Winter Annual Rye Seeding Date Influence on Nitrogen Recovery and Ammonia Volatilization from Late Fall Surface-Applied Manure
, Masoud Hashemi 1,*, Allen Barker 1, Omid Reza Zandvakili 1 and Zohreh Emami Bistgani 2Round 1
Reviewer 1 Report
Please see the attached document for specific comments and suggestions.
Comments for author File: 
Comments.pdf
Author Response
Reviewer 1 corrections
L 26:
The highest rates of ammonia volatilization were detected in the first 24 hours after manure spreading regardless of the treatment
L 28:
The result indicated that cover crop use significantly limited volatilization compared with no cover crop.
L 29:
Space added
L 32:
Forage rape yielded more biomass when planted after all cover crop treatments with manure application
L 33:
Prior to forage planting, the nitrate-N content in all three soil depths (0-20, 20-40, 40-60 cm) in the plots with manure was higher than plots with no manure.
L 48:
Organic (C) replaced with Organic carbon
L 52:
N replaced with nitrogen
L 56:
Citation added #8
L 58:
Started a new paragraph
L 63:
The amount of N loss due to NH3 volatilization following manure application to the agricultural land depends on many factors such as type and characteristics of the manure, the timing, amount and method of application, and local climatic and soil conditions
L 73:
When manure is applied and incorporated into bare soils to avoid ammonia volatilization, the nitrogen released from manure can be lost through leaching
L 109:
When we converted the figure from the word to pdf, we did not get any problem. We check again with the journal about their pdf convertor
L 121:
“Plots, in spring, were disked which left approximately 30% of the overwintered residue cover on the soil surface”.
It was not that we aimed 30% cover, but rather an estimate of residues left after spring disking
L 135:
NH4-N subscripted
L 162:
Dried samples were weighed for dry matter and then ground using a heavy-duty grinder.
L 171:
The explanation is that: to have more estimated result, we collected soil samples two times, once before manure application to determine soil nitrate in early December and the next time just prior to planting forage rape in April.
Reviewer 2 Report
Please check out my comments file attached.
Comments for author File: Comments.pdf
Author Response
Reviewer 2 corrections
L 187:
In our test of the null hypothesis, we used 0.05 as the critical significance level and the result revealed that there is statistically significant difference among the cover crop dates of planting with mid-Sep resulted the lowest amount of ammonia volatilization. On the contrary, the lowest amount of volatilization occurred with the treatment of no cover crop indicative of the fact that cover crop management to produce biomass plays a significant rule in reducing ammonia volatilization when manure is applied in agricultural soils.
L 201:
We are justifying our result as compared with existing literatures that planted cover crops in earlier dates as compared with our experiment. We carefully collected weather data hourly in our study during measuring ammonia volatilization period, however since manure applied to all treatments regardless of cover crop planting dates, we avoided to further draw our result based on the correlation between air temperature and ammonia volatilization. We would provide the raw data, in case it is necessary.
A previous experiment conducted by Sadeghpour et al at the same experiment site (Ref# 6) revealed that ammonia volatilization followed quadratic trends after manure applied to the field plots. The authors argued that theoretically linear and/or quadratic models are better choice for this type of experiment (in our case quadratic) involving manure application. Specifically those measurements are conducted with a lag (no sampling during nighttime) and therefore not equivalent to exponential growth or decay models. Moreover deploying an exponential model is indicative of a quick rise or a quick fall in one direction. Our choice of quadratic reveals that eventually volatilization will cease after a period of increase, depending on the amount of manure, weather conditions, and other factors. Other published data also indicated that ammonia volatilization theoretically (in case measured in short period) and in practice (long term experiments) followed a quadratic trend.
Soil physical and chemical characteristics:
The soil type was a Hadley fine sandy loam (coarse-silty, mixed, superactive, nonacid, mesic Typic Udifluvent) and the selected soil physical and chemical characteristics of the top 15 cm were as follows: 31% clay, 56% sand; ECEC 3 to 4 cmolc kg-1, pH 5.7 (l:l, soil: water), organic matter content of 1.1%, extractable N, P, K, and Ca content of 3, 8, 71, and 855 mg kg–1, respectively.
Figure 4:
For footnote: Letters note separation of means by Duncan’s New Multiple Range Test, P=0.05.
The explanation that how we measured soil nitrate and the way we used illustration by providing graphs, follows the previous manuscript conducted on manure volatilization published in Journal of Communications in Soil Science and Plant Analysis (Ref # 34). Additionally, if we replace the average of the soil layer, it would create some sort of false reflection and feedback for the readers, which may possibly cause misunderstanding the real measurement of soil depth.
L 109:
When we converted the figure from the word to pdf, we did not get any problem. We again check with the journal about their pdf convertor
L 114:
Added Scientific name: “The main plots consisted of three bi-weekly winter annual rye (Secale cereale L.) planting dates beginning in mid-September along with a no-cover crop treatment as control”
L 122:
Added Scientific name: “Forage rape (Brassica napus L.) was planted at 5.5 kg ha-1 pure live seed in late April and harvested in early August”
L 40:
Keywords sorted by alphabetical order “ammonia volatilization; forage rape; soil nitrogen; winter rye”
L 135:
Ordered as the table “Dry-matter (DM), total NH4-N, total N (TN) and Ph”
L 122:
(Table 2) at the end of the sentence deleted
L 230:
132.00 in the table replaced with 132
L 251:
(Figure 4) at the end of the sentence deleted
L 282:
Furthermore, manure application in late fall produced less nitrate leaching than an early fall application and produced amounts of leaching equal to that of spring applications of manure.
L 298:
figure 5 replaced by Figure 5
L 304:
(Figure 5) at the end of the sentence deleted
L 317:
Space added (P= 0.05).
L 321:
The sentence deleted: “Dairy farmers in the Northeast face challenges for application of manure in fall and on-time planting of cool-season grasses to maximize recovery of residual N and nutrients released from fall applied manure.”
Round 2
Reviewer 1 Report
You mention two different soil classifications. Please correct.
Line 94-95: "-1" needs to be superscript.
Line 170: volatilization "were" detected
Line 245: is this within depth? You must make this CLEAR
Lines 250 and 261: Exact same paragraphs.
Line 221: 2.3 instead of 3.3
Line 268: 2.4 instead of 3.4
