Effect of Time and Rate of Application of Nitrogen on The Yield of the Mexican Wheat under the Semi-arid Conditions of Tunisia

AbstractHigher fertilization on winter wheat increased the fluctuation of winter wheat yield in different rainfall years and impacted the sustainable development of winter wheat production on the Loess Plateau. Based on the long term field experimental data at Chagnwu Agricultural Station, this paper evaluated the EPIC model. And this paper also suggested a sustainable fertilizer level for winter wheat, based on the analysis of simulation results in different rainfall regions. Results of this study indicated that: 1) The EPIC model simulated both winter wheat yields and soil water among different fertilizer levels well, with the mean R value of 0.91 and 0.89 respectively. 2) With the increasing of fertilizer, the value of IRFG (Increase Rate of Grain yield by Fertilizer) and WUEG (Water Using Rfficiency for Grain yield) became higher, when soil water in deep soil was not be used excessively; however, the value of IRFG became lower, when soil water in deep soil was used excessively. 3) In the semi-humid region, fertilizer for winter wheat should be from N4 to N5; in the semi-humid and drought-prone region and in the semi-arid region, it should be from N3 to N4; in the semi-arid and drought-prone region, it should be lower than N3.KeywordsThe loess plateauWinter wheatFertilizerEPIC model

A study of the continuous cropping of spring wheat was conducted in the semi-arid area of northern Kazakhstan, on black soils with an annual precipitation of 350 mm. Different cultural practices were tested: simple, common and intensive. Under the three practices, grain yields from a second wheat crop after summer fallow were 62.5, 81.7 and 84.6% respectively, compared to the first crop after summer fallow. Under continuous cropping, yields were 50.0, 67.7 and 82.9%, respectively, compared to the first crop after summer fallow.

Abstract In China, wheat is second to rice among the food grains. In the 1970's seasonal multiple cropping was implemented in some areas. The growing of winter wheat further north resulted in extensive freeze injury while wheat planted in other areas, deficient in water supply, resulted in low and highly variable annual production. The geographic areas for growing winter wheat vs. spring wheat in China are set out. These suitable wheat-growing areas are based on climatic resources that include seasonal temperature and water balance considerations. The climatic potential for growing wheat in many areas of northern and western China is based on an analysis of seasonal temperature and crop-water sufficiency during the principal growing stages that influence grain yields. Potential wheat yields are discussed, including the climatic potential for crop yields vs. actual yields under rain-fed cropping practices.

It is difficult to establish agronomic practices for wheat (Triticum aestivum L.) production in Mediterranean regions because of high annual variability in rainfall. Plant density is a factor of particular importance in wheat production systems because it can be controlled. This study was conducted to determine the optimum seeding rates of Mediterranean types of wheat in irrigated Mediterranean systems. Field experiments were conducted under irrigation at two locations of the Ebro Valley, Spain, during two growing seasons, 1999–2000 and 2000–2001. Six seeding rates were compared: 150, 175, 250, 300, 400, and 500 seeds m−2 with four adapted wheat varieties including a hybrid wheat. Seeding rate affected grain yield and yield components in three of the four environments, but its effect varied with the environment. The plant densities giving the highest yields were at least 400 to 500 plants m−2 for most of the varieties studied. The results suggest that the rate of seeding under irrigation for Mediterranean areas might be higher than those used in other wheat-growing areas.

Efficient use of rainwater is essential for producing sufficient food crops in semi-arid regions in southern Africa. If rainwater is harvested and channelled to an arable land in a dry area, risk for crop production with variable rainfall due to the El Niño-Southern Oscillation (ENSO) phenomena, can be reduced. Crop modelling is a powerful tool to understand processes of plant growth and development under particular environmental conditions. A crop simulation study was, therefore, carried out to demonstrate El Niño/La Niña effects on maize ( Zea mays ) yield with a micro-catchment water harvesting (WH) production system in a semi-arid region (Bloemfontein, South Africa). A weather-crop growth model combined with rainfall intensity and runoff models was used to estimate maize yield in the WH production system. The simulation study confirmed that the productivity is greater in La Niña than El Niño tendency years, and under El Niño conditions the highest risk of low yield of maize grown with the WH technique occurs if the crop is planted at higher densities (e.g. 18,000 plants/ha) earlier in the summer growing season (e.g. the first day of November) with a profile empty of soil water at planting.

A spring wheat growth model (SUCROS-87) was used to identify moisture stress periods during the growing seasons and simulate yield potentials of durum wheat (Triticum turgidum var. durum) in six durum wheat growing regions of Ethiopia. The start of the rainy season and distribution of rainfall were erratic, particularly in the low-altitude regions. As a result, simulated dates of emergence varied from June to August. Moisture stresses of various intensities, at different growth stages of the plant, were limiting to durum wheat production in all the regions except Debre Markos. Terminal moisture stress was simulated in 7 out of 10 years in all locations except Debre Markos, whereas intermittent stress. was simulated in three locations in 2 out of 10 years. In Metahara rain-fed durum wheat production is not feasible without irrigation. Water use efficiency decreased with decreasing rainfall but the transpiration coefficient increased. The average simulated potential grain yields at all the locations were high (6600 kg ha−1) compared with the actual national average. Development of versatile and region-specific improvement strategies are emphasized to improve durum wheat production in the country.

Based on the daily data of 65 meteorological stations from 1961 to 2010 and the crop phenology data in the potential cultivation zones of thermophilic and chimonophilous crops in Northeast China, the crop potential yields were calculated through step-by-step correction method. The spatio-temporal distribution of the crop potential yields at different levels was analyzed. And then we quantified the limitations of temperature and precipitation on the crop potential yields and compared the differences in the climatic resource utilization efficiency. The results showed that the thermal potential yields of six crops (including maize, rice, spring wheat, sorghum, millet and soybean) during the period 1961-2010 deceased from west to east. The climatic potential yields of the five crops (spring wheat not included) were higher in the south than in the north. The potential yield loss rate due to temperature limitations of the six crops presented a spatial distribution pattern and was higher in the east than in the west. Among the six main crops, the yield potential loss rate due to temperature limitation of the soybean was the highest (51%), and those of the other crops fluctuated within the range of 33%-41%. The potential yield loss rate due to water limitation had an obvious regional difference, and was high in Songnen Plain and Changbai Mountains. The potential yield loss rate of spring wheat was the highest (50%), and those of the other four rainfed crops fluctuated within the range of 8%-10%. The solar energy utilization efficiency of the six main crops ranged from 0.9% to 2.7%, in the order of maize> sorghum>rice>millet>spring wheat>soybean. The precipitation utilization efficiency of the maize, sorghum, spring wheat, millet and soybean under rainfed conditions ranged from 8 to 35 kg . hm-2 . mm-1, in the order of maize>sorghum>spring wheat>millet>soybean. In those areas with lower efficiency of solar energy utilization and precipitation utilization, such as Changbai Mountains and the south of Lesser Khingan Mountains, measures could be taken to increase the efficiency of resource utilization such as rational close-planting, selection of droughtresistant varieties, proper and timely fertilization, farming for soil water storage, optimization of crop layout and so on.

In 2009,114 high production wheat samples were selected from four provinces in China at arid or half arid latitude,such as Hebei,Shandong,Shanxi,Shanxi.The grain sense organ character,the qualitative index,the quality character were analyzed.The result indicated that 15.8% samplesachieve the high quality strong muscle wheat national standards,0.9% samples achieves the high qualityweak gluten wheat national standards.With the experiment,the different suitable varieties may be analyzed to achieve the saving water,high grain output and quality.

Alfaking,Pick 3006,Pick 8925 and Spreador-3 were introduced from America and Canada,using Zhonglan No.1 as the regional control After completed district tests in the arid and semi-arid areas in 2002-2004,adaptability evaluation were conducted in the semi-humid area in 2008 and 2009.The result indicated that,five introduced alfalfa could grow normally in the semi-humid area and completed all the procreation periodicity,without exceptional representation and diseases and pests.We analyzed procreation periodicity,nutrition component,growth rapidity and ratio of stem and leaf.It also shown that the highest content of dissociative proline and soluble sugar was Alfaking,the lowest content of malondialdehyde also was Alfaking and the fresh yield of Alfaking was 125 642.8 kg/hm2 in the semi-aridity areas.Spreador-3nd Zhonglan No.1 were the choiceness varieties.The study advised that those five alfalfas can cultivate in the semi-arid and semi-humid areas in Loess plateau.

In this study we are examining the climate change impacts on cereal yields in the North-West of Tunisia by focusing on the effect of increase in temperature on durum wheat yields. The index of growing degree days (GDDs) or the corresponding growing season length (GSL) is commonly used in agronomic studies to determine the effect of temperature on yields. The main goal of the current study is to analyse the effect of historical increase of temperature on GSL of durum wheat in North-West of Tunisia (Beja and El-Kef) and assess the future impact of climate change on wheat yields. We find that high temperatures correspond to a decrease in growing season length. Future increases in temperatures between 1.5 and 3.5°C may reduce the yield of wheat in the Beja district between 16% and 19%.

Sorghum has become ever more prominent on the global energy scene, with studies in the area becoming extremely important. Agricultural production in the semi-arid region of the Brazilian Northeast is intrinsically dependent on rainfall in the region. However, on both inter- and intra-annual scales, the rainfall regime is quite irregular. The aim of this study was to evaluate the productivity of sorghum grown under a rainfed regime, and the water-use efficiency of crops in the semi-arid region of the northeast of Brazil. The work was carried out in the city of Tabuleiro do Norte in the semi-arid region of the State of Ceara. Mean productivity of the sorghum was 919.42 kg·ha-1, with maximum values being recorded for lot 02 (1032 kg·ha-1), lot 03 (1102 kg·ha-1), lot 04 (2143 kg·ha-1) and lot 12 (1367 kg·ha-1). The greatest value for water-use efficiency, 1.13 m3·kg-1, was found for lot 04, while the smallest value, 4.83 m3·kg-1 was seen in lot 02. It was found that the low productivity of sorghum in a rainfed regime shows that the lack of success in production systems in semi-arid regions is not due to the total amount of rainfall, but rather the spatial and temporal distribution of the rains, as well as the occurrence of hot, dry spells. Furthermore, it can be seen that the best ratio of grain production to water demand shows a strong correlation with the distribution of water throughout the cycle, and not only with the total volume.

It is very important to determine the irrigation water requirement (IR) of crops for optimal irrigation scheduling under the changing climate. This study aimed to investigate the impact of climate change on the future IR and yield of three strategic crops (winter wheat, barley, fodder maize) in the semi-arid Qazvin Plateau, Iran, for the periods 2016–2040, 2041–2065, and 2066–2090. The Canadian Earth System Model (CanESM2), applying IPCC scenarios rcp2.6, rcp4.5, and rcp8.5, was used to project the monthly maximum and minimum temperatures and monthly precipitation of the region. The results indicated that the maximum and minimum temperatures will increase by 1.7 °C and 1.2 °C, respectively, under scenario rcp8.5 in the period 2066–2090. The precipitation will decrease (1%–13%) under all scenarios in all months of the future periods, except in August, September, and October. The IR of winter wheat and barley will increase by 38%–79% under scenarios rcp2.6 and rcp8.5 in the future periods. The increase in the IR of fodder maize will be very slight (0.7%–4.1%). The yield of winter wheat and barley will decrease by ~50%–100% under scenarios rcp2.6 and rcp8.5 in the future periods. The reduction in the yield of maize will be ~4%. Serious attention has to be paid to the water resources management of the region. The use of drought-tolerant cultivars in the region can be a good strategy to deal with the predicted future climatic conditions.

Sesame is one of the main oil crops grown under dryland areas in Sennar state, Sudan. However, rainfall is quite irregular within the season and between the seasons. Understanding the effect of rainfall variability on water requirement and yield of sesame is essential to help in selecting optimum management practices for crop production. The objective of this study was to determine the water requirement and water productivity of sesame crop grown under two agro-ecological zones and three farming systems. An experiment was conducted in two agroecological zones in Sennar State (semi-arid zone and semi-humid zone) during seasons 2014/2015 and 2015/2016.The tested cropping systems were conventional farming (CF), conservation agriculture (CA) and water harvesting techniques (WH). The collected data included weather data and sesame yield data. The results showed that the average values of reference evapotranspiration (ETO) during the two seasons ranged from 3.29 to 4.4 mm/day in semi-arid site and from 3.75 to 3.95 mm/day in semi-humid site. Regardless of agro-ecological site and season, the average values of crop factor (Kc) during the initial, development, midseason and late-season stages were 0.30, 0.75, 0.98 and 0.51, respectively. The average values of water requirement for sesame during initial, development, mid-season and late-season stages were 24.1, 87.8, 132.1 and 36.3 mm; and 20.1, 78.2, 114.5 and 37.9 mm, in semi-arid and semihumid sites, respectively. The average water requirement was 2802 and   2516 m3/ha in semi-arid and semi-humid sites, respectively. The overall average values of water productivity for sesame crop in semi-arid site was 0.18 kg/m3 and it was 0.29 kg/m3 in semi-humid site. Water harvesting and conservation agriculture systems gave higher performance compared with the conventional farming system for sesame production in dryland areas of Sennar state

For sustainable agriculture, efficient use of energy is of utmost importance. This study was conducted for a period of 3 years in Central Anatolia region of Turkey to find out how the energy balanc...

In recent years, evidence of recent climate change has been identified in South America, affecting agricultural production negatively. In response to this, our study employs a crop modelling approach to estimate the effects of recent climate change on maize yield in four provinces of Ecuador. One of them belongs to a semi-arid area. The trend analysis of maximum temperature, minimum temperature, precipitation, wind speed, and solar radiation was done for 36 years (from 1984 to 2019) using the Mann–Kendall test. Furthermore, we simulated (using the LINTUL5 model) the counterfactual maize yield under current crop management in the same time-span. During the crop growing period, results show an increasing trend in the temperature in all the four studied provinces. Los Rios and Manabi showed a decreasing trend in radiation, whereas the semi-arid Loja depicted a decreasing precipitation trend. Regarding the effects of climate change on maize yield, the semi-arid province Loja showed a more significant negative impact, followed by Manabi. The yield losses were roughly 40 kg ha−1 and 10 kg ha−1 per year, respectively, when 250 kg N ha−1 is applied. The simulation results showed no effect in Guayas and Los Rios. The length of the crop growing period was significantly different in the period before and after 2002 in all provinces. In conclusion, the recent climate change impact on maize yield differs spatially and is more significant in the semi-arid regions.

Rising temperature from climate change is the most threatening factor worldwide for crop production. Sustainable wheat production is a challenge due to climate change and variability, which is ultimately a serious threat to food security in Pakistan. A series of field experiments were conducted during seasons 2013–2014 and 2014–2015 in the semi-arid (Faisalabad) and arid (Layyah) regions of Punjab-Pakistan. Three spring wheat genotypes were evaluated under eleven sowing dates from 16 October to 16 March, with an interval of 14–16 days in the two regions. Data for the model calibration and evaluation were collected from field experiments following the standard procedures and protocols. The grain yield under future climate scenarios was simulated by using a well-calibrated CERES-wheat model included in DSSAT v4.7. Future (2051–2100) and baseline (1980–2015) climatic data were simulated using 29 global circulation models (GCMs) under representative concentration pathway (RCP) 8.5. These GCMs were distributed among five quadrants of climatic conditions (Hot/Wet, Hot/Dry, Cool/Dry, Cool/Wet, and Middle) by a stretched distribution approach based on temperature and rainfall change. A maximum of ten GCMs predicted the chances of Middle climatic conditions during the second half of the century (2051–2100). The average temperature during the wheat season in a semi-arid region and arid region would increase by 3.52 °C and 3.84 °C, respectively, under Middle climatic conditions using the RCP 8.5 scenario during the second half-century. The simulated grain yield was reduced by 23.5% in the semi-arid region and 35.45% in the arid region under Middle climatic conditions (scenario). Mean seasonal temperature (MST) of sowing dates ranged from 16 to 27.3 °C, while the mean temperature from the heading to maturity (MTHM) stage was varying between 12.9 to 30.4 °C. Coefficients of determination (R2) between wheat morphology parameters and temperature were highly significant, with a range of 0.84–0.96. Impacts of temperature on wheat sown on 15 March were found to be as severe as to exterminate the crop before heading. The spikes and spikelets were not formed under a mean seasonal temperature higher than 25.5 °C. In a nutshell, elevated temperature (3–4 °C) till the end-century can reduce grain yield by about 30% in semi-arid and arid regions of Pakistan. These findings are crucial for growers and especially for policymakers to decide on sustainable wheat production for food security in the region.

The ET of some crops In three semi-arid and one dry sub-humid climatic locations of Maharashtra were obtained from climatic parameter~ using the guidelines suggested by Doorenbos and Pruitt {1977). The values were 483-541 mm for kharif rice, 278-373 mm for wheat and 373-447 mm for kharif jowar. When compared, the estimated values with lysimetric observation, the values were in close agreement for rice, lower for wheat and again higher for kharif jowar. A wide variation in crop evapotranspiration was observed from semi-arid to dry sub-humid climates.