首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 296 毫秒
1.
With the demand for maize increasing, production has spread into more water limited regions. Couple this with increasing resource costs and environmental concerns and the need for efficient nutrient and water management practices has increased. The objective of this trial was to evaluate the effects of different nitrogen (N) fertilizer application methods and timings on maize grain yield, N use efficiency (NUE), and water use efficiency (WUE) under irrigated and rain-fed conditions. Four site-years of data were collected. Fertilizer treatments consisted of all N applied preplant, split surface applied, and split foliarly applied. Irrigation applied prior to and during reproductive growth increased grain yield, NUE, and WUE compared to rain-fed treatments for all site-years. Split surface applied N fertilizer applications typically increased NUE, but not always grain yield compared to preplant applications. The use of split foliar N fertilizer applications was only beneficial in the site-years when leaf burn was not as severe.  相似文献   

2.
ABSTRACT

This study was conducted to formulate an in-season nitrogen (N) fertilization optimization algorithm (NFOA) to estimate midseason N rates that maximize corn (Zea mays L.) growth and minimize fertilizer inputs. Treatments included: a zero kg N ha?1; three treatments of 134 kg N ha?1 fixed rate applied in split, preplant, or sidedress; two treatments of 67 kg N ha?1 fixed rate preplant or sidedress applied; three NFOA-based midseason N rates (RI-NFOA, RICV-NFOA, flat-RICV-NFOA) with (67 kg N ha?1) and without preplant N; and two resolutions (0.34 and 2.32 m2) tested for RICV-NFOA only. With the 67 kg N ha?1 preplant application, midseason RI-NFOA-based N rates resulted in an N use efficiency (NUE) of 65% while the 134 kg N ha?1 fixed rate split applied had 56% NUE. Using the RICV-NFOA, NUE and net returns to N fertilizer were higher when spatial variability was treated at 2.32 m2 resolution.  相似文献   

3.
Abstract

Nitrogen efficiency may be improved in grain sorghum [Sorghum bicolor (L.) Moench.] production by using the optimum N rate, splitting the N applications, and by the use of nitrification inhibitors. Nitrogen rates of 0, 56, 112, 168, and 224 kg N/ha with and without nitrification inhibitors, dicyandiamide (DCD) and nitrapyrin, were evaluated in 1985 and 1986 at two locations in Arkansas. Selected N rates were evaluated when applied all preplant and when the applications were split. In 1986, at one location, two N rates (0 and 168 kg N/ha), DCD and nitrapyrin, and different times of N application were evaluated. These treatments were evaluated at two soil water deficits, 2 and 4 cm. The soils were a poorly drained Sharkey sc (Vertic Haplaquept) in northern Arkansas and moderately well drained Hebert sl (Aeric Ochraqualf) in southern Arkansas. Maximum grain sorghum yield occurred at a lower N rate on the silt loam soil than on the clayey soil in both years of the study. Based on soil inorganic N, the DCD nitrification inhibitor tended to inhibit nitrification during the early growing season on the Sharkey sc. However, the inhibitors did not affect the soil inorganic N on the Hebert sl. Grain yield and plant N were not increased by the inhibitors in any of the studies. Grain yield was not increased by the split N application treatment compared to the preplant N application. However, split N applications increased plant N above the preplant application under high soil moisture conditions.  相似文献   

4.
《Journal of plant nutrition》2013,36(7):1183-1197
Abstract

Nitrogen (N) fertilization continues to be of primary importance in the economically successful production of cotton (Gossypium hirsutum L.). Profit margins of producers might be expanded by increasing the uptake efficiency of applied N. Recently, N fertilization of crops grown in the Mississippi River Delta has been suspected to impact water quality in the Gulf of Mexico. Improving efficiency of N uptake could alleviate some environmental concerns by increasing the retention of N at the site of application. The objective of this study was to determine the impact of replacing preplant N applications with postemergent N applications on the growth and yield characteristics of cotton. Delayed applications of the recommended rate of N fertilizer (112 kg N ha?1) were tested for four years under irrigated and dry land production conditions. The N rate was applied either preplant, after crop emergence, or at first square. Further, 112 kg N ha?1 was split applied evenly at preplant + first square, and after emergence + first square. The five 112 kg ha?1 N treatments were compared to an unfertilized control. Yield tended to be maximized with N treatments that included a first square application. Yields were usually lowest in the unfertilized control and the 112 kg N ha?1 preplant treatments. Not surprisingly, both yield and plant growth was influenced more by irrigation than N fertilization. Years when drought conditions caused water stress and limited plant growth, dry land cotton had only limited response to the N fertilization treatments. Irrigated cotton responded to N treatments all years with increased growth and yield. Optimizing agronomic considerations, the best N fertilization timing was an after emergence + first square split application.

  相似文献   

5.
《Journal of plant nutrition》2013,36(7):1345-1353
Abstract

A three‐year field study was conducted to evaluate cotton (Gossypium hirsutum L.) response to the source and timing of nitrogen (N) on an irrigated coastal plain soil (Lucy loamy sand; Arenic Kandiudults) in south Alabama. Cotton acreage in this region has increased in the past ten years and there was a need for current data describing cotton response to N fertilization. Treatments included N sources, timing of N application (ammonium nitrate), split applications of N (ammonium nitrate and ammonium sulfate), and a no‐N check. Nitrogen sources applied preplant included: (i) ammonium nitrate (34‐0‐0); (ii) ammonium sulfate (21‐0‐0‐24.2); (iii) urea (46‐0‐0); (iv) urea–ammonium nitrate solution (UAN; 32‐0‐0); (v) UAN + ammonium thiosulfate (28‐0‐0‐5). Non‐sulfur sources were applied with and without additional sulfur (S). Times of application were preplant, first true leaf, first square, and first bloom. Two treatments received split applications of N as a 50:50 mixture of ammonium sulfate with urea or ammonium nitrate. Supplemental applications of potassium (K) were evaluated by applying ammonium sulfate in combination with 56 kg K/ha. Yield data showed some minor differences among sources, but overall the results of this three‐year study show that there were no superior N sources. For ammonium nitrate, preplant applications of N were sufficient in two out of three years. Split applications of ammonium nitrate did not improve yields as compared to preplant N. Applying ammonium sulfate with supplemental K or as a 50:50 mixture with ammonium nitrate or urea did not improve yields as compared to ammonium sulfate or ammonium nitrate applied alone. Lint quality was not affected by N fertility treatments.  相似文献   

6.
Abstract

Influence of two rootstocks and five levels of hand thinning (fruit spacing) on yield, fruit quality at harvest and after storage, and leaf and fruit elemental composition of ‘Redspur Delicious’ apple (Malus domestica Borkh.) were studied. Trees on M.7 rootstock had a higher yield with heavier and firmer fruit at harvest than those on M.26. Trees on M.7 had significantly lower leaf and fruit N which resulted in a darker fruit color than those on M.26 rootstock. Fruit from trees on M.26 had a higher soluble solids concentration (SSC) at harvest than those on M.7. Leaf and fruit potassium (K) increased but fruit calcium (Ca) decreased with an increase in fruit spacing. Thinning fruit to 10 cm or 18 cm spacing, depending on market demand for fruit size, is recommended for improvement of fruit quality. Fruit weight and quality was improved with 18 cm fruit spacing without a significant decrease in yield, while thinning fruit further than 18 cm apart reduced yield without a significant change in the fruit weight or quality.  相似文献   

7.
An established two‐year‐old stand of ‘Apollo’ alfalfa (Medicago saliva L.) was used to determine the alfalfa yield and macronutrient contents response to potassium (K), sulfur (S), boron (B), and molybdenum (Mo) fertilization under a high yield environment. A split, split block field design was used with nine micronutrient treatments (0, 50, and 100 g Mo ha‐1 and 0, 1, and 2 kg B ha‐1) in a factorial arrangement (32) as the subplots and three K levels (150, 300, and 600 kg K ha‐1) as the main plot in three replications. Two levels of S (0 and 240 kg S ha‐1) fertilization were applied in strips across the main plots (K levels) resulting in the split, split block design. Alfalfa yield and macronutrient contests were determined. Increased in K or S rate increased K contents of the plants, however, the differences between the K or S rates were not significant and B or Mo application did not have a marked effect on alfalfa K levels. Alfalfa calcium (Ca), magnesium (Mg), or phosphorus (P) content was not significantly affected by K, S, B, or Mo fertilization. Potassium, S, B, or Mo fertilizer application also did not have a marked effect on alfalfa yield during this study. Combinations of K, S, B, and Mo fertilizer had variable effects and the effects were dependent on the combination of fertilizer, sources, and levels. With a few exceptions, there was lack of alfalfa yield and nutrient contents response to K, S, B, and Mo applications which was due to the effect of low available soil moisture as a result of low incident rainfall during the study on these nutrients availability, uptake, and alfalfa growth.  相似文献   

8.
Abstract

Grain deficits frequently occur in the Southeastern Atlantic Coastal Plain because erratic rainfall patterns and soil properties often limit corn (Zea mays L.) yields, however, harvesting corn for silage may enable farmers to produce a second grain crop during the same calendar year. Effects of row spacing, plant population, and fertilizer program on yield, quality, and mineral concentrations of corn silage grown with irrigation on Typic Paleudult soils were therefore investigated. Two plant population treatments which averaged 7.0 and 10.1 plants m‐2 were evaluated with two fertilizer programs that differed in N, N and K, and N, P, and K in 1980, 1981, and 1982, respectively. Each plant density by fertilizer combination was evaluated in single rows spaced 96 cm apart and in twin rows which approximately doubled the intrarow plant spacing. Plot size for the 2×2×2 factorial experiment ranged from 30 to 44 m2. Yield, quality, and mineral concentrations of corn silage grown in single rows spaced 96 or 75 cm apart and twin rows were also evaluated in large (185 m2) plots under center pivot irrigation during 1981 and 1982.

Dry matter yields of 22 to 26 Mg ha‐1 were achieved with plant densities of 6.7 to 13.5 plants m‐2 at both experimental sites. Highest silage yields were produced with stand densities of 9 m or more planted in single 75 cm or twin rows, but yield differences were statistically significant at P(0.05) in only two of five site years. Increasing total N‐P‐K application beyond 200–30–167 kg ha”; increased crude protein slightly in 1980 and significantly in 1981 and 1982. Concentrations of Mn and Zn in silage were increased by higher fertilization, presumably because nitrification reduced surface soil pH and increased their availability. Dry matter yield, fiber, energy, and other mineral nutrients were not significantly influenced by fertilizer program. These experiments identified management practices for the Atlantic Coastal Plain which resulted in corn silage yields equal to those produced in the cooler mountain region of Georgia and that exceeded current average production in South Carolina by approximately 40% without reducing apparent feed quality.  相似文献   

9.
In 1991 and 1992, drip irrigation was used to apply various rates and timings of nitrogen (N) and potassium (K) to black polyethylene plastic‐mulched bell pepper (Capsicum annuum L.) to determine the effect on fruit quality and susceptibility to postharvest bacterial soft rot (Ervinia carotovora subsp. carotovora). Neither rate nor application timing affected total yield in either year. In 1991, the high fertilizer rate (266–309 kg/ha of N and K, respectively) increased class 1 yield in the first harvest and reduced total discards. In 1992, a year with a colder than average spring, the low fertilizer rate (70–81 kg/ha of NK) increased class 1 yield in the first harvest. Mid‐ or late‐season fertigation produced more second harvest yield and less discards than the first harvest in 1991, but not in 1992. Fruits of plants fertilized with high N and K rates had greater N and dry matter concentration. No differences in color or wall thickness at harvest were detected among treatments. Stored fruits turned red slower with the late season low fertilizer rate. There were no differences in rate of weight loss during storage at 10°C. No differences in progression of bacterial soft rot were detected among treatments in 1991, but the higher fertigation rates or late timing application increased resistance in 1992.  相似文献   

10.
Maize grain yield potential can be estimated mid-season using NDVI at the V8 growth stage, thus affording delayed sidedress nitrogen (N) application. Several combinations of preplant and sidedress N at various growth stages were evaluated. Maize grain yields were maximized with 90 kg N ha-1 preplant followed by 90 kg N ha-1 sidedress at V6 or V10 (8 of 9 site-years). Delaying N application until V10 growth stage when preplant N was applied did not result in lower yields. Mid-season N supplies fertilizer at the time when crop need and N uptake are at a maximum, and thus facilitates more efficient N use. Lowest nitrogen use efficiencies (NUE) were observed with higher N rates and when all N was applied preplant. Highest NUE's were achieved with 45 kg N ha-1 preplant followed by 45 kg N ha-1 sidedress applied at V6 growth stage (8 of 9 site-years) and at V10 (6 of 9 site-years).  相似文献   

11.
This study was conducted to investigate the effects of salinity stress and flower number on growth, yield, water use efficiency (WUE), and fruit quality of cherry tomatoes cultivated under soilless conditions. The experiment was conducted in a plastic house (5-m wide × 11-m long) located in Gifu University. The seedlings were transplanted in a randomized complete block design with six plants per treatment (NT1 and ST1 were with four plants), giving a total of 44 plants in 22 pots (two plants per pot). Two different salinity levels [no-salinity and salinity with electrical conductivity: 0.8 and 3.0 dS m?1, respectively] and four flower number treatments (8, 13, 18, and free per truss) were investigated in the experiment. The results showed that salinity stress negatively affected tomato growth, yield, and marketable yield, but improved tomato fruit quality. The number of flowers had no effect on tomato growth variables and WUE, but the yield significantly increased with increasing flower number. However, the fruit quality was decreased with increased flower number. A reasonable control for fruit load can increase marketable yield in commercial cultivation. Under salinity stress conditions, properly increasing the number of flowers can avoid yield reduction.  相似文献   

12.
不同氮肥水平对日光温室黄瓜品质和产量的影响   总被引：14，自引：0，他引：14  
为合理施肥，实现设施栽培蔬菜的优质高产，该文就5种氮肥水平（不施肥、只施基肥膨化于鸡粪22．5t／hm^2、基肥＋追肥N540、1080、2160kg／hm^2）对日光温室黄瓜品质和产量的影响进行了研究。结果表明：随施肥量的增加黄瓜果实的维生素C、可溶性蛋白、游离氨基酸、可溶性糖和有机酸含量均有增加的趋势，风味也有改善，味甜、香气浓，但黄瓜硝酸盐含量呈直线上升。施肥过量还会导致黄瓜脆度下降，商品瓜率和总产量显著降低。综合考虑产量和品质两个因素，在中等使用年限，中等土壤肥力的日光温室黄瓜冬春茬栽培中，每公顷施用于鸡粪22．5t作为基肥，配施化学肥料N540kg做为追肥，能获得较高的产量和较好的品质；过少或过量的施肥均不利于黄瓜产量和品质的形成。  相似文献   

13.
During the cultivation period of 2005–2007, a project was carried out in the region of Eirinoupolis, prefecture of Imathia, Macedonia, northern Greece. The study investigated the application of boron (B) timing (flowering, fruit set, fruit growth) and method (soil and foliage) on the vegetative growth, fruit yield and quality, and nutritional status of the cling-stone peach variety Andross. The cultivar was grafted onto an 8-year-old rootstock GF 677. The results showed that the greatest marketable yield (135 kg tree–1) was achieved in peach trees where B was applied on soil during the flowering stage in combination with a balanced nitrogen–phosphorus–potassium (NPK) basal application. Boron concentration in fruits of that treatment was increased in both cultivation years compared to most of the applied treatments. Foliar application of B at flowering, fruit set, and fruit growth, primarily in combination with foliar calcium (Ca) application, showed fruits to be less affected by cracking and Monilinia over all treatments. However, foliar application of Ca did not significantly promote leaf or fruit Ca concentration.  相似文献   

14.
A field experiment was conducted in Southern Italy to evaluate the effects of different water quality and fertilizers on yield performance of tomato crop. In mineral nitrogen (N) fertilizer and irrigation with fresh water (Electrical Conductivity, EC, = 0.9 dS m?1) (FWF); mineral N fertilizer and irrigation with saline water (EC = 6.0 dS m?1) (SWF); municipal solid waste (MSW) compost and irrigation with fresh water (EC = 0.9 dS m?1) (FWC); MSW compost and irrigation with saline water (EC = 6.0 dS m?1) (SWC). At harvest, weight and number of fruits and refractometric index (°Brix) were measured, total and marketable yield and dry matter of fruit were calculated. The results indicated that MSW compost, applied as amendment, could substitute the mineral fertilizer. In fact, in the treatments based on compost application, the tomato average marketable yield increased by 9% compared with treatments with mineral fertilizer. The marketable yield in the SWF and SWC treatments (with an average soil EC in two years to about 3.5 dS m?1) decreased respectively of 20 and 10%, in respect to fresh water treatments. At the end of the experiment, application of compost significantly decreased the sodium absorption rate (SAR) of SWC treatment in respect of SWF (?29.9%). Significant differences were observed among the four treatments both on soil solution cations either exchangeable cations. In particular compost application increased the calcium (Ca) and potassium (K) contents in saturated soil paste respect to the SWF ones (31.4% and 59.5%, respectively). At the same time saturated soil paste sodium (Na) in SWC treatment recorded a decrease of 17.4% compared to SWF.  相似文献   

15.
A field experiment was conducted to study the effect of planting material and plant density on stevia (Stevia rebaudiana Bertoni) under western Himalayan conditions during 2011 and 2012. The experiment conducted in a split plot design consisted of two types of planting material (rooted slips and fresh seedlings) in the main plot and five inter- and intra-row spacing in subplots with three replications. Yield attributes and dry leaf biomass yield of stevia were not affected by the type of planting material; however, plant density significantly influenced the yield attributes and leaf and stem dry biomass. Although the wider spacing (60 × 45 cm) gave more leaves, higher leaf area index, higher leaf dry mass per plant as compared to closer spacing, it resulted in lower values of these attributes per unit area. Plants spaced in 30 × 30 cm accumulated 41.2% and 42.8% more total biomass than 60 × 45 cm. Steviol glycoside content did not change due to different planting materials and plant densities; however, closer plant spacing (30 × 30 cm) recorded 114.8% and 70.0% higher steviol glycoside accumulation compared to wider row spacing (60 × 45 cm) in 2011 and 2012, respectively.  相似文献   

16.
The point at which nitrogen (N) applied approaches 100% recovery in the soil once plant and microbial sinks have been saturated has not been determined in winter wheat (Triticum aestivum L.) production systems. In dryland winter wheat, subsoil accumulation has not been found to occur until N rates exceed that required for maximum yield. Many conventional N rate experiments have not properly evaluated subsoil N accumulation due to the lack of equally spaced N rates at the high end of the spectrum over which accumulation is expected to occur. Therefore, the objectives of this study were to (i) determine when soil profile accumulation efficiencies reach 100% in continuous winter wheat production and (ii) to evaluate the potential for nitrate‐nitrogen (NO3 ‐N) leaching in continuous winter wheat when extremely high rates of fertilizer N are used. Two field experiments (T505 and T222) were conducted for two years using ten N rates (preplant‐incorporated) ranging from 0 to 5376 kg N ha1. No additional preplant fertilizer was applied in the second year. Following the first and second year wheat harvest, soil cores were taken to 2.4 m and bulk density, ammonium‐nitrogen (NH4‐N) and NO3‐N were determined. Crop N‐use efficiency (NUE) (N uptake treated ‐ N uptake check/rate applied) and soil profile inorganic N accumulation efficiencies (NAE) [net inorganic N accumulation in the soil profile/(fertilizer applied ‐ net N removed in the crop)] changed with fertilizer rate and were inversely related. Priming (increased net mineralization of organic N pools when low rates of fertilizer N are applied) may have occurred since increased NUE was observed at low N rates. The highest N‐accumulation efficiencies were at N rates of 168 and 448 kg ha‐1 in experiments T505 and T222, respectively. At both T222 and T505, no subsoil accumulation of NH4‐N or NO3‐N beyond 100 cm was observed for any of the N treatments when compared to the 0‐N check, even when N rates exceeded 448 kg ha‐1.  相似文献   

17.
A two-year field experiment (2001 and 2003) was carried out in a Mediterranean environment to study the effects of municipal solid waste (MSW) compost application compared with mineral nitrogen (N) fertilization on the agronomic performance and N utilization of a tomato crop, in rotation with durum wheat. The research was conducted in the south of Italy where five N treatments and two soil tillage depths (40-45 cm and 10-15 cm) were compared. The N treatments were: MSW compost at 140 kg ha?1 (Ncom); mineral N fertilizer at 140 kg ha?1 (Nmin); MSW compost combined with mineral N fertilizer (Nmix) (70 kg ha?1 as organic N plus 70 kg ha?1 as mineral N); mineral N fertilizer at 70 kg ha?1 combined with two applications of foliar fertilizer (Nfito) (3 kg ha?1 as hydrolyzed proteins), and an untreated control (Contr). During cropping cycles, growth parameters and plant N status (SPAD readings and petiole nitrate content) were determined; at harvest the marketable, overripe, green fruit, total yield, yield components, quality performance, total and fruit N uptake, and N efficiency were recorded. In addition, at the beginning and at the end of the two-year experiment, soil chemical characteristics and mineral N was measured, allowing for the calculation of the mineral N deficit in the soil. The results of this research indicate that the application of MSW compost to tomato plants can serve as a N source in Mediterranean conditions, especially when MSW compost is combined with mineral N fertilizer and deeper soil tillage is applied. In fact, deeper soil tillage increased total yield 7.0 t ha?1 compared to surface tillage, whereas soil amended with MSW compost increased total yield compared to the untreated control by approximately 6.4% when used alone and 11.1% when combined with mineral N fertilizer. Nitrogen utilization parameters and Harvest Index varied significantly across years and N treatments. Petiole nitrate content and SPAD readings did not vary between Nmin and Nmix treatments, but they were significantly different from the untreated control. This indicates that plant N status was an effective tool to monitor N supply. After the two-year experiment, the Nmix treatment was statistically not significant in total yield (86.1 and 88.2 t ha?1, respectively), marketable yield (66.9 and 67.7 t ha?1) and quality compared to the Nmin treatment. Furthermore, the Nmix treatment ensured the least N deficit in the soil, indicating that MSW applications were effectively used as alternative organic supplements. Finally, the results indicated a positive effect of MSW application on organic carbon content in the soil and did not show any significant increase of the heavy metals at the end of the two-year experiment.  相似文献   

18.
Abstract

Field experiments were carried out on three representative soils, to evaluate the effect of various starter fertilizers, together with different rates of band placed phosphorus (P), on nutrient uptake and yield of spring barley (Hordeum vulgare L.) and spring wheat (Triticum aestivum L.). The starter fertilizers were placed in the immediate vicinity of the seed, while the band placed P was placed at about 5 cm below the seeds and spaced at 25 cm between alternate seed rows. As starter fertilizer, monoammonium phosphate (MAP), calcium nitrate (CAN), ammonium nitrate (AN) and triple superphosphate (P20) were compared. In both species, effects of starter fertilizer on P uptake were most marked early in the growing season. At GS 13 application of 20 kg P ha?1 as MAP increased the P uptake by 50% in barley and by 35% in wheat, compared to no seed-placed nutrients. For grain, the increase in P content was 8% for both species. The higher P uptake at GS 13 was supported by observations of higher plant vigour in the treatments with either P20 or MAP as starter fertilizer. The use of N only as starter fertilizer did not increase the vigour of the plants. Band placement of P also gave more vigorous plants in spring barley. The grain yield increased on the silty clay loam and on the silt soil when starter fertilizer was applied, especially with the use of MAP. Smaller and non-significant yield differences were found when starter fertilizer was used on the loam soil. No delay or reduction of emergence was observed with starter fertilizer. Therefore, on soils where root growth or nutrient uptake becomes limited during the first weeks after sowing, application of starter fertilizer is recommended in Norway for both spring barley and spring wheat. Crops grown on silty soils seem to have an especially high demand for easily available P given as starter fertilizer.  相似文献   

19.
A three-year field experiment was carried out in Mediterranean conditions to study the effects of different irrigations and organic fertilizers on yield, quality and nitrogen utilization of eggplant crop and on soil properties. In a split-plot design, two irrigation treatments (re-establishing 100% and 50% of the calculated maximum evapotranspiration) and four fertilizer treatments (mineral fertilizer, commercial stable manure, anaerobic digestate and municipal solid waste compost) were compared. The highest water volume increased significantly the total and marketable yield, the number of marketable fruits, the dry matter of fruits and the nitrogen-use efficiency with respect to the treatment with the lowest irrigation. Nevertheless, the same treatment decreased significantly the fruit dry matter percentage and total soluble solid content. The lowest water volume led to an improvement of fruit quality. Anaerobic digestate increased significantly the total and marketable yield and dry matter compared with compost. Harvest index, nitrogen harvest index, pH, acidity and total soluble solids did not show significant differences among all fertilizer treatments. N translocation ability of plants and fruit quality were not influenced by the type of fertilizer. At the end of experiment, anaerobic digestate and compost reached the highest levels of soil total organic carbon and humic and fulvic acids content. Besides, anaerobic digestate increased the total extractable carbon, phosphorus and nitrogen content compared to all other treatments. Soil copper, nickel and lead content in all treatments enhanced compared to that at the beginning of experiment, but this accumulation did not represent a possible environmental risk. The content of heavy metals in the soil, after 3 years of application, did not exceed the limits imposed by the Italian law. This study showed that the organic wastes, after being adequately processed, could be applied successfully in agriculture especially in arid environments, characterized by quick mineralization and very low organic matter content.  相似文献   

20.
Concern over the pollution potential of nitrogen (N) fertilisers has prompted studies of the utilisation efficiency of applied N by crops. This study was conducted to determine the efficiency of N usage by bell pepper (Capsicum annuum L.) grown with plastic mulch and trickle irrigation, and to define a rate of applied N which is equal to uptake by the crop. The relationships between applied N (0, 70, 140, 210, and 280 kg/ha), nutrient uptake, and yield for spring and autumn bell pepper crops grown on a major soil type (Tropeptic Eutrustox) in the Bundaberg region of subtropical Australia were investigated. Maximum dry weight yield of fruit, leaves, roots, and stems corresponded with N210 to N280 for both spring and autumn crops. In addition, maximum fresh weight of marketable fruit corresponded with N210 to N280 for both seasons. Nitrogen uptake was equal to the applied rate at N140. Plant uptake of elements increased with applied N and, at N280, were ranked as follows: K> N> Ca> Mg > S > P. Fruit accumulated the greatest proportion of K, N, and P (40 to 64%, 40 to 64%, 49 to 76%, respectively), and only a comparatively small amount of Ca (6 to 7%). The efficiency of fruit production from absorbed applied N declined with increasing N rate. District standard rates of P, N, K, and S application exceeded uptake by plants grown at an equivalent N rate (differences of 68 and 65 kg P, 57 and 52 kg N, 32 and 24 kg K, and 19 and 24 kg S for spring and autumn, respectively). Because of the importance of pepper yield as a determinant in economic outcome and the relatively low cost of fertiliser N, application rates in excess of N140 are likely to continue by district growers in an attempt to maximise yield.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号