Rate of nitrogen application during the growing season alters the response of container-grown rhododendron and azalea to foliar application of urea in the Autumn

Summary

One-year-old rhododendron (Rhododendron ‘H-1 P.J.M’) and azalea (Rhododendron ‘Cannon’s Double’) plants grown at different nitrogen (N) fertilisation rates were used to assess the influence of soil N applications during the growing season, and foliar applications of urea in the Autumn, on N uptake and accumulation, and plant growth in the following Spring. N uptake efficiency declined linearly during the first growing season with an increasing rate of N fertilisation. For both cultivars, foliar urea application in the Autumn significantly increased plant N content without affecting plant size, regardless of plant N status. Leaves of rhododendron accumulated more N than other plant structures. Plants sprayed with foliar urea in the Autumn had more new growth the following Spring than plants receiving no urea, regardless of whether the plants received fertiliser in the Spring. For azalea, N uptake in the Spring was, in general, not affected by applications of urea during the previous year. For rhododendron, urea application in the Autumn decreased N uptake the following Spring. For both cultivars, increasing N availability during the growing season increased the ratio of above-ground to below-ground dry weight. Our results suggest that combining optimum N applications during the growing season with foliar application of urea in the Autumn can improve N uptake efficiency, increase N storage, and optimise growth in Rhododendron.     

Bulb and inflorescence development in Leucocoryne ixioides (Hook.) Lind.

Summary

Leucocoryne (Alliaceae) is a genus of bulbous plants with cut-flower potential. They are native to central Chile, which experiences a Mediterranean climate. The plants are ‘dormant’ during the heat of Summer (as bulbs, with no external leaf or root development). Leucocoryne plants ‘resume’ growth in Autumn, with the arrival of the rains and falling temperatures, and flower towards the end of their growth cycle, as temperatures rise again in Spring. Leaf and inflorescence initiation began during the Summer ‘dormant’ period and ended the following Spring. They emerged from the bulbs during the same growth cycle as they initiated. Leucocoryne bulbs consist of a series of sympodial units, each containing two leaves and a terminal inflorescence. The renewal meristem for each unit was initiated at the base of the inflorescence, in the axil of the younger leaf primordium. Leucocoryne bulbs were replaced each growing season. Secondary bulbs were initiated in the axils of the oldest, recently-initiated, leaves during late Spring.     

烯效唑对甜玉米种子萌发及幼苗生理特性的影响

采用不同浓度的(0,10,20,30,40,50,60 mg/L)烯效唑溶液对甜玉米种子浸种处理7 h,幼苗培养,测定相关形态和生理指标.试验结果表明,10～60 mg/L浓度范围的烯效唑浸种可提高甜玉米的发芽势和发芽率;随着烯效唑浓度升高,植株矮化,根长、地上干质量、地下干质量、叶面积以及根冠比均增加.与对照相比,幼苗叶片过氧化物酶(POD)、超氧化物歧化酶(SOD)活性增强,丙二醛(MAD)含量降低,可溶性糖、蛋白质和叶绿素含量升高.试验结果进一步证明了烯效唑能够壮苗,提高保护性酶的活性,增强甜玉米幼苗的抵抗逆境的能力,使用浓度以40～50 mg/L为佳.     

The influence of naphthaleneacetic acid on the growth of in vitro cultivated seedlings of Bromeliaceae

The role of NAA during in vitro seed germination and subsequent growth was examined in three Bromeliaceae: Guzmania minor var. ‘Vella’ Mez, Guzmania lingulata var. ‘Splendens’ Mez and Vriesea splendens var. ‘Fire’ Lem. NAA incorporation in the medium resulted in a strong stimulation of root and shoot growth, with an optimum response at 0.5–0.8 mg l^?1. It is hypothesized that the usual slow growth of bromeliad seedlings in soil is primarily due to poor rooting, which is the result of auxin deficiency.     

Spatial distribution of Malus root systems in irrigated,trellised orchards

Summary

Root distribution was determined for apple trees [Malus sylvestris (L.) Mill. var. domestica (Borkh.) Mansf. ‘Fuji’/’M.26’ (syn. M. domestica Borkh. non Poir.)] 1, 2 and 3 years after planting in trellised orchards in central Texas. Using a soil-coring method, measurable differences were detected in root-length density (RLD; root length per unit volume of soil) by tree age, soil depth, radial distance from the tree, and spatial bearing within and across rows (P ≤ 0.05). For fine roots (root diameters < 1 mm), mean RLD values were 0.1028, 0.1139 and 0.2911 cm cm^–3 for 1, 2 and 3 year-old plantings, respectively. For coarse roots (root diameters 1–5 mm), mean RLD values were 0.0006, 0.0009 and 0.0015 cm cm^–3 for 1, 2 and 3 year-old plantings, respectively. Mean RLD values declined for both fine and coarse roots of all ages with increasing soil depth and radial distance from the trunk (P ≤ 0.05). Similar patterns were observed for the number of soil cores containing measurable roots. The percentage of samples with no roots increased with increasing soil depth and distance from the trunk (P ≤ 0.05). When examining fine roots by spatial bearing from the tree, the greatest RLD was found along the drip irrigation lines for the two youngest plantings and along drip irrigation lines and beneath shaded trellises for the oldest planting (P ≤ 0.05). For coarse roots, the greatest RLD was found along the drip irrigation lines for all plantings (P ≤ 0.05). This information is important for predicting the rates and locations of new root growth in orchards after transplanting, so that management techniques (e.g., fertilisation, irrigation, control of soilborne diseases) can be properly targeted and effectively implemented.     

Morphology,yield and quality of ashwagandha (Withania somnifera L. Dunal) roots and its cultivation economics as influenced by tillage depth and plant population density

Summary

Ashwagandha (Withania somnifera L. Dunal; Solanaceae) is being cultivated around the world mainly for its root which has rejuvenative properties. Field experiments during 1999–2001 under semi-arid tropical conditions of Hyderabad, India studied the effect of tillage depths (15 and 30 cm) and plant population densities (20, 40, 60 and 80 plants m^–2) on root morphology, yield and quality and cultivation economics of ashwagandha. Preparatory tillage to 30 cm depth in combination with a density of 60 plants m^–2 gave the highest root yield of 1.2 t ha^–1 which was 50% higher than that following 15 cm tillage depth and the same density. This is attributed to the favourable effect of the former treatment leading to 33, 37 and 21% increases in plant height, number of branches per plant and shoot biomass yield, respectively. Further, this treatment produced most (68%) best quality root pieces. Main root length, length of lateral roots and diameter of lateral roots were significantly increased, while the diameter of main root and the number of laterals decreased. Furthermore, increase in plant density from 20–80 plants m^–2 increased production of best quality roots from 42% to 59% under shallow tillage and from 53% to 71% of root yield under deep tillage. The implications of change in root morphology are discussed in the light of production of different grades of roots, their market preferences and economics. Deep tillage was equally advantageous for seed production, but plant population density for maximum seed yield (211 kg ha^–1) was lower at 40 than at 60 plants m^–2 for maximum root yield. Maximum gross and net returns and benefit-cost ratio occurred following the highest root yield.     

模拟不同降雨条件对日光温室填闲作物糯玉米产量、根系生长及养分吸收的影响

以“天紫22号”糯玉米为试材,于2009年夏季北京市郊农业园区蔬菜温室休闲期,模拟不同降雨条件,研究其对填闲作物糯玉米产量、根系生长和养分吸收的影响.结果表明:在不同降雨条件下,D-2和F-2处理鲜糯玉米产量分别达到13.4 t/hm2和13.3 t/hm2,产量差异不显著;F-2处理对氮、磷、钾养分吸收量均低于D-2处理,说明大量降水影响作物对养分的吸收;D-2处理各土层的根长密度和根系干重均高于F-2处理,说明适当干旱有助于根系生长和养分的吸收,减少土壤养分的流失.     

烯效唑对甜玉米种子萌发及幼苗生理特性的影响

采用不同浓度的（0,10,20,30,40,50,60mg／L）烯效唑溶液对甜玉米种子浸种处理7h,幼苗培养,测定相关形态和生理指标。试验结果表明,10-60mg／L浓度范围的烯效唑浸种可提高甜玉米的发芽势和发芽率;随着烯效唑浓度升高,植株矮化,根长、地上干质量、／ET干质量、叶面积以及根冠比均增加。与对照相比。幼苗叶片过氧化物酶（POD）、超氧化物歧化酶（SOD）活性增强,丙二醛（MAD）含量降低,可溶性糖、蛋白质和叶绿素含量升高。试验结果进一步证明了烯效唑能够壮苗,提高保护性酶的活性,增强甜玉米幼苗的抵抗逆境的能力,使用浓度以40—50mg／L为佳。     

Yields and the extent and causes of damage in cauliflower,bulb onion,and carrot grown under organic or conventional regimes

Summary

The effects of organic vs. conventional growing practices on yield, pest attacks, N uptake, and NO₃^– contents of three vegetable crops were examined. A range of cultivars of cauliflower (Brassica oleracea L. cv. Botrytis), bulb onion (Allium cepa L.), and carrot (Daucus carota L.) were grown organically and conventionally in a sandy-loam soil. Ranking of cultivars according to yield and susceptibility towards insect attack and fungal disease was similar in the two systems. Yields of cauliflower and onion were 20% and 45% higher, respectively, when grown conventionally. No differences in carrot yields and discard rates were observed between the two systems. Generally, the reasons for discarding varied between the two systems. In organically grown cauliflower, damage by slugs was the main reason for discarding, with 9% discarded, while hollow stem was more prevalent in conventionally grown cauliflowers, where 7% was discarded. No statistically significant differences were found between discard rates or causes in bulb onions grown organically or conventionally. Conventionally grown carrots were significantly more damaged by carrot root fly with 5% of carrots discarded, even though the flies were also present in the organic system. In contrast, more carrots with morphological defects were seen in the organic system, where 29% were discarded. The lower yields in organically grown vegetables can be explained mainly by the management practices specific to the organic system that are designed to facilitate weed and pest management. In addition, inadequate early nutrient supply provides a possible explanation for the lower yields in organically grown cauliflowers and onions, as well as the lower planting density of onions.     

The Effects of Manurial Treatments on The Yield and Quality of Carrot Seed

Seed crops of carrots were grown in 1962, 1963 and 1964, on plots of a 2⁴ N, P, K and farmyard manure factorial experiment. Significant seed yield responses were obtained to each of the fertilizers and to manure, as compared with the yields from the control plot with no manure or fertilizers.

Except when a seed-borne disease caused by Stemphylium radicinum was present, the germination of the ungraded seed was well above the statutory declarable minimum of 60% and there were no significant differences in germination caused by the manurial treatments.

The seed produced in 1963 and 1964 was of similar mean chemical composition to commercial seed and, although its composition was affected by the nitrogen and farmyard manure dressings, these variations in composition did not affect the yield of roots obtained from field sowings of the 1963 seed. The 1962 seed was exceptional in having a lower mean phosphorus concentration than commercial seed. The seed with the lowest phosphorus concentration was obtained from the plots which had received nitrogen but not phosphorus fertilizers, and the root yields from such seed were significantly lower than those from the seed containing higher concentrations of phosphorus.     

Cultural Variation and Mycorrhizal Status of Blueberry Plants in NW Oregon Commercial Production Fields

ABSTRACT

Ericoid mycorrhizal fungi (EMF) form symbiotic relationships with roots of blueberry plants providing increased access to nutrients from fertilizers and soil. In August of 2001, we sampled 55 fields in Oregon to assess the mycorrhizal status of blueberry plants under production conditions and to determine whether any relationships exist between field characteristics, root distribution, soil characteristics and level of colonization by mycorrhizal fungi. Variation in measured soil characteristics, root type, root distribution and mycorrhizal colonization occurred with cultivar, field age, bed type, rate of nitrogen fertilization, irrigation type, and mulch. Root biomass was lower in the upper 15 cm of soil compared to 15-30 cm depth. Distribution of roots between the two sampled depths varied significantly with field age, nitrogen fertilization rate, and the time of 50% harvest for the different cultivars sampled. Root length was generally greatest in the upper 15 cm of the soil than at the 15-30 cm depth. Root colonization by ericoid mycorrhizal fungi (EMF) ranged from 0.5 to 44% of total root length with higher colonization generally occurring in the upper 15 cm of the soil where the majority of smaller, finer roots were found. Colonization generally increased with increasing plant age. In young plants the highest levels of colonization were found in roots from the upper 15 cm of soil while in older plants the highest levels of colonization were found in roots at the 15-30 cm depth. Colonization of roots by EMF in the upper 15 cm of the soil tended to decrease with increasing N fertilization rate, while root colonization at the 15-30 cm depth was unaffected by rate of N fertilization. Roots on cultivars that fruited early in the season tended to have higher levels of colonization than cultivars that fruited later in the growing season. Root biomass and root length were negatively correlated with soil pH and available Ca in soil, while root colonization by EMF was negatively correlated with ammonium levels in the soil. Differences in soil characteristics, root type and distribution, and mycorrhizal colonization found in this study need to be investigated in terms of production efficiency of blueberry in Oregon.     

土壤有机碳和全氮含量及其与海拔、植被和气候要素的关系——以祁连山中段北坡为研究对象

调查分析祁连山北坡土壤有机碳和全氮含量随海拔变化的趋势及其与气候要素和植被的关系。结果显示:就土壤有机碳含量,在0～5cm、5～1 5cm和1 5～30cm土层,低海拔(2200m)和高海拔(3600m)处较低,中间海拔(3000～3500m)处较高;灌丛草甸森林高寒草甸干旱草原荒漠草原(P0.05)。就土壤全氮含量,0～5cm和5～1 5cm土层,3400m和3500m处较高,2200m和2800m处较低;1 5～35cm土层,3400m处较高、2200m和2800m处较低;0～5cm土层,灌丛草甸高寒草甸森林干旱草原荒漠草原;5～1 5和1 5～35cm土层,灌丛草甸森林高寒草甸干旱草原荒漠草原(P0.05)。就土壤碳氮比,在0～5cm、5～1 5cm和15～30 cm土层,3000m和3200m处最高;2300m和2800m处最低;森林灌丛草甸高寒草甸干旱草原或荒漠草原。土壤有机碳和全氮含量及碳氮比总体上都随年均温度增加而降低,随年降水量增加而增加。不考虑海拔差异,0～5cm、5～1 5cm和1 5～30cm土层土壤有机碳和全氯含量相关系数较高;考虑海拔差异,在不同土层和海拔的差异较大。     

Root zone soil nitrogen management to maintain high tomato yields and minimum nitrogen losses to the environment

Greenhouse field experiments on tomato were carried out at Shouguang, Shandong province, over four double cropping seasons between 2004 and 2008 in order to understand the effects of manipulating root zone N management (RN) on fruit yields, N savings and N losses under conventional furrow irrigation. About 72% of the chemical N fertilizer used in conventional treatment (CN) inputs could be saved using the RN treatment without loss of yield. The cumulative fruit yields were significantly higher in the RN treatment than in the CN treatment. Average seasonal N from irrigation water (118 kg N ha⁻¹), about 59% of shoot N uptake, was the main nitrogen source in treatments with organic manure application (MN) and without organic manure or nitrogen fertilizer (NN). N losses in the RN treatment were lowered by 54% compared with the CN treatment. Lower N losses were found in the MN and NN treatments due to excessive inputs of organic manure and fruit yields were consequently substantially affected in the NN treatment. The critical threshold of N_min supply level in the root zone (0–30 cm) should be around 150 kg N ha⁻¹ for sustainable production. April to May in the winter–spring season and September to October in the autumn–winter season are the critical periods for root zone N manipulation during crop growth. However, control of organic manure inputs is another key factor to further reduce surplus N in the future.     

包头工业区蔬菜重金属富集及人群健康评价

利用电感耦合等离子体原子发射光谱,测定内蒙古包头南海子工业区的土壤和芹菜、叶用莴苣、菠菜、芫荽、油麦菜、大白菜、普通白菜等7种主要蔬菜中Hg、Se、Zn、Cu、Pb、Mn、Cd等重金属含量,并对土壤污染程度和7种蔬菜的食用健康风险进行评价。结果表明:包头南海子工业区的土壤受到中度重金属污染,其中Hg和Se污染非常严重;Zn、Mn、Cu向蔬菜中迁移的能力较大;不同种类蔬菜对重金属的吸收能力不同,其中Zn在除大白菜外的其他6种蔬菜中含量均超标,Cu在油麦菜中含量超标,Hg在芹菜、油麦菜和菠菜中含量超标,大白菜对各种重金属的吸收能力均较小,而油麦菜、菠菜、芹菜、叶用莴苣对这7种重金属的富集程度普遍较高,与其他蔬菜相比食用风险较大;儿童的摄食健康风险高于成人。     

Effects of floral and foliar application of plant growth promoting rhizobacteria (PGPR) on yield, growth and nutrition of sweet cherry

During 2003 and 2005, plant growth promoting effects of Pseudomonas BA-8 and Bacillus OSU-142 were tested alone or combinations on sweet cherry (Prunus avium L.) cv. 0900 Ziraat in terms of yield, growth, nutrient composition of leaves in the province of Konya, Turkey. The presence of Pseudomonas BA-8, Bacillus OSU-142 and BA-8 + OSU-142 stimulated plant growth and resulted in significant yield increase. Floral and foliar applications of BA-8, OSU-142 and BA-8 + OSU-142 in sweet cherry significantly increased yield per trunk cross-sectional area (16.3, 10.9 and 21.7%), fruit weight (4.15, 5.37 and 1.24%) and shoot length (11.3, 11.8 and 29.6%), respectively, compared with the control. In addition, N, P and K contents of sweet cherry leaves with BA-8, OSU-142 and BA-8 + OSU-142 treatments, Fe and Zn contents of leaves with BA-8 + OSU-142 treatment and Mn content of the leaves of sweet cherry with BA-8 and OSU-142 applications significantly increased. Nitrogen, P and K contents in leaves were determined to be increased from 2.00, 0.17 and 0.43% in the control to 2.19, 0.20 and 0.54% by BA-8 application, to 2.32, 0.24 and 0.54% by OSU-142 application and to 2.43, 0.22 and 0.51% by BA-8 + OSU-142 application, respectively. Co-inoculation of BA-8 + OSU-142 increased Fe and Zn contents of leaves up to 50.5 and 35.5% compared with the control, respectively. Manganese content of leaves significantly also increased by BA-8 (26.6%) and OSU-142 (27.0%) applications compared with the control. The results of the present study suggested that Pseudomonas BA-8 and Bacillus OSU-142 alone or in combination have a great potential to increase the yield, growth and nutrition of sweet cherry plant.     

Fennel swollen base yield and quality as affected by variety and source of nitrogen fertilizer

Two fennel (Foeniculum vulgare Mill.) varieties, Dolce and Azoricum, were field grown for swollen base (SB) production to select the most productive variety and the most suitable source of N fertilizers in fields supplemented with cattle manure, calcium superphosphate and potassium sulfate. Plants were then grown either with or without one of the synthetic N fertilizers, ammonium sulfate (AS), ammonium nitrate (AN) or urea applied at a rate of 170 kg N ha⁻¹.Plants of var. Dolce were heavier in fresh weight and produced swollen bases (SBs) of 25% higher marketability percentage, 143% yield increase and 50% more oil content as compared to Azoricum. The increased SB yield and quality in var. Dolce were due to its lower bolting tendency as compared to var. Azoricum. Among all measured parameters, bolting tendency and SB oil content proved to be variety-dependent since both parameters showed no responses to N fertilizer source.When N was applied as a synthetic source, SB yield and quality were markedly reduced with about a 36% increase in SB nitrate content as compared to the control. The lowest SB yield and quality were obtained when AN or urea was used. Although AS produced a comparable yield to that of the control, the physical quality of the harvested SBs was adversely affected. The major compound in SB essential oil, trans-anethole, increased only with AN source in var. Dolce but fluctuated in var. Azoricum. The second most common compound, para-anis-aldehyde in var. Dolce or limonene in var. Azoricum, however, was markedly reduced with the application of any synthetic N source.It is suggested, therefore, that var. Dolce is more recommended for SB production than var. Azoricum. Fertilizing with synthetic N sources during plant growth and development is not advised when the soil has already been supplemented with organic nitrogen as not only are SB yield, quality and flavor reduced but also its safety for human consumption.     

Effect of postharvest desiccation at high temperature on soluble sugar changes of two supersweet sweet corn cultivars

The alteration in the soluble sugar contents of two commercial cultivars of sweet corn, Zea mays L. Supersweet Jubilee and Sweetie, desiccated at 60°C was determined. The loss of kernel moisture under field condition was gradual, but was rapid under laboratory condition at 60°C. Constant dry weight of kernels was reached after 24 h. In both cultivars, postharvest desiccation at 60°C significantly increased raffinose and fructose contents over those of non-desiccated control. Sucrose content of kernels, however, was significantly decreased by desiccation in both cultivars. In cv. Supersweet Jubilee, raffinose, sorbitol, fructose and glucose were significantly increased in kernels contained in plastic bags held at 60°C compared with naked desiccation at 60°C. In cv. Sweetie, however, only fructose and glucose contents were increased and not raffinose, sorbitol or sucrose. It was concluded that high temperature desiccation had a profound effect on sweet corn soluble sugars which may be associated with their cell membrane protecting role.     

Effect of short-term exposure to high-temperature on total gene expression in the leaves of four raspberry (Rubus idaeus L.) cultivars

Summary

The effect of high temperature stress (27ºC or 37ºC for 24 h) on total gene expression profiles in the annual-fruiting raspberry (Rubus idaeus L.) cultivars ‘Autumn Bliss’, ‘Autumn Treasure’, ‘Erika’, and ‘Polka’ were evaluated at the floral initiation stage using a customised Rubus microarray. Significantly affected genes were obtained by pairwise t-tests using ‘volcano plots’ for each cultivar × treatment. A 10ºC elevation in temperature altered levels of expression, in at least one cultivar, of 644 differentially expressed genes in total, with ‘Erika’ and ‘Autumn Treasure’ showing elevated expression of 38 genes compared to ‘Autumn Bliss’ and ‘Polka’. We identified 12 common candidate genes that were modulated differentially in ‘Autumn Bliss’ and ‘Erika’ at 37ºC compared to 27ºC. In addition, two aquaporin genes (PIP1 and TIP2) were down-regulated in ‘Autumn Bliss’, but up-regulated in ‘Autumn Treasure’, ‘Polka’, and ‘Erika’ at 37ºC. Other down-regulated genes from the list of 38 genes included those encoding major latex-like proteins, plasma membrane proteins, cysteine rich proteins, and other stress-related proteins. Validation by real-time quantitative RT-PCR (RT-qPCR) indicated subtle changes in differential gene expression, suggesting a mild response to heat stress. This study used molecular tools to increase our understanding of, and to identify candidate genes involved in, the heat stress response of four annual-fruiting raspberry cultivars.     

设施果类蔬菜土壤EC 值动态及盐害敏感性分析

在建立饱和及土水比1∶5（m∶v）条件下EC_e 与EC_1:5 相关关系的基础上,建立EC_1:5 的土壤盐分分级指标,评价了传统管理条件下设施越冬长茬和春茬的土壤盐分动态。结果表明：设施菜田土壤ECe 与EC_1:5 呈极显著正相关,在京郊土壤条件下换算公式为EC_1:5 =0.105 ECe;果类蔬菜中茄子和辣椒属敏感蔬菜作物,苗期和全生育期耐盐性根层土壤EC1∶5 临界值分别为0.10 dS·m -1 和0.30 dS·m ^-1,当季根层土壤EC1∶5 可接受调控范围为0.30～0.50 dS·m ^-1;番茄和黄瓜属非敏感蔬菜作物,苗期和全生育期耐盐性根层土壤EC_1:5 临界值分别为0.30 dS·m ^-1 和0.60 dS·m ^-1,当季根层土壤EC1∶5 可接受调控范围为0.60～0.90 dS·m ^-1;日光温室越冬长茬土壤EC_1:5 均值从定植至翌年3 月一直稳定在0.30～0.34 dS·m ^-1 之间,之后逐渐下降,7 月降至0.15 dS·m ^-1;塑料大棚春茬定植后根层土壤EC_1:5 逐渐下降,4 月之前为0.29～0.30 dS·m ^-1,7 月降至0.20 dS·m ^-1;结合蔬菜作物耐盐指标发现,传统管理条件下日光温室越冬长茬和塑料大棚春茬蔬菜作物在苗期易出现盐害问题;越冬长茬敏感蔬菜作物从定植至翌年3 月期间,土壤盐度易超过其耐盐临界值,需要合理水肥调控以防盐害。     

有机肥对菜豆产量及土壤培肥效果的研究

采用随机区组设计,以鸡粪、猪粪为变量因素,进行有机肥对菜豆产量和土壤养分的影响研究。结果表明:菜豆施鸡粪以1667kg/1000m2、猪粪以1500kg/1000m2为2种有机肥的最佳施肥水平,产量分别达到1018、991kg/1000m2。施入有机肥可以增加土壤中速效N、P、K和有机质含量,随着施用量的增加而增加,增强了土壤肥力。