Influence of furrow irrigation regime on the yield and water consumption indicators of winter wheat based on a multi-level fuzzy comprehensive evaluation.

Irrigation regimes should be chosen to maximize crop yield and water use efficiency. To realize high yield and efficient water use with the appropriate furrow irrigation regime, the effects of two regimes (alternate furrow irrigation and conventional furrow irrigation) and three lower soil moisture limits (60, 70, and 80%) were studied on winter wheat yield and water consumption using a multi-level fuzzy comprehensive evaluation method. The results show that under the two regimes, alternate furrow irrigation and conventional furrow irrigation, when the lower limit of the soil moisture is 70%, the harvest index (0.45 and 0.39, respectively) and crop water productivity of winter wheat (1.86 and 1.90 kg m-3, respectively) are highest. The comprehensive fuzzy evaluation model considers multiple measures, including yield, harvest indices, irrigation volume, total water consumption, and crop water productivity - the index values are highest at the 70% condition, which are 0.3468 and 0.3432, respectively. Therefore, it can be concluded that a moderate water deficit is conducive to saving water resources and improving water use efficiency. In conclusion, a multi-level and multi-factor indices system of furrow irrigation regime was constructed based on ensuring winter wheat production. Conventional furrow irrigation is recommended in areas with sufficient irrigation water, while alternating furrow irrigation, which can reduce the total amount of irrigation required, is suitable for areas with water shortages.

[Effects of irrigation regimes on the variation of soil water and salt and yield of mechanically harvested cotton in Southern Xinjiang, China]. / 南疆机采棉田灌溉制度对土壤水盐变化和棉花产量的影响.

The expansion of soil salinization area is a threat to cotton production in Southern Xinjiang. How to control soil salt accumulation by developing precise irrigation strategy is currently a hot topic for the film mulching drip-irrigated cotton field. With aims for soil quality improvement and high yield, we investigated the effects of irrigation regimes on soil water and salt distribution, yield and fiber quality in major cotton production area of Southern Xinjiang. Results showed that the increase of irrigation amount contributed to a higher cotton photosynthetic product accumulation, but had no significant effect on the ratio of reproductive organs to total biomass. The degree of soil desa-lination had a positive correlation with the irrigation quotas. When the seasonal total irrigation amount exceeded 2577.83 m3·hm-2, soil salinization would not deteriorate. Irrigation amount had significant effect on WUEI, but had no effect on fiber quality. With the increasing of irrigation amount, cotton yield increased first and then decreased. In conclusion, applying 4200 m3·hm-2 seasonal irrigation amount in total and 7 d and 5 d irrigation interval for the budding and flowering stage respectively could be a suitable irrigation regime for mechanically-harvested cotton in the arid area of Southern Xinjiang.

[Modeling evapotranspiration of greenhouse tomato under different water conditions based on the dual crop coefficient method]. / åŸºäºŽåŒä½œç‰©ç³»æ•°æ³•ä¼°ç®—ä¸åŒæ°´åˆ†æ¡ä»¶ä¸‹æ¸©å®¤ç•ªèŒ„è’¸å‘è’¸è ¾é‡.

An experiment was conducted to investigate soil evaporation (E), crop transpiration (T), evapotranspiration (ET) and the ratio of evaporation to evapotranspiration (E/ET) of drip-irrigated tomato, which was planted in a typical solar greenhouse in the North China, under different water conditions [irrigation amount was determined based on accumulated pan evaporation (Ep) of 20 cm pan evaporation, and two treatments were designed with full irrigation (0.9Ep) and deficit irrigation (0.5Ep)] at different growth stages in 2015 and 2016 at Xinxiang Comprehensive Experimental Station, Chinese Academy of Agricultural Sciences. Effects of deficit irrigation on crop coefficient (Kc) and variation of water stress coefficient (Ks) throughout the growing season were also discussed. E, T and ET of tomato were calculated with a dual crop coefficient approach, and compared with the measured data. Results indicated that E in the full irrigation was 21.5% and 20.4% higher than that in the deficit irrigation in 2015 and 2016, respectively, accounting for 24.0% and 25.0% of ET in the whole growing season. The maximum E/ET was measured in the initial stage of tomato, while the minimum obtained in the middle stage. The Kc the full irrigation was 0.45, 0.89, 1.06 and 0.93 in the initial, development, middle, and late stage of tomato, and 0.45, 0.89, 0.87 and 0.41 the deficit irrigation. The Ks the deficit irrigation was 0.98, 0.93, 0.78 and 0.39 in the initial, development, middle, and late stage, respectively. The dual crop coefficient method could accurately estimate ET of greenhouse tomato under different water conditions in 2015 and 2016 seasons with the mean absolute error (MAE) of 0.36-0.48 mm·d-1, root mean square error (RMSE) of 0.44-0.65 mm·d-1. The method also estimated E and T accurately with MAE of 0.15-0.19 and 0.26-0.56 mm·d-1, and with RMSE of 0.20-0.24 and 0.33-0.72 mm·d-1, respectively.

[Coupling effect of water and nitrogen on mechanically harvested cotton with drip irrigation under plastic film in arid area of western Inner Mongolia, China.] / å† è’™å¤è¥¿éƒ¨æ—±åŒºæœºé‡‡æ£‰è†œä¸‹æ»´çŒæ°´æ°®è€¦åˆæ•ˆåº”.

In order to understand the main and interactive effects of water and nitrogen on crop growth and development, yield, fiber quality, and water-nitrogen use efficiency of mechanically harvested cotton with drip irrigation under plastic film in arid area of western Inner Mongolia, a two-factorial experiment with irrigation water amount and nitrogen dosage in completely randomized block design was conducted in Alxa Left Banner of Alxa League in Inner Mongolia. The levels of water irrigation were 216 mm (W1), 288 mm (W2) and 360 mm (W3), and the nitrogen dosages were 127.5 kg·hm-2(N1), 195 kg·hm-2(N2) and 262.5 kg·hm-2(N3). The results showed that water was the decisive factor for cotton growth, and plant height and dry matter accumulation increased rapidly with increasing the water irrigation level, but the ratio of reproductive organs to shoot biomass decreased. Compared with the treatments W1 and W2, the average boll number per plant in W3 was increased by 25.4% and 17.5%, the seed cotton yield was improved by 18.1% and 11.9%, but the single boll mass was decreased by 5.8% and 4.6%, respectively. It indicated that an increase in boll number per plant was the determining factor in achieving high seed cotton yield. Moreover, there was also a significant interactive effect between water and nitrogen affecting the seed cotton yield. Under the condition with low-level irrigation (W1 and W2), the highest seed cotton yield was measured in N1; while for the condition in W3, the seed cotton yield in N2 was greater than that in N1 and N3 by 8.5% and 31.9%, respectively. In general, the regulation of water and nitrogen had no significant effect on fiber quality. Water use efficiencyin W1N1 was 1.37 kg·m-3, which was not significantly different with the value in W3N2, and the nitrogen partial factor productivityin W3N1 was the maximum (51.35 kg·kg-1). Therefore, irrigation had a significant effect on yield increasing, but nitrogen application promoted the seed cotton yield only under well-watered conditions. The treatment with irrigation amount of 360 mm and nitrogen fertilizer of 195 kg·hm-2 could promote the shoot biomass accumulation significantly and achieve the highest seed cotton yield, and its water use efficiency and nitrogen partial factor productivity were 1.37 kg·m-3 and 36.41 kg·kg-1, respectively, indicating the potential of water-saving and yield increasing. Therefore, it was recommended as a suitable water and nitrogen management for the mechanically harvested cotton in arid area of western Inner Mongolia.

[Irrigation scheduling with a 20 cm standard pan for drip-irrigated cucumber grown in solar greenhouse in the North China Plain].

An experiment was conducted in 2013 and 2014 at the Xinxiang Comprehensive Experimental Station, Chinese Academy of Agriculture Sciences. Water amount was estimated with the Ep-20 and pan coefficient. Responses of cucumber evapotranspiration (ET), yield, quality and water use efficiency (WUE) to different drip irrigation amounts (Kcp1: 0.25; Kcp2: 0.5; Kcp3: 0.75; Kcp4: 1.0; Kcp5: 1.25) were investigated. The possibility of developing drip irrigation scheduling using the 20 cm pan was also discussed. Results showed that the seasonal evapotranspiration of cucumber ranged between 129 and 314 mm, and the water consumption generally increased with the increase in drip irrigation water amount. There was no significance difference in cucumber yield between the treatments with Kcp > 0.75, and the responses of mean fruit mass, number and length to water amount had a threshold value (0.75Ep-20). Regarding the fruit quality, the contents of total soluble solids, vitamin C and soluble sugar slightly decreased with increasing the irrigation water amount, while the soluble protein content varied in order as: Kcp2 > Kcp3 > Kcp4 > Kcp1 > Kcp5. There was a significant positive correlation (P < 0.01) between the pan evaporation and the reference crop evapotranspiration estimated based on a modified Penman-Monteith equation. In a conclusion, the drip water amount calculated with Kcp of 0.75 and the 20 cm pan were easy and feasible for cucumber cultivation in solar greenhouse in the North China Plain.

[Real-time irrigation forecast of cotton mulched with plastic film under drip irrigation based on meteorological date].

It is important to improve the real-time irrigation forecasting precision by predicting real-time water consumption of cotton mulched with plastic film under drip irrigation based on meteorological data and cotton growth status. The model parameters for calculating ET0 based on Hargreaves formula were determined using historical meteorological data from 1953 to 2008 in Shihezi reclamation area. According to the field experimental data of growing season in 2009-2010, the model of computing crop coefficient Kc was established based on accumulated temperature. On the basis of crop water requirement (ET0) and Kc, a real-time irrigation forecast model was finally constructed, and it was verified by the field experimental data in 2011. The results showed that the forecast model had high forecasting precision, and the average absolute values of relative error between the predicted value and measured value were about 3.7%, 2.4% and 1.6% during seedling, squaring and blossom-boll forming stages, respectively. The forecast model could be used to modify the predicted values in time according to the real-time meteorological data and to guide the water management in local film-mulched cotton field under drip irrigation.

[Effects of girdling on growth, yield and water use efficiency of cotton].

An experiment with girdling applied on the main stem and fruit branch during the early or flourishing stage of flowering and boll-setting was conducted to investigate the effects of different girdling treatments on the growth, yield and water use efficiency (WUE) of cotton. The results showed that compared with the control (CK), leaf area index (LAI) of girdling treatments reduced significantly and the maximum LAI of girdled cotton occurred 5-15 days in advance. Girdling reduced the shedding rate of squares and bolls significantly, and the shedding rate of squares and bolls with girdling applied on the main stem at the flourishing stage was 15.8% lower than that of CK. In contrast with CK, the seed-cotton yield and WUE increased by 24.4% and 26.7% with girdling applied on the main stem at the flourishing stage, and increased by 13.9% and 16.7% with girdling applied on the fruit branch at the early stage, respectively. However, the girdling on the fruit branch at the flourishing stage improved the seed-cotton yield and WUE insignificantly. The seed-cotton yield with girdling on the main stem at the early stage had not significant difference and its WUE reduced slightly compared with CK. It has been concluded that the girdling applied on the main stem at the flourishing stage of flowering and boll-setting could effectively reduce the abscission rate of squares and bolls, improve yield and WUE significantly, and realize the effective unity of high production and water-saving.

[Temporal and spatial variation of water requirement of winter wheat and its influencing factors in Henan Province, China].

Based on mean meteorological data of ten days in 17 observation stations from 1961 to 2012, the reference crop evapotranspiration was computed using Penman-Monteith formula recommended by FAO. The water requirement of winter wheat in Henan Province was calculated by adopting crop coefficients and the growth stage of winter wheat from the "National Irrigation Experiment Database", and the temporal and spatial distribution, variation and affecting factors in recent 51 years were analyzed by means of time-series analysis and gray relational grade analysis. The results showed that the average water requirement of winter wheat was 345-492 mm in Henan Province from 1961 to 2011, and it was lowest at Lushi station and highest at Mengjin station. The average water requirement of winter wheat was lowest from 1980 to 1989 and highest from 1961 to 1969 at most stations. The water requirement of winter wheat showed a tendency to increase with years at the 7 stations (Xinxiang, Luanchuan, Kaifeng, Xixia, Nanyang, Xinyang and Gushi) , while it indicated a tendency to decline in the other 10 stations. The water requirement of winter wheat in North Henan was higher than in South Henan, and had a high span variation in West Henan. During the growing period of winter wheat, the average daily maximum and minimum temperatures showed a tendency to increase with years, while the average daily wind speed and relative humidity, and the sunshine hours had a tendency to decline. In Henan Province, the water requirement of winter wheat was mainly affected by the average daily maximum temperature and the sunshine hours, and least influenced by the average daily relative humidity.

[Effects of irrigation threshold on soil temperature in blossom and fruit-set periods of muskmelon under mulching-drip irrigation in greenhouse].

It is very significant for muskmelon growth and production to maintain optimal conditions of soil moisture and temperature, especially during blossom and fruit-bearing periods. The object of this study was to analyze the effects of different soil water thresholds (T1: 55% of the field capacity, T2: 65% of the field capacity, T3: 75% of the field capacity, CK: 85% of the field capacity) on soil temperature under mulching-drip irrigation in greenhouse. Moreover, effects of the ratio of soil moisture to heat in the plough layer (0-20 cm) on muskmelon growth and fruit setting were investigated. Results indicated that during the flowering and fruit bearing periods, the order of mean soil temperature in the plough layer for the different treatments was T1 > T2 > T3 > CK. There was an inverse correlation between soil temperature in the plough layer and moisture. The maximum one-day variations for soil temperature on sunny day, rainy day and after irrigation were observed in the soil surface under the plastic film mulch, while the minimum happened in the soil layer of 20 cm outside the mulch. The soil temperature extreme was closely related with soil depth, and the difference in the extreme soil temperature between the soil surface and the soil layers of 10 and 20 cm was significant. The treatment T3, with the fastest plant growth rate, the minimum duration of fruit bearing and the maximum fruit setting rate, could be selected as the optimal treatment, and the ratio of soil moisture to heat in T3 was 1.62 mm · °C(-1). Therefore, taking into consideration the relationship between soil moisture and temperature during flowering and fruit bearing periods of muskmelon under mulching-drip irrigation, the ratio of soil water to heat in the plough layer should be kept at 1.62 mm · C(-1). The result would be very meaningful for drip-irrigated muskmelon production and management in greenhouse in North China.

[Optimal irrigation index for cotton drip irrigation under film mulching based on the evaporation from pan with constant water level].

A field experiment with two irrigation cycles and two irrigating water quotas at squaring stage and blossoming-boll forming stage was conducted in Urumqi of Xinjiang Autonomous Region, Northwest China in 2008-2009, aimed to explore the high-efficient irrigation index of cotton drip irrigation under film mulching. The effects of different water treatments on the seed yield, water consumption, and water use efficiency (WUE) of cotton were analyzed. In all treatments, there was a high correlation between the cotton water use and the evaporation from pan installed above the plant canopy. In high-yield cotton field (including the treatment T4 which had 10 days and 7 days of irrigation cycle with 30.0 mm and 37.5 mm of irrigating water quota at squaring stage and blossoming-boll forming stage, respectively in 2008, and the treatment T1 having 7 days of irrigation cycle with 22.5 mm and 37.5 mm of irrigating water quota at squaring stage and blossoming-boll forming stage, respectively in 2009), the pan-crop coefficient (Kp) at seedling stage, squaring stage, blossoming-boll forming stage, and boll opening stage was 0.29-0.30, 0.52-0.53, 0.74-0.88, and 0.19-0.20, respectively. As compared with the other treatments, T4 had the highest seed cotton yield (5060 kg x hm(-2)) and the highest WUE (1.00 kg x m(-3)) in 2008, whereas T1 had the highest seed cotton yield (4467 kg x hm(-2)) and the highest WUE (0.99 kg x m(-3)) in 2009. The averaged cumulative pan evaporation in 7 days and 10 days at squaring stage was 40-50 mm and 60-70 mm, respectively, and that in 7 days at blossoming-boll forming stage was 40-50 mm. It was suggested that in Xinjiang cotton area, irrigating 45 mm water for seedling emergence, no irrigation both at seedling stage and at boll opening stage, and irrigation was started when the pan evaporation reached 45-65 mm and 45 mm at squaring stage and blossoming-boll stage, respectively, the irrigating water quota could be determined by multiplying cumulative pan evaporation with Kp (the Ko was taken as 0.5, 0.75, 0.85, and 0.75 at squaring stage, early blossoming, full-blossoming, and late blossoming stage, respectively), which could be the high efficient irrigation index to obtain high yield and WUE in drip irrigation cotton field and to save irrigation water resources.

[Effects of tilage mode and deficit irrigation on the yield and water use of transplanted cotton following wheat harvest under sprinkler irrigation].

To develop a suitable tillage mode and irrigation schedule of transplanted cotton following wheat harvest under sprinkler irrigation, a field experiment was conducted to study the effects of different tillage modes (conventional tillage and no-tillage) and different irrigation schedules (45 and 22.5 mm of irrigating water quota) on the water consumption, seed yield, water use efficiency, and fiber quality of cotton. Comparing with conventional tillage, no-tillage decreased the soil evaporation among cotton plants by 20.3%. Whether with conventional tillage or with no-tillage, deficit irrigation (22.5 mm of irrigating water quota) did not affect seed yield and fiber quality, while decreased the water consumption and improved the water use efficiency. No-tillage with 22.5 mm of irrigating water quota under sprinkler irrigation not only decreased the soil evaporation effectively, but also achieved water-saving, high quality and high yield of transplanted cotton following wheat harvest.

[Estimation model for water requirement of greenhouse tomato under drip irrigation].

Based on the modified Penman-Monteith equation, and through the analysis of the relationships between crop coefficient and cumulative temperature, a new model for estimating the water requirement of greenhouse tomato under drip irrigation was built. The model was validated with the measured data of plant transpiration and soil evaporation in May 2-13 (flowering-fruit-developing stage) and June 9-20 (fruit-maturing stage) , 2009. This model was suitable for the estimation of reference evapotranspiration (ET(0)) in greenhouse. The crop coefficient of greenhouse tomato was correlated as a quadratic function of cumulative temperature. The mean relative error between measured and estimated values was less than 10%, being able to estimate the water requirement of greenhouse tomato under drip irrigation.

[Plant transpiration in a maize/soybean intercropping system measured with heat balance method].

In an experimental field with maize/soybean strip intercropping, the transpiration of maize and soybean plants was measured with sap flow gauge based on heat balance method. In the intercropping system, the diurnal change of the sap flow rates of the plants fitted single-peak curve in sunny day and multi-peak curve in cloudy day. The plant sap flow rates were affected by many environmental factors, among which, solar radiation was the most important meteorological factor. The daily sap flow per maize or soybean plant showed significant correlations with solar radiation, air temperature, relative humidity, wind speed, and soil heat flux. During the observation period (June 1-30, 2008), the mean daily transpiration of maize plant (1.44 mm x d(-1)) was about 1.8 times of that of soybean plant (0.79 mm x d(-1)). Maize transpiration and soybean transpiration contributed 64% and 36% to the total transpiration of the intercropping system, respectively. Due to the spatial variation of stem diameter and leaf area, it would be necessary to install more sap flow gauges to accurately measure the sap flow of maize and soybean plants.

[Effects of soil moisture regime on greenhouse tomato yield and its formation under drip irrigation].

Field plot experiment was conducted to study the effects of soil moisture regime at different growth stages on the fruit size, fruit number, percentage of malformed fruit, and yield formation of greenhouse tomato under drip irrigation, and the relationships between tomato yield and irrigation amount. Moderate soil water deficit (50%-55% of field capacity) at tomato's seedling stage increased the fruit number but reduced the fruit size, decreased the percentage of malformed fruit, and made the fruit maturation mainly concentrated in later picking period. Severe water deficit (less than 65% of field capacity) at flowering and fruit-developing stages promoted fruit maturation, but decreased fruit number and increased the formation of small and malformed fruits. The soil moisture content higher than 80% or lower than 65% of filed capacity at fruit maturation stage less affected fruit maturation but decreased fruit yield, and lower than 65% of filed capacity also decreased the fruit number and increased the percentage of malformed fruit. No significant effects of irrigation amount on fruit maturation were observed. The correlations of tomato yield and its water use efficiency with irrigation amount could be well described by quadratic function. The fruit number and total yield were higher while the percentage of malformed fruit was lower when the soil moisture content was controlled at 60%-65% of field capacity at seedling stage, 70%-75% of field capacity at flowering stage, and 70%-75% of field capacity at fruit-developing stage, which could be used as the optimal soil moisture indices for the greenhouse tomato production under drip irrigation.

[Spatiotemporal distribution patterns of winter wheat and spring maize root systems under intercropping].

In this paper, root samples of winter wheat and spring maize under intercropping were taken with large-bore soil auger, and the dynamics of their spatiotemporal distribution were studied. The results showed that both in vertical and in horizontal directions, the root mass of winter wheat decreased in power function, while that of spring maize decreased in exponent function. Multiple linear regression was made to establish the two-dimensional spatiotemporal distribution functions of intercropped winter wheat and spring maize root biomass, and the validation tests demonstrated that theses functions were available to describe the real growth status of test crops root systems.