Category Archives: Irrigation

Sweetcorn Harvested

CornHarvest20140410_124642

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Many thanks to McCain Foods, Te Mata Contractors, Apatu Farms and Heinz-Watties for help harvesting our corn crop.

Given the wet week we were pleased to have a break in the weather and fortunate the soil was not excessively wet. Gross weight out was around 20 t/ha which, given we suffered a fair bit from drought stress is pleasing.

Ben Watson and Dan Bloomer took crop samples from both Paddocks (3 & 4) and from drip irrigated, spray irrigated and non-irrigated zones. We’ll be interested to see the results.

Next activity is a full deep ripping to at least 600mm to try and address the deep compaction we have identified. Regional Council soil health sampling, HydroServices data and our own digging shows a legacy from previous land use remains – despite seven years of pasture phase and minimal traffic. We have ripped before, but only to about 300 – 400mm.

After that we’ll be establishing our winter crops – selected from onions, oats and mustard cover crops.

Playing with Peas

At the LandWISE MicroFarm, we are scoping the use of plant growth regulators to lift yields of peas for processing.

In our region, peas are produced for the global market, and the global price sets the local price. You’ll struggle to find a farmer that says the pay-out is generous. We could focus on increasing the price by $5 a tonne or even $50 a tonne. But that will make us uncompetitive. 

So how can we make it a profitable crop?

We could cut costs, though there is little left to remove. Peas don’t usually get fertiliser or slug bait, insecticides or disease sprays. Most get little or no cultivation. They do get herbicide treatment, but many chemicals are relatively cheap.

What’s left?

“Yield is king!” say LandWISE farmers. 

The yields of many crops have increased enormously over the last twenty years.  Pea yields have not, and are highly variable and unpredictable.  Even in good looking crops, yield can be disappointing.

As with any one pass harvest fresh vegetable crop, top yields need good plant, pod and seed numbers, all ready for harvest at the same time. Sometimes parts of a paddock are behind, sometimes parts of plants are left behind.

If part of a paddock matures differently, it is often because the plants emerged at different times. The cause may be soil moisture or temperature differences. Maybe it is compaction related.

If some plants mature at different rates it may be sowing or soil conditions causing uneven emergence.

If some pods mature at different times, maybe flowering was prolonged. If we condense flowering, all the plant’s resources go into peas that get harvested.

Farmers have noted drought-stressed crops can out-yield more vigorous ones. The stressed plants seem to have flowering curtailed, while vigorous ones continue flowering and have late pods and peas that will not be mature at harvest.

The MicroFarm group is looking at plant growth regulators to condense flowering and therefore the harvestable proportion of the crop.

Plant growth regulators control things such as shoot and root growth, internode length, flowering, fruit set and ripening. They are widely used in horticulture and have been used to manipulate flowering times.

We are applying a few options that have shown to have effect elsewhere. It is a first look to see if this is something worth researching further.

Our Discussion Group members’ experience has been brought together to formulate our “grand plan”.

Five different PGR products are being applied to the crop at different growth stages. The PGR’s include gibberellic acid, anti-gibberellin (Cycocel 750, Regalis), cytokinin (Exilis) and anti-ethylene (ReTain). These are potentially potent materials: one of our treatments is 8 grams per hectare.

The treatments are being applied in 3m x 10m strips, but are not being replicated in this initial scoping study. We do however have two sowings so we will get a couple of chances to compare. We will observe effects and yields. If we see evidence of a benefit, we will do a more detailed study.

Gibberellic acid was applied when peas were 10-15cm high. A rapid lengthening and yellowing of treated plants was quickly seen. The yellowing has reduced in time, but the plants are still double the height of their untreated neighbours.

But it is flowering we are interested in and that is still just around the corner. We have noted two flowers in one treated plant, and none elsewhere in the paddock.

The next set of treatments was applied about 10 days before anticipated flowering date. We are watching things closely.

Many thanks to the people involved in formulating the plan, and now implementing it: Plant Growth Regulators were supplied by BASF Crop Protection, Agronica and Fruitfed Supplies. Treatments were applied by Peracto. Plant & Food are monitoring the effects.

PGRSponsors

A report of results of the season’s PGR trials is posted on the MicroFarm website.

MicroFarm Open Day 3-5pm 2 April 2014

Ballance web150  BASF web  CLAW-light-150

The second MicroFarm Open Day date will focus on beans, sweetcorn and water management.

Bean planting P6 Airey 3 web

Bean planting – Richard Airey picture

The green beans are destined for McCain Foods Hastings plant. The four micropaddocks include demonstrations of:

  • Two row spacings 20″ and 15″
  • Four plant populations
  • Different varieties
  • Drip vs spray irrigation
  • Phosphorus: non vs normal vs double rate
  • Herbicide management variations

Sweetcorn demonstrations

  • Strip-till
  • No irrigation
  • Drip irrigation
  • Very late spray irrigation

Irrigation discussion

  • Soil monitoring records from 2013-2014 crops
  • Where crops are getting water from
  • Impact of drought stress
  • Cost of drought stress

More details on the MicroFarm website

Many thanks to:

Ballance AgriNutrients, BASF Crop Protection, Centre for Land and Water, ThinkWater, Netafim, HydroServices, McCain Foods, FruitFed Supplies, Agronica NZ, Nicolle Contracting, Te Mata Contractors, Drumpeel Farms, Agnew Hort, Greville Ground Spraying, True Earth Organics, Tasman Harvesting, Plant & Food Research and Peracto Research for support with this work.

Irrigation NZ Conference

INZ2014The biennial Irrigation New Zealand Conference will be held in Napier on 7-9 April 2014. This is a major event for farmers and industry with a number of high profile speakers from around the world. Details at http://irrigationnz.co.nz/events-and-training/irrigation-securing-the-next-generation-s-future/

Monday 7 April includes optional bus tours, one of irrigation on the Heretaunga Plains and one to visit the proposed Ruataniwha Irrigation Scheme and site of the water storage dam. From 2pm the trade show is open to view the latest and greatest opportunities and technologies.

Tuesday 8 and Wednesday 9 April are based at the Museum/Theatre/Gallery and War Memorial Conference Centre on Napier’s Marine Parade.

Hear

  • Rod Oram discuss Irrigation – securing the next generation’s future
  • About the catalyst for and execution of Hawke’s Bay Ruataniwha water storage project
  • If government policy is helping or hindering
  • Technology updates
  • Good practice expectations
  • and lots more

 

Irrigation: Do peas benefit? Do farmers?

At the MicroFarm, we just harvested our second lot of peas.  We tracked their water use since planting to build on learning from our first crop (see the December 2013 issue of “Grower”, reproduced here>).

Pea Harvester MicroFarm2

Once again, HydroServices’ Melanie Smith established three neutron probe access tubes in each of two crops. These were read weekly and analysed to tell us paddock soil moisture content down to 80 cm.

Both pea crops were planted on the same day with the same drill. Paddock 1 is dryland and Paddock 2 has drip irrigation installed 200mm deep.

Figures Paddock 1 and Paddock 2 show soil water content for each crop.

Paddock 1_Peas
Paddock 1_Peas

 

Paddock 2_Peas
Paddock 2_Peas

We see the crops tracked about the same at the start. In mid-December, Paddock 2 received two 9mm irrigations from our buried dripline.

Melanie estimated that the irrigation was 80% efficient, so only added about 7.5mm to the budget each time. Paddock 1 is not irrigated, and continued to drop towards stress point.

Paddock 1 reached Refill Point on Boxing Day two days before rain fortunately lifted it back out of stress. Paddock 1 again hit stress point on about 6th January. With no more significant rain, it stayed stressed. With irrigation applied as required, Paddock 2 remained stress-free throughout.

Overall, the two crops used similar amounts of water through until early January. After that the 0 – 30 cm soil reached stress point, and water use from the unirrigated Paddock 1 began to taper off.  The steeper lines in the bottom part of the graphs show it began to get more water from deeper in the profile.

By harvest, Paddock 1 was using only about half as much water as the drip irrigated Paddock 2 and drawing it from much deeper in the profile.

The difference in what a crop did use and what it could have used if the water was available is described by Potential Soil Moisture Deficit.

We estimate that by harvest, Paddock 1 suffered about 100mm of PSMD. I am not sure what the pea response is to stress. I am told it is a “very elastic” crop. For many crops this would indicate a growth reduction of about 20%.

So did irrigation pay?

We sampled each crop pre-harvest and found Paddock 2 had about 30% more fresh weight canopy than Paddock 1. The difference was easily seen, being significantly taller and generally more “lush”. The peas in Paddock 1 reached harvest maturity at least three or four days before the irrigated peas in Paddock 2.

We get paid for peas not canopy. We also sampled yields and quality as measured by TR (pea tenderness) and found differences.

There was a lower tonnage in Paddock 2, but the quality (and pay-out value) was much higher.

At harvest the Paddock 1 tonnages were reasonable at 6.85 t/ha paid yield. But TR was 137; a bit high and the lowest pay-out grade.

We delayed harvesting Paddock 2 for two days. The paid yield was similar at 6.55 t/ha but the TR was 102, a 30% higher pay-out grade.

Paddock 1 returned $2,059/ha and Paddock 2 returned $2,625/ha gross, so a benefit of $566/ha from irrigation.

We applied 81 mm so our return from irrigation was $6.99/ha/mm applied. Many people quote an irrigation cost of about $2/ha/mm so let’s claim a benefit of $5/ha/mm applied.

Looking at it another way. If we had a 20ha paddock, irrigation would have made us about $8,000 better off. If we also sold pea hay, the benefit would be even greater.

Answer: Irrigation pays!

Thanks to: Centre for Land and Water, ThinkWater, Netafim, HydroServices, McCain Foods, Ballance AgriNutrients, BASF Crop Protection, FruitFed Supplies, Agronica NZ, Nicolle Contracting, Drumpeel Farms, Greville Ground Spraying, True Earth Organics, Tasman Harvesting, Plant & Food Research, Peracto NZ

Irrigation demand: alike as two peas?

The MicroFarm has two crops of peas almost ready for harvest. We have been tracking their water use since planting. We want to learn as much as we can about our soil and irrigation.

HydroServices’ Melanie Smith is our specialist support for soil moisture monitoring. She established three neutron probe access tubes in each of our first two crops. These are read weekly and analysed to give a Paddock soil moisture content down to 80 cm.

Both pea crops were planted on the same day with the same drill. One had some nitrogen starter-fertiliser because our discussion group wondered if it would make a difference, but that is another story. For now, we are talking irrigation management.

We are seeing significantly different patterns from our two crops. Significant in that considering the usual 30 cm root depth, one crop needed irrigating a week before the other. Significant in that one would get through to harvest at the start of December without needing to be irrigated. The other would need irrigation. What’s going on?

Let’s look at two graphs: Paddock 3a and Paddock 4a which are the two crops in question.

Paddock_3_a
Paddock_3_a
Paddock_4_a
Paddock_4_a

 

 

 

 

The top parts of these graphs show soil water content in the top 30 cm. We see that in each case the Full Point (116 mm) and Refill Point (82 mm) is the same. So we have 34 mm of readily available water our plants can access from the first 30 cm depth of soil.

The graphs show Paddock 4 reached Refill Point a whole week before Paddock 3. In fact, Paddock 4 hit Refill Point almost three weeks before Paddock 3, and but for a chance 12 mm rainfall would have gone into critical deficit in early November.

Let’s compare these graphs a bit more closely.

We see they tracked about the same to start with, then at the beginning of November Paddock 4 suddenly used significantly more water from the 0 ‑ 30 cm root zone than did Paddock 3. This is around the time the canopies reached full ground cover.

Our observations of the crops suggest Paddock 3 had more canopy so we thought it would be using more water than Paddock 4. Looking at the lower parts of Graphs 3a and 4a, we see that Paddock 3 used more water from deeper in the profile at 40 – 50 cm.

We did some Visual Soil Assessments and found more evidence of soil compaction in Paddock 4. Being the main gate access into the area it has seen more tractors, trucks and paddock forklift activity. So we expected to see compaction limiting root development.

Now lets look at the water content in the whole soil profile, right down to 80 cm, presumably well past any pea roots (Figures Paddock 3b and Paddock 4b).

Paddock_3_b
Paddock_3_b
Paddock_4_b
Paddock_4_b

The first thing to notice is much higher water storage, because 80 cm of soil has more readily available water than 30 cm of soil. So now Full Point is 314  mm and Refill Point is 232 mm giving 82 mm of readily available water for our crop to grow before we would need to irrigate.

When we compare these two graphs we get a different picture. Now we see the two crops using similar amounts of water through until 14 November. After that, Paddock 3 (the fuller canopy and better soil condition) used slightly more water than Paddock 4, and actually hit Refill Point a day or so earlier.

Overall, it seems our Paddock 3 crop is getting more water from deeper in the profile, accessing water from 50 ‑ 80 cm deep.

For a lower price crop like peas, reducing costs makes a big difference. Can avoiding compaction save the need to irrigate?

How deep are your crops’ roots?

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Many thanks to HydroServices for the soil moisture monitoring at the MicroFarm

Intensive cropping: Dealing with reality

We have a group in Hawke’s Bay focused on best management for field cropping.  We want to know how far we can push production without degrading the soil, our base resource.

We have drafted a five year cropping programme, based around process crops, but with other crops in the mix. This is typical in the region where process crops are mixed with onions, squash, some cereals, occasional potatoes and often winter grass.

In our programme we have tried to eliminate animals and pasture, looking instead at maximising vegetable production. Given the different seasons, season lengths and the realities of planting dates that must fit factory schedules, this gets a bit tricky.

Central to our plan are vining peas and green beans, two crops with specialist harvest equipment. Viners are very heavy. The bean harvester weighs in at about 18 tonnes plus 4 tonnes of crop when full. The pea viners are around 22 tonnes, plus a couple more of crop when full.

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These machines have large wheel or track footprints, so impact a wide path. And pea viners typically travel across the lie of the crop, not up and down rows, so can track anywhere. How does that fit our plans to adopt controlled traffic!

Gary Cutts of Tasman Harvester Contractors is at the centre of the action. The company currently has nine harvesting machines with a price tag of around $1million each. From December, the machines earn their keep, harvesting 24 hours a day, seven days a week.

Peas are a very delicate crop and only have a premium harvesting window of 24 hours. Before that they’re too young, and after that they’re too old. It’s an exact science to determine when to pick.

For a successful harvest Gary’s team must respond to demand from the factory and deliver on time. Delays that affect factory processing are costly.  

The new harvesters, especially those on tracks, can get on to the ground even in very poor weather. But what is their impact on the soil? They are very heavy, they have big feet, and the soil may be weakened by wetness.

Gary contacted Marc Dresser at Landcare Research after hearing him at a LandWISE Conference. Marc is a specialist in soils and mechanical engineering whose knowledge is unrivalled. He worked with Gary on tyre selection and tyre pressures to optimise performance.

Together they reduced harvester tyre pressures from around 30psi to 20psi. They reversed the direction of jockey bin tyres too. Gary says the difference is immediately noticeable in the field. Coupled with a change to tracks, the soil load has been greatly reduced.

Gary still wants to know what the impact on the soil is. Are harvesters doing damage? If they are causing compaction, what is best practice remediation? When should it be done? How does it impact following crops?

We want to know too. And we want to know what a farmer can do to best prepare their soils before the harvesters arrive. Before the crop is even planted.

We can control traffic in pretty much all operations with the equipment in use now – except for the viners. We’ve looked at a number of scenarios, which suggest that the 30” row is the factor that sets the standard. Smaller tractors might straddle two rows, bigger machines can straddle four. If equipment is sized accordingly, we can get the trafficked area down to about 17% of the ground. Except for the viners.

Most paddocks only see peas about once in five years, so that leaves 4 years and 11 months of controlled traffic. But in our super-intensive farm, we might see peas almost every year and green beans too. We really do need to know how to manage this aspect of some of our important regional crops.

Frustration to Irritation

Many irrigators would identify with Hugh Ritchie’s presentation title, “From Frustration to Irritation”, in which he related his 13 year journey from dry land to irrigated farming.

Speaking to 74 delegates at the LandWISE/Irrigation New Zealand “Going into Irrigation” conference, Hugh said irrigation was the key to unlocking profitability, allowing the farm business to develop significantly. Yields have increased across the entire crop range, higher value crops have replaced low value options, and consistent yields stabilised income and enabled development and growth.

Before irrigation, the Ritchies grew arable and ryegrass seed crops and ran some deer. Now the deer are gone, and a wide range of process and fresh vegetable, arable, and high value seed crops are grown, with some sheep in the mix.

Looking back, Hugh realises he has learnt an immense amount about irrigation. What would he do differently if starting again? He’d probably design the farm around the irrigation, not fit the irrigation to the farm layout he had. “My irrigators don’t like trees,” he said. “They always come off second best!”

Tony Davoren from Hydro-Services discussed supply reliability and volumes. He showed the seasonal requirement for water for a mixed cropping operation. Piling crop demand on crop demand across the season, he showed peaks where volume is needed at times when reliability is critical. Inability to meet peak demands will impact yields. “The first 90% of yield goes to pay your costs,” he said. “You cannot afford to lose yield through water-shortage: that loss was your profit. Access to reliable supplies is vital.”

When should you start planning your irrigation system? Stephen McNally from OPUS Consultants showed that, whether major scheme or on-farm system, the same planning is needed. And it takes a long time from start to finish. To start irrigating in four years, start planning now.

Stephen stressed the need to gather resource information to reduce uncertainty, to determine irrigation system needs and costs, and to constantly review them against the farm business plan. Stephen also cautioned against taking cheap up-front capital options. Cheap systems invariably have high running and maintenance costs, and these rapidly outweigh any savings made at the start.

Dan Bloomer discussed “Specifying an irrigation system”, one subject of new Irrigation NZ resources for potential irrigators and irrigation managers. These contain valuable information and checklists to ensure potential irrigators collect all the information needed for a designer to do their job.

Carolyn Hedley developed the theme in “Assessing a farm for irrigation”. Carolyn discussed irrigation system options, the critical role of soil, and the availability of soils information via Landcare Research’s website “S-Map”. The use of new soil survey techniques was also discussed.

California Water Resources and Irrigation Advisor, Michael Cahn, explained how fertigation can be used to manage nutrients. This is an important aspect of irrigation in California, and increasingly in New Zealand. As farming intensifies and environmental limits are reached, care with nutrients is vital. Fertigation allows “just-in time” application, minimising any risk of leaching or volatilisation losses – saving money and the environment.

Andrew Curtis outlined Audited Self-Management to support good irrigation practice and provide assurance to the community that the water, a common good, is being appropriately used. He noted the responsibility irrigators have to demonstrate excellence in irrigation, and that audited self-management could reduce the overall cost of compliance monitoring.

Farm visits followed.

Lindsay Smith discussed his choice of irrigation for dairying, and his concerns about access to groundwater and links with the proposed Ruataniwha Water Storage scheme.

Ian Annan described how MrApple is ensuring maximum use is made of limited water, and that all conditions are met.

The day wrapped up at Mike Rittson-Thomas’ buried dripline irrigation system. “It was put in anticipating a five year life. Thirteen years on it is due for replacement but I have to be happy,” Mike says. “Now I’m waiting to see if the Storage Scheme goes ahead. If it does my options open up. I currently have limited water, so if it doesn’t, I’ll be looking at this again to eke out what I have.”

LandWISE and Irrigation New Zealand partnered to present the John Deere, Hawke’s Bay Regional Council and FMG sponsored special-focus day. Seventy four people heard from eight presenters, then moved out to visit and hear the experiences of the three farmers; dairy with pivots, orchard with micro-sprinklers, and sheep/beef farmer with buried dripline in lucerne.

 

Vegetables in the Israeli Desert

This article was first published in The GROWER magazine following a trip to the UK and Israel to study water policy.

The Desert Blooms: vegetables from recycled water in Israel

 

We left Tel Aviv amid high security, the day after fighting began in Gaza. It was a sobering end to a tour of irrigation and horticulture in Israel.

In Israel, land is owned by the state, and a licence granted to farm it. There is, relatively speaking, a lot of land. There is virtually no water. Water is managed by the State, in trust on behalf of the people.

It’s a nation that desalinates almost a billion cubic metres of water a year, and uses 700 million for agriculture. The key is that agriculture is the second use: almost all ag water is recycled from cities. Parallel pipelines carry fresh and recycled water for thousands of kilometres around Israel. The huge infrastructure cost is borne by the state – it is a matter of national importance.

Much of our tour focused on drip irrigation, including a visit to its developers at Kibbutz Hatzerim, the home of Netafim. Hatzerim is 8 km west of Beersheba in the Negev desert. In such an inhospitable environment, the need for detailed management and high efficiency rapidly becomes obvious.

We visited the Arava Valley, south of the Dead Sea. This is the border with Jordan, currently peaceful after a treaty in 1994. Don’t jump the fence though, the explosive mines are still there, and flooding has redistributed them to who knows where.

In an area with 50mm of rain (if any) and 2,000 mm of evapotranspiration, water is a valuable commodity. The soils are saline, the water is saline. Drip is about the only way plants can be made to survive.  And survive they do, in soil brought hundreds of kilometres, with water brought hundreds of kilometres, to produce crops for consumption thousands of kilometres away in Europe. Why?

The key for the state, it seems, is occupation and security. The key for the farmers is a climatic opportunity that allows excellent production when Europe is freezing. Growing almost exclusively in tunnel houses of plastic or shade, yields can be very good and quality excellent. With water supplied to the district by the state, and to the gate by local agencies, it is supply that is limiting more than cost.

A typical farm is about 4ha, although some are increasing through aggregation. Key crops are capsicums (Bell Peppers) and table tomatoes, which together account for most production. All crops must be removed for a period around July to break pest and disease cycles. Farmers believe the policy is effective, as they have very low levels of disease or virus.  At this time it is too hot to grow anything anyway, and most people head to the coast for a holiday.

Farmers spoke of constraints. New development needs water which is seldom available. Their children want to move to the cities and high paying professions. Tomatoes produce about 20kg/m2, which farmers say is profitable. But they require three times the labour of capsicums, and some farmers just cannot get enough labour to increase production.

Innovation and entrepreneurship are alive and well. We visited a huge reservoir for an almond, olive and grape farm of several hundred hectares. To our Kiwi noses and eyes the water was filthy; to them it was gold. In the distance was its source, Arad, a city of 23,000 people drinking and flushing desalinated water and supporting Israeli agriculture.

Dan Bloomer, LandWISE

My thanks to Andrew Gregson of the NSW Irrigators’ Council for organising the study tour, colleagues Andrew Curtis (IrrigationNZ) and Hayden Cudmore (Australian Rice Growers’ Association) and those who hosted us along the way. Dan’s visit to Israel was self-funded.

 

Steps towards Farming Within Limits

The article was first published in The GROWER magazine.

Farming within limits is the phrase of the year, by-line of numerous conferences, and part of many conversations. Farming within limits is nothing new. Financial constraints, market size, climate and soils, labour . . . you name it.

But farming within off-farm environmental limits puts a new spin on the topic. Both regulators and growers are under pressure to lift performance. Fortunately Horticulture New Zealand took a lead role years ago when it launched New Zealand Good Agricultural Practice.

New Zealand GAP is constantly evolving to meet new opportunities and requirements. And the bar will continually lift as governments, markets and other stakeholders expect ever higher standards from producers. But good agricultural practice is, and will be, the core of farming successfully within limits.

Successful growers already aim for profitable production with environmental stewardship. They have systems that ensure the basics are done well, and for continuous improvement. They measure to manage, they record to report.

These leaders of the pack are prepared for, and often do well from, change. They have a mind-set of adapting management to meet or beat changing situations. They already do a bit extra such as riparian planting and supporting local stream care. They are ready for most, if not all, that “farming within limits” may throw at them.

It is a year since the National Policy Statement (NPS) for Freshwater Management 2011 came into effect requiring councils to set limits on fresh water quality and the amount of water that can be abstracted from our rivers, lakes and aquifers.

Councils have four years left to establish programmes that will give effect to the NPS by 2030. They will need to amend regional policy statements, proposed regional policy statements, plans, proposed plans, and variations. It is a lot of work, and councils are under pressure to have the necessary changes in place sooner rather than later.

Government stated, “We are committed to monitoring improvements in fresh water management from the NPS and reviewing its effectiveness within five years as the complete package of reforms is rolled out.” There is a strong sense of urgency.

Growers can take action now. Both on and off-farm activities are needed, and many things can happen in parallel. There is a need to be involved, and no need to wait to do things better.

The freshwater quality driver points to many things; irrigation and nutrient management, soil conservation, stream enhancement, eel fishery management, and a range of environmental offsets. It is the effect of the combination of all management and mitigation that will determine the outcome.

Of the off-farm activities, Horticulture New Zealand Natural Resources and Environment Manager, Chris Keenan, says, “The key task in front of growers right now is participating in a limit setting process, because that will determine how much effect limit setting will have on the business.” Chris Keenan further notes that if they are going to do this effectively, they will need to be organised. Catchment management groups will be necessary in many cases, if not all cases.

On-farm, growers can adapt their management.

Two critical on-farm factors under direct grower control are water and nutrient management. We can’t control the rain, but we can definitely control irrigation and artificial drainage. And we are in control of our fertiliser application and can do quite a lot to keep nutrients in the root zone.

Our evaluation of irrigation systems and irrigation management records shows a wide range of performance. Some growers are highly focused, manage intensely and have high water use efficiencies.  Unfortunately, some don’t.

Without carefully monitoring soil moisture levels, weather forecasts and irrigator performance testing, effective efficient irrigation is impossible. You must know how much is needed, and how much is going on. If the basics are not right, no amount of fancy technology will help.

The same is true for nutrient management where a wide range of performance is evident. Some growers apply excellent soil fertility testing, nutrient budgeting and planning, and fertiliser spreader calibration; essential steps to maximise nutrients use.

Water and nutrient management are closely linked. Too much water will cause unnecessary nutrient loss to freshwater, just as will too much fertiliser.  Too little water reduces crop growth which leaves unused nutrients in the soil, often also increasing losses that end up in freshwater.

Fortunately, efforts to manage water and nutrients better can improve farm profitability as well as environmental performance. So it can be a win-win. Focus on getting the basic things right. Look for big, easy gains first. Then look at fine-tuning.

Catchment management groups, farmers getting together to manage the overall effect of all activities on the quality of water in each catchment, are a powerful way to make progress. Such groups provide a forum for ideas, a place of co-operative learning, agreement on actions and priorities, and opportunities for benchmarking performance.

If everyone performed at the level of the top quarter, overall performance would rise significantly. Then the community would be able to see the fresh water quality improvements sought.