The Latest Co-planting of Coix and Safflower with Cyclic Improvement of Wetland Soil and Water

Brief Introduction

1. The significance of wetland soil and water improvement

With China's modernization, the rapid development of agricultural industrialization and industrialization, and the reform of agricultural planting systems. The problem of environmental pollution has become a bottleneck for social development: air pollution, soil pollution, water pollution, etc., the increase of carbon dioxide, sulfur oxide and other gases in the atmosphere and the relative decrease of oxygen, the residues of heavy metals such as lead, mercury and cadmium in the soil, and the pollution of harmful elements in freshwater bodies. How to carry out scientific, rational, safe, effective and naturally cyclic treatment, that is, maintaining economic development while ensuring ecological balance, is the primary task of every one of us as citizens, planning for the long term, thinking of the next generation, sharing the nation's concerns and benefiting the people.

2. The role of co-planting safflower with Coix in the cyclic improvement of soil and water

Safflower is an annual herbaceous plant of the Asteraceae family, with a plant height of 80--120 cm and an upright stem. It prefers a warm climate, is relatively tolerant of drought and also tolerant of cold, with strong adaptability. In Shandong and other Huang-Huai regions, it is sown in autumn and harvested in early summer, being a half-year dryland plant. Coix, however, is exactly the opposite of safflower in growth habits: it not only prefers moist soil but can also tolerate living in water for a certain period, and is most afraid of drought and water shortage; its vigorous growth period is in June after the safflower harvest. Therefore, inter-planting and co-planting safflower with Coix is early in one and late in the other in terms of growth time, which exactly suits the climate pattern of Shandong; in terms of growth habits, one is dry and one is waterlogged, which completely matches the seasonal water-and-dry conditions of lake-beach wetlands, thereby establishing an artificial wetland treatment ecosystem and creating a relatively reasonable and practical cyclic improvement technical model for large-area environmental soil and water treatment of wetlands.

3. Considerable economic benefits

Through the co-planting of safflower and Coix, the environmental conditions in the wetland soil and water can be effectively and cyclically improved; at the same time, the dryland safflower and the wet-growing Coix fully absorb the effective elements in the soil, thereby growing vigorously and robustly, enabling the wetland soil to exert its maximum productive capacity, with two harvests a year and significant economic benefits. The benefits generated in one year, calculated at general yields: per mu (667 sq m), 20 kg of safflower commodity can be harvested, at a market price of 40 yuan/kg, totaling 800 yuan; 100 kg of safflower seed, at a market price of 2 yuan/kg, totaling 200 yuan; 300 kg of hulled Coix, at a market price of 4 yuan/kg, totaling 1200 yuan; the total is an income of 2200 yuan per mu per year.

Brief Introduction and Biological Characteristics of Safflower and Coix

1. Safflower, also known as grass safflower, is an annual herbaceous plant of the Asteraceae family. Its flowers are used medicinally, with the functions of promoting blood circulation, regulating menstruation, removing blood stasis and relieving pain. It mainly treats coronary heart disease, angina pectoris, dysmenorrhea, etc., and is an important gynecological medicine. Safflower seed has a relatively high oil content of 20-30%, and is the main raw material for safflower oil, which is currently a relatively expensive health-care edible oil. At present, the short-spine safflower variety is planted in Shandong, with strong adaptability; because its root system is well developed, it can absorb water and nutrients from deep soil layers to meet its own growth needs, so it is relatively tolerant of barren soil and drought. Its flowering period is in May, and the seeds mature in early June.

2. Coix is a wet-growing or swamp annual grass family plant, not tolerant of drought, and is currently divided into three varieties: early-maturing, mid-maturing and late-maturing. Generally, early-maturing varieties are suitable for planting in the northwestern region, and late-maturing varieties are suitable for planting in the south, south of the Yangtze River. The mid-maturing variety is most suitable for the central Huang-Huai region such as Shandong. The above is classified according to their characteristics. In Shandong, Coix is generally sown in May when the ground temperature stabilizes above 20°C; the seedling stage is 40 days. Stem elongation (jointing) is 16 days, booting is 8 days, the grain-filling period is 60 days, and the whole growth period is about 124 days. Especially in the middle and late growth stages, it can relatively strongly tolerate the salt damage and moisture brought by swampy land. The water requirements throughout the growth period can be summarized as follows: (1) moist seedling growth for 40 days (2) dry jointing for 15 days (3) water present for booting for 8 days (4) sufficient water for heading and grain filling for 60 days (5) dry field for harvest and processing. Therefore, Coix has a high water requirement throughout its life, and at the very least maintaining soil moisture is key.

Specific Operation Procedures

1. Safflower sowing: In autumn, in September-October, when the surface soil in the wetland is slightly dry and can be tilled, apply 50 kg of organic fertilizer per mu as base fertilizer; after plowing and harrowing evenly (if the soil is relatively wet, plowing may be omitted), sow safflower in wide and narrow rows, with a wide-row spacing of 50 cm and a narrow-row spacing of 30 cm, using 3 kg of seed per mu. Basically no management is needed during the growth period, except around the Awakening of Insects (Jingzhe) when chemical control techniques are used to control its growth height or prevent later lodging.

2. Co-planting Coix: From early April to early May, when safflower flower buds appear, select mid-maturing Coix varieties with thin hulls and a high rice-yielding rate. In order to prevent the harm of smut disease occurring on a large scale in Coix, the seeds must be treated before sowing. The treatment method: choose a sunny day to sun-dry the seeds for 1-2 days, then soak them in water for 24 hours, remove and drain the water, and dress the seeds with 0.4% triadimefon. After seed treatment, sow one row of Coix in the wide rows of safflower, using 5 kg of seed per mu. From mid-to-late May to early June, after the safflower and seeds are harvested, this is also when the annual plum rain season begins; the water level of the tidal-flat wetland rises, providing favorable conditions for the growth of wet-growing or aquatic Coix. Basically no management is needed, and it can be harvested in September--October.

Comprehensive Social Benefits of the Co-planting Model

Because tidal-flat wetlands must go through a flooding period and a drying period every year, and these are clearly seasonal. According to scientific research analysis, during the flooding period, the denitrification effect of general wetlands is much stronger than that of dryland, so the nitrogen content is relatively low; while the content of available phosphorus increases, because after the soil is flooded, the pH rises, which can promote the hydrolysis of iron phosphate and aluminum phosphate, turning occluded phosphorus into non-occluded phosphorus, and the availability of phosphorus is somewhat improved. Therefore, under the alternating conditions of flooding and drying, the available phosphorus content increases during the flooding period. The content of other trace elements such as boron and iron decreases during the flooding period, while the content of manganese and copper increases. Based on the above analysis of wetland soil nutrients, combined with the growth habits of safflower and Coix, the environmental conditions of the wetland after drying are exactly the whole growth period of safflower, while the season prone to flooding is exactly the vigorous growth period of Coix. Safflower and Coix are deep-rooted crops; their massive root systems can penetrate 50 cm into the soil, and most are distributed within 30 cm of the surface layer around the plant. Therefore, after drying, the wetland, through the safflower root system, absorbs excess elements such as nitrogen and phosphorus that accumulated in the soil due to the previous year's flooding period, to satisfy its own growth needs. At the same time, through the absorption and utilization of organic or inorganic substances in the soil, it reduces the pollution to the soil caused by heavy metals formed by these excess elements, improves the soil, and prevents the wetland soil from causing secondary pollution to water quality after rainwater or rising water levels, ensuring the purity of the water quality. After June, the safflower has been completely harvested, and Coix enters its vigorous growth period, which is also the critical period when water quality is most easily polluted; during this period, various aquatic organisms multiply in large numbers. If the content of organic matter in the water can be reduced, the growth and reproduction of various aquatic organisms can be effectively inhibited. This period is also, in general years, the period with the most rainfall; the wetland may accumulate water in a short time and become shallow water flats, and this period is also the peak water-demand period for Coix. As long as water does not accumulate for a long time, Coix will grow vigorously; the soluble organic matter in the water body is adsorbed, absorbed and decomposed and removed through the biofilm of the Coix root system and biological metabolism processes, and harmful substances such as cyanide and phosphorus can be effectively removed, achieving the purpose of purifying water quality and reducing pollution of the water body.