Nutrient Solution Replaces Chemical Fertilizer: Cutting Back on Fertilizer and Pesticides, Raising Quality and Efficiency

Editor's note: Starting this year, the Ministry of Agriculture officially launched the “reduce fertilizer and pesticide” action, striving to have both the chemical fertilizer utilization rate and the pesticide utilization rate for major crops reach above 40% by 2020, an increase of 7 percentage points and 5 percentage points respectively over 2013, achieving zero growth in the use of chemical fertilizers and pesticides on crops. Soil testing and formulated fertilization, green prevention and control, precision fertilization, and the scientific use of chemical fertilizers, pesticides and veterinary drugs are directly related to the safety and quality assurance of agricultural products. Today this edition publishes the innovative practices adopted in Shandong, Hubei and other places in reducing fertilizer and pesticide use, for the reference of relevant agricultural workers.

Shandong vegetable farmers adopt integrated water and fertilizer cultivation substrate——

Pesticide use cut by 80 percent, yields up by 20 to 30 percent

In mid-April, when the reporter met Liu Jingwen, head of the Jingwu Ecological Fruit and Vegetable Planting Cooperative in Huanghe Subdistrict, Dongying District, Dongying City, Shandong Province, he was receiving farmers who had come from Weifang to learn. “Look, this is substrate made from decomposed cow dung. Normally you just add nutrient solution according to the crop's growth needs, and basically no chemical fertilizer or pesticide is needed. Used on our saline-alkali land, tomatoes can increase yield by more than 30%.” Liu Jingwen said as he showed the guests around.

What he introduced was the integrated water and fertilizer organic substrate cultivation technology that the village began using in 2013.

Luo Hongyi, associate professor at Shandong Agricultural University and inventor of the technology, explained: “This technology, first, uses materials commonly found in rural areas such as straw, cow dung and mushroom residue, which are decomposed and fermented to produce a substrate with stable properties and low cost; vegetables are planted in the substrate and watered with nutrient solution once a week, and the nutrient solution is formulated according to the nutrient absorption characteristics of different crops at different growth stages, as well as the characteristics of the local irrigation water. In this way, it not only greatly reduces the use of chemical fertilizers and pesticides and avoids problems such as soil compaction, pollution and salinization, but also ensures product quality and yield.”

An official from the Shandong Provincial Committee Agricultural Work Office commented that this technology converts rural waste into organic resources, and through application practice in continuous-cropping greenhouses, saline-alkali land and old homestead land, it has proven to have significant advantages in improving water and fertilizer utilization, reducing pesticide use and improving vegetable quality, and should be vigorously promoted.

Nutrient solution replaces chemical fertilizer

In fact, substrate cultivation has long been a very mature technology; it was just difficult to promote because the substrate cost was too high.

The value of Luo Hongyi's technology lies in his having worked out materials that can be sourced locally, such as straw, cow dung and mushroom residue commonly seen in rural areas, which after high-temperature decomposition are used as substrate at low cost.

Luo Hongyi explained: “To turn them into substrate, the most important step is decomposition, that is, through fermentation to reduce the carbon-to-nitrogen ratio of the materials, while disinfecting and sterilizing, so that the substrate's properties are stable, both loose and breathable, and able to hold the plants.”

How much was the cost reduced? Li Xinye, Party branch secretary of Nanli Village, Wuli Community, Lingcheng District, Dezhou City, explained that the one-time investment in substrate, fermentation agent and integrated water and fertilizer equipment is somewhat large, at over 10,000 yuan, but it can be used for four or five years, and the nutrient solution costs about 3,000 yuan per year. Under the previous traditional soil cultivation technology, fertilizer cost more than 3,000 yuan per year, deep plowing required manual labor each year, and there were many pests and diseases, costing another two to three thousand yuan.

Easy for farmers to master

Is this technology easy for farmers to master? “Very simple.” Li Xinye said, “Spread a layer of film on the original land to separate off saline-alkali or soil-borne diseases, spread the decomposed substrate on top, then spread another layer of film to keep the substrate moist, install micro-sprinkler equipment, and you can plant the seedlings.”

But the substrate has very low nutrients, so for vegetables to grow healthily, they need nutrient solution tailored to their needs.

“Tomatoes need more calcium than eggplants; tomatoes need more nitrogen during the plant-growing stage and more potassium during the fruiting stage; the climate and water quality in Laiwu and Heze are different, so the nutrient elements need fine-tuning……” Luo Hongyi worked out his experience through continuous experimentation.

Jingwu Village is located at the mouth of the Yellow River, and most of the land is saline-alkali. Previously, even well-managed greenhouses rarely produced more than 20,000 jin of tomatoes a year. The village adopted this technology in 2013, and in 2014 the greenhouse tomato yields generally exceeded 30,000 jin.

Fangcun Town, Daiyue District, Tai'an City, has grown tomatoes for many years, and soil-borne diseases are severe. Zou Cuilian and Zou Qing of Zoujiazhuang each have a tomato greenhouse. In 2014, Zou Cuilian adopted the integrated water and fertilizer substrate cultivation technology and reached a yield of 23,000 jin; Zou Qing still used the original method and, affected by continuous cropping obstacles, produced less than 16,000 jin.

Chemical fertilizer and pesticide basically no longer used

Zou Qing said: “Years of single-crop planting not only cause severe disease, but the fertilizer utilization rate also keeps declining. As a result, more and more chemical fertilizer and pesticide are used.”

“In recent years, soil compaction, salinization and frequent disease have increasingly become obstacles to growing vegetables. Abandoning soil and using substrate can nicely avoid these problems.” Luo Hongyi said.

Zou Qing continued: “This method also saves water: watering once every six or seven days, five cubic meters of water per greenhouse each time is enough, saving 2/3 compared with before. Plus there is almost no disease, so the money for chemical fertilizer and pesticide is saved too.”

According to statistics, since the technology was promoted on a large scale in 2013, demonstration bases have been established in Daiyue District of Tai'an City, Dongying District of Dongying City, Dingtao of Heze, Lingxian of Dezhou and many other counties and cities, and success has been achieved on saline-alkali land, continuous-cropping land and reclaimed homestead land, with a cumulative demonstration area of nearly 1,000 mu. Comparative test results show that greenhouses using this technology generally reduce pesticide use by more than 80% and increase yields by about 20%, and by more than 30% on saline-alkali land.

As a major province for protected vegetable cultivation, Shandong has also accelerated the pace of promoting this technology in recent years. A major special project for the application of agricultural science and technology in the province provided 300,000 yuan to support the integration and promotion demonstration of this technology; the Provincial Department of Finance allocated 500,000 yuan in special technology promotion funds.