Corrigendum: Sensor-based precision nutrient and irrigation management enhances the physiological performance, water productivity, and yield of soybean under system of crop intensification.

[This corrects the article DOI: 10.3389/fpls.2023.1282217.].

Alternatives to maize monocropping in Mediterranean irrigated conditions to reduce greenhouse gas emissions.

Winter legume cover crops or double-cropping in high N-fertilizer maize-based sprinkler-irrigated systems enhance agroecosystem diversity and potentially increase yields. However, the effects on direct N2O emissions and global warming potential (GWP) have not been fully established. For two years, in the Ebro Valley (Spain), four maize-based systems consisted of: long-season maize (Zea mays) with winter fallow period (F-LSM) the reference system; or after a leguminous cover crop (common vetch, Vicia sativa) (CC-LSM); and short-season maize after a cereal crop (barley, Hordeum vulgare) (B-SSM) or after a leguminous crop (pea, Pisum sativum) (P-SSM). They were assessed in terms of productivity, direct greenhouse gasses emissions (GHG: N2O, CH4, CO2), and global warming potential (GWP). Direct GHG emissions were measured using the static chamber technique, while soil parameters were monitored. Crop yields and nitrogen uptake were also quantified. GHG emissions linked to management and inputs were calculated to obtain GWP and greenhouse gas intensity (GHGI). The most productive system (B-SSM) obtained the highest direct (79 %, 35 %, and 30 % higher than the F-LSM, P-SSM, and CC-SSM, respectively) and scaled N2O emissions. The P-SSM system had similar N-uptake-scaled emissions to the monocropping (MC) systems. Irrigation, fertilizer, and farm operations accounted for the 26 %, 31 %, and 27 % of the total indirect emissions, respectively. Fertilizer production-related emissions in B-SSM and F-LSM systems were 172 % and 45 % higher than the average emissions in the systems with legumes (461 kg CO2eq. ha-1). Diversified systems lead to slightly higher GHGI values than the reference system (F-LSM). However, no differences were found between the F-LSM and P-SSM systems in GWP (4521 and 5512 kg CO2-eq. ha-1, respectively) or GHGI (144 and 158 kg CO2-eq. ha-1, respectively). The P-SSM system may be a potential alternative for increasing the diversification of maize-based irrigated agrosystems without increasing GHG emissions.

Effects of fresh and field-aged holm-oak biochar on As, Cd and Pb bioaccumulation in different rice growing environments.

Arsenic, Cd, and Pb environmental fate is influenced when the traditional permanent flooding rice production systems are replaced by water-saving and soil conservation practices, urging for additional strategies that avoid their bioaccumulation in rice grain. The aim of this two-years field study was to evaluate the effects of fresh and field-aged biochar on As, Cd, and Pb bioaccumulation, and on As speciation, in rice grain produced in different growing environments (flooding versus sprinkler and conventional tillage versus direct seeding). Biochar produced from holm-oak pruning residues (pyrolysis at 550 °C, 48 h), in a single application (28 Mg ha-1), reduced As bioaccumulation in rice grain in the permanent flooding system to non-quantifiable concentrations (e.g., from 0.178 mg kg-1 to <0.04 mg kg-1, for inorganic-As, respectively), an effect which remained under field-aging conditions, increasing rice commercial value. When adopting sprinkler irrigation, the undesirable increase in Cd bioaccumulation in rice, relatively to the anaerobic system, was counteracted by biochar application, reducing its bioaccumulation in kernels between 32 and 80 %, allowing a simultaneous control of metals and metalloids bioaccumulation in rice. The bioaccumulation of Pb was also prevented with biochar application, with a reduction in its concentration four- to 13-times, in all the management systems, relatively to the non-amended plots, under fresh biochar effects. However, Pb immobilization decreased with biochar field-aging, indicating that the biochar application may have to be repeated to maintain the same beneficial effect. Therefore, the present study shows that the implementation of sprinkler irrigation with holm-oak biochar could reduce the risk of heavy metals(loids) bioaccumulation in rice grains and, thereby, ensuring food safety aspects, particularly under fresh biochar effects.

Combined use of biochar and alternative management systems for imazamox induced pollution control in rice growing environments.

Imazamox (IMZX) is a persistent herbicide having probable risks for non-target organisms in the environment and water contamination. Alternatives to conventional flooding rice production, including biochar amendment, may induce changes in soil properties which can greatly modify the environmental fate of IMZX. This two-year study is the first to evaluate how tillage and irrigation practices, with or without fresh or aged biochar (Bc), that are alternatives to conventional rice production impact IMZX's environmental fate. The treatments were: conventional tillage and flooding irrigation (CTFI), conventional tillage and sprinkler irrigation (CTSI), no-tillage and sprinkler irrigation (NTSI), and the corresponding Bc-amendment treatments (CTFI-Bc, CTSI-Bc, and NTSI-Bc). Fresh and aged Bc amendment decreased IMZX's sorption onto the soil in tillage treatments, with Kf values decreasing 3.7 and 4.2-fold (fresh case) and 1.5 and 2.6-fold (aged case) for CTSI-Bc and CTFI-Bc, respectively. The transition to sprinkler irrigation reduced IMZX persistence. Overall, Bc amendment also reduced chemical persistence with half-life values decreasing 1.6 and 1.5-fold for CTFI and CTSI (fresh year) and 1.1, 1.1, and 1.3-fold for CTFI, CTSI, and NTSI (aged year), respectively. Sprinkler irrigation reduced IMZX leaching by up to a factor of 2.2. The use of Bc as amendment led to a significant decrease in IMZX leaching only under tillage conditions, but notable in particular for the CTFI case where leaching losses were reduced in the fresh year from 80% to 34% and, in the aged year, from 74% to 50%. Hence the change in irrigation from flooding to sprinkler either alone or in combination with the use of Bc (fresh or aged) amendment could be considered an effective way to sharply mitigate IMZX contamination of water in environments where rice is grown, particularly in those managed with tillage.

The food-energy-water-carbon nexus of the rice-wheat production system in the western Indo-Gangetic Plain of India: An impact of irrigation system, conservational tillage and residue management.

The conventional rice-wheat system in the western Indo-Gangetic plain of India is energy and water intensive with high carbon footprint. The transition towards resource-efficient eco-friendly production technologies with lower footprint is required for inclusive ecological sustenance. A five-year (2016-17 to 2020-21) field experiment was conducted in RWS with hypothesis that pressurized irrigation systems [drip (DRIP) and mini-sprinkler (MSIS)] in conservation tillage [reduced (RT)/zero (ZT)] and crop residue management [incorporation (RI)/mulch (RM)] might result in higher resource use efficiency with lesser carbon footprint compared to conventional system. Experiment consisted five treatments namely (1) puddled transplanted rice followed by conventionally tilled wheat (PTR/CTW), (2) DRIP irrigated reduced till direct seeded rice (RTDSR) followed by zero-till wheat with 100 % rice residue mulching (ZTW + RM) (DRIP-RTDSR/ZTW + RM), (3) surface irrigated RTDSR followed by ZTW + RM (SIS-RTDSR/ZTW + RM), (4) MSIS irrigated RTDSR followed by ZTW + RM (MSIS-RTDSR/ZTW + RM), and (5) MSIS irrigated RTDSR with 1/3rd wheat residue incorporation followed by ZTW + RM (MSIS-RTDSR + RI/ZTW + RM). The pressurized irrigation system in RWS established under conservational tillage and residue management (DRIP-RTDSR/ZTW + RM and MSIS-DSR + RI/ZTW + RM) produced at par system productivity compared to PTR/CTW. Substantial nitrogen (79-114 ka ha-1) and irrigation water (536-680 mm) savings under pressurized irrigation systems resulted in 41-64 % higher partial factor productivity of nitrogen with 48-61 % lower water footprint. These systems had lower energy consumption attaining 15-21 % higher net energy, 44-61 % higher energy use efficiency, and 31-38 % lower specific energy. Efficient utilization of farm inputs caused lower greenhouse gas emission (39-44 %) and enhanced carbon sequestration (35-62 %) resulting 63-76 % lower carbon footprint over PTR/CTW. The information generated here might useful in developing policies for resource and climate-smart food production system aiming livelihood security and ecological sustainability in the region. Further, trials are needed for wider adaptability under different climate, soil and agronomic practices to develop site-specific climate smart practices.

Sensor-based precision nutrient and irrigation management enhances the physiological performance, water productivity, and yield of soybean under system of crop intensification.

Sensor-based decision tools provide a quick assessment of nutritional and physiological health status of crop, thereby enhancing the crop productivity. Therefore, a 2-year field study was undertaken with precision nutrient and irrigation management under system of crop intensification (SCI) to understand the applicability of sensor-based decision tools in improving the physiological performance, water productivity, and seed yield of soybean crop. The experiment consisted of three irrigation regimes [I1: standard flood irrigation at 50% depletion of available soil moisture (DASM) (FI), I2: sprinkler irrigation at 80% ETC (crop evapo-transpiration) (Spr 80% ETC), and I3: sprinkler irrigation at 60% ETC (Spr 60% ETC)] assigned in main plots, with five precision nutrient management (PNM) practices{PNM1-[SCI protocol], PNM2-[RDF, recommended dose of fertilizer: basal dose incorporated (50% N, full dose of P and K)], PNM3-[RDF: basal dose point placement (BDP) (50% N, full dose of P and K)], PNM4-[75% RDF: BDP (50% N, full dose of P and K)] and PNM5-[50% RDF: BDP (50% N, full P and K)]} assigned in sub-plots using a split-plot design with three replications. The remaining 50% N was top-dressed through SPAD assistance for all the PNM practices. Results showed that the adoption of Spr 80% ETC resulted in an increment of 25.6%, 17.6%, 35.4%, and 17.5% in net-photosynthetic rate (Pn), transpiration rate (Tr), stomatal conductance (Gs), and intercellular CO2 concentration (Ci), respectively, over FI. Among PNM plots, adoption of PNM3 resulted in a significant (p=0.05) improvement in photosynthetic characters like Pn (15.69 µ mol CO2 m-2 s-1), Tr (7.03 m mol H2O m-2 s-1), Gs (0.175 µmol CO2 mol-1 year-1), and Ci (271.7 mol H2O m2 s-1). Enhancement in SPAD (27% and 30%) and normalized difference vegetation index (NDVI) (42% and 52%) values were observed with nitrogen (N) top dressing through SPAD-guided nutrient management, helped enhance crop growth indices, coupled with better dry matter partitioning and interception of sunlight. Canopy temperature depression (CTD) in soybean reduced by 3.09-4.66°C due to adoption of sprinkler irrigation. Likewise, Spr 60% ETc recorded highest irrigation water productivity (1.08 kg ha-1 m-3). However, economic water productivity (27.5 INR ha-1 m-3) and water-use efficiency (7.6 kg ha-1 mm-1 day-1) of soybean got enhanced under Spr 80% ETc over conventional cultivation. Multiple correlation and PCA showed a positive correlation between physiological, growth, and yield parameters of soybean. Concurrently, the adoption of Spr 80% ETC with PNM3 recorded significantly higher grain yield (2.63 t ha-1) and biological yield (8.37 t ha-1) over other combinations. Thus, the performance of SCI protocols under sprinkler irrigation was found to be superior over conventional practices. Hence, integrating SCI with sensor-based precision nutrient and irrigation management could be a viable option for enhancing the crop productivity and enhance the resource-use efficiency in soybean under similar agro-ecological regions.

Environmental fate and efficiency of bispyribac­sodium in rice soils under conventional and alternative production systems affected by fresh and aged biochar amendment.

Irrigation and tillage practice alternatives to conventional flooding production, with or without organic amendments, are attracting great interest to adapt rice cultivation to climate change. However, they can alter the behaviour of pesticides and their efficiency against weeds. A two-year field experiment was conducted to investigate how the environmental fate and the weed control efficiency (WCE) of bispyribac­sodium (BS) were influenced by biochar produced from holm oak prunings (BHO) testing both the fresh and the aged effects. The treatments were: flooding irrigation and tillage (FT), sprinkler irrigation and tillage (ST), sprinkler irrigation and no-tillage (SNT), and the corresponding homologues with BHO addition (FT-BHO, ST-BHO, and SNT-BHO, respectively). Fresh BHO amendment decreased the sorption of BS onto the soil in all treatments, while, after aging, it also decreased sorption in FT-BHO (1.3-fold) but increased it in SNT-BHO and ST-BHO (1.1-fold). BHO addition reduced BS persistence under non-flooding and flooding incubation conditions, except for FT under the former condition for which t1/2 increased ≈1.5-fold in both years. The addition of BHO led to a decrease in BS leaching from 58.3 % and 44.6 % and from 70.4 % and 58.1 % in ST and FT to 50.1 % and 38.3 % and 63.6 % and 50.3 % in the homologue amended soils for the fresh and aged years, respectively. While fresh BHO addition decreased the WCE of BS in SNT-BHO, ST-BHO, and FT-BHO on average by a factor of 1.5, with aged BHO there was only such a decrease (by a factor of 1.4) in FT-BHO. The use of BHO could be effective for reducing water contamination by BS in flooding or sprinkler irrigation rice farming as long as conventional tillage is used. But it may also contribute to greatly reducing the herbicide's efficiency, although with time to allow aging, this reduction would only persist under conventional flooding production.

Water Application Method Influences Survival or Growth of Escherichia coli on Bulb Onions during Field Curing.

ABSTRACT: The impact of water application method on bacterial survival at or after the final irrigation was evaluated in bulb onions during commercially relevant field drying (curing). A three-strain rifampin-resistant cocktail of Escherichia coli was introduced to onions via a single overhead spray application in two separate trials (5.22 [trial 1] or 2.40 [trial 2] log CFU per onion) 2 to 3 days after the final irrigation. Onions were lifted from the soil 8 days after spray inoculation and, in some cases, foliage was removed (topping); onions remained in the field for an additional ca. 2 weeks (total ca. 3 weeks of curing). E. coli populations declined on the onions in the first 4 h after spray inoculation. E. coli was recovered from 38 (48%) or 28 (35%) of 80 whole-onion enrichments at the end of curing in trials 1 or 2, respectively. Topping did not significantly impact the percentage of E. coli-positive onions detected at the end of curing. From 8 h to 21 days, E. coli populations on positive onions ranged from 1 CFU per onion to 7 log CFU per onion in both trials, representing a potential risk of E. coli growth with overhead application of contaminated water at the end of onion production. In trial 2, additional rows of onions were inoculated via a 22-cm subsurface or surface drip irrigation line (1.94 log CFU/mL for 2.5 h). E. coli was detected in 0 (subsurface) and 4 (surface) of 50 whole-onion enrichments 3 h after the initiation of drip irrigation. Positive onions were detected at days 1 (4 of 50) and 7 (1 of 50) with subsurface drip inoculation, and at days 1 (7 of 50), 7 (2 of 50), and 14 (2 of 50) with surface drip inoculation. E. coli was not detected in whole-onion enrichments at the end of curing when inoculated by subsurface (0 of 50) or surface (0 of 50) drip irrigation. Application of contaminated water through drip irrigation, when coupled with field curing, results in low rates of contamination of bulb onions at the time of harvest.

Impact of sowing dates on the yield efficiency of upland rice cultivars

The choice of cultivars adapted to different regions and the determination of the best sowing dates are indispensable tools for crop development. This allows the installation of the crop in times favorable to its development, as well as cultivars that manage to reach their maximum yield potential. The objective of this study was to determine the best sowing dates and the cultivars that can adapt to the low-altitude Cerrado region and have the best development and yield efficiency. The experiment was conducted on a typical clayey dystrophic Red Latosol soil. The experimental design was in randomized blocks in a factorial scheme, comprised by four sowing dates during the spring/summer season (October, November, December, and February) and in each sowing date there were eight upland rice cultivars (BRS Esmeralda, ANa 6005, ANa 5015, IPR 117, IAC 203, IAC 500, ANa 7211 and BRSGO Serra Dourada) with four replicates. Sowing in October and November benefited the aerial dry mass and the spikelets fertility however, sowing in November provided higher plant height, which caused lodging in plants. Sowing in December caused the incidence of scald, mainly affecting the cultivar ANa 7211. For all cultivars, sowing in October favored the yield efficiency of upland rice in the low-altitude Cerrado, followed by sowing in November. The cultivars which demonstrated higher yield efficiency in the conditions of the region were BRS Esmeralda and ANa 5015.

Coupling sprinkler freshwater irrigation with vegetable species selection as a sustainable approach for agricultural production in farmlands with a history of 50-year wastewater irrigation.

Soil contamination and crop risks of heavy metal(loid)s are widely reported after the long-term irrigation of treated wastewater, causing an adverse influence on agricultural sustainability. Here, we collected soils after 50 years of wastewater irrigation to cultivate cabbage (Brassica pekinensis L.), rape (Brassica chinensis L.), carrots (Daucus carota L.), and potatoes (Solanum tuberosum L.), using surface and sprinkler irrigation with freshwater and wastewater. In general, we found the statistically insignificant influence of short-term freshwater irrigation on the soil and vegetable metal(loid) concentrations. Most of the vegetables had potential adverse health risks with the relatively lower risks in carrots and potatoes, and most of the risks were contributed by As and Cd. Nevertheless, we observed negligible health risks for all studied metal(loid)s in potatoes under the freshwater irrigations. Besides, compared to wastewater irrigations, freshwater irrigations produced lower Cd health risks in all four vegetable species. Sprinkler irrigation with freshwater was a favorable approach for reducing the uptake of metal(loid)s from soils and the metal(loid) concentrations in aboveground parts. Our study highlights the possibility of reducing vegetable metal(loid) risks in contaminated farmlands via a combined approach of coupling the short-term decrease in their levels in irrigation water with vegetable species selection.

Sprinkler irrigation in the production of safe rice by soils heavily polluted by arsenic and cadmium.

Among the factors affecting the bioaccumulation of As and Cd in rice, a key role is played by the irrigation methods. The sprinkler irrigation (SP), optimized for rice in Sardinia, Italy, applied to several rice genotypes over many years has produced no differences in yields in comparison to what observed using the traditional continuous flooding irrigation method (CF). Because all the previous SP trials have been performed just on one, unpolluted soil, the principal aim of this study is to ascertain the effectiveness of SP to simultaneously minimize the bioaccumulation of As and Cd in rice grain even in soils severely polluted by As and/or Cd. Hence, a Carnise rice genotype was cultivated in an open field in: i) an unpolluted soil; ii) a soil polluted with 55 mg kg-1 of As; iii) a soil polluted with 40 mg kg-1 of Cd; iv) a soil polluted with 50 mg kg-1 of As and 50 mg kg-1 of Cd. In the worst condition of pollution, the amounts of total As and Cd measured in the kernels using a fully validated ICP-MS method is 90 ± 10 µg kg-1 and 50 ± 20 µg kg-1, respectively, i.e. less than 50% and the 25% of the maximum concentration set for these elements in rice by the European Community (200 µg kg-1 for the inorganic As and the total amount of Cd, respectively). SP might represent a simple and valuable tool able to produce safe rice also from soils where the traditional irrigation might produce inedible rice only.

Effects of fertilization and irrigation on vascular plant species richness, functional composition and yield in mountain grasslands.

Land-use intensification is a major threat to biodiversity in agricultural grasslands and fertilization is one of the main drivers. The effects of fertilization on biodiversity and plant functional composition (community-weighted mean traits and mean ecological indicator values) are well studied in lowland regions, but have received less attention in mountain grasslands. Moreover, in inner-alpine dry valleys, fertilizer is often applied in combination with irrigation, and irrigation effects are less well known. We experimentally tested the effects of fertilization and irrigation on vascular plant species richness and the functional composition of mountain grasslands in the Swiss Alps. After five years, fertilization increased yield but the relationship was quadratic with maximum yield reached at intermediate fertilizer levels (58 kg N ha-1year-1). The species richness of all vascular plants and forbs decreased, on average, by 6 and 5 species respectively, per 50 kg N of extra fertilizer (ha-1 year-1) applied. Fertilization also favored fast-growing plants (increased mean specific leaf area) and plants typically found in productive environments (increased mean indicator values for soil productivity and moisture). In contrast, we found no effects of irrigation on plant community composition, which suggests that irrigation does not affect vascular plant diversity to the same extent as fertilization in these mesic mountain hay meadows, at least in the mid-term. Our finding that maximum yield can be achieved at intermediate fertilizer levels is very important from an applied, agronomical and conservation point of view. It suggests that without loss of yield, farming costs and at the same time environmental pollution and negative effects on biodiversity can be reduced by applying less fertilizer. We therefore recommend maintaining non-intensive land use and keeping fertilizer inputs as low as possible to maintain the high plant diversity of mountain grasslands.

[Effects of integration of micro-sprinkler irrigation and nitrogen on growth and development of winter wheat and water and fertilizer use efficiency]. / 微喷灌水氮一体化对冬小麦生长发育和水肥利用效率的影响.

Under the same irrigation amount and nitrogen application rate and after the corn stalks being returned to the field in the wheat-corn crop rotation area, we examined the effects of the integrated water and nitrogen mode of micro-sprinkler irrigation on the growth and development and water and fertilizer use efficiency of winter wheat. In 2016-2018, we conducted a two-year field experiment with six types of micro-sprinkler irrigation water and nitrogen integration modes and seven treatments during the growth period, and investigated the population dynamics, dry matter accumulation transfer during the filling period, and nutrient accumulation during the mature period. There were three modes of irrigation, W1(overwintering water + jointing water + grouting water, 600 m3·hm-2 for each), W2(overwintering water + regreening water + jointing water + grouting water, each for 450 m3·hm-2), and W3(600 m3·hm-2 each for overwintering water and jointing water, and 300 m3·hm-2 each for regreening water and grouting water); two modes of nitrogen application, N1(basic nitrogen application 60% + jointing water nitrogen topdressing 40%) and N2 (basic nitrogen application 60% + jointing water nitrogen topdressing 30% + grouting water nitrogen topdressing 10%); with no fertilization under W1 as control (CK). The results showed that: 1) The amount of overwintering water irrigation increased from 450 m3·hm-2to 600 m3·hm-2, which was beneficial to the total number of both stems and panicles in the overwintering period and consequently to yield. Irrigation in the regreening stage increased the total number of stems at the jointing stage, but with limited effect on the number of panicles. Applying more nitrogen at the jointing stage increased the number of stems per plant, but decreased that of panicles. 2) Four times of irrigation (W2 and W3) during the growth period, combined with nitrogen (N2) in the jointing and filling phases, were conducive to the accumulation of dry matter during the filling period, increasing the number of grains per spike and 1000-grain weight, thereby increasing yield. 3) Compared with the three times of irrigation treatment during the growth period, water consumption and absorption of nitrogen, phosphorus and potassium under the four times of irrigation treatment were increased, and water and fertilizer use efficiency was improved. In W2 and W3 under the treatment of four times irrigation, water consumption of N2 during the growth period was lower than N1, absorption of nitrogen, phosphorus, and potassium were higher than N1, and the irrigation and utilization of nitrogen, phosphorus and potassium were significantly improved, of which W3N2 had the best effect. Therefore, W3N2 treatment (sowing winter wheat after returning corn stalks to the field, irrigating four times during the growth period of micro-sprinkler irrigation, increasing the amount of overwintering water and jointing water irrigation to 600 m3·hm-2, combined with jointing water and filling water topdressing nitrogen fertilizer) increased spike number and 1000-grain weight of wheat andincreased yield, with the highest water and fertilizer use efficiency. It was the best water and nitrogen management mode for the integration of micro-sprinkler irrigation and water and fertilizer for winter wheat in southern Shanxi.

Tuning of the Amount of Se in Rice (Oryza sativa) Grain by Varying the Nature of the Irrigation Method: Development of an ICP-MS Analytical Protocol, Validation and Application to 26 Different Rice Genotypes.

The amount of specific trace elements like selenium (Se) may be of health concern for humans if contained in too high (or low) quantities in staple foods like rice. Among the attempts aimed to optimize the Se concentration in rice, only few studies have been focused on the use of irrigation methods other than continuous flooding. Since intermittent irriguous methods, like sprinkler and saturation, have found to be effective in modifying the bioaccumulation of arsenic and cadmium in rice kernels, the main goal of this study is to measure the amount of the total Se contained in grains of 26 rice genotypes cultivated for two consecutive agrarian vintages in the same open field and with the same water, but differently irrigated with continuous flooding, sprinkler or saturation. To do this, an original and validated ICP-MS method has been developed. The validation parameters accounted for a high sensitivity and accuracy. Sprinkler irrigation is able to reduce in the average of 90% the amount of total Se in kernels in comparison to values measured in rice irrigated with continuous flooding. In conclusion, different irrigation techniques and rice genotypes seem to be valuable tools in order to allow in the future the customized modulation of the Se concentration in rice grain according to the needs of the various populations.

Effect of irrigation on soil health: a case study of the Ikere irrigation project in Oyo State, southwest Nigeria.

Irrigated agriculture is one of the significant contributors to the food security of the millennium development goals (MDGs); however, the modification of soil matrix by irrigation could alter the overall soil health due to changes in soil properties and processes. The objective of the study was to evaluate the effect of irrigation on soil quality status of the Ikere center pivot irrigation project site in Oyo State, southwest Nigeria. Disturbed soil samples were collected from 0 to 30, 30 to 60, and 60 to 90-cm layers from four different sites in three replicates, within the project location for the determination of soil bio-chemical properties. The average values of sodium adsorption ratio (SAR) < 13, electrical conductivity (EC) <4 µS/cm, and pH < 8.5 showed that the soil condition is normal in relation to salinity and sodicity hazards. The effective cation exchange capacity (ECEC), soil organic matter (SOM), total nitrogen (TN), and calcium ion (Ca2+) concentrations were low while the available phosphorus (P) was moderate. The principal component analysis showed EC, ECEC, SAR, SOM, and TN as the minimum data set (MDS) for monitoring and assessing the soil quality status of this irrigation field. In terms of bio-chemical properties, the soil quality index (SQI) of the field was average (about 0.543) while the sampling locations were ranked as site 2 > site 4 > site 3 > site 1 in terms of SQI. The results of this study are designated as baseline for future evaluation of soil quality status of this irrigation field and further studies should incorporate soil physical and more biological properties when considering overall soil quality status.

Temperature profile in apricot tree canopies under the soil and climate conditions of the Romanian Black Sea Coast.

The paper describes the temperature profiles determined by thermal imagery in apricot tree canopies under the semi-arid conditions of the Black Sea Coast in a chernozem of Dobrogea Region, Romania. The study analyzes the thermal vertical profile of apricot orchards for three representative cultivars during summertime. Measurements were done when the soil water content (SWC) was at field capacity (FC) within the rooting depth, after intense sprinkler irrigation applications. Canopy temperature was measured during clear sky days at three heights for both sides of the apricot trees, sunlit (south), and shaded (north). For the SWC studied, i.e., FC, canopy height did not induce a significant difference between the temperature of apricot tree leaves (Tc) and the ambient air temperature (Ta) within the entire vertical tree profile, and temperature measurements by thermal imagery can therefore be taken at any height on the tree crown leaves. Differences between sunlit and shaded sides of the canopy were significant. Because of these differences for Tc-Ta among the apricot tree cultivars studied, lower base lines (LBLs) should be determined for each cultivar separately. The use of thermal imagery technique under the conditions of semi-arid coastal areas with low range of vapor pressure deficit could be useful in irrigation scheduling of apricot trees. The paper discusses the implications of the data obtained in the experiment under the conditions of the coastal area of the Black Sea, Romania, and neighboring countries with similar climate, such as Bulgaria and Turkey.

Agronomic efficiency and grain quality of upland rice cultivars as a function of nitrogen topdressing / Eficiência agronômica e qualidade do grão em cultivares de arroz de terras altas em função do nitrogênio em cobertura

This study aimed to evaluate the agronomic efficiency and grain quality of rice cultivars as a function of nitrogen application in upland conditions with supplemental sprinkler irrigation. The experiment was carried out in 2012/13 at Jaboticabal-SP on a randomized block and split plots design with four replications. The plots were composed of twelve rice cultivars (BRS Aroma, BRS Monarca, BRS Primavera, BRS Sertaneja, BRSMG Curinga, Caiapó, CIRAD 141, Guarani, IAC 165, IAC 201, IAC 202, and IAC 25), and two levels of nitrogen application (0 and 100 kg of N ha-1) in topdress at the R1 stage (panicle differentiation) as subplots. The N application intensifies the degree of lodging, mainly at Caiapó, Guarani, IAC 165, IAC 201 and IAC 25 cultivars. The N application affects the number of sterile spikelets per panicle, mainly in CIRAD 141, BRS Sertaneja, IAC 202, and BRS Aroma cultivars. Caiapó cultivar shows higher grain yield and agronomic efficiency in function of N application, followed by BRS Monarca, BRSMG Curinga, IAC 165, and IAC 202. Although Caiapó, CIRAD 141, Guarani, IAC 165, IAC 202, and IAC 25 cultivars present better results, all the others cultivars also present acceptable values of milling yield, without N application effects. The grain protein content in rice is increased by the N topdressing application.

O objetivo do trabalho foi avaliar a eficiência agronômica e a qualidade do grão em doze cultivares de arroz em função da aplicação de nitrogênio em cobertura no sistema de cultivo em terras altas com uso de irrigação suplementar. O experimento foi conduzido na safra 2012/13 em Jaboticabal-SP, no delineamento experimental de blocos casualizados em parcelas subdivididas, com quatro repetições. Os tratamentos foram constituídos pela combinação de 12 cultivares (BRS Aroma, BRS Monarca, BRS Primavera, BRS Sertaneja, BRSMG Curinga, Caiapó, CIRAD 141, Guarani, IAC 165, IAC 201, IAC 202 e IAC 25) nas parcelas, e duas doses de N em cobertura (0 e 100 kg de N ha-1) nas subparcelas. A aplicação do N em cobertura no ponto algodão (R1) intensificou o grau de acamamento, principalmente nas cultivares Caiapó, Guarani, IAC 165, IAC 201 e IAC 25, de porte mais elevado. A adubação nitrogenada em cobertura interferiu no número de espiguetas estéreis por panícula, em especial nas cultivares CIRAD 141, BRS Sertaneja, IAC 202 e BRS Aroma, respectivamente. A cultivar Caiapó apresentou maior produtividade de grãos e eficiência agronômica em função da aplicação de nitrogênio em cobertura, seguida por BRS Monarca, BRSMG Curinga, IAC 165 e IAC 202. Quanto ao rendimento de engenho mesmo ocorrendo destaque para Caiapó, CIRAD 141, Guarani, IAC 165, IAC 202 e IAC 25, todas as demais cultivares apresentaram valores aceitáveis, sem alterações devido à aplicação de nitrogênio em cobertura. O teor de proteína bruta nos grãos de arroz foi incrementado pela aplicação de nitrogênio em cobertura.

Fertilidade e carbono total e oxidável de Latossolo de Cerrado sob pastagem irrigada e de sequeiro / Soil fertility and oxidizable and total carbon in Oxisol of the Cerrado under pasture irrigated and dryland

A irrigação por aspersão em pastagem pode aumentar a produção de forragem e melhorar as condições químicas do solo. O objetivo deste trabalho foi avaliar a fertilidade e os teores de carbono total e oxidável de Latossolo Vermelho Distrófico de Cerrado em área de pastagem Tifton 85 (Cynodon spp), irrigada e sequeiro. O delineamento experimental foi inteiramente casualizado. Amostras de solo nas camadas de 0-5, 5-10, 10-20 e 20-40cm foram coletadas para avaliação dos teores de Ca, Mg, Al, P, K, Na, H+Al, carbono orgânico total (COT) e determinação de pH. As amostras foram fracionadas quimicamente com dicromato de potássio para a obtenção de frações com diferentes graus de labilidade: F1>F2>F3>F4. A área irrigada apresentou maiores teores de Ca e Mg em relação à área de sequeiro, exceto para o Mg, na profundidade 10-20cm. Foi observada diferença para os teores de COT, sendo os maiores valores verificados na área irrigada, decorrente do maior aporte de biomassa aérea e radicular. Esse padrão também foi constatado para as frações F1 e F2. A irrigação aumenta a concentração de COT, sendo esse aumento mais perceptível nas frações mais lábeis (F1 e F2), e também proporciona a melhoria da fertilidade do solo, aumentando os teores de Ca e Mg.

The sprinkler irrigation on pasture can increase the forage production and improve soil chemical conditions. The aim of this study was to evaluate soil fertility and oxidizable and total carbon contents in Oxisol of the Cerrado under pasture area Tifton 85 (Cynodon spp), irrigated and dryland. The experimental design was completely randomized. Soil samples were collected in the 0-5, 5-10, 10-20 and 20-40cm depth, to evalueted the tenors of Ca, Mg, Al, P, K, Na, H + Al, total organic carbon (TOC) and determined the pH values. The samples were chemically fractionated with potassium dichromate to obtain fractions with different degrees of lability: F1>F2>F3>F4. The irrigated area had the highest Ca and Mg tenors in relation to the no-irrigated area, except for Mg, 10-20cm depth. It was observed difference for the TOC, and the highest values were verified in the irrigated area, due to higher contribution of stem and root biomass at all depths. This pattern was also observed for fractions F1 and F2. The irrigation increases the concentration of TOC, being this increase most noticeable in the more labile fractions (F1 and F2) and also provides improved soil fertility by increasing the concentration of Ca and Mg.

Resposta da cenoura à aplicação de diferentes lâminas de irrigação / Response of the application of carrot different irrigation

A cenoura destaca-se entre os hortícolas que mais se expandiu, porém, como a maioria das hortaliças, seu desenvolvimento é influenciado pelas condições de umidade do solo e mesmo em regiões úmidas a deficiência hídrica é fator limitante da produtividade e qualidade das raízes. Este trabalho teve como objetivo avaliar o efeito de diferentes níveis de água no desenvolvimento vegetativo, produtividade e classificação de raízes de cenoura. O experimento foi conduzido no Campus II do Instituto Luterano de Ensino Superior/Universidade Luterana Brasileira, em Itumbiara ­ GO, no período de abril a agosto de 2003, utilizando a cultivar Brasília. O sistema de irrigação utilizado foi o de aspersão. O manejo da irrigação constituiu-se na aplicação de lâminas de água correspondentes às percentuais da evaporação da água do tanque "Classe A" de 30%, 60%, 90%, 120%, 150% e 180%, aplicadas com turnos de rega de dois e três dias. O delineamento experimental utilizado foi o de blocos casualizados com seis tratamentos e quatro repetições. As parcelas foram constituídas por cinco linhas de plantas espaçadas de 0,20 m, formando uma área de 3 m2 . De cada parcela foram coletadas 10 plantas aos 45, 70 e 110 dias, sendo que na terceira época de coleta foi feita a colheita definitiva em uma área útil de 1,20 m2 por parcela. Avaliou-se a matéria seca da parte aérea, diâmetro, comprimento, peso de raízes e classificação das raízes em classes: extra, primeira, segunda, terceira e refugo. Houve um crescente aumento de matéria seca da parte aérea, diâmetro, comprimento, produtividade da cenoura e melhor classificação, com aumento da lâmina de irrigação, sendo o tratamento 180% da evaporação da água do tanque o que proporcionou o melhor resultado.

The carrot stands out among the vegetables that more expanded, however, like must vegetables, their development is influenced by soil moisture conditions and even in humid regions water deficiency is a limiting factor in productivity and quality of roots. With the objective of evaluating the effect of different irrigation depths, for aspersion, about carrot production, development and classification, a rehearsal was installed in Campus two of the Instituto Luterano de Ensino Superior/Universidade Luterana Brasileira, in Itumbiara ­ GO, in the period of April to August of 2003. The irrigation depths were of 30, 60, 90, 120, 150 and 180% of the evaporation of the "Class A" pan, being applied the levels corresponding to the treatments, on obtained evaporation balance, always in Tuesdays, Thursday and Saturdays.The experimental design was randomized blocks, with five samples. From three coletas 45, 70 e 110 days of the sow, it was evaluated the dry mass of the aerial part, diameter root, length root, productivity (fresch mass of root) and classification. There was growing increase of mass, aerial part, diameter root, length root, of the carrot productivity and classification, with the increase of the irrigation depth, being the treatment of 180% of evaporation of the pan that provided better results