Screening Test of Water-soluble Fertilizers for Watermelon(Citrullus lanatus)

[Objectives] This study was conducted to find water-soluble fertilizers( WSFs) suitable for watermelon cultivation in Hainan area.[Methods] The effects of three WSFs on watermelon yield and quality were studied.[Results]Fahai·Jiabao WSF improved watermelon yield by 7.87% compared with the CK,and showed a net increase of income of 538.4 yuan/667 m^2.And it could significantly improve soluble sugar,Vc and protein contents,and could effectively reduce nitrate content.[Conclusions]Fahai·Jiabao WSF is the optimal WSF for integration of water and fertilizer,and has the market prospect of large-area application and extension.

Evaluation of Application Effect of Silicon-containing Water-soluble Fertilizer on Fast Vegetables

[Objectives]The study aims to verify the application effect of silicon-containing water-soluble fertilizer on fast vegetables.[Methods]Two vegetable crops,rape and lettuce,were studied,and three treatments were set up,including treatment 1(conventional fertilization+foliar spraying of silicon-containing water-soluble fertilizer,treatment 2(conventional fertilization+foliar spraying of the same amount of clear water),and treatment 3(conventional fertilization).[Results]The yield of lettuce and rape in treatment 1 increased by 15.1%and 8.6%,respectively;compared with treatment 3,the yield of lettuce and rape rose by 18.6%and 10.9%,respectively.Variance analysis shows that the F values of lettuce and rape were 20.938 and 35.372,respectively,and the differences among various treatments were extremely significant.[Conclusions]The application of silicon-containing water-soluble fertilizer on lettuce and rape significantly increased their yield.

Responses of Wheat Production, Quality, and Soil Profile Properties to Biochar Applied at Different Seasons in a Rice-Wheat Rotation

In the rice-wheat rotation system,biochar(BC)can be applied at the initiation of the rice or wheat season.Here,we compared the effects of BC that were applied at two different crop seasons on wheat production,quality,and soil profile properties in a rice-wheat rotation system with nitrogen(N)fertilizer applied at 280 kg/ha rate.Results showed that both wheat grain production and N recovery use efficiency were influenced by BC applied at two crop seasons.Biochar application did not affect the total non-essential amino-acid,but when applied during wheat season,BC significantly(p<0.05)increased total essential amino acid in grain by 12.3%,particularly for the valine(+48.2%),methionine(+43.8%),and isoleucine(+10.3%).We found that BC significantly(p<0.05)decreased the pH of soil at 0–6 cm and 20–30 cm by 0.14–0.18 and 0.05–0.08 units,respectively.The NH4+-N content of the whole observed soil profile were reduced by BC application,however,the effect of BC on NO3–-N content varied with the application season and profile depth.Interestingly,BC applied at wheat and rice season significantly(p<0.05)improved topsoil N contents by 48.4%and 19.7%,respectively.In addition,data suggested that BC applied during wheat season performed better in enhancing soil available phosphorus,potassium,and organic matter contents.In conclusion,we suggest that the optimum application time of BC for enhancing crop production and quality(take amino-acid content for example)and improving soil fertility is at the initiation of the wheat season.

Toxicity evaluation of collagen hydrolysates from chrome shavings and their potential use in the preparation of amino acid fertilizer for crop growth

Resource utilization of chrome shavings(CS)has attracted a lot of attention from scientists and technologists in leather industry.Especially,the collagen hydrolysates extracted from CS are expected to find potential application values in agricultural field.However,there is no biotoxicity analysis of collagen hydrolysates from CS.Herein,the collagen hydrolysates with different molecular weights were produced from CS by three hydrolysis dechroming methods including alkaline hydrolysis,enzymatic hydrolysis and alkaline-enzymatic synergistic hydrolysis,and the optimal hydrolysis process of CS was designed and conducted.To evaluate their toxicity,the three collagen hydrolysates were formulated into a nutrient solution for zebrafish development.The obtained results indicated that the hydrolysates with low concentrations(less than 0.6 mg/mL)were safe and could promote the development for zebrafish embryos.Furthermore,the three collagen hydrolysates were utilized as organic nitrogen sources and formulated into amino acid water-soluble fertilizers(AAWSF)including alkaline type fertilizer(OH),enzymatic type fertilizer(M)and alkaline-enzymatic type fertilizer(OH-M)for the early soilless seeding cultivation of wheat,soybean and rapeseed.It is worth mentioning that the chromium contents in the prepared AAWSF were less than 10 mg/kg,which is far less than the limit value in the standard(China,50 mg/kg).The growth and development of seedlings(germination rate,plant height,fresh weight of leaves,soluble sugar content and chlorophyll content)were investigated.The corresponding results showed that the growth of seedlings watered with AAWSF was better compared with the other treatments,and the OH-M fertilizer had the best promoting effect on the seedlings growth and development,followed by the M and OH fertilizers.The safe toxicity assessment of the collagen hydrolysates will expand their application scope,and the use of collagen hydrolysates extracted from CS for seedlings growth also provides an effective and reason-able way to deal with the chromium-containing leather solid waste,which is an effective way to realize its resource utilization.