These are just some of the questions being asked by
wetter year (pictured right). A penetrometer (pictured over) can be used to determine the resistance of soil at given moisture level and depth. So, I decided to get out the old penetrometer and do some testing. I determined at a soil depth of 20 to 50cm there was resistance ranging between 550-700 psi across wheel tracks suggesting moderate to severe compaction down to a soil depth of 30-40cm. Adjacent furrows without traffic ranged between 250-400 psi. Research has shown that soils with a resistance >300 psi would limit root growth (Hamza and Anderson, 2005), which would have a potential impact on the following crops production. The question that many need to ask themselves this year if they are in the above situation, what is my realistic yield potential and how do I manage my crop to that expectation?
Agronomists and farmers across the industry. Many researchers, organisation’s and industry members have been conducting work in the areas of soil health and the potential consequences of soil compaction in our farming systems with the use of larger and heavier equipment whether it be a harvester or tractor. Compaction is on the mind of a lot of growers who are trying to increase long- term farming sustainability while remaining profitable as costs driving production continue to rise. Compaction For most of us, compaction is the result of exerting downward force onto the soil to the point of reducing the pore space and pressing soil particles tightly together generally, but not limited to heavy machine traffic. This effect is exacerbated by trafficking the soil at its plastic limit (nearing field moisture capacity). Consequences As a result of compacting the soil, particularly in the top 30-40cm of the soil profile, infiltration and drainage is reduced, aeration is lost, soil strength increases reducing the ability of plant roots to penetrate the soil profile (Antille et al., 2016). In effect reducing the available bucket of water and nutrition for our crops to grow. After checking behind pickers and assessing some of the common practices undertaken following harvest with deep rippers and center busters, the soil doesn’t look pretty. Aggregate sizes are large (10-30cm diameter), very hard and cakey. Rippers to a depth of 40cm have pulled smeared slabs of soil to the surface, questioning how effective this method of compaction reduction is given the
Twin Row Tillage Radish Barley Cover Crop
option is possible and potentially more feasible in a zero to minimum- tillage farming system it has a harder task of being implemented into the irrigation farming systems due to cost and management practices undertaken. Mechanical cultivation through deep ripping to depths of 40-60cm, seems to be the choice when it comes to irrigation farming for most growers, however, is this process while giving short term gain leading to a bigger issue into the future by reducing aggregation, damaging the microbiology within and increasing soil strength. Should a biological pathway be taken, growing rotational crops of varying species with different rooting structures, abilities to penetrate the changing soil strength. While providing the added benefit of changing and increasing the micro/ macro biology of our soil types for example the use of Canola, Faba beans, wheat, barley, sorghum and maize, to better manage compaction. As seasons present themselves more growers are starting to have the discussion about shifting towards growing cover crops whether it be single or mixed species. Over the last few years mixing tillage radish with barley and planting it in twin rows (200mm either side of the plant line for the coming summer cotton crop)
Alleviation Possibilities
Our soils have the amazing ability to naturally ameliorate themselves given time and appropriate weather through shrinking and swelling as they go through wetting and drying cycles. However, these 2 external factors as we all know are currently the most limiting in our farming systems. Reports show that severe compaction issues can naturally ameliorate over a 5 year period, however in a irrigated- intensive farming system, practices, time and economics make this a rare possibility. So, what are some of the possible options to aid us in reducing the impact soil compaction is having on its health? Control Traffic Farming (CTF) has a good adoption rate through the dryland farming systems within Australia, proving to be effective in limiting compaction to a smaller proportion of our farming land to increase productivity of the un- trafficked areas. However, while this
Made with FlippingBook - Online Brochure Maker