Open Access Short Research Article

Pressure-discharge and Hydraulic Gradient along the Lateral of the Drip Irrigation System for Okra

S. Vanitha, S. Senthilvel

Journal of Experimental Agriculture International, Page 1-6
DOI: 10.9734/jeai/2019/v34i330173

Micro irrigation system should ensure relatively same amount of water to each plant along the total length of lateral line. In general, the drip irrigation systems are low to medium operating pressure head systems with a pressure requirement in range of 0.5 kg/cm2 to 2.5 kg/cm2 depending on the area irrigated and field layout geometry. However, since these systems are pressure irrigation systems which require appropriate operating pressure heads to deliver the required rates of flow, the inevitable frictional head losses are to be compensated for maintaining uniformity in water application. Hence, the hydraulic gradient compensation needs to be achieved by some viable mechanism so that the inequality in pressure heads and discharges can be eliminated or minimized. The crop production will have its maximum yield and water use efficiency only one the water distribution uniformities at its the highest. Hydraulic gradient compensation assumes a vital role in compensating the operating pressure heads as well as the emitter discharges. The hydraulic gradient compensated drip lateral layout registered high order of water distribution uniformity in the range of 97.8% and irrigation usage efficiency in the range of 17.98 kg/ha/mm to 20.69 kg/ha/mm for 2 lph emitter arrangements.

Open Access Short Research Article

Planting Spacing of Cultivated Soybean Intercropped with Cover Plants

Thatyele Sousa dos Santos, José de Anchieta Alves de Albuquerque, Roberto Dantas de Medeiros, Paulo Roberto Ribeiro Rocha, José Maria Arcanjo Alves, Thaís Santiago Castro, Anderson Carlos de Melo Gonçalves, Ana Karyne Pereira Melo

Journal of Experimental Agriculture International, Page 1-9
DOI: 10.9734/jeai/2019/v34i330176

Aims: The objective of this work was to evaluate the influence of planting spacing in soybean intercropped with covering species in the Roraima savanna.

Study Design: The experimental design was a randomized complete block design with four replications.

Place and Duration of Study: The experiments were conducted at Embrapa Roraima, in Campo Experimental Água Boa, municipality of Boa Vista - Roraima state, in 2015 and 2016.

Methodology: Plots consisted in the spacing (0.45, 0.55 and 0.65 m) and the subplots were constituted by the cover plant species Urocloa brizantha, Urocloa ruziziensis, Panicum maximum and the treatment without intercropping. The used soybean cultivar was BRS Tracajá in two crops. The following variables had evaluated: plant height, number of grains per pod, number of pods per plant, 100-grain weight, plant dry matter, insertion of the first pod, grain yield, and dry matter of the covering species and of spontaneous vegetation.

Results: Cover plants affected the plant height, number of pods per plant, insertion of the first pod, dry matter of cover species and yield of grains in soybean. The spacing did not influence the growth and production of the soybean crop, except positively in the number of pods per plant with the increased of spacing. The interaction of cover plants and spacing affected the weight of 100 grains, the insertion of the first pod and the dry mass of the cover species. Number of grains per pod and the dry mass of the soybean plants were not affected by the cover plants and by the spacing.

Conclusion: The U. brizantha species provids the highest production of dry matter intercropped with soybean, however, the yield of the crop decrease. The U. ruziziensis species is the most suitable for the cultivation intercropped with the crop. The used spacing do not influence the productivity.

Open Access Original Research Article

Evaluation of Ethiodemethrin 2.5% EC and Karate 5% against Citrus Leafminer at Metahara Citrus Orchard

Leul Mengistu, Netsanet Ayele

Journal of Experimental Agriculture International, Page 1-6
DOI: 10.9734/jeai/2019/v34i330174

The study was conducted at Metahara Sugar Factory Citrus orchard fields in 2010/11 cropping season with the objective of evaluating the efficacy of Ethiodemethrin 2.5% EC and Karate 5% for the control of citrus leafminer. In this study, seven treatments were used i.e. Ethiodemethrin 2.5% EC at 20, 30 and 50 ml per tree and Karate 5% EC at 0.72 and 1.10 ml per tree including free checks. Treatments were given at once and twice application frequencies; the second application was applied after fifteen days of the first application. The experiment was laid out in randomized complete block design with four replications. The study indicated that Ethiodemethrin 2.5% EC at 20, 30 and 50 ml tree-1 and Karate 5% EC at 0.72 and 1.10 ml tree-1 had satisfactory control potential of citrus leafminer (CLM) for a maximum of two weeks period as compared to the untreated check. Therefore, the orchard could use Ethiodemethrin 2.5% EC at 20 ml tree-1 and Karate 5% EC at 0.72 ml tree-1 for the control of leafminer. Moreover, using single control tactics does not provide utmost control of CLM in the orchard.

Open Access Original Research Article

Strategies for Increasing the Apple Epidermis Red Colored with Physiogrow® Color

Gentil Carneiro Gabardo, Lucas Pessoa de Freitas, Rafael Hermenegildo Contini, Eder Farina, Keli Cristina dos Santos, Verônica Niara de Souza, Ligia de Lara Furtado

Journal of Experimental Agriculture International, Page 1-7
DOI: 10.9734/jeai/2019/v34i330175

Aims: Evaluate different dosages and number of applications of the commercial product Physiogrow® Color on the percentage of red coloration of the epidermis, productivity and fruit quality in 'Royal Gala' apple trees, in the Midwest region of the state of Santa Catarina, Brazil.

Study Design: The experiment was arranged in a randomized block design with five replications. Place and Duration of Study: The experiment was carried out in the municipality of Fraiburgo-SC, Brazil (latitude 27º01'S, longitude 50º77’ W, altitude 950 meters), during the growing seasons of 2017/2018 and 2018/2019.

Methodology: The treatments  were: Control (No application), Physiogrow® color (4, 8 and 12 L ha-1) 7 days before harvest (DBH), Physiogrow® Color 2 L ha-1 (30 DAC) + 2 L ha-17 DBH, Physiogrow® Color 4 L ha-1 (30 DBH) + 4 L ha-17 DBH, and Physiogrow® Color 6 L ha-1 (30 DBH) + 6 L ha-1 7 DBH. The variables evaluated were: Production (kg plant-1 and fruits plant-1), average fresh fruit mass (g), classification of fruits by percentage of red coloration of the epidermis (<50%, 50-80% and > 80%), firmness of the pulp (lb in-2) and soluble solids (°Brix). The harvest was carried out on January 25, 2018 and February 16, 2019, first and second year, respectively. Plant production, as well as pulp firmness of fruits, were not affected by treatments, in both years. Physiogrow® Color promoted better distribution of fruits in categories of greater red coloration of the epidermis and reduction of the percentage of fruits in the category with coloration inferior to 50%, although a different behavior among the harvests was observed. The application of Physiogrow® Color 8 L ha-1 7 DBH contributes to the improvement of the coloration of ‘Royal Gala’ apples.

Open Access Original Research Article

Soil Nitrogen Contents as Affected by Composts Enriched with Organic Nitrogen Sources

F. O. Fawole, O. J. Ayodele, G. O. Adeoye

Journal of Experimental Agriculture International, Page 1-11
DOI: 10.9734/jeai/2019/v34i330177

Information is scanty on the potentials of agricultural wastes to enrich composts whose low nitrogen (N) content limits their use in organic farming. This study involved enriching composts - cow dung + sawdust (CDSD) and poultry droppings + sawdust (PDSD) with N from bone, blood, hoof and horn meals; and neem leaf and tithonia leaf meals and their incubation in the soil for 16 weeks. Cow dung and sawdust (CDSD), poultry manure and sawdust (PMSD) in 1:1 ratios were composted in separate heaps and samples taken for nutrient analysis at 2 and 22 weeks of composting. The composts were enriched with Bone, Blood, Hoof and Horn of cattle; Neem leaf and Tithonia leaf meals to obtain the following: CDSD + bone (CDSDBN), CDSD + blood (CDSDBM), CDSD + hoof (CDSDHM), CDSD + horn (CDSDHN), CDSD + neem (CDSDNM) and CDSD + tithonia (CDSDTM); PMSD + bone (PMSDBN), PMSD + blood (PMSDBM), PMSD + hoof (PMSDHM), PMSD + horn (PMSDHN), PMSD + neem (PMSDNM) and PMSD + tithonia (PMSDTM). The enrichment was madeto attain 100, 200, 300 and 500g kg-1 N. Each treatment at 30 t ha-1 was incubated for sixteen weeks to monitor the nutrient release at four-week intervals. Total N contents monitored at four-week intervals of incubation showed enrichment in 74.0 and 83.0% of CDSD and PDSD compared to the respective controls. N contents were highest in 21, 0, 1 and 28 composts incubated for 4, 8, 12 and 16 weeks respectively. At 4 weeks, CDSD enriched to 500 g kg-1 N from blood meal (CDSDBM) and bone meal (CDSDBN) contained 10.5 and 9.2 gkg-1 total N while PDSD enriched to 50 g kg-1 N from bone meal (PDSDBN) and tithonia leaf meal (PDSDTM) contained 9.3 and 8.6 g kg-1 total N. These are suitable for the cultivation of short-season leaf vegetables. N content reduced at 8 weeks of incubation and increased at 12 and 16 weeks. Only CDSD enriched with neem leaf meal (CDSDNM at all N rates) showed increase in N content with time of incubation. CDSDNM and PDSDBM at 50 g kg-1 N contained the highest total N at 16 weeks of incubation and should be recommended for the cultivation of long-season vegetables.