ALBERT — All Library Books, journals and Electronic Records Telegrafenberg

1

Electronic Resource

Phenological Temperature Response of Maize (1998)

Stewart, Douglas W. ; Dwyer, Lianne M. ; Carrigan, Lori L.

Springer

Agronomy journal 90 (1998), S. 73-79

add to mindlist on the mindlist

Details

ISSN: 1435-0645

Source: Springer Online Journal Archives 1860-2000

Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition

Notes: 30,10 ) limits predictability of maturity in hybrid maize (Zea mays L.). Data sets of daily maximum and minimum air temperatures and dates of maize development stages were collected for a range of hybrids in Canada and the northern USA (39° to 45°N lat). Data were analyzed to improve the temperature response functions for maize at different stages of development. Results indicate that during vegetative growth, phenological response to mean daily air temperature followed a sigmoidal curve beginning below 5°C, with maximum response to temperatures between 25 and 30°C. During reproductive growth, the temperature response function was flat from 0 to 12°C and rose significantly only with mean daily air temperatures greater than this range. A general thermal index (GTI) based on these two response functions improved estimation of maturity dates by 50% over estimates made using GDD30,10 (SE of 6.7 d for GTI and 13.6 d for GDD30,10 in estimating time from planting to maturity). The greatest improvement using GTI occurred for the reproductive period (SE of 5.8 d using GTI, compared with 12.1 d using GDD30,10). These results suggest that incorporating the temperature response function reported in this paper would improve prediction of maize development.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/

Permalink

	Location	Call Number	Expected	Availability

Others were also interested in ...

Paper (German National Licenses)

Fulltext

2

Electronic Resource

A Sampling Method for Measurement of Large Root Systems with Scanner-Based Image Analysis (2000)

Costa, Carlos ; Dwyer, Lianne M. ; Hamilton, Robert I. ; [et al.]

Springer

Semigroup forum 92 (2000), S. 621-627

add to mindlist on the mindlist

Details

ISSN: 1432-2137

Source: Springer Online Journal Archives 1860-2000

Topics: Mathematics

Notes: Zea mays L.) genotypes with contrasting root morphologies: leafy reduced stature (LRS), leafy normal stature (LNS), and Pioneer 3905 (P3905), a commercial hybrid. Root length was determined for 957 subsamples. Confidence intervals were generated by software using the bootstrap resampling approach for optimizing sample size. Confidence intervals for mean estimates of each sample size were defined by ordering the evaluation function values from the smallest to the largest in a set of 5000 iterations. The lower and upper bounds of confidence intervals were also calculated using the standard procedure. This system allowed collection of homogeneous subsamples. Calculations showed that ∼10% of total root volume should be analyzed for estimation of the entire root system to be accurate within 10%. Although unreplicated, these data suggest that maize genotypes with the leafy trait have greater root lengths (1.75 km for LRS, 2.37 km for LNS, and 0.49 km for conventional commercial hybrid P3905) and a greater proportion of fine roots than the nonleafy type.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/

Permalink

	Location	Call Number	Expected	Availability

Others were also interested in ...

Paper (German National Licenses)

Fulltext

3

Electronic Resource

Soil Nitrogen Amendment Effects on Nitrogen Uptake and Grain Yield of Maize (1999)

Ma, B. L. ; Dwyer, Lianne M. ; Gregorich, Edward G.

Springer

Semigroup forum 91 (1999), S. 650-656

add to mindlist on the mindlist

Details

ISSN: 1432-2137

Source: Springer Online Journal Archives 1860-2000

Topics: Mathematics

Notes: Zea mays L.) production is necessary to maximize producer's economic returns and to maintain soil and water quality. A 5-year field experiment was conducted on a Brandon loam soil (fine loamy, mixed, mesic Typic Endoaquoll) (Orthic Humic Gleysol) with the objective of measuring N uptake and grain yield of two maize hybrids under different N amendments [no amendment, NH4NO3 at 100 and 200 kg N ha-1 (wet wt.)] to determine differences in N use efficiency (NUE) and its components, N uptake efficiency and N utilization efficiency. The N amendments increased the grain yield (by an average of 20%) and NUE (by an average of 17.5%) of a modern hybrid (Pioneer '3902') more than that of an old hybrid ('Pride 5'). The difference method that was used to estimate N recovery indicated that, over the course of the study, Pioneer 3902 took up 48% of inorganic fertilizer N and 20% of the manure N, compared with 42 and 16%, respectively, for Pride 5. Manure application resulted in total N uptake comparable to the 200 kg N ha-1 treatment. Grain yields of manure treatments in 1993 and 1994 were generally lower (5-15%) than the 200 kg N ha-1 treatment. During the latter periods (1995 and 1996) of the study with repeated application under continuous maize, all manure treatments produced grain yields equal to or slightly greater (6-13%) than the fertilizer treatment. Dairy manure application increased N uptake and grain yield of maize. The NUE, based on added mineral N levels, for all manure treatments was greater than for the 200 kg N ha-1 treatment.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/

Permalink

	Location	Call Number	Expected	Availability

Others were also interested in ...

Paper (German National Licenses)

Fulltext

4

Electronic Resource

Soil Nitrogen Amendment Effects on Seasonal Nitrogen Mineralization and Nitrogen Cycling in Maize Production (1999)

Ma, B.L. ; Dwyer, Lianne M. ; Gregorich, Edward G.

Springer

Agronomy journal 91 (1999), S. 1003-1008

add to mindlist on the mindlist

Details

ISSN: 0002-1962

Source: Springer Online Journal Archives 1860-2000

Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition

Notes: + 4 plus NO− 3) of ≈100 kg N ha−1 and up to 800 kg N ha−1 of total N resulted in up to 120 kg ha−1 of net N mineralized. The potential loss of this mineralized N was minimized during the growing season compared with inorganic fertilizer application because of the synchronization of soil N release and uptake by maize (Zea mays L.). In soil receiving 200 kg inorganic N ha−1, the amount of net N mineralized over the season was between 130 and 170 kg ha−1, but large losses of mineral N from the rooting zone occurred during the same period. The amount of net N mineralized over the season accounted for up to half of the plant N uptake in all treatments; for example, the amount of net N mineralized in manured soils represented about 30 to 60% of total plant N. It appears that a priming effect on soil mineral N occurred in all treatments during the vegetative period. This resulted in a curvilinear relationship between net N mineralization rate and soil mineral N levels at pre-planting that reached a plateau at ≈140 kg N ha−1. The rate of N mineralization during the grain-filling period was approximately the same at both levels of inorganic N fertilizer, but was, on average, three times higher under manure treatments. Compared with N mineralization under the 200 kg N ha−1 fertilizer treatment, all manure treatments resulted in higher rates of net N mineralization during the grain-filling period.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/

Permalink

	Location	Call Number	Expected	Availability

Others were also interested in ...

Paper (German National Licenses)

Fulltext

5

Electronic Resource

Guidelines for Comparisons among Different Maize Maturity Rating Systems (1999)

Dwyer, Lianne M. ; Stewart, Douglas W. ; Carrigan, L. ; [et al.]

Springer

Agronomy journal 91 (1999), S. 946-949

add to mindlist on the mindlist

Details

ISSN: 0002-1962

Source: Springer Online Journal Archives 1860-2000

Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition

Notes: Zea mays L.) maturity in North America, including growing degree days, crop heat units, and Minnesota relative maturity rating days. Correspondence between the different systems varies with the temperature range of the environment, because of different bases of calculation and unit size. However, general guidelines for conversion from one system to another would aid communication among researchers, producers, distributors, and extension personnel, particularly where regional preference for one system exists, but information developed in another region is shared. Simple regression equations were developed from a data set with 4 years, 28 hybrids, and 19 locations (between 39° and 48° N lat). Coefficients of determination were ≥0.91, indicating that these equations could be used as a general guideline to compare maturity ratings developed using the different systems.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/

Permalink

	Location	Call Number	Expected	Availability

Others were also interested in ...

Paper (German National Licenses)

Fulltext

6

Electronic Resource

A General Thermal Index for Maize (1999)

Dwyer, Lianne M. ; Stewart, Douglas W. ; Carrigan, L. ; [et al.]

Springer

Agronomy journal 91 (1999), S. 940-945

add to mindlist on the mindlist

Details

ISSN: 0002-1962

Source: Springer Online Journal Archives 1860-2000

Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition

Notes: Zea mays L.) for maturity. Separate temperature response functions for the vegetative and grain-filling periods predict more accurately time to maturity than a single function for the two periods combined. However, use of two functions requires a priori knowledge of the silking date, which becomes the transition date from the vegetative function to the grain-filling function. The objective of this study was to evaluate the sensitivity of estimates of silking and maturity dates to the transition date between vegetative and grain-filling functions and to develop a protocol to combine the two temperature response functions in a general thermal index (GTI) for maize. Frequency distributions of mean daily air temperatures for five 20-d periods spanning mid-June to late September at 19 locations in the northern USA and southern Ontario from 1992 to 1995 indicated few days (≤12%) with mean daily air temperatures less than 15°C before late August. This was significant, as the two response functions diverged significantly at temperatures below 15°C. Standard errors in estimating maturity date using different transition dates remained small (〈7.5 d) unless the transition date was delayed beyond the first week of September. Based on this analysis, a standard transition date of 1 August was proposed for the GTI. Testing on an independent data set indicated that the GTI and a transition date of 1 August provided more accurate estimates of the planting to maturity period than growing degree days (GDD) or crop heat units (CHU), with a standard error of 8.2 d (compared with 14.5 d using GDD and 12.5 d using CHU).

Type of Medium: Electronic Resource

URL: http://dx.doi.org/

Permalink