scholarly journals Soil Monitoring Methods to Assess Immediately Available Soil N for Fertigated Sweet Pepper

Agronomy ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 2000
Author(s):  
Alejandra Rodríguez ◽  
M. Teresa Peña-Fleitas ◽  
Francisco M. Padilla ◽  
Marisa Gallardo ◽  
Rodney B. Thompson

Excessive N application occurs in greenhouse vegetable production. Monitoring methods of immediately available soil N are required. [NO3−] in soil solution, sampled with ceramic cup samplers, and [NO3−] in the 1:2 soil to water (v/v) extract were evaluated. Five increasing [N], from very N deficient (N1) to very N excessive (N5) were applied throughout three fertigated pepper crops by combined fertigation/drip irrigation. The crops were grown in soil in a greenhouse. Soil solution [NO3−] was measured every 1–2 weeks, and extract [NO3−] every 4 weeks. Generally, for treatments N1 and N2, both soil solution and extract [NO3−] were continually close to zero, and increased with applied [N] for treatments N3–5. The relationships of both methods to the nitrogen nutrition index (NNI), an indicator of crop N status, were assessed. Segmented linear analysis gave R2 values of 0.68–0.70 for combined data from entire crops, for both methods. NNI was strongly related to increasing [NO3−] up to 3.1 and 0.9 mmol L−1 in soil solution and extracts, respectively. Thereafter, NNI was constant at 1.04–1.05, with increasing [NO3−]. Suggested sufficiency ranges were derived. Soil solution [NO3−] is effective to monitor immediately available soil N for sweet pepper crops in SE Spain. The extract method is promising.

Agronomy ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 819
Author(s):  
M. Teresa Peña-Fleitas ◽  
Marisa Gallardo ◽  
Francisco M. Padilla ◽  
Alejandra Rodríguez ◽  
Rodney B. Thompson

A rapid analysis ion-selective electrode (ISE) system for measurement of [NO3−] in nutrient solution (NS), soil solution (SS) and petiole sap (PS) was evaluated. For each material, there were 797–2010 samples from 5 to 6 different crops, and from 2 to 4 different species. Accuracy was evaluated by linear regression (LR) with laboratory analysis (automated colorimetry, Cd reduction), and by relative error (RE), the average percentage deviation from laboratory analysis. For NS, the LR was y = 0.982x + 0.76, R² = 0.962 (n = 2010), for combined data from 5 crops (3 pepper, 2 cucumber). For SS, the LR was y = 0.975x + 1.13, R² = 0.965 (n = 797), for combined data from 5 crops (3 pepper, 2 cucumber). For undiluted PS, the LR relationship was y = 0.742x + 168.02, R² = 0.892 (n = 1425), for combined data from 6 crops (3 pepper, 2 cucumber, 1 melon). The underestimation was most pronounced at [NO3−] of >1500 mg NO3−–N L−1. For diluted petiole sap (dilution by 10 for pepper and melon, 5 for other species), the LR relationship was y = 1.010x + 99.26, R² = 0.927 (n = 1182), for combined data from 6 crops (2 pepper, 2 cucumber, 1 melon, 1 tomato). RE values for all measurements in composite datasets were 14%, 22%, 24% and 25% for NS, SS, undiluted PS and diluted PS respectively, and they were lower in concentrations most likely to be measured in practical on-farm work. The ISE system measured [NO3−] in NS, SS and diluted PS with sufficient accuracy to effectively guide on-farm decision making.


2020 ◽  
Vol 12 (5) ◽  
pp. 763 ◽  
Author(s):  
Romina de Souza ◽  
M. Teresa Peña-Fleitas ◽  
Rodney B. Thompson ◽  
Marisa Gallardo ◽  
Francisco M. Padilla

Vegetation indices (VIs) can be useful tools to evaluate crop nitrogen (N) status. To be effective, VIs measurements must be related to crop N status. The nitrogen nutrition index (NNI) is a widely accepted parameter of crop N status. The present work evaluates the performance of several VIs to estimate NNI in sweet pepper (Capsicum annuum). The performance of VIs to estimate NNI was evaluated using parameters of linear regression analysis conducted for calibration and validation. Three different sweet pepper crops were grown with combined irrigation and fertigation, in Almería, Spain. In each crop, five different N concentrations in the nutrient solution were frequently applied by drip irrigation. Proximal crop reflectance was measured with Crop Circle ACS470 and GreenSeeker handheld sensors, approximately every ten days, throughout the crops. The relative performance of VIs differed between phenological stages. Relationships of VIs with NNI were strongest in the early fruit growth and flowering stages, and less strong in the vegetative and harvest stages. The green band-based VIs, GNDVI, and GVI, provided the best results for estimating crop NNI in sweet pepper, for individual phenological stages. GNDVI had the best performance in the vegetative, flowering, and harvest stages, and GVI had the best performance in the early fruit growth stage. Some of the VIs evaluated are promising tools to estimate crop N status in sweet pepper and have the potential to contribute to improving crop N management of sweet pepper crops.


Sensors ◽  
2019 ◽  
Vol 19 (8) ◽  
pp. 1807 ◽  
Author(s):  
Silke Hemming ◽  
Feije de Zwart ◽  
Anne Elings ◽  
Isabella Righini ◽  
Anna Petropoulou

The global population is increasing rapidly, together with the demand for healthy fresh food. The greenhouse industry can play an important role, but encounters difficulties finding skilled staff to manage crop production. Artificial intelligence (AI) has reached breakthroughs in several areas, however, not yet in horticulture. An international competition on “autonomous greenhouses” aimed to combine horticultural expertise with AI to make breakthroughs in fresh food production with fewer resources. Five international teams, consisting of scientists, professionals, and students with different backgrounds in horticulture and AI, participated in a greenhouse growing experiment. Each team had a 96 m2 modern greenhouse compartment to grow a cucumber crop remotely during a 4-month-period. Each compartment was equipped with standard actuators (heating, ventilation, screening, lighting, fogging, CO2 supply, water and nutrient supply). Control setpoints were remotely determined by teams using their own AI algorithms. Actuators were operated by a process computer. Different sensors continuously collected measurements. Setpoints and measurements were exchanged via a digital interface. Achievements in AI-controlled compartments were compared with a manually operated reference. Detailed results on cucumber yield, resource use, and net profit obtained by teams are explained in this paper. We can conclude that in general AI performed well in controlling a greenhouse. One team outperformed the manually-grown reference.


2004 ◽  
Vol 84 (2) ◽  
pp. 169-176 ◽  
Author(s):  
B. L. Ma ◽  
M. Li ◽  
L. M. Dwyer ◽  
G. Stewart

Little information is available comparing agronomic performance and nitrogen use efficiency (NUE) for N application methods such as foliar spray, soil application, and ear injection in maize (Zea mays L.). The objective of this study was to investigate the effects of various N application methods on total stover dry matter, grain yield, and NUE of maize hybrids using a 15N-labeling approach. A field experiment was conducted on a Dalhousie clay loam in Ottawa and a Guelph loam in Guelph for 2 yr (1999 and 2000). Three N application methods were tested on two maize hybrids, Pioneer 3893 and Pioneer 38P06 Bt. At planting, 60 kg N ha-1 as ammonium nitrate was applied to all treatments. In addition, 6.5 kg N ha-1 and 13.5 kg N ha-1 as 15N-labeled urea were applied to either foliage (Treatment I) or soil (Treatment II) at V6 and V12 stages, respectively. In Treatment III, 20 kg N ha-1 as 15N-labeled urea was injected into space between ear and husks at silking. The results showed that compared with soil N application neither foliar spray nor injection through ear affected grain yield or stover dry matter. The NUE values ranged from 12 to 76% for N fertilizer applied at V6 a nd V12 stages, or at silking for all treatments. There was no interaction of hybrid × N application methods on any variables measured with the only exception that for soil N application, grain NUE in Pioneer 38P06 Bt was significant higher than in Pioneer 3893. The difference in total N and NUE of grain and stover between soil N application and foliar N spray was inconsistent. However, NUE was substantially higher for N injection through the ear than for foliar or soil application without differential responses between the two hybrids. Nitrogen injection through the ear at silking might have altered N redistribution within the plant and improved NUE. Hence, it can potentially enhance grain protein content. Foliar N spray is not advocated for maize production in Ontario. Key words: Maize, Zea mays, nitrogen application methods, nitrogen-15, yield, nitrogen use efficiency


Author(s):  
Bilge Gözener ◽  
Halime Dereli

Tomato comes as the most commonly produced, consumed and subject for trading in the world. Alongside fresh consumption, on the other hand it forms the most significant raw material source of food industry, especially for tomato paste, frozen and dried vegetable-fruit and canned food industry. Turkey's greenhouse vegetable production field for 2016 year is 675173 decars and Antalya forms 51% of this field. Tomato forms 61.72% of Antalya's greenhouse production. The main material of the research consists of interviews made with producers resided in 5 villages/towns, where greenhouse tomato production is carried out densely in Antalya city, Alanya district. In 48 villages and towns, greenhouse tomato production is carried out, according to the official records. In the chosen areas, 365 producers exist. 20% of these producers (73) form the sample size. In the research, it was determined that the producers' average agricultural land possession is 9.13 decars and in 40.53% of these areas they grew tomatoes. None of these producers are engaged in contractual growing. All of the yield is produced for the edible (as table-top item). After the harvest, all of the products are sold in the wholesales market in county and city. 7.89% of the producers have no information on soilless agriculture, as 10.52% of them think that it has no advantages and 73.36% of them recommend traditional agriculture.


2011 ◽  
Vol 91 (4) ◽  
pp. 521-531 ◽  
Author(s):  
Xianglan Li ◽  
Noura Ziadi ◽  
Gilles Bélanger ◽  
Zucong Cai ◽  
Hua Xu

Li, X., Ziadi, N., Bélanger, G., Cai, Z. and Xu, H. 2011. Cadmium accumulation in wheat grain as affected by mineral N fertilizer and soil characteristics. Can. J. Soil Sci. 91: 521–531. Cadmium (Cd) is a heavy metal distributed in soil by natural processes and anthropogenic activities. It can accumulate in crops, such as spring milling wheat (Triticum aestivum L.), and its accumulation depends on crop species, soil factors, and agricultural practices like fertilizer inputs. Our objective was to study the effect of mineral N fertilizer and soil characteristics on wheat grain Cd concentration. A field study was conducted over 12 site-years (2004–2006) in Québec, with four N application rates (0, 40, 120, and 200 kg N ha−1). Wheat grain samples (n=192) were analysed for their Cd and N concentrations. Soil samples (n=48) taken before N fertilizer application were characterised for their chemical and physical properties, including Mehlich-3 extractable Cd concentration. Wheat grain Cd concentration increased significantly with increasing N application rates at 11 of the 12 site-years. Averaged across the 12 site-years, Cd concentration ranged from 53 µg kg−1dry matter (DM) without N applied up to 87 µg kg−1DM when 200 kg N ha−1was applied. Wheat grain Cd concentration also varied significantly with site-years (34–99 µg kg−1DM), but never exceeded the proposed tolerance for wheat grain of 235 µg kg−1DM. Wheat grain Cd concentration was significantly related to Mehlich-3 extractable Cd in soil (R2=0.44, P=0.021) and nitrogen nutrition index (R2=0.69, P=0.001). We conclude that soil Cd concentration and the crop N nutrition status affect Cd accumulation in spring wheat grain produced in eastern Canada.


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