The Significance of NPK Fertilizers on Yield and Smut Incidence of Corn

The significance of N, K and P fertilizers on corn yield and smut incidence was evaluated in the field during the seasons 1988 and 1989. Rates of fertilizers were 30, 60 and 90 kg N/acre; 0, 50 and 100 kg K₂O/acre and 0 and 30 kg P₂O₅/acre. The corn plants were artificially inoculated with U. maydis spore suspension at 6-leaf growth stage. The results showed that N fertilization acted to enhance N content of ear-leaf and smut index and imposed depressing effects on leaf K. Unlike N, enhanced K-fertility performed opposite results on leaf N and smut index. A significant N x K interaction was detected on ear-leaf K and smut index, due to the antagonistic effects between ions. Grain yield data showed positive response to each N, K and P application, but the effect was much greater at the highest application rates. Yield losses were clearly pronounced, along all of the applied nutrient fertilizers, on plants where galls are located above ear than those with galls below ear. On average, the relative losses were 12.8 and 5.9 %, respectively, compared with 3.7 % for the main plot treatment. The 2-way interaction (except N × P) showed variable effects on yield performance.     

史丹利大量元素水溶性肥料对小白菜产量和品质的影响研究

为研究在水溶性肥料中添加多种微量元素对蔬菜产量和品质的影响问题,以小白菜为试验材料,采用盆栽试验方法对添加多种微量元素的史丹利20-20-20大量元素水溶性肥料在其产量和品质方面的影响进行了研究。研究结果表明:施用史丹利大量元素水溶性肥料的小白菜形态指标及品质指标均优于普通大量元素水溶性肥料及硫基复合肥料处理。史丹利20-20-20大量元素水溶性肥料处理小白菜整个生育期叶色浓绿,茎秆粗壮,其根长、株高、叶片数及叶片宽度均明显高于对照处理,且处理间差异明显;史丹利20-20-20大量元素水溶性肥料处理维生素C含量,较普通水溶性肥料、17-17-17硫基复合肥料对照分别提高8.8%、15.1%,可溶性糖含量分别提高9.4%、11.8%,可溶性蛋白含量分别提高9.2%、10%,对比组间差异具有统计学意义;硝酸盐含量与对照相比明显下降,分别降低7.9%、10%;小白菜鲜重,较对照分别增产8.8%、13.1%,增产效果显著。综上所述,施用添加多种微量元素的史丹利大量元素水溶性肥料对小白菜的生长发育具有较显著促进作用,可提高小白菜维生素C、可溶性糖、可溶性蛋白的含量,降低硝酸盐含量,明显改善小白菜的品质,增加小白菜的产量。     

土壤扩蓄增容肥对小麦产量及品质的影响

2012—2013年在陕西三原县（水地）和永寿县（旱地）进行土壤扩蓄增容肥应用效果试验,研究了土壤扩蓄增容肥对小麦产量、产量构成因素和品质的影响。结果表明,土壤扩蓄增容肥对冬小麦有极显著的增产作用。水地较对照净增产1304.06 kg/hm²,增产幅度为16.8%;旱地较对照增产224.70 kg/hm²,增产幅度为8.6%。同时,土壤扩蓄增容肥处理的水地小麦多个品质指标较对照显著降低,其中蛋白质含量降低4.2%,硬度降低2.2%,湿面筋含量降低4.6%,沉降值降低11.6%,面团流变学特性中除吸水率外均显著减少;但土壤扩蓄增容肥对旱地小麦品质指标无显著影响。     

Effects of Nitrogen and Foliar Sulphur Interaction on Grain Yield and Yield Components in Barley

In this study, conducted from 1979 to 1986 in southern Spain, the objective was to analyze the effects of a possible interaction between soil-applied N and foliar S applied to barley (Hordeum vulgare L.) during tillering on grain yield and to identify the mechanism involved. From 1979 to 1982, we used rates of 20, 40, 60 and 80 kg a.i. N ha^?1, together with 12.5 or 25 kg foliar a.i. S ha^?1 during tillering. The results demonstrated that foliar S at both dosages acted as a partial (but not total) substitute for N, when the latter was applied at levels of 40 to 60 kg ha^?1. These effects of S did not appear to result only from a nutritive mechanism, but rather from a hormonal mechanism through the increase in ethylene biosynthesis. Therefore, during 1983 to 1986, we used 40, 60 and 80 kg a. i. N ha^?1, together with 12.5 a. i. S ha^?1 and 0.55 kg a.i. ethrel (2-chloroethyl-phosphonic acid) ha^?1. The results showed that the effects of S and ethrel on yield were practically the same. Assayed with 40 and 60 kg N ha^?1, S and ethrel acted as partial (but not total) substitutes for N, exceeding the yield of the control without S or ethrel, and equalling the yield obtained with 20 kg more of N ha^?1. The S or ethrel applied with 80 kg N ha^?1 presented an additive effect with the N. The increases in yield using S or ethrel were in all cases due to the increased final number of spikes m^?2, which was principally a consequence of the higher number of tillers formed but also a result of increased survival of tillers to form a viable spike. In addition, the positive effects of S on yield were greater the smaller the N dosage and the lower the annual yield. Finally, we present a possible mechanism of hormonal action, to explain how foliar S applied during tillering affects grain yield in barley.     

Yield and Yield Components from Intercropping Improved Bush Bean Cultivars with Maize

Bush bean ( Phaseolus vulgaris L.) is widely intercropped with maize ( Zea mays L.) in North-west Spain. Little information is available on the relative performance of elite bush bean cultivars when intercropped or on the effect of bush bean on performance of the maize crop. This two-environment study presents the interactions between improved bush bean cultivars and maize on yield and yield components. Eight treatments (four bean/maize intercrops and four sole crops, two of bean and two of maize) were tested using a randomized complete block design with four replications in two environments. Bean and maize were planted simultaneously in alternate rows when intercropped. Significant treatment differences were observed for bean and maize moisture, pod and cob percentage, bean and maize yield, ears per plant and ear length. Location effects were significant for bean and maize moisture and pod percentage. Significant treatment by location interactions occurred for pod percentage and ear length. Intercropping reduced yield by between 40 and 60 % for bush bean cultivars, and by 45 % for both maize cultivars. Mean yields were used to calculate the land equivalent ratio (LER), which averaged 1.01 in Pontevedra but 0.93 in La Coruña. Intercropping of bush bean with maize did not make better use of land than conventional sole cropping under these environmental conditions. It is suggested that this was probably due to the amount and distribution of rain in relation to crop growth. Approaches that might be expected to result in improved land usage are presented.     

叶面肥(药)对苜蓿产量和质量的影响评价

为了推动草业的大力发展,提高苜蓿草产量和质量,增加种植苜蓿的效益,笔者进行了苜蓿生长期喷施叶面肥和植物生长调节剂试验,从供试的5种叶面肥（药）中筛选出了2种适合苜蓿生长的叶面肥。试验证明叶面喷施磷酸二氢钾和澳优对苜蓿具有明显的增产效果,且能显著提高粗蛋白含量、降低粗纤维的含量,其增产效果达20%以上,粗蛋白含量提高9.37%~10.62%、粗纤维的含量降低5.91%~4.36%。因此,在苜蓿生长期推荐使用磷酸二氢钾和澳优进行叶面处理,喷施浓度分别为1000倍和500倍。     

不同比例有机无机肥配施对水稻产量与氮素利用率的影响

探讨中药渣有机肥氮替代化肥氮不同比例对水稻生长发育、水稻产量及氮肥利用的影响,以期为水稻提质增效和实现有机废弃物的资源化利用提供新思路。在总施氮量不变的情况下,以中药渣有机肥为供试材料,设置不施肥对照(CK)和有机肥氮替代化肥氮0%、25%、50%、75%、100% 6个处理,研究有机肥氮替代化肥氮不同比例对水稻产量和氮肥利用率的影响。试验结果表明,在等氮量下以合理比例有机肥氮替代化肥氮有利于提高结实率、增加有效穗数。25%有机肥替代化肥增产最高,比单施化肥增产9.06%。本试验条件下,回归计算有机肥氮部分替代化肥氮比例为35.3%,产量可达到9057 kg/hm²,有机氮替代比例能显著提高水稻的生长和氮肥利用率。在农业生产实际中,等氮量替代条件下有机肥施用比例25%~35%是较理想的施肥比例。     

Physiological Investigation of the Impact of Nitrogen and Sulphur Application on Seed and Oil Yield of Rapeseed (Brassica campestris L.) and Mustard (Brassica juncea L. Czern. and Coss.) Genotypes

Field experiments were conducted to determine the physiological basis of the effects of N and S interactions on seed and oil yield of Brassica species. Five combinations of N and S (in kg ha⁻¹) 0S+100N (T₁), 40S+60N (T₂), 40S+100N (T₃), 60S+100N (T₄) and 60S+150N (T₅), were used for this purpose. Nitrate reductase (NR) activity and ATP-sulphurylase activity in the leaves were measured at various growth stages, as the two enzymes catalyse rate-limiting steps of the assimilatory pathways of nitrate and sulphate, respectively. The activities of these enzymes were strongly correlated with seed and oil yield. The highest nitrate reductase activity, ATP-sulphurylase activity and yield were achieved with the combination T₃ in both species. Any variation from this combination decreased the activity of these enzymes, resulting in a reduction of the seed and oil yield of Brassica species. The higher seed and oil yield achieved in these species at T₃ could be due to optimization of leaf soluble protein and photosynthetic rate, as these parameters are influenced by N and S assimilation.     

Investigation of Factors Determining Genotypic Differences in Seed Yield of Non-irrigated and Irrigated Chickpeas Using a Physiological Model of Yield Determination

Physiological attributes determining yield, both under drought and under irrigated conditions, of some advanced chickpea lines of recent origin were investigated over two seasons using a physiological model. Total shoot biomass, grain yield, and vegetative (D_v) and reproductive (D_r) durations were measured and the crop growth rates (C) and the rate of partitioning to seed (p) were estimated. The contribution of model parameters to variations in grain yield were determined by path analysis, and the relationships of the yield determinants with seed yield were obtained by regression techniques. The model was found to be suitable for chickpea, and when the parameters were fitted the model explained 98% of the variation. Irrigation enhanced D_r and C. While C was the major single yield determinant, the combination of C and p in non-irrigated environments explained most of the grain yield variation. D_v and D_r exhibited a negative relationship while C and p exhibited a positive relationship under drought stress and a negative relationship in the irrigated environment. There were indications of the existence of an optimum D_v for maximum C among the genotypes, suggesting the need to select for optimum duration genotypes. As high values for p and C in severe drought stress and D_r and C in the irrigated environments are advantageous for high yield, separate breeding strategies are needed for different soil water environments.     

控释氮肥对盆栽棉花产量及土壤养分状况的影响

通过盆栽试验,研究了硫加树脂包膜尿素(PSCU)和树脂包膜尿素(PCU)2种控释氮肥及普通尿素对棉花产量及土壤养分变化的影响。结果表明:控释氮肥一次基施较等氮量普通尿素一次基施子棉产量显著增加6.78%~28.91%,但与等氮量尿素基施40%加追施60%处理产量差异不显著。基施控释氮肥较尿素增加了棉花铃重,但对衣分和单株成铃数没有显著影响;且显著提高了盛花期和始絮期土壤中的硝态氮和铵态氮含量,同时也显著提高了初花期和盛花期土壤中的速效钾含量,但不同处理间有效磷含量差异不显著。因此,在盆栽条件下,控释氮肥一次基施既可满足棉花全生育期对氮素的需求,又在保障产量的前提下减少了追肥次数。     

The Effect of Short Warm Breaks during Chilling on Water Status, Intensity of Photosynthesis of Maize Seedlings and Final Grain Yield

The effects of short-term exposure of seedlings to suboptimal temperature (14 °C for 1 or 4 h in 24 h cycles) during chilling (5 °C for 12 days) on the water status and intensity of photosynthesis of tolerant (TG) and chilling-sensitive (SG) maize genotypes were studied. Daily warming for 1 or 4 h resulted in a decrease in the hydration of the seedlings to 31.1 % and 61.5 % (SG) and 14.8 % (TG) and 39.1 % (SG), respectively, in comparison with the continuously chilled control. During warming for 4 h, both genotypes absorbed water from soil in amounts that partly compensated for its loss through transpiration, after the plants had been moved to the lower temperature. A protective effect of shorter warming (1 h) on the hydration of the seedlings was a result of a strong, stomatal limitation of transpiration during the initial days of chilling. Warming for 1 or 4 h also increased the ability of TG stomata to close in reaction to water deficit in chilling conditions. The effect of increased temperature delayed the decrease of P_N in leaves and limited RGR inhibition of the seedling mass caused by chilling. Daily warming of plants at the seedling phase (14 and 20 °C for 1 or 4 h) reduced the unfavourable effect of chilling (5 °C for a period of 8 days) on the final yield, the filling of caryopses and their number in a cob after growth in natural conditions.     

Note on the Effect of Non-regular Spatial Patterns of Plants on Yield per Area Based on a Logarithmic Relationship between Single Plant Yield and Individual Area

Based on several simplifying assumptions, a previously developed stochastic approach allows an estimation of the effects of non-regular spatial patterns of the distribution of individual plants on yield per area (F). In this approach, two random variables were attached to each plant: single plant yield (E) and individual space per plant (A). The latter was estimated by the area of Thiessen-polygons. Yield per area was calculated theoretically by the expectation of the ratio E/A. Based on a logarithmic relationship between E and A the expectation of E/A can be expressed by an approximation which depends on the mean and on the variance of the individual plant spaces. An improvement of this approximation can be easily obtained by including skewness and kurtosis of the distribution of individual plant areas. Finally, all theoretical concepts and results were applied to an experimental data set of winter oilseed rape ( Brassica napus L.).     

NPK用量对露地西兰花产量、养分累积及肥料效率的影响

为了探讨露地西兰花的NPK合理施用量,提出科学的施肥配比。在宁夏引黄灌区通过田间试验研究了不同NPK供应水平对露地西兰花产量和地上部NPK吸收累积的影响,并评价了其肥料效率。结果表明：施用N、P肥对西兰花有显著增产作用,而施K处理间无显著差异。相对于N0和P0处理,增施N、P肥可分别提高23.6%~36.2%和7.6%~11.5%的经济产量。适当增施NPK肥能显著提高西兰花的地上部NPK养分累积。西兰花的肥料利用率、农学效率和偏生产力都随施肥量增加而降低。每施用1 kg N、1 kg P2O5、1 kg K2O分别可生产50.9~184.7、89.3~369.1、53.9~220.2 kg西兰花经济产量,其随施肥量增加呈显著降低趋势。西兰花经济产量与施N量(R2=0.886)、施P量(R2=0.906)和施K量(R2=0.794)都呈二次曲线关系。综合考虑蔬菜产量、养分累积和肥料效率,建议宁夏引黄灌区露地西兰花的施肥量分别为N 189.8~200.0 kg/hm2、P2O5 79.8~86.8 kg/hm2和K2O 80.2~112.5 kg/hm2 ,其施肥配比为1:0.42~0.43:0.42~0.56。     

Effect of Mulch from Selected Multipurpose Trees (MPTs) on Growth, Nitrogen Nutrition and Yield of Maize (Zea mays L.)

Leaf extracts and mulch from 14 multipurpose trees were used to test their effects on maize germination, growth and yield. Maize germination was significantly reduced by leaf extracts of all species with increasing extract concentration. The most drastic reductions were caused by Gliricidia sepium , Tetrapleura tetraptera , Lonchocarpus sireceus , Senna siamea and Leucaena leucocephala . Terminalia superba , Tetrapleura tetraptera , Pithecelobium dulce , Gliricidia sepium and Senna siamea significantly reduced maize root growth at the lowest extract concentration, while shoot length was most significantly reduced by Gliricidia sepium , Leucaena leucocephala , Alchornea coordifolia , Pithecelobium dulce , Terminalia superba , and Tetrapleura tetraptera at all concentrations. Growth of maize in pots and yield in the field were controlled by nitrogen supply and uptake. Fast-decomposing leaf material rich in nitrogen promoted growth and yield of maize. Thus Leucaena leucocephala and Gliricidia sepium , both nitrogen-fixing legumes with high nitrogen contents and fast-decomposing leaf materials, significantly increased maize growth and yield. This suggests that the negative effects of leaf extracts observed in the laboratory are ecologically irrelevant in the field.     

Effects of Irrigation at Different Growth Stages and Source-Sink Manipulations on Yield and Yield Components of Mung Bean, Vigna radiata (L.) Wilczek, in Dry and Intermediate Zones of Sri Lanka

Irrigation is a management option available to farmers in the subhumid zones of Sri Lanka to increase mung bean yields during the dry Yala season. The objective of this study was to quantify the yield gain in response to irrigation at different stages of the crop and thereby determine the most suitable stage/s of irrigation. Four field experiments were conducted during Yala in 1995 and 1996 at two sites, Maha-Illuppallama (MI) and Kundasale (KS). Eight irrigation regimes consisting of all possible combinations of irrigation at three growth stages of the crop were defined. The respective growth stages were vegetative (from germination to appearance of first flower), flowering (from appearance of first flower to 75 % pod initiation) and pod-filling (from 75 % pod initiation to maturity). The treatments which received irrigation during two or more stages had significantly higher yields (793–1396 kg ha⁻¹) than those which received irrigation during only one stage (401–756 kg ha⁻¹) with the lowest yield being shown by the rain-fed treatment (227–396 kg ha⁻¹). When at least two stages can be irrigated, irrigation during the flowering and pod-filling stages was most effective. Irrigation during flowering produced the highest yield gain when only one stage could be irrigated. Seed yield showed a strong positive correlation with number of pods m^−2. Fifity per cent de-podding caused yield reductions at both sites, indicating sink limitation. In contrast, 50 % defoliation reduced the yields only at MI where the number of pods m⁻² was greater than at KS. Hence, source limitation was present only when the number of pods was higher.     

不同控释肥养分释放特征及对番茄根系生长、产量与品质的影响

为了探讨不同释放期控释肥在设施蔬菜上的应用效果,通过尼龙网袋田间试验模拟研究不同控释肥的养分释放规律,并在番茄上试验研究不同释放期控释肥对番茄根系生长、产量及品质的影响,同时进行经济效益分析。结果表明：控释尿素(CRU)、控释肥(CRF)能够较长时间维持番茄根系活力水平,从而促进番茄增产和品质改善。在氮、磷、钾施用量相同的条件下,CRU、CRF较普通复合肥(CCF)番茄产量增加7.8%~15.7%;除控释肥CRF-A外,净收益增加2287.5~10677.0元/hm²;不同释放期控释肥料对番茄品质的影响不同,CRU、CRF-B、CRF-C的番茄Vc含量均高于CCF处理增加2.7~4.8 mg/kg,各施肥处理番茄糖酸比均低于对照。说明控释肥提高番茄产量和品质的原因是促进番茄采收期根系生长及较高的活力水平。     

磷肥种类对弱筋小麦产量和品质的影响

在缺磷土壤（速效磷含量低于6.37 mg/kg）上研究不同磷肥种类对弱筋小麦籽粒产量及品质的影响.结果表明：施用不同种类磷肥均能提高籽粒产量;不同磷肥品种间以复合肥增产效果最高,过磷酸钙最低;不同磷肥处理的籽粒蛋白质含量均符合国家标准（GB/T17893-1999）.不同磷肥对弱筋小麦的营养品质和加工品质有显著的调节作用,以施用复合肥对弱筋小麦提高产量和改善品质效果最佳.     

密度与施肥对玉米品种黔单24产量的影响

试验以杂交玉米黔单24为试材,采用四因素五水平二次回归正交旋转组合设计,研究种植密度及氮磷钾肥施用量对玉米产量的影响.研究结果表明,在黔西南地区杂交玉米黔单24单产达到730.27kg/667m2以上的最佳高产栽培措施为：种植密度4170～4294株/667m2,氮肥22.78～25.7kg/667m2,磷肥13.75～16.25kg/667m2,钾肥9.335～11.005kg/667m2.     

Results of Long-term Experiments with Growing Flue-cured Tobacco (Nicotiana tabacum L.) in Monoculture and Different Types of Crop Rotations

In broadly conceived long-term experiments, tobacco was grown in monoculture and with different crop rotations. This paper presents results in terms of the yields achieved and the major yield components for the crops grown, and the proportion of particular tobacco quality classes obtained. In addition to tobacco monoculture (initially only fertilized and later also unfertilized) as the key crop, different types of crop rotations included, besides tobacco, the following crops: winter wheat, maize, soybean, oil-seed rape, and red clover. Experiments involved two 2-year and two 4-year crop rotations, and a 3-year, a 5-year, and a 6-year crop rotation. Experiments were set up on luvic semigley on multilayered Pleistocene sands. Average 10-year results suggest that there is an advantage of crop rotation over monoculture for tobacco leaf yields. The influence of different crop rotation types on yields of other crops was variable, tending towards higher values as the number of crops in rotation was increased. Values obtained for yield components should be considered from two angles: some of the values were primarily influenced by genetic factors, while others were influenced by ecological factors, including crop rotation as an overall biological buffer. With regard to quality classes (IB-III), the growing of flue-cured tobacco in crop rotation represents a great advancement relative to its growth in monoculture, even in a narrower crop rotation.     

食葵氮磷钾肥对产量相关性状的影响及经济效益分析

为研究氮、磷、钾肥对食葵产量及产量相关性状的影响,寻求最佳施肥量与经济效益之间的平衡点,采用“3414”设计通过3年田间试验,建立了氮、磷、钾肥与产量及产量相关性状的效应函数,结果显示：3种肥料对食葵产量影响排序为钾>氮>磷,对百粒重和单盘粒重影响排序均为钾>磷>氮,氮、磷、钾肥对产量、百粒重、单盘粒重的单因素效应均呈先升高后下降的趋势。两因素互作中,PK互作的产量最高。最高产量的施肥组合为氮肥61.5 kg/hm²、磷肥35.0 kg/hm²、钾肥50.1 kg/hm²、产量2309.0 kg/hm²,产投比13.8;最经济产量的施肥组合为氮肥57.5 kg/hm²、磷肥34.9 kg/hm²、钾肥47.9 kg/hm²、产量2307.8 kg/hm²,产投比14.3。最经济产量施肥量较少,肥料成本低,产值低,收入高,产投比高。