Effect of different levels of nitrogen and farmyard manure on yield and quality of spinach (Spinacea oleracea L.)

The effect of different levels of nitrogen N₀(0kg/ha), N₁(30 kg/ha), N₂ (60 kg/ha), and N₃ (90 kg/ha) and farmyard manure F₀ (0 tonnes/ha), F₁ (10 tonnes/ha), and F₂ (20 tonnes/ha) on the yield and nutrient composition of spinach and its uptake was investigated on a sandy loam soil. Yield; phosphorus, iron, manganese, zinc, and copper uptakes; and ascorbic acid content increased with the application of both the inorganic nitrogen fertilizer and the farmyard manure, with a maximum at the N₃F₂ level, i.e. at 90 kg N/ha with 20 tonnes FYM/ha. However, the contents of protein, -carotene, and reducing sugars were maximum at the highest dose of nitrogen without the application of farmyard manure.     

氮硅配施对夏玉米抗倒性和产量的影响

试验采用N、Si(3×2)完全均衡方案和田间裂区设计,氮肥设120 kg/hm2(N1)、180 kg/hm2(N2)、240 kg/hm2(N3)3个水平,硅(SiO2)设0、75 kg/hm2两个水平,研究氮硅配施对夏玉米抗倒性和产量的影响。结果表明,施氮量为120~240 kg/hm2,玉米平均株高、茎粗、茎皮厚、室内横折强度、田间抗拉弯强度、穗长、穗粗、穗粒数、百粒重、理论产量和实际产量均随施氮量的增加而提高,不同施氮水平间上述各指标均达极显著差异(P<0.01)。氮硅配施对玉米茎粗、茎皮厚、室内横折强度和田间抗拉弯强度影响的交互效应达显著水平(P<0.05),N1、N2水平下,施硅与不施硅处理相比茎粗、茎皮厚、室内横折强度、田间抗拉弯强度差异达显著水平;N3水平下,除室内横折强度达显著水平外,其他各指标差异均不显著。氮硅配施对玉米穗长、穗粗、穗粒数、百粒重、理论产量和实际产量影响的交互效应亦达显著或极显著水平,N1、N2水平下,施硅与不施硅处理相比穗长、穗粒数、理论产量、实际产量差异达显著水平;N3水平下,各指标差异不显著。     

玉米施肥量优化模型与土壤无机氮变化特征

对"3414"田间试验各处理玉米产量和不同氮水平(N0=0、N1=93.75、N2=187.5、N3=281.25 kg/hm~2)下测定土壤无机氮,探究N、P、K不同配比施肥对玉米产量的影响和不同氮水平下土壤无机氮的变化特征。结果表明,施氮对玉米产量的影响达到差异显著水平,施磷、钾肥对玉米产量的影响差异不显著。随着施氮量升高,玉米产量先升高后稳定,通过方差分析确定当地最佳推荐施氮量变化范围为93.75～281.25 kg/hm~2。施氮可以提高1 m土壤中铵态氮和硝态氮的积累量。铵态氮易被固定,拔节期以后,土壤中铵态氮积累较为稳定。硝态氮在土壤中变异较大,尤其在高施氮量(281.25 kg/hm~2)时,1 m土体中硝态氮积累量显著增加。无机氮总量与施氮量显著相关,当施氮量为281.25 kg/hm~2时,大大增加中期(抽雄期)氮素损失风险,确定安全施氮量处于187.5～281.25 kg/hm~2。提高产量、减少氮素损失的生产目标,207.27 kg/hm~2的施氮量为当地经济安全施氮量。     

生物炭还田条件下磷肥减施对玉米产量及养分利用的影响

通过4年田间定位试验,研究辽宁昌图棕壤区生物炭还田条件下磷肥减施20%对玉米产量及养分利用的影响。结果表明,与常规施肥相比,生物炭还田(3 000 kg/hm~2)后各处理促进玉米增产,最高增产5.5%,生物炭还田配施磷肥减量20%处理的产量表现略有增加的趋势。生物炭还田后各处理均提高了玉米植株N、P和K的养分吸收量,提高玉米植株氮素和磷素回收率,生物炭还田配施常规肥处理可更好促进玉米氮、磷、钾养分吸收,提高玉米氮素回收率,4年综合提高5.3个百分点;生物炭还田配施磷肥减量20%处理可更好提高玉米磷素回收率,提高4.9个百分点。     

间作条件下玉米与马铃薯的养分利用特征

采用田间小区试验,通过2行玉米间作2行马铃薯、4行玉米间作4行马铃薯及相应单作试验,在玉米拔节期和大喇叭口期比较植株氮磷钾浓度和养分吸收量,研究玉米间作马铃薯中养分吸收和肥料利用效率的变化。结果表明,玉米大喇叭口期,间作玉米植株氮钾浓度显著低于单作(F_氮=6.608,P_氮=0.015;F_钾=5.148,P_钾=0.028),且根、茎、叶中氮磷钾浓度都低于单作处理,部分差异达到了显著水平,根对氮和磷的利用贡献大一些,茎对钾的利用贡献大。间作玉米的养分吸收量没有优势,但间作玉米单株产量极显著高于单作,产量与玉米大喇叭口期植株氮钾浓度极显著和显著负相关,表明提高玉米氮钾利用效率可促进增产。     

磷素施用对鲜食糯玉米养分积累分配和产量的影响

以苏玉糯5号和渝糯7号为试验材料,研究磷素施用(A:空白;B:一次性基施P2O575 kg/hm2;C:一次性基施P2O5150 kg/hm2;D:基施和拔节期追施P2O5各75 kg/hm2)对鲜食糯玉米产量、干物质和氮磷钾积累分配的影响。结果表明,穗粒数、子粒鲜重和干重随着磷素施用量增加均显著增加,鲜子粒产量升高,升幅D处理高于C处理。随着磷素施用量增加,植株干物质和氮磷钾积累量均显著升高,磷素施用量P2O5150 kg/hm2时,分次施用较一次性基施植株干物质量和氮、磷、钾积累量分别升高11.1%和16.2%、19.4%、34.5%。鲜食期植株干物质和磷素主要分配于子粒和茎秆,氮素主要分配于子粒和叶片,钾素主要分配于茎秆和叶片。逐步回归分析结果表明,苞叶中干物质分配比例较低、茎秆中氮素分配比例较高、叶片和子粒中磷素分配比例较高、叶片中钾素分配比例较高时有利于糯玉米鲜子粒高产。     

磷素施用对糯玉米子粒产量和磷素积累分配的影响

以苏玉糯5号和渝糯7号为试材,研究不同磷肥施用量和施用时期对糯玉米子粒产量及磷素积累分配的影响。结果表明,糯玉米成熟期子粒产量随施磷量的增加而增加,苏玉糯5号在基施和拔节期分别追施P_2O_575 kg/hm~2处理子粒产量最高;渝糯7号一次性基施P_2O_5150 kg/hm~2的处理子粒产量最高。随着生育进程的推进,两个品种植株磷素积累量均逐渐增加;同一生育时期下,两个品种植株磷素积累量随着施磷量的增加而增加。成熟期苏玉糯5号和渝糯7号两个品种在各施磷处理下子粒中磷素占植株整体的分配比例均最高,达70%左右;雄穗和苞叶中磷素含量相对最低,各仅占植株整体含磷量的2%左右。植株磷素利用效率在基施和拔节期分别追施P2O575 kg/hm~2处理下较低。综合两个品种产量、磷素积累和分配在不同处理的变化趋势,以基施和拔节期分别追施P_2O_575 kg/hm~2较优。     

The effect of phosphorus fertilization on the chemical quality of Katahdin potatoes

The influence of phosphorus fertilization on the content of ascorbic acid, lipids, total nitrogen, protein, and non-protein nitrogen of Katahdin potatoes was investigated. Phosphorus in the form of mono ammonium phosphate was applied at rates of 0, 56, 112, and 168 Kg/ha (0, 50, 100, and 150 lb/acre). Ascorbic acid, total nitrogen, protein and non-protein nitrogen content were significantly increased (p<.01) and the phospholipid content was significantly reduced (p<.01) by phosphorus application.     

In vitro bioavailability of iron from spinach (Spinacea oleracea) cultivated in soil fortified with graded levels of iron and zinc

A pot-culture experiment was conducted to assess the bioavailability of iron from spinach cultivated in soil fortified with graded levels of iron and zinc (FeSO₄ . 7H₂0 and ZnSO₄ . 7H₂0, respectively). Applications of varying levels of iron to soil increased the total iron and phosphorus contents and decreased the zinc content (P<0.05). The effect of applying varying levels of zinc was the opposite of on the minerals in spinach. The ascorbic acid content was remarkably reduced with varying levels of iron and zinc. Higher levels of zinc and lower levels of iron in the soil increased the bioavailability of iron from spinach (P<0.05). In conclusion, the interactions of 15 ppm zinc with 30 ppm iron significantly enhanced the bioavailability of iron, total iron and zinc contents.     

Tracing the fate of nitrogen with <Superscript>15</Superscript>N isotope considering suitable fertilizer rate related to yield and environment impacts in paddy field

While the application rate of nitrogen fertilizer is believed to dramatically influence rice fields and improve the soil conditions in paddy fields, fertilization with low use efficiency and nitrogen loss may cause environmental pollution. In this paper, ¹⁵N-labeled urea was used to trace the fate of nitrogen at four rates (0, 75, 225 and 375 kg N/ha) of urea fertilizer over three split applications in Hangzhou, Zhejiang, in 2014. Plant biomass, the soil nitrogen content of different layers, NH₃ volatilization and N₂O emissions were determined using the ¹⁵N abundance to calculate the portion from nitrogen fertilizer. The results indicated that rice yields increased with the application rate of nitrogen fertilizer. NH₃ volatilization is the main nitrogen loss pathway, and N₂O emissions were significantly associated with nitrogen application rates in the paddy. The percent of nitrogen loss by NH₃ volatilization and N₂O emissions increased with the nitrogen application rate. This study showed that the suitable N fertilizer in a loam clay paddy, considering the yield requirements and environmental issues, is approximately 225 kg N/ha in Hangzhou, with a distribution of 50.06% of the residual in the rice and soil and 48.77% loss as NH₃ volatilization and N₂O emissions. The nitrate from fertilization mainly remained in the 0–20 cm level of the topsoil.     

Exogenous ascorbic acid scarcely ameliorates inhibition of photosynthesis in rice leaves by O3

The role of ascorbic acid on acute O₃-induced inhibition of photosynthesis in solution-cultured paddy rice was evaluated. As pre-treatment, ascorbic acid (0, 5, and 10 mM) was added to the culture solution for 5 d before 5 h of O₃ exposure (0, .1, and .3 cm³ m^?3 O₃) during daytime. O₃ decreased photosynthesis-related parameters, total ascorbic acid content, and the redox state (RDS) of ascorbic acid. Ascorbic acid treatment enhanced the total ascorbic acid contents and its RDS level of rice leaves, but scarcely ameliorated O₃-induced inhibition of photosynthesis-related parameters. Inhibition of net photosynthetic rate (P_N) by O₃ was slightly ameliorated by exogenous ascorbic acid only at 1 d after O₃ exposure. These results indicate that ascorbic acid is a component of protection from O₃ injury but has a marginal role in the acute inhibition of P_N by O₃ in rice leaves.     

河西走廊灌溉玉米施肥现状评价与减肥对策

选取河西走廊灌溉玉米典型种植区张掖,连续2年进行农户调查玉米施肥现状及存在问题.结果表明,玉米产量两年平均为12 589 kg/hm2,两年均是中产等级的样本数占总样本数的比例最高.氮肥投入处于偏高(438～584 kg/hm2)和很高(＞584 kg/hm2)等级以上的占比为47％(2018年)和76％(2019年)...     

Effect of nitrogen and phosphorus application on soil nitrogen morphological characteristics and grain yield of oil flax

In order to identify effects of nitrogen (N) and phosphorus (P) on soil nitrogen morphological characteristics and grain yield of oil flax, a two-factor experiment was conducted in a randomized complete block design in typical semi-arid and hilly-gully area of Loess Plateau with 3 replicates in 2013 and 2014. Two levels of N application included 150 ​kg/hm² (N₂) and 75 ​kg/hm² (N₁). P application included 150 ​kg P₂O₅/hm² (P₂) and 75 ​kg P₂O₅/hm² (P₁). Temporal and spatial variation of soil nitrate nitrogen (NO₃⁻-N) and ammonium nitrogen (NH₄⁺-N) contents in 0–60 ​cm soil layer, and relationship between soil NO₃⁻-N accumulation (SNA) and grain yield of oil flax were analyzed. Results showed that SNA increased with evaluated N application rate in different soil layers (0–20 ​cm, 20–40 ​cm and 40–60 ​cm). With the increased P application, SNA increased at N₁ level but decreased at N₂ level. SNA under N₂P₁ treatment increased by 73.33% in 2013 and 74.97% in 2014 respectively, compared with control treatment (CK) at maturity stage. Grain yield of oil flax also increased by 44.27% in 2013 and 56.55% in 2014, compared with CK under the same treatment. Correlation analysis showed that SNA in different soil layers were respectively positively correlated with grain yield. In conclusion, this research suggested that the optimal fertilizer application rate was 150 ​kg ​N/hm² and 75 ​kg P₂O₅/hm² in the Northwest of China.     

东北西部地区春玉米施肥现状分析

对吉林西部6个乡镇和通辽市5个旗县共170份玉米养分调查数据进行分析和评价.结果 表明,吉林西部玉米平均单产8782 kg/hm2,氮、磷、钾养分平均投入量分别为199、96、94 kg/hm2,偏生产力分别为50、97、101 kg/kg;内蒙古通辽平均单产10200 kg/hm2,氮、磷、钾养分平均投入量分别为27...     

氮磷钾配比对高产夏玉米产量、养分吸收积累的影响

通过大田试验研究了高产夏玉米土壤养分限制因素及植株养分吸收积累规律。结果表明：各施肥处理均比不施肥显著增产,增产7.3%～15.9%,氮磷钾推荐施肥(OPT)处理产量最高,达到12 051.2 kg/hm²,增产1 651.2 kg/hm²;施用氮肥、钾肥能显著提高夏玉米的产量,N、K是高产夏玉米主要养分限制因素。高产夏玉米植株体内氮、磷、钾的积累量均随生育期的延长而增加,养分积累量的大小顺序为N>K>P,从拔节期至大喇叭口期是氮素、磷素和钾素吸收量和吸收速率最大的时期,整个生育期,高产夏玉米能持续吸收N、P、K养分。N当季回收率为18.05%,P₂O₅为14.55%,K₂O为18.34%,每生产100 kg经济产量需吸收的N、P₂O₅、K₂O的量分别为1.62、0.69、1.83 kg。     

不同施磷水平对春玉米产量、养分吸收及转运的影响

通过两年田间试验,研究不同施磷条件下玉米产量、养分吸收利用及转运的变化。结果表明,玉米产量随施磷水平的提高先增后降,以施磷90 kg/hm~2处理最高。依据玉米产量(y)和施磷量(x)二次曲线拟合,得出最佳施磷范围为90.1~103.1 kg/hm~2。在施磷水平30~90 kg/hm~2范围内,抽雄期各养分积累量与转运量呈正比;当施磷水平提高至120 kg/hm~2,各养分向子粒转运量出现负效应。相关分析表明,除苗期外,玉米其他生育期氮、磷、钾的积累间及转运间均存在显著或极显著的正向相关性,氮、磷、钾积累、转运与产量间也存在显著或极显著的正向相关性,灌浆期氮、磷、钾素积累与产量间的相关系数最大。玉米磷肥生理利用率和农学利用率随施磷水平的提高先增后降,玉米磷素吸收效率、当季回收率和偏生产力随施磷水平的提高而降低。     

北方设施菜地夏季休闲期甜玉米最佳行株距和播期研究

在北京市郊区设施菜地对夏季敞棚休闲期甜玉米不同株距和不同播期进行试验,研究高效吸氮、有效减少NO3--N淋溶同时有较好经济效益的甜玉米种植模式。结果显示,以83 cm大行距、50 cm小行距、26 cm株距为最佳行株距,吸氮量达289 kg/hm2,收获后0～200 cm土层NO3--N含量减少649 kg/hm2,鲜穗产量达到19 573kg/hm2,均显著优于其他行株距处理(P0.05)。甜玉米提前10 d播种(比休闲开始当日提前10 d)为最佳播期,吸氮量达到328 kg/hm2,收获后0～200 cm土层NO3--N含量减少357.7 kg/hm2,鲜穗产量达19 853 kg/hm2,显著优于其他播期处理(P0.05)。     

Effect of Phosphorus and Irrigation Levels on Yield,Water Productivity,Phosphorus Use Efficiency and Income of Lowland Rice in Northwest Pakistan

With decreasing availability of water for agriculture and increasing demand for rice production, an optimum use of irrigation water and phosphorus may guarantee sustainable rice production. Field experiments were conducted in 2003 and 2004 to investigate the effect of phosphorus and irrigation levels on yield, water productivity (WP), phosphorus use efficiency (PUE) and income of low land rice. The experiment was laid out in randomized complete block design with split plot arrangements replicated four times. Main plot consisted of five phosphorus levels, viz. 0 (P0), 50 (P50), 100 (P100), 150 (P150), and 200 (P200) kg/hm2, while subplots contained of irrigation times, i.e. 8 (I8), 10 (I10), 12 (I12), and 14 (I14) irrigation levels, each with a water depth of 7.5 cm. Mean values revealed that P150 in combination with I10 produced the highest paddy yield (9.8 t/hm2) and net benefit (1 231.8 US$/hm2) among all the treatments. Phosphorus enhanced WP when applied in appropriate combination with irrigation level. The highest mean WP [13.3 kg/(hm2?mm)] could be achieved at P150 with I8 and decreased with increase in irrigation level, while the highest mean PUE (20.1 kg/kg) could be achieved at P100 with I10 and diminished with higher P levels. The overall results indicate that P150 along with I10 was the best combination for sustainable rice cultivation in silty clay soil.     

Chlorophyll meter to predict nitrogen sidedress requirements for short-season cotton (Gossypium hirsutum L.)

A two-location experiment was carried out at five to six nitrogen levels to study the relationship between chlorophyll-meter readings (SPAD values) and physiological or yield traits in short-season cotton. The results showed that there were highly significant (P<0.01) linear relationships between SPAD values and contents of both nitrogen and chlorophyll at each growth stage, and as well as with the daily increase in plant height during early flowering. The relationship between nitrogen concentration and SPAD was stronger when nitrogen was expressed on a leaf area (N_a) rather than on a dry weight (N_dw) basis. Significant curvilinear relationships were found between SPAD values at various stages and photosynthetic intensity, lint yield, and total boll number per hectare, respectively. Furthermore, the linear regressions between SPAD values and N fertilizer levels were highly significant (P< 0.01), and before the boll opening stage, the slopes of these regressions were similar (0.040–0.041) at the two locations. These data provided evidence that the chlorophyll meter could be used to determine sidedress N requirements of short-season cotton before boll opening stage. Critical SPAD levels for maximum lint yield were established as 32.4, 33.1, 35.0, 43.55, and 39.7 at early flowering, flowering peak, boll forming, the beginning of boll opening and boll opening stages, respectively. It was also established that 24.2–25.0 kg ha⁻¹ increase in N application should be necessary for each unit decrease in SPAD value below the critical level.     

施氮量对半湿润区小麦-玉米轮作系统土壤氮的影响

为探讨不同施氮量对黄土高原半湿润地区冬小麦-夏玉米轮作系统土壤氮动态变化的影响,2016-2018年采用田间试验,研究了不同氮肥用量下冬小麦-夏玉米轮作系统作物不同生育时期0～200 cm土层土壤氮的动态变化。结果表明,不同氮肥处理间0～60 cm土层土壤全氮储量差异显著,两年试验后较试验前,施氮0 kg·hm~(-2)(N_0)、100 kg·hm~(-2)(N_(100))、200 kg·hm~(-2)(N_(200))、300 kg·hm~(-2)(N_(300))和400kg·hm~(-2)(N_(400))处理的土壤全氮增量分别为-180、-245、288、627和709 kg·hm~(-2)。不同氮肥处理间0～200 cm土层土壤硝态氮含量及其储量差异显著,土壤铵态氮含量无显著性差异。两年试验后较试验前,N_0和N_(100)处理0～200 cm土层土壤硝态氮储量明显降低,N_(200)处理变化不显著,3者均无明显硝态氮下移,而N_(300)和N_(400)处理0～200 cm土层土壤硝态氮储量显著增加,向深层土壤(100～200 cm)下移明显。每季作物施氮200 kg·hm~(-2)可以减少深层土壤硝酸盐累积量。