长期施肥稻田土壤基础地力和养分利用效率变化特征

【目的】 研究长期不同施肥措施对土壤基础地力和氮磷钾养分吸收利用效率的影响,探明土壤基础地力和氮、磷、钾养分吸收利用效率的相互关系。 【方法】 采集双季水稻种植制度下 33 年长期定位施肥试验的不施肥 (CK)、施氮磷钾肥 (NPK) 和氮磷钾肥配施稻草 (NPKS) 3 个处理的土壤,设置施肥与不施肥盆栽试验,监测水稻产量、土壤基础地力产量和基础地力贡献率、水稻氮磷钾养分吸收量、氮磷钾养分利用效率,分析氮、磷、钾利用效率对土壤基础地力贡献率的响应。 【结果】 早晚稻土壤基础地力产量和基础地力贡献率三个处理土壤大小顺序均为 NPKS > NPK > CK,NPKS 处理土壤早晚稻两季平均基础地力产量和基础地力贡献率较 CK 处理土壤分别增加 113.8% 和 93.7%,NPK 处理分别增加 100.7% 和 81.9%。在同一施肥水平条件下,早、晚稻均以土壤基础地力较高的 NPKS 处理氮、磷、钾肥偏生产力,土壤养分依存率,氮、磷、钾素收获指数较高,氮、磷、钾肥回收利用率,肥料农学效率,肥料对产量的贡献率则较低。回归分析表明,氮、磷肥回收利用率,氮、磷、钾肥农学效率,氮、钾素生理利用率均随土壤基础地力贡献率的提高呈显著或极显著降低;氮、磷、钾肥偏生产力,氮、磷、钾素土壤依存率随土壤基础地力贡献率的提高呈显著或极显著提高。 【结论】 长期施氮磷钾肥或长期氮磷钾肥配施稻草均能提高土壤基础地力,以长期氮磷钾肥配施稻草的效果更显著。在较高基础地力土壤上生产,可以在保证作物高产稳产的情况下实现减量化施肥,实现农业生产的可持续性。      

Integrated nutrient management (INM) on yield trends and sustainability,nutrient balance and soil fertility in a long-term (30 years) rice-wheat system in the Indo-Gangetic plains of India

We analyzed data from a long-term rice–wheat cropping sequence to evaluate the effects of integrated nutrient management (INM) on yield trends and sustainability, nutrient balance and soil fertility of the system. After 30th cycle, grain yield of both the crops significantly declined under control and highest rice and wheat grain yields were obtained when 50% N supplied through green manure and farm yard manure, respectively. The magnitude of yield slope under INM was found considerably higher than 100% recommended fertilizer (RDF). Sustainable yield index (SYI) for both the crops were found lower in control but considerably higher with the 100% RDF and under INM. The soils under all the treatments suffered an apparent loss of K and N (except where organics replacing 50% N). Correlation study also reveals K is the sole factor for the yield sustainability as apparent K balance was negatively correlated with SYI and yield slope.     

长期不同施肥下杂交稻与常规稻的产量与土壤养分平衡

肥料长期定位试验设在浙江金华市农业科学研究所和金华市石门农场。试验设6个肥料处理和2个品种对比处理。结果表明,水稻产量与土壤养分供应能力和养分吸收量紧密相关;缺肥处理的土壤养分为负值,其它各处理N和P都有积累。随着连续种植水稻,缺肥区土壤所缺养分的耗损速度与试验前土壤该种养分状况和种植水稻品种有关;杂交稻的总产量平均比常规稻增加10.8%,氮、磷、钾总量分别平均比常规稻增加5.2%、8.8%、12.8%,对土壤中养分消耗比常规稻强。在种植水稻的养分管理中,必须考虑种植前的土壤养分状况以及施肥和种植不同水稻品种对土壤养分平衡的中长期效应。     

缺苞箭竹密度对叶片养分动态和养分利用效率的影响

The monthly dynamics of nitrogen (N) and phosphorus (P) concentrations and stocks in leaves, resorption efficiency, and resorption proficiency as well as leaf-level use efficiency, nutrient productivity, and mean residence time were studied to understand the effect of stem density of dwarf bamboo (Fargesia denudata Yi) on leaf-level N and P use efficiency in three dwarf bamboo stands with different stem densities under bamboo-fir (Picea purpurea Mast.) forest over one growing period in the Wanglang National Nature Reserve, Sichuan, China. Dwarf bamboo density had little effect on the dynamics pattern of both N and P concentrations, stocks, resorption efficiency, and resorption proficiency, but strongly affected their absolute values and leaf-level use efficiency. Higher density stands stored more nutrients but had lower concentrations. There was a clear difference in the resorption of limiting nutrient (N) and non-limiting nutrient (P) among the stands. Phosphorus resorption efficiency, N resorption proficiency, and P resorption proficiency increased with increase of stem density, but no significant variation of N resorption efficiency was found among the stands. Moreover, the higher density stands used both N and P more efficiently with higher N productivity and higher P mean residence time, respectively. Higher P productivity was found in the lower density stands, but there was no clear variation in the N mean residence time among stands. These suggested that the higher density stands may have more efficient strategies for utilizing nutrients, especially those which are limiting.     

System productivity,nutrient use efficiency and apparent nutrient balance in rice-based cropping systems

A 2-year field experiment was conducted to assess system productivity, nutrient use efficiency and apparent balances of phosphorus (P) and potassium (K) in diversified rice-based cropping systems at Gazipur, Bangladesh. Four cropping systems: wheat–fallow–rice, maize–fallow–rice, potato–fallow–rice and mustard–fallow–rice in main plots and four nutrient combinations: NPK, NK, NP and PK in sub-plots were arranged in a split-plot design with three replications. Receiving the NPK treatment, all the component crops gave the highest yield, and omission of N from fertilizer package gave the lowest yield. The maize–rice system removed the highest amount of N (217 kg ha^?1), P (41 kg ha^?1) and K (227 kg ha^?1) followed by wheat–rice, potato–rice and the least in mustard–rice system. The wheat–rice and maize–rice system showed negative K balance of –35.5 and –60.4 kg ha^?1 in NPK treatment, while potato–rice system showed a positive K balance of 31.0 kg ha^–1 with NPK treatment. The N, P and K uptake and apparent recovery by the test crops may be used for site-specific nutrient management. The K rates for fertilizer recommendation in wheat and maize in Indo-Gangetic plain need to be revised to take account for the negative K balance in soil.     

施氮水平对杂交晚粳“浙优12”产量及氮素利用效率的影响

为探讨杂交粳稻"浙优12"最佳施氮量,采用田间试验研究了不同施氮水平对浙北平原黄松田水稻产量和氮素利用率的影响。结果表明,水稻产量、氮肥生理效率(PEN)、氮肥回收率(REN)均以施氮量210 kg/hm2处理最高,分别比无氮肥区提高了54.4%、34.1 kg/kg和58.6%;与无氮肥区相比,在施N 150 kg/hm2基础上,配施适量有机肥有助于提高氮素利用率和产量,其PEN和REN分别提高33.1 g/g和50.6%,水稻增产61.2%。本试验条件下,综合稻谷产量、生态效应和经济效益三项因素,合理的水稻施氮量为N 234.8～241.0 kg/hm2,相应的经济生态产量为9796.4～9801.9 kg/hm2。     

在施钾条件下灌溉水稻的养分吸收和利用效率研究

Potassium is one of the most important nutrients for rice production in many areas of Asia, especially in southeast China where potassium deficiency in soil is a widespread problem. Field experiments were conducted for four consecutive years in Jinhua City, Zhejiang Province, to determine utilization of nutrients (N, P and K) by inbred and hybrid rice and rice grain yields as affected by application of potassium fertilizer under irrigated conditions. Grain yield and nutrient harvest index showed a significant response to the NPK treatment as compared to the NP treatment. This suggested that potassium improved transfer of nitrogen and phosphorus from stems and leaves to panicles in rice plants. N and P use efficiencies of rice were not strongly responsive to potassium, but K use efficiency decreased significantly despite the fact that the amount of total K uptake increased. A significant difference between varieties was also observed with respect to nutrient uptake and use efficiency. Hybrid rice exhibited physiological advantage in N and P uptake and use efficiency over inbred rice. Analysis of annual dynamic change of exchangeable K and non-exchangeable K in the test soil indicated that non-exchangeable K was an important K source for rice. Potassium application caused an annual decrease in the concentration of available K in the soil tested, whereas an increase was observed in non-exchangeable K. It could be concluded that K fertilizer application at the rate of 100 kg ha^-1 per season was not high enough to match K output, and efficient K management for rice must be based on the K input/output balance.     

水稻氮素利用效率的研究进展及其动向

本文综述了国内外有关水稻基因型、根系生长、物质积累、生理代谢、植株性状与氮素利用效率关系的研究进展。指出水稻发根力强、根系发达的品种有利于提高对土壤氮素的吸收能力;分蘖力强,齐穗期粒叶比大,抽穗后干物质积累量大,库容量大,结实率、千粒重、生物产量和收割指数高的品种对氮素的利用效率高;其生理学特征表现为硝酸还原酶、谷氨酸合成酶和RuBP羧化酶的活性高。总结了从氮肥种类与平衡施肥、施肥方法与肥水运筹、氮肥精准施用技术方面提高稻田氮肥利用率的有效途径。提出了提高水稻氮效率的研究重点,即建立水稻氮素效率间接评价的有效方法、突出水稻氮素效率的遗传规律与品种选育工作、协调氮素高效吸收与高效利用矛盾的栽培策略和深化以叶色为基础的高效定量施氮技术研究4个方面。     

Role of crop diversification and integrated nutrient management in resilience of soil fertility under rice-wheat cropping system

A field study conducted for two crop cycles of five cropping systems supplied with six nutrient combinations at the Indian Agricultural Research Institute, New Delhi indicated that the cropping systems having a legume increased organic C content over initial level by 0.02?–?0.05%, available N by 3.5?–?14.1?kg ha^???1, whereas the rice-wheat cropping system resulted in a reduction in organic C and available N over initial level by 0.05% and 1.5?kg ha^???1, respectively after 2 years of study. Rice-potato-mungbean cropping system resulted in a negative balance of available P and rice-clover cropping system had a negative balance of both available P and available K content in soil and thus call for adequate P and K fertilization. Application of P and K helped in building up their content in soil; NPK?+?FYM showed the highest increase in organic C, available N, available P and available K content in soil. These results suggest the inclusion of a legume in a cropping system for maintaining organic C and available N in soil and adequate P and K fertilization for arresting the depletion of available P and K content in soil. Integrated nutrient management is one of the best methods for resilience of soil fertility under rice-wheat cropping system.     

Enhancing nutrient translocation,yields and water productivity of wheat under rice–wheat cropping system through zinc nutrition and residual effect of green manuring

Abstract

Efficient nutrient and water use are two important considerations to obtain good harvests of wheat. This necessitates the development of an effective nutrient management technique that not only increases yield, but simultaneously can save nutrient and water use. In this context, a field experiment was conducted at Indian Agricultural Research Institute, New Delhi, India to evaluate the residual effect of sesbania and rice bean (in-situ), subabul (ex-situ) green manuring and Zinc (Zn) fertilization, using chelated Zn-ethylenediaminetetraacetic acid (Zn-EDTA) on nutrient use, yields and water productivity of wheat under rice–wheat cropping system. Among residual effects of green manure crops and Zn fertilization, sesbania and foliar spray of 0.5% chelated Zn-EDTA at 20, 40, 60 and 80 days after sowing (DAS) recorded significantly higher nutrient content and uptake and yields than other green manure crops and Zn treatments. Residual effect of sesbania saved about 46.5?×?10³ and 30.5?×?10³ L irrigation water per tonne of wheat over subabul and rice bean, respectively. Foliar spray of 0.5% chelated Zn-EDTA at 20, 40, 60 and 80 DAS saved about 55.5?×?10³, 47?×?10³ and 13?×?10³ L irrigation water per tonne wheat over residual effect of 5?kg Zn ha^?1 through chelated Zn-EDTA as soil application, 2.5?kg Zn ha^?1 through chelated Zn-EDTA as soil application + 1 foliar spray of 0.5% chelated Zn-EDTA at flowering and foliar spray of 0.5% chelated Zn-EDTA at active tillering?+?flowering?+?grain filling, respectively. Correlation analysis showed positive correlation between Zn uptake and grain yield.     

Nutrient management and submergence-tolerant varieties antecedently enhances the productivity and profitability of rice in flood-prone regions

Abstract

Poor productivity of rice in rainfed lowlands is due to complete submergence as it is a major abiotic stress of these regions. For enhancing the rice productivity of these areas, better nutrient management options are required and results may even better when combined with stress tolerant cultivars, even when tested under natural conditions of farmers’ field. For supporting the above statement, the effect of nitrogen and phosphorus in graded doses was evaluated for submergence tolerance in controlled conditions and the results obtained were tested and validated at farmers’ field in Cuttack, Odisha, India. Shoot elongation, leaf senescence and lodging were lowest with the application of higher phosphorus (60?kg ha^?1). Highest dose i.e. 100-60-40 NPK kg ha^?1 resulted in higher plant survival of all the varieties by 90–170% over no nutrient application, it was also reflected in the higher growth after recovery, leaf greenness, leaf and stem growth, chlorophyll and carbohydrate concentrations and ultimately higher grain yield. At farmers’ field, application of basal P, K and post-flood N management practice resulted in overall better performance of Swarna and Swarna-Sub1 showing higher yield attributes leading to 65.7 and 37.9% higher grain yield, over conventional practices followed by farmers. Apart from that results were more positive if post-flood nitrogen was applied as urea foliar spray might be due to quick absorption of N by plant leaves and also spraying helps in removing the silt of flood water sticking to the leaf surface and facilitated the plants to photosynthesize and survive after desubmergence. These cost-effective management options may enhance the productivity and profitability of rice in the flood-prone areas where farmers hesitate to apply nutrients.     

长期施用有机肥对水稻产量和氮磷养分利用效率的影响

以长三角地区典型土壤类型青紫泥为背景土壤,研究连续7年有机肥不同施用量和化肥减量条件下水稻产量、氮磷吸收累积特性和氮磷利用效率,并对影响水稻氮磷吸收利用效率的原因进行分析。结果表明,与纯化肥处理相比,施用有机肥处理在不同程度上增加了水稻产量,其中以处理C4(30 t·hm~(-2)有机肥+1/2常量化肥)增加比例最大,为5.67%。当有机肥单施用量达60 t·hm~(-2)时,水稻产量比纯化肥处理增加5.56%,地上部氮磷累积均高于其它各处理,其中,氮累积尤为明显,增加比例为16.5%~25.4%。有机肥不同用量配合化肥减量施用时水稻地上部氮磷转运量、生理利用效率与纯化肥处理间无明显差异。然而,当单施有机肥用量达60 t·hm~(-2)时,氮转运量明显增加,生理利用效率明显降低,磷生理利用效率亦有所降低,但不如氮明显。水稻氮磷生理利用效率降低的主要原因是长期大量施用有机肥使土壤养分含量增加特别明显,可能超过利于水稻利用的浓度范围。另外,土壤矿质元素铵态氮在水稻生长过程中含量过高也与之紧密相关。     

紫云英还田配施化肥对单季晚稻养分利用和产量的影响

研究旨在探讨紫云英较高鲜草翻压量条件下配施不同比例常规用量化肥对单季晚稻养分吸收、养分利用效率和产量的影响。试验设置7个处理:CK(不翻压紫云英和不施化肥),CF(常规用量施肥)及翻压45 t hm-2(GM45)紫云英鲜草配施0、20%、40%、60%和80%常规用量化肥(CF)。在浙江省金华市蒋堂农业科学试验站进行为期2年的田间试验,结果表明,在所有的紫云英翻压配施化肥处理中,虽然水稻N、P、K的总吸收量以GM45+80%CF处理最高,但稻谷P、K养分最高吸收量出现在GM45+40%CF处理中,水稻养分内部利用效率随化肥配施量的增加而降低;水稻的N、P和K的农学利用效率和稻谷产量均以GM45+40%CF处理最高。从提高肥料利用率和降低环境风险的角度出发,紫云英鲜草异地还田量为45 t hm-2时,以配施N 80.6 kg hm-2、P2O521.5 kg hm-2和K2O 43.3 kg hm-2为宜。与CK处理相比,CF和紫云英鲜草翻压配施化肥处理的稻谷产量分别提高13.7%和8.5%～17.4%。在紫云英—单季晚稻耕作制中,紫云英异地还田量45 t hm-2不会使单季晚稻苗期产生僵苗现象。     

Symbiotic parameters,growth, nutrient accumulation,productivity and profitability as influenced by integrated nutrient management in lentil (Lens culinaris)

Field experiments evaluated the effects of integrated nutrient management on symbiotic parameters, growth, nutrient accumulation, productivity and profitability of lentil (Lens culinaris Medikus). Application of recommended dose of nutrients (RDN, 12.5 kg N ha^?1 + 40 kg P₂O₅ ha^?1) + 25 kg ZnSO₄ ha^?1 + seed inoculation with biofertilizers [Rhizobium + phosphate solubilizing bacteria (PSB) + plant growth promoting rhizobacteria (PGPR)] + 1.0 g ammonium molybdate kg^?1 seed recorded the highest number & dry weight of nodules, leghaemoglobin content, root & shoot dry weight, plant height, number of pods plant^?1 and 100-seed weight. The next best treatment was RDN + seed inoculation with biofertilizers + 1.0 g ammonium molybdate kg^?1 seed. On the basis of mean of three-year data, the treatment of RDN + 25 kg ZnSO₄ ha^?1 + seed inoculation with biofertilizers + 1.0 g ammonium molybdate kg^?1 seed proved the best in realizing the highest grain yield (34.0%), gross returns (34.0%) and net returns (54.8% higher over control). Nitrogen, phosphorus and potassium in the grains and straw were significantly improved where RDN was applied in combination with seed inoculation, basal application of ZnSO₄ and seed treatment with 1 g ammonium molybdate than their single applications.     

Dynamic economic management of soil erosion,nutrient depletion,and productivity in the north central USA

Physical scientists have presented a wealth of evidence regarding the effects of cropland soil degradation. Because soil degradation has both on‐site and off‐site effects, public policies have often tried to increase rates of conservation over privately optimal rates. Where private incentives leave off and public incentives start up is somewhat controversial, however. Physical evidence, while necessary, is not sufficient to predict conservation actions by farmers in response to the threat of degradation. This paper provides a partial explanation for why farmers may adopt differing conservation strategies, even though they share similar preferences. A model is constructed that divides soil degradation into reversible and irreversible components. We portray nutrient depletion as a reversible facet of soil degradation and soil profile depth depletion as an irreversible facet of soil degradation. Predictions of optimal management response to soil degradation are accomplished using a closed‐loop model of fertilizer applications and residue management to control future stocks of soil nutrients and soil profile depth. Our model is applied to degradation data from nine soils in the north central United States. Three principal findings result: First, due to differences in initial soil properties, susceptibility to degradation, sensitivity of yield to soil depth, and yield response to alternative management practices, dynamically optimal economic strategies cannot be inferred directly from physical results but are inferred from the associated economic implications. Second, optimal residue management is more variable with respect to soil type than to the erosion phase of the soil, implying that substantial gains to targeting are possible. Third, nutrient depletion is a more compelling motivator for adopting residue management than soil profile depth depletion. This implies that motivating residue management requires programs that pay even greater attention to reversible degradation, and therefore the overall farm management implications, rather than strictly to protect topsoil from irreversible degradation. Copyright © 2001 John Wiley & Sons, Ltd.     

Cropping diversity with rice influences soil aggregate formation and nutrient storage under different tillage systems

Background : The soils under continuous rice monocropping are currently facing a serious threat of accelerated soil and environmental quality degradation. Aims : Examining the impact of tillage and cropping diversity on soil aggregate stability and associated nutrients in a sub‐tropical rice ecosystem. Methods : A split‐plot experiment with tillage (minimum, MT vs. conventional, CT) as a main plot and cropping diversity [mustard (Brassica napus)–rice (Oryza sativa)–rice (M–R–R), wheat (Triticum aestivum)–rice–rice (W–R–R), and lentil (Lens esculenta)–rice–rice (L–R–R)] as a sub‐plot was repeated for four years. Soil aggregate properties were measured using wet sieving techniques. Soil organic carbon (SOC) and nutrients were measured in different aggregate size groups as well as in the bulk soil samples. Results : Results show that all the aggregate size groups were similar in both MT and CT, except in 0.85–0.30 mm. Likewise, cropping diversities increased soil aggregation, being higher aggregate size of < 0.053 mm in M–R–R relative to the W–R–R and L–R–R, where the latter two were alike. By contrast, > 2 mm aggregates were higher in L–R–R than in M–R–R and W–R–R, where the latter two were similar. The MT increased aggregate mean weight diameter (MWD) by 14% in W–R–R, and by 29% in L–R–R. Soil organic carbon (SOC), total N (TN), and available P were higher in MT than in CT, while it was alike for exchangeable K and available S. While W–R–R had a higher aggregate‐associated SOC, available P, and available S, L–R–R had a higher TN, and M–R–R had a higher exchangeable K. While SOC, TN, and exchangeable K accumulated more in the > 0.85 mm size aggregates, the available P, in contrast, accumulated more in < 0.85 mm size aggregates. Conclusion : Wheat–rice–rice diversity, coupled with minimum tillage, has a higher potential for soil fertility sustenance and crop productivity through better nutrient protection.     

Grain yield,nitrogen use efficiency and tillage intensity in wheat as affected by precision nutrient management

ABSTRACT

The present studies were conducted to evaluate the effect of different nutrient management practices under two tillage options in wheat. The experiments were laid out in split-plot design with a combination of two varieties (WH 1105 and HD 2967) and two tillage options (Conventional and No tillage) in the main plot and six precision nutrient management practices [absolute control, site-specific nutrient management with Nutrient Expert for wheat (SSNM-NE)(170 kg nitrogen (N)/ha), SSNM NE+GreenSeeker (GS)(153/158 N kg/ha), N₁₂₀ (120 kg N/ha) before irrigation, N₁₂₀ after irrigation and N Rich (180 kg N/ha)] in subplot replicated thrice. The grain yield and quality characters in no tillage (NT) and conventional tillage (CT) were similar but agronomic efficiency was higher in NT. Both the varieties (WH 1105 and HD 2967) gave similar grain yield and quality. Wheat variety WH 1105 recorded significantly higher sodium dodecyl sulfate sedimentation (SDS) and gluten index. The treatment SSNM NE+GS had resulted in 107.1% higher grain yield than no nitrogen control but similar to enriched N plot (180 kg N/ha). The grain protein, SDS and gluten index in need-based nutrient management (SSNM+GS) treatment were found to be similar as recorded in SSNM-NE (170 kgN/ha) and N enriched plot (180 kg N ha^?1). The agronomic efficiency and recovery efficiency in SSNM+GS were also better than SSNM NE.     

Cropping strategies,soil fertility investment and land management practices by smallholder farmers in communal and resettlement areas in Zimbabwe

Three smallholder villages located in typical communal (from 1948), old (1987) and new (2002) resettlement areas, on loamy sand, sandy loam and clay soils, respectively, were selected to explore differences on natural resource management and land productivity. Focus group discussions and surveys were carried out with farmers. Additionally, farmers in three wealth classes per village were chosen for a detailed assessment of their main production systems. Maize grain yields (t ha⁻¹) in the communal (1·5–4·0) and new resettlement areas (1·9–4·3) were similar but significantly higher than in the old resettlement area (0·9–2·7), despite lower soil quality in the communal area. Nutrient input use was the main factor controlling maize productivity in the three areas (R² = 59–83%), while soil quality accounted for up to 12%. Partial N balances (kg ha⁻¹ yr⁻¹) were significantly lower in the new resettlement (−9·1 to +14·3) and old resettlement (+7·4 to +9·6) than in the communal area (+2·1 to +59·6) due to lower nutrient applications. Averaged P balances were usually negative. Consistently, maize yields, nutrient applications and partial N balances were higher in the high wealth class than in poorer classes. This study found that most farmers in the new resettlement area were exploiting the inherent soil nutrient stocks more than farmers in the other two areas. We argue that effective policies supporting an efficient fertilizer distribution and improved soil management practices, with clearer rights to land, are necessary to avoid future land degradation and to improve food security in Zimbabwe, particularly in the resettlement areas. Copyright © 2009 John Wiley & Sons, Ltd.     

减量施肥下小麦产量、肥料利用率和土壤养分平衡

【目的】我国化肥过量施用现象普遍,不利于生态环境保护和农业可持续生产。研究化肥减量施用对小麦产量、籽粒灌浆和肥料利用率的影响,可以为我国化肥高效施用和零增长目标提供理论依据。【方法】在四川盆地进行了两个大田试验,以习惯施肥 (N、P₂O₅、K₂O 分别为 180、120、45 kg/hm2) 为对照,设置减量施肥 (N、P₂O₅、K₂O 分别为 96、60、45 kg/hm2) 处理,测定了小麦产量及构成、籽粒灌浆、花后干物质转运、旗叶叶绿素含量、养分平衡和肥料利用率。【结果】与习惯施肥相比,减量施肥下小麦产量、穗数、穗粒数没有显著变化,小麦–玉米轮作田块小麦千粒重显著提高 5.8%。根据 Logistics 方程拟合结果,减量施肥显著提高了小麦–玉米轮作田块小麦理论最大千粒重,渐增期、缓增期籽粒净增重,对其他灌浆参数影响不显著。减量施肥下小麦干物质转运量、转运率及其对籽粒灌浆的贡献率增加 28.5%、17.5% 和 20.7%,但花后旗叶叶绿素含量下降速度加快。习惯施肥和减量施肥土壤氮素盈余分别为 22.6 和 –30.2 kg/hm2,土壤磷盈余分别为 80.4 和 22.8 kg/hm2。减量施肥后氮肥偏生产力、农学效率和表观回收率比习惯施肥提高 79.2%、69.1% 和 27.9%,磷肥偏生产力、农学效率和表观回收率提高 91.1%、72.7% 和 68.5%。【结论】本试验的两年时间内,减量施肥可以维持小麦产量,促进小麦干物质转运及其对籽粒灌浆的贡献,但花后功能叶衰退加速。减量施肥下肥料利用率提高,土壤磷素盈余降低,土壤氮素亏缺,需要在确保维持小麦产量、土壤肥力和养分平衡的基础上,继续优化减氮量。     

Soil nutrient status and yield of rice as affected by long-term integrated use of organic and inorganic fertilizers

Nutrient balance is the key component to increase crop yields. Excess and imbalanced use of nutrients has caused nutrient mining from the soil and deteriorated crop productivity and ultimately soil health. Replenishment of these nutrients has a direct impact on soil health and crop productivity. Based on this fact, the present research was conducted to determine the effects of long-term integrated use of organic and inorganic fertilizers on soil nutrient status and yield (grain and straw) in rice. Different combinations of inorganic nitrogen (N) and organic sources (sewage sludge and compost) were applied to the soil. Data revealed that application of mineral NPK in combination with 50% N through compost significantly increased the organic matter content (0.36%), available phosphorus (16.50 kg/ha) and available potassium content (239.80 kg/ha) in soil. The maximum available N (225.12 kg/ha) was found by the substitution of 50% N through sewage sludge. This improvement in soil nutrient status through combined use of organic and inorganic fertilizers produced significant increase in grain and straw yield as compared to inorganic fertilizers alone. Maximum grain (6.96 t/ha) and straw (8.56 t/ha) yields were found in treatment having substitution of 50% N (recommended) through compost @10t/ha. Also, a significant positive correlation was found between soil nutrients and straw and grain yield in rice. Thus the study demonstrated that substitution of 50% inorganic N through compost will be a good alternative for improving soil fertility.