Full Crop Research Articles

The Effects of Every Other Furrow Irrigation Systems on Water Use Efficiency and Yield of Onion at Adami Tulu Agricultural Research Center

Alternate furrow irrigation was believed to improve water use efficiency and labor without a significant tradeoff in yield. It leads to see the effect of alternate furrow irrigation versus every furrow and fixed furrow were evaluated at full crop water requirement. With the objective of to evaluate effect of alternate furrow irrigation with two irrigation intervals (5day and 3day intervals) on crop yield water productivity that might enable to save irrigation water and labor. The experiment has been under taken among AFI, FFI and CFI at Adami Tulu Agricultural Research Center of experimental site for onion production. A field experiment was designed as a two factor factorial experiment (3*2) in RCBD, replicated three times. The two factors were irrigation systems and irrigation interval. Irrigation was applied to furrows using Parshal flume from furrows head ditch with similar inflow rate. Results obtained revealed that alternate furrow irrigation method produced total yield of 25203kg/ha which was not significantly different with that obtained under every furrow irrigation (26469kg/ha). Total yield harvested from fixed furrow irrigation were 24024kg/ha, which showed insignificant difference between the three methods. High marketable yield of 26053kg/ha was recorded from every furrow irrigation and the marketable yield of alternate furrow irrigation were 24601kg/ha which showed insignificant difference between the two method. Water productivity of 7.6kg/m<sup>3</sup>, 7.3kg/m<sup>3</sup> and 5.9kg/m<sup>3</sup> were produced under alternate furrow, fixed furrow and every furrow irrigation respectively. It was found that alternate furrow irrigation method saved 26.61% of water as compared to every furrow irrigation as well as fixed furrow irrigation method saved 26.81% as compared with every furrow irrigation method. Alternate furrow irrigation method with appropriate irrigation interval that is three days of irrigation interval is suitable irrigation method; for semi arid areas where soil is dominated by loam soil and water is liming factor for crop production.

Pre - Extension Demonstration of Alternate Furrow Irrigation for Better Water Management Technologies at Dugda District

The agricultural sector is the main consumer of fresh irrigation water so any effort to improve WUE in this sector gets a lot of attention so, raising WUE through improved of modern irrigation techniques and increasing the capacity of soil output complementary to make better employ of irrigation water and saving water for other uses. The aim of this study was to demonstrate the most effective water-saving techniques and improve the water use efficiency of irrigated onions under limited agricultural water availability for better water management technologies. The treatment consists of conventional furrow irrigation and alternate furrow irrigation method with full crop water requirement in three replications on two farmers. Crop water requirement was estimated using actual daily climatic data. The result showed that conventional furrow irrigation method was the highest bulb yield and yield components when compared to alternate furrow irrigation method. Alternate furrow irrigation method produced total yield of 18.73 t/ha which was not significantly different with that obtained under every furrow irrigation (220.6 Qt/ha). It was also found that yield reduction may be low compared to the benefits gained by diverting the saved water to irrigate extra cultivated land. The result showed that decreasing WP with increased irrigation water from 50% crop water requirement (ETc) from alternate furrow irrigation (5.68 kg m-3) to conventional furrow irrigation 100% Etc (3.6 kg m-3). Increasing water deficit from 100 to 50% ETc led to an increase of onion WP up to 75%. For increasing marketable bulb yield of onion under no water stress scenario, irrigation of onion with conventional furrow irrigation methods could be used. However, under limiting irrigation water resource condition, irrigation of onion could be done with alternate furrow irrigation method to maximize water use efficiency of onion for similar agro-ecology and soil type.

Comparison of conventionally and organically grown pineapple in Sri Lanka: An integrative approach applying life cycle assessment and externalities

The pros and cons of the organic and conventional systems of pineapple cultivation have not been studied extensively. Non-consideration of full crop cycle and non-incorporation of environmental externalities are among the other gaps in research. The present study therefore compared Conventional Cultivation System (CCS) and Organic Cultivation System (OCS) of pineapple grown in Sri Lanka using Life Cycle Assessment (LCA) under five impact categories considering system boundary from gate-to-gate and the full crop cycle. Economic analysis was conducted to determine the best system considering positive and negative externalities. Results showed 87% reduction of Global Warming Potential and 89% reduction of Eutrophication Potential under OCS. Higher toxicity potentials were reported under CCS while OCS resulted in zero toxicity. The net benefit for the farmer under OCS was higher. When the externalities were incorporated, the OCS showed a net gain of USD 8208 per ha while the CCS was no longer beneficial (USD -21,162 per ha). The study proposes economic instruments to incentivise farmers and emphasises the need to minimise adverse impacts of pesticides in sensitive locations. The study also highlights the potential of LCA studies when coupled with monetary values in guiding policy to incentivise farmers towards sustainable pineapple production.

Effect of deficit irrigation and partial rootzone drying on the water consumptive use, growth and yield of faba bean (vicia faba L.) in a gypsiferous soil

Iraq’s farming sector is under increasing pressure to improve water use productivity as a result of the recent drought, environmental concerns regarding sustainable river ecosystems, and government policies on water metering and allocations. To cope with scarce supplies, deficit irrigation, and partial rootzone drying, defined as the application of water below full crop-water requirements, is an important tool to achieve the goal of reducing irrigation water use. It is necessary to develop new irrigation scheduling approaches, not necessarily based on full crop water requirement, but ones designed to ensure the optimal use of allocated water. These two methods of irrigation are one way of maximizing water use efficiency (WUE) for higher yields per unit of irrigation water applied: the crop is exposed to a certain level of water stress either during a particular period or throughout the whole growing season. The expectation is that any yield reduction will be insignificant compared with the benefits gained through diverting the saved water to irrigate other crops. This paper reviews the yield response of the faba bean (Vicia faba L.). The deficit of irrigation on gypsiferous soils is not known. A field experiment was carried out to study the effect of deficit irrigation and partial drying of the root system on the growth and yield of the bean Randomized Complete Blocks (RCBD) design in gypsiferous soil in the fields of the College of Agriculture- Tikrit University, which is located on Latitude 49° 40ʹ 34˝ North and Longitude 40° 38ʹ 43˝ East At an altitude of 129 m above sea level. The study included seven treatments of full irrigation, deficit irrigation, 25, 50 %, and fixed, alternating partial drying. The seeds of the Barcelona variety were sown for the season on 16/10/2021 and harvested on 2/4/2022. The results showed that the full irrigation treatment gave the highest water consumption use of 635 mm, while the alternative partial root drying decreasing 50% gave the lowest water consumption use of 245 mm and gave the highest crop water use efficiency of 2.0 kg m-3. Treatment full irrigation gave the highest seed yield of 5186.3 kg.ha-1, While the 50% deficit irrigation treatment gave the highest dry weight of the root system, which was 25.6 gm.plant-1.

Why no-till system sequesters more carbon and is more resilient and productive with contrasting fertilization regimes in a highly weathered soil?

Land management systems that comprise the principles of conservation agriculture (CA) can lead to soil organic carbon (SOC) gains over time. Nonetheless, how fertilization regimes interfere with their performance in highly weathered soils is still uncertain. This study presents results on SOC storage, crop yield, and soil resilience from a long-term experiment in southern Brazil (Ponta Grossa – Paraná State) 26 years after its establishment in 1989 combining a gradient of soil disturbance through diverse soil management strategies with contrasting fertilization regimes. We hypothesized that preserving soil structure rebuilt over time through no-till system plays a significant role in SOC persistence and the fertilization regime can impact land management performance on soil resilience and crop yield. The experimental design was laid out as a split plot through completely randomized blocks. The main plots comprised the treatments related to soil management systems: 1) conventional plow-based tillage – CT; 2) minimum tillage (Chiselling replacing plowing) – MT; 3) no-till with one chisel plowing every three years – NTch; and 4) continuous no-till system – NTS. The sub-plots comprised full crop fertilization (FCF) for all crops and low crop fertilization (LCF) by suppressing K and P fertilization and maintaining N in broadcast application. SOC stocks significantly improved as the soil disturbance diminished, resulting in higher soil resilience indexes for NTS and NTch. Differences in SOC stocks between the contrasting treatments NTS and CT were higher under low fertilization, resulting in C and N sequestration rates of 1.14 and 0.14 Mg ha−1 year−1 under LCF compared to 0.77 and 0.08 Mg ha−1 yr−1 in FCF at the 0–100 cm layer. Such higher differences were induced by overall higher SOC stocks of CT when under FCF and higher SOC stocks in subsoil depths promoted by NTS when under LCF. High fertilization treatments produced cumulative yields 1.5 times higher for soybeans and 2.5 times higher for corn throughout the 26 years of the experiment. Labile C fractions extracted by hot water (HWEOC) and K-permanganate (POXC) were systematically increased as the disturbance diminished. Gains in labile fractions were promoted in deeper layers in lower disturbance treatments (NTch and NTS). We conclude that combining conservation agriculture principles ultimately defined the potential for SOC sequestration. The high soil resilience under the NTS in this research indicates a considerable potential to reverse the soil degradation and decline of the SOC and labile fractions by conversion to intensive NTS (high and diversified annual C input) associated with absence of soil disturbance.

Increasing cattle slurry application to grass-clover leys of different ages did not affect nitrate leaching but increased legacy effect in mixed organic crop rotations

ContextOrganic dairy farms with grass-clover often have a large N surplus, due to biological N fixation and in addition, manure application, which challenges the efforts to reduce N losses. Potential loss pathways include leaching from grass-clover ley and subsequent crops, but if managed appropriately this N legacy effect may result in higher yields in the subsequent crops. ObjectiveTo investigate the fate of the ley phase N surplus including losses of nitrate in grass-clover leys, contribution to the N supply of the subsequent crop, and the contribution from the long-term slurry N application to grass-clover leys to nitrate leaching and yields in subsequent crops. MethodsWe quantified nitrate leaching across three years in two six-year crop rotations with two or four years of grass-clover ley and examined legacy effect of the grass-clover ley in relation to short- or long-term N fertilization levels. This was done by measuring water nitrate contents below the root zone combined with water balance modelling. ResultsNitrate leaching in 1- to 4-yr-old grass-clover leys were not influenced by cattle slurry application of up to 300 kg total-N ha-1 (equivalent to approximately 170 kg available N). Leaching losses were 2 - 19 kg N ha-1 yr-1 across grassland ages and application rates. Arable crops showed correspondingly low nitrate leaching (4–24 kg N ha-1 yr-1) except for barley/peas (74 kg N ha-1 yr-1), where a catch crop was established after autumn mechanical weed control. The legacy effect of fertilization on N yield was found in the first year following cultivation of 2-yr-old grass-clover swards and in both year one and two following cultivation of 4-yr-old grass-clover swards. The legacy effect was generally better predicted by the long-term cumulated fertilizer N application during the last rotation (six years) as compared to the most recent grass-clover N application rate. Nitrate leaching in the arable phase of the mixed crop rotations was not affected by fertilizer application in the ley phase. However, this might depend on catch crop strategy in the arable crops. ConclusionsNitrate leaching in dairy crop rotations was not influenced by cattle slurry application. It was found that both the short- and long-term slurry application history were able to explain the legacy effect and of those, the long-term was the best predictor. ImplicationsThe study shows that N leaching reduction targets can be met in an organic dairy crop rotation when attention is paid to the full crop rotation and utilization of short- and long-term legacy effects of slurry application.

Effects of cold stress on physiologic metabolism in the initial phase and performance of broiler rearing

This study aimed to investigate the effects of 8 h of cold stress (18 °C) every day in broiler chicks during the first 7 days of rearing on crop filling analysis, yolk sac consumption, digestive and immune organs weights, and physiological metabolism at seven days and performance between 1 and 35 days. Cobb500 male broiler chickens (n = 274) were randomly assigned to two treatments. The treatments consisted of varying environmental temperatures during the first week post-housing. Chicks were reared at a thermoneutral temperature (32 °C) or under cold stress (18 °C) for 8 h/day during the first week, and both groups were subsequently reared at a thermoneutral temperature for 8–35 days. The thermoneutral group reached 90% full crop after 48 h of housing (P < 0.05), while the cold-stressed group had more empty crops at 2 h and 48 h after housing (P < 0.05). The chick cloacal temperature was not affected by the treatments (P > 0.05). Additionally, the treatment did not affect serum amylase and corticosterone levels, feed intake, body weight gain, or feed conversion ratio (P > 0.05, while the cold-stressed group had elevated heterophil/lymphocyte count at day 7 (P < 0.05). The thermoneutral group showed higher viability (%) at 7 and 35 days and a higher production factor at 35 days (P < 0.05). Broiler chickens under cyclic cold stress experienced decreased yolk sac absorption during the first week and increased feed intake and feed conversion ratio after 35 days of rearing. Viability was also lower in the cold-stressed group. An appropriate strategy to minimize these adverse effects is to rear the chicks in a thermoneutral environment during the first week.

Effects of Cluster Farming and Crop Technology Dissemination on the Livelihoods of Farmers: The Case Chobi District West Shewa Zone of Oromia, Ethiopia

Enhancing productivity among smallholder farmers is widely perceived as a key strategy that is achieved through promoting an agricultural cluster farming approach. The adoption of improved agricultural production technologies is central to increasing production and productivity. This study was conducted in the Chobi district of the West Shewa zone with the objectives of this study to introduce improved crop technologies and to enhance crop productivity. In the Chobi district, six types of crop technologies were promoted in the 2019/20 production season. The district is a previously unaddressed area in improved crop production technology and a total of 234 farmers (197 male and 37 female) benefited with a total of 68.97 quintals disseminated improved seed. In the information-sharing field days held a total of 499 stakeholders participated. From the 13 improved varieties that cover 164.3 hectares of land, a total output of 3753 quintals of grain was harvested. The yield effect of different crop varieties in the Chobi district scores higher yield in barley 32 Qt/ha and maize 80 Qt/ha than the national and regional average. The yield from linseed is 11 Qt/ha higher than the national average and the productivity of potato 120 Qt/ha is higher than the regional mean yield. Therefore, the study recommends a cluster farming with a full crop production package is crucial to enhance the income gains of smallholder farmers and the concerned stakeholders have to engage in the dissemination of climate-smart and resilient crop production technologies and extension services.

Effects and Interactions of Incubation Time and Preplacement Holding Time on Mortality at Placement, Yolk Sac Utilization, Early Feeding Behavior and Broiler Live Performance.

The effects and interactions of incubation time and chick preplacement holding time on mortality at placement, utilization of yolk sac, crop filling rate, early feeding-drinking behavior, and broiler live performance were investigated. Ross 308 broiler hatching eggs from a 39-week-old flock were set in two identical setters in a commercial hatchery, with the setting time 12 h earlier in one machine. At the end of incubation, chicks were removed from the hatchers at the same time. Thus, the incubation times were either 504 h (normal incubation time (NIT) treatment) or 516 h (longer incubation time (LIT) treatment). After the pull time, chicks from each incubation time group were subjected to either 6, 24, 48, 60, or 72 h preplacement holding times. At placement, chicks were given access to feed and water. In total, 19,200 chicks were randomly assigned to a total of 10 subtreatment groups (2 incubation times × 5 preplacement holding times). Therefore, a total of 1920 chicks were used in each subtreatment group for the grow-out period in a commercial broiler house. For the first week of the experiment, 160 randomly selected as-hatched (not sexed) chicks were placed in 12 replicate floor pens (120 total pens). From the second week of age onward, chicks from two pens were combined into six replicate pens, with 320 chicks per replicate (60 total pens). An interaction was found between incubation time and preplacement holding time for residual yolk sac (RYS) weight (g, %) (p < 0.001). RYS weight was greater at pull time and at 6 and 24 h of preplacement holding in the NIT treatment compared to the LIT treatment, while differences were no longer evident at 48-72 h. The lowest percentage of chicks with full crops and eating activity was observed in the shortest preplacement holding time (6 h) group at 3 h after placement. As expected, the initial BW at placement clearly decreased with increasing duration after the pull time (p < 0.05), with the highest and lowest weights found in the 6 and 72 h holding time treatments, respectively. This BW difference was still evident at 35 d after placement and chicks held for the longest period after the pull time (72 h) showed the lowest BW (p < 0.001). However, there was no significant difference between the 6 and 60 h preplacement holding times. Mortality during the first 7 d after placement increased only when the preplacement holding time was extended to 72 h (p = 0.031). Similarly to the 7 d results, chicks held for 72 h exhibited higher 0-35 day mortality compared to those held for 6 or 24 h (p = 0.028). Neither BW nor mortality was affected by incubation time treatment at 35 d after placement (p > 0.05). It can be concluded that there were no significant differences in average BW and mortality, up to and including a 60 h holding time under thermal comfort conditions, but a 72 h preplacement holding time resulted in final BW and mortality being negatively affected. In addition, LIT tended to have a beneficial effect on BW and mortality compared to NIT when the preplacement holding time was shorter (6-24 h) but had a negative effect for extended holding times (48-72 h).

In Vitro Antagonistic Activity of Entomopathogenic Fungi Against Phytophthora infestans

Potato downy mildew is a disease caused by a fungus called Phytophthora infestans (Mont.) de Bary, which is mainly seen in potatoes and tomatoes, but also in other culture and wild plants belonging to the Solanaceae family. This fungus is quite important both from an economic and historical point of view. In case of an epidemic, it can cause full crop deterioration or serious losses in potatoes. Although cultural and chemical control methods are generally used in the control of the disease, there is no specific biological control method in this regard. Entomopathogenic fungi (EPFs) are generally used as biological control agents in the control of insect pests. Recently, there are many studies showed that these fungi can live endophytically on various cultivated plants and provide beneficial properties to the plants they live with. In this study, it was aimed to determine the in vitro antagonistic activities of different entomopathogenic fungi previously isolated from potato fields and identified by molecular methods against P. infestans. Earlier work determined that these fungi had a lethal effect on Leptinotarsa decemlineata (Say, 1824). Antagonistic activity tests were performed according to the "direct opposition method" and percentage (%) activity values were calculated. As a result of the tests, the most effective isolates were found to be Beauveria sp. SK-14 (75.23%) and Metarhizium sp. SK-24 (76.23%). It is thought that the results obtained will contribute to the biocontrol of diseases and pests in potatoes.

Changes in energy balance and total evaporation with age, and between two commercial forestry species in South Africa

Expansion of the area planted to eucalypts has been observed in the last two decades due to an improvement in markets for products from this tree species. This has raised concerns over the management of freshwater resources as other species are replaced by Eucalyptus, which has been shown to use more water than other commercial forestry species. The energy balance (EB) and total evaporation (ET) over Acacia mearnsii was previously monitored at the Two Streams research catchment, and the site harvested in 2018 with subsequent re-planting of E. dunnii. This presented an opportunity to measure the two-year-old E. dunnii (Edun2) EB and ET for comparison on the same site with the previously planted A. mearnsii with results from two-year-old A. mearnsii (Amear2) and six-year-old A. mearnsii (Amear6) crops. ET and EB measurements on Amear2 were obtained using a large aperture scintillometer, while eddy covariance was used for Amear6 and Edun2. Measurements were conducted in October 2007 to September 2008, October 2012 to September 2013 and October 2019 to September 2020 for Amear2, Amear6 and Edun2. The leaf area index (LAI) was measured using a LAI 2200 plant canopy analyser for all crops. The annual plantation water productivity (PWPWOOD) was calculated as a ratio of productive stand volume to ET for Amear2, Amear6 and Edun2. Results showed that latent energy fluxes dominated the EB in all crops for both summer and winter seasons, indicating a possibility that trees were not limited by plant available water in winter (dry season). The Edun2 and Amear2 annual ET was statistically (p > 0.05) similar, while ET of the younger crops (Amear2 and Edun2) was 12% greater than Amear6. High ET in Edun2 was caused by high LAI while Amear2 was caused by high transpiration per unit leaf area in young trees than in mature trees. Monthly crop factors were derived from FAO ETo and ET for all three crops, providing a convenient and transferable method of estimating ET from meteorological data over a large scale. The Edun2 PWPWOOD was greater than Amear2, while Amear6 was greater than both the young crops. This study provides insight into the total water-use by different species at different stages of growth at the same site. It is recommended that catchment water balance measurements be continued on the current E. dunnii crop for the full crop rotation to assess the long-term impact of E. dunnii on streamflow.

Functional Quality and Radical Scavenging Activity of Selected Watermelon (Citrullus lanatus (Thunb.) Mansfeld) Genotypes as Affected by Early and Full Cropping Seasons.

Growing conditions and seasonal fluctuations are critical factors affecting fruit and vegetable nutritional quality. The effects of two partially overlapping cropping seasons, early (ECS; January-May) and full (FCS; March-July), on the main carpometric traits and bioactive components of different watermelon fruits were investigated in the open field. Four watermelon genotypes, comprising of three commercial cultivars 'Crimson Sweet', 'Dumara', 'Giza', and the novel hybrid 'P503 F1', were compared. The carpometric traits varied significantly between genotypes. Soluble solids and yield were higher under FCS than ECS. The variation affecting colour indexes between the two growing seasons exhibited a genotype-dependent trend. The antioxidant components and radical scavenging activity of watermelon fruits were also significantly affected by differences in received solar energy and temperature fluctuations during the trial period. The average citrulline, total phenolics and flavonoid contents were 93%, 71% and 40% higher in FCS than in ECS. A genotype-dependent variation trend was also observed for lycopene and total vitamin C between cropping seasons. The hydrophilic and lipophilic radical scavenging activities of the pulp of ripe watermelon fruits of the different genotypes investigated varied between 243.16 and 425.31 µmol Trolox Equivalent (TE) of 100 g-1 of fresh weight (fw) and from 232.71 to 341.67 µmol TE of 100 g-1 fw in FCS and ECS, respectively. Our results, although preliminary, show that the functional quality of watermelon fruits is drastically altered depending on the environmental conditions that characterize the ECS and LCS.

Modification of Cv. Merlot Berry Composition and Wine Sensory Characteristics by Different Leaf Area to Fruit Ratios

This study aimed to evaluate the effects of cluster thinning and severe shoot trimming on berry and wine composition and wine sensory characteristics of Merlot variety, in the context of climate change challenges related to grapevine ripening and the corresponding high alcohol content in wine. In two seasons, two different crop sizes were obtained via cluster thinning and combined in a two-factorial design with severe shoot trimming (SST) and its respective high canopy control (HC). In both seasons, cluster thinning (CT) resulted in higher Brix in grape juice and higher alcohol in wine than full crop size (FC), whereas SST obtained lower values than HC. Total anthocyanins and phenolics in wine were increased by CT, whereas SST had no any significant effect on wine’s phenolic content. Several sensory characteristics of wine were positively affected by CT in both seasons, including aroma intensity, wine body and overall wine quality, whereas SST wines were in one season characterized by increased perception of vegetal aroma, acidity and bitterness, and decreased perception of body, persistency and taste balance. Our results demonstrate that practices which affect the leaf area to fruit ratio have a major impact on wine sensorial characteristics, concluding that their choice should be based on the desired wine style.

Predicting Long-Term Effects of Alternative Management Practices in Conventional and Organic Agricultural Systems on Soil Carbon Stocks Using the DayCent Model

Recently, many countries have introduced policies that promote sustainable agricultural practices, such as reducing synthetic nitrogen fertiliser and promoting diversified crop rotation. While such management changes might represent an opportunity for the agricultural sector to mitigate the impacts of climate change through carbon (C) sequestration in soils, there are still uncertainties due to the scarcity of reliable long-term data to prove this assumption. In this study, we applied the DayCent model using empirical data from a farm-scale study and an experimental trial study at Nafferton farm in the UK, to assess the long-term effects of contrasting agricultural systems (conventional vs. organic), grazing regimes (non-grazed vs. grazed), arable systems with ley phases, mineral vs. compost fertility sources and conventional vs. organic crop rotation on soil C stocks (0–0.20 m depth). The simulations showed that grazing and higher ley time proportions can increase soil C stocks for a period of at least 30 years, regardless of the agricultural system used (average increase in rates of 0.25 ± 0.02 Mg ha−1 yr−1). Compost fertiliser promoted soil C accumulation for the same period (average increase in rates of 0.3 Mg ha−1 yr−1), but its magnitude was dependent on the choice of crops in the rotation. However, ley time proportions higher than 40% of the full crop rotation did not improve soil C accumulation further. We conclude that the DayCent model can be used to identify the quantity of and the effective period for which management practices can be used to target mitigation efforts, but the balance between sustainability and productivity aspects warrants further research.

Energy Crisis—Alternative Use of Winter Bread Wheat Grain Depending on Protein Content

Our economic analysis aimed to evaluate the profitability of winter bread wheat production based on two fundamental aspects. The first was the grainprotein content as a criterion for determining grain prices. The other was a comparative simulation of production profitability relying on grain production costs in 2015 and 2022. We used the results of a field experiment conducted in 2014 and 2015 involving winter bread wheat fertilised with nitrogen applied at progressive increments of 40 kg N ha−1 within arange from 0 to 240 N ha−1 with or without fungicide protection. We assumed that experimental factors significantly affected both the yield and the market value of grain, and hence the profitability conditioned by wheat prices on global markets. The working hypothesis of this paper is: wheat production profitability has not changed in the face of a global energy crisis. Our analysis shows that growing bread wheat generates profit when inputs are high: these inputs include high nitrogen rates and full crop protection. The real grain selling price guarantees production profitability. We should consider that, in the circumstances of a global energy crisis, the world should possibly switch to baking products from low-protein flour. Only upon such an assumption can the expenditure on fertilisers and fungicides be significantly reduced.

Guayule growth and yield responses to deficit irrigation strategies in the U.S. desert

Deficit irrigation can maximize the water productivity (WP) of guayule and increase the percent rubber (%R) in shrubs compared to irrigation meeting full crop evapotranspiration (ETc). In this study, we hypothesize that certain deficit irrigation strategies that impose soil water deficits during specific periods of growth or throughout the growing season might produce higher %R and equivalent rubber yield (RY), thereby, increasing WP compared to full irrigation. Herein, growth and yield responses of direct-seeded guayule to different water deficit schemes were evaluated in an experiment on a silty clay loam soil, in a field in central Arizona using furrow irrigation. Two guayule cultivars (AZ2 and AZ6) were grown for 22.5 months (Apr. 2020-Mar. 2022) in a split-plot design, with six irrigation treatments in whole plots and cultivars in split-plots. After homogeneous irrigation for two months, irrigation treatments were begun. A control treatment was irrigated to meet full ETc. The other five treatments were irrigated with less water using various deficit irrigation strategies imposed during the two-year growing period. Measurements included plant height (h), cover fraction (fc), soil water contents, harvest of dry biomass (DB), RY, resin yield (ReY), %R, and percent resin (%Re). Total water applied (TWA) by irrigation and precipitation to treatments varied from 2780 to 1084 mm and DB varied from 20.5 to 9.1 Mg ha−1. The h and fc were significantly greater at higher irrigation levels, while they were also significantly greater in AZ6 than AZ2. The DB, RY, and ReY generally increased linearly with TWA. However, it was found that a treatment applying every other irrigation of the control resulted in statistically equivalent yields to the control, with 36% less irrigation. The %R generally decreased with TWA, while %Re did not change. However, DB, %R, and %Re were significantly greater for AZ2 than AZ6, as were RY, ReY, and WP. Among the deficit treatments evaluated, every other irrigation offers the best strategy to significantly increase guayule WP without causing a yield penalty.

Integrated weed management with strategic tillage can maintain soil quality in continuous living cover systems

Maximizing living cover and minimizing soil disturbance with no-till are key strategies in regenerative row-crop production. Although living cover and no-till can increase beneficial soil carbon and water stable aggregates (WSA), annual crops in rotation with perennials often rely on herbicides to control weeds and terminate perennials. Integrated weed management (IWM) reduces reliance on herbicides by employing multiple weed control strategies including tillage and/or cultivation. However, many no-till growers are reluctant to implement some soil disturbance due to concerns about negative impacts on soil health. For that reason, we hypothesized that compared to continuous no-till and standard herbicides (NT-SH), a strategic inversion tillage in IWM (ST-IWM) would result in lower soil carbon and WSA in the year following the tillage event. We also hypothesized that soil carbon and WSA would not differ between the two systems when sampled after cover cropping and 2 years of perennials. We tested these hypotheses within a 6-year, diverse, dairy crop rotation initiated in 2010 in central Pennsylvania in a channery silt loam soil. The systems were compared in split-plots in a full crop entry experiment, where the six phases of the crop rotation were planted every year in a randomized complete block design, replicated four times. We compared the soil health indicators in spring 2010 prior to the start of the experiment and in 2013 and 2019 following inversion tillage (ST-IWM) or herbicide termination (NT-SH) of the perennial forage in the first year of the rotation. We also compared these indicators in the sixth year of the rotation after 3 years of annual and cover crops and 2 years of perennial forage. We sampled at two depths: 0–5 and 5–15 cm for total carbon and bulk density, 0–5 cm for labile carbon and 0–15 cm for WSA. Results indicate that despite initial smaller soil health values in the ST-IWM system following inversion tillage, all properties except labile carbon were similar to the NT-SH system in the sixth year of the rotation.

Effect of Rates and Sources of N Fertilizer Application on Dynamics of Rice Brown Leaf Spot Disease (Bipolaris oryzae) Incidences in the Dry Zone of Sri Lanka

Nitrogen inputs; sources or application amounts are key determinants of yield determination and determination of resistance or sensitivity to pathogen activities. This study aimed at assessing the impact of source and rate of application of N fertilizers on Rice Brown Leaf Spot (RBLS) disease incidences and dynamics in lowland irrigated rice crops. Leaf N using relative leaf chlorophyll content, leaf N concentration and crop yield were assessed during the wet 2018/19, 2019/20 and 2020/21 seasons and dry 2019 and 2020 seasons in the field research facility of Rajarata University of Sri Lanka. The conventional systems (The Department of Agriculture recommended inorganic fertilizer application at 100% N), integrated system (50% N with conventional through inorganic fertilizer and 25% N with organic manure mixture), and organic system (50% of N conventional through organic manure) were tested using a new improved rice variety Bg300, using a randomized complete block design with six replicates. Wet and dry seasons were contrastingly different in disease prevalence, where critical levels of incidences were visible earlier in the wet season compared to the dry season. Initial stages of the study, organic systems resulted in higher disease incidences, thus reaching infections of the full crop before conventional and integrated. Several seasons of continuous organic manure incorporation enhanced the resistance of organic systems to RBLS disease compared to the rest. The leaf N concentrations were higher in conventional, thus the RBLS incidences were relatively low, due to negative correlations between disease incidences. Rice yields also resulted in a significant negative correlation with disease incidences and were diminished in integrated and organic systems later. The yield suppression due to diseases such as RBLS in organic transition can be overcome by using an integrated approach and building a balanced substitutable nutrient management strategy.

Bayesian multi-level calibration of a process-based maize phenology model

Plant phenology models are important components in process-based crop models, which are used to assess the impact of climate change on food production. For reliable model predictions, parameters in phenology models have to be accurately known. They are usually estimated by calibrating the model to observations. However, at regional scales in which different cultivars of a crop species may be grown, not accounting for inherent differences in phenological development between cultivars in the model and the presence of model deficits lead to inaccurate parameter estimates. To account for inherent differences between cultivars and to identify model deficits, we used a Bayesian multi-level approach to calibrate a phenology model (SPASS) to observations of silage maize grown across Germany between 2009 and 2017. We evaluated four multi-level models of increasing complexity, where we accounted for different combinations of ecological, weather, and year effects, as well as the hierarchical classification of cultivars nested within ripening groups of the maize species. We compared the calibration quality from this approach to the commonly used pooled approach in which none of these factors are considered. The pooled model led to over-confident process model parameter estimates and comparatively poor calibration quality. The mean value of the unexplained residual error standard deviation reduced from 5.5 BBCH (phenological development units) in the pooled model case (BM-0) to 5.3 BBCH when eco-region and year effects (BMM-1) were considered. Additionally accounting for weather effects (BMM-2a) resulted in a mean value of 5.2 BBCH. Calibration quality especially improved when the hierarchical classification of cultivars within ripening groups of maize was incorporated. Including the hierarchical classification with eco-region and year effects (BMM-2b) led to a mean residual error of 4.4 BBCH while additionally considering weather effects in the full model case (BMM-3) resulted in a value of 4.3 BBCH. Our findings have implications for regional model calibration and data-gathering studies, since it emphasizes that ripening group and cultivar information is essential. Furthermore, we found that if this information is not available, at least weather, eco-region and year effects should be taken into account. Accounting for only the eco-region and year effects led to parameter-compensation of the missing weather effects. Our results can facilitate model improvement studies since we identified possible model limitations related to temperature effects in the reproductive (post-flowering) phase and to soil-moisture. We demonstrate that Bayesian multi-level calibration of a phenology model facilitates the incorporation of hierarchical dependencies and the identification of model limitations. Our approach can be extended to full crop models at different spatial scales.

Evapotranspiration Based Irrigation Trials Examine Water Requirement, Nitrogen Use, and Yield of Romaine Lettuce in the Salinas Valley

Cool season vegetables require adequate soil moisture to assure that maximum yield and quality are achieved. On California’s central coast, where the majority of cool season vegetables are produced in the US, long-term overpumping of irrigation water has reduced groundwater levels and led to environmental degradation. Two evapotranspiration (ET) based irrigation field trials were performed near Salinas CA (USA) to determine if ET-based irrigation scheduling could conserve water while producing romaine lettuce (cv. Sun Valley) of commercially viable yield. Sprinklers were used for seed germination and crop establishment. Four drip irrigation treatments were then imposed using a randomized complete block design with six replications. The CropManage decision-support model was used to estimate the full (100%) crop water requirement based mainly on ET replacement. Other treatments included 50% 75% and 150% of the full water requirement. The 100% treatment received 185 mm of water in 2015 and 247 mm in 2016, both of which were well below prior guidance and grower reports. Yields from the 100% and 150% treatments were not significantly different and were similar to industry average, while yields were significantly lower for the 50% and 75% treatments. The 100% treatment had the highest water use efficiency, and the 100% and 150% treatments together had the highest nitrogen recovery efficiency. Irrigation of romaine near the 100% ET replacement level can potentially reduce environmental impacts associated with nitrate leaching and surface runoff.