Healthy soils need plenty of air
SOIL fertility is generally held to be the most significant factor in maximising pasture and crop growth.
For years we have done tests that are designed to establish the PH levels and if there are any deficiencies in essential mineral levels in the soil, and if so, apply the appropriate fertilisers to correct these. But with the recent increase in fertiliser prices and lack of availability, alternative methods may be needed to keep improving soil fertility.
One way can be the use of aerators to loosen compacted soils, allowing oxygen to enter the soil and can unlock these nutrients that are retained in the soils.
The limitation of the oxygen supply to soils has a direct effect on plants and a severe effect on the myriad of micro and macro soil organisms that are essential in establishing and maintaining a healthy and productive soils. A sure sign of compaction is the root system of the plants. In compacted soils the plant roots tend to grow sideways, so growth will be limited by intensive competition for and less availability of soil moisture and nutrients. Plants will also tend to have their crowns higher out of the ground, so they are more susceptible to damage from grazing and treading. Autumn ‘pulling’ of rye grass will also be more of a problem. Greater depth of root structure will give a greater ability to produce grass growth during dry times and will unlock nutrients retained in the soil.
Also aeration can be good to improve pastures that are starting to drop their growth rates but still have a good grass base to work with. Aeration can release lock-up nutrients and allow the root system to redevelop without the expensive and time out of action of a full pasture renovation.
Another sign of compacted soils is the inner ability of the soil to absorb moisture from the recent rains. If the ground is showing signs of water logging with water remaining to the top of the surface, aeration will greatly benefit the soils ability to absorb moisture and then allow the plants root system to utilise this moisture during the summer months.
Soil structure can easily be checked by visual inspection. With a spade, dig out a block of soil to the dimensions of 20cm x 20cm x 25cm deep. If there is a clear line between a profusion of roots at the top of the soil block in a dark crumbly soil, and then a lower layer of hard, dense packed looking soil, the soil structure is poor.
A good soil structure and a healthy worm population go hand in hand. Earthworms are a good indicator of the soils biological status. In a well structured, healthy and fertile soil there should be more than 20 worms in every spade sample. If there is less than 10, there is a good chance there is a problem with the soil structure and the quickest and easiest solution is likely to be mechanical aeration or tined rippers to improve this soil structure.
During the late winter and early spring months is the best time for aeration. When there is enough moisture in the soil to allow aerators to penetrate and break up the hard pan of sub soil below the root system, lift and loosen the top soil and allow spring rains to absorb and retain into the soil.
James Engineering in New Zealand has been developing, testing and working with farmers for over 30 years in the development of aerators to improve soil structure. Their new series of aerators feature fine shank tines with individual coulters fitted for minimal top surface disturbance. Tyne spacing and shape, designed to break up and loosen the hard pan and compacted soils underneath. Two types of models are available with both shear bolt protection or new style auto reset tines are available for grounds with rocks or stumpy conditions.
Mike Keys from James Engineering says it is more ever important to get the most out of your pastures. With the ever increasing costs of fertilisers and the costs of renovating your pasture, aeration can be a more cost effective alterative. Aeration can improve soil structure, assist in unlocking soil fertility and improve root development of pastures for greater ability to produce grass.
TracMac Farm Equipment will be displaying the range of James aerator on their stand CB126 at Farm World 2016 or you can contact us on 5625 1522 or 0418 515510.