Early April 2017
The season has turned. It’s now early April and we’ve just had a week of on-and-off rainfall. At times it was heavy enough to cause areas of surface flooding - a dramatic contrast to the drought we had been experiencing!
And with all this moisture, I have decided it is a good opportunity to sow cover crop seeds (green manure crop) into the cleared and cultivated garden beds. Usually I do this next month, which allows more time and garden space to grow vegetables for the farmer’s markets. But his year is different because I am about to gather up my garden tools and personal belongings and head northeast as a "travelling gardener". And I want to leave the soil in an even better condition than it was in when I arrived here seven years ago, and one of the best ways of protecting and improving soil is to establish successful cover crops.
Each variety of cover crop has its own benefits and advantages, but a personal favourite of mine is borage, which is easily harvested for the compost heap or mulched back onto the soil with its large, hollow, succulent stems. It is known to accumulate trace elements, and it produces profuse, small, attractive blue flowers which attract bees and other beneficial pollinating insects to the garden. However, because the current owner of the property plans to graze sheep on and around the garden area this winter, I am choosing to sow clover and rye grass seeds instead.
Both rye and clover share the advantages of dense rooting systems, which ultimately help build up organic matter below ground, improve soil tilth, and allow access of air and water into the soil . Rye has a particularly dense rooting system that resists soil compaction, and the crimson clover I have sown has a tap root that can penetrate the soil to a depth of up to 51 centimetres (20 inches), which brings up and fixes nutrients for subsequent crops. Such dense and deep rooting systems in combination is an effective form of natural soil cultivation known as ‘bio-tillage’.
The warm, moist Autumn that we are now experiencing should support the rapid growth of good amounts of biomass for future forage or to be mowed and fed back into the soil. Whether it’s manure from grazing animals or grass cuttings from mowing, both will break down into garden soils and provide organic matter and nutrients to benefit soil life and subsequent crops. The quick growth of abundant biomass from both rye and clover also works to suppress weeds through competition for space and nutrients.
As a legume, clover, in association with a certain bacteria (rhizobium), has the ability to ‘fix’ air-borne nitrogen in a symbiotic relationship. These beneficial bacteria find a home on nodules on clover roots and provide nitrogen to the plants in return for nutrients from the plant roots, an exchange that can boost plant growth.
And with a week to go until my departure to the northeast of New Zealand’s North Island (Kerikeri), I’m pleased to see thousands of little clover and rye seedlings turning my field gardens back into pasture. And this will rest and revitalise the soil for whomever may arrive next to garden this fertile patch of volcanic-silt-loam soil adjacent to the mighty Kauri trees of Northland’s Waipoua Forest.