NUTRIENT UPTAKE KINETICS OF CLOUDBERRY

Mineral fertilization of cloudberry (Rubus chamaemorus) has been inconclusive so far. Nutrient absorption of cloudberry was studied by solution depletion 1) to characterize its nutrient uptake kinetics and 2) to determine its preferred nitrogen (N) form. Two accessions, ‘Fjordgull’ (a female cultivar from Norway) and a local wild clonal selection from ‘Baie-Comeau’ (Canada) were tested. Ammonium (NH₄) and phosphorus (P) absorption presented a two-component kinetic while nitrate (NO₃), potassium (K), and glycine absorption was better fitted with the Michaelis-Menten equation alone. Cloudberry preferences for nitrogen form were in the order: NH₄-N, glycine, NO₃-N. ‘Fjordgull’ exhibited much higher K_m and J_max for P uptake than the ‘Baie-Comeau’ accession, but they exhibited similar NH₄-N uptake kinetics. However, K_m values for all nutrients tested except NH₄-N were higher than reported for other species. Cloudberry does not appear to have evolved efficient absorption kinetics to compensate for the overall very low abundance of nutrients of peatlands.     

NITROGEN UPTAKE AND RECOVERY FROM N FERTILIZER AND LEGUME CROPS IN WETLAND RICE MEASURED BY 15N AND NON-ISOTOPE TECHNIQUES

Intensive rice-based cropping systems rely on nitrogenous fertilizer for optimum grain production and legume crops could be used as an alternative nitrogen (N) source for rice. We investigated the fate of N applied to dual cropping wetland rice in the form of legume residue and ¹⁵N labeled fertilizer. In 2001–2002, hairy vetch and broad bean accumulated 131 and 352 kg N ha^?1 of which 41 and 78% was derived from N₂ fixation. In 2002–2003, hairy vetch accumulated 64 kg N ha^?1 and broad bean accumulated 320 kg N ha^?1 of which 21 to 24% was derived from hairy vetch and 31 to 82% N was derived from broad bean by N difference and ¹⁵N-natural abundance method. Our results reveal that hairy vetch and broad bean can supply 50–100% of N required for intensive wetland rice and can be a viable alternative N source to enhance soil fertility.     

EFFECTS OF PERENNIAL PEANUT AND COMMON BERMUDAGRASS ON NITROGEN AND WATER UPTAKE OF YOUNG CITRUS TREES

A greenhouse experiment was conducted using a Soil-N Uptake Monitoring (SUM) system to determine nitrogen (N) and water uptake dynamics of citrus (CIT), perennial peanut (PP) (Arachis glabrata Benth), and common bermudagrass (BG) (Cynodon dactylon L.) over time. We also assessed the competition for water and N uptake between citrus and groundcover species and compared citrus N uptake measured using the SUM system with the ¹⁵N method. Nitrogen uptake followed cyclic patterns and was greatest for bermudagrass-based systems, while values were similar for PP and citrus systems. Competition for N uptake did occur during the summer months between citrus and BG, while no obvious competition for N uptake occurred between citrus and PP. Water uptake was greatest for the mixed systems and BG monoculture. Citrus, PP, and BG competed for water during the spring and summer seasons. None of the groundcovers significantly affected overall citrus tree growth. Nitrogen use efficiency was greatest for mixed systems and bermudagrass.     

NITROGEN,PHOSPHORUS, AND POTASSIUM NUTRIENT EFFECTS ON GRAIN FILLING AND YIELD OF HIGH-YIELDING SUMMER CORN

A three-site-year field experiment was conducted to determine nitrogen (N), phosphorus (P), and potassium (K) fertilizer effects on grain filling dynamics and yield formation of high-yielding summer corn (Zea mays L.) in a wheat (Triticum aestivum L.)-corn double crop cropping system. Application of combined NPK fertilizers resulted in the greatest grain yield, largest grain number and grain weight when compared with the treatments receiving N, NP, or NK. Grain filling rate and duration, grain volume, and grain yield increased with NPK rates; however, doubling the rate of 180 kg N ha^?1, 40 kg P ha^?1, and 75 kg K ha^?1 fertilizer only led to minimal increases in grain filling rate (0.8%), grain filling duration (1.6%), grain volume (1.3%) and grain yield (0.4%). Our results suggested that for the high-yielding summer corn, a combined NPK fertilization is required to enhance grain filling and yield, and that under well-fertilized circumstances, limited increases in both grain filling and sink capacity might be the main factor restricting further yield improvement.     

土施L-色氨酸对甘蓝产量和养分吸收的影响

本文就土施Ｌ－色氨酸即Ｌ－ＴＲＰ对盆栽甘蓝产量和养分吸收的影响进行了研究。结果表明，在移植前一周土施Ｌ－ＴＲＰ，能明显提高甘蓝产量和干物质积累，并明显促进了甘蓝植株对Ｎ、Ｐ、Ｋ的吸收，提高了Ｎ、Ｐ在球叶中的分配，降低了Ｋ在球叶中的积累。     

NUTRIENT UPTAKE,SOIL AND PLANT NUTRIENT CONTENTS,AND YIELD COMPONENTS OF WHEAT PLANTS UNDER DIFFERENT PLANTING SYSTEMS AND VARIOUS IRRIGATION FREQUENCIES

The effects of seed bed shaping on nutrient variation in soil and plant under two different irrigation intervals were investigated on wheat (Triticum asetivum L.) plants with a split plot design in a field plot in Zahak Agricultural Research Station in Sistan province in 2005. Irrigations after 80 and 160 mm evaporation from class A evaporation pan were used as main plots. Flat surface irrigation, single, triple, and 6-row beds with four replications were subplots. Total soil nitrogen (N), available phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), and sodium (Na) were measured in a 30 cm depth top layer at five sampling times. Shoot samples were analyzed for N, P, K, Ca, Mg and Na. Results showed that the 3-row and the 6-row beds with more frequent irrigation (shorter irrigation interval) increased soil solution sodium content in beds resulting in increased plant sodium absorption. With the 3-row and the 6-row beds, increased solution sodium concentration in soil increased solution ionic strength, dissolution of lime and hence soluble Ca and Mg. With the more frequent irrigation (shorter irrigation interval), only grain nitrogen and sodium contents were increased with no change in the absorption of other nutrients. The shoot N, P, and K uptake with more frequent irrigation (shorter irrigation interval) was greater, however the grain P and K uptakes were similar with the less frequent irrigation (longer irrigation interval), suggesting a lack of transfer from other tissues to grain. The transfer of nitrogen and all other major elements from other tissues to grain was greatest with single row bed with both irrigation intervals, suggesting grain yield might not have been affected by a greater N, P and K fertilizer application. A key to grain yield increase with a more frequent irrigation (shorter irrigation interval) might be using a limiting micronutrient, effective in major nutrients transfer to grain from the other plant tissues or a bed shaping method enhancing its uptake.     

IMPACT OF VERMICOMPOST AND NITROGEN-PHOSPHORUS- POTASSIUM APPLICATION ON BIOMASS PARTITIONING,NUTRIENT UPTAKE AND PRODUCTIVITY OF ARECANUT

A long-term field experiment (1998 to 2010) investigated the effects of vermicompost (VC) and chemical fertilizers (CF) application alone or in combination on biomass partitioning, nutrient uptake and productivity of arecanut. Trunk biomass (kg palm^?1) was significantly higher with integrated treatments (40.8–43.0) than control (23.9). Biomass partitioning to kernel varied between 4.6% in control to 7.7% in CF 100 and 200% nitrogen (N)- phosphorus (P)- potassium (K). The leaf P and K content varied significantly among treatments. The N immobilized in trunk (g palm^?1) was significantly higher in integrated treatments (119-127) than in control (93). Phosphorus and K uptake by trunk followed same trend. The leaf K uptake and total K removed were found significant. The nutrition treatments registered significantly higher kernel yield (2508–3176 kg ha^?1) than control (1721 kg ha^?1). The increased yield of arecanut from chemical fertilizers (73–85%) was more pronounced when compared to VC (48–59%) and integrated treatments (46–63%) over control.     

INFLUENCE OF ALUMINUM ON MINERAL NUTRIENT UPTAKE AND ACCUMULATION IN URTICA PILULIFERA L.

Pollutants can have detrimental effects on living organisms. They can cause toxicity, damaging cells, tissues and organs because of their high concentrations or activities. Plants provide a useful system for screening and monitoring environmental pollutants. Among pollutants, aluminum is considered as a primary growth limiting factor for plants resulting in decreased plant growth and development. Although considered to be a non-essential and highly toxic metal ion for growth and development, aluminum (Al) is easily absorbed by plants. Urticaceae family members have high nutrient requirements demonstrated by leaves containing high levels of calcium (Ca), iron (Fe), magnesium (Mg), and nitrogen (N). Urtica pilulifera is one of the important traditional medicinal plants in Turkey. In this study, U. pilulifera was used as a bioindicator to investigate the possible differences in the absorption and accumulation of mineral nutrients at different levels of the Al exposure and examine the mineral nutrition composition of U. pilulifera under Al stress. Also, some growth parameters (leaf-stem fresh and dry weights, root dry weights, stem lengths and leaf surface area) were investigated. U. pilulifera seedlings were grown for two months in growth-room conditions and watered with spiked Hoagland solution, which contained 0, 100, and 200 μM aluminium chloride (AlCl₃). It was observed that macro- and micro-nutritional status of roots and leaves was altered by Al exposure. The concentrations of some macro- and micronutrients were reduced while concentrations of others were increased by excess of Al. Some macro- and micronutrients were increased at low level of Al whereas reductions were observed at high level of Al, and vice versa. The patterns were dependent on the macro- or micronutrient and the plant part.     

菌根真菌对茶树吸收磷、钾素的影响

以辐照灭菌的酸性黄壤为供试土，种植有性繁殖的茶苗并接种ＶＡ菌根真菌，以不接种菌根真菌为对照，分别追施３２Ｐ－过磷酸钙和＾８６Ｒｂ－氯化铷，试验结果表明：菌根侵染率，＾３２Ｐ组合合为５２．６０％，＾８６Ｒｂ组合为５６．７０％，茶树株高分别对照的２．１０倍和２．５０倍，对磷、钾元素的吸收量分别比对照增加４．６０和３．１０倍，磷肥利用率提高１４．１０％，钾肥利用率提高１７．１３％。     

DYNAMICS OF FABA BEAN GROWTH AND NUTRIENT UPTAKE AND THEIR CORRELATION WITH GRAIN YIELD

Growth parameters and nutrient uptake of faba bean with 12 different genotypes were studied at the end of four subsequent growth periods, viz. first vegetative (V1), second vegetative (V2), first reproductive (R1) and second reproductive (R2) periods for two years and correlated with final grain yield. All parameters including plant height, leaf number, leaf area index (LAI), above ground plant dry matter (DM) and root DM, nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), and magnesium (Mg) uptake and concentration of N, P, K, Ca, and Mg showed different patterns with advancement of the growth period. All the mentioned parameters were fitted in either quadratic or linear equations. Significant correlations were found among nutrients, growth parameters and grain yield during different growth stages. On the basis of these experiments it was clear that nutrient uptake was directly related to biomass. In V2 and R1 biomass production was greatest resulting in high nutrient uptake. Among the growth parameters, biomass and LAI showed the highest significant correlation with grain yield. The findings especially models derived from two year data across twelve genotypes can be used for better fertilizer management of faba bean.     

不同肥料组合对莴笋产量和品质的影响

采用田间小区试验研究了不同肥料组合对莴笋产量、品质和叶片养分形态的影响。结果表明,在施入等量氮肥的基础上,磷、钾、中量及微量元素和有机肥料平衡施用使莴笋极显著增产(135·8%~177·0%),其增产序列依次为NP1K2MgZnB>NP2K2>NP1K2RM>NP1K2PP>NP1K2Mg>NP1K2>NP2K1。不同肥料组合可降低莴笋叶片硝酸盐含量,以NP1K2MgZnB处理降低量最大,降低最少者为NP2K2处理;茎中硝酸盐含量以NP1K2RM处理降低量最大,NP2K1处理降低最小。肥料组合各处理对莴笋营养品质Vc和氨基酸以提高作用为主,以NP1K2MgZnB处理对莴笋产量和品质的效应最好。莴笋叶片养分形态中,氮素以蛋白氮为主,磷素和钾素分别以非蛋白磷和非蛋白钾为主。不同肥料组合对莴笋叶片氮和磷素形态的效应不一致,对3种钾形态均有提高作用。各养分形态中,氮素仅非蛋白氮与茎硝酸盐呈显著负相关,与茎Vc呈显著正相关,与叶氨基酸呈极显著正相关;磷素以非蛋白磷与叶Vc、茎氨基酸呈显著负相关;钾素的非蛋白钾和全钾与叶硝酸盐呈显著负相关,与茎硝酸盐为极显著负相关,与叶Vc、茎Vc呈显著正相关,与茎氨基酸呈极著正相关,蛋白钾与茎硝酸盐呈极显著负相关,与叶Vc、茎Vc、茎氨基酸呈显著正相关,与叶氨基酸呈极著正相关。     

DAIRY MANURE AND NITROGEN FERTILIZER EFFECTS ON RESIDUAL NITRATE AND PHOSPHATE,AND WHEAT YIELD IN A SANDY CLAY LOAM SOIL

Dairy manure (DM) rates of [0 (DM₀), 30 (DM₃₀₎), 60 (DM₆₀) Mg ha^?1] and three nitrogen (N) rates [0 (N₀), 125 (N₁₂₅), 250 (N₂₅₀) kg ha^?1] were tested in a sandy clay loam, to evaluate their effects on growth and yield of wheat crop (Triticum aestivum L.), residual nitrate nitrogen (NO₃-N) and phosphorus (P) concentrations in the surface soil, and selected soil physical measurements [saturated hydraulic conductivity (Ksat), and bulk density (BD)]. Increasing N and DM rates gave higher wheat yields, increased concentrations of residual NO₃-N and P in the surface soil and improved Ksat and BD. Highest grain yield of 3.8 Mg ha^?1 (70.3% more than the control) was observed in DM₆₀ × N₂₅₀ treatment. Residual accumulation of N-NO₃ and P in the surface soil at high N and/or DM application rates suggests the need to carefully manage N and DM inputs on farm fields to avoid environmental contamination.     

NUTRIENT UPTAKE,PHYSIOLOGICAL RESPONSES,AND YIELD ATTRIBUTES OF WHEAT (TRITICUM AESTIVUM L.) EXPOSED TO EARLY AND LATE DROUGHT STRESS

The response of different wheat cultivars to drought imposed after three and six weeks of seedling emergence was evaluated in the wire house. The seeds of recommended local wheat cultivars were sown in plastic pots. The drought stress decreased the water relation, nutrient uptake and grain yield of all the wheat cultivars. The early drought stress significantly reduced the nitrogen (N) uptake by 38% while late drought stress decreased nitrogen uptake by 46%. The phosphorus (P) and potassium (K) uptake were decreased by 49% and 37% under early drought stress, respectively while their uptake was decreased by 51% each under late drought stress. Grain yield was reduced by 24% under early drought stress while it was reduced by 60% under late drought stress. Water deficit at early growth stages reduced grain weight by 10% while it was reduced by 35% under water deficit at later stages of growth.     

NUTRIENT UPTAKE AND USE EFFICIENCY BY TROPICAL LEGUME COVER CROPS AT VARYING PH OF AN OXISOL

Oxisols comprise large soil group in tropical America. These soils are acidic and have low fertility. Use of tropical legume cover crops in cropping systems is an important strategy to improve fertility of these soils for sustainable crop production. Data are limited on nutrient uptake and use efficiency of tropical cover crops under different acidity levels. The objective of our study was to evaluate growth and nutrient uptake parameters of sixteen tropical legume cover crops under three soil pH (5.1, 6.5, and 7.0) of an Oxisol. Shoot dry weight was influenced significantly by pH and cover crop treatments and their interactions, indicating that cover crops used had differential responses to changing soil pH levels. Overall, shoot dry weight decreased when soil pH was raised from 5.1 to 7.0, indicating acidity tolerance of cover crops. Nutrient concentration (content per unit of dry weight), uptake (concentration X dry weight), and nutrient use efficiency (dry weight of shoot per unit of nutrient uptake) varied significantly among cover crops. The variation in nutrient uptake and use efficiency among cover crop species was associated with variation in shoot dry matter production. Significant variation among crop species in dry matter production and low C/N ratios (average value of 14.25) suggest that cover crops which produced higher dry matter yield like white jack bean, gray mucuna bean, black mucuna bean, mucuna bean ana, and lablab are important choices for planting in tropical soils to recover large amount of macro and micronutrients, and to prevent such nutrient leaching in soil plant systems.     

施肥深度对旱地小麦氮素利用及产量的影响

本文用土柱栽培法研究了施肥深度对旱地小麦氮素利用及产量的影响 ,结果表明 :较深层次 (2 0～ 40cm)施肥 ,植株将吸收的氮素较多分配至籽粒 ,分配至根系少 ,肥料氮利用率高 ,土壤残留率和损失率少 ,回收率高 ,从而提高了产量 ;施肥过浅 (0～2 0cm)和施肥过深 (6 0～ 80cm)则相反 ,由此可以认为旱地小麦最佳施肥深度应在 2 0～ 40cm左右 ,可据此制定施肥管理方案 ,以获得高产高效。     

圆褐固氮菌对春小麦产量和氮肥利用效率的影响

利用盆栽和田间试验,探讨了圆褐固氮菌Azotobacter chroococcum beijerinckN45及用其研制的生物氮肥对春小麦产量和氮肥利用效率的影响,旨在为生物氮肥的研制及其与化学氮肥的最佳配比用量提供理论依据。结果表明,盆栽试验中供试菌株N45具有对春小麦的增产作用和对氮肥利用效率的促进作用。将其研制为生物氮肥后,其效果在田间得到了很好的再现,盆栽与田间试验均是与半量化学氮肥配施效果最佳,相比同量化肥处理分别提高春小麦秸秆产量12.70%和16.34%;籽粒产量15.31%和11.77%;氮素收获指数0.68%和0.13%;氮肥农学利用率30.37%和59.39%;氮素吸收利用率26.53%和88.66%;氮肥偏生产力15.27%和11.77%;氮肥生理利用率12.24%和35.24%,同时还能够提高秸秆和籽粒中全氮、全磷和全钾的累积量。     

施氮水平对甘蔗氮素吸收与利用的影响

以新台糖22号(ROC22)为试材,设15N标记尿素2.5、5.0和7.5g/盆(相当于225、450和675kg/hm2)3个处理,采用网室盆栽试验方式,研究施氮水平对甘蔗氮素吸收与利用的影响。结果表明:甘蔗吸收的氮素17.27%～27.28%来自施用的氮肥,72.72%～82.73%来自土壤和种茎;甘蔗氮肥利用率为34.21%～42.46%。随施氮水平提高,甘蔗干物质积累、氮素积累及来源于肥料氮素的比率显著增加,同时蔗叶对氮素的吸收利用呈上升趋势,但蔗茎对氮素的吸收利用呈下降趋势,氮肥利用率也显著下降。土壤碱解氮和硝态氮在各土层中的含量随施氮水平的提高而增加,且两者在0～20cm土层的积累明显大于20～40cm土层。本试验条件下,甘蔗氮肥施用为尿素5.0g/盆(相当于450kg/hm2)及土层深度为20cm较为适宜。     

钾素营养对水稻根系生长和养分吸收的影响

本文研究了大田和盆栽试验中钾素营养对水稻根系形态、活力及其对养分吸收的影响。试验结果表明：（１）在氮磷肥的基础上施钾能促进稻根的生长；（２）土壤供钾潜力、钾肥种类和水稻品种的吸Ｋ特性均影响根系的生长；（３）在缺钾的酸性土壤上，吸钾强的品种，施钾的促根效应最为明显；（４）施钾能增加小于０．２ｍｍ的细根量，提高稻根的再生能力，影响Ｎ、Ｐ、Ｋ、Ｃａ、Ｍｇ等营养元素的吸收及其在地上和地下部分间的分配；（５     

硫对烤烟中镁吸收与积累的影响

通过液培试验研究了不同浓度硫（0.01、2、4、8、16和32mmol/L）处理对烤烟根、茎、叶及全株镁吸收及积累的影响。结果表明,2mmol/L处理显著提高了烤烟根系镁含量（0.6005%）,促进了镁的吸收与积累量,4～32mmol/L处理的镁含量、积累量及吸收速率随硫浓度增加而降低,且显著低于0.01mmol/L处...     

施氮模式对春玉米养分累积特性的影响

通过田间试验,研究了施氮模式对春玉米养分累积特性的影响.结果表明,施氮明显提高了春玉米干物质和NPK的累积量及累积速度,这种影响均在拔节期以后更明显.随着生育期推进,春玉米干物质及NPK的累积量均增加,但增加幅度不同.干物质及NP累积量的增加幅度在大喇叭口期以前较小,大喇叭口期以后较大;K累积量的增加幅度则正好相反,大...