Grain crops - stubble management and nitrogen fertiliser

Farmers burn crop stubble in a rice field at a village in Fatehgarh Sahib district in the northern state of Punjab, India, November 4, 2022. REUTERS/Sunil Kataria

The Victorian department of agriculture describes current Australian farm practices for stubble management in wheat cropping. A number of options are discussed. 

For example, at "Crops and horticulture - Managing stubble", 

Crop stubble is the straw and crown of plants left on the soil surface after harvest. Stubble also includes straw and chaff discharged from the harvester (header). It is also known as ‘residue’ or ‘trash’.

Stubble management is one of many complex issues that farmers must contend with. Traditionally, grain growers have burnt stubble to manage weeds, diseases and reduce biomass to make sowing easier. This is no longer the preferred option. Numerous other methods can be used to manage stubble.

Retaining stubble, rather than burning or cultivating, protects the soil from erosion. It also conserves soil moisture and organic matter to sustain crop production. This is particularly beneficial in dry areas or in dry seasons.

A new piece of information discussed by a Canadian soil scientist - that spreading plant material with a high carbon:nitrogen ratio before it has been composted - can reduce soil nitrogen. 

 

Old tree leaves are a staple of fall but it seems wasteful to simply throw them into the garbage. However, applying these [and wheat stubble] to your garden the wrong way can be equally as damaging to your soil nutrients. This article looks at how to use old tree leaves in your garden properly.

If it is true that the same process occurs, reducing soil nitrogen with wheat stubble retained in fields after harvesting, the result will be an increased need for nitrogen fertiliser. 

Nitrogen fertilisers are increasingly expensive, and most are made from natural gas with significant carbon dioxide emissions.  

The soil scientist's advice suggests the need for nitrogen fertiliser may be lowered by harvest wheat stubble and compost it with fungi before spreading the composted stubble on fields. 

A small-scale experiment could evaluate the potential benefit of harvesting wheat stubble instead of leaving it to compost in contact with fields, and then spreading the composted wheat stubble to return nutrients and to increase soil carbon.

Work on this possibility has been completed in India: 

The smog choking New Delhi has been linked to the burning of crop stubble. Every year, most farmers in North India clear their paddy fields by burning an estimated 23 million tonnes of straw. This year, local officials have introduced a revolutionary method in a bid to tackle air pollution. Developed by the Indian Agricultural Research Institute, the bio-decomposer mixture of fungus, jaggery [an unrefined sugar product made in Asia], gram flour and water can help break down the stubble and turn it into compost that will help fertilise the land in just two to three weeks. 

 

Fruit picking drones with human operators

Horticulture could benefit from automation that combines fast, repetitive actions by a robot with a human operator who provides rapid, accurate identification of fruit to be picked. 

The combination of a human operator and an automated picking machine has a number of advantages. 

A human operator would be able to pick a much larger number of pieces of fruit than either a worker or a robot alone. Fewer workers would be needed, wages could be higher because of higher productivity, and remote operation means more people would be available to pick crops. Fruit-picking could be done from the comfort of the workers' own home. 

The software could be developed as a computer game, with players identifying as many objects to be picked by a robot within the game to advance to higher levels. 

Once perfected as a game, the automated component - the fruit-picking robot - would be driven by the game-player's input just as the game-based robot was. The fruit-picking robot designer need only address the challenge of picking an identified piece of fruit after the game player has chosen it and provided the precise location. 

The video below demonstrates actions a fruit-picking robot needs to replicate - 

 

The game-player in the development version could control the game with a VR headset that includes eye-tracking to obtain information on the precise location and choice of pieces of fruit to be picked. 

The video below gives a description of this type of operator interface to a game or a fruit-picking robot -

A company offering VR headsets with eye tracking for computer game development, Tobii, describes its capabilities as: 

What is eye tracking in gaming?

An eye tracker gives your computer the knowledge of where you are looking on-screen. Eye tracking technology can enhance your gameplay experience by allowing you to use head and eye movements to control the in-game camera, and to affect and interact with game environments. 

Flood Control - an idea out of left field

 Is it possible to siphon water through an inflatable tube? 

Siphoning water from one level to another

The town to protect - raising water level upstream and maintaining constant water level downstream

Inflatable flood barriers

 

Can water be siphoned through an inflatable tube?

Can the water pressure in an inflatable tube be maintained by inlet and outlet flow control vanes so that water can be siphoned through it, or will the tube invariably collapse when trying to siphon water through it?

Replacing sandbags with water-filled inflatable tubes, and using the same tubes to siphon water from upstream of a town to downstream of the town would be an improvement over filling sandbags, allowing some of a floodwater peak to be moved through the town via above ground tubes that also serve as a flood barrier.

Less back-breaking work than filling and stacking sandbags.

 

Sandbags in Echuca, Victoria. (ABC News: Sarah Lawrence)

A challenge to heat and cool buildings efficiently

The efficiency with which we can heat and cool rooms requires a good solution for maintaining low carbon dioxide levels in well-insulated rooms.

Exchanging large volumes of air from inside to outside when the outside air temperature is very cold or hot could be a very costly way to remove small amounts of carbon dioxide.

 

An adult uses about 500 litres of oxygen while breathing about 10,000 litres of air in and out per day.  

See "Oxygen a person uses each day."

A carbon dioxide concentration of 1,400 ppm reduces decision-making ability by 25%. 

See "Rising carbon dioxide ...may directly harm our ability to think."

How much does the CO₂ concentration increase in one day, depending on the total volume of air in a sealed room, with one person occupying it? 

A room that is 4 metres long by 4 metres wide and 2.5 metres high has a volume of 40 cubic metres. 

It contains 40,000 litres of air of which about 32,000 litres (80 percent) are nitrogen and about 8,000 litres (20 percent) are oxygen. 

One person will use about 500 litres of oxygen in a day. So the 8,000 litres of oxygen in this room is ample for one day. However, the small amount of carbon dioxide the person exhales raises the concentration of carbon dioxide so that quite soon it will interfere with the person's ability to think clearly if it is not removed.

One person sleeping or working in this room alone for 8 hours would raise the carbon dioxide concentration to over 4,000 ppm if there was no exchange of air from outside, and no method to remove the carbon dioxide being added. 

The relatively small amount of carbon dioxide - increasing by 21 litres per hour - requires a large volume of air in the room - 40,000 litres - to be either exchanged or otherwise processed each hour to maintain the carbon dioxide concentration at a constant level.

Classrooms with high carbon dioxide levels may be lowering education outcomes for children because their ability to concentrate is being reduced.

Hour	Air Breathed (L)	N2 (L)	O2 in (L)	O2 out (L)	CO2 out (L)	CO2 conc (ppm)
0	-	-	-	-	-	-
1	417	333	83	63	21	521
2	833	667	167	125	42	1,042
3	1,250	1,000	250	188	63	1,563
4	1,667	1,333	333	250	83	2,083
5	2,083	1,667	417	313	104	2,604
6	2,500	2,000	500	375	125	3,125
7	2,917	2,333	583	438	146	3,646
8	3,333	2,667	667	500	167	4,167
9	3,750	3,000	750	563	188	4,688
10	4,167	3,333	833	625	208	5,208
11	4,583	3,667	917	688	229	5,729
12	5,000	4,000	1,000	750	250	6,250
13	5,417	4,333	1,083	813	271	6,771
14	5,833	4,667	1,167	875	292	7,292
15	6,250	5,000	1,250	938	313	7,813
16	6,667	5,333	1,333	1,000	333	8,333
17	7,083	5,667	1,417	1,063	354	8,854
18	7,500	6,000	1,500	1,125	375	9,375
19	7,917	6,333	1,583	1,188	396	9,896
20	8,333	6,667	1,667	1,250	417	10,417
21	8,750	7,000	1,750	1,313	438	10,938
22	9,167	7,333	1,833	1,375	458	11,458
23	9,583	7,667	1,917	1,438	479	11,979
24	10,000	8,000	2,000	1,500	500	12,500

You can add mechanical ventilation to your home with a heat recovery ventilator (HRV) or energy recovery ventilator (ERV). Both exhaust air from the house and bring in outdoor air to replace it. There's a heat exchanger to bring the incoming air to a better temperature.

5/11 pic.twitter.com/geOQQnTecQ

— Joey Fox, P. Eng, M.A.Sc (@joeyfox85) July 20, 2022

Below are extracts from two articles - the first on symptoms in people in rooms with elevated levels of carbon dioxide, the second on symptoms of people in hotel quarantine. 

The similarities may indicate that people in hotel quarantine were being affected by elevated carbon dioxide levels, and not the fact that they were in quarantine. This could be evaluated by comparing the group in hotel quarantine with the experiences of those in quarantine at Howard Springs with self-contained units and access to fresh air.

Rising carbon dioxide ... may directly harm our ability to think

Extract from article published in ScienceDaily:

"It's amazing how high CO2 levels get in enclosed spaces," said Kris Karnauskas, CIRES Fellow, associate professor at CU Boulder and lead author of the new study published today in the AGU journal GeoHealth. "It affects everybody -- from little kids packed into classrooms to scientists, business people and decision makers to regular folks in their houses and apartments."

Shelly Miller, professor in CU Boulder's school of engineering and coauthor adds that "building ventilation typically modulates CO2 levels in buildings, but there are situations when there are too many people and not enough fresh air to dilute the CO2." CO2 can also build up in poorly ventilated spaces over longer periods of time, such as overnight while sleeping in bedrooms, she said.

Put simply, when we breathe air with high CO2 levels, the CO2 levels in our blood rise, reducing the amount of oxygen that reaches our brains. Studies show that this can increase sleepiness and anxiety, and impair cognitive function.

They found that ... indoor concentrations ... of 1400 ppm to be harmful.

"At this level, some studies have demonstrated compelling evidence for significant cognitive impairment," said Anna Schapiro, assistant professor of psychology at the University of Pennsylvania and a coauthor on the study. "Though the literature contains some conflicting findings and much more research is needed, it appears that high level cognitive domains like decision-making and planning are especially susceptible to increasing CO2 concentrations."

In fact, at 1400 ppm, CO2 concentrations may cut our basic decision-making ability by 25 percent, and complex strategic thinking by around 50 percent, the authors found.

Hotel Quarantine And Mental Health

Extract from article by Giulia Fiore, psychologist and founder of Confidence to Achieve:

Hotel quarantine is a costly procedure that necessitates a highly specialised workforce to sustain the system, which includes clinical, welfare, and security services, in order to minimise risk and meet the duty of care obligations. The effects of hotel quarantine on mental health and wellness are arguably one of the most important factors in the hotel quarantine scheme, as even those who have never encountered mental illness may find the experience taxing.

Isolation and quarantine have been shown to have negative mental health effects, including depression, anxiety, stress-related disorders, anxiety and anger. In a rapid study, Brooks et al. found that people who were quarantined have more negative psychological effects, such as post-traumatic stress symptoms, confusion, and frustration. Furthermore, citizens in a state of confinement can experience restraint and express fixation on the disease’s progress, as well as psychosomatic symptoms such as insomnia.