What are the improvement measures for saline-alkali wasteland?

There are about 200 million hectares of saline-alkali land in China, a considerable part of which is undeveloped saline-alkali land. In order to make full use of and develop saline-alkali land, expand the planting area of fruit trees, and improve the yield and quality of fruit trees, soil improvement must be carried out first, and reasonable soil improvement measures should always be maintained after the garden is built.

(1) Set the irrigation and drainage system. Drainage and waterlogging prevention, irrigation and salt washing. In areas with water conservancy facilities, seawater desalination is one of the fastest and most effective methods to improve saline-alkali land. "Salt comes with water and salt goes with water" is the general law of salt movement, and it is also the main way of salt accumulation and leaching in soil.

Dig a drainage ditch every 20 ~ 40m along the orchard. General ditch depth 1m, ditch top width 1.5m, and ditch bottom width 0.5 ~1.0m.. The drainage ditch is connected with the larger and deeper drainage branch canal and the main drainage canal, and various channels should have a certain slope to facilitate smooth drainage and discharge the saline-alkali in the garden. Fresh water can be introduced into the park regularly for irrigation to achieve the purpose of irrigation and salt washing. If the soil salt content reaches 0. 1%, attention should also be paid to long-term irrigation, alkali suppression, intertillage, mulching and drainage to prevent salt from increasing.

(2) Dredging and improving saline-alkali land. Siltation irrigation is to pump the river water containing sediment into the field with pre-built ridges through the canal system, and deposit the sediment and soil by reducing the flow rate. This method can be used not only for the improvement of low-lying waterlogged land and saline-alkali wasteland, but also for the improvement of sandy wasteland and other barren land. Silting measures have been adopted to improve saline-alkali land in many places in the middle and lower reaches of the Yellow River in China.

(3) Deep ploughing and application of organic fertilizer. Organic fertilizer not only contains nutrients needed by fruit trees, but also contains organic acids. Organic acids and bases neutralize each other. At the same time, with the increase of organic matter content, the physical and chemical properties of soil will be improved, which will promote the formation of aggregate structure, improve fertility, reduce evaporation and prevent alkali return. Practice has proved that soil organic matter increased by 0. 1% and salt content decreased by 0.2%.

(4) Ground coverage. Sand, grass or other substances on the ground can prevent saline-alkali from rising. For example, in the vineyards of Wenshui County, Shanxi Province, in the dry season, spreading 10~ 15 cm of sand or covering 15~20 cm of grass on the saline-alkali land can play a role in preserving moisture and preventing the saline-alkali land from rising.

(5) Building gardens and planting green manure crops. Planting saline-alkali tolerant gardens can reduce wind speed, reduce ground evaporation and prevent soil from returning to alkali. Planting salt-tolerant green manure crops can not only increase organic matter and improve soil physical and chemical properties, but also cover the ground with branches and leaves of green manure, reduce ground evaporation and inhibit the rise of salinity. The experiment shows that after sesbania planting 1 year, the salt content in 0~30 cm soil layer can be reduced from 0.65% to 0.36%, and the effect is better if it is combined with drainage and alkali washing. Selecting salt-tolerant tree species, varieties and rootstocks can also improve the natural salt tolerance of fruit trees.

(6) chemical modifier. Chemical modifiers, such as gypsum, phosphogypsum, sulfur-containing or acid-containing substances (such as crude sulfuric acid, slag sulfur powder, etc. ), humic acid and acid and physiological acid fertilizers (such as calcium superphosphate and ammonium sulfate, etc.). ) can improve saline-alkali land.