Relationship between corn leaf composition and high and low yield levels

Abstract

Corn yields and leaf samples were obtained from experimental plots receiving varying rates of N, P, and K. Yields were placed in two groups. One group consisted of yields < 134 bu/A, and a second group consisted of yields ≥ 134 bu/A. Within each group yields were regressed on leaf levels of N, P, K, Ca, Mg, B, Cu, Fe, Mn and Zn as independent variables in a second order polynomial. Using stepwise regression procedures the fit of the polynomial was determined for each set of observations, and statistical significance of various effects was determined.

The regression accounted for 71.5 percent of observed variability in yields in the < 134 bu/A category, and 53.2 percent of observed variability in yields in the ≥ 134 bu/A category. With statistical criteria used, twelve interactions were observed in both groupings, but the PFe interaction was the only one common to both analyses. Seven interactions with Mn were observed in the lower yield category, but only one in the upper category. One linear effect and three quadratic effects were observed in the lower yield category, and three linear effects and four quadratic effects were observed in the upper yield category.     

A comparison of the chemical composition of the corn leaf and the grain sorghum leaf

Abstract

Leaf samples were taken from corn and grain sorghum being grown in adjacent fields with the same soil type and with the same cultural practices insofar as possible. The samples were analyzed for N, P, K, Ca, Mg, Fe, Zn and Mn. Results show that the nutrient composition of the leaves of corn and grain sorghum were consistently different for most nutrients. The differences were sufficiently great and consistent to strongly suggest that critical nutrient levels need to be established for grain sorghum instead of using diagnostic criteria established for corn.     

Effect of corn cultivar,phosphorus and potassium on yield and chemical composition

A corn cultivar × P × K factorial experiment was conducted to evaluate differential responses of selected parameters to P and K soil fertility. Yield along with leaf nutrient concentration of some nutrients differed among cultivars and nutrient concentration of some elements was affected by soil fertility. Leaf K and Mg were more consistently affected by K fertility than other variables studied. Fertility effects upon micronutrient leaf concentration were not consistent among cultivars or between years.     

A comparison of the relationship between corn yield and nutrient concentration in whole plants and different plant parts at early tassel at two locations

Abstract

The relationship between corn yield and nutrient composition of whole plants at two stages of growth, and between corn yield and nutrient composition of different plant parts at early tassel was investigated. It was found that chemical composition of plants about 10 inches in height was more closely associated with yield than chemical composition when plants were about 30 inches high. Chemical composition of lower stalk or lower leaves was more closely associated with yield than was the composition of other plant parts.     

Use of percentage and milliequivalent expressions in plant composition studies

Abstract

Corn yields and leaf samples vere obtained from experimental plots receiving various rates and combinations of N, P and K. Yields were regressed on leaf N, P, K, Ca and Mg as independent variables expressed in milliequivalents per 100 grams and percentages in three regression models. The fit of two models was shown to be equivalent regardless of method of expressing the independent variables. For the other model the choice of milliequivalents per 100 grams or percentages determines a unique function.     

大豆植株性状相关性与产量回归分析

本文利用3个大豆品种、4种施肥模式条件下,植株产生的17个形态指标及产量差异,进行相关性分析与产量回归分析。结果表明,株高x1、分枝数x5、1粒荚数x9、2粒荚数x10、3粒荚数x11、4粒荚数x12、百粒重x15、经济系数x16等8个大豆植株性状因子对产量有显著性影响;由标准化回归系数得知,对产量作用的大小顺序为:x11>x12>x9>x10>x16>x15>x1>x5。说明提高大豆产量首先要考虑增加有效荚数,其次是提高经济系数,而增加百粒重和株高对于增产的效应较小。育种上需加强生物量大、3粒荚和4粒荚数多、结荚节位低的性状选择;栽培上需注重促进生物量生长、降低结荚节位的促控措施。     

不同缓释有机复肥对夏玉米产量及氮素利用效率的影响

采用田间小区试验,研究了不同缓释有机复肥对夏玉米产量和氮素利用效率的影响。结果表明,以污泥滤饼(沼渣)为主要有机原料生产的胶结型、胶结-包膜型和混合型(30%胶结型缓释肥+70%胶结-包膜型缓释肥)有机复肥较等氮等磷等钾养分用量的常规施肥(化肥+有机肥)分别增加夏玉米产量7.9%、14.9%和20.1%,分别提高氮素利用率8.5、18.0和25.3个百分点,分别提高氮素农学效率0.71、1.33和1.77倍。本试验条件下,混合型缓释有机复肥能保证养分释放动态与夏玉米需肥规律基本吻合,因而增产效果最好,并显著提高了氮素利用效率。     

不同深松时间与深度条件下土壤物理性状与玉米产量的相关分析

通过对土壤含水量、土壤容重、土壤硬度、产量及农艺性状的测定和分析,研究了不同深松时间、深松效果下土壤物理性状和玉米产量的变化并进行相关分析。试验结果表明:经过春季深松40 cm的玉米产量最高,为9 442.5 kg/hm2,比对照增产18.84%,行粒数和百粒重以春季深松40 cm处理的最大。产量与苗期土壤含水量存在极显著正相关,与土壤容重和土壤硬度存在极显著负相关。玉米生育期间对照土壤含水量低于不同处理,春季深松40 cm和深松30 cm处理的土壤含水量高于其他处理。     

Yield and chemical composition of corn grown with subsurfacely injected textile mill sludge

Abstract

The objective of this study was to determine the effects of subsurfacely injected sludge on growth and composition of corn (Zea mays L.) silage. Sewage sludge from a textile mill which produces sanitary products was collected in lagoons and injected into bands 30 cm deep in a well‐drained loam in western Massachusetts. Injection rates were 0, 6.8, 13.6, and 25.6 metric tons of dry material per hectare. The sludge was 3% solids and contained 10 ppm each of Cd, Ni and Pb, 5 ppm of Hg, 70 ppm of Cr, 80 ppm of Zn, and 160 ppm of Cu. Inorganic and organic N composed 0.52% and 5.80%, respectively, while P and K were 0.89% and 0.52%, respectively, of the dry weight of the sludge. Seedling emergence was not hindered, and silage yields were increased by sludge application. No trace element increased in plant tissue with sludge fertilization. Nitrate concentrations increased in the plants with sludge fertilization but only in the roots and stems.     

数字图像和逐步回归客观评定冷却猪肉肉色

为开发准确、快速的猪肉肉色质量客观评定方法,研究了数字图像处理和和逐步回归模型对冷却猪肉肉色客观评定分级的效果.对宰后冷却24 h的猪删体,切开第3～4肋骨间背最长肌,发色60 min,数码相机获取数字图像处理后提取断面肉色参数(L *、a *、b *、Chroma、Hue angle).提取的80头猪胴体背最长肌肉色参数经逐步回归建立了肉色评定模型.结果表明,数字图像处理后提取肉色参数建立的逐步回归模型评定冷却猪肉肉色分值的效果优于BP人工神经网络模型;若以|评定肉色分值-感官肉色分值|≤0.3为评定正确判断标准,前者评定正确率为78.8%,后者为60.4%; 前者与本试验评定正确率最高的单个感官评定人员相比(78.2%),差异不显著(P>0.05).因此,数字图像处理可有效地对冷却猪肉肉色进行客观评定.     

不同化感潜力水稻化感效应与产量的关系

本研究探讨了连续3年5种不同化感潜力水稻田间抑草效应、产量及其之间相互关系。结果表明,不同种植时间,不同化感潜力水稻田间种植过程中伴生杂草总生物量以非化感水稻"Lemont"最大,化感水稻"PI-1"最小。化感潜力分析结果表明,不同化感潜力水稻以化感水稻"PI-1"化感抑草潜力最强,非化感水稻"Lemont"最弱。水稻产量分析结果表明,不除草条件下,不同种植时间均以化感水稻"PI-1"产量最高,非化感水稻"Lemont"产量最低。除草条件下,依然以化感水稻"PI-1"产量最高,化感水稻"IAC47"产量最小。杂草生物量、水稻化感潜力与水稻产量的相关性分析结果表明,不同化感潜力水稻产量的大小与田间杂草生物量存在极显著负相关,与化感潜力大小存在极显著正相关。     

Correlation of petiole sap nitrate-nitrogen concentration measured by ion selective electrode,leaf tissue nitrogen concentration,and tomato yield in Florida

The effectiveness of measuring petiole sap nitrate-nitrogen concentration (PSNC) using ion selective electrode (ISE) has been scrutinized due to claims that PSNC poorly predicts leaf tissue nitrogen concentration (LTNC) or crop yield. This study evaluated the relationship among PSNC, LTNC, and marketable yield of tomato (Solanum lycopersicum L.). Two tomato trials were conducted using seepage irrigation and controlled-release fertilizer (CRF) in fall 2011 and 2012. At 15 days intervals, six most recently mature leaves were collected to measure PSNC and LTNC. PSNC and LTNC declined throughout the growing seasons, but PSNC was affected by weather. PSNC and LTNC were correlated (P = 0.0001, r = 0.38), though not meaningfully. PSNC and LTNC correlated negatively and positively with crop yield in most correlations, respectively. Correlations of CRFs and soluble fertilizers (SFs) separately, did not improve relationships. Measuring LTNC may be a more reliable nutrient management tool compared to PSNC measured using an ISE.     

不同施肥处理对玉米产量及土壤酶活性的影响

分析了不同施肥处理对玉米产量和土壤养分的影响,以及不同生育期内土壤纤维素酶、脲酶和过氧化氢酶的动态变化。结果表明,5个不同施肥处理产量均高于CK;秸秆配施无机肥加秸秆腐熟剂(FS)处理和有机肥配施70% NPK(OF)处理的效果最佳,有机无机复合肥(OI2)、有机无机复合肥(OI1)和常规无机肥(CF)处理次之,不施肥处理(CK)最低。FS处理较常规施肥处理提高了4.87%,有机肥配施70%常规无机肥(OF)处理较常规施肥处理的产量提高了3.39%。施肥处理均能提高3种酶的活性,并且表现出较强规律性:土壤过氧化氢酶在玉米拔节期出现活性高峰,土壤纤维素酶和土壤脲酶在玉米大喇叭口期出现活性高峰;FS处理在各个时期的酶活性较高。综上所述,秸秆还田配施化肥加秸秆腐熟剂有利于增加土壤酶活性与土壤养分含量,提高作物产量。     

Effect of Mg And Zn fertilization on soil test levels,ear leaf composition,and yields of corn in northern West Virginia

Abstract

A corn fertility study was conducted at two locations in northern West Virginia to determine the response of corn (Zea mays L.) to applied Mg and Zn on two soils testing low in Mg by the ammonium acetate and Baker tests and low in Zn by the Baker test. The study consisted of three rates of Mg (0, 112, and 224 kg/ha) and three rates of Zn (0, 3.36, and 6.72 kg/ha) applied in a factorial design. The soil at the Morgantown location was medium textured with a CEC of 22.4, and the soil at the Reedsville location was coarse textured with a CEC of 15.8. Yield responses to applied Mg were obtained only on the coarse textured soil at the Reedsville location where exchangeable Mg was less than 5% of the CEC and equilibrium Mg was less than 9.0 10 ^‐4M. No yield response to Zn was obtained at either location.     

不同玉米果穗位姿与含水率对穗柄断裂特性的影响

为解决现有摘穗机构功耗大、苞叶残留多的问题,该文以手工摘穗为研究模本,提炼出基于果穗位姿变化的穗柄受力断裂模型。以4种不同含水率的收获期玉米为试验材料,以果穗偏转角度为因素,进行了2组穗柄拉伸断裂随机区组试验。结果表明,随着果穗偏转角度增大,穗柄拉断力、断裂拉伸量及苞叶残留率会在一临界角度产生突变;当籽粒含水率分别为34.8%、30.2%、25.1%和20.3%时,该临界角度分别为50°～55°、50°～55°、45°～50°和45°～50°;穗柄偏转达到临界角度后,玉米穗柄拉断力分别降低了80%、86%、84%和80%,断裂拉伸量增加了72%、70%、93%和84%,苞叶去除率增加了41%、34%、32%和36%;结果表明,对茎秆施加拉力时对果穗施加横向载荷,使果穗发生大于临界角度的偏转,可实现低耗摘穗;分析发现,穗柄断裂行为突变的诱因是表层纤维的受力由拉应力变为弯曲正应力,导致裂纹的萌生和扩展机理发生变化。该研究可为新型摘穗机构的设计提供理论依据和数据支撑。     

不同覆盖材料土壤生态效应与玉米增产效应研究

田间试验研究不同覆盖材料土壤生态效应与玉米增产效应结果表明,小麦秸秆、地膜、高粱秆片和纸板覆盖均有显著保水作用及明显水分表聚现象,即0～10cm表层土壤含水量明显高于下层土壤,地膜覆盖兼有显著增温效应,而小麦秸秆、高粱秆片和纸板覆盖土壤温度却明显低于对照。除纸板外其他覆盖材料均不同程度增加0～2 0cm土层土壤细菌、真菌和放线菌数量,且以秸秆覆盖增幅最大。各覆盖处理均显著增加玉米株高、茎粗和叶面积指数,不同程度提高玉米生育前期倒1、2、3叶净光合速率。小麦秸秆、地膜、高粱秆片、纸板覆盖处理分别比对照增产19.4 %、17.2 %、16 .1%和13.3% ,其增产原因主要是由于穗长和穗粒数的增加所致     

生物柴油冷滤点与其化学组成的定量关系

生物柴油的低温流动性主要取决于化学组成。为了量化表征生物柴油组成与其冷滤点的关系,采用气相色谱-质谱与冷滤点分析技术和多元线性回归分析方法,分析了生物柴油的脂肪酸甲酯组成和冷滤点,研究了脂肪酸甲酯组成对冷滤点的影响规律。研究表明：生物柴油主要由14～24个偶数碳原子组成的长链脂肪酸甲酯组成,其中饱和脂肪酸甲酯主要为C14:0～C24:0,不饱和脂肪酸甲酯主要为C16:1～C22:1、C18:2～C20:2和C18:3。120种生物柴油油样中,乌桕梓油生物柴油的冷滤点最低,为-14℃,花生油生物柴油的冷滤点最高,为13℃。生物柴油的脂肪酸甲酯的含量与分布不同,冷滤点差异较大。冷滤点随饱和脂肪酸甲酯含量的增加呈线性升高,且碳链长的较短的增加显著;随不饱和脂肪酸甲酯含量的增加而呈线性降低,且不饱和度高的较低的降低略明显。建立了线性相关性非常显著（R=0.971）的基于组成的冷滤点预测模型。研究结果为不同环境下生物柴油的推广应用提供参考。     

Relationship between nutrient element content of the index leaf and cane yield and juice quality of sugarcane genotypes

Abstract

The nitrogen (N), phosphorus (P), potassium (K), iron (Fe), manganese (Mn), zinc (Zn), and copper (Cu) content of the index leaf (whole third leaf) of eleven genotypes of sugarcane [Co 7717, CoJ 64, CoP 84211, CoH 92, and CoH 99 (early maturing); CoS 767, CoH 3, and CoH 108 (mid maturing); and Co 1148, CoH 35, and CoLK 8102 (late maturing)] were determined at the maximum growth stage of the crop. The elemental contents were correlated with cane yield and juice quality parameters [% sucrose, % commercial cane sugar (CCS), and sugar yield] at harvest. The N, P, K, Fe, Mn, Zn, and Cu contents of the third whole leaf for all eleven genotypes ranged (mean in parenthesis) from 1.46–1.80 (1.62), 0.20–0.37(0.30), 1.39–1.88 (1.67)%, and 376–1095 (613), 58–155 (98), 53–99 (74), and 8–14 (11.5) ugg¹ of dry weight, respectively. Among the eleven genotypes, CoJ 64 had lowest N, P, and K contents in their index leaves as well as the lowest cane yield, % sucrose, and sugar yield, whereas CoH 35 had highest, followed by CoH 108 for these parameters. The leaf N, P, and K contents showed significant linear positive correlations with cane yield (r=0.84, 0.79, and 0.87, respectively), % sucrose (r=0.70, 0.68, and 0.65, respectively), and sugar yield (r=0.89, 0.81 and 0.90, respectively). Among the micronutrients, leaf Cu had a linear positive correlation (r=0.61) with cane yield. The multiple regression of cane yield with N, P, K, Zn, and Cu explained 93% of the variation, whereas the multiple regression of % sucrose and % CCS with N, P, and K leaf content and sugar yield with N, P, K, and Cu explained 82%, 84%, and 95% of the variation, respectively.     

Comparison of multivariate models and variable selection algorithms for rapid analysis of the chemical composition of field crops

This study evaluates the use of visible and near-infrared spectroscopy for rapid prediction of total carbon, total nitrogen, and total phosphorus concentrations in field crop samples. Two multivariate models (partial least squares regression and support vector machine regression) were compared. In addition, four spectral variable selection algorithms (competitive adaptive reweighted sampling, genetic algorithm, uninformative variable elimination, and variable importance for projection) were applied with support vector machine regression to determine the most accurate predictions. The results showed that support vector machine regression performed better than partial least squares regression for predicting the three chemical compositions. The combination of competitive adaptive reweighted sampling and support vector machine regression outperformed the other models for the predictions of total carbon and total nitrogen with high coefficients of determination of 0.91 and 0.90, respectively. For the determination of total phosphorus, the prediction accuracy of competitive adaptive reweighted sampling was comparable with the best result obtained from genetic algorithm with the coefficients of determination of 0.73 and 0.77, respectively. In conclusion, the support vector machine regression combined with competitive adaptive reweighted sampling has great potential to accurately determine the chemical composition of field crops using the visible and near-infrared spectroscopy.     

Effect of magnesium fertilization on yield and leaf composition of tomato plants

Tomato plants were grown for 2 years at 4 different rates of Mg fertilization on a Princeton loamy sand at pH 4.8 with 29 kg exchangeable Mg/ha. Calcareous limestone was used to provide a pH treatment in the second year. Magnesium deficiency symptoms were observed on plants grown on plots having ≤ 38 kg/ha NH₄OAC‐extractable Mg. Application of 56 kg Mg/ha corrected Mg deficiency and produced a significant increase in yield. Application of calcitic limestone also produced significant yield increases, but did not affect the development of Mg deficiency symptoms. Tomato yield was increased 27.9% by Mg application and 17.7% by lime application. Highest tomato yield was obtained with application of 112 kg Mg/ha. Symptoms of Mg deficiency were observed when the Mg concentration in recently mature leaf tissue was in the 0.30 to 0.32% range. Magnesium concentration in leaf tissue increased linearly with increasing Mg rate. Leaf Mg concentration at various growth stages of the tomato plant was variable depending on Mg treatment. Magnesium fertilization rate bad little effect on Ca or K leaf concentrations. Application of Calcltic limestone increased leaf tissue Ca and reduced leaf tissue Mg and Mn concentrations.