Effects of water and fertilizer deficit regulation with drip irrigation at different growth stages on fruit quality improvement of kiwifruit in seasonal arid areas of Southwest China

For a long time,seasonal drought occurs frequently in Southwest China,and the management of water and fertilizer in kiwifruit orchards has no quantitative standards,which seriously affects the yield and quality of kiwifruit.Therefore,the effects of water and fertilizer deficit regulation with drip irrigation(WFDRDI)on the quality of kiwifruit at different growth stages were explored to achieve water and fertilizer saving,and green and efficient production of kiwifruit.We select‘Jin Yan'kiwifruit and set two water deficit levels(W_(D20%)and W_(D40%))and three fertilizer deficit levels(F_(D15%),F_(D30%)and F_(D45%))at bud burst to leafing stage(stageⅠ),flowering to fruit set stage(stageⅡ),fruit expansion stage(stageⅢ)and fruit maturation stage(stageⅣ),respectively,with a full irrigation and fertilization as the control treatment(CK)in 2017and 2018.Results showed that the WFDRDI at stageⅡandⅢhad significant effect on fruit physical quality of kiwifruit,specifically,theⅢ-WD40%F_(D30%)andⅢ-W_(D20%)F_(D45%)treatments significantly increased fruit firmness by 13.62 and 15.59%(P<0.05),respectively;theⅡ-W_(D40%)F_(D15%)andⅢ-W_(D40%)F_(D15%)treatments significantly increased dry matter by 8.19 and 6.47%(P<0.05),respectively;theⅢ-W_(D20%)F_(D15%)treatment significantly increased single fruit weight and fruit volume by 9.33 and 12.65%(P<0.05),respectively;theⅡ-W_(D20%)F_(D15%)treatment significantly increased fruit water content by 1.99%(P<0.05).The WFDRDI had an obvious effect on fruit chemical quality of kiwifruit.TheⅢ-W_(D20%)F_(D45%),Ⅳ-W_(D40%)F_(D15%)andⅣ-W_(D20%)F_(D30%)treatments significantly increased vitamin C(Vc)content by 69.96,36.96 and 34.31%(P<0.05),respectively;theⅢ-W_(D40%)F_(D15%)andⅣ-W_(D40%)F_(D15%)treatments significantly increased total soluble solid(TSS)content by 3.79 and 17.05%(P<0.05),respectively,and significantly increased soluble sugar content by 28.61 and 34.79%(P<0.05),respectively;the contents of fructose,glucose and sucrose also had a significantly increasing trend,which was increased significantly by 5.58–19.63%,40.55–60.36%and 54.03–54.92%in theⅢ-WD40%F_(D15%)andⅣ-W_(D40%)F_(D15%)treatments(P<0.05),respectively;sugar–acid ratio was increased significantly in theⅣ-W_(D40%)F_(D15%)treatment by 64.65%(P<0.05).The degree and duration of water and fertilizer deficit had a comprehensive effect on fruit quality of kiwifruit.The WFDRDI at stageⅡandⅢcontribute to improving fruit physical quality,and the threshold of water and fertilizer deficit were 20 and 15%,respectively;stageⅢandⅣare the critical periods for improving fruit chemical quality by water and fertilizer coupling effect,and the threshold of water and fertilizer deficit were 40 and 15%,respectively.Therefore,aiming at precise water and fertilizer saving,theⅠ-W_(D20%)F_(D30%),Ⅱ-W_(D40%)F_(D15%),Ⅲ-W_(D40%)F_(D15%)andⅣ-W_(D40%)F_(D15%)treatments under WFDRDI during the whole growth period of kiwifruit were the best mode to improve quality and production of kiwifruit.

Green High-yield and High-efficiency Cultivation Techniques of Integrated Management of Water and Fertilizer for Maize under Mulch Drip Irrigation

The green high-yield and high-efficiency cultivation techniques of integrated management of water and fertilizer for maize under mulch drip irrigation are described from the aspects of high yield target of maize and its component factor indexes,pre-sowing preparation,sowing,post-sowing management,field management at the seedling stage,integrated management of water and fertilizer for target yield of maize,rational application of micro-fertilizer,comprehensive prevention and control of diseases and pests,timely harvest,etc.,in order to provide a reference for agricultural technicians,maize farmers and maize industry development in northern Xinjiang.

Integrated Monitor System of Water and Fertilizer of Greenhouse Intelligent Irrigatio

The integration of water and fertilizer is a comprehensive technology combined irrigation and fertilizer, which has outstanding advantages of saving fertilizer, saving water, saving labor, protecting environment, high yield and high efficiency. Currently, most of the water and fertilizer integrated irrigation and fertilization and irrigation operation in the production-based greenhouse is achieved relying on artificial experience, which is hard to achieve timely, scientific and intelligent irrigation. In this study, the application of STM32 embedded system realized the real-time collection of the data from the humidity sensors buried in top, middle and low depth of soil, and water and fertilizer integrated irrigation work was completed in the greenhouse through automatic control according to the predetermined fertilization and irrigation strategies for different crops. Moreover, the system had remote monitoring function, which used the global system for mobile （GSM） module to provide users with remote short message services, and therefore, the users could not only achieve the remote intelligent monitoring on the irrigation, light, ventilation of the greenhouse through short messages, but also could start and stop the remote control system operation, so as to realize the automatic management of the greenhouse environment, achieving the purpose of remote fertilization and water-saving irrigation.

Application Effect of Integrated Water and Fertilizer Technology for Tomato

Integrated water and fertilizer technology has the advantages of saving water,fertilizer and labour,which is widely applied in tomato plantation. Integrated water and fertilizer technology in topdressing and whole process of big and small tomatoes were studied,and their application effects were contrasted and analyzed,and application advantages and scopes of the two models were concluded.

Effect of water and fertilizer coupling optimization test on water use efficiency of rice in black soil regions

How to improve the water use efficiency of rice in black soil regions was studied. The black soil region in paddy fields was chosen as the research object. The research showed the fertilizer coupling mathematical model with N,P,K,irrigation water( W) and water use efficiency( WUE),which was set up under the condition of controlled irrigation with quadratic D- 416 optimized saturation design. The results show that the decending order of single factor' s influence on the WUE was N,K,P and W. All the interactions between N&P,N&K,N&W,K&P,P&W and K&W on the WUE were raised initially,and when reached a certain value,they began to decline. The decending order of each interaction on the WUE was K&P,K&W,N&K,N&P,P&W and N&W. When the WUE was targeted within 1. 8- 2. 5 kg / km^3,an optimized proportion plan was obtained in the 95% confidence interval,i. e. N 87. 76- 103. 32 kg / hm^2,K_2 O 52. 37- 66. 53 kg / hm^2 and P_2O_536. 80- 46. 71 kg / hm^2. Furthermore,the late tillering of the soil moisture content was 70. 07%- 72. 57% of the saturated moisture content.

Nitrogen and Phosphorus Loss Law and Emission Reduction Effects Under Water and Fertilizer Management Integrated Mode in Dike Paddy Field

To achieve the purpose of reducing farm non-point source pollution, we integrated site specific nitrogen management precise irrigation, controlled drainage, and wetland eco-repair system in dike area of Taihu basin. During investigation, it had given prominence for the water and fertilizer coupling effects of precise irrigation and site specific nutrient management, the characteristics of integration on controlled irrigation, controlled drainage and wetland ecosystem non-point source pollution control. Then the water and fertilizer integrated management mode of paddy field was put forward in Taihu basin where the water production efficiency increased to 1.64 kg. m-3, water saved 37.8%, fertilizer use efficiency raised 15,4%, yield raised 10%, and N, P load decreased 26%-72%. The modern agricultural and farmland ecosystems that control and cut down the farm non-point source pollution came into being, which can be a reference by Taihu basin to control its agricultural non-point source pollution and eutrophicated water body.

Effects of Seeding Rate, Water and Fertilizer Coupling on Grass Yield of Forage Millet ( Setaria itlica) in Hebei

The paper was to study the effects of seeding rate, water and fertilizer （ N, P, K） coupling on grass yield of forage millet Jigu No. 18 （Setaria itlica）. A quadratic regression otthogonal rotation combination with five factors was designed in pot experiment. The mathematical model between hay yield of forage millet （Y） and soil moisture content （ x1 ）, N fertilizer （x2 ）, P fertilizer （x3 ）, K fertilizer （x4） and seeding rate （x5 ） was established to simulate optimization. The results showed that moisture content, seeding rate, P fertilizer and K fertilizer had important effects on hay yield. Soil moisture content had the biggest impact on yield, followed by seeding rate, P and K fertilizer. The coupling effects of various factors successively were moisture content / seeding rate 〉 K fertil- izer/seeding rate 〉 N / P fertilizer 〉 soil moisture/N fertilizer 〉 soil moisture/ P fertilizer. Moreover, the mathematical model, Y = 20 543. 756 - 565. 570xI -39. 942x2 -23. 102x3 -38. 470x4 - 151. 877x5 ＋ 1. 052x^x2 ＋ 1. 604xIx3 ＋ 12. 953xt x5 - 0. 173x2x3 ＋ 0. 737x4x5 - 2. 292x5^2, was established. The optimum soil moisture and seeding rate were determined as 10% andl5 kg/hm2, respectively. In this scheme, the hay yield was 14 037. 151 0 kg/hm^2 and the economic benefit was 13 887.15 yuan/hm^2 ; the income was increased by 23.68% （ 3 288.98 yuan/hm^2 ） compared to the optimal combination in the test. The results provided a theoretical basis and technical support for forage millet production in Hebei Province.

Effects of Different Water and Fertilizer Combinations on Tree Structure,Leaf Parameters and Photosynthesis of Apple Saplings

[ Objective] This study aimed to investigate the effects of different water and fertilizer combinations on apple saplings. [ Method] ＇ Tianhong 2＇ Fuji /SH40/Malus robusta Rehd. was used as the experimental material to analyze the effects of different irrigation modes and combinations of basal fertilizer and dressing fertilizer on tree structure, leaf parameters and photosynthesis of apple saplings. [ Result] The results showed that different water and fertilizer combinations ex- hibited varying effects on tree structure, leaf parameters and photosynthesis of apple saplings. To be specific, applying 432 000 kg/hm2 basal fertilizer, 480 kg/hm2 urea and 915 kg/hmz organic fertilizer ＋ 0 ＋ 915 kg/hm2 organic fertilizer as dressing fertilizer, and 1% urea as leaf fertilizer was conducive to promoting growth of branches and leaves, increasing leaf thickness, individual leaf area and SPAD, and improving photosynthesis of apple saplings under half root irrigation and whole root irrigation conditions. In addition, the effects were more significant under whole root irrigation conditions. [ Conclusion] Selecting the appropriate water and fertilizer combination is conducive to the growth of apple saplings.

Study on the Influence of Sowing Rate,Water and Fertilizer Coupling on Water Use Efficiency of Fodder Millet

To study the influence of sowing rate,water and fertilizer( N,P and K) coupling on water use efficiency of fodder millet grown in autumn fallow field,taking " Jigu 18" as the tested material,a orthogonal rotation combination with five factors was designed in pot experiment. Results showed that both water and phosphate fertilizer had important impacts on water use efficiency,in which water had the maximum impact,followed by phosphate fertilizer,and nitrogen fertilizer,potassium fertilizer and sowing rate all had no obvious impact. Significant item of sowing rate,water and fertilizer coupling had the below sequence: potassium fertilizer + sowing rate > nitrogen fertilizer + phosphate fertilizer > water + phosphate fertilizer > water + sowing rate > water + potassium fertilizer,and other items had no obvious impact. Mathematical model was established: y = 44. 26- 1. 311x1- 2. 298x2- 3. 682x3- 6. 401x4- 34. 540x5+ 0. 273x1x3+ 0. 118x1x4+ 0. 843x1x5- 1. 948x2x3+ 6. 631x4x5. The optimal scheme taking economic benefit as the examining index was cleared,that is,soil water content maintained 10%,and sowing rate of fodder millet was 15 kg / hm2. By the scheme,water use efficiency was 26. 24 g / kg,and hay yield was13980. 90 kg / hm2,with economic benefit of 13830. 90 yuan/hm2,which was 3063. 73 yuan/hm2 more than the optimized combination with the highest hay yield,with increase magnitude of 22. 15%,and was 6215. 15 yuan / hm2 more than the optimized combination with the highest water use efficiency,with increase magnitude of 44. 94%. The research could provide theoretic basis and technical support for production practice of fodder millet grown in autumn fallow field.

Soil physical properties,nutrients,and crop yield with two-year tillage rotations under a winter wheat-summer maize double cropping system

Winter wheat and summer maize were planted from 2015-2017 to study the effects of different rotational tillage patterns on soil physicochemical properties,crop yield,water content,and fertilizer utilization.The tillage treatments were designed as wheat subsoiling-maize no tillage(WS-MN),wheat rotary tillage-maize subsoiling(WR-MS),wheat subsoiling-maize subsoiling(WS-MS),and conventional wheat rotary tillage-maize no tillage(WR-MN)as a control.Among the four treatments,WS-MN and WR-MS were single-season subsoiling treatments,and WS-MS was a two-season subsoiling treatment.The average soil bulk density decreased by 7.6%in the single-and double-season subsoiling groups compared to the WR-MN group,and the total porosity and noncapillary porosity increased by 10.7%and 12.2%,respectively.Single-or double-season subsoiling treatment was not conducive to water storage in the 0-20 cm soil layer but increased the water content of the 20-140 cm soil layer,and the average soil water content of the 0-140 cm layer was increased by 11.6%in the two-growing season treatment groups compared with the WR-MN group.In WS-MS and WS-MN groups compared with the WR-MN group,the soil ammonium nitrogen content was increased by an average of 18.6%in 0-20 cm soil and 16.8%in 20-100 cm soil;soil nitrate-nitrogen content was decreased by 13.5%in 0-100 cm soil;total organic carbon and microbial carbon contents in the 15-30 cm soil were increased by 18.1%and 12.7%,respectively;and soil urease,catalase,and alkaline phosphatase activities were increased by 46.1%,15.2%,and 23.1%,respectively.Annual crop yield and water use efficiency increased by 8.9%and 15.0%,respectively,in both the single-and double-season subsoiling treatment groups.This study demonstrated the advantages of subsoiling tillage and suggested that it is suitable for crop cultivation in the Haihe Plain,China.

Carbon sequestration and emissions mitigation in paddy fields based on the DNDC model: A review

The DeNitrification–DeComposition(DNDC)model is a process model with a series of carbon and nitrogen biogeochemistry in agro-ecosystems.It incorporates the driving factors of the ecological environment and aims to simulate the carbon and nitrogen cycle in the terrestrial ecosystem.Furthermore,the model can be applied effectively in a paddy ecosystem.Based on an investigation and literature review,this study summarized and analyzed the impact of agricultural practices such aswatermanagement,fertilizer application,and strawincorporation on greenhouse gas emissions and soil carbon storage.After years of improvement,the DNDC model can presently be used effectively to evaluate the carbon sequestration and emissions mitigation potential of various agricultural practices.However,the related details of scientific processes of agricultural management,such as biochar incorporation and plastic mulching in paddy fields,should be added or modified and combined with experimental cases of actual agricultural practices to complete the calibration of the model,provide theoretical support for its promotion,and establish a reliable method of evaluating carbon sequestration and emissions mitigation in paddy fields.