Cover Cropping as a Herbicide Alternative in Vineyards
Cover cropping is not a new thing, in fact they have been grown in vineyards since ancient Roman times.
With a shift in focus towards more sustainable viticulture practices of late, there has been an increase in interest in the topic.
The main attraction behind using cover cropping in a vineyard is to reduce the use of herbicide, benefiting the overall environment as well as lowering input costs.
Other advantages include;
1) Protecting the soil from erosion – particularly in vineyards where the land is undulating or of sloping terrain, they can prevent the soil from washing under heavy rainfall.
2) Improved soil structure – an increase in organic matter in the soil helps add nutrients, particularly nitrogen which is essential for vine growth
3) Improve water-holding capacity – through improved soil structure
4) Improved soil biodiversity – An increase in organic matter provides a food source for several beneficial macro and micro-organisms. It has been noted in many vineyards that undertake cover cropping practices that there is an increased population of earthworms.
5) Improved environment for beneficial insects – Not only does the reduced chemical usage allow for this, but the crops provide a habitat and food for them.
6) Improve fauna above the soil – cover crops can provide habitat and food for beneficial insects, such as: generalist predators, parasitoid insects, spiders, and mites.
7) Cover crops can provide (if not use otherwise) firm footing which makes vineyard operations, such as harvest, pruning, and spraying during the wet weather more feasible.
8) Regulate vine growth: Cover crops can be used to both invigorate vines (augmenting soil nitrogen from nitrogen-fixing legumes) and devigorate vines (root competition from non-legumes with the vines for nutrients and water).
Choosing a cover cropping farming system will depend on the relative vigor of the site; water availability in the soil; viticultural objectives (increasing or decreasing vegetative growth); and pest management objectives for insect, mite, and weed control.
There are several different approaches that can be taken for cover cropping and they are;
Annually tilled and seeded – This system is most often chosen by growers wanting to conserve moisture in their vineyard. Cover crops are planted in autumn, allowed to grow until spring and then mowed and tilled back into the soil. This operation is often timed when the cover crop is flowering, as it will decompose easily at this stage. This system is best suited for relatively flat vineyards in which soil erosion is not a serious hazard.
Non-tillage with annual species – Vineyards are tilled initially and seeded with species that will reseed themselves on an annual basis. Thereafter, the vineyards are mowed in spring and early summer. Tillage is restricted to only beneath the vines.
Non-tillage with perennial species - Perennial species are most commonly used in vineyards planted on fertile sites. Many of the perennial grasses are very competitive with grape vine roots, and will have a devigorating effect on the vineyard. This may be desirable if the vineyard is seriously out of vegetative balance.
At PB Ag we are big believers in diverse species cropping and inter-row vineyard cover crops are no exception. When the same species are repeatedly used over time, cover crops can develop pets and pathogens which affect their productivity and persistence.
If you would like to discuss the possibility of implementing cover cropping in your vineyard, orchard or even paddocks, please don’t hesitate to give us a call on 0428404109.
Photo credit to Huntington Estate Wines
Brix testing
What is brix testing and why do we use it?
We use brix testing a lot here at PB Ag and it basically involves testing the internal sap from any plant leave, fruit, vegetable or stem.
It is carried out using a refractometer – a simple, hand-held device that measures the amount of refraction (or bend) in a beam of light that passes through the plant sap.
Refraction is the technical term scientists use to denote this light-bending effect of water and other materials. Every substance will bend or "refract" light at a different angle, depending on its specific density. This angle of refraction also changes with certain other conditions, including especially temperature, frequency, magnetism, and concentration.
How a refractometer works is that it measures dissolved solids in a liquid. The dissolved solids measured in the sap from fruit or veggies are plant sugars, vitamins, minerals, amino acids, and hormones.
The brix reading obtained from this relatively simple test that can be performed in the paddock, can tell you a lot about your crop including predicting pest pressure, yield potential, quality, shelf-life, calcium status and weed problems.
The most common thing we use brix testing for is nutrient deficiencies in crops.
Soil Microbes Part 2
Actinomycetes
In part 1 we discussed the importance of bacteria in soils – while actinomycetes are a type of bacteria, they are still classed in their own category of soil microbes.
These guys are the soil microbes which are found in the greatest abundance.
They are actually responsible for the characteristically “earthy” aroma you will get from freshly turned soil.
Actinomycetes play major roles in the recycling of organic matter.
They also inhibit the growth of several plant pathogens in the rootzone and also decompose complex components of dead plants, animal and fungal material which results in the production of many enzymes which are highly beneficial to crop production.
In addition, they are known to improve the availability of nutrients and minerals, and also enhance the production of metabolites promoting plant growth regulators.
Actinomycetes work to improve soil health by the formation and stabilisation of compost piles and stable humus.
Interestingly, these soil dwelling bacteria are also capable of producing secondary metabolites which can be used to make antibiotics and antifungals as well as immunosuppressives, insecticides and herbicides.
Soil microbes part 1
If you have anything at all to do with plants, there is a good chance at some point you will cross paths with the term ‘soil microbes’.
These tiny microorganisms play a massive part in soil health and therefore I believe, the overall productivity of a farm.
‘Soil microbes’ is a fairly loose term so I thought today we could begin to break down the different categories they fall into as well as their individual roles within the soil.
Collectively, soil microbes are known as soil microorganisms and can be broken down into the following;
· Bacteria
· Actinomycetes
· Fungi
· Protozoa
· Nematodes
Each of these have a different job when it comes to boosting soil and plant health.
We will start with bacteria!
Bacteria can be found in almost every habitat including the digestive system of animals, in salt and fresh water, in compost piles and of course in soils.
Most bacteria require well aerated soils although there are a select few that will survive in flooded soils without oxygen. They also tend to do better in soils with a neutral pH rather than acid environments.
Bacteria are among the first organisms to kick off the decomposition of residues in soil, which in turn benefits plants by increasing nutrient availability.
An example of this is nitrogen – some types of bacteria are able to take nitrogen gas from the atmosphere and convert it to a form that plants can use to make amino acids and proteins.
This is where legumes and nitrogen fixation come in – nitrogen fixing bacteria form symbiotic associations with certain legumes where the bacteria provide nitrogen for the plant and the plant provides the bacteria with sugars for energy.
A Lucerne stand for example is capable of fixing hundreds of kilograms of nitrogen per acre each year, which is stored in the soil for use by a subsequent crop.
There are many factors which can affect the effectiveness of root inoculation with rhizobia bacteria such as drought, high temperatures, soil acidity and nutritional balance within plants and the soil.
You can check legumes within your pasture quite easily to see whether they are actively nodulating and fixing nitrogen or not;
- Late winter or early spring are generally the best times to check for nodulation.
- Collect about 10 plants from three different spots in a paddock. Keep samples separate.
- Wash roots to remove soil. Plants from heavy soil may need soaking for up to 30 minutes.
- Count the number of nodules on each plant. 50 per plant is good for field peas, vetch, and faba bean.
- Soil type affects nodule numbers. There are usually fewer nodules on sandier soils.
- Check nodule location. Inoculated seed should have more nodules around the crown. If rhizobia were already in the soil, non-inoculated legumes will have nodules across the root system.
- Cut open nodules to check colour: a red/pink colour means the nodules are effective and are fixing nitrogen
- white or green nodules mean they are ineffective.
If you would like to know more about whether or not your legumes are effectively fixing nitrogen in your soils and how to encourage them to do so, please don’t hesitate to contact PB Ag today!
Why You Need The Haney Soil Health Check!
The Haney soil test has grown immensely in popularity over the last couple of years, and with good reason.
Conventional chemical soil testing methods have long been used by growers and advisors as the first step in assessing a soils ability to supply nutrients to a crop. They don’t however measure the biological processes that occur within a soil affecting availability of nutrients to plants.
In contrast, the Haney test measures overall soil health by mimicking what a plant root encounters, and by taking into account the biological processes that occur within the soil.
It involves a suite of tests integrating chemical and bio-logical factors to provide a sophisticated analysis of soil nutrient availability.
The Haney Soil Health Test was developed by USDA-ARS soil scientist called Rick Haney who after doing countless traditional field trials and plot tests on fertiliser comparisons, kept coming back to the same question; why will a control plot yield so well with no added nutrients?
Haney discovered that the answer to this quandary lay with the microbial populations within a soil and the role they play in nutrient cycling and carbon mineralisation.
Nutrient cycling involves the activity of soil microbes that utilise atmospheric oxygen, water and soil organic compounds (carbon, nitrogen and phosphorous – unavailable to plants in their elemental form) and convert them into plant available nitrogen, phosphate and CO2.
The use of this new method of testing soil for plant available nutrients, has shown that actual field conditions in nature when compared with those replicated by conventional chemical only soil testing methods are two completely different things.
In nature, rainwater is the primary solvent that initiates mineralisation of soil carbon compounds, not the acids used in most laboratories and conventional chemical based soil tests.
Another process that occurs naturally in the field is the wetting and drying of soil that affects microbial activity which flourishes during a wetting event (rain or irrigation) and slows down as the soil dries again.
The Haney test includes a wetting and drying cycle to account for this and the effect it has on nutrients available in the soil in terms of CO2 release that is a result of microbial activity.
So what does all of this mean for you as the grower?
The Haney Soil Health test allows producers to see how their management systems are affecting the microbial community and therefore the availability of nutrients to plants.
This in turn allows you to reassess fertiliser budgets and applications as often these tests show there is more nutrients within the soil that only needs to be made available through the manipulation of microbial activity.
It also brings back into question the theory behind cover cropping, multispecies cropping and also sensible cropping rotations.
More on that later.
If the Haney Soil Health test is something you would like to start implementing in your farming system, PB Ag can assist you in doing so.
Call Paul on 0428 404 109.
how will bush fires affect this years grape harvest?
With bush fires of catastrophic proportions wreaking havoc in the heart of some of our biggest wine growing areas, a timely topic for discussion would have to be smoke exposure of grapevines and the development of smoke-related characteristics in wine produced.
Prolonged and intense exposure to smoke during sensitive growth stages of grapes can result in the fruit exhibiting aromas and flavours resembling smoked meat, disinfectant, leather, salami and ashtrays.
Depending on concentration levels, these unfavourable smoke characteristics when detected by consumers can render wine unpalatable, causing it to become unsalable and obviously resulting in substantial financial losses for producers.
Worst case scenario, the indirect costs of such a problem can then flow on to wine brands, market presence and future sales.
During the Canberra bushfires of 2003, the Alpine Valley wine industry suffered a loss of an estimated $4 million and caused severe smoke damage to other vineyards in north-east Victoria and south-eastern NSW.
In 2009 the Black Saturday fires in Victoria were estimated to cost the industry $299 million in revenue.
The effects of smoke uptake in wine is dependent on variety and there have been extensive studies done on Merlot, Cabernet Sauvignon, Chardonnay and Sauvignon Blanc.
The studies showed that timing of smoke uptake varies with variety, with some being more sensitive earlier in their growth than others.
Seasonal weather conditions, overall vine health and plant structure including berry skin thickness can also affect smoke uptake in fruit.
Studies have shown that wine from white grape varieties generally have fewer smoke related sensory and chemical effects due to the reduced contact time on skins when compared with red wine production.
Wine making with smoke exposed fruit requires the use of additional tools and techniques to reduce the level of taint in the wine.
It has been shown that smoke related volatile phenols will accumulate in freshly crushed grapes during fermentation, and they will further accumulate after malolacticfermentation.
The rate of fermentation can be accelerated with smoke effected grapes, and these smoke related phenols will accumulate even further during storage in a bottle over time.
The amount of phenols present can be reduced during winemaking through various methods of fruit handling and during the fermentation process.
Hand harvesting grapes being careful to exclude leaf material as well as whole bunch pressing, separation of press fractions, yeast selection and reverse osmosis have all proven to reduce smoke related flavours and aromas in wine.
There are also various methods of assessing fruit that has been exposed to smoke to determine what the likelihood is of undesirable characteristics affecting wine produced.
If you are a grape producer in an area recently affected by bushfires, and/or the ensuing smoke, and would like more information or assistance in assessing vines and fruit for potential effects, please contact PB Ag today!
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Making hard choices in drought conditions
It’s no secret, 2019 has been the toughest year yet for many.
With the big dry continuing and the rain forecast failing to illuminate any ‘lights at the end of the tunnel’, farmers everywhere are facing the big decision of whether to hang onto stock or let them go.
Some have already bitten the bullet and reduced numbers while others are of the mind that they are already so far into it all, they might as well keep going for as long as they can.
Without a looking glass and the ability to probe into the future, decisions like this are incredibly hard ones to make and one with many factors to be considered.
As a general rule there are three components that contribute to the final decision;
1) Economics – the longer the drought continues, the more expensive feed becomes. Once you’re committed to feeding stock, you lose all control over the price and length of time you’re going to have to do it for.
2) Environmental – It is important to consider the impact on your pastures and water sources.
3) Personal stress levels – the stresses of drought for a farmer far exceed the immediate and obvious ones of having to source feed and water.
With our climate becoming more and more unpredictable, the most important tool any producer can arm himself with is a plan.
Keeping an eye on rainfall patterns and looking ahead to see what is in the forecast can allow you to make a basic plan outlining the steps needed if it were to turn dry.
These would include what stock would be sold first, and when regardless of what the market is doing.
Managing pastures during drought conditions is a fine art and requires knowledge of agronomic factors, livestock requirements and environmental limitations.
Stock should be removed from a paddock after they have grazed pasture down to 1000kg DM/ha. Stock containment areas or sacrifice paddocks should then be used until pasture has had a chance to regenerate to at least 1500kg DM/ha/.
Sacrifice paddocks should be nominated based on their low value or degraded pastures – sacrificed to save priority paddocks from overgrazing.
As far into the drought as we are now, there are many places around with very little ground cover left and so the above no longer applies.
In this case, it is important that we look forward to what we can do when it does finally rain and we have the opportunity to regenerate pastures.
After such a long dry period where it is unlikely annual grasses will have the opportunity to set seed, perennials coming back need to be managed carefully so as to encourage maximum growth.
Weeds may make up a large portion of a post-drought pasture and available stock feed. Care needs to be taken when making decisions on how best to control them.
Spray with caution as doing so can increase palatability and cause toxicity issues for stock. Rotational grazing of emerging weeds is one control option that can be considered.
While PB Ag unfortunately can’t make the big decisions for you in terms of whether to sell stock or hang onto them, we can certainly assist you with obtaining the right information to ensure you’re making the most informed decision possible.
We are also able to help you make plans around drought and pasture management to help you remain sustainable for the longest time possible.
Please don’t hesitate to give us a call if you would like some assistance in reviewing or putting into place a drought management plan.
Getting the most from your irrigation system
Irrigation Efficiency
The ability to irrigate in dry times such as these is an absolute privilege and an opportunity afforded to what seems like a minority at the moment.
Still, driving around I shudder to see how much water is being wasted due to inefficient irrigation practices with irrigators operating in 40km/hr plus winds and/or in the hottest part of the day as well as growers blindly applying water to paddocks with no real insight into how much of this water is actually being utilised by plants.
Inefficient irrigation practices are hurting your bottom line – under-watering or over-watering will obviously significantly impact farm profitability.
Now more than ever during these less than ideal seasonal conditions, it is imperative that we really tighten up on our irrigation systems and make sure that every drop of water we are putting out, is doing its part in achieving the best bang for our buck.
In other words, the aim of efficient irrigated agriculture is to get maximum production for the same or less input: for example, growing more crop with the same or less amount of water.
Assessing the efficiency of a producers irrigation system also requires the distinction between the agronomic performance of the crop (crop water use index) and the engineering aspects of the design and management of the system (irrigation index or efficiency).
A crop water use index compares an output from the system, such as yield or economic return, to crop evapotranspiration.
In contrast, an irrigation index or efficiency often compares an output, such as yield, economic return or amount of water retained in the root zone to an input, such as some measure of water applied.
There are a whole range of benefits to be gained from a correct assessment of current irrigation practices on farm as well as following through with the necessary adjustments where required.
These include but are not limited to; maintaining or increasing production from existing or less amounts of water, expanding irrigated areas and reducing water wastage leading to conservation of resources and a saving on farm overheads.
In addition to the on-farm benefits, many environmental benefits can also be obtained from improving irrigation and water use efficiency.
Concerns about rising water tables contributing to water logging and salinity in some areas have highlighted the benefits of reducing accessions to the groundwater table.
Reductions in excess water use can also minimise the movement of pesticides, nutrients and salt downstream, reducing damage to aquatic ecosystems and other downstream water users.
If it is time to take a hard look at your current irrigation practices, but you are unsure of where to start, please don’t hesitate to give PB Ag a call.
We are happy to meet with you on farm and assist you in making sure your irrigation system is running at peak efficiency levels.
Slip, slop, slap - sunscreen for grapes!
Day 3 of Summer 2019 and it’s already shaping up to be a doozy.
Wine growers in many areas are already looking down the barrel of a series of predicted heat waves coupled with lower than average rainfall.
It may be time to consider the old slip, slop, slap method for grapes this season – that’s right, I actually want to talk about sunscreen, for grapes!
Heat waves that follow the onset of ripening in vineyards can directly impact fruit condition as well as delay ripening due to fruit sunburn or scorch.
Generally speaking, a series of consecutive days reaching temperatures of over 35 degrees, or a single day of over 40 degrees Celsius can be considered a ‘heat event’ in vineyards.
Some grape varieties are more susceptible to these heat events and to berry sunburn than others, and it can influence wine quality resulting in undesirable phenolic flavours.
As grapes soften, they become more susceptible to damage from heat waves. Dark coloured grapes even more so as they absorb more radiation and may get much hotter than the surrounding air temperature.
Overall bunch temperature and potential for sunburn damage is determined by the following;
1) Air temperature
2) Absorbed radiation (from both incoming and also reflected radiation)
3) Convective heat loss (evaporation and transpiration)
4) Vine water status
5) Radiation load
6) Wind velocity
7) Degree of exposure
8) Berry/bunch size and compactness
9) Berry colour – white and green berries prior to veraison don’t get as hot.
Symptoms of berry sunburn can include browning, cracking and shrivelling and at this point, yields have already been reduced and fruit will most likely be downgraded causing significant economic loss to the grower.
Studies have shown that on some varieties, sunburn symptoms can appear within five minutes once surface temperature on the berry reaches an ambient temperature of 40 – 43 degrees Celsius.
Fortunately, we now have the option of applying commercially available kaolin clay based ‘susncreen’ products to vines, which have been shown to reduce berry temperature and the impact of sunburn during heat events.
This summer is shaping up to be a challenging one for grape growers in terms of high temperatures and low rainfall and so presents a prime opportunity to be employing the use of these sunscreens in your vineyard.
If you would like to know more about these products and the benefits they offer, please feel free to drop me an email, send me a Facebook message or give me a call on 0428 404 109.
The Importance of Buying Certified Seed
While some might be struggling just to come to grips with trying to organise their summer cropping program in such adverse conditions, ag consultants are urging farmers to start planning even further ahead into their next autumn sowing.
The forecast for seed supply heading into next year is looking rather grim. With limited supply off the back of a less than ideal season, be warned – seed will be expensive and difficult to source.
As with most things, you get what you pay for and seed is no exception to this rule. Good seed will be expensive and coming out of already tough times producers will be reluctant to pay for it.
As an agricultural consultant who spends a lot of time on the road assessing crops, I urge you to please not be tempted into buying the cheap unknown option when it comes to seed – be it oats, barley, wheat or whatever you’re chasing.
While you might save yourself a few dollars in the short term, you can soon find yourself backsliding on those savings through unexpected costs in poor germination, low rust tolerance, poor vigor, high weed contamination etc.
Low Germination
If you do for whatever reason decide to go with a low budget option seed, at the very least please do a simple home germination test before sowing.
All you need is a plate, some cotton wool, water and 100 seeds counted out – just like the old school science experiment.
This way you will get a rough estimate of the germination rate of your seed, so you can adjust sowing rates accordingly.
This is the first place you will lose out on your apparently low budget option – even though you may have obtained your unknown seed for $200/t less, by the time you increase your sowing rate to offset the poor germination quality, you will end up coming up even in costs and in some cases, it will actually end up costing you more due to the heavier sowing rates required.
Weed Contamination
A few years ago, there was a significant issue with wild radish popping up in oat crops all around NSW.
This was due to a shortage of seed oats supply resulting in producers sourcing seed out of Western Australia.
The added bonus that came with the wild radish was that it was extremely herbicide resistant, leaving producers with limited options for chemical control, all of which were highly costly.
This is not an uncommon problem when buying unknown seed, and a risk for which you leave yourself wide open.
When you buy from a reputable local seed supplier, or at the least purchase a tested and certified product, you are getting a known variety with accurate and reliable measurements of germination rate, forage performance, rust and disease tolerance and importantly it has been cleaned, graded and treated.
As previously mentioned, seed will undoubtedly be in short supply moving into the autumn sowing window. I strongly advise that producers start looking to secure theirs now.
If you would like assistance in choosing a suitable variety for your cropping program, or need help securing the variety you have chosen, please don’t hesitate to contact PB Ag today!
Mite Control in Vineyards
In the last few weeks I have been working with grape growers on getting their sulfur applications out in vineyards to address the problem of mites.
Too often we tend to wait until we can physically see the damage caused by pests in vineyards, pastures and crops alike before acting.
By that stage it is often too late to achieve an acceptable level of control, and what damage has been done is sometimes irreversible and has already inhibited growth or production in some way.
What many growers are unaware of is that some pesticides on the market can actually harm predatory mites and other natural enemies of pest mites. Sulfur is safer than many other commercial pesticides and will not harm beneficial insects.
Common Mites found in vineyards
Rust mite damage is often seen as significant bronzing in the late summer/autumn. These mites will become dormant during winter so it is an important to time your control measures correctly.
There is only a small window in which control methods will be successful. This window is during the mites migration from their sheltered, over-wintering sites and before leaf expansion provides them with shelter from sprays and before they can lay their eggs.
Blister mite and bud mites are two species which are intrinsic to grapevines. Almost identical in appearance, the damage they cause varies due to their feeding habits.
As their name suggests bud mites feed on and damage young buds before they burst while blister mites cause a galling effect on leaves.
Spraying vines with sulphur to control these mites is most effective immediately after 100% budburst when the highest coverage can be achieved.
Sulfur sprays work against mites by causing respiratory problems in the mite – essentially suffocating them. Therefore, it is essential to achieve maximum coverage of vines to reduce “hiding spots” for the mites, and areas where they can shelter and avoid the sulfur residue.
If you would like more information regarding pest control in your vineyard, orchard, or paddock please don’t hesitate to drop me an email at paul@pbag.com.au or to give me a call on 0428 404 109.
Uneven Bud Burst in Grapevines
Travelling around the region right now doing bud counts in vineyards, one common theme among them seems to be Restricted Spring Growth or RSG.
RSG basically describes poor shoot growth and poor yield development during the spring period.
While RSG can be attributed to many varying factors, this season the main offender is the hard winter we have experienced coupled with a lack of rainfall in many areas.
The lack of soil moisture at bud burst and early in the growing season has affected the rates of photosynthesis and a range of other metabolic functions related to the growth of shoots.
One major symptom I am seeing at the moment is failed and patchy bud burst as well as poor shoot growth.
It is of paramount importance to monitor vines and environmental conditions over the winter dormancy period. Low rainfall and drier than normal weather conditions during this period and in the early phases of bud burst and shoot growth can have a significant influence on the expression and severity of RSG symptoms.
Efficient irrigation scheduling is a complex task which requires extensive knowledge of a whole host of agronomic factors.
In a nutshell, the interval between irrigation's and the amount of water to apply at each irrigation depend on how much water is held in the root zone and how fast it is used by the crop.
This is determined by
• soil texture
• soil structure/water penetration
• depth of effective root zone of the soil
• the crop grown
• the stage of development of the crop.
All soils are composed of solid particles of various sizes, organic matter, and pore spaces that hold air and water. The size of these pores, and the amount of water they hold, depends on the texture and structure of the soil which directly effects how much water a vine needs, and how often it needs it.
If you are concerned about uneven bud burst in your vineyard, or would like help gaining a firmer handle on the monitoring of your vines including irrigation and nutrient scheduling to increase quality and quantity of your yield as well as avoid issues such as RSG, give PB Ag a call today.
Travelling around the region right now doing bud counts in vineyards, one common theme among them se