Green manure, cover crops
Green manure, cover crops
Without complications and with a minimum investment of work, time and money we are going to take advantage to nourish and to restructure the land of the parcel of the culture of a natural and efficient form.
Green fertilizers are used to provide the soil with an active rest that allows our garden to recharge with fertility, control adventitious plants or weeds and improve the structure of the soil, all in a very simple and very little laborious way.
Green manure is a very old technique that is being widely applied today, thanks to new approaches to agriculture such as permaculture and regenerative agriculture that base much of their actions to promote microbial life and nutrients in the soil, very noticeably increasing fertility stably.
What is green manure?
Green manure is a broadcast sowing of a crop whose properties as a plant are interesting about the soil, that is to say, it is a question of sowing some type of plants that are going to improve the substratum instead of leaving it only in fallow. In this way we are going to improve the quality of the soil in different ways: providing nitrogen in the substrate through the roots, aerating the soil by the same effect removing the same roots to penetrate into the substrate, stimulate soil microbiology with the same roots, control weeds and also provide organic matter by cutting the same plant and take advantage of it as a source of nutrients and minerals.
Also, green fertilizers protect the soil from rain and heat, prevent nutritive elements in a very soluble form, elements prepared to be absorbed by the roots, are washed from the soil transforming them into organic elements, ie, prevent leaching. One of the maxims in some branches of organic horticulture is to leave only the bare and unused soil.
Which plants to use as green manure?
Crucifers such as turnips and fodder radishes, mustard or rapeseed among others are very interesting in soils poor in organic matter because they are not very demanding and require little time to develop.
Grasses such as rye, ray-grass, barley or oats are generally associated with legumes because it allows maintaining an adequate carbon-nitrogen ratio because grasses are rich in Carbon. Also, rye has allelopathic properties that inhibit the development of the seeds of many adventitious plants through toxins secreted by the same plant.
Legumes such as beans, peas, vetches, fenugreek or clovers are aerial nitrogen fixers par excellence. Normally, they are used in extensive crops because in our orchard we already have nitrogen inputs, such as compost and other amendments. But there are other great uses for legumes in an orchard, as it could be in the phases of the establishment of the orchard to condition the soil and control adventitious plants with a dense sowing drowning.
Green manure can be made with adventitious plants, alone or in combination with other species. The spontaneity of the same helps to balance the soil in an ideal way and will allow finishing with a part of the existing seeds to the soil in a natural way. Other options, such as the Phacelia, are important melliferous plants and attractants of the auxiliary fauna, a very important function in an ecological orchard.
When to sow green manure?
There are several times during the year when green fertilisers can be applied but as there are two main groups of crops, autumn-winter and spring-summer, green fertilisers will also be classified in which they are sown after a spring-summer crop and those which are sown after an autumn-winter crop.
So the green manure that will be sown at the end of the summer crops will remain until the ground is prepared for a new spring-summer sowing and planting. Normally in these cases, a mixture of cereal and legumes such as barley and vetch will be applied.
In Spring, at the end of the autumn-winter crops, there will be little time between the crops so you will sow crucifers such as mustard because it has a very short cycle. On the other hand, if time were available, a mixture of cereal-leguminous or leguminous alone as the beans.
How is green manure made?
The crop that we have used as green manure must be cut and incorporated into the soil before it forms the seeds since this is the moment when the plant is at its maximum nutrient content and it is convenient for us to take advantage of it.
So at the right time, we will proceed to grind the plant mass with a hand brushcutter and, whenever possible, leave for a few days the remains on the surface to achieve a start of decomposition. If this is not possible due to lack of time, the organic matter will be incorporated directly to a maximum depth of five or six centimetres. After a few days, the bench can be prepared for new sowings or plantations. What is achieved with this is to bring the microbial life that we have formed with the decomposition of the green manure to the depth of the cultivable soil along with a good amount of organic matter with abundant nutrients?
It is vitally important not to incorporate fresh organic matter more than five or six centimetres because it can lead to anaerobic fermentation that could release toxins to our soil and break the structure of the same soil.