How much fertilizer do farmers lose when they apply nitrogen in season? Is volatilization a significant problem? Could 4R nutrient management and urease inhibitors help? To answer those questions, our research team had an interview with RealAgriculture in Canada. ArticleCorn School: How much nitrogen is lost when applying in season?
After 18 – 20 days from R1 stage, the kernels become mostly yellow and contain “milky” white fluid (i.e. starch accumulates). However, moisture content of kernel at R3 is around 80%. Starch accumulation continuously occurs in the endosperm, and cell division of endosperm is almost complete, indicating that growth of kernels since R3 would be mostly due to cell expansion and starch accumulation rather than cell division of endosperm. It also means that potential kernel size would be finally determined…
Here is an example of missing data. There are four different cultivars and I would like to determine if there is a difference in yield among them. I have five replicates as blocks, so the experimental design is a Randomized Complete Block Design (RCBD), and we can analyze the data using one-way ANOVA with blocks. You can download the data using R by copying and pasting the code below into your R script. After running the code, an Excel file…
This is our corn field for split N experiment in University of Guelph. Video recording by drone @ Guelph, Ontario in Canada.
New equation I suggest!! You might be already familiar with how to calculate pooled variance. This story is about pooled variance when blocks exist. If you run statistics programs, you’ll simply obtain pooled variance (also known as MSE), but you’ll never understand the concept of pooled variance if you just run software programs. Here is an example data. Let’s say this is a yield data. Cultivar A Cultivar B 120 70 130 90 110 50 Mean: 120Variance (s2): 100 Mean:…
I harvested some corn plants at R1 stage 12 days ago. Around R1 stage, final kernel number would be determined. In corn, kernel row number (girth) and number per row (length) in an ear are main yield components. Girth determination of the uppermost ear (the ear harvested) begins shortly after the ear shoot is initiated (V5 to V6) and is thought to be complete by growth stage V12, while the potential number of kernels per row (length) is finally determined…
When we set up our experimental design, it is not easy to decide the sample size because we don’t know exactly how many samples are required for our experiments. Of course the more, the better. However, eventually, we need to decide appropriate sample size according to our time and resources. For example, if we want to know the average height of students in University of Guelph, the best way is to measure all students’ height. According to Wikipedia, total number…
In corn, R1 stage (silking) is one of the most critical period to determine yield potential. The emergence of silk is regarded as the initiation of reproductive period. Each ovule (potential kernel) on the ear develops its own silk (as the stigma of the female flower). Silks initiate to elongate around the V12. It stars from the ovules near the base of the corn cob, and then sequentially developed from base to up. Silking of the tip ovules are lastly…
Sowing date: 12/05/2022 Today: 28/07/2022 (78 days from sowing) Current stage: R1 Site: Ontario, Canada Finally corn reached to R1. Now we can see corn silk will appear. Also, we regard corn developmental stage as R1 (silking) when tassels appears. It’s very important silking and tasseling are synchronized timely for successful pollination and fertilization (It would determine final yield). Environmental stresses (i.e. drought or heat, etc) would cause unsynchronization between silking and tasseling. When one appears first and another one…
When we use WordPress, sometimes we want to increase width of page. Of course, we can do that using several plugin, but through simple CSS codes, we can adjust page width and font size. Let’s go to Dashboard > Appearance > Customize Then, choose Additional CSS Then write the below code in the window. After clicking ‘Publish’, when you go back to your page, you can see your page width and font size were adjusted. FYI, if you want to…
This post is the summary of the article, ‘Ear Initiation & Size Determination in Corn’ by prof. Bob Nielsen in Purdue University, and therefore all storytelling in this post is based on the article. In a corn plant, kernel number of per ear (KN) is an important contributor to the grain yield potential. Therefore, developmental stage of corn ear is the critical period to determine KN. Environmental stress during ear development may limit the potential ear size, and therefore final…
Why plants at the front are always smaller than others inside plot? If there is a border effect, it’s likely to be taller. This mainly results from more soil compaction and also might be due to competition against grasses. Furthermore, N fertilizers would be less supplied at the front where the applicator just starts to apply N.
Sowing date: 12/05/2022 Today: 19/07/2022 (69 days from sowing) Current stage: V13-V14 Site: Guelph, Ontario, Canada Now corn is reaching to VT. Sooner or later, tassels will come out and also corn silk will appear. Now it’s so drought. When corn goes through drought stress, they roll up leaves to protect water loss. So, when you stand in corn field, you can see upper leaves look like sharp. Lower leaves start to be senescent.
Sowing date: 30/04/2022 Today: 19/07/2022 (81 days from sowing) Current stage: R1 Site: Guelph, Ontario, Canada Corn variety which was planted at the end of April reached R1 stage.
Previous post□ What is ANCOVA (1/3)? The basic concept In previous post, I explained how to interpret ANCOVA table (red box in below tables). In this post, I’ll explain how to interpret Parameter Estimates (blue box in below table) in ANCOVA analysis. Let’s check the ‘Parameter Estimates’ table. Most statistical programs set up one level of an experimental factor as “zero” and estimate the results based on that level. This concept is known as the Generalized Linear Model (GLM). If you…
Today, I will explain Analysis of Covariance (ANCOVA). ANCOVA is a statistical technique that involves including covariates, which are additional variables that may impact the dependent variable (y) in addition to the independent variable (x). I have a dataset as shown below, and I would like to analyze crop yield based on different fertilizer types (Control, Slow-release, and Fast-release). The experimental design is a Completely Randomized Design (CRD) with 10 replicates. Rep Fertilizer Yield Fertilizer Yield Fertilizer Yield 1 Control…
Previous post□ What is ANCOVA (1/3)? The basic concept□ What is ANCOVA (2/3)? How to interpret Parameter Estimates In the previous posts, I explained the basic concept of ANCOVA and how to interpret statistical results. Now, I will discuss the most important concept that is not commonly mentioned. The statistical program provided the following model in the previous posts. Control: y= 9.53 + 0.0558 xFast: y= 6.39 + 0.0558 xSlow: y= 13.10 + 0.0558 x Then, if we apply the mean…
Here is one data Then I make a regression graph. Now, I’d like to reverse the order of x-axis by descending (60 to 0). So I delete the code, scale_x_continuous(breaks = seq(-0, 60, 10), limits = c(-0, 60)) and add a new code, scale_x_reverse(limits = c(60,0)) So the whole code is below. Now, you can see the order of x-axis is changed and also the direction of the graph is changed. How to adjust unit of the axis? To adjust…
Sowing date: 12/05/2022 Today: 28/06/2022 (61 days from sowing) Current stage: V7-V8 Site: Guelph, Ontario, Canada Today is 61 days from sowing corn in Guelph. The current stage of corn is between V7 and V8. From now on, the demand of nitrogen in corn will be increased. Therefore, it would be important to track down the current stage of corn continuously. Agronomy study is always fascinated!!
The current growth stage of corn in Guelph is between V8 and V9.
scale_x_discrete(limits=rev)
Let’s create a simple dataset and draw a bar graph with this data The values on the y-axis are in decimal points. I would like to display them as percentages. So, I will insert the code labels=scales::percent inside the scale_y_continuous() function. The complete code is as follows: The values on the y-axis have changed to percentages.
#guides(color=”none”) +
I never imagined that obtaining a work permit in Canada would take this long. After waiting for 13 weeks without receiving the permit, I decided to get it at the Port of Entry and just flew to Canada. Upon arriving at Toronto Pearson International Airport, I immediately went to the Immigrant Center and waited nearly two hours to receive the work permit. When my turn came, I explained to the immigration officer that I had applied for the work permit…
Recently, I have uploaded a large excel dataset into R. This data consists of 7,849 columns. Upon checking the excel file size, it’s approximately 1MB in size. Now, I’d like to share this data with someone else. However, instead of attaching it as an excel file, I want to send it as R code, allowing them to work with the data directly in R. Therefore, all I need to do is convert this data into code. Below is how you…
After creating a graph using R, repeatedly copying and pasting it to move it becomes a cumbersome task. Today, I’ll demonstrate how to easily relocate the graph. Let’s generate some data and draw a graph to demonstrate. Running the code like this will display the graph in the Plot window. Then, each time, you’ll need to click Export, save it with a different name, or copy the image to place the graph where you want. In reality, this task is…
If you visit FAOSTAT (https://www.fao.org/faostat/en/), you can download high-quality data related to agriculture. Recently, I conducted an analysis of the trends in global and European wheat harvest quantities. As a result, I performed data analysis similar to the following. The complete code for the above graph is as follows: In the above graph, it seems that the axis title labels are too close to the axis text. I’d like to increase the spacing a bit. From now on, I’ll be…
I will introduce how to create a KML file using Google Maps or Google Earth. First, go to Google My Maps using the link below, and click on CREATE A NEW MAP. https://www.google.com/maps/d/u/0/?hl=en Then you will be directed to the following screen. Here, enter the address you want. I want to share the address of Rogers Centre in Toronto with my friend via a KML file, as I am planning to watch a Toronto Blue Jays game there. When I…
특정 국가의 취업 비자나 여러가지 입국 서류를 준비하다보면 필수 서류중 하나가 과거 체류한 국가의 범죄 경력증명서 입니다. 이미 그 나라를 떠난 상태에서 해당 국가의 범죄 경력증명서를 받기는 쉽지 않습니다. 저는 과거 네덜란드에 거주하였는데 이번 다른 국가에서의 취업비자를 준비하던 중 과거 6개월 이상 체류한 국가의 범죄경력증명서 제출이 필수여서 이번에 한국에서 네덜란드 범죄경력증명서를 발급 받았습니다. 제가 발급받았던 신청 과정을 공유합니다. 1) 범죄경력 증명서를 발급받는 홈페이지 방문 https://www.justis.nl/en/products/certificate-of-conduct 네덜란드 범죄경력 증명서는 Certificate of Conduct 라고 부르며 네덜란드어로는 Verklaring Omtrent het Gedrag-VOG 라고 합니다….
과거에 저는 밀 종자의 면적을 구하기 위해 밀 종자를 이미지 스캔하고, 그 다음에는 각 밀 종자의 면적에 해당하는 무게를 측정하였습니다. 다음 회귀 분석은 밀 종자의 면적과 무게 간의 관계를 보여줍니다. # Data download https://www.kaggle.com/datasets/agronomy4future/wheat-grain-area-vs-weight 위 데이터를 제 Github 에서 R 로 업로드 하겠습니다. 그리고 통계 분석을 해 보겠습니다. 회귀모형 y= 3.3333x – 13.7155 을 Excel 과 R을 사용하여 얻었습니다. 여기서 y 는 밀 종자 무게(mg) 이고, x 는 밀 종자 면적(mm2) 입니다. 그러나 이 모델에서, x 값이 작아지는 어느 시점부터…