Citrus cultivation

1 soil selection

Mineral nutrients and water needed for the growth and development of citrus are mainly absorbed from the soil. In citrus planting, it is an important content of orchard management to improve soil by various technical measures to achieve high yield, high quality and high efficiency.

1. 1 deep soil layer.

Citrus is a deep-rooted fruit tree, and the root system development needs a deep soil layer, which is generally required to be above 0.8 ~1.0m. Orchards with shallow soil layer need to be improved and thickened to meet the requirements of citrus growth and development.

1.2 fertile soil

The mineral nutrients needed for the growth and development of citrus are mainly absorbed from the soil, so the soil is required to be rich in nutrients. Generally, high-yield orchard soil needs 2% ~ 3% organic matter, 0. 1% ~ 0. 15% total nitrogen, 0.10.20% total phosphorus (P2O5) and 0.10.20% total potassium.

1.3 Medium pH

Citrus grows in slightly acidic soil, and pH 5.5 ~ 6.5 is the most suitable.

1.4 loose soil

Although citrus can grow on various soils, the most suitable soil is sandy loam. The growth of roots requires 3% ~ 8% oxygen in the soil, and less than 2% is not good. When it is reduced to 1.5%, rotten roots will appear, and when it reaches 8%, a large number of new roots will grow, which is most suitable for reaching oxygen close to the atmosphere.

1.5 groundwater level

Citrus is a deep-rooted fruit tree. The growth of roots requires loose soil and good drainage and ventilation. The groundwater level should generally be below1.0m.

2 Planting techniques

2. 1 reasonable close planting

Reasonable planting can make full use of land and space. According to the characteristics of Jiudushan, 50 ~ 60 permanent citrus trees are planted in the citrus orchard, and the rootstock is rich orange or bitter orange. It is planned to densely plant a temporary tree between permanent trees, with one plant per mu 100 ~ 1 10. Mountain citrus is mostly red soil, dry, sour, hard and thin. It is necessary to improve the soil to meet the needs of citrus growth and fruiting. Before planting, dig a deep, wide and long planting hole with 1 m, air-dry 5 ~ 10 kg of green manure or straw, 0 ~ 2 kg of lime/kloc-0, 2 ~ 3 kg of cake fertilizer applied to the upper layer, and 0 ~ 2 kg of phosphate fertilizer/kloc-0, and then return to the hole after mixing with the soil. Citrus seedlings should be cultivated with improved varieties and strong seedlings, and it is best to follow them before planting.

2.2 Planting period

Generally speaking, spring and autumn are suitable for planting citrus. There are two periods of spring planting. First of all, spring seedlings are planted before germination. At this time, the trees are rich in nutrition, there is more rain, and the temperature is gradually rising. After planting, it takes root quickly, is easy to survive, and is labor-saving in management. Therefore, this period is the most planted period in production; However, spring shoots germinate late or irregularly. On the other hand, it is planted after the spring shoots are ripe and before the summer shoots are pulled out. At this time, the temperature is suitable, there is a lot of rain, and it is the peak of rooting, and the seedlings recover quickly and the effect is good. In autumn, plants should be planted 10 month after the autumn shoots mature. Because of the soil temperature in Shang Gao, the roots can grow again after planting, so the spring shoots can germinate normally in the next spring, which is beneficial to crown expansion, early fruiting and high yield. However, there is little rain in autumn, watering is labor-consuming, and irrigation conditions are not available, so it is not suitable for autumn planting. Autumn planting should not be too late, otherwise, due to the decrease of soil temperature, poor root growth, leaves often turn yellow and fall off, which affects the recovery and growth of citrus, and the amount of autumn planting in this area is small.

2.3 Seedling preparation

Citrus seedlings should be planted with good varieties, Miao Zhuang and large seedlings. Planting big seedlings has strong drought resistance, easy survival and fast growth, which is one of the successful experiences of fast growth and early maturity in mountain citrus cultivation. Large seedlings require plant height 1m or so, trunk diameter 1.2cm or more, vigorous root groups and dark green branches and leaves. The orchard is near Miao Di, so it should be transplanted with soil with convenient transportation, and the seedlings dug on the same day should be planted on the same day. If the seedlings transferred from other places lose more water, the topdressing should be untied first. According to the water loss of seedlings, the roots should be soaked in water for 1 ~ 5 hours to make them fully absorb water, and the rhizosphere should be dipped in mud before planting.

2.4 transplant method

Citrus is a mycorrhizal fruit tree, and its root growth needs a well-ventilated soil environment, which is suitable for shallow planting. When planting, first dig a pit slightly larger than the extension range of citrus seedlings' roots in the small mound of planting holes, stand the seedlings in the center of the pit, facing the side where the roots grow vigorously and the direction where the wind is frequent, then spread topsoil around the roots, conveniently extend the roots, keep the roots grow naturally, and compact them layer by layer, so that the roots are in close contact with the soil without leaving gaps; Then cover with soil, and step inward with your feet slightly away from the trunk. Planting depth should be balanced between root neck and surface. Too shallow will affect survival and future growth, and too deep will also affect growth.

3 management measures

3. 1 Water retention and moisture retention

After the seedlings are planted, they must be irrigated with enough root water, and then the soil around the trunk will be made into a disc with a slightly higher outer edge and a slightly lower middle, and covered with straw or grass to keep the soil under the disc loose and moist. After planting, the survival rate is very low without watering or watering incompletely. Therefore, if it doesn't rain within one month after planting, it should be watered frequently according to the soil dryness to keep the soil moist for survival. In windy places, after planting, a pillar should be erected beside the trunk and the trunk should be fixed (www.nczfj.com) to prevent the strong wind from shaking the root system and affecting the survival.

3.2 Rational fertilization

1 ~ 2-year-old young trees should be fertilized 1 time every month during the growing season from March to August every year, or once before and after the shoot heading in spring, summer and autumn, with nitrogen fertilizer as the main fertilizer, and the amount of fertilizer applied is from less to more, generally 0.2kg ammonium bicarbonate or 0. 1kg urea is applied to each tree, and 40% is applied to each tree in combination with hole expansion and soil improvement in winter.

Planting sweet oranges

The first is to cultivate improved varieties and strong seedlings.

Varieties with large fruit, much juice, few seeds or no seeds, slag removal, solid content above 1 1%, less fruit dropping or cracking before harvest, high yield and good stability should be selected. Such as Beibei 447, Yujin Orange and Pear Orange in Jincheng Orange; Carter, olinda, Algerian and Minerva oranges in summer oranges; Bai Liu, Ting Anne, Newhall, red meat navel orange, abundant navel, etc. In navel orange; Tarocco and other new strains.

Using Fructus Aurantii as rootstock to cultivate virus-free improved varieties and strong seedlings is the basis of high yield and high quality cultivation. Seedling raising requires well-developed roots and well-healed interfaces. The height of seedlings is more than 40cm and there are more than 3 branches. Emphasis should be placed on the following, and the management of planting large seedlings with soil should be strengthened. In the following, places with loam with sunrise, convenient water sources, close to plantations, deep soil layers and high organic matter content should be selected. There are 1000 plants per mu, and the plant spacing is 60× 100cm.

Second, change the civil gardens and plant them.

(A) change the civil gardens and soil conservation

1, the whole park will be deeply overturned by blasting, and terraces with equal height will be built, roads will enter the park, and water conservancy facilities will be provided.

2. In the first half year of planting, maintain the soil in the planting ditch. The planting ditch is generally a little outside the center line of the terrace. When building terraces, topsoil should be filled into planting ditches. The planting ditch has a width of1.8m and a depth of 0.8m. It is filled with topsoil and layered with organic matter, such as municipal garbage, grass and corn stalks, with a dosage of 5000- 1 10,000kg per mu.

(2) Planting

1. Planting density: about 82 plants per mu. The standard ladder is 4m wide, and each ladder is densely planted in a single row, with 4m spacing between permanent trees, and temporary trees are inserted between permanent trees. The plant spacing is 2m, and about 4 1 plant is planted per mu after one thinning.

2. Planting time: September in autumn is after the autumn shoots mature, or before the spring shoots germinate, after the leaves of the spring shoots turn green in mid-May in summer, and before the summer shoots germinate in early June.

3, colonial technology:

Digging a planting pit: For the land that has been deeply ploughed and matured before planting, the planting pit should be able to accommodate the seedling roots; for the land that has been deeply ploughed and not fertilized, the planting pit is slightly larger to facilitate fertilization. For the uncultivated land, the planting pit with a depth of 1 m and a width of 65,438 m should be dug six months in advance, and the soil should be filled with fertilizer. After planting, it will continue to expand and dig through the whole garden.

Planting technology: put the seedlings into the planting pit, straighten the roots evenly, and fill the pit in layers, with the same depth as the nursery, neither deep nor shallow. Cover the roots with fine topsoil, gently shake the seedlings while filling the soil, slightly lift the seedlings, compact around the roots after filling the soil, fully inject water, and cut off some branches and leaves in combination with the tree shape. Water should be injected every 4-5 days in dry season.

Thirdly, the management of soil, fertilizer and water in orchard.

(1) Soil control of orchard.

Adult sweet orange orchards, if the soil layer is hard and shallow, should be deeply ploughed and expanded in autumn, and organic fertilizer should be applied to improve the soil and thicken the soil layer. Advocate planting grass or vegetables in orchards, green manure or covering grass between rows or plants, and implement no-tillage in orchards. Before the kindergarten is closed, it is forbidden to plant crops that affect the growth of sweet orange trees, such as fair intercropping and tall stalks.

(2) Fertilizer and water management of sweet orange orchard

1. Fertilization at the young tree stage is mainly based on nitrogen fertilizer, with appropriate amount of phosphorus and potassium fertilizer, and the principle of combining weakly decomposed liquid fertilizer with fertilizer and water is adhered to. During fertilization, the new shoots are fertilized once before germination and once after self-shearing, and the energy is applied seven times a year (of which165438+1mid-October is the overwintering fertilizer). 1-3-year-old saplings were applied with 5 kg of urea, 10 kg, 15 kg, 20 g, 30 g and 50 g, and 25 g, 35 g and 60 g of calcium superphosphate respectively. When the new shoot leaves reach 2/3 of the normal leaves, spray 0.3% urea +0.2% potassium dihydrogen phosphate outside the roots once, and spray again after 10- 15 days. At the same time, according to the principles of spring irrigation, summer drainage and drought resistance, the water demand of plants is guaranteed in time.

2. Fertilizer and water treatment for adult trees (including first-bearing trees): Fertilize 5 times a year. That is, spring fertilizer is applied from mid-February to early March to promote germination and strengthen flowers for the winter, with available nitrogen fertilizer as the main fertilizer, accounting for 20% of the whole year; Fruit-stabilizing fertilizer was applied in early May, accounting for 5% of the whole year. According to the tree application, more flowers and more fruits, less flowers and less fruits, only supplemented by topdressing outside the roots, to reduce the secondary physiological fruit drop. The fertilizer for promoting shoots and strengthening fruits was applied in early July, accounting for 35% of the whole year; At the beginning of September, strong fruit branches were applied to promote flower fertilizer, accounting for 20% of the whole year; In winter, it was applied before and after fruit picking 1 week, accounting for 20% of the whole year. In addition to soil fertilization, nitrogen, phosphorus and potassium fertilizers should be sprayed outside the roots in combination with pest control at pre-bud, young fruit stage, fruit expansion stage, strong shoot stage and flower bud differentiation stage. At the same time, irrigation should be carried out in spring and every 5-7 days in summer drought.

Fertilization amount per mu (kg of active ingredient): converted from 2,000 kg of fruit per mu, it is 32 kg of pure nitrogen, 20 kg of phosphorus pentoxide and 26 kg of potassium oxide, and the ratio of nitrogen: phosphorus: potassium is 1:0.6 :0.8. Organic fertilizer should account for more than 40% of the pure application amount.