Impact of organic and inorganic nutrition on soil–plant nutrient balance in arecanut (Areca catechu L.) on a laterite soil

The study assessed the impact of continuous application of vermicompost and chemical fertilizers nitrogen, phosphorus and potassium (NPK) on arecanut in India. Key parameters examined were biomass production, nutrient uptake, yield, soil fertility and net benefit. Pooled analysis of 8-year data revealed that nutrient application registered significantly higher yield (2585–3331 kg ha^?1) than no nutrition (1827 kg ha^?1). Yields in organic nutrition were around 85% of the yields obtained in inorganic NPK. The concentrations of leaf N and K were significantly higher with NPK than with vermicompost. Vermicompost significantly increased soil organic carbon and the availability of calcium (Ca), magnesium (Mg), manganese (Mn) and copper (Cu), but reduced exchangeable K in soil. The total uptake of K and Ca together contributed positively to 75% variability in total biomass production. Nutrient removal of iron (Fe), P, K and Cu positively influenced the yield with about 81% variability. Biomass partitioning and nutrient uptake pattern are important for fertilization program of arecanut.     

Studies on method and rate of fertilizer application in apple under mulch in north-western Himalayas

Different methods of fertilizer application-drip fertigation and conventional fertilizer application under drip, surface irrigation, and rainfed conditions were evaluated during 2009–2012 at Krishi Vigyan Kendra, Shimla, India. The experiment was arranged in randomized block design (RBD), replicated thrice. Results suggest that fertigation significantly increased growth parameters over conventional methods. Fruit yield was significantly higher under fertigation (13.7 t ha^?1) over conventional fertilizer application with drip (11.6 t ha^?1), surface irrigation (10.6 t ha^?1), and under rainfed (8.6 t ha^?1). Fruit quality parameters were also superior under fertigation. Fertigation maintained higher available nitrogen (N) and potassium (K) content in 0-30 cm soil layers. Available phosphorus (P) was higher in 0-20 cm soil depths in all the treatments. Fertigation with 80 and 100 percent recommended NPK dose registered statistically comparable results. In addition to higher productivity, fertigation resulted in 20 percent fertilizer savings over drip irrigation and 20 percent fertilizer besides 40 percent water savings over surface irrigation.     

Productivity of capsicum as influenced by fertigation with chemical fertilizers and humic acid

Studies were conducted to evaluate the effect of nitrogen, phosphorus and potassium (NPK) fertigation through drip on nutrient distribution and productivity of capsicum. The experiment was set up in Randomized Block Design with three levels of fertigation (100, 80 and 60% of recommended NPK) without humic acid (sole fertigation) and with humic acid (combined fertigation). Combined fertigation registered lower available N and K and higher available P in deeper soil layers. Fruit yield was 17–27 percent higher under combined fertigation over sole fertigation. Fertilizer use efficiency was higher in combined fertigation. Significantly higher N, P and K uptake was also observed under combined fertigation. Further, growth and yield of capsicum were statistically at par between 100 percent (sole fertigation) and 80 percent recommended NPK dose (combined fertigation). The results, therefore, ensures the partial replacement of chemical fertilizers with more economic and environmentally safe organic materials when applied through drip.     

Impacts of Vermicompost and Nitrogen,Phosphorus, and Potassium Application on Soil Fertility Status in Arecanut Grown on a Laterite Soil

A field experiment (1998 to 2010) investigated the effects of vermicompost (VC) and chemical fertilizer (CF) application alone or in combination on soil fertility status in arecanut. Vermicompost significantly increased the soil pH (6.3) over CF and integrated treatments (5.7–5.8). Greater soil organic carbon was noticed with VC (2.85–3.00%) than with CF (1.72–1.89%) and VC + CF (1.89–2.55%) in 2009. Soil test phosphorus (P) (mg kg^–1) significantly increased with VC 200% nitrogen (N) equivalency (35.3) compared to other treatments (8.5–23.3) at the 0- to 30-cm depth in 2009. In 2003, soil test potassium (K) (mg kg^–1) was significantly greater with CF at depths of both 0–30 cm (162–187) and 30–60 cm (172–214) than VC and control. Soil test K depleted with VC application in 2009. Application of VC significantly improved soil test calcium (Ca) and magnesium (Mg) compared to CF, CF + VC, and control at 0–30 cm deep. Soil test values for micronutrients increased in 2009 compared to initial status.     

有机物料与化肥配施提高黄泥田水稻产量和土壤肥力

农业有机物料具有资源化再利用的特点,与化肥配施既可以保证作物产量,也可以提升地力。为了建立最适宜的南方低产黄泥田培肥模式,该文在浙江金衢盆地开展3年田间试验研究化肥与不同有机物料(菇渣、紫云英、牛粪和秸秆)配施对水稻产量和土壤肥力的影响。结果表明:1)有机物料与化肥配施可以显著提高水稻产量,化肥+菇渣、化肥+紫云英、化肥+牛粪和化肥+秸秆处理下,水稻三年的平均产量分别比单施化肥提高了9.7%、9.5%、12.3%和9.5%;2)有机物料与化肥配合施用,土壤有机质、土壤养分(全氮、有效磷、速效钾和CEC)及土壤容重较单施化肥处理有一定程度的改善,其中,化肥+牛粪效果最明显,有机质质量分数提高了12.5%,土壤有效磷质量分数提高了37.7%,CEC提高了16.1%;3)与单施化肥相比,化肥+菇渣、化肥+牛粪处理下5 mm机械稳定性大团聚体分别提高了10.4%和6.7%,各配施处理均显著降低了团聚体破坏率。总得来讲,连续三年有机物料与化肥配施较单施化肥处理提高了水稻产量、改善了土壤肥力状况、增加了土壤团聚体稳定性,其中又以牛粪与化肥配合施用效果最佳。     

Optimum plant stand and nutrient doses for summer groundnut under check basin irrigation and drip fertigation in light black soils of peninsular Western India

Abstract

A field experiment was conducted at Research Farm of ICAR-Directorate of Groundnut Research, Junagadh for consecutive three summer seasons of 2013, 2014, and 2015 with the objectives of identifying optimum plant density and nutrient doses under check basin irrigation and drip fertigation for higher productivity and net returns. The treatments were; three plant densities viz., 3,33,333 plants/ha (100% of recommended plant density; P1); 4,16,666 plants/ha (125% of recommended plant density; P2), and 4,99,999 plants/ha (150% of recommended plant density;P3) in main plots, and three nutrient doses viz., 18.75–37.5–22.5 NPK kg ha^?1 (75% of recommended nutrient dose; F1), 25-50-30 NPK kg ha^?1 (100% of recommended nutrient dose; F2), and 31.25–62.5–37.5 NPK kg ha^?1 (125% of recommended nutrient dose; F3) in sub-plots, and replicated thrice. The same sets of treatments were tested under both check basin irrigation and drip fertigation. The data were analyzed using split plot design. Pod yield, haulm yield, and net returns were significantly higher with P3 as compared to P1 under check basin irrigation but only haulm yield was found significantly higher with P3 under drip fertigation. Under check basin irrigation, NH₄–N, NO₃–N, and available P and K in soil were found in the order P1?>?P2?>?P3 (p?<?0.05) while in case of drip fertigation, differences were significant only for available K which was significantly higher in P1 over both P2 and P3. Under check basin irrigation, F2 i.e., application of 100 percent of recommended nutrient doses, being at par with F3, significantly improved pod yield, haulm yield and net returns over that with F1 however, differences were not significant under drip fertigation. NH₄–N, NO₃–N and available P and K in soil under both the irrigation systems were in the order F3?>?F2?>?F1 (p?<?0.05).     

长期施肥对黄壤有机碳平衡及玉米产量的影响

基于长期定位试验,以黔中典型黄壤为研究对象,采用单因素方差分析、可持续性指数、稳定性指数等方法对长期定位试验获取的数据进行分析和比较,以探讨长期不同施肥处理对黄壤有机碳含量、有机碳平衡量、玉米产量稳定性、可持续性及其相互关系的影响。结果表明:(1)与施化肥和对照处理相比,施有机肥处理土壤有机碳含量明显升高,按大小排序依次为:MMNPK1/2M+1/2NPK1/4M+3/4NPK;(2)施有机肥处理黄壤有机碳平衡量为正值,且随有机肥施用量增加而增加,相反,施化肥和对照处理均为负值,大小依次为:MNPK、M1/2M+1/2NPK1/4M+3/4NPKNPKNKNPN、CKPK,各处理差异显著;(3)有机肥与化肥配施、有机肥单施及氮磷钾化肥协调施用更有利于提高玉米产量,排序为:MNPK1/4M+3/4NPK、1/2M+1/2NPKNPK、MNPNK、PK、NCK;(4)适量有机肥与化肥配施可提高玉米产量稳定性和可持续性(可持续性指数0.6,变异系数0.3),其中,1/4M+3/4NPK处理玉米产量稳定性和持续性最好;(5)玉米年产量与黄壤有机碳平衡量相关度较高,而玉米可持续性、稳定性则主要受有机碳含量影响。综上,有机肥与化肥配施有利于黄壤有机碳含量提升、玉米维持高产稳产。按适量"减肥"原则,以25%有机肥配施75%氮磷钾化肥效果最佳。     

Long-Term Effect of Lime,Mycorrhiza, and Inorganic and Organic Sources on Soil Fertility,Yield, and Proximate Composition of Sweet Potato in Alfisols of Eastern India

A field experiment was conducted for five kharif seasons (2006–2011) in an Alfisol to study the effect of integrated use of lime, mycorrhiza, and inorganic and organics on soil fertility, yield, and proximate composition of sweet potato. Application of graded doses of nitrogen, phosphorus, and potassium (NPK) significantly increased the mean tuber yield of sweet potato by 44, 106, and 130 percent over control. Green manuring along with ½ NPK showed greater yield response over that of ½ NPK. The greatest mean tuber yield was recorded due to integrated application of lime, farmyard manure (FYM), NPK, and MgSO₄ (13.69 t ha^?1) over the other treatments. Inoculation of mycorrhiza combined with lime, FYM, and NPK showed a significant yield response of 10 percent over FYM + NPK. Conjunctive use of lime, inorganics, and organics not only produces sustainable crop yields but also improve soil fertility, nutrient-use efficiency, and apparent nutrient recovery in comparison to NPK and organic manures.     

Is the Period of 18 Years Sufficient for an Evaluation of Changes in Soil Organic Carbon under a Variety of Different Soil Management Practices?

The influence of differing soil management practices on changes seen in soil organic carbon (SOC) content of loamy Haplic Luvisol was evaluated. The field experiment included two types of soil tillage: 1. conventional tillage (CT) and 2. reduced tillage (RT) and two treatments of fertilization: 1. crop residues with nitrogen, phosphorus, and potassium (NPK) fertilizers (PR+NPK) and 2. NPK fertilizers (NPK). The results of SOC fluctuated from 9.8 to 14.5 g kg^?1 and the tillage systems employed and fertilization status did not have a statistically significant influence on SOC. The SOC content was higher in RT (12.4 ± 0.86 g kg^?1) than in CT (12.2 ± 0.90 g kg^?1). On average, there was a smaller higher value of SOC in PR+NPK (12.4 ± 1.02 g kg^?1) than in NPK (12.3 ± 0.88 g kg^?1). During a period of 18 years, reduced tillage and application of NPK fertilizers together with crop residues build up a SOC at an average speed of 7 and 16 mg kg^?1 year^?1, respectively, however conventional tillage and NPK fertilizer applications caused a SOC decline at an average speed of 104 and 40 mg kg^?1 year^?1, respectively.     

Effect of Drip Fertigation With and Without Mulch on Soil Hydrothermal Regimes,Growth, Yield,and Quality of Apple (Malus domestica Borkh)

Studies were undertaken to investigate the effect of drip fertigation and conventional fertilizations with and without mulch on the productivity of apple. Soil moisture under fertigation remained greater in the upper 0–30 cm of soil, whereas under conventional surface irrigation, deeper layers registered greater values. Mulch application resulted in 2–4% greater moisture and raised the minimum but lowered the maximum soil temperatures, especially during later growth periods. Available nitrogen (N) and potassium (K) contents under fertigation closely followed the moisture distribution pattern. Irrespective of treatments, available phosphorus (P) remained confined within upper 0- to 20-cm soil depth. Fertigation resulted in 35% greater growth and yield over conventional fertilization with irrigations besides saving 25% in irrigation water. Joint use of fertigation and mulch resulted in comparable growth and yield as unmulched condition and saved 20% in fertilizers and 15% in irrigation water.     

沼液化肥配施对芦笋地土壤肥力及芦笋品质的影响

针对芦笋种植过程中大量化肥长期施用所造成的土壤肥力退化和芦笋品质下降的问题，以沼液有机替代化肥来研究相同氮磷钾养分施用的前提下，沼液不同用量替代化肥施用对芦笋地土壤肥力及芦笋品质的影响。试验设不施肥处理（CK）、常规施肥处理（NPK）、沼液全氮替代化肥施氮质量25%、50%、75%和100%的处理，共6个处理，分析了沼液替代化肥施用条件下，沼液不同用量对土壤理化性质、微生物量、酶活性、重金属含量及芦笋品质的影响。结果表明：与常规施肥（NPK）处理相比，沼液替代化肥用量≥50%的处理显著增加了土壤有机质的质量分数32.7%～41.5%(P<0.05)，但其对土壤全氮、全磷和全钾质量分数无显著影响（P>0.05）；同时，沼液替代量75%和100%的处理显著提高土壤pH值0.72和1.0，并显著提高土壤速效钾质量分数48.6%和48.8%(P<0.05)，而其对土壤碱解氮和有效磷质量分数没有显著影响（P>0.05）。与不施肥（CK）处理相比，常规施肥、沼液替代化肥施用各处理均能增加土壤蔗糖酶的活性，但沼液替代化肥用量≥50%的处理均显著降低了土壤酸性磷酸酶的活性（P&...     

长期施肥棕壤团聚体分布及其碳氮含量变化

【目的】探究玉米-玉米-大豆轮作体系不同施肥处理对土壤团聚体分布及其有机碳、全氮的影响,以期深入了解施肥对土壤培肥、改善土壤结构的机制。【方法】选取不施肥（CK）,化肥（NPK）,低量有机肥（M1）,低量有机肥与化肥配施（M1NPK）,高量有机肥（M2）,高量有机肥与化肥配施（M2NPK）6个处理。采集棕壤37年长期定位试验微区不同施肥处理的0-20 cm和20-40 cm土样,分析其水稳性团聚体（ 1 mm、1~0.5 mm、0.5~0.25 mm、0.25~0.053 mm及 0.053 mm）分布及其有机碳、全氮分配特征。【结果】棕壤长期施肥对团聚体分布及其碳氮的影响0-20 cm大于20-40 cm,随土层深度的增加,有机碳（SOC）、全氮（TN）含量减少。各处理团聚体及碳、氮在团聚体中的分配主要在黏粉粒中（40%以上）。与CK相比,NPK处理显著提高了黏粉粒的含量,降低大团聚体与微团聚体含量,显著增加黏粉粒储碳比例;M1、M2处理显著增加 1 mm团聚体数量及其SOC含量,显著增加 0.25 mm各粒级团聚体的储碳比例,且M2处理显著高于M1处理;M1NPK、M2NPK处理也显著增加 1 mm团聚体数量及其SOC含量,M1NPK与M2NPK处理在NPK处理的基础上依次增加0.5~0.25 mm（M1NPK）、1~0.5 mm及 1 mm团聚体的储碳比例,M2NPK处理 0.25 mm团聚体储碳比例最高,土壤团聚体全氮的变化趋势与有机碳类似。【结论】棕壤连续有机无机配合施用可显著增加土壤大团聚体数量、SOC、TN含量及其储碳、氮比例,是提高土壤质量、改善土壤结构的有效施肥措施。     

长期施肥对红壤旱地土壤活性有机碳和酶活性的影响

以江西进贤长期肥料定位试验为平台,研究了红壤旱地不同施肥措施对土壤微生物生物量、活性有机C、C库管理指数以及土壤酶活性的影响。研究结果表明:与不施肥和单施化肥土壤相比,施有机肥处理土壤的pH、CEC、有机C、全N、全P、无机N、速效P、速效K及土壤微生物生物量均显著增加,土壤活性有机C和C库管理指数也较试前土壤和其他处理土壤明显提高,此外,土壤的转化酶、脱氢酶、脲酶和酸性磷酸酶活性也较其他处理显著增加。土壤微生物生物量、活性有机C以及4种土壤酶活性之间的相关关系显著,且它们均与土壤有机C、全N、全P、无机N、速效P等土壤养分呈显著正相关。因此,红壤旱地通过长期施用有机肥或与无机肥配施,不仅能显著提高土壤有机质的数量和质量,而且能增加土壤微生物生物量和酶活性,从而显著提高土壤肥力和土壤持续生产力。     

玉米秸秆源有机物料对黑土养分有效性与酶活性的提升效应

  【目的】  研究以玉米秸秆为主要原料制备的不同类型有机物料对东北黑土土壤肥力和玉米产量的影响,为黑土地保护和秸秆资源高效利用提供理论依据。  【方法】  田间定位试验连续进行了5年。试验设不施肥对照 (CK)、单施化肥 (NPK)、化肥配施秸秆 (NPK+ST)、化肥配施生物炭 (NPK+BR) 以及化肥配施堆肥 (NPK+CP) 5个处理,各有机物料每年均为等碳量投入 (C 3200 kg/hm2)。5年后,采集耕层 (0—20 cm) 和亚耕层 (20—40 cm) 土壤样品,测定土壤有机碳 (SOC)、活性有机碳 (LOC)、速效养分与酶活性,并结合年际间玉米产量变化进行综合评价。  【结果】  与NPK相比,NPK+BR处理显著增加了耕层及亚耕层SOC含量,增幅分别为28.2%和11.2%;NPK+CP和NPK+ST处理增加了耕层SOC含量,增幅分别为15.5%和7.6%,对亚耕层SOC含量影响不显著;配施有机物料处理显著增加了0—40 cm土层LOC含量,且NPK+CP和NPK+ST处理LOC含量在0—20 cm土层显著高于NPK+BR,增幅分别为13.2%和8.7%,各种有机物料处理LOC含量在20—40 cm土层差异不显著;3个配施有机物料处理均显著增加了0—20 cm土层有效磷含量,仅NPK+CP和NPK+BR处理显著提高了20—40 cm土层有效磷含量;配施有机物料处理对0—40 cm土层土壤速效氮和速效钾含量影响均不显著,但配施堆肥处理0—20 cm土层土壤速效氮含量显著高于配施秸秆和生物炭处理。配施有机物料处理比NPK处理显著增加了0—40 cm土层土壤纤维素酶、蔗糖酶和磷酸酶活性。NPK+ST和NPK+BR处理比NPK+CP处理更利于提高耕层纤维素酶活性,NPK+ST处理耕层蔗糖酶活性显著高于NPK+BR和NPK+CP处理;配施有机物料处理亚耕层土壤纤维素酶和蔗糖酶活性差异不显著。NPK+ST和NPK+CP处理较NPK+BR处理显著提高了0—40 cm土层土壤磷酸酶活性。不同处理玉米产量在年际间波动变化,配施有机物料处理玉米产量高于NPK处理,NPK+CP和NPK+ST处理对玉米产量的提升在第一年即有明显效果,而NPK+BR处理对玉米产量的积极效果在4年后才表现出来。各处理平均玉米产量的高低表现为NPK+CP > NPK+ST > NPK+BR > NPK > CK。  【结论】  化肥配施生物炭对0—40 cm土层土壤有机碳的积累作用最突出,而配施秸秆和堆肥更利于提升土壤活性有机碳的含量。配施堆肥0—20 cm土层土壤速效氮含量显著高于配施秸秆和生物炭处理,三者0—20 cm土层土壤有效磷含量无显著差异,但配施堆肥和生物炭20—40 cm土层有效磷含量显著高于配施秸秆处理。配施秸秆或生物炭增强了0—40 cm土层土壤纤维素酶活性,而蔗糖酶和磷酸酶活性以配施秸秆和堆肥处理为最高。随着土壤肥力的提高,配施有机物料处理促进了玉米产量的提升,以配施堆肥处理对玉米平均产量的增加幅度最高。因此,对于基础肥力较高的黑土而言,生物炭还田可实现黑土有机碳的快速提升,而堆肥和秸秆直接还田对玉米产量的促进作用更为明显。     

Role of Nutrient Imbalance on Yellow Leaf Disease in Smallholder Arecanut Systems on a Laterite Soil in India

On-farm trials in India investigated the role of nutrient imbalance on yellow leaf disease (YLD) in arecanut on a laterite soil using compositional nutrient diagnosis (CND) approach. Soil fertility status was imbalanced with high organic carbon status and low phosphorus (P) and potassium (K). The CND norms indicated that the order of nutrient demand was changed with nutrient application. Interventions increased yield by 50% during 2007–2010. The correlations indicated positive effect of nitrogen (N) and K and negative effect of manganese (Mn) on yield. The CND indices for NPK were important discriminators between yellowed and apparently healthy populations both in 2007 and 2010. Linear regressions between leaf nutrient concentrations and CND indices were significant for P, K, iron (Fe), Mn, and copper (Cu) (R² = 0.44–0.53). Results suggest that the predisposing factor for YLD might be nutrient imbalance in the soil leading to deficit of major nutrients in plant.     

施肥对土壤有机碳含量及碳库管理指数的影响

在华北夏玉米生产体系中,采用田间试验,研究了不同施肥措施下（不施肥、单施有机肥、推荐施肥、习惯施肥和单施化肥）,土壤有机碳含量、活性有机碳含量和碳库管理指数的变化。结果表明:与不施肥相比,单施有机肥土壤有机碳和活性有机碳含量分别增加 11.68%,21.71%。推荐施肥和习惯施肥土壤有机碳含量分别增加 6.57%,7.58%,活性有机碳含量分别增加 8.53%,4.26%。单施化肥土壤有机碳与活性有机碳含量均没有显著增加;施有机肥和推荐施肥土壤碳库管理指数比不施肥分别高 31.79,13.01。单施化肥土壤碳库管理指数没有显著变化;土壤活性有机碳与总有机碳、碳库管理指数、玉米子粒产量均存在极显著相关关系。碳库管理指数与玉米子粒产量极显著相关,能够指示土壤生产力的变化。可见在当地土壤肥力条件下,施有机肥或有机无机适当配施能提高土壤有机碳含量和土壤碳库管理指数,有利于改善土壤质量,提高土壤肥力。     

Fertigation of humic substances improves yield and quality of broccoli and nutrient retention in a sandy soil

There is lack of information available concerning the effect of humic substances (HS) applied via fertigation on plant growth in sandy soils. Therefore, a field experiment was carried out at El‐Saff district (20 km southwest of Cairo), Egypt, to investigate the role of HS fertigation on water retention of a sandy soil, yield and quality of broccoli (Broccoli oleracea L.) as well as on soil nutrient concentration retained after harvest. The experiment consisted of six fertigation treatments (50%, 75%, and 100% of the recommended NPK‐fertilizer rate for broccoli combined with and without HS application at 120 L ha^–1) in a complete randomized block design with three replicates. Humic substances affected spatial water distribution and improved water retention in the root zone. Furthermore, application of HS increased total marketable yield and head diameter of broccoli as well as quality parameters (i.e., total soluble solids, protein, and vitamin C). Higher nutrient concentrations were found in the broccoli heads and concentrations of plant‐available nutrients in soil after harvesting were also higher, indicating an improvement in soil fertility. In conclusion, HS fertigation can be judged as an interesting option to improve soil water and nutrient status leading to better plant growth.     

Effects of organic fertilizers on yam productivity and some soil properties of a nutrient-depleted tropical Alfisol

Field experiments were conducted at Owo, southwest Nigeria to select organic fertilizer treatments most suitable for sustaining high soil fertility and yam productivity on a nutrient-depleted tropical Alfisol. Eight organic fertilizer treatments were applied at 20 t ha^?1 with a reference treatment inorganic fertilizer (NPK 15–15–15) at 400 kg ha^?1 and natural soil fertility (control), laid out in a randomized complete block design with three replications. Results showed that organic fertilizers significantly increased (p = 0.05) tuber weight and growth of yam, soil and leaf N, P, K, Ca and Mg, soil pH and organic C concentrations compared with the NSF (control). The oil palm bunch ash + poultry manure treatment increased tuber weight, vine length, number of leaves and leaf area of yam by 66, 25, 21 and 52%, respectively, compared with inorganic fertilizer (NPK) and 37, 22, 19 and 44%, respectively, compared with poultry manure alone. Sole or mixed forms of organic fertilizers showed significant improvement in soil physical conditions compared with IF (NPK) and NSF (control). Synergistic use of oil palm bunch ash + poultry manure at 10 t ha^?1 each was most effective for sustainable management of soils and for improving agronomic productivity of yam.     

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。     

Efficient Use of Water and Nutrients Through Drip and Mulch in Apple

Fertigation offers vast potential for efficient use of water and nutrients in sustainable orchard management. Beside minimizing losses, their distribution within the rhizosphere is of utmost importance. In present investigations, most of feeder roots were observed within 30 cm soil depth. Under drip fertigation, wetting front extended horizontally up to 45 cm from emitter. However, the maximum moisture content remained confined within 30 cm distance. Vertically, soil moisture also remained higher in the 0–30 cm soil layers. Under surface irrigation, deeper soil layers registered higher moisture content. Available nitrogen (N) and potassium (K) under fertigation closely followed the moisture distribution pattern. Fertigation plus mulch resulted in 20% fertilizer and 15% water savings over fertigation without mulch. Beside 33% higher fruit yield and 25% water savings, and fertigation plus mulch resulted in 20 percent fertilizer and 40% water savings over surface irrigation.