Previous Corn Row Effects on Potassium Nutrition and Yield of Subsequent No‐Till Soybeans

Abstract

Narrow‐row soybean [Glycine max (L.) Merr.] production in corn [Zea mays L.]–soybean rotations results in various distances of soybean rows from previous corn rows, yet little is known about soybean responses to proximity to prior corn rows in no‐till systems. The objective of this study was to evaluate the impacts of preceding corn rows on potassium (K) nutrition and yield of subsequent no‐till soybeans. Four field experiments involving a corn–soybean rotation were conducted on long‐term no‐till fields with low to medium K levels from 1998 to 2000 near Paris and Kirkton, Ontario, Canada. In the corn year, treatments included K application rate and placement in conjunction with tillage systems or corn hybrids. Before soybean flowering, soil exchangeable K concentrations (0–20 cm depth) in previous corn rows were significantly higher than those between corn rows. At the initial flowering stage, trifoliate leaf K concentrations of soybeans in preceding corn rows were 2.0 to 5.3 g kg^?1 higher than those from corresponding plants between corn rows. Yield of no‐till soybeans in previous corn rows increased 10 to 44% compared to those between previous corn rows. Positive impacts of prior corn rows on soil K fertility, soybean leaf K, and soybean yield occurred even when K fertilizer was not applied in the prior corn season. Deep banding of K fertilizer tended to accentuate row vs. between‐row effects on soybean leaf K concentrations in low‐testing soils. Corn row effects on soybeans were generally not affected by either tillage system or corn hybrid employed in the prior corn crop. Potassium management strategies for narrow‐row no‐till soybeans should take the potential preceding corn row impacts on soil K distribution into account; adjustments to current soil sampling protocols may be warranted when narrow‐row no‐till soybeans follow corn on soils with low to medium levels of exchangeable K.     

The effect of potassium fertilization on iron deficiency

Abstract

Preliminary experiments indicate that potassium fertilization at a rate of 270 mg K/kg soil amel.iorates Iron deficiencies in peanuts grown in an extremely calcareous soil (63% CaCO₃). Amelioration was greater with the application of KCl than with that of KNO₃ or K₂HPO₄, indicating that the cation:anion balance of roct uptake is involved. Potassium chloride application caused a 73% increase in the chlorophyll content; this value is 90% of that of the FeEDDHA treatment. Manipulation of the cation: anion balance of macronutrients may prove to be an effective means of controlling lime‐induced chlorosis.     

5种药剂的不同质量浓度处理对小麦陈种子发芽及田间成苗的影响

以保存4 a的青春38小麦种子为供试材料，用不同质量浓度聚乙二醇、青霉素、甲基托布津、高锰酸钾、双氧水进行浸种处理。结果表明，以200 mg/L聚乙二醇、200 mg/L青霉素、1.5 g/L甲基托布津、10 g/L高锰酸钾及双氧水浸泡10 min处理种子，其发芽率、幼苗根系活力、叶片叶绿素含量和田间成苗效果最好，与CK差异达到显著水平（P<0.05）。说明一定质量浓度和时间的药剂浸种处理促进小麦陈种子新陈代谢系统的修复和恢复,充分利用胚中贮存的营养物质,使幼苗达到与正常常规种子生长的指标，建议在农业生产实践中应用。     

施用钾肥对烟草铅量吸收的影响

采用温室大棚盆栽模拟实验，研究了红壤土受铅污染后，施用不同浓度的K2SO4肥对烟草的生长发育和对铅吸收的影响及铅在植株体的分布状况。通过测定烟株不同部位的铅含量来分析施用硫酸钾肥对烟草铅吸收的影响，结果表明，在试验范围内随着钾肥施用量的增加，烟株的生长得到促进的同时烟草铅含量逐渐降低，说明施用硫酸钾肥降低了铅对植物的有效性。从K2SO4肥的施用水平对降低铅的植物有效性分析表明，硫酸钾肥对降低铅在植株体内的富集系数是由K＋和陪伴阴离子（SO4^2-）共同作用的结果。     

有机肥原料中有机质含量的简易测定

[目的]用简易方法测定有机肥原料中的有机质含量。[方法]以不同火力煅烧样品,将减重率作为样品的有机质含量,并与重铬酸钾氧化法相对照。[结果]木薯渣以中高火煅烧8 min,毛发渣以中高火煅烧5 min,腐殖土分别以中高火煅烧3 min和5 min并取其均值,豆腐渣分别以中火煅烧3 min和8 min并取其均值,所得减重率与重铬酸钾氧化法测得的有机质含量基本吻合。[结论]不同原料采用不同的煅烧条件,并乘以适当的校正系数,可较为准确地测定有机肥原料中的有机质含量。     

钾对玉米正常生长发育及其生理机能的影响

钾是玉米生长发育所必需的三大营养元素之一,土壤缺钾,直接妨碍玉米根系和茎叶的正常发育,影响对水分和养分的吸收及光合产物的合成和运输,使玉米抗病、抗旱、抗寒、抗倒伏等各项生理机能降低,影响玉米产量和品质的提高。     

转大豆DNA玉米的氮钾含量测定

以发育正常的诱变玉米(26DC),对照材料(26CK)为试验材料研究了玉米穗位叶和籽粒在不同生育期的氮钾含量。结果表明,转大豆DNA玉米的氮含量、钾含量均与转化前有显著差异,同等施肥条件下,DC乳熟期籽粒中氮含量高于CK 19.7%,DC穗位叶的钾含量在前四期平均高于CK 19.4%,DC籽粒腊熟期钾含量高于CK同期50%,对氮素的代谢有良好的促进作用。     

Targeted metabolomics study of ‘Braeburn’ apples during long-term storage

‘Braeburn’ is an apple cultivar susceptible to the occurrence of internal browning (Braeburn Browning Disorder; BBD) during storage. This physiological disorder is characterized by the development of brown spots inside the fruit, eventually resulting in the formation of cavities. The objective of this study was to investigate the effects of the preharvest application of calcium, potassium and triazole fungicides on the postharvest primary metabolites of ‘Braeburn’ fruit, and to offer a better understanding of the biochemical processes behind internal browning. The primary metabolites of ‘Braeburn’ fruit cortex samples at harvest and after 2 weeks, 4 weeks, 4 months and 8 months of storage at browning-inducing conditions were analyzed using GC–MS. No significant difference in the primary metabolites was observed between the different levels of the applied preharvest applications. Early during storage, fruit developed browning, with the severity increasing with storage duration. This was correlated with a group of primary metabolites that showed either an increase (e.g., alanine, galactose, mannitol, sorbitol, xylose) or a decrease (e.g., malate, sucrose) in concentration with time. Radial distribution of the metabolites in the fruit tissue was also observed; some metabolites (e.g., galactose, mannitol) were higher in concentration in the inner cortex, while the concentrations of other metabolites (e.g., mannose, sucrose) were higher in the outer cortex.     

Evaluation of differences in potassium availability in soils of the same exchangeable potassium level

Abstract

Potassium availability was determined by growing corn (Zea mays L.) in pots of soil in a controlled environment chamber. Comparison of K uptake rate per unit root area indicated differing degrees of K availability. The differences in availability among soils were not predicted by differences in cation exchange capacities. The K concentration in solution and the average rate of diffusion more nearly reflected differences in K availability, particularly when the kinetic rate factors of diffusion and mass flow were integrated with root growth and uptake factors in the Cushman mathematical model of K uptake. Utilization of this model demonstrated the importance of using rate factors for ion movement in soil along with plant factors of root growth in predicting K availability.     

Responses of the First Internodes of Hong Mang Mai Wheat to Ethylene,Gibberellins and Potassium

Abstract

Seedlings of Hong Mang Mai wheat ( Triticum aestivum L.) emerge from much deeper in the soil than do other cultivars by elongating their first internode. We examined the roles of ethylene, gibberellins (GA) and potassium in the elongation of the first internode in wheat cultivars. Although ethylene stimulated the elongation of the first internode of Hong Mang Mai in the dark, the ethylene evolution and the expression level of ethylene-receptor-like gene of this cultivar were not greater than those of other cultivars.

In Hong Mang Mai, gibberellin A₃ (GA₃) substantially stimulated the elongation of the first internode in the dark. Maximum elongation of the first internode was obtained by GA₃ at the concentrations of 2.89 × 10^–6 to 2.89 × 10^–7 M. This cultivar responded markedly to gibberellins A₁ and A₃ by elongating the first internode in the dark. A mixture of gibberellins A₄ and A₇ (GA₄₊₇) was not effective in inducing the elongation. Haruhikari, a cultivar having no GA -insensitive-reducing-height (Rht) genes, substantially responded to GA₃, but other cultivars did not. The differences in the sensitivity to GA could account, at least in part, for the varietal differences in the elongation of the first internode in wheat. Takune-komugi, a cultivar whose first internode elongates in response to ethylene, did not respond to GA₃. Thus, there are different mechanisms for the GA- and ethylene-stimulated elongation of the first internode in wheat.

Also, it was suggested that potassium uptake from the soil might function together with endogenous GA in inducing the elongation of the first internode in Hong Mang Mai wheat.