Marketable Fresh Yield Research Articles

Effect of different bio-fertilizers on growth and yield of spinach (Spinacia oleracea L.)

A field trial was conducted with the aim to study the effect of different bio-fertilizers on growth and yield of spinach (Spinacia oleracea L.) Spinach stands as a significant leafy vegetable in global agriculture, prized for its nutritional richness and versatile culinary applications. With an increasing emphasis on sustainable agricultural practices, the investigation of alternative fertilization methods has garnered attention, particularly bio-fertilizers known for their eco-friendly attributes and potential multifaceted benefits. This study delves into the effects of diverse biofertilizers on the growth and yield of spinach crops. During the rabi season of 2023-2024, the field experiment was carried out at AlOA Amity University Noida U.P. Agricultural Research Farm. The experiment was organized in a randomized complete block design to assess the efficacy of different bio-fertilizer treatments. Key growth parameters including plant height, leaf area were meticulously monitored throughout the crop cycle. Additionally, yield metrics such as fresh weight and marketable yield were recorded to evaluate the productivity of spinach plants under various bio-fertilizer regimes with six treatments consisting of a single or combination of bio-fertilizers in three replications. T6 (Vermicompost + azotobacter +poultry manure) exhibited the highest values for maximum plant height, no. of leaves per plant, length and width of leaves, leaf area, followed by T5 and T4 at 30, 45, and 60 DAS. The minimum plant height and other morphological parameters were observed in the treatment T1 (control) at 30, 45, and 60 DAT. T6 (Vermicompost + azotobacter + poultry manure), T5 (Azotobacter + Vermicompost), and T4 (FYM and poultry manure) had the highest fresh weight whereas the control treatment had the lowest. When compared to all other treatments, the treatment T6 (Vermicompost + Azotobacter + poultry manure) produced the highest growth and yield.

Effects of Plant-Derived Protein Hydrolysates on Yield, Quality, and Nitrogen Use Efficiency of Greenhouse Grown Lettuce and Tomato

Plant-derived protein hydrolysates (PHs) are gaining global interest for their sustainability and positive effects on crops under abiotic stresses. However, the long-term effects of PHs on the yield and quality of greenhouse crops have not been described. Romaine lettuce (Lactuca sativa L.) and Micro-Tom tomato (Solanum lycopersicum L.) were grown with commercial growing media in 1 L pots and fertigated with four N levels (2, 5, 10, and 15 mM). PH (0 or 3 g/L) was applied as a foliar spray (PH-F) or root drench (PH-R) once every week. Compared to PH-F, PH-R effectively stimulated the yield, photosynthesis, water-use efficiency, chlorophyll contents, and antioxidant activities, and compounds regardless of N levels and species. Increasing the N level led to a total dry weight gain, and PH-R enhanced the lettuce shoot dry weight (+31%) and tomato fruit dry weight (+22%). PH-R also increased the fresh marketable yield of lettuce (+21%) and tomato (+32%). The increasing N level decreased antioxidant parameters in lettuce leaves, not in tomato fruits, whereas PH-R improved them in both species. PH-R significantly enhanced the N use and uptake efficiency. Taken together, our results suggested that the addition of PH-R effectively increased the N uptake and subsequently increased the lettuce and tomato yield and quality regardless of N levels.

Optimizing Use of DMI Fungicides for Management of Apple Powdery Mildew Caused by Podosphaera leucotricha in New York State.

Powdery mildew, caused by the ascomycete Podosphaera leucotricha, is an endemic disease found wherever apples are grown that reduces both tree vigor and fresh market yield. In the absence of durable host resistance, chemical management is the primary means of disease control. Demethylation inhibitor (DMI) fungicides are widely used to manage apple powdery mildew, but members within this fungicide class have been observed to differ in efficacy with respect to disease control. Moreover, debate exists as to the optimal timing of DMI fungicide applications for management of apple powdery mildew. In this regard, the goal of this study was to determine the best-use practices for DMI fungicides to manage apple powdery mildew in New York State. Multiyear trials were conducted to evaluate the potential differential efficacy performance of four common DMI fungicides, and additional trials were conducted to assess optimal application timing. In all years, we observed that treatments of flutriafol and myclobutanil consistently had the lowest incidences of powdery mildew compared with difenoconazole and fenbuconazole. In the 2018 and 2021 trials, the newly registered mefentrifluconazole was more comparable to the difenoconazole program with respect to powdery mildew disease incidence. We hypothesize that differences in DMI efficacy may result from each fungicide's water solubility and lipophilicity characteristics and thus their ability to move systemically in the host or more easily penetrate the surface of germinating conidia. Applications timed between petal fall and first cover resulted in the lowest incidence of powdery mildew on terminal leaves of apple shoots compared with applications timed before petal fall. These observations are contrary to previous studies conducted in regions with differing climates. We also found that the incidence of secondary powdery mildew observed 2 weeks after petal fall was influenced by applications of DMI fungicides during the previous season. For example, management programs consisting of applications of flutriafol or myclobutanil in the previous season tended to have lower incidence of apple powdery in the next spring, presumably because of reductions in overwintering inoculum. Despite reports of DMI resistance in other apple pathosystems, the DMI fungicide class is still relevant for the successful management of apple powdery mildew in New York State.

Innovative Living Mulch Management Strategies for Organic Conservation Field Vegetables: Evaluation of Continuous Mowing, Flaming, and Tillage Performances

Organic vegetable production is particularly affected by weed pressure and mechanical weeding is the major tactic implemented by growers to keep weeds under economic thresholds. Living mulch (LM) has been shown to provide several environmental services; however, LM management is required to avoid competition between service crops and cash crops. The aim of this trial was to evaluate two innovative LM-based management systems: a system that provided LM growth regulation by means of flaming (LM-FL) and a system where the LM was regularly mowed by an autonomous mower (LM-AM), both compared with a control without LM and based on standard tillage operations (TILL). The three management systems were evaluated in terms of crop production, weed control, and energy consumption on a 2 yr organic crop rotation of cauliflower (Brassica oleracea L. var botrytis) and eggplant (Solanum melongena L.). LM-AM produced an acceptable fresh marketable yield for both vegetable crops. Moreover, the weed dry biomass obtained in LM-AM-managed plots was lower compared to the LM-FL plots and ranged approximately from 200 to 300 kg ha−1. Furthermore, LM-AM management resulted in lower energy consumption (−2330 kWh ha−1 with respect to the TILL system and −7225 kWh ha−1 with respect to the LM-FL system). The results of this trial suggest that autonomous mowers have a great potential to improve LM management and help with implementing sustainable organic vegetable systems.

Cassava yield indicators and total organic carbon in tropical soils under different fertilization treatments

Cassava is a crop of major socioeconomic importance in Brazil because of its versatility and high yield in nutrient-poor soils. Fertilization can improve soil quality and further increase cassava yield. This study aimed to investigate the effects of different fertilizer sources on soil total organic carbon (TOC) and cassava yield indicators. The experiment was conducted on a family farm in Santarém, Brazil, in a randomized block design, with four treatments and five replications. Treatments were as follows: T1, unfertilized soil (control); T2, NPK fertilizer; T3, poultry manure; and T4, cattle manure. The variables analyzed were soil TOC, shoot fresh weight, plant height, marketable stem diameter, marketable root yield, and yield. Data were subjected to analysis of variance, Tukey’s test (p < 0.05), hierarchical clustering, and principal component analysis. Application of organic fertilizers (T3 and T4) increased soil TOC levels. Chemical fertilizer treatment (T2) resulted in the highest shoot fresh weight, yield, and marketable root yield. Marketable stem diameter was positively influenced by T2 and T4. There were no significant treatment effects on plant height. Hierarchical clustering isolated organic fertilizers (T3 and T4) from other treatments. Principal component analysis revealed two principal components, which together explained 87.77% of the total variance. Organic fertilizer application provided the highest TOC accumulation during the experimental period, whereas NPK fertilization was the most effective in increasing cassava yield in the first year of cultivation

Yield and Nutritional Quality of Green Leafy Lettuce (Lactuca sativa L.) under Soilless Culture System Using Various Composition of Growing Media and Vermicompost Rates

<p>Soilless culture system (SCS) production is preferred because it is more hygienic and highly nutritious and free of chemical pesticides. However, the application of organic fertilizers in SCS for green vegetable cultivation is still rarely used. This study was to test various growing media compositions and vermicompost rates on green lettuce's nutritional quality. Four types of growing media (using the mixture of cocopeat, zeolite, rice husk biochar and sand) and five levels of vermicompost rates (50-250 g pot<sup>-1</sup>) were tested. The greatest total fresh weight and marketable yield were found using 55% cocopeat, 30% rice husk biochar and 15% sand with a vermicompost rate of 250 g pot<sup>-1</sup>. The highest nutritional quality of green lettuce as measured by the highest content of chlorophyll A, B, the total chlorophyll and calcium (Ca) was found in the composition of cocopeat 55%, zeolite 30% and sand 15%. As was, the highest mineral content of of potassium (K) and phosphorus (P). Good quality lettuce was found in growing media using 30% biochar with a vermicompost rates of 200-250 g pot<sup>-1</sup> and growing media using 30% zeolite with a vermicompost rates of 150-200 g pot<sup>-1</sup>. Thus, the admixtures of biochar and zeolite into the cocopeat substrate for the soilless culture system of green leafy lettuce significantly affected yield and nutritional quality.</p>

Successive Harvests Modulate the Productive and Physiological Behavior of Three Genovese Pesto Basil Cultivars

In the Italian culinary tradition, young and tender leaves of Genovese basil (Ocimum basilicum L.) are used to prepare pesto sauce, a tasty condiment that attracts the interest of the food processing industry. Like other leafy or aromatic vegetables, basil is harvested more than once during the crop cycle to maximize yield. However, the mechanical stress induced by successive cuts can affect crucial parameters associated with pesto processing (leaf/stem ratio, stem diameter, and dry matter). Our research accordingly aimed to evaluate the impact of successive harvests on three field-grown Genovese basil cultivars (“Aroma 2”, “Eleonora” and “Italiano Classico”) in terms of production, physiological behavior, and technological parameters. Between the first and second harvest, marketable fresh yield and shoot dry biomass increased by 148.4% and 172.9%, respectively; by contrast, the leaf-to-stem ratio decreased by 22.5%, while the dry matter content was unchanged. The increased fresh yield and shoot dry biomass at the second harvest derived from improved photosynthetic efficiency, which enabled higher net CO2 assimilation, Fv/Fm and transpiration as well as reduced stomatal resistance. Our findings suggest that, under the Mediterranean environment, “Italiano Classico” carries superior productive performance and optimal technological characteristics in line with industrial requirements. These promising results warrant further investigation of the impact successive harvests may have on the qualitative components of high-yielding basil genotypes with respect to consumer expectations of the final product.

Cultural Management Practices for Commercial Tigernut Production in Southern Ontario, Canada

To foster development of Ontario commercial tigernut (Cyperus esculentus var. sativus) production, this study was conducted to identify cultural management practices that increase tuber yields. The agronomic practices of field preparation (hilled vs. not hilled), regular irrigation vs. natural rainfall, varying rates of nitrogen (N) fertility, and early season weed management were evaluated. Irrigation had no significant impact on total fresh weight, dry weight, and marketable yield over 2 growing seasons. Similarly, yields from plants grown in hilled rows vs. flat beds over two seasons showed no significant differences. Tigernut yields did not show a response to increasing rates of N up to 150 kg·ha−1. A critical weed-free period of 3 weeks resulted in an 844% yield increase over the nonweeded control. Overall, the results indicate that in general, tigernut requires few inputs to produce a viable commercial yield under Ontario growing conditions.

Modeling the effects of long-term reduced N application on soil N losses and yield in a greenhouse tomato production system

Overuse of N fertilizer in intensive greenhouse vegetable production systems (GVPS) seriously affects soil and water environment. Quantifying soil N dynamics and plant growth is crucial for developing sustainable N management practices. A long-term greenhouse tomato experiment, including 13 tomato growth seasons (2004–2010) and three different nitrogen (N) management practices (conventional N management, CN; reduced N management, RN; and manure N management, MN), was conducted in this study. Agricultural system model (WHCNS_Veg) was adopted to simulate and analyze the effects of different long-term N fertilization regimens on N loss and tomato yield. The calibration and evaluation of the model showed fairly satisfactory simulation in soil water content, soil nitrate concentration, crop N uptake, and fresh marketable tomato yield; the values of the normalized root mean square error (NRMSE) were 15.4%, 42.9%, 21.2%, and 7.7%, respectively, and the values of index of agreement (IA) were 0.85, 0.62, 0.96, and 0.97, respectively. Different N management practices did not significantly affect the tomato yield. However, the long-term high rates of chemical N application in CN treatment significantly increased soil N accumulation, thereby increasing N loss. The simulated N losses caused by leaching, denitrification, and ammonia volatilization under the reduced N treatments (RN and MN) were decreased by 66.8%, 56.8%, and 83.2% compared to those of CN treatment, respectively. Among different N management practices, manure N management showed a relatively high N use efficiency and maintained a high tomato yield. And the optimal manure N application rate approximately 400 kg N ha−1 yr−1 was recommended to maximize farmers' income. The results not only provide decision supports for local farmers' N management, but also policy making of government for sustainable development of greenhouse tomato production in the region.

Appraisal of Biodegradable Mulching Films and Vegetal-Derived Biostimulant Application as Eco-Sustainable Practices for Enhancing Lettuce Crop Performance and Nutritive Value

Scientists, extensions specialists, and growers are seeking sustainable agricultural practices that are able to cope with these objectives in order to ensure global food security and minimize environmental damage. The use of mulching films and plant biostimulants in agriculture seems to be a valid solution for tackling these rising concerns. A greenhouse experiment was conducted in order to elucidate the morpho-physiological and nutritive characteristics of lettuce (Lactuca sativa L.) in response to foliar application of a tropical plant extract (PE) biostimulant and the use of plastic mulches. Two biodegradable mulch treatments (Mater-Bi® 1 and Mater-Bi® 2) were compared to black polyethylene (LDPE) and bare soil. Biodegradable mulch film Mater-Bi® 1 produced a comparable marketable fresh yield to the commercial standard polyethylene (LDPE), whereas Mater-Bi® 2 exhibited the highest crop productivity. When averaged over biostimulant application, lettuce plants grown with biodegradable film Mater-Bi® 2 exhibited superior quality traits in terms of K, Ca, total ascorbic acid, and carotenoids content. The combination of film mulching (LDPE, Mater-Bi® 1 or Mater-Bi® 2) with the tropical plant extract biostimulant exhibited a positive and significant synergistic effect (+30%) on yield. The PE-biostimulant induced higher values of SPAD index and total chlorophyll content when compared to untreated greenhouse lettuce. The mineral content of leaf tissues was greater by 10% and 17% (for P and Ca, respectively) when compared to the untreated lettuce (no PE application). Nitrate content was significantly reduced by 23% in greenhouse lettuce plants receiving PE as compared to the untreated control. The positive effect of Mater-Bi® 2 film on the ascorbic acid content has also been highlighted when combined with the biostimulant application, where a major amplification of total ascorbic acid (+168%) was recorded in comparison to the untreated lettuce. Overall, our work can assist leafy vegetables growers in adopting good agricultural practices, such as biodegradable plastic mulches and vegetal-derived biostimulants, to improve the sustainability of greenhouse production.

FLOWER BUD REMOVAL AND EARTHING UP TIME INCREASED GROWTH AND TUBER YIELD OF POTATO AT EASTERN TIGRAY, ETHIOPIA

<p class="abstrakinggris">In Ethiopia, potato is a staple food crop and source of cash income for smallholder farmers, but the national average yield in farmers’ field is lower than experimental yields due to poor agronomic activities. The study aimed to determine the effects of flower removal and earthing up time on growth and tuber yield of potato. The experiment comprised of three flower removal stage and five earthing up time treatments, which were laid out in a randomized complete block design of 3x5 factorial arrangements with three replications. Results indicated that plant height, stem number, tuber length and tuber diameter were shown significantly affected (p < 0.05) by the main effect of flower removal and earthing up time but not by their interaction. Fresh shoot biomass and physiological maturity were recorded significantly affected (p < 0.05) by earthing up time, but not by flower removal stage and its interaction with earthing up time. Total fresh biomass, marketable and unmarketable tuber yield, as well as total tuber yield were significantly affected (p < 0.05) by main factors and their interaction effects. The results clearly indicated that the highest total tuber yield (30.96 ton ha<sup>-1</sup>) was recorded from flower bud removed potato earthed up at 15 days after complete emergence. Therefore, flower bud removed potato earthed up at 15 days after full emergence was better in terms of all yield contributing characters and tuber yield.</p><em></em><em></em>

Endophytic fungi induce salt stress tolerance in greenhouse-grown basil

In many irrigated regions of Mediterranean areas, vegetable farmers are forced to use low quality water (often with elevated salinity) for their crops with important losses in productivity. Sweet basil (Ocimum basilicum L.) is one of the most important aromatic herbs cultivated in Italy under both open-field and protected conditions. The application of endophytic fungi such as mycorrhizal fungi and Trichoderma could be an efficient tool to mitigate the detrimental effect of salinity. A greenhouse experiment was carried out to assess the influence of co-inoculation of endophytic fungi and plant growth promoting rhizobacteria on yield and quality traits under non-saline (1 mM NaCl) and saline (40 mM NaCl) conditions. Increasing the NaCl concentration in the nutrient solution in both inoculated and non-inoculated plants decreased the yield and growth parameters but increased the quality traits in particular the hydrophilic and lipophilic antioxidant activities and total phenols. The microbial-based biostimulant markedly enhanced the marketable fresh yield by 17.0% compared to control plants. The better crop performance of inoculated basil has been attributed to a better pigment biosynthesis (i.e., higher SPAD index). On the other hand, the nitrate content in microbial biostimulant basil plants was significantly reduced by 16.1%, whereas the total phenols increased by 7.7% compared to untreated plants. Overall, the use of beneficial microorganisms could be adopted as a sustainable tool in vegetable cropping systems to mitigate the detrimental effect of saline water.

Effect of Vegetal- and Seaweed Extract-Based Biostimulants on Agronomical and Leaf Quality Traits of Plastic Tunnel-Grown Baby Lettuce under Four Regimes of Nitrogen Fertilization

Nitrogen (N) fertilizers play a crucial role in agriculture, representing a powerful tool for farmers for increasing yields throughout the seasons under both optimal and suboptimal conditions. At the same time, their synthetic/chemical nature could have several influences on ecosystems and human health. For this reason, there is an urgent need to find new and more sustainable means of production to increase plant productivity and optimize nitrogen use. An experiment was conducted in a plastic tunnel to assess the response of baby lettuce crop to the foliar application of three plant biostimulants (PBs): Legume-derived protein hydrolysate (LDPH) ‘Trainer®’, tropical plant extract (TPE) ‘Auxym®’ and seaweed extract (SwE) from Ecklonia maxima ‘Kelpak®’ under different N rates of 0, 10, 20 and 30 kg N·ha−1. The responses of baby lettuce plants were assessed in terms of yield, growth parameters and physicochemical composition of the leaves. The fresh yield of baby lettuce in both biostimulant-treated and untreated plants was positively affected by increasing N rates from 0 to 20 kg N·ha−1, reaching a plateau thereafter indicating luxury N conditions at 30 kg N·ha−1. However, high N fertilizer application (20 and especially 30 kg N·ha−1) resulted in undesirable decreases in antioxidant activities and total ascorbic acid (TAA). Under non-fertilized regimens, foliar PBs application boost growth and yield of baby lettuce in comparison to non-treated plants. Foliar spray with LDPH and especially SwE elicited significant increases in marketable fresh yield (averaging 14%, 6% and 7% at 10, 20 and 30 kg N·ha−1, respectively) compared to TPE and untreated plants. Improved agronomical performance of baby lettuce under optimal (10 kg N ha−1) and especially suboptimal N regimens (0 kg N ha−1) was associated with increasing photochemical efficiency and a better activity of photosystem II (higher Soil Plant Analysis Development-SPAD index and chlorophyllous pigments biosynthesis). The application of LDPH enhanced antioxidant capacity and TAA in baby lettuce leaf and did not increased nitrate content as recorded in SwE and TPE treatments. Overall, plant biostimulants may be considered as a sustainable tool of production to increase leafy vegetable productivity in low fertility soils.

Effect of Biochar of Grass, <i>Chat</i> and Inorganic Fertilizer on the Growth and Yield of Garden Vegetable at Benishangulgumze Region, Ethiopia

Biochar is a relatively recent term used to denote charcoal used as an agricultural input into soils. The idea comes from the use of charcoal in the Amazon on deep, highly leached, and infertile soils by Amazonian peoples in pre-Columbian times. Biochar differs most significantly from charcoal in its primary use; rather than fuel, it is primarily used for the amendment of soils (enhancing their fertility) and sequestration of carbon. One of the distinguishing properties of biochar that allows it to be a long-term carbon sink is its high stability in the environment relative to other types of organic carbon substances. Currently, however, very little or no biochar is utilized in Ethiopia particularly at Benishangulgumze Region for agriculture, in part because of its agronomic value in terms of crop response and soil health benefits have yet to be quantified, and because of the mechanisms by which it improves soil fertility are poorly understood. Therefore, the research is focused on converting the biomass of grasses and chat in to biochar in the process of pyrolysis for yield improvement, soil amendment and environmental pollution reduction. Findings of this research shows environmental pollution that regenerating from chat waste around the town, CO2 gas emission from grass when it is burning become reduced, soil physiochemical properties make improvements by using these waste as biochar instead of throwing everywhere and farmer’s cost of buying inorganic fertilizer by using biochar of grass and chat waste as organic fertilizer have significant reduction. Biochar of grass and inorganic fertilizer was required to realize significant increases in fresh marketable bulb yield of onion on the experimental soil. Environmental pollution can reduced through making biochar from the polutants. Chat and grass biochar should used for briquette energy source to save the environment from pollution beside use as fertilizer. Modern technologies are required during preparation of biochar because during making biochar there are gas emit to the atmosphere but can used as ethanol or syngagass for substitute fuels determination of methane formed through decomposing waste of grass and chat is required.

Marketable yield and nutritional composition of amaranths in response to fertiliser

Field experiments were conducted at the University of Limpopo, Syferkuil and Lwamondo Experimental Farms during the 2006/2007 and 2007/2008 growing seasons to determine the effect of nutrient input dynamics on marketable yield and nutritional compositions of two Amaranthus species. A. hybridus and A. hypochondriacus were planted in a 2×6 factorial split-plot experiment using a randomised complete block design replicated three times. Organic fertilizer (poultry manure) and inorganic fertilizer (LAN/urea) were applied at rates equivalent to 0, 50, 75, 100, 125 and 150 kg N ha-1. Application of fertilzer increased marketable yield of amaranth, irrespective of location, source of nitrogen and the species of the amaranth. Interactions between amaranth species and nitrogen fertilizer application were significant (P≤0.05) for fresh marketable mass of amaranth. Both Amaranthus species also differed significantly in fresh marketable yield. The highest fresh leaf mass of 91 g plant-1 was obtained for A. hybridus compared to 82 g plant-1 obtained for A. hypochondriacus with with 150 kg ha-1 N treatment at 12 WAT. For inorganic N source, A. hybridus had higher average dry matter value of 91.2% and protein content of 5.1% compared to 90.8 and 3.2% of dry matter and protein contents, respectively, in A. hypochondriacus. Amaranths grown in inorganic fertiliser treated soils had higher dry matter and protein contents fibre contents than that grown in organic fertilizer treated soils.

Real-time irrigation: Cost-effectiveness and benefits for water use and productivity of strawberries

Although California is experiencing permanent water deficits compensated by irrigation, the state accounts for more than 90% of total strawberry production in the United States. There is a critical need to optimize yield and crop water productivity (CWP), as influenced by irrigation management. Although studies have reported that irrigation management based on soil matric potential (ѱ) has the potential to increase yield and CWP compared to conventional practices, the cost of this technology may be a limiting factor for some growers. In this study, we assessed the cost-effectiveness of wireless tensiometer technology (WTT) for field-grown strawberries in California in comparison with the conventional irrigation management. As a second step, we evaluated the cost-effectiveness of deficit irrigation. Using data from eight sites, we calculated multiple linear regressions (MLR) to describe the relationship between: (1) fresh market yield and average soil matric potential reached before irrigation initiation (ѱirr) and (2) water use and ѱirr. Based on MLR results, we evaluated the technical performance of each irrigation management method and conducted an economic analysis. Our results showed that adopting a precise irrigation scheduling tool such as WTT is cost-effective and leads to water savings relative to conventional irrigation. Our results also revealed that any water savings associated with a deficit irrigation strategy are costly for strawberry growers.

Agronomic performance of new open pollinated experimental lines of broccoli (Brassica oleracea L. var. italica) evaluated under organic farming.

In order to develop new open pollinating cultivars of broccoli for organic farming, two experiments were conducted during fall 2015 and spring 2016. This study was aimed at comparing the agronomic performance of eleven new open pollinating breeding lines of broccoli to introduce new lines and to test their seasonal suitability for organic farming. Field experiments were carried out at the organic research station Kleinhohenheim of the University of Hohenheim (Stuttgart-Germany). Different agronomic traits total biomass fresh weight, head fresh weight, head diameter, hollow-stem, fresh weight harvest index and marketable yield were assessed together with commercial control cultivars. The data from both experiments were analyzed using a two-stage mixed model approach. In our study, genotype, growing season and their interaction had significant effects on most traits. Plants belonging to the fall growing season had bigger sizes in comparison to spring with significantly (p< 0.0001) higher biomass fresh weight. Some experimental lines had significant lower head fresh weight in spring in comparison to the fall season. The high temperature during the harvest period for the spring season affected the yield negatively through decreasing the firmness of broccoli heads. The low average minimum temperatures during the spring growing season lead to low biomass fresh weight but high fresh weight harvest index. Testing the seasonal suitability of all open pollinating lines showed that the considered fall season was better for broccoli production. However, the change in yield between the fall and the spring growing season was not significant for “Line 701” and “CHE-MIC”. Considering the expression of different agronomic traits, “CHE-GRE-G”, “Calinaro” and “CAN-SPB” performed the best in the fall growing season, and “CHE-GRE-G”, “CHE-GRE-A”, “CHE-BAL-A” and “CHE-MIC” and “Line 701” were best in the spring growing season, specifically due to the highest marketable yield and proportion of marketable heads.

Morphophysiological Traits and Nitrate Content of Greenhouse Lettuce as Affected by Irrigation with Saline Water

In a 2-year study, the morphophysiological and qualitative changes imposed to greenhouse lettuce (Lactuca sativa L.) by an increasing concentration of NaCl in the irrigation water were determined. Plants were grown under soil conditions and supplied with irrigation water having electrical conductivities (ECs) of 0.7 (control), 0.9, 1.8, 3.6, or 7.2 dS·m−1. Irrigation with saline water resulted in linear decrease in plant growth parameters (i.e., leaf number, total leaf area and head diameter), head fresh weight, and diameter as well as yield, especially at 1.8, 3.6, and 7.2 dS·m−1, confirming that lettuce is a salt-sensitive crop. The percentage of marketable yield reduction in comparison with nonsaline control treatment was 22.7%, 36.4%, 45.4%, and 63.6% at 0.9, 1.8, 3.6, and 7.2 dS·m−1, respectively. The reduction in marketable fresh yield has been partly compensated by a decrease in the nitrate content of salt-treated lettuce. The highest values of hydrophilic antioxidant activity were recorded in the nonsalinized treatment. The lowest values of lipophylic antioxidant activity (LAA) and total ascorbic acid were observed under severe stress conditions (7.2 dS·m−1). Net CO2 assimilation rate and leaf water potential (LWP) declined with increasing NaCl concentration in the irrigation water. Increasing salinity in the irrigation water induced a reduction in stomatal conductance (gs) as LWP dropped below −0.62 MPa.

Developing a water and nitrogen management model for greenhouse vegetable production in China: Sensitivity analysis and evaluation

Excessive water and fertilizer inputs have led to a series of environmental problems in vegetable production areas in China. Identifying the fates of water and nutrients is crucial to develop best management strategies in intensive vegetable production systems. The objectives of this study were to (i) develop a scientific water and nitrogen (N) management tool for intensive greenhouse vegetable production in China, and (ii) evaluate the model performance in the simulating the fate of water and N, and vegetable growth under different water and N management practices in China. A vegetable growth component was added to the field soil-crop system model WHCNS (soil Water Heat Carbon Nitrogen Simulator), named WHCNS_Veg. Parameters for the model were estimated and a sensitivity analysis was conducted by coupling the model with the model-independent parameter estimation program (PEST). Data used to test the model came from two years of cucumber and tomato experiments with various water and N combinations in Shandong province, China. The results of sensitivity analysis showed that the soil hydraulic parameters and vegetable genetic parameters had a relatively higher sensitivity compared with those of N transformation parameters. The saturated soil water content had the highest sensitivity among soil hydraulic parameters, and the total available accumulated temperature, crop coefficient and maximum root depth had higher sensitivity for both vegetable crops. Among the N transformation parameters, the parameters related to nitrification had the highest sensitivity. The automatic optimization algorithm performed well in adjusting soil hydraulic parameters, vegetable genetic parameters and N transformation parameters. The normalized root mean square error for soil water content, soil nitrate concentration, marketable fresh yield and vegetable N uptake were 5.7%, 28.0%, 2.7% and 8.3%, respectively, and indices of agreement were 0.727, 0.730, 0.997 and 0.832, respectively. The results indicated that the WHCNS_Veg model has great potential to simulate and analyze water and N fates, and vegetable growth for the intensive greenhouse vegetable production in China.

Yield and crop growth of table potato affected by different split-N fertigation regimes in sandy soil

Abstract To explore the response of yield, crop growth as well as water and N use efficiency to different fertigation regimes, three years field experiment were carried out. The factors in the experiment comprised five N levels providing 0, 60, 100, 140 and 180 kg N ha−1, and one real time model (Daisy model)-based N fertilization method, as well as three irrigation levels. Results showed that prolonged N fertigation increased yield consistently but N fertigation should be carried out early so that shoot growth is optimized and prolonged N have sufficient time to take effect on tuber yield accumulation. In all three years, the highest fresh yield and marketable yield was obtained when 180 kg N ha−1 was applied. Compared to the 180 kg N ha−1 treatment, real-time model-based N fertilization resulted in comparable yield (not different) in all seasons. Nevertheless, model-based N fertilization resulted in yield that was significantly lower than the predicted maximum yield across the seasons, implying the necessity to adjust the parameters related to critical N concentration of Daisy model. The economic optimal were 142, 194 and 195 kg N ha−1 in 2013, 2014 and 2015, respectively. Deficit irrigation did not cause reduced soil water content, ratio vegetation index (RVI) and yield, but irrigation efficiency was increased significantly in 2013.