摘要:

Tomato plants (Lycopersicon estulentum) ‘Ife plum’ were grown in soil culture and treated with B concentrations of 0‐, 2‐ and 4‐ppm. Boron deficiency symptoms were observed at the 0 ppm treatment, while a normal and healthy growth of the plants was observed for the 2 ppm B treatment. The 4 ppm B treatment resulted in severe leaf necrosis and numerous necrotic patches at the nodes, internodes and the peduncles.

ISSN:0010-3624    

DOI:10.1080/00103627809366783

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

A total of seventy‐three U.S. corn (Zea maysL.) inbreds and hybrids were grown in the greenhouse for two to four weeks in low and high available P nutrient solutions and soils to select for phosphorus efficiency based on yield differences in a low available P medium. Variation in growth in the low P medium was partially explained by differences in early growth vigor (especially when inbreds and hybrids were compared in the same trial) but not by any apparent differences in P absorption characteristics. Seventeen hybrids with high yields in the adequate P medium and contrasting yields in the low P cultures were grown to maturity in a very low available P (5 ppm Bray 1) Berks soil (a Typic Dystrochrept) in the field with and without added fertilizer P but with other nutrients and lime adequately supplied to both treatments. The relative growth rate of these hybrids in a low P medium in the greenhouse was not correlated with their yield in the low available P soils in the field. This may be due to the relatively small differences in yield in the low P soil in the field and the strong influence of seedling vigor on early growth in the greenhouse. Based on this study, screening corn for P efficiency in the field is much more likely to succeed than are short term greenhouse screenings.

ISSN:0010-3624    

DOI:10.1080/00103627809366784

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

An inexpensive steam generator and distillation head for nicrokjeldahl determinations is described. The generator consists of a soil moisture pressure plate extractor with heating coils and a water level control chamber. A distillation head and vacuum system is also described which allows for vacuum removal of waste from the tubes after distillation and rinsing of the distillation head between runs.

ISSN:0010-3624    

DOI:10.1080/00103627809366785

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

Pruning was more effective than N fertilization in increasing the N concentration in leaves of dry‐farmed mature almond trees.

ISSN:0010-3624    

DOI:10.1080/00103627809366786

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

Field and growth chamber studies comparing polyphosphate and orthophosphate fertilizers were conducted with soils of pH 7.2 ‐8.0. Applied P frequently increased grain yields in the field and plant dry matter production in the growth chamber along with P concentrations in the plants. Yield differences between poly‐ and orthophosphate P carriers were not significant. In one growth chamber study, ammonium polyphosphate (APP) produced significantly higher zinc concentrations in corn (Zea maysL.) than did ammonium orthophosphate (AOP) applications. In one field study, APP also produced significantly higher P concentration in grain sorghum (Sorghum bicolor) leaves than did AOP and potassium polyphosphate (KPP). Soil Zn applications usually increased plant Zn concentrations in the field and growth chamber.

ISSN:0010-3624    

DOI:10.1080/00103627809366787

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

Magnesium and Ca concentrations in smooth bromegrass (Bromus inermisL) were not affected by late‐winter applications of N. Magnesium concentrations were constant until rapid growth in mid‐May then they declined until early June harvest. Highest seasonal concentrations were found in the fall regrowth. Calcium concentrations declined as plants matured in spring. Highest seasonal Ca concentrations were found in the fall regrowth. Nitrogen, P, and K concentrations and K/(Ca+Mg) ratios were increased by N applications during early spring but did not differ significantly by early June harvest. Nitrogen and P concentrations decreased as plants matured in spring and fall. K concentrations and K/(Ca+Mg) ratios changed inconsistently from sampling date to sampling date. Forage yields were approximately doubled by 67 kg N/ha and tripled by 202 kg N/ha. Significant yield differences were related to different N carriers.

ISSN:0010-3624    

DOI:10.1080/00103627809366788

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

A study was conducted to determine differences among soil testing laboratories in soil sampling and testing procedures and in fertilizer recommendations for turfgrass maintenance and establishment. Seven soil samples and a questionnaire concerning procedures and recommendations were sent to seven laboratories. Laboratories differed in recommended sampling depths; extracting solutions; ranges for nutrient levels in high, medium, and low categories; and in recommendations for various species and varieties. For laboratories using the same extractants, pH and nutrient levels were similar; however, considerable differences occurred in limestone and fertilizer recommendations based on the laboratory results.

ISSN:0010-3624    

DOI:10.1080/00103627809366789

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

The effects of sampling depth and thatch on soil test results of turfgrass areas were studied. Several turfgrass areas with known fertility and management histories were sampled in 3.8 or 5.0 cm increments to depths of 10 or 15 cm. Sampling depth significantly affected the levels of P, K, Mg, Ca, and pH in one or more of the areas sampled. The direction and magnitude of change was dependent on such factors as previous rates of fertilization, soil texture, and various management practices. Although soil fertility values changed with depth, changes in fertilizer recommendations due to sampling depth were minimal. Sampling depth data also gave an indication of greater nutrient removal in the surface 4 to 5 cm of soil than at lower depths. The inclusion of thatch with the soil sample increased soil test levels of K and CEC, decreased pH, and did not affect P levels.

ISSN:0010-3624    

DOI:10.1080/00103627809366790

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

ISSN:0010-3624    

DOI:10.1080/00103627809366782

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor