There are 20 essential nutrients necessary for complete plant growth and development. Not all are required for all plants, but all have been found to be essential to some. Three of the 20 (carbon, hydrogen, and oxygen) and are derived from CO2 and H2O and are not usually considered in terms of managing a plant nutrition and soil fertility program.
The remaining 17 are commonly referred to as mineral nutrients (N, P, K, Mg, Ca, S, Fe, Mn, Mo, Cu, B, Zn, Cl, Na, Co, V, and Si). Of the 17 mineral nutrients, N, P, and K are the macronutrients; Mg, Ca, and S are secondary nutrients; and Fe, Mn, Mo, Cu, B, Zn, Cl, Na, Co, V, and Si are referred to as micronutrients. The terms macro-, secondary, or micronutrients do not refer to any level of importance but rather to relative amounts required by plants.
The amount of a given nutrient found in a plant will depend on several; factors, governed in general by a broad range of plant and environmental interactions. The percentage composition of plant nutrients can vary considerably among species and locations. Since all the mineral nutrition is provided to the plant by nutrient uptake from the soil through the root system, an understanding of the soil conditions and the effects on plant nutrition are very important.
There is usually a rather poor relationship between the total amount of a given nutrient found in the soil (i.e., P or K) and the amount available to the plant for uptake and utilization. This is certainly true in Arizona where our agricultural soils are commonly rather young (geologically) alluvial soils with a high native fertility level.
Soil tests are commonly used to establish a relationship between an estimated level of a “plant-available” form of a given nutrient and its sufficiency, deficiency, or toxicity for the crop in question. The relationships between a soil test and actual crop nutrient needs are usually specific for a crop and region and a set of common soil conditions.
Developing a sound fertilization program begins with a good understanding of actual soil conditions. The collection and analyses of a good(representative) set of soil samples and then relating that information to established guidelines are the first steps toward developing a strong soil fertility and plant nutritional management program for any crop. This is important for the overall efficiency of a crop production system, including agronomic, economic, and environmental efficiency.
To maximize nutrient management efficiency, it is good to consider the 4R concept of plant nutrient management and application, consisting of:
1. Right fertilizer source at the
2. Right rate, at the
3. Right time and in the
4. Right place
The 4R nutrient stewardship approach utilizes the implementation of best management practices (BMPs) that optimize the efficient use of fertilizer by the crop. The primary objective of the 4R approach and BMPs is to match nutrient supply with crop requirements and to minimize nutrient losses from fields. Each case can vary among farms and fields, dependent on local soil and climatic conditions, crop, management conditions, and other site-specific factors.I hope you are frolicking in the fields of wildflowers picking the prettiest bugs.
I was scheduled to interview for plant pathologist position at Yuma on October 18, 2019. Few weeks before that date, I emailed Dr. Palumbo asking about the agriculture system in Yuma and what will be expected of me. He sent me every information that one can think of, which at the time I thought oh how nice!
When I started the position here and saw how much he does and how much busy he stays, I was eternally grateful of the time he took to provide me all the information, especially to someone he did not know at all.
Fast forward to first month at my job someone told me that the community wants me to be the Palumbo of Plant Pathology and I remember thinking what a big thing to ask..
He was my next-door mentor, and I would stop by with questions all the time especially after passing of my predecessor Dr. Matheron. Dr. Palumbo was always there to answer any question, gave me that little boost I needed, a little courage to write that email I needed to write, a rigid answer to stand my ground if needed. And not to mention the plant diagnosis. When the submitted samples did not look like a pathogen, taking samples to his office where he would look for insects with his little handheld lenses was one of my favorite times.
I also got to work with him in couple of projects, and he would tell me “call me John”. Uhh no, that was never going to happen.. until my last interaction with him, I would fluster when I talked to him, I would get nervous to have one of my idols listening to ME? Most times, I would forget what I was going to ask but at the same time be incredibly flabbergasted by the fact that I get to work next to this legend of a man, and get his opinions about pest management. Though I really did not like giving talks after him, as honestly, I would have nothing to offer after he has talked. Every time he waved at me in a meeting, I would blush and keep smiling for minutes, and I always knew I will forever be a fangirl..
Until we meet again.
Interested in staying up to date on the latest robotic ag technologies? FIRA USA and a number of other entities are organizing a 3-day forum focused on autonomous farming and agricultural robotics solutions. The event will be held October 22-24 in Woodland/Sacramento, CA. The program includes top-level keynote speakers, breakout sessions, a trade show and field demos. Over 35 robots will be demoed and/or on display including 8 machines designed for weeding vegetable crops. Some of the latest technologies for in-row weeding will be featured including lasers (2 companies) and high precision spot spraying (3 companies). If you are interested in ag tech, FIRA 2024 promises to be a quality event and one well worth attending. For more information, visit https://fira-usa.com/.
Fig. 1. Robotic technologies on display and being demoed in the field at
FIRA USA 2024. The event will be held October 22-24 in Woodland/Sacramento,
CA. (Photo credits: FIRA USA).
Boerhavia coulteri is a flowering plant that belongs to the Nyctaginaceae or Four O'clock family known by the common name Coulter's spiderling. Its native to the desert areas of the SW in the US and North of Mexico. It is a summer annual or perennial weed producing an erect or creeping stem up to 0.7-0.8 m in length. Grows in disturbed areas, ditch banks, and roadsides.
The cotyledons are oblong,1.0-2.5 cm.
Plants are slightly pubescent with sticky resin glands toward the bases. The leaves are lance-shaped, somewhat triangular, pointed, sometimes wavy or rippled along the edges, and 5 centimeters in maximum length1.
We have this weed in our Yuma County AZ and very abundantly in the sandy soils of the Yuma Mesa.
I added a table from a weed control experiment conduced for Boheravia erecta.
The Research Paper called :” The effect of herbicide tank mix on the weed species diversity
in sugarcane (Saccharum officinarum)” mentions: “All the herbicide mixes significantly controlled Boheravia with Pendimethalin. Being Pendimethalin plus Atrazine the best treatment as shown in the table below.
I am delighted to embark on my first produce season here in Yuma, AZ. I am looking forward to becoming acquainted with the growing region this fall as we begin identifying tools that can enhance our pest management strategies, specifically focusing on organic solutions for managing insect pests in the Desert Southwest. It is also important for me to gain a deeper understanding of the challenges and issues you are facing in the field. We are eager to evaluate both current and new biopesticides in our upcoming trials and look forward to engaging with potential collaborators.
Here is a list of our fall 2024 trials:
1- Evaluation of selected bioinsecticides against Lepidopteran pests in Brassicas
2- Evaluation of selected bioinsecticides against whiteflies in Brassicas
3- Alternative bioinsecticides for thrips management in lettuce
4- Assessing the effectiveness of beneficial insects (T. brassicae, T. pretiosum, and green lacewings) release for diamondback moth control in Brassicas
I hope everyone’s season gets off to a fantastic start. Please contact me or Macey if you have specific pest issues, biopesticides, or other organic IPM practices you would like us to evaluate. Your expertise is truly invaluable to us!
Contact Information:
• Wilfrid Calvin
Assistant Professor & Extension Specialist
Cell: (979) 709-9762
Office: (928) 782-5861
e-mail: wilfridcalvin@arizona.edu
• Macey Keith
Assistant in Extension
Cell: (928) 580-5785
e-mail: maceyw@catmail.arizona.edu
Both organic and conventional lettuce are high-demand crops for nitrogen, with organic lettuce requiring organic nitrogen and conventional lettuce requiring general nitrogen sources. Lettuce requires a substantial amount of nitrogen to support its growth, particularly during the heading stage when most nitrogen uptake occurs. This demand is driven by its rapid growth rate and the production of large leaf biomass.
Organic nitrogen/nitrogen management for lettuce production in Yuma, Arizona, is acritical aspect of efficient and sustainable agriculture. Proper nutrition(organic nitrogen or nitrogen) management can improve crop yield, reduce environmental impact, and optimize resource use. This is significantly correlated with sufficient soil moisture availability. As a result, improper or excessive water and nutrient management for both organic and conventional lettuce production systems could significantly and negatively impact growth, development, and yield quality.
Moreover, several studies have reported that proper water and nitrogen management could potentially reduce aphid attraction to lettuce, as aphids are more prevalent in lettuce with higher nitrogen content. Elevated nitrogen levels in lettuce can attract and support larger aphid populations.
There are many approaches that could be adopted for coupled water and nutrient management, or in other words, best management practices to avoid excessive or inadequate application of either element. After soil sample analysis in the pre-season, one of these approaches involves utilizing high-tech site-specific sensors, which can be installed between two healthy plants that represent the majority of the field to monitor nitrate-N levels in the soil throughout the growing season. These sensors monitor nitrate-N levels on a daily or weekly basis to evaluate nutrient levels at different soil profile depths, especially during critical lettuce growth stages. Many studies have reported that site-specific, sensor-based nutrient management increases efficiency compared to traditional methods, resulting in significant nitrogen savings.
Preliminary results from ongoing research comparing nutrient levels by utilizing AquaSpy Nitrate sensor (Figures 1. 2. And 3) with soil analysis conducted in the lab (Ward Laboratories Inc.) as part of the study on organic vs. conventional iceberg lettuce under subsurface drip irrigation at the Yuma Ag Center-Valley Research Center, suggest that the findings are comparable to a considerable extent so far. Soil moisture availability and soil temperature fluctuations significantly influence the data reflected by the sensors, particularly at varying profile depths. This is an ongoing project; however, the results are promising regarding the aforementioned objectives in organic and conventional lettuce production systems. Stay tuned for the results and conclusions after harvesting.
Figure 1. Nitrate sensor from AquaSpy was installed between two healthy plants in the
organic lettuce production field at the Valley Research Center at the University of
Arizona, Yuma Agricultural Center, Yuma, Arizona.
Figure 2. Nitrate level in the conventional lettuce production field at the Valley Research
Center at the University of Arizona, Yuma Agricultural Center, Yuma, Arizona.
