotation on farms in the region. Five levels of each P fertilizer were applied every third year with the crop. Grain yield of cereals, P content of grain, pasture yield, and bicarbonate-soluble P extracted from the soil (available P) were used to estimate fertilizer effectiveness values.The three superphosphate fertilizers had identical values of fertilizer effectiveness. Superphosphate was always the most effective fertilizer for producing grain. The rock phosphate fertilizers were one-seventh to one-half as effective per kg P as superphosphate when assessed on the yield or P content (P concentration × yield) of grain within each cropping year. Bicarbonate-extractable soil P values demonstrated that superphosphate was two to fifteen times as effective as the rock phosphate fertilizers. The relationship between grain yield and P content in grain (i.e. the internal efficiency of P use curve) was similar for the different P fertilizers. Thus for all P fertilizers yield was not limited by other factors as it varied solely in response to the P content, which in turn presumably depended on the P supply from the fertilizers.The relative agronomic effectiveness of rock phosphates is greater for marginally P deficient soils than for highly P deficient soils but rock phosphate remains less effective than superphosphate. We conclude that the rock phosphates studied should not be substituted for superphosphate as maintenance fertilizers for soils in Western Australia that are marginally deficient in P. This result is consistent with the results of many field experiments on highly P deficient soils in south-western Australia. These have shown that a wide variety of rock phosphate fertilizers are much less effective than superphosphate in both the short and long term.     

我国磷矿资源形势与可持续供应的对策建议

磷矿石是生产磷肥的重要原料 ,作为世界上重要的磷矿生产国和消费国 ,我国磷矿储量虽然总量不少但质量不好 ,高品位富矿仅占 8%左右 ,仅能满足国内至 2 0 15年的需求 ,而且集中在交通不便的西南地区。为实现磷矿资源可持续供应 ,促进我国磷肥工业可持续发展 ,必须采取措施加强磷矿资源保护与合理利用。     

Nitrogen Cycling with Respect to Environmental Load in Farm Systems in Southwest China

In Qibainong, a steep-mountainous karst region in southwestern China, self-sustaining societies have long existed, but increasing socioeconomic liberation has fuelled the recent rapid structural change of its economy. Consequently, environmental deterioration and exhaustion of resources have become problematic issues. We carried out a field survey in Qibainong in southwestern China and used both estimated and measured N flows and N balances from obtained results. Our results are summarized as follows (1) farmers used large amounts of chemical N fertilizers at intensities of 113–1124 kg N ha⁻¹; (2) substantial application of chemical fertilizer in Qibainong has contributed to an increase in potential NO₃-N leaching of 6–511 kg N ha⁻¹, followed by NH₃ volatilization; (3) crop products are largely distributed to feed livestock, the products of which are a major income source; (4) this area has a great requirement for imported food; (5) in addition, unused manure N (up to 191 kg N ha⁻¹) is generated by the increase in manure N production. Chemical fertilizer application, in addition to unused manure can be regarded as a major source of environmental damage. Based on the relationship between the N application rate and the NO₃-N leaching potential, we estimated the critical limit of the N application rate of chemical fertilizer + manure to be 297 kg N ha⁻¹. In Qibainong, unused manure, which is an important nutrient resource, was applicable within the critical limit. We recommend that all manure N produced within the village be used effectively on arable land, and that any shortages be supplemented by chemical N fertilizer up to 297 kg N ha⁻¹ to maintain water resource quality. Further improvement might be achieved through incorporating chemical fertilizers, P and K supplemented manure, and so on.     

国内外化肥工业发展的新动向

本文针对我国当前化肥利用率低，污染环境，耗能较高等问题，提出应在节能，无害，高浓度，专特等４个方面生产出口质量高的化肥品种。论述了国外化肥正在向缓效，流体，复合高浓度，专特等方面发展；国内化肥正开展产品改性，发展生物复肥，开发功能性复肥，复混肥专用化等工作，指出了当前我国化肥工业中的存在主要问题，并对如何发展化肥工业提出几点看法。     

对我国缓／控释肥料发展的思考和建议

缓／控释肥料具有提高化肥利用率、减少使用量与施肥次数、降低生产成本、减少环境污染、提高农作物产品品质等优点,代表着新型肥料产业的发展方向。概述了我国缓／控释肥料的现状、发展趋势以及发展过程中存在的问题,同时解读了相关国家政策。     

Using mucuna and P fertilizer to increase maize grain yield and N fertilizer use efficiency in the coastal savanna of Togo

To reduce severe soil degradation associated with agriculture an intensified land-use system is being promoted in West African countries. Most soils of the West African savanna zones are so poor that the efficiency of mineral fertilizers, if applied, is very low. For this reason and because of their high cost and unavailability, many small-scale farmers are reluctant to apply fertilizer. This work investigates a fertilizer management strategy using integrated soil fertility management with a leguminous cover crop (mucuna) so as to improve the soil fertility and increase the use efficiency of fertilizer. The experiment was conducted in the coastal savanna of Togo at Djaka Kopé. The aim was to evaluate the effectiveness of mucuna short fallow (MSF) in increasing maize grain yield through an improved use efficiency of mineral fertilizer. A 2-year maize–mucuna relay intercropping system was compared with continuous sole maize cropping. Fertilizer treatments were factorial combinations of 0, 50 and 100 kg nitrogen (N) ha^–1 and 0, 20 and 40 kg phosphorus (P) ha^–1. While maize grain yield was significantly increased by N fertilization, P did not show any important effect on grain yield. With no N and P applied, grain yield after MSF was on average 40% (572 kg ha^–1) higher than without. The response to N was much greater than the response to MSF, indicating that N was undoubtedly the key element for maize yield building. P fertilization and MSF together positively influenced the apparent N recovery fraction (NRF). N uptake alone did not reflect on its own the yield obtained, and the relationship between grain yield and N uptake is shifted by MSF, with the grain yield increase per unit of N uptake being higher with than without MSF. Combining MSF and P fertilization may therefore lead to improved N use efficiency, making the application of fertilizer N (lower rates) more attractive to small-scale farmers.     

欧盟农业和环境政策对化肥消费和生产的影响

农业施肥引起的环境污染不仅在发达国家,而且在发展中国家也日益受到重视.自1992年欧盟实施以农业-环境一揽子计划为主导思想的新的共同农业政策以来,已有效地控制了农业生产对环境的污染.但该政策也对欧盟化肥消费和生产造成了严重的影响.本文通过欧盟农业和环境政策对保护环境及对肥料生产消费影响的介绍,为国内了解欧盟目前农业和环境状况以及制定农业生产、环境保护政策和化肥生产方向提供借鉴.由于国内化肥用量过高,肥料养分利用率低,环境污染严重,尽管目前还没有类似欧盟农业和环境政策的法规,但相信不久的将来政府也会提出相应的法规,因此,化肥行业必须抓紧研究相关问题,尽快制定应对措施.     

国际磷矿工业发展趋势

本文从磷矿资源、磷矿生产、磷矿石的进出口以及世界磷矿石和磷肥的贸易角度,阐明目前磷矿工业的矿肥结合发展方向,提出中国的对策应是限制并停止磷矿石的出口,就地发展自己的磷肥工业,以减少高价的高浓度磷复肥的进口。     

我国复混肥的生产和发展

我国复混肥工业经20年发展,在基础肥料生产,化肥二次加工,复混肥加工技术研究开发和农化服务等方面取得的成就为我国复混肥发展创造了条件。复混肥厂应积极参与农化服务工作,开展测土配方,科学施肥,提高化肥利用率,减少对环境污染,促进我国复混肥的发展。     

A farm-level evaluation of nitrogen and phosphorus fertilizer use and planting density for pearl millet production in Niger

Mineral fertilizer use is increasing in West Africa though little information is available on yield response in farmers' fields. Farmers in this region plant at low density (average 5,000 pockets ha^–1, 3 plants pocket^–1), which can affect fertilizer use efficiency. A study was conducted with 20 farmers in Niger to assess the response of pearl millet [Pennisetum glaucum (L.) R. Br.] to phosphorus and nitrogen fertilizers under farm conditions. In each field, treatments included control, single superphosphate (SSP) only, SSP plus N (point placed near plant), and either SSP or partially acidulated phosphate rock (PAPR) plus N broadcast. N and P were applied at 30 kg N ha^–1 and 30 kg P₂O₅ ha^–1. Farmers were allowed to plant, weed, etc., as they wished and they planted at densities ranging from 2,000 to 12,000 pockets ha^–1. In the absence of fertilizer, increasing density from 2,000 to 7,000 pockets ha^–1 increased yield by 400%. A strong interaction was found between fertilizer use and density. Farmers planting at densities less than 3,500 pockets ha^–1 had average yields of 317 kg grain ha^–1 while those planting at densities higher than 6,500 pockets ha^–1 showed average yields of 977 grain ha^–1. Though phosphate alone increased yields significantly at all densities, little response to fertilizer N was found at densities below 6,000 pockets ha^–1. Significant residual responses in 1987 and 1988 were found to P applied in high-density plots in 1986. Depending on fertilizer and grain prices, analysis showed that fertilizer use must be be combined with high plant density (10,000 pockets ha^–1) or no economic benefit from fertilizer use will be realized.     

德国施肥法的特点和对我国的启示

德国的施肥法将其肥料的施用依法规范。其主要特点是尽可能地提高肥料养分利用率和最大限度地避免因养分流失而造成的环境污染。中国当前过量施用肥料和低利用率而造成对环境污染日趋严重,应参考德国以立法来规范肥料施用的先进概念和管理办法,根据目前中国农业技术水平尽快推行施肥法规。     

Modelling the quantitative evaluation of soil nutrient supply, nutrient use efficiency, and fertilizer requirements of wheat in India

Wheat yields in many parts of India are stagnant. The main reason forthis is conventional blanket fertilizer recommendation, lower fertilizer useefficiency, and imbalanced use of fertilizers. Estimation of fertilizerrequirements based on quantitative approaches can assist in improving wheatyields and increasing nutrient use efficiency. We used the QUEFTS (QUantitativeEvaluation of Fertility of Tropical Soils) model for estimation of nitrogen(N),phosphorus (P), and potassium (K) requirements and fertilizer recommendationsfor a target yield of wheat. The model considers the interactions of N, P, andK, and climate adjusted potential yield of the region. Published data fromseveral field experiments dealing with N, P, and K conducted during the years1970 to 1998 across wheat-growing environments of India, covering a wide rangeof soil and climatic conditions, were used to reflect the environmentalvariability. The relationships between indigenous N, P, and K supply and soilorganic carbon, Olsen P, and ammonium acetate-extractable K, respectively, wereestablished. The required N, P, and K accumulation in the plant for 1 tonnegrain yield was 23.1, 3.5, and 28.5 kg, respectively, suggestinganaverage NPK ratio in the plant dry matter of about 6.6:1:8.1. The constants forminimum and maximum accumulation (kg grain kg^–1) of N (27 and60), P (162 and 390), and K (20 and 59) were derived as the standard modelparameters in QUEFTS for fertilizer recommendation for irrigated wheat in thetropical and subtropical regions of India. Relationships of apparent recoveryefficiencies of fertilizer N, P, and K with levels of their application werealso determined. The observed yields of wheat with different amounts of thesenutrients were in good agreement with the values predicted by the model,indicating that the model can be used for fertilizer recommendations.     

Crop residue,manure and fertilizer in dryland maize under reduced tillage in northern China: I grain yields and nutrient use efficiencies

The rapidly increasing population and associated quest for food and feed in China has led to increased soil cultivation and nitrogen (N) fertilizer use, and as a consequence to increased wind erosion and unbalanced crop nutrition. In the study presented here, we explored the long-term effects of various combinations of maize stover, cattle manure and nitrogen (N) and phosphorus (P) fertilizer applications on maize (Zea mays L.) yield and nutrient and water use efficiencies under reduced tillage practices. In a companion paper, we present the effects on nutrient balances and soil fertility characteristics. The ongoing factorial field trial was conducted at Shouyang Dryland Farming Experimental Station in northern China from 1993 onwards. The incomplete, determinant-optimal design comprised 12 treatments, including a control treatment, in duplicate. Grain yields and N, P, and potassium (K) uptakes and N, P and K use efficiencies were greatly influenced by the amount of rain during the growing season (GSR), and by soil water at sowing (SWS). There were highly significant interactions between GSR and added stover and manure, expressed in complex annual variations in grain yield and N, P and K use efficiencies. Annual mean grain yields ranged from 3,000 kg ha⁻¹ to 10,000 kg ha⁻¹ and treatment mean yields from 4,500 kg ha⁻¹ to 7,000 kg ha⁻¹. Balanced combination of stover (3,000–6,000 kg), manure (1,500–6,000 kg) and N fertilizer (105 kg) gave the highest yield. Stover and manure were important for supplying K, but the effects differed greatly between years. Overall mean N recovery efficiency (NRE) ranged from 28% to 54%, depending on N source. NRE in wet years ranged from 50% to 90%. In conclusion, balanced combinations of stover, manure and NP fertilizer gave the highest yield and NRE. Reduced tillage with adding stover and manure in autumn prior to ploughing is effective in minimizing labor requirement and wind erosion. The potentials of split applications of N fertilizer, targeted to the need of the growing crop (response farming), should be explored to further increase the N use efficiency.     

Fertilizer requirements for wheat and maize in China: the QUEFTS approach

Wheat and maize are two major food crops in China. Conventional fertilizer recommendations result in higher than necessary costs to farmers and increased environmental pollution. It is essential to quantitatively estimate optimal fertilizer requirements to alleviate the problems of the two crops in China. The QUEFTS (QUantitative Evaluation of the Fertility of Tropical Soils) model was used to estimate region-specific nitrogen (N), phosphorus (P) and potassium (K) requirements as well as fertilizer applications needed to realize target yields of wheat and maize. Data of field experiments with different fertilization treatments of various regions in China during the years of 1985–1995 were used to calibrate the QUEFTS model for both wheat and maize. Minimum and maximum internal nutrient efficiencies (kg grain kg⁻¹) for the model were estimated at N (25 and 56), P (171 and 367), K (24 and 67) for wheat, and N (21 and 64), P (126 and 384), K (20 and 90) for maize. The model suggested a linear increase of grain yields for scenarios with nutrient contents of 24.6, 3.7 and 23.0 kg N, P and K per 1000 kg of wheat grain and 25.8, 4.3 and 23.1 kg N, P and K per 1000 kg of maize grain. These results suggest that the average N: P: K ratio in the plant dry matter is about 6.7: 1: 6.2 for wheat and 6.0: 1: 5.4 for maize. Relationships between internal N, P and K levels and soil properties were established and relationships between the recovery efficiencies of applied fertilizer – N, P and K were found. Running the calibrated QUEFTS model with observed field data produced a good fit between predicted and observed data. It was concluded that the calibrated QUEFTS model could be a useful tool for improving fertilizer recommendations for wheat and maize in China.     

2016年我国磷复肥行业生产情况及2017年发展趋势

阐述2016年我国磷复肥行业运行情况:磷肥产量同比下降7.4％;产能向资源地集中的趋势更加明显,云、贵、川、鄂4省产量占总产量的78.3％;行业集中度继续提升,大型优势企业规模不断扩大;净出口量降低18.5％;优惠政策取消,市场价格低迷,企业成本增加,环保投入提升,磷复肥行业主营业务利润率同比下降1.1个百分点.分析2017年磷复肥行业发展趋势.     

Effectiveness of different phosphatic fertilizers measured using labelled superphosphate and phosphorus taken up by plants

The agronomic effectiveness of three P fertilizers (diamonium phosphate, rock phosphate and compost) was studied in a greenhouse experiment using wheat. A radioisotopic method, using triple superphosphate labelled with³²P, was used to evaluate the P in dried tops that was derived from i) the soil, ii) labelled superphosphate and iii) the fertilizer being studied.The ratio between P uptake from each fertilizer and P uptake from the soil was used to compare the effectiveness of the different fertilizers. P derived from diammonium phosphate was greater than P derived from the soil, except in one soil. P derived from rock phosphate was always lower than P derived from the soil. The effectiveness of compost depended on soil type. Compost can produce two kind of effects: i) a direct P contribution and ii) an indirect effect improving P uptake from the soil. The radioisotopic method can be used to study the effectiveness of fertilizers even when there are no differences in yield.     

再议“我国复混肥行业现状及发展机遇”

2006年我国化肥实物产量约为1.6亿t,全国化肥平均养分约为33%,单纯追求化肥养分含量高,不利于资源合理利用.我国复合肥产能已超3亿t,实物产量约为5 000万t,产能利用率低.着重讨论了功能性肥料的开发.生产中、低浓度肥料的必要性,比较了我国复合肥行业与国外的差距.