Effect of water saving management practices and nitrogen fertilizer rate on crop yield and water use efficiency in a winter wheat–summer maize cropping system

Deficit irrigation (DI) is a water-saving irrigation strategy in which irrigation water is applied at amounts less than full crop-water requirements. Some researchers have suggested that greater increases in water use efficiency (WUE) could be realized if DI was used in combination with water conservation or rainwater harvesting techniques. The objective of this six-year field study was to determine the effect of DI in combination with straw mulch (SM) or plastic film-mulched ridge and straw-mulched furrows (RF) on grain yield and WUE in a winter wheat-summer maize rotation. Interactive effects between the water-saving management practices and N fertilizer rate were also investigated. Results indicated that maize yields in the RF + DI and SM + DI treatments were as much as 1.6 times those in the DI and conventional furrow irrigation (CFI) treatments. Over the six-year study, total maize yield in the RF + DI treatment was 5580 kg/ha more than in the CFI treatment and 6500 kg/ha more than in the DI treatment. Wheat yields in the RF + DI and SM + DI treatments were similar to the CFI treatment but slightly more than in the DI treatment. At harvest, there was no significant difference in water storage in the 0-200 cm soil profile among the RF + DI, SM + DI, DI, and CFI treatments. Nitrogen fertilizer application significantly increased maize and wheat yield compared to the unfertilized treatment; however, there was no further yield response when the N application rate exceeded 120 kg N/ha. In summary, these results indicated that DI in combination with SM or RF practices increased crop yield and WUE in the winter wheat-summer maize crop rotation. Compared to CFI practices, the SM + DI and RF + DI practices reduced the amount of irrigation water applied over a six-year period by about 350 mm.     

Pesticide discharge and water management in a paddy catchment in Japan

Concentrations of several pesticides were monitored in a paddy block and in the Kose river, which drains a paddy catchment in Fukuoka prefecture, Japan. Detailed water management in the block was also monitored to evaluate its effect on the pesticide contamination. The concentrations of applied pesticides in both block irrigation channel and drainage canal increased to tens of μg/L shortly after their applications. The increase in pesticide concentrations was well correlated with the open of irrigation and drainage gates in the pesticide-applied paddy plots only 1–3 days after pesticide application. High concentration of other pesticides, mainly herbicides, was also observed in the inflow irrigation and drainage waters, confirming the popularity of early irrigation and drainage after pesticide application in the area. The requirement of holding water after pesticide application (as a best management practice) issued by the authority was thus not properly followed. In a larger scale of the paddy catchment, the concentration of pesticides also increased significantly to several μg/L in the water of the Kose river shortly after the start of the pesticide application period either in downstream or mid–upstream areas, confirming the effect of current water management to the water quality. More extension and enforcement on water management should be done in order to control pesticide pollution from rice cultivation in Japan.     

SRI as a methodology for raising crop and water productivity: productive adaptations in rice agronomy and irrigation water management

The System of Rice Intensification (SRI), developed in Madagascar almost 30 years ago, modifies certain practices for managing plants, soil, water, and nutrients with the effect of raising the productivity of the land, labor, and capital devoted to rice production. Certain production inputs are reduced—seeds, inorganic fertilizer, water, and fuel where water is pumped—with increased yield as a result. This paper introduces the subject of SRI, which is then addressed variously in the articles that follow. SRI is gaining interest and application in over 40 countries around the world. Its practices make soil conditions more aerobic and promote greater root growth, as well as larger, more diverse communities of beneficial soil biota. These below-ground changes support more productive phenotypes above-ground for practically all rice genotypes (cultivars) tested so far, with supportive evidence accumulating both from scientific institutions and field applications. SRI methodology remains controversial in some circles, however, because of the transformational change it introductions into traditional lowland rice production systems. This issue of PAWE brings together the results of formal research on SRI in a number of countries (Part I) and also reports on initiatives by government agencies, NGOs, universities, or the private sector, bringing knowledge of SRI to farmers in a wide range of agroecological circumstances (Part II). This introduction presents the basic principles that underlie SRI and discusses the nature of this innovation as well as considers some of the issues in contention. SRI continues to evolve and expand, being a work in progress. Its concepts and methods are being extended also to upland (rainfed) rice production, as well to other crops. Accordingly, SRI should not be regarded or evaluated in conventional terms as if it were a typical component technology. It is understood more appropriately in terms of a paradigm shift for rice production. In particular, it calls into question the long-standing belief that rice is best produced under continuously flooded conditions.     

提高直播水稻田间出苗率的几项措施

分析了南疆稻区水稻直播由于受气候、土地质量、种子、肥料、水层管理、害虫等因素影响致使出苗率较低,同时提出了采取精细整地、选育良种、适期早播、加强肥水管理、防治病虫草害等技术措施提高出苗率.     

提高直播水稻田间出苗率的几项措施

分析了南疆稻区水稻直播由于受气候、土地质量、种子、肥料、水层管理、害虫等因素影响致使出苗率较低,同时提出了采取精细整地、选育良种、适期早播、加强肥水管理、防治病虫草害等技术措施提高出苗率。     

Crisis management of water shortage in an irrigation area with a pipeline network system

Problems caused by water shortage in a paddy-field district with a pipeline network system are different from those in a district with an open channel system. Abnormally low rainfall in Japan caused a very serious water shortage in 1994. A survey was carried out in the Hokuriku region, about 300 km in the north of Tokyo, and a typical paddy cultivation area, to determine problems in irrigation practices caused by water shortage and to find countermeasures for the problems. The following results were obtained. A tank model was proposed to estimate water requirements at the field level. The results showed that the amount of rainfall during the irrigation period in 1994 was only 27.1% of an average year and the rate of water sufficiency at the field level was 70.6%. Then, a simulation method was proposed to estimate hydraulic phenomena in a pipeline network system. The result showed that the pipeline network system distributed water to each hydrant unequally during water shortage. Based on simulations, the methods to equalize water supply to each hydrant and to set up reuse system of water were proposed.     

Sward structure management for a maximum short‐term intake rate in annual ryegrass

This study tested the hypothesis that different sward structures, which were constructed by varying the pre‐ and post‐grazing sward heights of annual ryegrass pasture (Lolium multiflorum Lam.) in southern Brazil, affect the short‐term intake rate (STIR) by dairy cows. Treatments consisted of four sward‐management strategies defined by a combination of two pre‐ (25 and 15 cm) and two post‐grazing sward heights (10 and 5 cm): 15‐05, 15‐10, 25‐05 and 25‐10. A completely randomized block design with four replicates was used for the experimental design. The STIR was determined by the double‐weighing technique. Jaw movements were evaluated using automatic recorders (IGER Behaviour Recorder). The results showed that treatment 25‐10 allowed the animals to collect more herbage with a greater bite mass and thus resulted in a greater STIR. Treatments in which sward height was reduced to 10 cm generally favoured the ingestion process than treatments with a post‐grazing sward height of 5 cm.     

Influence of overplanting paddy rice on irrigation water delivery performance: a case study in the Dakalt branch canal,Nile Delta of Egypt

In the North Nile Delta of Egypt, the impacts of overplanting paddy rice on water delivery performance have not been discussed quantitatively. Further, the amount of water that could have been saved if farmers would follow the planned area is unknown. In this study, water delivery performance was assessed by comparison of actual paddy rice planting and the government’s planned conditions. For both conditions, performance indicators relating to adequacy, equity, and dependability were analyzed across six locations in conjunction with the branch canal water level in 2013 and 2014. Based on the difference between the actual water supply and planned water demand, the amount of water that could have been saved for downstream uses was calculated. The average adequacy for the investigation period was good at one location, fair at 2 locations, and poor at 3 locations in both years. Further, adequacy under both actual and planned conditions was poor in late July at all locations. The planned adequacy and dependability downstream and equity among locations improved compared to the actual condition in both years. Under the condition that paddy rice area is the upper limit planned by the government, about 12.3% and 9.6% of water could be potentially saved in each year. The difference between actual and planned water delivery performance is caused by the branch canal’s low water level. Control of overplanting paddy rice and coordination of water distribution among water user associations would improve stable water level in the canal and, eventually, water delivery performance.

     

Influence of airflow rate on chip potato storage management

Through-the-pile ventilation is a common practice for potatoes stored in bulk. Research was initiated in 1986 to study the influence of ventilation rate on the temperature, moisture and market quality of bulk stored chip potatoes. Ventilation rates up to 168 m³ hr^?1 t^?1 were used. All ventilation rates achieved the required temperature and humidity control. Fan operation time (hours) was not reduced proportional to the increased ventilation rate. The higher ariflow resulted in proportionally less time being spent to correct pile temperature differentials. The Atlantic variety potatoes were utilized for potato chip production in all three seasons studied. Market quality after storage, measured by tuber sugar content, chip color and chip defects, was similar for all ventilation rates. For the last two storage seasons studies, the potatoes were marketed from the storage research bins at high levels of quality following 115 to 142 days of storage. Average weight losses for the airflow rates used were not statistically different. However, potato weight loss uniformity was proportional to increased ventilation rates.     

Studies on a novel polyacrylonitrile copolymer/cellulose acetate blending water absorbency fiber

Polyacrylonitrile copolymer (CPAN) was obtained by water-deposit polymerization, using acrylonitrile (AN), vinyl acetate (VAc), potential crosslinking moiety (hydropropyl acrylate, HQ) as monomer, NaClO₃ as initiator. CPAN was blended with cellulose acetate (CA) to prepare CPAN/CA blending fiber via wet spinning. The fiber was post-crosslinked and hydrolyzed to get water absorbency fiber. The structures and properties of the fibers were studied and the results showed that potential crosslinking moiety was necessary in making CPAN/CA blending water absorbency fiber. The saponification reaction was accelerated after blended with CA and the interfacial microvoids enhanced the water absorbency ability.     

The development and management policy of water resources in Taiwan

Taiwan is a small island located in monsoon Asia with an annual precipitation exceeding 2,500 mm, which is 2.6 times the world average. However, water available for each person in Taiwan is less than one seventh of the world average due to Taiwan's crowded population and river basin characteristics. Steep land slope and uneven time and space distribution of rainfall have caused water resources problems. Providing a pure and plentiful supply of water for the people challenges the Water Resources Agency in Taiwan. History is a powerful tool for portraying the future. This paper discusses major themes in the review of water resources development over the last centuries. The changes in social-economic development, water resources infrastructure and demands of water are central to the discussion, with an eye to the plentiful and sustainable implications of water resources management in Taiwan. The water policy in the twenty-first century is also outlined.Dr. Hwang is the Advice of the Council for Economic Planning and Development (CEPD), Ministry of Economic Affairs (MOEA), Taiwan, Chairman of the Water Resources Committee, Chinese Institute of Civil and Hydraulic Engineering, a board member of the International Commission on Irrigation and Drainage (ICID) Chinese Taipei Committee, former chairman of the Chinese Society of Agriculture Engineering (CSAE), former director of Water Resources Agency (WRA), former director of the Taiwan Provincial Water Conservancy Agency (TPWCA), and former director of the Taiwan Provincial Water Conservancy Bureau (TPWCB).     

The effects of water management,timing and the rate of several herbicides on the growth of Murdannia keisak (Hassk.) Handel-Mazz

Murdannia keisak is a competitive rice weed found throughout the world. The aims of this study were to investigate the influence of different water managements on the growth of M. keisak under greenhouse conditions, and to assess the efficacy of common rice herbicides against it under field conditions.Three water management techniques were tested under greenhouse conditions: saturation, intermittent irrigation, and continuous flooding. The efficacy against M. keisak was evaluated in paddy fields during 2003–2005. In 2003, bispyribac-sodium was applied alone or in combination with triclopyr or metosulam at 20, 27, and 32 days after seeding (DAS). In 2004 and 2005, bispyribac-sodium was applied once (30 DAS), but at two application rates.Results for the three water treatments showed continuous flooding reduced M. keisak biomass most as confirmed by aboveground fresh weights. In the paddy field experiments, bispyribac-sodium also proved highly effective against M. keisak and was selective to rice with more than 90% efficacy. The addition of tryclopyr or metosulam to bispyribac-sodium failed to improve its herbicidal efficacy. Finally, the best M. keisak control at field condition was obtained with continuous flooding combined with bispyribac-sodium.     

Cis- and trans-protopinium,a novel nematicide,for the eco-friendly management of root-knot nematodes

Plant-derived nematicides are being increasingly used while select synthetic nematicides are phased out for environmental concerns. This is the first report on the in vitro nematicidal activity of cis- and trans-protopinium isolated from roots of Fumaria parviflora and its in vivo effect on the southern root-knot nematode Meloidogyne incognita. Cis- and trans-protopinium was isolated from the methanolic fraction FM2.1, and its structure elucidated using ¹³C and ¹H nuclear magnetic resonance (NMR). The NMR spectra were characterized using deuterated dimethyl sulfoxide (DMSO) at temperatures of 25 and 80 °C. In an in vitro study, over 120 h of incubation, the area under cumulative percent hatch inhibition and mortality of cis- and trans-protopinium reached 100% at a concentration of 200 μg mL⁻¹. In the greenhouse and field settings, cis- and trans-protopinium was evaluated against M. incognita on tomato at a concentration of 100, 200, and 300 μg mL⁻¹ for two consecutive seasons, that is, spring and autumn, in 2010. At a concentration of 300 μg mL⁻¹ in the greenhouse and field trials during spring and autumn, cis- and trans-protopinium significantly reduced the nematode galling index, the number of females per gram of root, and the reproduction factor, as well as increased plant height, fresh and dry shoot weights, and root length. Therefore, cis- and trans-protopinium can be used as an effective and safe nematicide against M. incognita on tomato in an organic and sustainable agricultural production system. Phytochemicals have various agricultural applications, especially to control economically important nematode pests.     

Sophorolipids: a source for novel compounds

Renewable resources, such as rapeseed oil or oleic acid, combined with glucose were used both in a feed-batch and two-stage continuous process for the production of sophorolipids with the yeast Candida bombicola ATCC 22214. High yields >300 g l⁻¹ and increased productivities of 57 g l⁻¹ d⁻¹ (feed-batch) and 76 g l⁻¹ d⁻¹ (continuous mode), respectively, were obtained by using optimized cultivation conditions. The key-factors for enhanced sophorolipid production are presented. The acidic sophorolipid was used for further modification after alkaline hydrolysis and purification. A novel glucoselipid was synthesized by using the enzyme naringinase (EC 3.2.1.40). A (ω-1)-hydroxyfatty acid, commercially not yet available and difficult to prepare by organic synthesis, was released by acidic hydrolysis, purified and is proposed as a precursor for plastics and flavours.     

Self-made microlysimeters to measure soil evaporation: a test on aerobic rice in northern Italy

Soil water balance researches aimed at improving crop water use efficiency often require the determination of soil evaporation. In this technical note, the performance of simple and cheap self-made microlysimeters for the measurement of soil evaporation was tested in an aerobic rice field managed by intermittent irrigation. Six microlysimeters obtained by cutting commercial PVC pipes and closing the bottom ends with caps were positioned in appropriate PVC outer casings installed into the soil. Three measurement campaigns (for a total of 11 measurement periods) were carried out in different vegetation cover conditions (rice development, rice maturity and after the crop harvest). Evaporation amounts were analysed with respect to climatic data, vegetation cover and soil water status and, finally, compared with the simulated results of a FAO Penman–Monteith “dual crop coefficient” model implemented with site-specific data. Evaporation rates in the three campaigns were closely dependent on the evaporative demand of the atmosphere ETo (R ² = 0.96, 0.98, 0.96), while the slope of the linear regression curve was strongly related to the vegetation cover (b = 0.29, 0.12, 0.94); soil water content, always rather high during the experiments, did not affect the evaporation rate. Measured and simulated evaporation amounts showed a close agreement: the linear regression was characterized by slope and R ² of 0.98 and 0.95, while RMSE and NSE indices were 0.15 and 0.94. From the tests conducted, we can conclude that the self-made microlysimeters presented in this note are affordable instruments for measuring soil evaporation, at least in temperate climate conditions.     

Yield response,water productivity,and seasonal water production functions for maize under deficit irrigation water management in southern Taiwan

As the challenges toward increasing water for irrigation become more prevalent, knowledge of crop yield response to water can facilitate the development of irrigation strategies for improving agricultural productivity. Experiments were conducted to quantify maize yield response to soil moisture deficits, and assess the effects of deficit irrigation (DI) on water productivity (water and irrigation water use efficiency, WUE and IWUE). Five irrigation treatments were investigated: a full irrigation (I₁) with a water application of 60 mm and four deficit treatments with application depths of 50 (I₂), 40 (I₃), 30 (I₄), and 20 mm (I₅). On average, the highest grain yield observed was 1008.41 g m^?2 in I₁, and water deficits resulted in significant (p < .05) reduction within range of 6 and 33%. This reduction was significantly correlated with a decline in grain number per ear, 1000-grain weight, ear number per plant, and number of grain per row. The highest correlation was found between grain yield and grain number per ear. The WUE and IWUE were within range of 1.52–2.25 kg m^?3 and 1.64–4.53 kg m^?3, respectively. High water productivity without significant reduction in yield (<13%) for I₂ and I₃ compared to the yield in I₁ indicates that these water depths are viable practices to promote sustainable water development. Also, for assessing the benefits of irrigation practices in the region crop water production functions were established. Maize yield response to water stress was estimated as .92, suggesting the environmental conditions are conducive for implementing DI strategies.     

Evaluation of water intake rate using the diffusive tank model in the low-lying paddy area

The subject of this study is water management in low-lying paddy fields. The objective of this study is to quantify the water requirement, and estimate an appropriate volume and facilitate management of irrigation water in areas where it is difficult to estimate the flow rate continuously. A field observation was conducted at a 14-ha study site located in the Kuwabara area, Fukuoka City, southwest of Japan, to evaluate water management conditions in the command area of the reservoir. This site near the reservoir was selected, because it was impossible to understand the water supply situation in the entire command area. The farmers in this region have been unable to retain sufficient irrigation water. The observation results indicate that the water depth fluctuates widely in every irrigation canal. The canals are frequently empty because rotational irrigation is conducted by water managers; this makes quantifying the flow rate in the irrigation canal very difficult. To quantify the water requirement, an improved tank model was introduced. The accuracy of the model was examined by comparing the observed and calculated ponding depths at a paddy field. The simulation results agreed with the observed data. Using this model, water management for the reduction of water managers’ labor was simulated. Simulation results indicated that rotational irrigation effectively reduces labor and saves irrigation water.     

Participatory system for water management in the Toyogawa Irrigation Project, Japan

In principle, participatory irrigation management (PIM) means the involvement of irrigation users in all aspects at all levels of irrigation management. In practice, all over the world efforts are being made to realize the principles. However, in the execution of PIM, role sharing between farmers and government is a serious problem, and thus a clear method and ideas are needed to improve PIM. In particular, a broad discussion of role sharing is demanded. This article illustrates how the Japanese way of role sharing in PIM is realized based on the case of the Toyogawa Irrigation Project. Organizationally, the project is jointly managed by five entities, including both the public sector and the farmers’ organizations. These entities have clearly divided their functional roles, with the ultimate decision power in all aspects of irrigation management given to organized farmers. The power is realized either directly or through the land improvement districts’ representative system depending on the levels of the irrigation system. The public entity provides coordination support to create a transparent forum of discussion together with scientific information for farmers’ understanding and decision making. The participatory institutional line-up of this project enables the upland areas that suffered periodically from water deficits.     

Macropore structure and water management affect greenhouse gas emissions in agricultural fields

Paddy and Water Environment - The process of greenhouse gas (GHG) emission processes is substantially affected by soil factors. Here, an intensive experiment was conducted to observe the effects of...