Long-term fertilizer trials on loam soil at M⊘ystad,south-eastern Norway: Crop yields,nutrient balances and soil chemical analyses from 1983 to 2003

Abstract

Factorial combinations of N, P and K fertilizer have been compared with the use of farmyard manure at M?ystad since 1922 in a seven-year crop rotation (3 ley, oat, potato, wheat, barley). Until 1982, low inputs of N fertilizer (22 kg ha^?1) were used. In 1983, they were brought into line with current farming practice. This paper presents the results of three subsequent rotations. Yields without any fertilizer were on average 48% of those with 100 kg N ha^?1 in compound fertilizer, whilst those with 20, 40 and 60 Mg ha^?1 farmyard manure were 81, 87 and 90%, respectively. Yields with other combinations of N, P and K declined in the order NP, NK, N, PK and K. When NPK fertilizer was used, apparent recoveries of applied fertilizer were close to 50% for N and K, and around 40% for P. Much lower values were found for nutrients applied singly. Balance between N supply and removal was indicated at rates of about 60 kg N fertilizer ha^?1 in potatoes, 75 kg ha^?1 in cereals and 90 kg ha^?1 in leys. A surplus of P was found in all crops at all N levels, and of K in cereals and potatoes. In leys, K balance was achieved with an N supply of 90 kg N ha^?1. Nutrient balance was indicated at a little below 20 Mg ha^?1 yr^?1 farmyard manure. Larger manure applications gave large nutrient surpluses, particularly of N. Soil reaction remained close to neutral with the use of calcium nitrate and manure, but declined with the use of ammonium nitrate. Manure use gave the highest amounts of available P, K and Mg in soil. Similar increases in total inorganic P were found with manure use as with fertilizer use, but amounts of organic P and total K were little affected.     

Effects of Farmyard Manure and Inorganic Fertilizers on Sorghum Growth,Yield, and Nitrogen Use in a Semi-Arid Area of Ethiopia

A field experiment was conducted to assess the effect of the combined use of farmyard manure and inorganic fertilizer on the growth and yield of sorghum and on soil chemical properties in a semi-arid area in northeastern Ethiopia. Twelve treatments comprising factorial combinations of four levels of farmyard manure (0, 5, 10, and 15 t ha^?1) and three levels of inorganic fertilizers (0%, 50%, and 100% of the recommended rate) were compared in a randomized complete block design with three replications over a period of six years. The results revealed significant improvements in the growth and yield of sorghum due to the main and interaction effects of farmyard manure and inorganic fertilizer application. The combined application of farmyard manure and inorganic fertilizers increased post-anthesis dry-matter production by 147%–390% and grain yield by 14%–36%. The main effects of farmyard manure and inorganic fertilizers increased stover yield by 8%–21% and 14%–21%, respectively. Farmyard manure application increased total nitrogen (N) uptake by 21%–36%, grain protein yield by 8%–11%, and grain protein concentration by 20%–29%. Application of farmyard manure along with 50% of the recommended inorganic fertilizer rate resulted in a grain yield equivalent to, or greater than that for 100% of the recommended inorganic fertilizer rate, thus effecting a 50% savings of inorganic N and phosphorus (P) fertilizer. Application of 5, 10, and 15 t farmyard manure ha^?1along with 100% of the recommended fertilizer rate and 5, 10, and 15 t farmyard manure ha^?1 along with 50% of the recommended fertilizer rate can be recommended for farmers who can and cannot afford to buy inorganic fertilizers, respectively.     

Long‐Term Integrated Nutrient Management for Rice‐Based Cropping Pattern: Effect on Growth,Yield, Nutrient Uptake,Nutrient Balance Sheet,and Soil Fertility

Abstract

A 7‐year‐long field trial was conducted on integrated nutrient management for a dry season rice (Boro)–green manure (GM)–wet season rice (T. Aman) cropping system at the Bangladesh Rice Research Institute Farm, Gazipur during 1993–1999. Five packages of inorganic fertilizers, cow dung (CD), and GM dhaincha (Sesbania aculeata) were evaluated for immediate and residual effect on crop productivity, nutrient uptake, soil‐nutrient balance sheet, and soil‐fertility status. Plant height, active tiller production, and grain and straw yields were significantly increased as a result of the application of inorganic fertilizer and organic manure. Usually, the soil‐test‐based (STB) fertilizer doses for a high‐yield goal produced the highest grain yield of 6.39 t ha^?1 (average of 7 years) in Boro rice. Application of CD at the rate of 5 t ha^?1 (oven‐dry basis) once a year at the time of Boro transplanting supplemented 50% of the fertilizer nutrients other than nitrogen (N) in the subsequent crop of the cropping pattern. A positive effect of GM on the yield of T. Aman rice was observed. Following GM, the application of reduced doses of phosphorus (P), potassium (K), sulfur (S), and zinc (Zn) to the second crop (T. Aman) did not reduce yield, indicating the beneficial residual effect of fertilizer applied to the first crop (Boro rice) of the cropping pattern. The comparable yield of T. Aman was also observed with reduced fertilizer dose in CD‐treated plots. The total P, K, and S uptake (kg/ha/yr) in the unfertilized plot under an irrigated rice system gradually decreased over the years. The partial nutrient balance in the unfertilized plot (T₁) was negative for all the nutrients. In the fertilized plots, there was an apparent positive balance of P, S, and Zn but a negative balance of N and K. This study showed that the addition of organic manure (CD, dhaincha) gave more positive balances. In the T_4c treatment at 0–15 cm, the application of chemical fertilizers along with the organic manures increased soil organic carbon by (C) 0.71%. The highest concentration of total N was observed with T_4c followed by T_4d and T_4b, where CD was applied in Boro season and dhaincha GM was incorporated in T. Aman season. The sixfold increase in soil‐available P in T_4b‐, T_4c‐, T_4a‐treated plots was due to the addition of CD. Dhaincha GM with the combination of chemical fertilizer helps to mobilize soil‐available P by 3 to 6 ppm. The highest amount of soil‐available S was found in T_4c‐ and T_4a‐treated plots. It was 2.5 times higher than that of the initial soil. The application of CD and dhaincha GM along with chemical fertilizers not only increased organic C, total N, available P, and available S but also increased exchangeable K, available Zn, available iron (Fe), and available manganese (Mn) in soil.     

Long‐term effects of manure and fertilization on soil organic matter and quality parameters of a calcareous soil in NW China

Long‐term applications of inorganic fertilizers and farmyard manure influence organic matter as well as other soil‐quality parameters, but the magnitude of change depends on soil‐climatic conditions. Effects of 22 annual applications (1982–2003) of N, P, and K inorganic fertilizers and farmyard manure (M) on total organic carbon (TOC) and nitrogen (TON), light‐fraction organic C (LFOC) and N (LFON), microbial‐biomass C (MB‐C) and N (MB‐N), total and extractable P, total and exchangeable K, and pH in 0–20 cm soil, nitrate‐N (NO ‐N) in 0–210 cm soil, and N, P, and K balance sheets were determined using a field experiment established in 1982 on a calcareous desert soil (Orthic Anthrosol) at Zhangye, Gansu, China. A rotation of irrigated wheat (Triticum aestivum L.)‐wheat‐corn (Zea mays L.) was used to compare the control, N, NP, NPK, M, MN, MNP, and MNPK treatments. Annual additions of inorganic fertilizers for 22 y increased mass of LFON, MB‐N, total P, extractable P, and exchangeable K in topsoil. This effect was generally enhanced with manure application. Application of manure also increased mass of TOC and MB‐C in soil, and tended to increase LFOC, TON, and MB‐N. There was no noticeable effect of fertilizer and manure application on soil pH. There was a close relationship between some soil‐quality parameters and the amount of C or N in straw that was returned to the soil. The N fertilizer alone resulted in accumulation of large amounts of NO ‐N at the 0–210 cm soil depth, accounting for 6% of the total applied N, but had the lowest recovery of applied N in the crop (34%). Manure alone resulted in higher NO ‐N in the soil profile compared with the control, and the MN treatment had the highest amount of NO ‐N in the soil profile. Application of N in combination with P and/or K fertilizers in both manured and unmanured treatments usually reduced NO ‐N accumulation in the soil profile compared with N alone and increased the N recovery in the crop as much as 66%. The N that was unaccounted for, as a percentage of applied N, was highest in the N‐alone treatment (60%) and lowest in the NPK treatment (30%). In the manure + chemical fertilizer treatments, the unaccounted N ranged from 35% to 43%. Long‐term P fertilization resulted in accumulation of extractable P in the surface soil. Compared to the control, the amount of P in soil‐plant system was surplus in plots that received P as fertilizer and/or manure, and the unaccounted P as percentage of applied P ranged from 64% to 80%. In the no‐manure plots, the unaccounted P decreased from 72% in NP to 64% in NPK treatment from increased P uptake due to balanced fertilization. Compared to the control, the amount of K in soil‐plant system was deficit in NPK treatment, i.e., the recovery of K in soil + plant was more than the amount of applied K. In manure treatments, the recovery of applied K in crop increased from 26% in M to 61% in MNPK treatment, but the unaccounted K decreased from 72% in M to 37% in MNPK treatment. The findings indicated that integrated application of N, P, and K fertilizers and manure is an important strategy to maintain or increase soil organic C and N, improve soil fertility, maintain nutrients balance, and minimize damage to the environment, while also improving crop yield.     

Enhancing Corn Production Through the Use of Starter Fertilizer in the Northern Great Plains

Abstract

The northern portion of the Great Plains has environmental conditions that require unique management practices to ensure optimum corn (Zea mays L.) yield and quality. The objective was to investigate the effect of starter fertilizer on corn yield and quality under different soil management. A field experiment was established within a 2‐year corn/soybean [Glycine max (L.) Merrill] rotation. Whole‐plot treatments were tillage with split‐plot treatments of starter fertilizer. Starter fertilizer treatments consisted of two nitrogen (N) sources, each at four rates, all contained phosphorus (P) and potassium (K). An additional treatment of no starter fertilizer was also incorporated into the experiment. There was a significant increase in yield with application of starter‐N for all years except 2002. The most dramatic yield increase was obtained with the comparison between the no starter (no N, P, or K) treatment and the P and K treatment (no N+P and K). Starter fertilizer with only P and K also increased yield, oil production, and N removal in all years compared with no starter fertilizer treatment. Application of starter fertilizer can have a significant positive impact on yield and quality of corn grown in the northern Great Plains.     

Einfluß unterschiedlicher Düngung auf pH,N, C und die Gehalte an CAL-extrahierbarem K und P im Boden

Influence of different fertilization on pH, N, C and CAL-extractable K and P in the soil The influence of different fertilization (mineral fertilizer, different kinds and quantities of farmyard manure and biocompost, horn meal) on soil properties was studied during 8 years of cultivation. The plots were planted and harvested as practised under local farming conditions. The pH of the non-fertilized plots decreased from 5.84 to 5.69, while it was increased by fertilization with farmyard manure or biocompost. N_t in the soil was not influenced by different fertilization. C_t was increased by high biocompost application, stayed constant on the other fertilized plots but decreased on the nonfertilized plots from 1.08 to 0.99%. Without fertilization, plant available nutrients were diminished from 7.3 to 4.3 mg P(CAL) 100 g^?1 and from 22.5 to 13.9 mg K(CAL) 100 g^?1. However, if the plots were fertilized with mineral or organic fertilizer, the nutrient content remained on the initial level. Storing farmyard manure under roof or covering with straw or polyethylene sheet did not affect the criteria of soil studied.     

Long‐term fertilization impacts on corn yields and soil organic matter on a clay‐loam soil in Northeast China

A long‐term fertilization experiment with monoculture corn (Zea mays L.) was established in 1980 on a clay‐loam soil (Black Soil in Chinese Soil Classification and Typic Halpudoll in USDA Soil Taxonomy) at Gongzhuling, Jilin Province, China. The experiment aimed to study the sustainability of grain‐corn production on this soil type with eight different nitrogen (N)‐, phosphorus (P)‐, and potassium (K)–mineral fertilizer combinations and three levels (0, 30, and 60 Mg ha^–1 y^–1) of farmyard manure (FYM). On average, FYM additions produced higher grain yields (7.78 and 8.03 Mg ha^–1) compared to the FYM0 (no farmyard application) treatments (5.67 Mg ha^–1). The application of N fertilizer (solely or in various combinations with P and K) in the FYM0 treatment resulted in substantial grain‐yield increases compared to the FYM0 control treatment (3.56 Mg ha^–1). However, the use of NP or NK did not yield in any significant additional effect on the corn yield compared to the use of N alone. The treatments involving P, K, and PK fertilizers resulted in an average 24% increase in yield over the FYM0 control. Over all FYM treatments, the effect of fertilization on corn yield was NPK > NP = NK = N > PK = P > K = control. Farmyard‐manure additions for 25 y increased soil organic‐matter (SOM) content by 3.8 g kg^–1 (13.6%) in the FYM1 treatments and by 7.8 g kg^–1 (27.8%) in the FYM2 treatments, compared to a 3.2 g kg^–1 decrease (11.4%) in the FYM0 treatments. Overall, the results suggest that mineral fertilizers can maintain high yields, but a combination of mineral fertilizers plus farmyard manure are needed to enhance soil organic‐matter levels in this soil type.     

Effect of organic and inorganic sources of nutrients on yield,economics, and energetics of pepper and soil properties in naturally ventilated polyhouse

A field experiment was conducted during the summer season of 2009 and 2010 at Vivekananda Parvatiya Krishi Anusandhan Sansthan, Hawalbagh, Almora, Uttarakhand, under the mid-hills of north-western Himalaya, to study the effect of farmyard manure and fertilizers on fruit yield, economics, energetics of pepper (Capsicum annuum L.) and on soil chemical properties. The highest level of farmyard manure (20 t ha^?1) along with 125% of recommended NPK (125, 27.5, and 52.1 kg N, P and K ha^?1) resulted in significantly higher fruit yield (33.9 t ha^?1) over other combinations. Both farmyard manure and inorganic fertilizers significantly increased fruits/plant, average fruit weight, plant height, fruit length, and fruit diameter. The maximum net returns (4520 $ ha^?1) was achieved at 20 t of FYM along with 125% of recommended NPK. Energy ratio of 1.29 and 1.13 was the highest under 20 t FYM ha^?1 and 125% of recommended NPK, respectively. Available nutrients (N, P, and K) improved the status of the soil significantly due to 20 t ha^?1 of FYM and 125% of recommended NPK over other treatments.     

不同施肥量对绿肥产量和养分积累的影响

大田试验条件下研究不同氮、磷、钾肥用量对绿肥[豆科绿肥紫云英(Astragalus sinicus L.)和禾本科绿肥看麦娘(Alopecurus aequalis Sobol.)]产量及养分积累量的影响。试验结果表明,施肥能显著增加绿肥产量,绿肥鲜草产量较不施肥处理增加42.8%~311.1%,与缺素处理相比,氮、磷、钾肥的增产率分别为57.1%~177.5%、27.8%~178.7%、14.2%~32.4%。两种绿肥的鲜草产量均随氮、磷、钾肥施用量的增加而增加,中、高水平的氮、磷肥用量下看麦娘的产量均高于紫云英,所有钾肥处理的看麦娘产量均高于紫云英。绿肥的养分积累量均随施肥量的增加而增加,中高水平的氮、磷肥用量下看麦娘的氮、磷积累量高于紫云英,不同钾水平下的看麦娘钾积累量均高于紫云英。氮、磷、钾肥用量分别为112.5 kg(N).hm?2、19.7 kg(P).hm?2、37.5 kg(K).hm?2时,两种绿肥总产量及碳、氮、磷、钾积累量最高,分别为49 424 kg.hm?2和3 212 kg(C).hm?2、151 kg(N).hm?2、19.8 kg(P).hm?2、156 kg(K).hm?2。此时看麦娘产量、碳、氮、磷、钾积累量分别占总量的59.0%、65.7%、66.3%和64.4%。紫云英田间自然洒种的看麦娘无成本投入且养分积累量高,不失为一种优质绿肥。     

Nutrient content of maize and soil organic matter status under various tillage methods and farmyard manure levels

Abstract

A two-year field study was conducted under semi-arid conditions in Pakistan to assess the role of tillage systems and farmyard manure on soil, plant nutrients and organic matter content. Four tillage systems (zero, minimum, conventional and deep tillage) and three farm manure levels were used. Maize crop was grown up to maturity. Uptake of N, P and K in maize shoots improved in tillage systems compared to non-tillage and treatments where farmyard manure was applied. Soil N status decreased in the deep tillage systems, whereas it increased in all other tillage systems and in the farmyard manure amended treatments. Increase in soil P values was observed under minimum and conventional tillage, whereas deep tillage resulted in a decrease. Farmyard manure amendments increased soil P and soil K in all systems. Tillage did not affect soil K levels. Results demonstrate that reduced tillage is practicable in arid and semi-arid regions since it improves soil fertility.     

Integrated use of organic and inorganic inputs in wheat-fodder maize cropping sequence to improve crop yields and soil properties

A 2-year field study was conducted to evaluate the effect of two organics, farmyard manure and vermicompost, each at three rates (0, 5, 10 t ha^?1 and 0, 1, 2 t ha^?1, respectively), along with two levels of mineral fertilizer (75% and 100% of recommended dose), on crops yields and soil properties under a wheat–fodder maize cropping sequence. Individual addition of organics at a higher level increased yields of wheat and subsequent maize. Soil microbial biomass carbon was enhanced as both a direct and residual effect with the addition of farmyard manure followed by vermicompost and fertilizer treatments, and also by combined addition of manure with either vermicompost or mineral fertilizer. Farmyard manure increased the availability of soil macro- and micronutrients, whereas vermicompost influenced only the availability of micronutrients at wheat harvest. A residual effect of farmyard manure and mineral fertilizers was found for available N. Meanwhile, the residual status of micronutrients in the soil was either maintained or significantly improved due to organic amendments (Mn and Zn with farmyard manure; Fe and Zn with vermicompost). Interaction of farmyard manure and vermicompost at a higher level benefited the next crop by increasing the yield of fodder maize and improving the availability of P and metals in soil.     

Effects of different potassium fertilizers suitable for use in organic farming systems on grass/clover yields and nutrient offtakes and interactions with nitrogen supply

Abstract. In organic farming systems, fertilizing materials can be used when potassium (K) deficiency is shown, but such systems are dominantly nitrogen (N) limited and this is likely to affect crop utilization of K. The supply of K to grass/clover from a range of mineral and organically based K fertilizers and its interaction with N supply were studied in a greenhouse experiment. Sequential plant cuts were taken for yield and nutrient content determinations in crop and soil. Crop yields were limited by N: where N supply was increased either through the mineralization of N from organic materials (rapemeal, farmyard manure) or inorganic fertilizer, plant yields increased significantly. Grass/clover responded better to additional K where sufficient N was available. However, yield responses to K were generally small, even in the presence of adequate N. Of the different fertilizers, kali and MSL-K increased yields above those of the control by less than 5%, sylvinite, DKSI and farmyard manure by 10–20%, and rapemeal and potassium sulphate by more than 25%. In all treatments, K offtakes in the grass/clover were considerably greater than fertilizer K inputs. The grass/clover showed an increased uptake of Na where insufficient K was available. However, the Mg content of the grass/clover was not adversely affected by K fertilizer application. Organic farmers need to consider the soil K status, the rotational nutrient budget, the supply of all nutrients in fertilizing materials and nutrient interactions to achieve effective K management in organic farming systems.     

Alkaline coal fly ash amendments are recommended for improving rice-peanut crops

Abstract

A field experiment investigating amendments of organic material including farmyard manure, paper factory sludge and crop residues combined with fly ash, lime and chemical fertilizer in a rice-peanut cropping system was conducted during 1997–98 and 1998–99 at the Indian Institute of Technology, Kharagpur, India. The soil was an acid lateritic (Halustaf) sandy loam. For rice, an N:P:K level of 90:26.2:33.3 kg ha^?1 was supplied through the organic materials and chemical fertilizer to all the treatments except control and fly ash alone. The required quantities of organic materials were added to supply 30 kg N ha^?1 and the balance amount of N, P and K was supplied through chemical fertilizer. Amendment materials as per fertilization treatments were incorporated to individual plots 15 days before planting of rice during the rainy season. The residual effects were studied on the following peanut crop with application of N:P:K at 30:26.2:33.3 kg ha^?1 through chemical fertilizer alone in all treatments, apart from the control. An application of fly ash at 10 t ha^?1 in combination with chemical fertilizer and organic materials increased the grain yield of rice by 11% compared to chemical fertilizer alone. The residual effect of both lime and fly ash applications combined with direct application of chemical fertilizer increased peanut yields by 30% and 24%, respectively, compared to chemical fertilizer alone. Treatments with fly ash or lime increased P and K uptake in both the crops and oil content in peanut kernel compared to those without the amendments. Alkaline coal fly ash proved to be a better amendment than lime for improving productivity of an acid lateritic soil and enriching the soil with P and K.     

长期施用化肥和农家肥对土壤化学性质和作物产量的影响

A long-term fertiliztion experiment was carried out in an experimental field in Lyczyn near Warsaw,Poland.Application ofmineral fertilizers ,especially Nfertilizer with and without farmyard manure accel-erated the eacidification process of the soil.Application of 1.6 t CaO ha^-1 every four years was essential to maintenance of the soil pHKCl at 5.5-6.6 and base saturation degree above 60% Application of 50 t farmyard manur ha^-1 every 4 years,whih contained 46 kg P and 240 kg K,was sufficient to maintain boh the K and P fertility of the soil.Besides,it was beneficial to alleviating soil acidifcation. As a result of long-term unbalanced fertilization,yield responses to N,P and K fertilizers incereased significantly with time.the efficiency of N from farmyard manure was found to be comparable to that of N fertilizer during 1988-1991.     

氮肥运筹、配施有机肥和坐水种对春玉米产量与养分吸收转运的影响

采用田间试验方法,研究了氮肥运筹、配施有机肥和坐水种对春玉米产量与养分吸收转运的影响。结果表明,适宜氮肥运筹方式、配施有机肥和坐水种均能显著增加春玉米产量,氮肥两次追肥处理的产量较一次追肥处理的产量增加10.6%～17.0%,配施有机肥增产10.3%～18.0%,坐水种增产9.1%,配施有机肥并坐水种增产20.4%。氮肥两次追施、配施有机肥及配施有机肥并坐水种均能显著提高春玉米干物质最大积累速率和积累总量,分别提高干物质最大积累速率11.1%～29.5%、28.0%～28.8%和32.1%,依次提高干物质积累总量11.9%～15.5%、21.2%～24.4%和26.9%。氮肥两次追施、配施有机肥和坐水种均可提高N、P、K养分最大吸收速率和吸收总量,养分最大吸收速率以K最高,N居中,P最低;养分吸收总量以N最高,K居中,P最低;养分最大吸收速率出现的时间以K最早（57.2～60.4 d）,N居中（65.3～68.5 d）,P最晚（71.4～74.8 d）,三者均早于干物质积累最大速率出现的时间（82.5～89.3 d）。氮肥两次追施、配施有机肥和坐水种均有利于N、P、K养分由营养体向籽粒的转运量、转运效率、籽粒中养分含量以及氮肥利用率的提高,养分转运效率以P最高（59.3%～66.1%）,其次是N（41.5%～55.1%）,K最低（35.9%～38.0%）。在本实验条件下,施氮量为225 kg/hm2,基肥:拔节肥比1:3,配施有机肥结合坐水种,为最佳施肥处理。     

绿肥配施氮肥对双季稻产量和养分吸收的影响

基于2016年的田间定位试验，在冬闲(F)和冬种绿肥(G)2种模式下，探究不同施氮量(N0:不施氮；N50:减氮50%;N100:常规氮；N150:增施氮50%)对双季稻产量、养分吸收特征及氮素利用率的影响，以期为南方稻区绿肥利用和氮肥施用提供科学理论依据。结果表明，与冬闲模式相比，冬种绿肥模式提高4种不同氮水平下的早晚稻产量，其中早、晚稻稻谷产量平均增产8.0%,5.7%。2种模式下的早稻产量随施氮量增加均呈现出先增加后降低的趋势，而晚稻则呈现上升的趋势。冬种绿肥模式同样提高植株地上部氮(N)、磷(P)和钾(K)素积累量和氮肥偏生产力。随施氮量的增加，这2种模式的早晚稻养分收获指数和氮肥利用率大多呈下降趋势，高量氮肥处理(N150)降低早稻地上部K素的积累量。早晚稻稻谷产量与水稻N、P和K素积累量存在显著正相关，2种模式下的高氮处理(N150)K素吸收的降低与其早稻产量下降相关联。结合稻谷产量与施氮量拟合分析、养分吸收利用等多方面效应，综合考量，冬闲模式下，早稻季氮肥适宜施用范围为150.0～170.3 kg/hm²,冬种绿肥模式下，早稻季氮肥适宜施用范围为75...     

不同耕作与施肥方式下白土水稻产量及养分吸收量

通过定位试验,研究白土上不同耕作措施及有机肥施用对水稻产量、 养分吸收量及土壤理化性状的影响。试验设置2个翻耕深度（10 cm和20 cm）与4种施肥模式（单施化肥、 化肥+畜禽粪、 化肥+秸秆、 化肥+绿肥）。结果表明,单施化肥时,翻耕20 cm处理两年的平均产量较翻耕10 cm处理减产7.6%; 而在翻耕20 cm的基础上,秸秆还田或施用畜禽粪、 绿肥则可以显著提高水稻产量,较单施化肥分别增产14.8%、 16.1% 和14.6%。水稻养分吸收量也表现出相同规律,在翻耕20 cm后补充有机肥能显著增加植株对氮、 磷、 钾的吸收。同时,翻耕 20 cm结合秸秆还田或施用畜禽粪、 绿肥处理的土壤有机质、 全氮、 碱解氮、 速效磷和速效钾含量均高于单施化肥处理。在白土稻田上,翻耕20 cm后增施有机肥有利于提高水稻产量,促进养分吸收,改善白土耕层土壤理化性状,是适合白土区大力推广的施肥模式。     

长期施氮、磷、钾化肥对玉米产量及土壤肥力的影响

以1990年建立的国家褐潮土土壤肥力与肥料效益长期监测基地(北京昌平站)的长期肥料定位试验为研究平台,研究了不同施肥制度对玉米产量和土壤肥力的影响。结果表明,长期均衡地施NPK肥或NPK与有机肥配施,可以显著提高玉米产量和土壤有机质、全氮、全磷、速效氮、速效磷、速效钾等肥力指标,并能提高土壤微量元素的含量;而不均衡施肥(N、NK、NP、PK)导致相应的营养元素的耗竭。相关分析表明,在褐潮土上增施磷肥和有机肥对提高玉米产量具有重要的作用。     

黄土高原旱地长期施肥对小麦养分吸收和土壤肥力的影响

通过定位试验研究了长期施肥对小麦子粒、秸杆养分吸收和土壤肥力变化的影响。结果表明,合理施用化肥不但增产幅度大,还在一定程度上增加了小麦N、P、K养分浓度。单施氮、单施磷肥能增加小麦子粒和秸杆的N、P、K吸收量,氮磷肥配施增加效果显著,其子粒吸收N、P、K增加了153.2%、157.1%和162.4%。施有机肥能补充土壤中的N、P、K含量,增加小麦子粒中的养分含量,使品质有大幅度的提高。单施磷肥的土壤有机质、全P、速效P含量增加,土壤全N、速效N含量减少,N素亏缺。氮磷肥配施加剧了土壤K的亏缺。有机肥培肥作用显著,有机肥和氮、磷肥配施的土壤有机质、全N、全P、速效N、速效P和速效K分别增加了69.0%5、7.5%、54.8%、73.1%、830.5%和119.1%。     

EFFECT OF FERTILIZATION ON YAM (DIOSCOREA ROTUNDATA) BIOMASS PRODUCTION

The influence of different fertilization practices [i.e., nitrogen (N), phosphorus (P), and potassium (K) fertilizers, crop residue, and manure] on dry matter production of white yam (Dioscorea rotundata) “kokoro” a late variety of yam, tuber biomass and dry matter distribution to the plant parts was determined in upper Oueme basin (Republic of Benin) in the years 2001, 2002 and 2003. The experimental design was a randomized complete block with four replications. Altogether there were eight plots divided into two groups consisting of four plots each, one was treated with manure (at the rate of 10 ton ha^?1), second plot with mineral fertilizer (N30:P30:K60), third plot with combination of manure and mineral fertilizer, whereas the fourth plot was left as control (no application of fertilizer). In year 2002 and 2003 the same combinations were made taking crop residues (at the rate of10 ton ha^?1) from external sources as a source of organic matter at the place of manure. Manure application did not have a significant effect on yam total biomass production nor on tuber yield when applied on fields after fallow. Whereas crop residue application had a positive significant effect on yam tuber and total biomass production when applied after cotton and maize and with adequate rainfall amount and distribution. Regarding partitioning pattern in yam crop, no effect of different practices of fertilization has been noticed. The crop behaves identically (i.e, partitioning rate) in both fertilized and unfertilized management practice.