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As with every growing season, the weather was challenging and required very good orchard management to get the best out of the crop.
After a warm, dry, early winter, the late winter turned cold and wet in Hawke’s
Weeds can be a real problem in young orchards, so consideration needs to be given to using residual herbicides for growing season weed control. There are numerous effective residual herbicides. For best results, these need to be applied early in the growing season to bare ground. Most need at least 10 to 15mm of rain within 7 days of application which is another reason for applying them early in the growing season when rain is more likely.
Straight after harvest is a good time to embark on some long range planning. Identify poor performing blocks, analyse possible limiting factors and determine whether or not it is worthwhile fixing the problem. If not, pull the block out and redevelop.
There is a two or three year waiting period with most nurseryman for new trees at the moment, so orchardists need to be mapping out their new tree supplies three or four years in advance to make sure they can obtain the best tree type for their situation.
Post supply is another essential input where there is scarcity. Incidentally, with the amount of dodgy quarter rounds out there that are liable to snap at knots, there will be quite keen demand for round posts to intersperse among trellis systems comprising mainly of quarter rounds.
The wet soils we now have may make it difficult to obtain a satisfactory soil fumigation job in replant sites. Correct soil moisture status is much more critical than soil temperatures in our mild winter climate for successful soil fumigation with Chloropicrin.
Try to pull orchard blocks destined for redevelopment as soon as possible, root rake them well and drain them properly before commencing preparation for replanting. In a lot of sites it will be necessary to install sump pumps to enable the site to be well enough drained for high tree performance.
The way the rain keeps on coming, it may be difficult to get the soil into the right condition for fumigation this year. Even so, for replant areas, soil fumigation is considered essential to make sure that the newly planted trees get the best start possible. It is also a very small cost relative to the total cost of planting a new intensive orchard so can be considered good insurance to make sure the trees get a good start.
There are several alternative treatments for SARD to Chloropicrin that are less demanding in regard to soil condition but unfortunately evidence of their effectiveness relative to Chloropicrin is rather lacking so it is difficult to
The soil physical assessment should involve examination of soil maps to determine the soil type and characteristics. Descriptions of the soils give valuable information on their behaviour such as drainage characteristics, rotting depth, soil moisture holding capacity, texture and water infiltration. As the soil maps are fairly extensive, there can be considerable variation across a mapped soil type, particularly on flood plains, so it is necessary to ground proof the soil map data by digging inspection pits at regular intervals across a block to view the soil profile and check for evidence of poor drainage and soil variation across a block. This is something we are not good at doing but if you visit orcharding locations with harsher climates, you will observe considerable effort going into pre-planting soil study to determine appropriate soil preparation requirements.
It is much easier to fix soil limiting factors such as a layered soil profile made up of soils with different textures before planting than afterwards. Where soils have textural layering with sharp boundary zones between the layers, movement of water and roots from one layer to the next is often impeded. This is a common cause of perched water tables leading to poor tree growth. Mixing the soil textural layers together to form a homogeneous soil 50 to 60cm deep will improve tree root growth and overcome this type of limiting factor. In some very tough soils overseas which have serious pans below that depth that impede drainage and root penetration, it is not uncommon to mix up the soil to an even greater depth with a back hoe along the row. Many of our soils have low organic matter and can be very dense. This situation impedes root growth and can slow canopy development. Where soil organic matter is low it is worthwhile considering cultivating in some compost to improve the soil structure.
Many soils have impervious layers within root zone depth, as well as compaction problems, so deep ripping across the row direction should be part of planting preparation. Once the trees are planted you cannot do this again.
Where pH and nutrient levels are below optimum, particularly in regard to phosphorus, magnesium and calcium, pre-planting applications of lime and fertiliser followed by cultivation are a good opportunity to incorporate these materials to a greater depth than is possible with post planting side dressings. In the case of magnesium which is generally in short supply on many of our orchard soils, it is not a bad idea to apply a cheaper slow release product such as magnesium oxide rather than the more expensive magnesium sulphate based Kieserite product.