201. The impact of agricultural irrigation with reclaimed water on growth of Chinese cabbage and cotton.

• Authors:
  • Chen, X.
  • Zhang, T.
  • Chen, G.
  • Chen, Z.
  • Chen, X.
  • Zhang, T.
  • Chen, G.
  • Chen, Z.
• Source: Xinjiang Agricultural Sciences
• Volume: 49
• Issue: 5
• Year: 2012
• Summary: Objective: Study the feasibility of secondary treated waste water for agricultural irrigation in Urumqi. Method: Chinese cabbage and cotton were used as experimental materials and treated respectively with treatment 1 which is control, treatment 2 which is 50% reclaimed water, and treatment 3 which is 100% reclaimed water. POD, CAT, SOD, MDA, and dry weight of Chinese cabbage and production of cotton were detected. Result: Results showed that inhibitory effects of reclaimed water were proportional to the treatment duration and concentration. The dry weight of 50% reclaimed water treated treatment 1, as the order treatment 2 > treatment 1 > treatment 3. Because the nutrients and harmful substances respectively played promotion and inhibition on the growth of Chinese cabbage, treatment 2 growed better; The yields per acre of cotton under three kinds treatments were significant difference, as the order treatment 1 > treatment 2 > treatment 3, that means reclaimed water inhibits the growth of cotton. Conclusion: Reclaimed water showed different effects on different crops. On cabbage, it mainly showed promotive effect, while on cotton, it mainly showed inhibition effect.

202. Design and Implementation of an Irrigation Decision Support System for Cotton in Xinjiang, China

• Authors:
  • Li, Y.
  • Cao, W.
  • Lei, X.
  • Chen, D.
• Source: Sensor Letters
• Volume: 10
• Issue: 1-2
• Year: 2012
• Summary: CIDSS, an irrigation decision support system (DSS), was developed to satisfy the need for drip irrigation under plastic film of cotton yield management in Xinjiang, China. It is compartmentalized into four main modules: database management, real-time moisture diagnosis, real-time irrigation decision making, and production management decisions. The present study used the Kriging interpolation method to estimate soil moisture caused by spatial variability. The Least Squares Support Vector Machines (LSSVM) model and an empirical model based on the exponential depletion relation of soil moisture were also employed to predict soil moisture. A cotton production management expert system was realized by embedding C Language Integrated Production System. By integrating the interfaces of the moisture sensor, the automatic meteorological station in the field, and the solenoid valve control system, the present study solved the problem of the data for real-time decision making. Finally, the use of CIDSS was demonstrated through characteristic case studies on cotton areas in Xinjiang Uygur Autonomous Region, China.

203. Cotton salt tolerance appraisal indices and eigenvalue under border irrigation with saline water.

• Authors:
  • Liu, Z.
  • Li, K.
  • Cao, C.
  • Zheng, C.
  • Sun, J.
  • Zhang, J.
  • Feng, D.
• Source: Transactions of the Chinese Society of Agricultural Engineering
• Volume: 28
• Issue: 8
• Year: 2012
• Summary: In order to use the mineralized shallow groundwater to relieve the crisis of freshwater resources shortage, the 5 years field experiment under border irrigation with mineralized water before sowing was conducted. The response relations among different salt stress levels and cotton growth index and seed cotton yield were analyzed in this study, and the cotton salt tolerance appraisal indices and eigenvalue under border irrigation with different saline water before sowing were put forward. The results showed that the relative emergency rate, relative plant height, relative leaf area, relative above-ground dry matter mass, relative fruit branch number, relative boll number and relative maximum of buds, flowers and bolls all could be used as salt tolerance appraisal indices of cotton. The relative height was recommended as the most practical salt tolerance appraisal index among them because it was easy to observation and sensitive to salt stress. The salinity of irrigation water should be below 5.48 g/L when the yield of seed cotton in saline water treatment was consistent with the fresh water irrigation treatment after a 5-year continuous irrigation.

204. Soil organic carbon dynamics in a dryland cereal cropping system of the Loess Plateau under long-term nitrogen fertilizer applications.

• Authors:
  • Liu, W. Z.
  • Li, Y.
  • Zhu, H. H.
  • Coleman, K.
  • Wu, J. S.
  • Guo, S. L.
• Source: Plant and Soil
• Volume: 353
• Issue: 1/2
• Year: 2012
• Summary: Aims: Concerns over food security and global climate change require an improved understanding of how to achieve optimal crop yields whilst minimizing net greenhouse gas emissions from agriculture. In the semi-arid Loess Plateau region of China, as elsewhere, fertilizer nitrogen (N) inputs are necessary to increase yields and improve local food security. Methods: In a dryland annual cropping system, we evaluated the effects of N fertilizers on crop yield, its long-term impact on soil organic carbon (SOC) concentrations and stock sizes, and the distribution of carbon (C) within various aggregate-size fractions. A current version (RothC) of the Rothamsted model for the turnover of organic C in soil was used to simulate changes in SOC. Five N application rates [0 (N0), 45 (N45), 90 (N90), 135 (N135), and 180 (N180) kg N ha -1] were applied to plots for 25 years (1984-2009) on a loam soil (Cumulic Haplustoll) at the Changwu State Key Agro-Ecological Experimental Station, Shaanxi, China. Results: Crop yield varied with year, but increased over time in the fertilized plots. Average annual grain yields were 1.15, 2.46, 3.11, 3.49, and 3.55 Mg ha -1 with the increasing N application rates, respectively. Long-term N fertilizer application increased significantly ( P=0.041) SOC concentrations and stocks in the 0-20 cm horizon. Each kilogram of fertilizer N applied increased SOC by 0.51 kg in the top soil from 1984 to 2009. Using RothC, the calculated annual inputs of plant C (in roots, stubble, root exudates, etc.) to the soil were 0.61, 0.74, 0.78, 0.86, and 0.97 Mg Cha -1 year -1 in N0, N45, N90, N135 and N180 treatments, respectively. The modeled turnover time of SOC (excluding inert organic C) in the continuous wheat cropping system was 26 years. The SOC accumulation rate was calculated to be 40.0, 48.0, 68.0, and 100.0 kg C ha -1 year -1 for the N45, N90, N135 and N180 treatments over 25 years, respectively. As aboveground biomass was removed, the increases in SOC stocks with higher N application are attributed to increased inputs of root biomass and root exudates. Increasing N application rates significantly improved C concentrations in the macroaggregate fractions (>1 mm). Conclusions: Applying N fertilizer is a sustainable practice, especially in carbon sequestration and crop productivity, for the semiarid Loess Plateau region.

205. Effects of Chinese cabbage nitrogen application rate on Chinese cabbage yields, nitrogen utilization, nitrate accumulation (soil & cabbage) of potato - Chinese cabbage double cropping system.

• Authors:
  • Fan, M. S.
  • Hao, Y. F.
  • Hu, B.
• Source: China Vegetables
• Issue: 10
• Year: 2012
• Summary: The effects of Chinese cabbage N application rate on Chinese cabbage yields, nitrogen utilization, nitrate contents, and nitrate nitrogen accumulation in soil were studied under potato-Chinese cabbage double cropping system in Hetao irrigated area of Inner Mongolia with 5 N application rates at Chinese cabbage planting season. The results showed that the yields and the double cropping net economic returns were the highest with the Chinese cabbage N application rate of 120 kg.hm -2; the double cropping system N accumulation and N recovery ratio were enhanced at the total N application rate from 225 kg.hm -2 to 405 kg.hm -2, compared with that of the conventional mono potato production in the open field at the N application rate of 225 kg.hm -2; the nitrate contents in Chinese cabbage and the nitrate accumulations within 0-160 cm soil profiles were increased with the increscent N applied rates. At the Chinese cabbage N application rate was ≥120 kg.hm -2, the nitrate contents in Chinese cabbage reached a high level, and the nitrate accumulations within 0-160 cm soil profiles were ≥162 kg.hm -2, hence the risk of nitrate contamination in underground water was increased for autumn irrigation. Reasonable N application rate had an effective effects on reducing nitrate contamination in groundwater, reducing nitrate content in Chinese cabbage, and increasing net economic return.

206. Optimization of the irrigation water resources for agricultural sustainability in Tarim River Basin, China

• Authors:
  • Ma, Y. G.
  • Chen, X.
  • Li, Y. P.
  • Huang, Y.
• Source: Agricultural Water Management
• Volume: 107
• Year: 2012
• Summary: An integrated optimization method is developed for supporting agriculture water management and planning in Tarim River Basin, Northwest China. The developed method couples two-stage stochastic programming (TSP) with inexact quadratic program (IQP). The hydrological model is provided for forecasting the available irrigation water. The simulation system is then embedded into an optimization framework, where the objective is to maximize the system benefit for water resources management. The developed method can not only deal with nonlinearities in the cost/benefit objective and uncertainties expressed as probabilities and intervals, but also support the analysis of policy scenarios that are associated with economic penalties when the promised water-allocation targets are violated. A case study is conducted for Kaidu-kongque watershed in Tarim River Basin. The results obtained can help generate desired policies for water resources management with maximized economic benefit and minimized system-failure risk. (C) 2012 Elsevier B.V. All rights reserved.

207. Effects of different water levels on cotton growth and water use through drip irrigation in an arid region with saline ground water of Northwest China

• Authors:
  • Liu, S.
  • Jiang, S.
  • Hu, W.
  • Wan, S.
  • Wang, R.
  • Kang, Y.
• Source: Agricultural Water Management
• Volume: 109
• Year: 2012
• Summary: Due to the mismanagement of water and fertilizer application, cotton cultivation in Xinjiang Northwest China is faced with the problems of soil deterioration and groundwater table ascension. This study was conducted to evaluate the effects of different levels of water applied through drip irrigation on cotton yield and water use in an arid region of Northwest China. The experiment included five water treatments in which the soil matric potential (SMP) at a depth of 20 cm was controlled higher than -10 kPa (S1), -20 kPa (S2), -30 kPa (S3), -40 kPa (S4), and -50 kPa (S5) after cotton was established. The results revealed that the highest cotton evapotranspiration (ETc) was achieved under S1 (-10 kPa) treatment and the ETc, deep percolation and the ratio of deep percolation with irrigation water all increased with increasing SMP threshold. After three years experiment, no salt accumulation in surface soil layer was found under our irrigation schedule. The highest seed cotton yield was obtained when the SMP threshold was controlled above -30 kPa in 2008, and -20 kPa in 2009 and 2010. Moreover, the highest yield obtained after 3 years was 42% higher than the average yield achieved by local farmers in the area. Additionally, the water use value (WUE and IWUE) tended to increase as the SMP threshold decreased in 2009 and 2010. Considering the cotton yield and the impact of irrigation on the underground water table, an SMP higher than -20 kPa at 20 cm can be used as an indicator for cotton drip irrigation scheduling and agronomic practices in this area to help alleviate the dangerous increase in the water table while increasing the cotton seed yield. (C) 2012 Elsevier B.V. All rights reserved.

208. The Indus basin in the framework of current and future water resources management.

• Authors:
  • Vanham, D.
  • Laghari, A. N.
  • Rauch, W.
• Source: Hydrology and Earth System Sciences
• Volume: 16
• Issue: 4
• Year: 2012
• Summary: The Indus basin is one of the regions in the world that is faced with major challenges for its water sector, due to population growth, rapid urbanisation and industrialisation, environmental degradation, unregulated utilization of the resources, inefficient water use and poverty, all aggravated by climate change. The Indus Basin is shared by 4 countries - Pakistan, India, Afghanistan and China. With a current population of 237 million people which is projected to increase to 319 million in 2025 and 383 million in 2050, already today water resources are abstracted almost entirely (more than 95% for irrigation). Climate change will result in increased water availability in the short term. However in the long term water availability will decrease. Some current aspects in the basin need to be re-evaluated. During the past decades water abstractions - and especially groundwater extractions - have augmented continuously to support a rice-wheat system where rice is grown during the kharif (wet, summer) season (as well as sugar cane, cotton, maize and other crops) and wheat during the rabi (dry, winter) season. However, the sustainability of this system in its current form is questionable. Additional water for domestic and industrial purposes is required for the future and should be made available by a reduction in irrigation requirements. This paper gives a comprehensive listing and description of available options for current and future sustainable water resources management (WRM) within the basin. Sustainable WRM practices include both water supply management and water demand management options. Water supply management options include: (1) reservoir management as the basin is characterised by a strong seasonal behaviour in water availability (monsoon and meltwater) and water demands; (2) water quality conservation and investment in wastewater infrastructure; (3) the use of alternative water resources like the recycling of wastewater and desalination; (4) land use planning and soil conservation as well as flood management, with a focus on the reduction of erosion and resulting sedimentation as well as the restoration of ecosystem services like wetlands and natural floodplains. Water demand management options include: (1) the management of conjunctive use of surface and groundwater; as well as (2) the rehabilitation and modernization of existing infrastructure. Other demand management options are: (3) the increase of water productivity for agriculture; (4) crop planning and diversification including the critical assessment of agricultural export, especially (basmati) rice; (5) economic instruments and (6) changing food demand patterns and limiting post-harvest losses.

209. Development of automatic control device for integrated water and fertilization drip irrigation of citrus orchard.

• Authors:
  • Chen, S.
  • Yue, X. J.
  • Feng, R. J.
  • Hong, T. S.
  • Li, J. N.
• Source: Transactions of the Chinese Society of Agricultural Engineering
• Volume: 28
• Issue: 10
• Year: 2012
• Summary: To realize automatic control of integral control of water and fertilization under drip irrigation for citrus with independent water tank and liquid fertilizer tank, a timing control device powered with battery for controlling drip irrigation and fertigation was developed. The device was composed of two solenoid valves which were used to control the order and time of water or liquid fertilizer flowing into the drip irrigation pipe network respectively. To extend battery life, sleep mechanism and power management technology were used with the quiescent current of the device less than 11.2 A. The device was tested in actual application for six consecutive months, and the results showed that the controller was stable and reliable, and the battery voltage dropped only from the initial value of 9.35 to 8.50 V. The device was simple to use, and it can control not only the drip irrigation integration of water and fertilizer, but water drip irrigation. In addition, the rotation irrigation can be carried out by combining multiple devices, and then can control a larger irrigation area. So the device developed in this research is practical and has good promotion prospects.

210. Effects of drip irrigation with plastic mulching on the net primary productivity, soil heterotrophic respiration, and net CO2 exchange flux of cotton field ecosystem in Xinjiang, Northwest China.

• Authors:
  • Jiang, L.
  • Yan, Z. Y.
  • Lai, D. M.
  • Zhang, R. H.
  • Li, Z. G.
  • Tian, C. Y.
• Source: Ying Yong Sheng Tai Xue Bao
• Volume: 23
• Issue: 4
• Year: 2012
• Summary: In April-October, 2009, a field experiment was conducted to study the effects of drip irrigation with plastic mulching (MD) on the net primary productivity (NPP), soil heterotrophic respiration (Rh) , and net CO2 exchange flux (NEF(CO2)) of cotton field ecosystem in Xinjiang, taking the traditional flood irrigation with no mulching (NF) as the control. With the increasing time, the NPP, Rh, and NEF(CO2) in treatments MD and NF all presented a trend of increasing first and decreased then. As compared with NF, MD increased the aboveground and belowground biomass and the NPP of cotton, and decreased the Rh. Over the whole growth period, the Rh in treatment MD (214 g C x m(-2)) was smaller than that in treatment NF (317 g C x m(-2)), but the NEF(CO2) in treatment MD (1030 g C x m(-2)) was higher than that in treatment NF (649 g C x m(-2)). Treatment MD could fix the atmospheric CO2 approximately 479 g C x m(-2) higher than treatment NF. Drip irrigation with plastic mulching could promote crop productivity while decreasing soil CO2 emission, being an important agricultural measure for the carbon sequestration and emission reduction of cropland ecosystems in arid area.