Effects of Dongshengbao Liquid Organic Fertilizer on Soil Improvement of Continuous Cropping Cucumber

Yanan LIU, Chuntao QIAN, Shohret Maujude Daulet

1. New Rural Development Research Institute of NJAU(Changshu), Changshu 215534, China

2. Changshu Dongshengbao Rewnewable Resources Co, Ltd., Changshu 215534, China

In recent years, protected cultivation has become one of the leading industries in agricultural production in China because of its high compound index, high yield and stable production throughout the year[1],which not only bring convenience to people’s life, but also generates generous incomes to farmers. Through the investigation of vegetable cultivation in Dongdun Village of Dongbin Town in Changshu, we found that cucumber is one of the major vegetables,as it is planted on more than 80% of local cultivated land. However, along with the increasing practices in the protected cultivation, there have been various kinds of problems,such as different degrees of soil salinization, soil acidification, physiological disease,yield and quality decreasing, which seriously affects vegetable yield and farmers’ benefits. This is a major problem to be addressed in the vegetable yield at present[2].

Although there are many reports regarding the influences of organic fertilizer to the soil nature and crops yield in China and abroad[3-7], there is no study on the effects of fertilizers on soil nature, vegetable growth and nutrition quality. Dongbing in Changshu has 20 years of plantation history, and 26 000 hm2of plantation area is one of the most important unharmful vegetable supply in south Jiangsu.Takingthe protected vegetables in Dongbing in Changshu as the study subject, we planted cucumber in continuous croppings. By measuring the soil EC, pH,N, P and K content, this paper examines the effects of organic fertilizer on the soil improvement of cucumber,determines the changes of the strain height, the dry weight of the aboveground part, and leaf area, and explores the effects of organic fertilizer on the growth of cucumber,which provides a certain scientific references to the soil improvement based on liquid organic fertilizer.

Materials and Methods

Test materials

The experiment is carried out in the greenhouse of modern agricultural industry in Dongbing Town in Changshu. The greenhouse plantation has continued for eight years.The soil was clay loam. The pH of soil physical property was 5.87, soil electricity conductivity rate was 1.29 mS/cm.The total nitrogen was 19.44 mg/kg, and the total phosphorus was 57.60 mg/kg.The total potassium was 213.17 mg/kg.The organic content was 0.3%.

The tested organic fertilizer was provided by Changshu Dongshengbao Renewable Resources Scientific and Technological Co., Ltd. The fertilizer was the organic soil solutions with amino acid as the main components.The basic features of the organic solution of microorganism was pH 4.66,EC 6.51 mS/cm, organic matter 3.0%,total nitrogen 115 mg/kg, total phosphorus 91.04 mg/kg,and total potassium 6 069 mg/kg.The basic features of the diluted organic fertilizer was pH 5.12, EC 0.83 mS/cm, organics 1.0%,total nitrogen 56.60 mg/kg,total phosphorus 53.80 mg/kg and total potassium 3084.00 mg/kg.

Test methods

Cucumber seeds were put into the water to accelerate germination.The Nanshui No.2 cucumber seeds at first were put into the 55 ℃water for five hours before being thrown into the incubator at 28 ℃. When all seeds showed 80% germination, seeds which grew at similar stage were put into the nutrition box, one seed at a box. Then, cucumber seedlings were transplanted when there were three to four leaves in the plants.

October 28thwitnessed the addition of evenly mixed soil into 48 pots for transplantation.The flower pot was 26 cm long in the upper mouth, 19 cm long in the lower mouth and 20 cm long in the height. 5 000 cm3of soil was added into each pot. There were three treatments for the experiment.For treatment 1, no fertilizer was applied as the base fertilizer. In terms of treatment 2, Stanley compound was taken as the base fertilizer. With regard to treatment 3, the micro organic fertilizer which has been diluted for 20 times was considered as the base fertilizer. There were 16 pots in each treatment. The base fertilizer in treatment 2 and 3 were applied into the flower pot. The fertilizer in treatment 2 was 1.3 g per pot (as it was 450 kg/hm2)[9]. In treatment 3, the stock solution was diluted for 20 times,and 800 ml/pot of fertilizer was applied(according to the service manual). In treatment 1, plants were watered with 800 ml water. Cucumbers were transplanted on November 3, 2014. No fungicide and chemical materials were used. Foliar fertilizer was applied. In order to guarantee the appropriate temperature for the growth of cucumber, we used the membrane for its growth.

Sampling and analysis method

In the early flowering period, we studied the incidence of cucumber,and each treatment was investigated.The grade standard was like this:grade 0, no incidence; grade 1, less than one fourth of leaves being sick;grade 2, less than a half of leaves being sick; grade 3, less than three fourths of leaves being sick; grade 4,more than three fourths of leaves being sick.

In the early fruiting period,we collected three pots which grew the best from each treatment to measure the strain height, the leaves area and the dry weight above the ground. The strain height of the aboveground part was measured with 30 cm ruler. YMJA leaves determiner was applied to measure the leaves area of the third leaves on each strain, and the dry weight of the aboveground part was measured with electronic balance.

Before transplanting and in the early fruiting stage, we collected three pots which grew the best from each treatment to measure the salt in the soil, pH, the amount of nitrogen and phosphorus in the soil. 0 to 10 cm of soil samples were collected from the soil collector, and the diameter of the soil collector was 3.2 cm. Nine soil samples were put into the oven to dry at a temperature of 40 ℃.The EC value was determined by the convertible electronic conductor (Shanghai electronic conductor, DDB-303A). Soil pH was measured by the pH meter(HANNA, HI98128). The N, P, K content in the soil was determined by the soil nutrition (Zhejiang Tuopu, TYP-6PC).

Data process

The data was analyzed for significant differences at the level of P＜0.05 by SPSS11.0.

Table 1 Effects of different fertilizing treatments on the EC value and pH of soil

Results and Analyses

Effects of different fertilizer treatments on the EC value,pH and nutrition of soil

Effects of different fertilizer treatments on the EC value and pH As we can see from Table 1,the EC value of organic fertilizer and compound fertilizer differed greatly.The EC value of potted soil which was treated with organic fertilizer was 0.93 mS/cm, which was 27.91% less than the potted soil.The EC value of potted soil which was treated with compound fertilizer was 1.53 mS/cm, which was 18.6% higher than that of the control potted soil.This means that the organic fertilizer in the potted soil can decrease the soluble saline content in the soil, while the compound fertilizer in the potted soil increased the soluble saline as it intensified the salinization in the soil.

Table 2 Effects of different fertilizer treatments on the soil nutrition contents

Table 3 Effects of different fertilizer treatments on the growth of cucumber during the early stage

Table 4 Effects of different fertilizer treatments on the cucumber diseases

Furthermore, we can see that the pH in the potted soil which have been fertilized with organic fertilizer and applied compound was at 0.05 level.The pH value of the pot soil which was applied with organic fertilizer was 5.89,which was 0.86%higher than the controlled soil. The pH of the potted soil which was treated with compound fertilizer was 5.09, which was 12.84%less than the pH in the potted soil.This suggested that the organic fertilizer can ease the acidification in the soil,and the application of compound fertilizer can intensify the acidification in the soil.

Effects of different treatments on the nutrition in the soil According to Table 2, the total nitrogen and potassium in the potted soil which have been treated with organic fertilizer and compound fertilizer was at 0.05 level. The total nitrogen in the potted soil which was treated with organic fertilizer was 25.33 mg/kg, which was 30.30% higher than the control. The total nitrogen in the potted soil which was treated with compound fertilizer was 73.33 mg/kg,which was 277.21%higher than the control.The potassium in the potted soil which was treated with organic fertilizer was 247.67 mg/kg,which was 16.18% higher than the control.The total potassium in the potted soil which was treated with 699 mg/kg, which was 227.14% higher than the control. As we can see, the nutrition in the soil which was treated with organic fertilizer increased little,and the remaining nutrition in the soil was low.The nutrition in the potted soil which was treated with compound fertilizer increased little, and the remaining nutrition in the soil was high, which resulted in soil salinization.

The amount of total phosphorus in the potted soil which was treated with organic fertilizer was 92 mg/kg,59.72% higher than the control, while the amount of the total phosphorus in the potted soil treated with compound fertilizer was 144.8 mg/kg, which was 151.39% higher than the control. This suggested that after applying the two kinds of fertilizers, the total phosphorus in the soil rose, which might be related to the growth of cucumber.

Effects of different fertilizer treatments on the continuous cropping of cucumber

Effects of different fertilizing treatments on the growth of cucumber during the early stage As we can see from Table 3, the difference between strain and heights dry weight of the aboveground part of the potted cucumber which was treated with organic fertilizer and compound fertilizer were significant at the level of 0.05.The dry weight of the aboveground part and the strain height was 2.49 and 24.53 cm respectively, which was 283.08%and 242.12%higher than the control. The dry weight of the aboveground part and the strain height of the plants treated with compound fertilizer was 0.86 g and 4.5 cm, which was 32.31% and -37.24% higher than the control respectively.Results prove that the organic fertilizer can promote the accumulation of aboveground parts and the increase in the strain height,and the promotion effects were obviously better than the compound fertilizer treatment.

The numerical value of the leaf areas of cucumber treated with organic fertilizer was insignificantly different from the one treated with compound fertilizer. The leaf area of the cucumber treated with organic fertilizer was 65.67 cm2, which was 254.02% higher than the control. The leaf area of the cucumber treated with compound fertilizer was 23.41 cm2, which was 26.20% higher than the control. The organic fertilizer promoted the cucumber leaf area during the early fruiting stage, and the effect was better than the compound fertilizer treatment.

Effects of different fertilizer treatments on the cucumber in the flowering stage According to Table 4,the incidence rank of the cucumber treated with organic fertilizer was all below grade 2, while the incidence rank of the cucumber treated with compound fertilizer were all above grade 2, among which 11 pots reached grade 4. This suggested that the organic fertilizer contributed to the lowering the cucumber incidence.

Discussions

One of the main disadvantages of continuous cropping was the secondary soil salinization which was caused by the application of large amounts of fertilizer. At present, the main measures to diminish the shortcomings brought by the continuous cropping was the reasonable rotating plantation, soil salinization and increasing application of organic fertilizer, etc. The approach of applying organic fertilizer is widely adopted. Cucumber, as one of the major vegetables planted in China,can be found on more than 0.6 million hm2, which created above 1 billion economic benefits.The organic fertilizer could solve theproblems of soil salinization and soil acidification of continuous cropping,improve the resistance ability of Didymella bryoniae and promote the plant growth.

The rapid increase in the phosphorus content in the soil after applying organic fertilizer and compound fertilizer might be related to the necessity of fertilizer in the growth of cucumber. At the early stage, there are not much needs of phosphorus in the growth of cucumber. The content of total phosphorus in the fertilizer cannot meet the growth of plants, which lead to the insufficient use of phosphorus.

The test also measured the soil capacity in three treatments. The soil capacity reflected the soil texture and organic content. The looser the soil texture, the higher organic content,and the lighter the soil bulk density,and vice versa. Through determination, the soil bulk density of organic fertilizer was 1.53,1.52 and 1.54 g/cm3,which showed that the soluble organic fertilizer did not have any effects on lowering the soil bulk density. This might because the applied amount and duration were limited.Whether organic fertilizer can improve the soil bulk capacity needs further investigation.

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