Waikato-based Soil Scientist Gordon Rajendram PhD is considered one of New Zealand’s experts in soil fertility. He is committed to helping New Zealand farmers get the most out of their soil so that their farm can work more proficiently, be sustainable while still increasing the farm profitability. Dr. Gordon Rajendram worked at AgResearch, Ruakura Research Centre, Hamilton. He has developed two field calibrated soil tests (N & S) which are used for agronomic advice in NZ and his work on leaching has been included in the Overseer nutrient model.
A lot of farms in New Zealand’s Hill Country have alarmingly low pH soil levels. There has been more emphasis on fertiliser at the expense of liming. However, both can be achieved within the farmers budget if a long-term plan is put in place says leading Hamilton-based Soil Scientist Dr Gordon Rajendram (PhD).
Gordon says that generally pasture species do not like low pH soils as there is increased Aluminium in the soil solution which retards root growth, which in turn leads to less growth of herbage on top.
MAF’s recommendation is for soil pH to be between 5.8 and 6.0 based on the dry matter production. “The ideal pH is around 6.2 if you take into account quality of feed, more clover growth, greater earth worms (which aerates the soil), more calcium in the diet, and phosphate less tightly held by the soil,” comments Gordon.
Because of the cost of flying lime on Hill Country, a lot of farmers are put off from trying it. Lime is normally $20 - $35 per tonne, cartage is typically ~$20 -30 per tonne, but flying is ~$120/tonne. “There is not enough in the farmers’ budget when normal hill country farm fertiliser and lime budget is ~130/hectare/per year,” says Gordon.
Normally it takes 1 tonne of lime to lift soil pH by 0.1 unit, but it much depends on the Cation exchange capacity (CEC) of the soil. A low CEC soil, such as a sandy soil, requires much less lime to lift pH by 0.1 unit.
The problem with New Zealand farms is that farmers are not applying lime because of the above, so many soils are getting very acidic (< 5.5 pH), with soils getting down to as low as 5.0 pH. This has a significant detrimental impact on pasture production and clover growth, which ultimately leads to animal performance.
The solution lies in having proper soil and pasture testing as without testing you cannot know what minerals needed to be added to your soil and in what amounts. Otherwise it becomes a guessing game. Expert advice is needed at the right time, with a plan to address the issue within the budget allocated.
If these steps are taken, there is enough in the farmers budget to both lime and fertilise to reduce soil acidification.
About The Soil Scientist
Gordon is dedicated to helping all farmers get most out of their soil so that their farm can work more efficiently, be sustainable while improving the farm profitability.
Phone: 021 466 077
Phone: 0274 587 724