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In the pursuit of sustainable agricultural practices, Dr. Gordon Rajendram, a Hamilton-based soil scientist, in collaboration with Agraforum of Ashburton, introduces EL-I Tech’s Biodynamic Nitrogen (Bio N) as a groundbreaking biological approach to address nitrogen deficiency in New Zealand soils. This innovative approach to nitrogen fixation, pioneered in South Africa by Gerhard Vermaak and dubbed EL-I Tech involves the application of microbes and substrate through foliar spraying, facilitating the biological fixation of nitrogen from the atmosphere for plant utilisation. The trials, conducted in collaboration with Agraforum, took place on three dairy farms in mid-Canterbury from early November 2023 to the end of January 2024, spanning a 12-week period. The comprehensive study aimed to evaluate the efficacy of Bio N in comparison to traditional synthetic nitrogen (urea), focusing on pasture growth, cost-effectiveness, and environmental impact. On Eiffleton farm, where both Bio N and Urea were applied, Dr. Gordon Rajendram observed that Bio N exhibited comparable daily growth rates to Urea over a 9-week period. Moreover, the total pasture produced using Bio N slightly surpassed that of Urea, demonstrating its effectiveness in sustaining pasture growth. Farm 1: Eiffleton farm Table 1c: Total pasture produced over a 63-day period (kg dry matter/hectare) Bio N (kg DM/hectare) Urea (kg DM/hectare) 5103 4977 Similarly, on Farm 2 Maronan farm, Bio N, applied only once on 8th November 2023, demonstrated competitive growth rates with Urea over an 11-week period. The total pasture produced with Bio N exceeded that of Urea, showcasing its potential for cost-effective pasture management. Farm 2: Maronan Farm Table 2c: Total pasture produced over a 77-day period (kg dry matter/hectare) Time Bio N (kg DM/hectare) Urea (kg DM/hectare) 77 days 6160 5698 On the Alford Forest Area farm, where Bio N was applied only once on 27th November 2023, the results were consistent. Bio N offered comparable growth rates and kept a consistent total pasture production alongside Urea over 8 weeks. Farm 3: Alford Forest Area Table 3c: Total pasture produced over a 64-day period (kg dry matter/hectare) Time Bio N (kg DM/hectare) Urea (kg DM/hectare) 64 days 3712 3968 The collaborative efforts of Dr. Gordon Rajendram and Agraforum underscore that Bio N not only matches Urea in pasture growth but also requires only one application compared to multiple rounds of Urea. Additionally, the cost of producing pasture with Bio N is lower than that of Urea, making it an economically viable alternative. The potential environmental benefits, such as reduced greenhouse gas emissions and carbon footprint, are acknowledged, although further research is needed for a comprehensive evaluation. In conclusion, EL-I Tech, presented by Dr. Gordon Rajendram and Agraforum, Biodynamic Nitrogen emerges as a promising biological solution for overcoming nitrogen deficiency in New Zealand soils, providing sustainable and cost-effective alternatives to traditional synthetic nitrogen applications. Photo: “Bio N applied on this pasture.  Visually, Where Bio N is applied in paddocks, I found the pasture cover over the paddock is very uniform. i.e. urine patches did not stick out.” – Dr Gordon Rajendram Contact Agraforum 0800 488 118 allan@agraforum.co.nz www.agraforum.co.nz/contact-us Contact Dr Gordon Rajendram 021 466077 rajendram@xtra.co.nz www.gordonrajendramsoilscientist.co.nz Contact Phillip Quay 027 458 7724 phillip@mediapa.co.nz www.mediapa.co.nz

Healthy soil and pasture production rely upon the correct soil testing process. Let’s take a look at two key factors that drive pasture production. The first key factor is soil temperature at 10cm. At 5 or 6 degrees, the pasture stops growing. The second key factor is soil moisture and the significant impact on pasture production with soil moisture < 25%. A Field Collaborated Soil Test at this stage will help you find the maximum pasture production between low productivity and wasting money. At this point, I would like to highlight that pasture species do not thrive in low-pH soils in addition to the two critical factors named above. Why is this? In simple terms, it is due to the increased Aluminium in the soil solution, which retards root growth – the implication leading to less growth of herbage on top. Currently, many soils are very acidic (<5.5pH). Farmers could alleviate this problem by applying lime to eliminate soil acidity. However, with the proper testing and planning, every budget has room to include lime and fertiliser as part of pasture management programmes. You may have heard in the news recently about the impact Leaching is having on our soils.  Leaching is the loss of water-soluble plant nutrients from soils. Factors such as rain and irrigation are contributing factors. The result – amounts of nutrients are lost via sub-service flow related to the amount of rainfall and drainage.  We see the knock-on effect with essential nutrients in plants. These exist as anions and cations – the leaching of anions and cations is conditional on various factors including, but not limited to, the amounts and form of nutrients applied in fertiliser, stocking rates, drainage, soil types and the previous extent of soil leaching. Plant growth is dependent on a critical element – Phosphate. Applied phosphate must remain in the soil and not run off as particulate P or leach into subsoils.  So how can we mitigate P losses? . I want to emphasise two critical factors. I cannot stress enough the importance of this information when factoring in using phosphorus and sulphur fertilisers. Secondly, it is essential to remember that fertiliser is only one aspect of a productive management system. If you don’t test properly, you are doing yourself a disservice to your business. As an Independent Fertiliser Consultant, I am dedicated to helping all farmers get the most out of their soils so their farm, their most significant asset, works more efficiently and sustainably for increased profitability. “To forget how to dig the earth and to tend the soil is to forget ourselves.” -Mahatma Gandhi. Dr Gordon Rajendram is a New Zealand Independent Soil Scientist specialising in Soil Fertility, Agronomy & Farm Environmental Consultancy.

With the high fertiliser prices this year it will be prudent to soil test, in particular to measure soil pH, and correct deficiencies by liming as lime prices have stayed relatively similar to last year. A lot of farms in New Zealand’s Hill Country have low soil pH levels. Dairy pastures that do not perform are usually associated with low soil pH.  As it stands, there has been more emphasis on fertiliser at the expense of liming. However, both can be achieved within the farmer’s budget. 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. Soil pH levels below 5.5 tend to have soil solution Aluminium levels >3.0 mg/kg, ideally you want the aluminium levels < 0.1 mg/kg. One of the cheapest ways to alleviate this issue is liming.   There is scientific evidence to show that as soil pH increases up to ~soil pH 6.5 there is an increase in microbial activity.  Microbial activity plays a major role in nutrient cycling in the soil.  You may have 3 (500 kg) cattle running on top of your dirt, but you have about the equivalent (in weight) of 25 cattle or 250 sheep, in underground fauna, running below ground. 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 – 6.4 if you consider quality of feed, more clover growth, greater earth worms (which aerate the soil), more calcium in the diet, and phosphate less tightly held by the soil. Because of the cost of flying lime on Hill Country, a lot of farmers are put off from trying it. Lime is normally $30 -$35 per tonne, cartage is typically ~$20 – 40 per tonne (depending on how far the farm is from the lime pit), but flying is ~$120/tonne.  There is not enough in the farmers’ budget when a normal Hill Country farm fertiliser and lime budget is ~$120 -$150 /hectare/per year. However, there are solutions to address this price issue. Normally it takes 1 tonne of lime to lift soil pH by 0.1 unit, but 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. With the greater rainfall this spring there will be greater leaching occurring and soil nitrates that leach below the root zone will take a positive ion such as calcium with it.  Generally, ~150 kg/ha/yr of Calcium is leached if no nitrogen is applied as fertiliser but increases as more nitrogen fertiliser is applied. 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 substandard animal performance. The solution lies in having proper soil and pasture testing as without testing you cannot know what minerals need 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 in order to reduce soil acidification. 

Soil porosity is a measure of air space in the soil and macroporosity is a measure of the proportion of large pores in the soil that provide air supply to roots and microbes. Soils that have been compacted because of animal treading or machinery have poor macroporosity levels. This is like a foot on an individual’s throat, and they are saying they can’t breathe. It’s the same scenario for plants and microbes. Ag Research soil scientist Dr Peter Singleton and his team based at Ruakura Research centre, Hamilton, in the late 1990s found that a 10% macroporosity level in soils was a critical value in relation to pasture and crop production. It’s a useful soil physical field calibrated test developed for New Zealand soils. His research team found that there was a 10 % decrease in pasture production for every 1% decrease in macroporosity below the critical level of 10 %. Depending on the soil type, treading and compaction damage can reduce pasture production by up to 50% or more and take 6 months to 1 year to return to normal pasture production levels. When soil structure is damaged, the infiltration rate decreases and pores that are required for aeration and drainage are destroyed. Other issues include ~80% decrease in worm populations, increased runoff of water, sediment and faecal coliforms, reduction of phosphate and other nutrient uptake and increased greenhouse gases. It can also affect soil temperature and plant root penetration. An excellent illustration of compaction and soil aeration was evident on a sheep and beef farm I visited near Te Kuiti. In a 30 meter by several hundred-meter strip in a paddock upon a hill, there was amazing pasture growth. This patch had approximately 2500 pasture cover but on either side of the 30 meter strip the cover would have been less than halve. The difference was obvious. The reason for the extra pasture growth was that a trench had been dug for a water pipe and when the soil had been returned it was in a less compacted state. As another example, I advised a young dairy farmer near Putaruru to aerate his paddock with a James aerator. The soil type was volcanic silt loam. He said the difference after aerating the paddock was incredible as the pasture growth difference to the next paddock where he did not aerate was phenomenal. There are many ways you can aerate a soil. You can do it chemically by using lime or gypsum, biologically by adding compost/organic matter, encouraging earthworms (by liming), and microbes & fungi or mechanically with a tractor and equipment such as a James aerator, ground hog, Rata and numerous other brands’ including a Forbes soil conditioner. Having drains can also reduce compaction by draining soils in wet periods of the year which will reduce compaction. About 2 months ago I was introduced to Stu Forbes by a mutual friend. Stu had developed his Forbes soil conditioner/aerator over a 35-year period with a team, including Prof. John Baker. Stu reckons he has got the best piece of equipment to aerate soils with. But he is always challenged by ‘show me the data’. That’s where I come in, as I see soil aeration/soil structure to be just as important, as soil moisture (by rainfall or irrigation) and soil pH and nutrients. Stu and I have therefore commenced trials on sheep/beef and dairy farms using the Forbes soil conditioner. The trial will be carried out on many farms around New Zealand, from as far north as Northland to Wairarapa, and in Canterbury. Pasture production will be monitored with and without the use of the soil conditioner.

The leaching of nutrients in soils generally occurs between the months of April – October, and there is a lot going on below ground, more than we imagine. This article explores the effect of rate of nitrogen fertiliser on cation and anion leaching under intensively grazed dairy pasture which can have far reaching effects on the way we farm from Hamilton-based Soil Scientist Dr Gordon Rajendram (PhD). In New Zealand, there have been limited studies on the topic of leaching of anions and cations in intensive New Zealand dairy farming systems. However, it is an important topic, as it is vital to the soil health and long-term effects on New Zealand farms. Leaching is the loss of water-soluble plant nutrients from the soil, due to rain and irrigation. Plant essential nutrients exist as anions and cations. Anions are elements or molecules that in their natural state have a negative (-) charge. Cations are ones that have a positive (+) charge in their natural state. Generally, soil is negatively charged and repels negative ions (anions), which are easily leached by rainwater and irrigation drainage.  Negative ions which are leached take a positive ion with it, it is part of nature. “The leaching of anions and cations is conditional on various factors including the amounts and form of nutrients applied in fertiliser, stocking rate, rainfall & therefore drainage, soil type and extent of previous leaching,” says the Soil Scientist Dr Gordon Rajendram The increased use of nitrogen fertiliser on dairy farms for the last few decades, has led to the growing concern about the effect on nitrate leaching to groundwater. A study in the mid 1990’s by Rajendram and Stewart Ledgard and other research’s at AgResearch set out to determine the amounts of Ca, Mg, Na, K, nitrate-N, sulphate-S, Cl and inorganic P leached from intensively grazed dairy pasture at three sites (Waikato, Taranaki & Southland) over a five-year period in the absence of N. In addition, nutrient leaching was determined in dairy farmlets at the three sites receiving 0, 200 or 400 kg N/ha/year. “The quantities of cations and anions leached from the farmlets getting no nitrogen fertiliser represented a significant removal of these nutrients from the system, particularly under high drainage,” comments Gordon. Where no N was applied, approximately $240 of fertiliser was applied above ground, but $160 of nutrients was lost below the root zone in drainage. Once the N applied was increased to 400 kg N/ha/yr, the value of nutrients lost below the root zone jumped to $250/ha/year. Another negative impact was, clover N fixation decreased from 180 to 0 kg/N/year when nitrogen application rates increased from zero N applied to 400 kg N applied per hectare per year. Leaching losses for cations and anions were similar between the different non-N-fertilised farmlets even though there were differences in soil drainage characteristics, region and management practices. This study showed that high-level leaching losses of Ca, Mg, Na, nitrate-N, sulphate-S and Cl occurred from intensively grazed pasture and that heightened farming intensity, through the use of N fertiliser, increased the losses of Ca and nitrate-N. Soil Magnesium levels were decreasing on farms in the 1980’s and 90’s. This study showed the reason why this was the case.  Approximately 30 kg per hectare of magnesium was being leached every year and not replaced in fertiliser or via rainfall. “These results have significant consequences to the sustainability of these systems, the potential for an increase in the incidence of hypocalcaemia and hypomagnesaemia in animals, and the requirements for nutrient inputs in fertilisers,” advises Gordon.  The research findings were included into the Overseer nutrient model. When farmers are required to determine their N leaching index, cations and anions leached is also generated by Overseer as part of the output. Waikato based Soil Scientist Gordon Rajendram 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 increasing farm profitability. Gordon is one of the leading voices in soil fertility.

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. Soils will continue to change over time, that’s why regular soil testing is crucial to the continued health and success of your farm says Hamilton-based leading Soil Scientist Dr Gordon Rajendram (PhD). Soil testing will showcase the mineral imbalances that may be affecting the health of your crops or livestock. Macroporosity is a measure of the proportion of large pores in the soil that provide the air supply to roots and microbes. A 10 % decrease in pasture production for every 1% decrease in microporosity below the critical level of 10 %. It’s the best soil physical field calibrated test for New Zealand and was developed by AgResearch in the late 1990’s.   Treading damage can cost loss in pasture production. “When soil structure is damaged the infiltration, rate decreases and pores that are required for aeration and drainage are destroyed,” says Gordon. Other issues are ~80% decrease in worm populations, Increased runoff of water, sediment, faecal coliforms, phosphate and other nutrients plus Increased greenhouse gases. An ASC test (Anion Storage Capacity), previously known as P Retention, is a measure used to define the phosphorus (P) immobilisation potential of a soil. This will test the ability of the soil to hold on to phosphate and sulphur.   An ASC test must be included with every sampled area to determine its level. “This is particularly valuable information when bearing in mind the use of phosphorus and sulphur fertilisers,” adds Gordon.  Low ASC soils have minimal P binding sites. Once you have all the testing done, and have all the accurate information on what needs to go on your soil, the next step is to develop a fertiliser programme specific to each area or paddock. Fine particle or slow-release fertiliser is a great choice. Fine particle fertiliser has improved fertiliser use efficiency with lower spread rates required to get the most out of it. “Featuring a rapid uptake of needed nutrients, with fine particle fertiliser deficiencies can be rectified quickly due to the excellent foliar nutrient uptake,” adds Gordon. With efficient application the proportion of nutrients can be varied. Not only that, it also has reduced environmental impact. You may not be able to change your soil type or the climate, but you can control the amount and type of phosphorus and sulphur that are applied to vulnerable areas. If you want to discover more about the benefits of soil testing can bring to your farm, then make sure you get the best in New Zealand, the soil scientist Dr Gordon Rajendram out to your rural farm today.  With his BSc, MSc and a PhD, Gordon is one of the leading experts on laboratory and field measurement techniques for chemical, biological and physical properties. 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. Contact Gordon: Email: rajendram@xtra.co.nz Phone: 021 466 077 Facebook: https://www.facebook.com/GordonRajendramSoilScientist Website: http://dev.gordonrajendramsoilscientist.co.nz LinkedIn: https://www.linkedin.com/company/the-soil-scientist Instagram: https://www.instagram.com/thesoilscientistnz/ Contact MediaPA: Phone: 0274 587 724 Email: phillip@mediapa.co.nz Website: www.mediapa.co.nz Facebook: www.facebook.com/MediaPA YouTube: www.youtube.com/user/TheMediaPA

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. In this second article I further explore the above question, which is better liquid, suspension, or granular fertiliser? This year the farming industry has seen unprecedented price rises for two of the major nutrients required for pasture and crop growth, phosphate, and nitrogen. The price of phosphate has increased from $2.70 to $4.27 for a kilo of the nutrient, and likewise nitrogen has increased from $1.15 to $2.89. Other nutrients such as sulphur ($0.60 to $0.90 per kilo of S), potassium and trace elements have also increased appreciably.  Due to the increase in fertiliser costs farmers are faced with keeping pasture or crop production at similar or higher levels. They will look to solutions, methodology or technologies which will be more nutrient efficient. i.e., get more pasture response with less nutrient use.    In this article I will concentrate more on my experiences with technologies/methodology which may achieve the above goal.  In the 22 years I worked at MAF and its predecessor AgResearch, Ruakura Research Centre in Hamilton, the products we researched were generally all granular based.  We did Government funded research or did projects for companies who could afford us and there weren’t many of these companies in New Zealand.  In 2016 I gave a talk in the Far North, near Taipa, to a group of farmers. At question time one of the farmers sitting in the front asked me, what I thought of fine particle application (FPA)? FPA is a trade name, but I call it suspension technology. I told him I knew nothing about it.  After the talk I approached him and asked if I could visit his farm to see what he meant as I wanted to know more.  The farmer was Arthur Beazley who runs red devon cattle on a 120ha farm just north of Kaeo. I visited him the next day and he showed me his tow n fert machine. Therefore, this started me on my journey of learning about suspension technology and foliar/liquid fertilisers.  Suspension technology uses finely ground nutrients. There are companies in New Zealand who have specialised in this technology for more than 30 years. Companies such as Uptake,  based in Taupo owned by John Davis, Mainfert, based in Timaru owned by Marty Kimble and Dean White, and there are others as well who specialise in this technology in New Zealand. Suspension technology requires specialised ground-based equipment such as the tow n fert machine (Metalform in Dannevirke) or Cylone mixers (Chaos farming in Waihi). These machines require robust pumps and large nozzles. The ground up nutrients are very abrasive and therefore require specialised equipment. There are helicopter operators and SuperAir who have the equipment to apply it from the air.  Therefore 16 elements (or more), fine lime, including growth promotors, inhibitors, hard round seeds like clover, fungicides or insecticides can be applied together.  Suspensions are in between liquid and granular and are ground up nutrients, and rates of application of a nutrient per hectare can be as high as granular if required. So, how can these technologies be more efficient and cost-effective? These questions will be answered in the following series of articles.

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 and be sustainable while still increasing farm profitability. Dr Gordon Rajendram formerly worked at AgResearch, Ruakura Research Centre, Hamilton.  He has developed two fields of calibrated soil tests (N & S) which are used for agronomic advice in New Zealand and his industry-leading work on leaching has been included in the Overseer nutrient model. Due to the increase in fertiliser costs, farmers are faced with keeping pasture or crop production at similar or higher levels with similar fertiliser budgets to previously.  Can we, therefore, keep the same fertiliser spend as previously and grow just as much nutritious pasture or more pasture without compromising production or have any detrimental effects to the environment? This will be the first of a series of articles in which I explore the above question.  Firstly the main factors which drive pasture production are soil moisture, temperature, approximately 13 soil nutrients, soil acidity, microbiology and finally but not least soil air space (soil porosity).   The mantra I constantly use “if you don’t test, you cannot manage”.  It is very important to test soil, pasture, clover only and individual crops to see if any of the above factors are limiting growth.  All these parameters have optimum limits for pasture or crop growth and will be limited if these are not in the target areas. For the 13 nutrients,  once the optimum levels are reached, only maintenance rates are required and therefore application rates can be low depending on the nutrient, soil type and climatic factors (leaching and runoff).  Monitoring of pasture growth rates is also a very important testing tool. In the last five years, I have had experiences with technologies that I believe can be part of achieving the above. In this article, I will concentrate more on my experiences with these technologies whereas in the next articles I will dwell more on the science. The majority of fertilisers in New Zealand are applied in a solid granulated form for ease of spreading and generally are a in a highly soluble form i.e., becomes quickly available to pasture or crops. There are benefits to this but once optimum nutrient levels are achieved are there better technologies/modes of application available?  Suspension technology, or otherwise known as fine particle application or foliar/liquid,  may be more efficient and cost effective.  Soluble liquid fertilisers can be applied with normal spray equipment but with suspensions require specialised equipment with robust pumps and larger nozzles.   With liquids and suspensions up to 16 elements (13 for pasture growth plus three more for animal health) can be applied in one application, including growth promotors, inhibitors and fungicides or insecticides.  Suspensions are in between liquid and granular and are ground up fertilisers/nutrients and rate of application can be as high as granular if required. So, how can these technologies be more efficient and cost-effective? These questions will be answered in following articles.