Analysis of Key Technologies and Economic Benefits of Deep-Buried Drip Irrigation for Cotton

Cotton "deep-buried" drip irrigation technology is another new high-efficiency water-use technology that has emerged following cotton subsurface hose micro-porous irrigation technology. This technology can utilize fertilizer and water with high efficiency, and its yield-increasing effect is obvious.

I. Key Technologies

1. Irrigation

The start of irrigation is at the cotton squaring stage. In the cotton region of northern Xinjiang, this is generally June 7-10, with irrigation carried out on a 3-day rotation cycle. If autumn is rainy, irrigation can be carried out on a 5-day cycle. Irrigation amount: at the squaring stage, each irrigation is 8 cubic meters per 667 sq m; at full flowering, 10 cubic meters; at the boll stage, 12 cubic meters. During the whole growth period, irrigation is applied 21-23 times, with a total irrigation amount of 220-240 cubic meters per 667 sq m, and water is stopped around August 14.

2. Fertilization

According to the soil-testing formula fertilization standard, on the basis of deep fertilization in autumn, the base fertilizer is mainly phosphate fertilizer and potassium fertilizer, and during the growth period nitrogen fertilizer is mainly applied through drip irrigation, with water and fertilizer managed according to "one irrigation, one fertilization." At the squaring stage, 2-3 kg of urea is applied each time per 667 sq m; at the flowering and boll stage, the fertilization amount is increased, with 3 kg of urea applied each time per 667 sq m. During the whole growth period, 25-31 kg of chemical fertilizer is applied per 667 sq m. Because the irrigation filtration equipment has strict requirements for monopotassium phosphate, drip-irrigated cotton fields can use manual spraying to nourish the cotton field.

II. Comparison of Economic Benefits

In 2005, the cotton "deep-buried" drip irrigation project area in Ershilidian Town, Hutubi County had an average lint yield of 147.1 kg per 667 sq m. Compared with conventional furrow irrigation, cotton had obvious advantages in the number of retained seedlings, number of fruit branches, number of bolls, boll-setting rate at the top, single boll weight, and yield, and the rate of empty fruit branches was also lower. The comparison results are as follows:

Comparison Table of Deep-Buried Drip Irrigation and Conventional Furrow Irrigation

Irrigation method Number of plants per 667 sq m Number of bolls per plant Average growth amount Average plant height Number of fruit branches Single boll weight Lint yield (kg Increased lint (kg

(plants) (bolls) (cm) (cm) (branches) (g) /667 sq m) /667 sq m)

Deep-buried drip irrigation 11600 6.5 1.1 70 8.1 5.0 147.1

Conventional furrow irrigation 11500 5.3 0.9 96 5.6 4.8 113.8 33.3

From the table above, it can be seen that deep-buried drip irrigated cotton increased lint yield by 33.3 kg per 667 sq m compared with conventional furrow irrigated cotton, an increase of 29.3%. Calculating the lint unit price at 10 yuan/kg (the average market price of the past 5 years), the net increase in output value of the main product is 333 yuan per 667 sq m; the by-product (cottonseed) increases by 50 kg, calculated at 1.2 yuan/kg, for a net increase in output value of 60 yuan per 667 sq m; the combined increase in output value of the main and by-products is 393 yuan per 667 sq m. Apart from the newly added cost of 118.2 yuan per 667 sq m (including equipment cost of 110 yuan per 667 sq m, newly added picking cost of 56.2 yuan per 667 sq m, saving irrigation labor of 2 persons x 20 yuan = 40 yuan per 667 sq m, and saving one manual weeding, 8 yuan per 667 sq m), the profit per 667 sq m is 274.8 yuan more than furrow irrigation, showing significant economic benefits.