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Tillage practices which improve water availability and water use efficiency ( WUE ) are beneficial for rain-fed agriculture. However, there is little consensus about the effects of ridge tillage and mulching, combined with different rainfall and N fertilization conditions, on water status and productivity in winter wheat fields. The current study aimed to investigate the effects of ridge tillage and mulching on water availability, grain yield, and WUE in rain-fed winter wheat under different rainfall and N conditions. A three-year field experiment was conducted during 2011–2014 following a split-split plot design. The experiment included two humid growing seasons (2011–2012 and 2013–2014) and one dry growing season (2012–2013). Nitrogen application rates were 0 and 180 kg N ha –1 . Tillage systems included conventional tillage (CT, as control), stalk mulching (SM), film mulching (FM), ridge tillage without mulch (RT), ridge tillage with film on ridges (RTf), and ridge tillage with film on ridges and stalk in furrows (RTfs). Results showed that averaged across growing seasons and N treatments, ridge tillage and mulching decreased evapotranspiration by 8.3%–16.2%, and increased grain yield and WUE by 4.2%–15.2% and 16.7%–36.8% compared with CT, respectively. Ridge tillage and mulching tended to increase grain yield especially when rainfall was deficient, and tended to increase WUE especially when N supply was deficient. Spike number per hectare and grain number per spike made significant contributions to grain yield when all three yield components were considered. Ridge tillage and mulching tended to increase mass-based and area-based canopy moisture during regreening (stage 6 in Feekes scale, late Feb–early Mar) to grain-filling stage (middle May) which was positively correlated with grain yield. Lower leaf area index ( LAI ) in ridge tillage and mulching treatments led to grain yield loss, but the loss was alleviated by greater total chlorophyll in flag leaves. Overall, ridge tillage and mulching improved water availability, grain yield, and WUE in rain-fed winter wheat, especially when N and rainfall were deficient. [ABSTRACT FROM AUTHOR]

Abstract: Efficiency of fertilizer N is becoming increasingly important in modern agricultural production owing to increasing food requirement and growing concern about environments. However, there is almost no study regarding its long-term efficiency in wheat and maize cropping systems. Long-term (15 years) experiments involving wheat (Triticum aestivum L.) and maize (Zea mays L.) rotations at five field sites with various soil and climate characteristics in China were used to determine the nitrogen (N) efficiency, including the physiological efficiency, recovery efficiency and N mass balance of soil–plant systems in response to different fertilization treatments. The present study consisted of nine treatments: unfertilized, N, phosphorus, potassium, straw and manure or their combinations. The contribution of N fertilizers to wheat yield was higher than to maize and suggested that wheat could be given priority over maize when determining N application rates. Uptake of 1kg N produced 35.6kg of wheat grain and 39.5kg of maize grain. The deficit of N in soils without applied N ranged from 40 to 103kgNha−1 year−1, while N surpluses in soils with applied N fertilizers ranged from 35 to 350kgNha−1 year−1. The apparent accumulated N recovery efficiency (NREac) varied widely from 4% to 90%: unbalanced fertilization and other soil limiting factors (such as aluminium toxicity) were associated with low NREac. In the treatments of combination of N, phosphorus and potassium with normal application rates, the average of NREac in four out of five sites reached 80%, which suggested that best management of N fertilizers could recover most of N fertilizers applied to soils. The results will be helpful to understand the long-term fate of N fertilizers and to optimize the N fertilization for agricultural practices and environment protection. [Copyright &y& Elsevier]

Abstract: Spot blotch, caused by Cochliobolus sativus, is a serious disease of wheat (Triticum aestivum L.) in the warm lowlands of South Asia. A field study was conducted using two wheat varieties (Bhrikuti and Sonalika) during the 2001 and 2002 wheat seasons in Rampur, Nepal, to determine the effect of nitrogen, phosphorus, potassium, and chlorine fertilization on reducing spot blotch severity in wheat, and its associated increase in grain yield. Application of N alone reduced spot blotch severity by 8% in 2002. Phosphorus fertilization had no effect on spot blotch development. The balanced application of N, P, and K reduced disease severity by 15 and 22% in 2001 and 2002, respectively. Application of KCl as well as CaCl2 reduced spot blotch severity, but the former caused 11% greater reduction than the latter. The two varieties responded differently to the mineral nutrients’ effect on spot blotch severity, suggesting the nutrients’ importance in cultivar selection when considering the effect of soil fertility on susceptibility to foliar diseases. The lower disease severity and higher grain yield observed after the application of KCl compared to CaCl2 showed that KCl should be used on K-deficient soils in the warmer wheat growing regions of South Asia where spot blotch is a serious perennial wheat disease in intensive rice–wheat cropping systems. [Copyright &y& Elsevier]

Abstract: In organic wheat, nitrogen is one of the key limiting factors responsible for irregular productivity and low quality. On arable farms, the decreasing use of N-organic sources such as forage legumes, manures and composts relative to mixed-farms requires the development of suitable fertility strategies based on the use of off-farm organic fertilizers. The Azodyn crop model was previously adapted to organic fertilization and evaluated on various field trials in order to predict grain yield, grain protein content and soil mineral N at harvest. This paper analyses the value of Azodyn-Org as a decision-tool for managing N fertilization by (1) evaluating the economic benefits of an organic N application and (2) selecting optimal fertilization strategies according to farmers’ constraints and conditions. It appears that Azodyn-Org is relevant for selecting appropriate strategies in various conditions only if the multiple limiting factors (e.g. weeds, diseases, soil compaction) effect on yield was well predicted. In these conditions, its use could allow to identify the fields where an organic N application is profitable, through rule-based simulations. The development of an early risk-assessment method to predict the effect of major limiting factors is required before providing this tool to users. Other methodological elements of model-based explorations are addressed in the discussion. [Copyright &y& Elsevier]

China is the most populous nation and largest food producer and consumer in the world. In terms of planted area and output, wheat (Triticum aestivum L.) (including both winter and spring habit wheat) is the number one crop in northern China, and currently almost all irrigated wheat is conventionally planted in narrow spaced rows on the flat and is irrigated by flood irrigation within bordered basins. Conventional flat planting for winter wheat has some disadvantages. The use of flood irrigation can result in a low potential irrigation water use efficiency and inefficient use of nitrogen. It can also cause crusting of the soil surface following irrigation and can contribute to the degradation of some soil properties. In addition, it can result in higher levels of crop lodging. A raised bed-planting system with a number of defined rows (usually two to four rows) planted on top of the bed with furrow irrigation was found to overcome these disadvantages. The benefits of the raised bed-planting system with furrow irrigation compared with conventional flat planting with flood irrigation were found as follows: first, there was a savings in some years of as much as 30% of applied irrigation water combined with enhanced water use efficiency by changing from flood to furrow irrigation; second, the crust problem on the soil surface was eliminated and soil physical status was greatly improved; third, nitrogen use efficiency could be improved by 10% or more because of improved nitrogen placement possibilities; fourth, the microclimate within the field was changed due to the orientation of the wheat plants in rows on the beds with the bed-planting system, which reduced crop lodging and decreased the incidence of some wheat diseases. These advantages, interacting together, were found to improve grain quality and increase grain yield by more than 10%. [Copyright &y& Elsevier]