Orchard grass cultivation: orchard grass growing technology, orchard grass planting and management

At present, many fruit growers engaged in organic and traditional cultivation have implemented grass cultivation, and the orchard presents a green scene, which is full of ecological beauty. However, there may be many problems in the implementation of grass cultivation in orchards, such as the possibility of parasitic disease vectors, competition with fruit trees for soil nutrients and moisture, affecting soil properties, reducing the yield and quality of agricultural products, and the inconvenience of farming, and so on. as a result, many fruit growers are discouraged, forming obstacles to the promotion of orchards and grass cultivation, so as to address the concerns of fruit farmers in this regard, and then adopt grass cultivation.

Grass cultivation and soil moisture

There are three kinds of orchard irrigation: flooding irrigation, sprinkler irrigation and drip irrigation. except for drip irrigation, the other water use efficiency is not ideal. Among them, flooding irrigation is widely used because of its simple equipment, but its water use efficiency is the worst, so reducing the number of flooding irrigation can save irrigation water. The experimental results show that in the same orchard, the soil water content of Bermuda grass is higher than that of bare land, in short, the soil water retention of grass cultivation is better, so grass cultivation can prolong irrigation time and reduce irrigation times. to achieve the purpose of saving water and reducing irrigation labor.

The better water retention of grass soil after irrigation may be due to the fact that grasses help to conserve water, grasses can regulate their own evapotranspiration and grass mulching can reduce surface evaporation. As for the orchard to avoid stagnant water after torrential rain, in order to avoid the influence of soil water saturation time on root respiration, grass cultivation is carried out in orchard, and grass soil is easier to dry than bare soil, which can reduce water immersion time. The reason should be related to the reduction of infiltration, the increase of macropores left by runoff roots, the increase of leakage rate, and the adjustment of grass to evapotranspiration. Therefore, the implementation of grass cultivation in orchards has a positive effect on maintaining soil moisture after general irrigation and removing soil moisture after torrential rain.

Grass cultivation and plant nutrients in soil

After the grass cultivation in the orchard, there will be the problem that grasses and fruit trees compete for soil nutrients. Fruit farmers are worried about the decrease of fruit yield and quality due to nutrient competition, but they can be supplemented by estimating the amount of grass removed from the soil in the orchard. The nutrients of fruit trees will not be lacking, so from the point of view of nutrient management, grasses in orchards can co-exist with fruit trees.

Taking the Bermuda grass newly planted in a lotus garden for two years as an example, about 40 cm long Bermuda grass was cut at the beginning of October, and 5.5 metric tons of fresh grass could be obtained per cent of land. After drying, the current amount of nutrients was analyzed. It is found that about 17 kg of nitrogen, 32 kg of phosphorus and 41 kg of potassium oxide are absorbed by the grass, and 20 plants of lotus mist are planted per minute. The average amount of nitrogen, phosphorus and potassium oxide per plant is about 0.4,0.8 and 1.0 kg per year, respectively, compared with the recommended amount of nitrogen 1.0 kg, phosphorus 1.0 kg and potassium oxide 1.0 kg / year per plant. It is obvious that grasses compete for a lot of nutrients, so it should be supplemented.

Although grasses compete with fruit trees for nutrients, on the other hand, grasses are sharp tools to intercept possible loss of nutrients. Studies have pointed out that the roots of covered crops can absorb a large amount of available nitrogen in the soil, thus reducing the leaching of NO3, while the nutrients contained in grasses will still be released after death and decay, which will be reused by fruit trees. At the same time, this effect will return the nutrients leached down to the surface of the soil and increase the utilization rate of fertilizer. A lot of nitrogen fertilizer is applied in fruit tree cultivation, which is easy to be lost due to leaching. Grass cultivation can reduce the leaching loss of NO3 and groundwater pollution. Compared with the general bare land after the application of chemical fertilizer, there is a considerable amount of loss, and it is not easy to recover.

Grass cultivation and soil properties

Soil properties, whether physical, chemical or biological, are related to the growth, yield and quality of fruit trees. soil acidity and alkalinity affect the availability of soil nutrients and soil microbial activity. Bare soil is often eroded by rainfall, and its nutrients are lost or leached downwards, in which the loss of basic ions, such as calcium and magnesium, will acidify the soil, which is disadvantageous to the growth of most crops.

On the contrary, grass can reduce the loss of nutrients in soil, and the loss of basic ions such as calcium and magnesium can ease the rate of soil acidification. Soil organic matter is the index of soil fertility. High content of organic matter represents fertile soil, and grass is transformed into soil organic matter after death and decay. Generally speaking, in the same environment, grassland soil is easy to produce a large amount of organic matter because of its dense root system. However, the plant roots densely distributed in forest soil are less, and the withered branches and leaves on the ground are easy to be decomposed, so the content of organic matter left in the soil is low. Grass cultivation has a direct effect on improving soil organic matter in orchards.

The direct function of soil organic matter to soil properties, to the growth of higher plants and to soil organisms has long been well known. for example, soil organic matter is an important place to store nutrients, which can be released or dissolved by mineralized soil nutrients for absorption by fruit trees. it can also be used as carbon and nitrogen for soil beneficial microbial activities. And other elements to activate soil microorganisms, and because soil organic matter can reduce soil cohesion, plasticity and adhesion, making the soil convenient for ploughing. In addition, organic matter can promote and stabilize soil particles, make the soil aerated and permeable, suitable for plant growth and so on, so it is obvious that fruit tree grass cultivation can improve many soil properties indirectly after improving orchard soil organic matter.

Due to the direct impact of rainfall, bare soil is easy to disperse and suspend soil particles, so small soil particles fill pores, resulting in soil compaction, thus inhibiting the extension of crop roots and reducing the ability and range of fruit trees to absorb nutrients. The adoption of grass cultivation can not only avoid the direct impact of rainfall on the soil, but also avoid the direct impact of rainfall on the soil. After the grass root extends into the soil layer, the metabolism of the grass root, and the death and decay of the old root will leave pores, so the grass soil naturally has more pores than the bare soil, which can reduce the soil compaction obstacles. The macropores produced are more helpful to improve the soil hydraulic conductivity, which is as much as 16 times because the pore diameter is doubled. It is of great help to reduce the suffocation of crop roots due to excessive asphyxiation and reduce the harm of runoff or erosion.

The relationship between Grass cultivation and Diseases and insect pests

However, grass cultivation has both positive and negative effects on diseases and insect pests of fruit trees. Foreign studies have pointed out that planting green manure as mulching crops in citrus orchards or vineyards in winter can reduce the population of pests. However, winter rape green manure promoted in Taiwan seems to attract white butterflies during flowering, and if it is used for grass cultivation in orchards, it will be harmless to fruit trees. He Kunyao's (1992) experiment pointed out that in apple and cherry orchards, the vegetation cultivated with dicotyledons as grasses was better than that with monocotyledons, because there were more natural enemies in dicotyledons, while more leaves were found in monocotyledons. Therefore, although under general circumstances, the mulch crops for herbaceous cultivation of fruit trees have strong resistance to diseases and insect pests, sometimes diseases and insect pests occur, whether fruit trees are attacked or infected at the same time, and whether grass plants become parasitic plants that harm fruit tree diseases and insect pests, or whether they can reduce the occurrence of fruit tree diseases and insect pests are worth studying, in order to find out which orchards and which vegetation is the most favorable.

Compared with bare cultivation, grass cultivation in orchard can conserve soil moisture better, reduce irrigation times, and achieve the goal of saving water and labor. In the implementation of grass cultivation, grasses among fruit trees will compete with fruit trees for nutrients in the soil, but timely application of fertilizers that may be absorbed should not affect the growth of fruit trees, and the nutrients absorbed by grasses will eventually be returned to the soil. it is helpful to increase the content of soil organic matter and promote the activity of soil beneficial microorganisms. In addition, grass cultivation can improve many soil properties that are closely related to crop growth, so in terms of soil and fertilizer management, orchard grass cultivation has a number of positive effects and its negative effects can also be overcome, and the effects of orchard grass cultivation on fruit tree diseases and insect pests can also be evaluated and selected to be suitable for orchard grass cultivation.

Grass cultivation in orchard means to let weeds grow among the rows of orchards, or to plant non-native grasses, green manure crops, etc., and to manage them, the purpose of which is to control weeds without herbicides. Organic agriculture emphasizes that chemical synthetic pesticides are not used to control weeds, diseases and insect pests, so grass cultivation in organic orchards is one of the choices.