Rural

Agraforum New Zealand, a key player in agricultural consultancy, focuses on the varied landscapes of New Zealand’s South Island, which present unique challenges and opportunities for soil management. The region’s predominant sedimentary soils, derived from greywacke and other sedimentary rocks, are distinct from the volcanic soils found in the North Island. These sedimentary soils, especially prevalent in areas like Canterbury, play a central role in the island’s dairy farming operations.

These soils in the South Island typically feature lower organic matter levels, with carbon content generally ranging between 3-5%. Agraforum New Zealand recognises the susceptibility of these soils to degradation, particularly due to their finer and less robust structure. “The structural challenges of sedimentary soils make them prone to compaction, significantly impacting their fertility and the productivity of our farms,” notes Dr Gordon Rajendram, a leading soil science expert working alongside Agraforum NZ.

The intensive agricultural practices common across the South Island, including continuous dairy farming and cropping, often exacerbate soil degradation. The frequent use of chemical fertilisers, such as Diammonium Phosphate (DAP) and ammonium sulphate, leads to soil acidification, which in turn diminishes soil quality. “Such practices disrupt the microbial life within the soil, which is vital for sustaining soil health and fertility,” explains Dr Rajendram.

Despite these challenges, the South Island’s diverse soil types, including loess in some regions, offer significant agricultural potential beyond traditional dairy farming. These fine, wind-blown silt particles are particularly well-suited for viticulture and certain types of horticulture, industries where the South Island has carved a niche.

One of Agraforum NZ’s testing locations

Committed to promoting sustainable soil management practices, Agraforum New Zealand advocates strategies such as crop rotation, reduced tillage, and the strategic use of soil tests and analysis to maintain or improve soil health. By adopting these sustainable practices, Agraforum aims to ensure the longevity and productivity of the agricultural lands, preserving the unique soil landscape of New Zealand’s South Island for future generations.

Contact Agraforum NZ

Mobile: 0274 485 159
Email: allan@agraforum.co.nz

www.agraforum.co.nz

Contact Phillip Quay
phillip@mediapa.co.nz
P: 0274 587 724
www.mediapa.co.nz

In the verdant landscapes of New Zealand, where agriculture forms the backbone of the economy, maintaining the right balance of nutrients in the soil is critical for both crop yield and environmental sustainability. Dr Gordon Rajendram, a renowned soil scientist, draws attention to an often-overlooked issue: the signs of excessive phosphate levels in the soil, a condition that can have far-reaching consequences for both agriculture and natural ecosystems.

Phosphate is an essential nutrient for plant growth, but like anything in excess, it can lead to problematic outcomes. One of the primary signs of too much phosphate in the soil is the inhibition of plant uptake of other necessary minerals, such as iron, zinc, and manganese. This nutrient imbalance can result in poor plant health and reduced growth, a paradoxical situation where more is indeed less.

Moreover, excessive phosphate can lead to algal blooms in nearby water bodies, as runoff carries the surplus nutrients into rivers and lakes. These blooms not only disrupt aquatic ecosystems but can also pose a risk to animal and human health. In New Zealand, with its extensive coastlines and waterways, this issue is of particular concern, highlighting the need for careful nutrient management.

Dr Rajendram points out that soil testing is a crucial step in identifying excessive phosphate levels. Such tests can help farmers and land managers make informed decisions about fertiliser application, reducing unnecessary inputs and mitigating environmental impacts.

Another sign of too much phosphate is the appearance of certain weed species that thrive in high-phosphate conditions. These weeds can outcompete crops and native plants, further disrupting agricultural productivity and biodiversity.

Phosphate holds a pivotal role in the tapestry of soil nutrients, serving as a cornerstone for plant growth and agricultural productivity. Dr Gordon Rajendram emphasises the significance of phosphate, noting, “Phosphate is akin to a key that unlocks the energy potential within plants. It’s essential for photosynthesis, energy transfer, and the synthesis of nucleic acids and cell membranes. Without adequate phosphate, plants cannot thrive or produce at their full potential.”

In conclusion, recognising and addressing the signs of excessive phosphate in New Zealand’s soils is a critical step towards sustainable agriculture and environmental stewardship. Through careful management and a commitment to balance, the country can continue to thrive both economically and ecologically.

Contact Dr Gordon Rajendram

021 466077

rajendram@xtra.co.nz

www.gordonrajendramsoilscientist.co.nz

Contact Phillip Quay

phillip@mediapa.co.nz

027 458 7724

www.mediapa.co.nz