Newsletter - Oct 2009

Pasture growth for month of August was a pleasant surprise after the very slow growth of June and July.

Growth rates in kgDM/ha/day from the ESI monitor property near Edgecumbe.

                      2008                  2009                     

June                25.5                     9.9                               
July                 22.6                   15.3            
August            27.7                   42.4

No nitrogen fertiliser has been applied during winter.  Milk solid production at the recent herd test was 2.65kgMS/cow, with a stocking rate of 3 cows per hectare.  With strong growth in September, albeit it somewhat stop/start due to a number of frosts, all stock have enjoyed a plentiful supply of pasture particularly during the last three weeks.

Brix levels have fluctuated, with levels as low as 8 recorded in wet cold conditions, and 14 recorded in bright sunlight conditions.  Highest levels have been recorded around mid afternoon, and are lowest early morning.

Brix levels of clover are at present sometimes higher than grasses but not always.  Regular use of the refactometer further reinforces the observation that animals have a preference for the highest energy feed in colder periods.  In bright sunny conditions where animals are fully fed on high brix pastures high-energy supplements are sometimes ignored in favour of pasture.

Brix levels of 20 –25 on pasture silage have been recorded over winter and spring on ESI properties. Where this has been higher than the maize silage also offered cows have shown a preference for the grass silage.

The higher brix levels of silage compared to pasture is largely due to wilting prior to harvest.   Maturity at time of harvest will also have an effect.  Once seed head formation begins early in November growth slows markedly with an increase in fibre and energy.

The time of cutting also has an effect, and this may be significant however more work needs to be done to ascertain just how much of an effect.   Those with good memories recall that it was always recommended that hay and silage crops were best when cut in the afternoon.

Ways of maintaining pasture quality from November onwards have been and will continue to be widely discussed.  An observation that is continually being kept in mind is that on farms with excellent soil structures strong biology and adequate nutrient levels even relatively long pasture remains suitable for top production, whether for general growth or milk solid production.

This may be because CalciZest provides the extra calcium and grunt required for strong clover growth and pastures with high clover content will have higher brix, more calcium, and less slow-to-digest fibre.

It has been interesting to note the response to summer rainfall on our monitor properties as well as general feedback from customers.  There is plenty of information to show that soils with higher humus content are able to retain more moisture. 

Farms on ESI programmes respond rapidly and strongly to summer rainfall.  With long-term trial work on nitrate interception due to start, response to summer rainfall may be something that can also be included.  Getting the numbers to support observations is helpful and may convince those that are sceptical of the premise that best pasture performance over a twelve-month period is provided by soils with excellent physical structures.

We have received information from a number of sources over time that beneficial biological activity is capable of breaking up deep pans in soils.  We were sceptical!  The purchase of a penetrometer and feedback from clients indicates that the biology introduced in CalciZest and DoloZest does over time break up hard pans.

What has been observed on properties with pans is that ponding after heavy rain steadily decreases.  Significant softening of hard layers often as deep as 350ml is apparent by
Year 4.

The short answer to the frequently asked question “why are you introducing fungi and bacteria into the soil when they are already full of microbes?” is, because they speed the process of humus formation and higher levels of humus provide increased levels of production.

The microbes introduced are selected for a range of purposes and provided by a number of suppliers that specialise in microbe production and supply. These microbes are then cultured onto soft carbon and provided with food and energy to ensure soil colonisation. 

It’s not new technology and is constantly being developed.  Those familiar with septic tanks and have had experience with microbes that can be added know how effective they can be particularly where drain fields are a little blocked.

Baches that were infrequently used and then subject to large number of people over Christmas and New Year often suffered septic tank malfunction because the natural supply of the digesting microbes didn’t keep pace.

Microbes are used in calf rearing, silage making, cheese, beer, and bread making.  Soil is a big digester and the addition of microbes speeds the break down of roots, dung, leaf, and other material, increasing the rate at which humus is formed.

Azotobacter are also introduced in DoloZest and CalciZest.  Azotobacter fix plant available nitrogen without the need for legumes and there is information to suggest that the amount may be significant.

Altering and maintaining the environment that favours the introduced microbes is important.  Constant levels of plant available soil calcium favour beneficial microbes as well as earthworm activity and numbers.  This is one of the reasons for ESI programmes recommending regular calcium inputs along with phosphorus, sulphur, and potassium as required. 

Observation is the most powerful tool farmers have.  Trial work confirms what farmers observe and allows measures to be obtained and a better understanding of why things occur which in turn helps with predicting future growth and production patterns.