Irrigated Production Systems Research Articles

Assessment of Agricultural Land Suitability for Surface Irrigation Using Geospatial Techniques in the Lower Omo Gibe Basin, Ethiopia

Land suitability assessment for irrigation is critical to inform as well as manage current and future irrigated agriculture production systems. Land suitability analysis determines whether a given land area could potentially be used for specific crop production. The objective of this study was to identify the availability of suitable land for surface irrigation systems for the production of millet, sorghum, sugarcane, and wheat production in the Lower Omo Gibe plain, Southern Ethiopia. Land suitability analysis was performed by a parametric method using factors such as soil texture, effective soil depth, Calcium Carbonate (CaCO3), soil electrical conductivity (ECe), drainage class, and slope. Five land suitability classes were identified that include highly suitable (S1), moderately suitable (S2), marginally suitable (S3), currently not suitable (N1), and permanently not suitable (N2). Results showed that 6.6, 7.5, 6.6, and 6.6% of the study area mostly located in the western part of the basin, were highly suitable (S1) for irrigated millets, sorghum, sugarcane, and wheat crops production, respectively. However, the mountainous areas in the central part of the basin were classified as N2 due to the steep slope and shallow soil depth. Overall, the results of the study revealed that the use of various suitability analysis techniques could assist in identifying suitable land for irrigated agriculture.

Sustainability of agroecosystems by indices: A comparative study between indicators of ecological footprint sustainability and emergy analysis; a case study in Dez catchment, Iran

Efficient farm management is one of the most important issues in achieving Sustainable performance. Ecological Footprint (EF) measurement and Emergy Analysis (EA) are appropriate tools to achieve the principles of sustainability in different ecosystems. This study aimed to compare the indicators and determine the ecological sustainability of two cropping systems of irrigated wheat and grain maize using ecological footprint evaluation and emergy analysis in the catchment area of Dez in Iran in the crop year 2019–2020. For this purpose, a total of 400 questionnaires from wheat and maize farmers were collected based on a simple random sampling method. The results of evaluating the ecological footprint method of wheat and maize cultivation in the study area at the level of one hectare were 3.50 and 4.66 global hectares, respectively. Also, the results of total emergy inputs for the ecological system of wheat and maize production were 1.60E+16 and 2.55E+16 sej ha−1 per year, respectively. This study showed that the two methods EF and EA are complementary. The evaluation results of both sustainability indices were very close to each other so both cultivation systems were environmentally unsustainable. We also found that the ecosystem of the irrigated wheat production system is more desirable than the ecosystem of the maize production system in terms of yield, renewability, and environmental sustainability. Since both cropping systems are strongly affected by the purchased inputs (more than 95%), as a result, they create a high environmental pressure, which shows the apprehensive condition of the current agricultural production systems in Iran. This study is the first study from Iran that uses these two tools simultaneously to determine the sustainability assessment of two strategic products of the region.

Whole farm planning raises profit despite burgeoning climate crisis

The climate crisis challenges farmer livelihoods as increasingly frequent extreme weather events impact the quantum and consistency of crop production. Here, we develop a novel paradigm to raise whole farm profit by optimising manifold variables that drive the profitability of irrigated grain farms. We build then invoke a new decision support tool—WaterCan Profit—to optimise crop type and areas that collectively maximise farm profit. We showcase four regions across a climate gradient in the Australian cropping zone. The principles developed can be applied to cropping regions or production systems anywhere in the world. We show that the number of profitable crop types fell from 35 to 10 under future climates, reflecting the interplay between commodity price, yield, crop water requirements and variable costs. Effects of climate change on profit were not related to long-term rainfall, with future climates depressing profit by 11–23% relative to historical climates. Impacts of future climates were closely related to crop type and maturity duration; indeed, many crop types that were traditionally profitable under historical climates were no longer profitable in future. We demonstrate that strategic whole farm planning of crop types and areas can yield significant economic benefits. We suggest that future work on drought adaptation consider genetic selection criteria more diverse than phenology and yield alone. Crop types with (1) higher value per unit grain weight, (2) lower water requirements and (3) higher water-use efficiency are more likely to ensure the sustainability and prosperity of irrigated grain production systems under future climates.

Indonesia Rice Irrigation System: Time for Innovation

Indonesia is likely to face a water crisis due to mismanagement of water resources, inefficient water systems, and weak institutions and regulatory organizations. In 2020, most of the fresh water in Indonesia was used for irrigation (74%) to support the agricultural sector, which occupies 30% of the total land area in Indonesia. Of all agricultural commodities, rice is one of the major and essential commodities, as it is the basic staple food for almost every Indonesian. However, in 2018, the Ministry of Public Works and Housing (MoPWH) reported that 46% of Indonesian irrigation infrastructure is moderately to heavily damaged. Looking at how irrigation can be very crucial to the welfare of Indonesian population, this study conducted an extensive literature review of the historical, current, and future management of irrigated rice production systems in Indonesia. This study has clearly shown that the irrigation systems in Indonesia have existed for thousands of years and, thus, there is a close relationship between irrigation and the socio-cultural life of the Indonesian population. Aside from how climate change influences water availability for irrigation, rice production with a constant water ponding system has been found to contribute to climate change, as it emits methane (CH4) and other greenhouse gases from agricultural fields of Indonesia. Therefore, the required modernization of irrigation systems in Indonesia needs to consider several factors, such as food demands for the increasing population and the impact of irrigated agriculture on global warming. Multi-stakeholders, such as the government, farmers, water user associations (WUA), and local research institutions, need to work together on the modernization of irrigation systems in Indonesia to meet the increasing food demands of the growing population and to minimize the impacts of agriculture on climate change.

Identifying low risk and profitable crop management practices for irrigated Teff production in northwestern Ethiopia

Teff (Eragrostis tef (Zucc.) Trotter) is one of the most important staple crops in Ethiopia. However, the optimal agronomic practices of the crop under irrigation remain unclear. The objectives of this study were to evaluate the Cropping System Model (CSM)-NWheat-Teff and to determine the optimum planting date, nitrogen (N) application rate, and irrigation threshold in northwestern Ethiopia. The model was calibrated and evaluated using published data from field experiments conducted from 1996 to 1998 in the Adet and Bichena districts and from 2001 to 2003 in the Dangila district. The model was then used to simulate different planting dates (Jan 1, Jan 15, Feb 1, Feb 15, Mar 1), N rates (0, 20, 40, 60, 80 kg ha−1), and irrigations (irrigation when required/automated, 50% and 25% available soil moisture thresholds) levels for Adet, Bichena and Dangila using historical weather data (1983–2020). The model was able to simulate teff phenology and yield adequately as indicated by low root mean square error (RMSE) and a high index of agreement (d) for both the calibration and evaluation datasets. Grain and straw yield increased with increasing N, but the rate of increment was higher under irrigation when required (automated) compared to 50% and 25% thresholds. Late planting (March 1) at Adet and early planting (January 1 and February 15) at Bichena and Dangila resulted in the highest profit with a minimum variability in output. The combined use of 80 kg N ha−1 and irrigation when required gave the most profitable option with low risk of irrigated teff production at the three sites studied. This study showed that the new CSM-NWheat-Teff model can be used to optimize agronomic practices for irrigated teff production systems in Ethiopia. Further research is needed to improve model performance in predicting teff yield for contrasting biophysical and socio-economical environments.

Farm-planning under risk: An application of decision analysis and portfolio theory for the assessment of crop diversification strategies in horticultural systems

CONTEXTEven though diversification of horticultural production systems allows farmers to cope with risks and uncertainties, strategies for raising profitability usually aim to improve the productivity of monocultures rather than pursuing diversification. Horticultural production systems are often highly diversified in terms of land use and planted crops. OBJECTIVEAssessing the economic prospects of these complex systems requires quantification of productivity and related risks for individual crops as well as an assessment of the benefits from diversification. Here we demonstrate the implementation of a systematic assessment for irrigated production systems in the Sinú Valley of the Colombian Caribbean. METHODSWe used participatory modeling approaches, focus group discussions and interviews to collect relevant qualitative and quantitative information from farmers. Quantitative information associated with input variables was elicited as probability distributions. Farmers were trained in estimation techniques, enabling them to provide reliable quantitative assessments of production-related variables. RESULTS AND CONCLUSIONSThe model and elicited values for input variables were used to build a probabilistic simulation that allowed for estimating the expected income from horticultural crops and identifying portfolio strategies based on currently available horticultural options. The irrigated horticultural production systems of the Sinú Valley in Colombia contain four main crops. All farmers cultivate eggplants and sweet peppers but they have specific preferences for yardlong beans and papaya. These preferences reflect two crop diversification strategies attuned to farmers' resources. Yardlong beans are a short-term (3 months), low-risk, and low-profit investment (a tenth of the best crop option) while papaya is a long-term crop (18 months) of high-risk and profit. Yardlong beans are planted by smallholders with limited financial resources as a way to subsist and produce additional cash that can be invested in riskier more profitable crop options (eggplants and sweet peppers). This strategy describes a transition from a secure option (3 standard deviations (SD)) to riskier options (6 SD or more) that can generate greater profits. The second strategy describes actions of wealthier smallholders that can invest in short-lived perennial crops including papaya, sweet pepper and eggplants. This three-crop portfolio cuts production risks roughly in half (from 10 SD for the riskier option to 5 SD in the portfolio). SIGNIFICANCEWe expect our decision analysis approach to prove useful in assessing other horticultural systems but also for the assessment and identification of new crop options to be incorporated in diversified systems. Our decision analysis approach can also be used to represent diversification in other whole-farm planning scenarios, e.g. when it comes to rotations of field crops, integrated livestock farms, cut-flower farming or agroforestry systems.

Sowing Dates Influence Incidence of Bacterial Leaf Streak and Rice Yield under Irrigated Production Systems in Burkina Faso

Bacterial leaf streak (BLS) caused by Xanthomonas oryzae pv. oryzicola (Xoc) is a disease that is prevalent in the main rice-growing sites of Burkina Faso. It causes foliar incidences of up to 100% on some crop varieties and is variable from season to season. Control methods include the use of resistant varieties, integrated pest management and good cultural practices, including sowing dates. Indeed, data on the influence of sowing dates on the incidence of BLS are not well known, especially under the rice cultivation conditions in Burkina Faso.

Risk Factors in Various Climates of Wheat Production in Western Iran: Experts’ Opinions

Agriculture is the origin of existence and survival in any society. However, this sector is always associated with risk and uncertainty, and farmers are faced with many challenges. Therefore, the main aim of this research was to explore the (production) risk factors of irrigated wheat production systems among farmers in Kermanshah province, Iran. The exploratory nature of this study on the one hand and the need for expert judgment on the other hand necessitated a Delphi research design. Thus, this study utilized a three-round Delphi technique. The population comprised of 10 subject-matter experts (SME) and 32 agricultural extension experts in two climates (warm and semi-arid and cold and moderate) in seven counties in Kermanshah province. A purposeful (complete) sample of 42 experts in the agricultural field participated in this study. Data were collected using a questionnaire designed on the basis of the Delphi technique. The findings indicated that, after three rounds of Delphi technique, the panel members reached a consensus on 75 factors which were categorized into biological, natural, managerial, and technological-structural groups for production risk. The results of this research provide useful insights for researchers, extension agents, and farmers.

Cover crop water use and corn silage production in -semi-arid irrigated conditions

Cover crops can increase crop water productivity (CWP) and succeeding crop yield. However, cover crops adoption in the Southern High Plains of USA is slow due to limited water available for crop production. This study evaluated the effects of winter cover crops on soil water dynamics, corn silage yield and nutritive values, and corn silage CWP in a semi-arid irrigated condition. Three winter cover crop mixtures: grasses + brassicas + legumes (GBL), grasses + brassicas (GB), grasses + legumes (GL), and control or no cover crop (NCC) were evaluated for soil water storage, cover crop biomass, corn silage yield, nutritive values, and crop evapotranspiration (ET), and the cover crop-corn silage system water productivity (SWP) under a no-till irrigated corn silage production system. All cover crop treatments reduced soil water storage before their termination in both years. However, water storage was higher for all cover crop treatments than for NCC during corn growth. Average CWP for corn was improved by 14–29% with cover crop mixtures over the NCC. Corn silage yield among cover crop treatments was 9–26% higher than NCC. Nutritive value components of cover crops such as non-fat carbohydrates, relative forage quality, and Ca and Mg were higher in the GBL and GL mixtures than the GB in one of the two years. This study demonstrated increased corn silage yield and water productivity with cover cropping. Cover crops mixtures with legumes could offer a high-quality alternative forage for crop-cattle integrated systems, including dairy producers in the Southern High Plains region.

SUSTAINABILITY OF ORGANIC AND CONVENTIONAL IRRIGATED SYSTEMS BASED ON FAMILY FARMING

This study was carried out at two farms: Carcará Farm, certified by Associação de Certificação Instituto Biodinâmico, and at Estufa Limoeiro Farm, of conventional cultivation. They were located in Guaraciaba do Norte, Ceará, at the geographic coordinates 04°10’52” South, 40°49’41” West, and elevation of 885 m. The main objective of this research was to compare, based on economic, social and environmental indicators, two irrigated production systems, one organic one and a conventional. Data were collected through interviews with the farmers. Generation of jobs, added value, and the farmer’s income were analyzed as variables associated with the socioeconomic dimensions. For the environmental analysis, the biological activity of the soil was evaluated using the variables organic carbon (OC), microbial biomass carbon (MBC), soil basal respiration (SBR), microbial quotient (qMIC) and metabolic quotient (qCO2). The organic cultivation system provided a generation of direct jobs per unit area three times higher than average of irrigated agriculture in the Brazilian semi-arid region, characterizing it as a system of greater social contribution. When compared to the conventional system, the organic farming system showed a lower risk associated with the economic dimension. The production unit with organic cultivation had higher environmental sustainability since the soil is in more satisfactory physical and chemical conditions for the development of microorganisms.

Impacto ambiental de diferentes sistemas de produção agrícola

The efficient use of natural resources in production systems is essential for achieving ecological balance and sustainability in these systems. Current agricultural production systems have intensified the use of fertilisers and pesticides that contribute to an increase in energy flow, accelerating the process of degradation. The aim of this study was to evaluate, using emergy analysis, the environmental performance of different irrigated production systems for different sources of water, energy and fertiliser, and of rainfed systems under different types of soil preparation. The irrigated systems were studied in the experimental area of the Sewage Treatment Station (ETE) in Tianguá, Ceará (CE), and the rainfed models at the Fazenda Normal Farm in Quixeramobim, CE. Emergy analysis basically consists of three stages: construction of the systemic energy flow diagram, elaboration of the emergy evaluation table, and calculation of the emergy indicators. A mean value of 0.04 was found under the rainfed production systems, which shows less environmental stress compared to the irrigated systems, 0.30. The influx of economic resources into agricultural systems increases the environmental load and reduces renewability. Treated domestic effluent and photovoltaic solar energy afforded an increase in emergy yield and in the environmental sustainability of the production models.

Optimization of rapeseed production using exergy analysis methodology

The exergy analysis helps to determine the energy losses of different inputs through identifying the actual amount of energy consumed in a process. In this regard, a new approach was applied in this study to predict and optimize the rainfed production systems (RPS) and irrigated production systems (IPS) of rapeseed in the north of Iran, by using exergy analysis methodology. Two indices of cumulative degree of perfection (CDP) and renewability index (RI) were used to evaluate the sustainability of systems. The Support Vector Machine (SVM) and Multi-Objective Genetic Algorithm (MOGA) were also employed to predict and optimize the rapeseed production systems, respectively. In the study of conventional system, CDP and RI were determined to be 2.19 and 0.72, on average, respectively, in which, the values of both indices were higher in the RPS than IPS. Optimization results indicated that by reducing the consumption of irrigation water, electricity and biocides as well as increasing the use of chemical fertilizers, farmyard manure and diesel fuel, the yield increased by 24.55%. Sustainability assessment in optimal scenario revealed that CDP and RI increased to 2.75 and 0.81, respectively. As a result, under optimal conditions, the production process becomes more environmentally friendly.

Economic and environmental assessment of tobacco production in Northern Iran

Environmental and economic aspects of a production system are two main pillars to study the sustainability of the system. In this regard, the purpose of this study was the economic and environmental assessment of tobacco (Nicotiana tabacum) production in rainfed and irrigated systems in northern Iran. The data were collected from 133 rainfed and 176 irrigated tobacco farms in three provinces of Mazandaran, Golestan, and Guilan in Iran. The standard method of life cycle assessment (LCA) provided by ISO 14040-44 was used to study the environmental impacts. Four economic indices, including gross income, net income, benefit to cost ratio, and economic productivity, were examined for the economic analysis of the cropping systems. In the study of environmental impacts, the average value ​​of global warming input was 2624.11 kgCO2eq. The comparison of rainfed and irrigated systems revealed that the rainfed system in all impact categories had the highest environmental impact. Moreover, emissions from on-site operations and the use of two inputs of natural gas and chemical fertilizers had the highest effect on characterization indices. The results also showed that tobacco production had the highest adverse effects on resources and a significant amount of fossil fuels used in the production process had the largest share in increasing this damage group. Economic analysis also highlighted that the average net income and benefit to cost ratio were 6646.86 $ ha−1 and 2.27. The irrigated system had higher values of the indices than the rainfed system, indicating the higher profitability of the irrigated production system.

Net positive soil water content following cover crops with no tillage in irrigated semi-arid cotton production

Conservation management practices such as no-tillage and cover cropping can reduce soil erosion, enhance soil biological activity, increase water capture and storage, and sequester C. Cover crops, however, utilize stored soil water during the winter months, and the water depletion is thought to have negative impacts on the subsequent cotton (Gossypium hirsutum L.) crop in semi-arid ecoregions where water resources are limited. The objective of this research was to quantify the long-term impacts of conservation tillage and cover crop use on volumetric water content of soil in an irrigated cotton production system. Soil water was measured in a long-term (established 1998) conservation system in Lamesa, TX and water dynamics during the 2015–2017 growing seasons are presented here. Volumetric water content was reduced by cover crops prior to their termination but was replenished by spring precipitation and deficit irrigation prior to planting cotton. A stepwise regression analysis was used to determine changes in soil water at depth. In each of the study years, soil water increased more with no-tillage following cover crop termination and decreased less during cotton growth than the conventionally tilled system. Cotton water use efficiency was not significantly different between treatments in any year. Results from this study challenge the concept that winter cover crops result in reduced in-season soil water in irrigated systems, a supposition that has limited adoption of conservation tillage and cover crop use on the Texas High Plains.

Yield of Whole, Polished Whole Grains and Degree of Whiteness of Rice for Japanese Cuisine Obtained in Flood Irrigation System

New rice cultivars with grains for Japanese cuisine have been launched in order to add value to irrigated rice production systems in the country. The objective was to evaluate the yield of polished and whole grains of cultivar BRS 358, at harvest and at six months of storage grown under a continuous irrigation system. The experiment was conducted in a lowland area, in Cantá-RR, with application of 150 kg ha-1 of N, 50% at the base and 50% at 45 days after emergence. Three harvest seasons were carried out: 38 days after flowering - DAF (A01), 45 DAF (A1) and 52 DAF (A2), to evaluate the yield of whole and polished whole grains, at harvest and at 6 months of storage. The results showed that application of N, promoted higher yield of whole grains, with 65% yield at harvest, and when stored for six months at room temperature, yield above 75%. For the polished whole grain yield, the best harvest range is 38-45 DAF, with whole grain yield above 50% and regardless of the harvesting and storage time of the grains the total whiteness is above 55%.

Grass Buffer Strips Improve Soil Health and Mitigate Greenhouse Gas Emissions in Center-Pivot Irrigated Cropping Systems

Declining water resources and soil degradation have significantly affected agricultural sustainability across the world. In the southern High Plains of USA, buffer strips of perennial grasses alternating with cultivated corn strips were introduced in center-pivot irrigated crop fields to increase agronomic production and ecosystem services. A study was conducted to evaluate soil carbon (C) and nitrogen (N) dynamics, greenhouse gas (GHG) emissions, and soil health benefits of integrating circular grass buffer strips in the center-pivot irrigated corn production system. Multiple parameters were assessed in the grass buffer strips, and at distances of 1.52, 4.57, and 9.14 m away from the edges of grass strips in corn strips. While grasses in the buffer strips depleted N compared to corn strips, potential C mineralization (PCM) was 52.5% to 99.9% more in grass strips than in corn strips. Soil microbial biomass C (MBC) content was 36.7% to 52.5% greater in grass strips than in corn strips. Grass buffer also reduced carbon dioxide (CO2) and nitrous oxide (N2O) emissions from corn strips. Grass buffer strips can improve soil health and sustainability in center-pivot irrigated cropping systems by increasing soil C components and reducing GHG emissions.

Soil Carbon Sequestration in Rainfed and Irrigated Production Systems in a New Brazilian Agricultural Frontier

Western Bahia, part of a large Brazilian agricultural frontier, is located mainly in fragile, sandy soils in a tropical seasonal climate with dry winters, characteristics that facilitate soil carbon loss. This study evaluates whether rainfed and irrigated agriculture in Western Bahia were able to sequester carbon and re-establish the soil organic carbon content (SOCC) lost due to land use change. Between 2010 and 2018, a total of 5469 soil samples were collected in the 0.00–0.20 m soil layer from nine farms and were used to calculate the annual rate of SOCC variation. The most recent SOCC measured in plots where land use change occurred 20 years ago was compared with the SOCC measured in areas of native vegetation (Cerrado). Results showed that (i) irrigated sandy agricultural lands replenished SOCC to the level observed in native vegetation by 20 years after a land use change event and are still capturing carbon at a significant rate, (ii) clayey, rainfed agricultural lands also sequester carbon, but these soils are not representative of the region, and (iii) sandy, rainfed agricultural lands, the predominant soil type and management practice in Western Bahia, are not a sink of CO2.

Water productivity of irrigated maize production systems in Northern China: A meta-analysis

Understanding water productivity (WP) on a regional scale is useful for identifying and managing inefficiencies in irrigated crop production systems. However, relevant WP analyses are not available for maize production systems in China. A meta-analysis was conducted of maize WP in Northern China that included 2354 observations from 282 articles published between January 2000 and March 2018. Our goal was to quantify the current WP and its constraining factors, and estimate the boundary function for WP in the different maize agro-ecological zones of Northern China. The Northern China average WP across the large set of field experiments was 22.3 kg ha–1 mm–1, with Northeast China (NE, 25.8 kg ha–1 mm–1) > North China Plain (NCP, 22.3 kg ha–1 mm–1) ≈ Northwest China (NW, 21.6 kg ha–1 mm–1). The boundary function for WP had slopes of 42.5, 36.8 and 40.4 kg ha−1 mm−1 for NW, NCP and NE, respectively. The WP was significantly correlated with latitude, vapor pressure deficit, N application rate, seasonal average temperature, experimental regions and years. WP was increased by optimal irrigation, soil surface with plastic mulch, deep tillage, straw incorporation into the soil, ridge planting, and the application of super absorbent polymer. In this study, we provided both reference WP values, recommendations to achieve higher WP and identification of regions with opportunities for improvement.

Response Mechanism of Cotton Growth to Water and Nutrients under Drip Irrigation with Plastic Mulch in Southern Xinjiang

The effects of water and nutrient control measures on the cotton plant height, stem diameter, biomass, seed yield, and soil moisture under an irrigated plastic mulch production system were studied. Using field experiments in the 2018 cotton-growing season, 6 fertilization treatments (30-10.5-4.5 (N-P2O5-K2O), 24-8.4-3.6 (N-P2O5-K2O), 20-7-3 (N-P2O5-K2O), 16-5.6-2.4 (N-P2O5-K2O), 10-3.5-1.5 (N-P2O5-K2O), and 0-0-0 (N-P2O5-K2O) kg/mu) and 6 deficit irrigation treatments (40% PET, 60% PET, and 80% PET) were established at the cotton budding and flowering stages. Analysis of variance (ANOVA) (P<0.05) was used to evaluate the significant differences among the treatments. The results showed that the effects of the water and nutrient control measures were obvious. The irrigation water use efficiency (IWUE) was the highest under the 80% deficit irrigation (T7) treatment at the flowering stage (2.62 kg/m3). Increases in cotton plant height and stem diameter were promoted by mild or moderate deficit irrigation at the flowering stage, but normal growth and development were affected by severe deficit irrigation at any growth stage. The growth indexes of cotton increased with increasing fertilization, but significant differences between each fertilization gradient were not obvious. At the same time, excessive fertilization not only had a positive effect on the LAI (leaf area index) and yield but also caused fertilizer waste and unnecessary cotton growth. The cotton seed yield and single boll yield reached their highest values (566 kg/mu) under the 1.2 times fertilizer treatment (T9), but the 0.8 times fertilizer treatment had the highest IWUE among the nutrient control treatments (1.91 kg/m3). Therefore, it is suggested that deficit irrigation at 60~80% of the potential evapotranspiration (PET) at the flowering stage and 16-5.6-2.4 (N-P2O5-K2O) fertilizer be applied as an optimal water and nutrient management strategy to maximize the seed cotton yield, IWUE, and overall growth and development of cotton.

Long-term effects of dryland and irrigation production systems on soil Fusarium communities in wheat

Characterization and quantification of Fusarium communities and other microorganisms are crucial for understanding Fusarium ecology and management of root diseases of wheat. Fusarium communities in soils and on wheat roots from 12 Nebraska farms under dryland, and irrigated production systems were investigated using dilution plating assays, denaturing gradient gel electrophoresis (DGGE), and subsequent DNA sequence analysis. Results showed that the population densities of Fusarium in soils were significantly higher under dryland than irrigated production systems, and Pythium, Trichoderma, and Pseudomonas spp. in soils and on wheat roots were significantly lower in dryland systems. However, colonization of Fusarium spp. on the root surface, Shannon diversity indices and richness of Fusarium spp. in soils were generally higher in soils under dryland than irrigation systems based on the soils from 12 farms. Also, Shannon diversity indices and richness of Fusarium spp. in soils were significantly higher in soils under non-irrigated compared to adjacent irrigated centre-pivot field. Canonical correspondence analysis (CCA) showed that soil Fusarium communities generally formed two groups with overlap based on dryland and irrigation systems with 12 farm samplings, whereas the Fusarium communities formed two distinct groups in soils under irrigated and non-irrigated section of the centre pivot field. Moreover, dryland and irrigation systems affected several soil chemical properties. In general, soils under long-term irrigation tend to reduce populations and diversities of Fusarium spp. and increase populations and diversities of Pythium spp. compared with dryland systems.