Potassium Fertigation Research Articles

Effect of Potassium Fertigation Levels on Jalapeno Pepper Growth in Red Bole Soil under Polyhouse Conditions

A field experiment was conducted at Instructional Farm Polyhouse, Dr. Sharadchandra Pawar College of Agriculture, Baramati during June 2023 to September 2023. The study aimed to investigate the Influence of Graded levels of Potassium Fertigation on Growth of Jalapeno Pepper Grown in Red Bole Soil Under Polyhouse. The experiment was laid out in Randomized Block Design (RBD) with four replications. The treatments were five, viz., T1- Control, T2- Recommended dose of fertilizer, T3- Recommended dose of nitrogen and phosphorus (RDNP) + 125% Recommended dose of potassium (RDK), T4- Recommended dose of nitrogen and phosphorus (RDNP) + 150% Recommended dose of potassium (RDK) and T5- Recommended dose of nitrogen and phosphorus (RDNP) + 175% Recommended dose of potassium (RDK). Data were taken on growth contributing characters and the collected data were statistically analyzed for evaluation of the treatment effects. Data on growth parameters, including plant height, leaf area and chlorophyll content, were recorded at 20, 35, 50 and 65 days after transplanting (DAT) and analyzed statistically. The results indicated that the maximum plant height (95.65 cm), leaf area (61.61 dm²) and chlorophyll content (58.83) at 65 DAT were significantly higher in treatment T5 (RDNP + 175% RDK). This study concludes that the application of RDNP + 175% RDK via fertigation from 10 DAT to 60 DAT is optimal for the growth of Jalapeno pepper in red bole soil under polyhouse conditions, highlighting its potential for improving crop yield and quality.

Potassium fertigation and organic fertilisation in ‘Syrah’ grape in Northeastern Brazil: yield, must characteristics and phenolic compounds

The effect of both potassium and organic fertilisation on grape yield and must composition originating from wine grapevines cultivated in the São Francisco river basin, in the semi-arid region of Northeastern Brazil, is not well known. Since soils from that region usually have low organic matter content, we hypothesise that soil application of organic fertiliser and potassium application through drip irrigation enhances the availability of this nutrient in the soil, and it influences grape yield and quality. Hence, five doses of potassium (0, 20, 40, 80 and 160 kg ha-1) applied through a drip irrigation system and two doses of goat manure as organic fertiliser applied into the soil (0 and 7.5 m3 ha-1) after pruning were evaluated concerning yield and berry quality of grapevine ‘Syrah’ over four growing seasons (April 2013 to July 2015) in Petrolina, state of Pernambuco, Brazil. The experimental design was randomised blocks with 5 replications. We evaluated yield (t ha-1), weight of 100 berries (g), must volume (mL), total soluble solids (°Brix), pH and total titratable acidity (‰), K, Mg and Ca contents and phenolic compounds (total polyphenols, anthocyanins and flavonoids). The increasing application of potassium at the different doses of organic fertiliser did not alter the crop yield, except in the second season. Nonetheless, K concentration in grape must was influenced in the four growing seasons, with higher values at fitted K2O doses by polynomial regression of 83.62 kg ha-1 (first season), 101.25 kg ha-1 (second season), 120.00 kg ha-1 (third season) and 77.99 kg ha-1 (0 m3 ha-1 organic fertiliser) and 96.07 kg ha-1 (7.5 m3 ha-1 organic fertiliser) in the fourth season. The addition of increasing doses of potassium interfered with the wine grape quality, which is an important factor to be considered in relation to its acidity. Organic fertilisation did not affect the most quality characteristics of the grapes.

Micro-nano bubble water with potassium fertigation improves strawberry yield and quality by changing soil bacterial community

Aerated drip irrigation can increase the soil oxygen content and improve the utilization efficiency of fertilizer. However, limited information is available on how soluble potassium fertilizer with different aeration levels affects plant yield and quality. Specifically, the underlying mechanism associated with microbial community level has not been reported so far. In this study, a micro-nano bubble water (MNBW) drip irrigation experiment was conducted in a strawberry plantation greenhouse, with three ratios of MNBW and two potassium application amounts and a control treatment (without MNBW). The results showed that compared with the CK (no aeration, 100% traditional potassium fertilizer application, 144 kg hm−2 of potassium sulfate), MNBW irrigation improved the soil oxygen content and changed the structure and functionality of the soil microbial community in the strawberry rhizosphere. The bacterial diversity was reduced, and the microbial co-occurrence patterns were altered. The soil respiration intensity increased by 1.32%–14.22%. The soil temperature increased, and the decomposition of organic matter was enhanced. It was indicated that the increase of soil oxygen had a positive impact on soil fertility, strawberry yield, and quality under the condition of reducing potassium application. The yield and quality of strawberries in MNBW treatments were significantly higher than those treated with CK (p < 0.05), but the carbon dioxide emissions significantly increased. High potassium fertilizer application amount and MNBW ratio did not mean high yield and quality of strawberries. Thus, O20K70 (20% of irrigation water with micro-nano bubbles, 70% of traditional drip irrigation potassium fertilizer level, 101 kg hm−2 of potassium sulfate) and O60K70 (60% of irrigation water with micro-nano bubbles, 70% of traditional drip irrigation potassium fertilizer level, 101 kg hm−2 of potassium sulfate) could be chosen for strawberry plantations with MNBW.

Redução do estresse salino em quiabeiro sob fertirrigação potássica

ABSTRACT Potassium fertigation may be a strategy to reduce saline stress in okra. The objective of this study was to analyze the effect of potassium supplementation as a salinity-attenuating agent in okra. The experiment was conducted in a greenhouse at the Federal Rural University of the Semi-Arid Region, in Mossoró-RN, Brazil. The experimental design was completely randomized, in 2x5 factorial scheme with 4 replicates. Two okra cultivars (Santa Cruz 47 and Valença) fertigated with five fertigation managements [F1= irrigation with non-saline water (0.55 dS/m) and fertigation with a standard dose of potassium (6 g/plant); F2= irrigation with saline water (3.5 dS/m) and fertigation with 6 g/plant of K, F3= irrigation with saline water (3.5 dS/m) and fertigation with 9 g/plant of K, F4= irrigation with saline water (3.5 dS/m) and fertigation with 12 g/plant of K, and F5= irrigation with saline water (3.5 dS/m) and fertigation with 15 g/plant of K]. Plants were collected 110 days after emergence and evaluated for growth variables (leaf number, leaf area, leaf dry mass, stem dry mass, total dry mass) and yield (fruit number, average fruit mass and fruit production). Potassium influenced the growth and yield characteristics of okra irrigated with saline water. The highest yields of fruits occurred at 9.56 and 10.23 g/plant of K, being 330.24 and 733.36 g/plant obtained from cultivars Santa Cruz 47 and Valença, respectively. Okra irrigated with saline water is more demanding in potassium.

Potassium Fertigation Improved Growth, Yield and Quality of Kinnow Mandarin in Potassium Rich Soils

ABSTRACT Effects of potassium fertigation on the productivity of Kinnow were investigated in potassium rich soils of South-Western Punjab, India during 2018–2020. Three application rates of potassium i.e. 1000, 750 and 500 g Muriate of Potash (MoP; 60% K as K2O) per tree were applied at fortnightly intervals in two, three and four splits during February, May, July and September. The results were compared with standard recommendation for the region (three foliar sprays of 1% potassium nitrate) and no K application (control). The experiment was laid out in randomized block design, replicated thrice. The data showed that K fertigation significantly (p < .05) improved the growth, yield and quality of fruits over both standard recommendation and control. A comparison among different K split applications (fertigation) revealed higher growth, yield and quality of fruits in trees which received MoP in four splits. However, the differences among 1000 g, 750 g and 500 g K application rates were statistically comparable especially in terms of tree vigor, yield, percent juice, TSS–acid ratio and ascorbic acid content of fruits. These results suggest the fertigation of 500 g MoP per tree in four split applications to achieve higher growth and productivity of Kinnow in K rich soils of South-Western Punjab.

Effect of Nitrogen and Potassium Fertigation Schedules on Plant Growth Parameters and Fertilizer Use Efficiency of Sunflower

A field experiment was conducted at Water Technology Centre, College farm, Rajendranagar, Hyderabad with sunflower (variety DRSH-1) during rabi 2017-18 in a randomized block design with three replications and the treatments were nine with combinations of N (75 kg ha-1) and K (30 kg ha-1) fertilizers applied by fertigation through ventury at different intervals viz., 3 days and 4 days. Drip irrigation was scheduled once in 2 days at 0.8 E pan. Fertigation was imposed at 16 DAS to 88 DAS and completed in 19 and 10 splits in 4 and 8 days interval respectively. The source of N and K fertilizers was urea and potassium sulphate respectively. The soil was sandy clay loam in texture, alkaline in reaction, non saline, low in available nitrogen, medium in available phosphorus and potassium. The amount of total irrigation water applied was 3188 m3 and 4666 m3 in drip irrigation and furrow irrigation treatments, respectively. The N and K fertigation (75-30 kg N-K2O ha-1) at 4 days interval has recorded relatively higher plant growth parameters like number of leaves plant-1 (25.5), plant height (208 cm), SPAD Chlorophyll Meter Reading (55.7), leaf area index (3.5) and dry matter (158.1 g m-2) which were on par with N and K at 8 days interval.&#x0D; Higher N-FUE (12.8 kg seed yield / nutrient applied) and K-FUE (25.6 kg seed yield / kg nutrient applied) was recorded in application of N+K at 4 days interval.

Effect of Different N and K Fertigation Levels of Capsicum (Capsicum annuum var. grossum L.) as Influenced by Nutrient Content of Capsicum under Poly House

The experiment was carried out during rabi season of 2018-19 at Water Technology Centre, College of Agriculture, Rajendranagar, Hyderabad on capsicum (Capsicum annuum var. grossum L.) with respect to different nitrogen and potassium fertigation levels under poly house. The experiment comprised of three replications in Factorial Randomized Block Design (FRBD) with two factors {i.e. N levels (4), K levels (3) } and twelve treatments Viz; N fertigation levels of 0 %, 120 % (216 kg N ha-1) , 150 % (270 kg N ha-1), 180 % (324 kg N ha-1) and K fertigation levels of 0 %, 80 % (96 kg K2O ha-1), 100% (120 kg K2O ha-1) respectively. The 100 % RDF was 180, 90 and 120 kg N, P2O5 and K2O ha-1. The source of N was urea, P was single super phosphate (SSP) and K was white muriate of potash (MOP). The N and K were applied through drip fertigation on every fourth day during different crop growth stages. In the fertigation programme, during crop establishment stage (10 DAT to 14 DAT), 10 % of N and K2O were applied in two splits. During vegetative stage, (15 to 46 DAT) 30 % of N and 20 % of K2O were applied in eight splits. During flower initiation to fruit development (47 DAT to 74 DAT) 20 % of N and K2O were applied in seven splits. From fruit development till final harvesting stage (75 DAT to 154 DAT) 40 % of N and 50 % K2O were applied in 20 splits in a total of 37 splits. The soil of the experimental site was sandy loam in texture with low in available nitrogen (166.5 kg ha-1), medium in available phosphorus (81.1 kg P2O5 ha-1) and low in available potassium (245.4 kg K2O ha-1). Irrigation was scheduled at 0.8 Epan based on pan evaporation data. The total water applied to the crop was 414.8 mm. The total nitrogen content in capsicum shoots ranged from 3.41 to 4.57 %, 4.29 to 6.35 %, 4.43 to 6.67%, 4.76 to 6.86% and 4.53 to 6.58% at 30, 60, 90, and 120 and at final harvest respectively. In fruits, it ranged from 4.11 to 6.49 %, 3.92 to 6.35%, 4.01 to 6.25 % at 90, 120 and at final harvest respectively. The total phosphorus content in capsicum shoots ranged from 0.13 to 0.23 %, 0.42 to 0.92%, 0.14 to 0.33%, 0.12 to 0.24% and 0.12 to 0.20% at 30, 60, 90, 120 and at final harvest respectively. In fruits it ranged from 0.20 to 0.59 %, 0.24 to 0.57 %, 0.26 to 0.70 % at 90, 120 and at final harvest respectively. The total potassium content in capsicum shoots ranged from 0.87 to 1.83 %, 1.77 to 2.65%, 1.50 to 2.23%, 0.96 to 1.54% and 0.83 to 1.38% at 30, 60, 90, 120 and at final harvest respectively. In fruits it ranged from 1.02 to 1.47%, 0.98 to 1.35%, 0.93 to 1.28% at 90, 120 and at final harvest respectively.

Tef (Eragrostis tef) Responses to Phosphorus and Potassium Fertigation under Semi-Arid Mediterranean Climate

Tef (Eragrostis tef (Zucc.) Trotter) is an annual small grain, panicle bearing, C4 cereal crop native to Ethiopia, where it is a major staple food. The objectives of the present study were to characterize the responses of two tef genotypes to escalating phosphorus (P) and potassium (K) levels and to determine an optimum range for P and K at which tef performance is maximized. Two experiments were carried out in the Gilat Research Station, each testing two different genotypes of tef (405B and 406W), one experiment in pots in controlled conditions, and the other in the field. In both experiments, the highest grain yield increased until 6 mg L−1 P, and declined at 12 mg L−1 P. The decline was precipitous and significant in the pot experiment, and gradual and statistically insignificant in the field experiment. In the pots experiment, the grain yield increased until 40 mg L−1 K, with no significant decrease thereafter. The effect of K concentration was only seen in the grain yield and not in the size of the other plant organs. In the field experiment, grain yield was highest at 80 mg L−1 K, but it was not statistically different from 40 mg L−1. The effect of K on growth was only apparent at maturity and not at flowering.

Effect of Potassium Foliar Application and Fertigation on Biological Aspects and Plant Growth Biomass of PepperP (capsicum annuum). تأثير الرسمدة والرش الورقي للبوتاسيوم علي المکونات الحيوية والکتلة الحيوية للنبات الفلفل.

Two field experiments were carried out at a private farm, Damietta, Egypt to study the effect of foliar application and fertigation on the biological aspects as (plant height, number of leaves and root length and plant growth biomass (i.e., fresh and dry and shoot/root ratio and relative growth rate) as well as chlorophyll contents of pepper. Four foliar potassium treatments ((K0 (control), K1; 2kg fed-1 , K2; 4kg fed-1, and K3; 6kg fed-1) ) combined with three fertigation treatments (K0 (control), K1; 66kg fed-1 K2; 132kg fed-1) were arranged in a split-plot design with three replicates. The results showed that plant height and root length increased significantly by potassium fertigation and foliar application compared to the control. In contrast, potassium fertigation and foliar application had no significant effect on leaf area and leaf area index in both seasons. Pepper fresh and dry weights decreased by increasing K fertigation compared to the control, while potassium foliar application (K-leaf) significantly increased pepper fresh and dry weights with increasing potassium compared to the control except with the treatment of 6 kg fed-1 in both seasons. Potassium fertigation and foliar application had no significant effect on chlorophyll A, B, total carbohydrates and total phenols. While vitamin C increased by increasing potassium fertigation. The treatment of 50% in the recommended dose recorded the highest vitamin C values in both seasons and the potassium foliar application with K- leaf at the rate of 4 kg k fed-1 gave the highest vitamin C values in both seasons.

Red-Green-Blue and Multispectral Imaging as Potential Tools for Estimating Growth and Nutritional Performance of Cassava under Deficit Irrigation and Potassium Fertigation

Cassava has high energy value and rich nutritional content, yet its productivity in the tropics is seriously constrained by abiotic stresses such as water deficit and low potassium (K) nutrition. Systems that allow evaluation of genotypes in the field and greenhouse for nondestructive estimation of plant performance would be useful means for monitoring the health of plants for crop-management decisions. We investigated whether the red–green–blue (RGB) and multispectral images could be used to detect the previsual effects of water deficit and low K in cassava, and whether the crop quality changes due to low moisture and low K could be observed from the images. Pot experiments were conducted with cassava cuttings. The experimental design was a split-plot arranged in a completely randomized design. Treatments were three irrigation doses split into various K rates. Plant images were captured beginning 30 days after planting (DAP) and ended at 90 DAP when plants were harvested. Results show that biomass, chlorophyll, and net photosynthesis were estimated with the highest accuracy (R2 = 0.90), followed by leaf area (R2 = 0.76). Starch, energy, carotenoid, and cyanide were also estimated satisfactorily (R2 &gt; 0.80), although cyanide showed negative regression coefficients. All mineral elements showed lower estimation accuracy (R2 = 0.14–0.48) and exhibited weak associations with the spectral indices. Use of the normalized difference vegetation index (NDVI), green area (GA), and simple ratio (SR) indices allowed better estimation of growth and key nutritional traits. Irrigation dose 30% of pot capacity enriched with 0.01 mM K reduced most index values but increased the crop senescence index (CSI). Increasing K to 16 mM over the irrigation doses resulted in high index values, but low CSI. The findings indicate that RGB and multispectral imaging can provide indirect measurements of growth and key nutritional traits in cassava. Hence, they can be used as a tool in various breeding programs to facilitate cultivar evaluation and support management decisions to avert stress, such as the decision to irrigate or apply fertilizers.

Potassium Fertigation With Deficit Irrigation Improves the Nutritive Quality of Cassava

Water deficit limits cassava (Manihot esculenta Crantz) productivity in drought-prone areas and alters the nutritive quality of the crop. Potassium (K) may mitigate the effects of water deficit and improve the nutritional content of cassava, which would alleviate malnutrition among the human population in the tropics who depend on cassava as a staple food. Pot experiments were conducted under controlled glasshouse conditions to investigate the influence of deficit irrigation and K fertigation on the nutritive and anti-nutritive quality of biofortified cassava during the early growth phase. Treatments initiated at 30 days after planting were three irrigation doses (30%, 60%, 100% pot capacity) that were split to five K (0.01, 1, 4, 16 and 32 mM) concentrations. Plants were harvested at 90 days after planting, and the starch, energy, carotenoid, crude protein, fiber, minerals and cyanide concentration of the leaves and roots were determined. Irrigation and K treatments showed significant (P < 0.05) interactions for starch, carotenoid, energy and cyanide concentration. An irrigation dose of 30% together with 0.01 mM K resulted in the lowest starch, carotenoid, energy, and fiber content, but highest cyanide concentration, relative to full-irrigated (100%) plants together with 16 mM K. When the K application rate was 16 mM the best nutritional quality was obtained, with the lowest cyanide concentration, regardless of irrigation dose. Moreover, nutritional traits showed strong positive associations, whereas cyanide concentration correlated negatively with all the nutritional traits. Notably, an irrigation dose of 60% together with 16 mM K reduced the nutritional content the least and showed minimal increase in cyanide concentration. The results indicate that K fertigation with adjusted irrigation may improve the dietary quality of young cassava and reduce antinutrients, which could enhance the nutrient bioavailability of cassava grown in drought-prone areas.

Correction of Potassium Fertigation Rate of Apple Tree (Malus domestica Borkh.) in Central Russia during the Growing Season.

The proper use of potassium fertilizer can stimulate a significant yield increase. However, the application of excessively high rates of potassium can reduce the availability of soil calcium for apple trees. The potassium fertigation rate must meet the apple tree’s requirements so that the applied fertilizers can be absorbed by the roots as much as possible. Crop load in apple orchards sometimes varies significantly in different years. The potassium content in apple fruits is relatively high, and the maximum requirement for this nutrient occurs when fruits grow and ripen. Different crop loads at that time mean the various demands of trees and need for changing application rates for this nutrient. The investigation was carried out in the experimental orchard of I.V. Michurin Federal Scientific Centre (Michurinsk, Russia) in 2016 and 2017 (52.885131, 40.465613). We studied seasonal changes of potassium and calcium contents in soil, fruits, and leaves and their relationship with yield during the research. We paid much attention to the potassium rate shift on its content in leaves and fruits and cultivars “Lobo” and “Zhigulevskoye” yield. If the potassium application rate changes according to the actual crop load, it stimulates the yield growth or (if the crop load was relatively low) the reduction of the rate did not lower the productivity. Moreover, we studied the relationship between potassium and calcium nutrition. The decrease in potassium fertigation rate increased the availability of soil calcium. It was the reason for fruit calcium concentration enlargement and mitigation of the K/Ca ratio. We also specified some parameters for soil–leaf diagnosis for potassium nutrition during the growing season.

Wheat Production Functions Under Irrigated Saline Environment and Foliar Potassium Fertigation

Wheat Production Functions Under Irrigated Saline Environment and Foliar Potassium Fertigation

Growth, yield and chemical composition of eggplant ‘Ciça’ under potassium fertigation

The objective of this work was to evaluate the effect of potassium concentrations applied via fertigation on the growth, yield and chemical composition of eggplant ‘Ciça’ in a distroferric red Latosol. The treatments were composed of five concentrations of K2O (0, 36, 72, 108 and 144 kg ha-1 supplied via fertigation), using potassium chloride as a source, divided into six applications. The irrigation system was of the drip type and irrigation management was done via a “Class A” evaporometer tank. Harvest started at 62 days after transplanting (DAT) and lasted for five months. The variables evaluated were: plant height, number of leaves, fresh fruit mass, number of fruits per plant, yield per plant, productivity and classification of the fruits according to their length and diameter. At 85 DAT, fruit were collected for characterization as to the percentage of lipids, proteins and fibers. Although the potassium fertigation in cover provided a reduction in the production and productivity, the concentrations of 36 kg ha-1 and 72 kg ha-1 of K2O applied via fertigation, increased the physical-chemical characteristics of the fruits.

Growth Response of Cassava to Deficit Irrigation and Potassium Fertigation during the Early Growth Phase

Cassava (Manihot esculenta Crantz) experiences intermittent water deficit and suffers from potassium (K) deficiency that seriously constrains its yield in the tropics. Currently, the interaction effect between deficit irrigation and K fertigation on growth and yield of cassava is unknown, especially during the early growth phase. Therefore, pot experiments were conducted under controlled greenhouse conditions using cassava cuttings. Treatments initiated at 30 days after planting included three irrigation doses (30%, 60%, 100% pot capacity) and five K (0.01, 1, 4, 16, and 32 mM) concentrations. The plants were harvested 90 days after planting. Decreasing irrigation dose to 30% together with 16 mM K lowered the leaf water potential by 69%, leaf osmotic potential by 41%, photosynthesis by 35%, stomatal conductance by 41%, water usage by 50%, leaf area by 17%, and whole-plant dry mass by 41%, compared with full-irrigated plants. Lowering the K concentration below 16 mM reduced the values further. Notably, growth and yield were decreased the least compared with optimal, when irrigation dose was decreased to 60% together with 16 mM K. The results demonstrate that deficit irrigation strategies could be utilized to develop management practices to improve cassava productivity by means of K fertigation under low moisture conditions.

Effect of nitrogen and potassium fertigation on growth, yield, quality and nutrient use efficiency of banana under subtropics

A field experiment was conducted during 2016–19 to standardize the fertilizer dose and scheduling for growth, yield and quality of banana under subtropical conditions at Research Farm of ICAR-Central Institute for Subtropical Horticulture, Rehmankhera, Lucknow. The highest mean pseudo stem girth (60.24 cm), leaf area (6.922 m2) and cumulative fruit yield (94.60 t/ha) were recorded in 100% recommended dose of fertilizer (RDF) of N and K applied (40:25, 30:35, 30:25, 0.15) at different phenological stages of growth. Whereas, maximum B:C ratio (2.10) and Total Soluble Solids (21.7 OB) was recorded in 80% RDF of N and K applied (40:25, 30:35, 30:25, 0.15) at different stages of growth. Where as, mean nutrient use efficiency ((41.40 tons fruit/tons nutrient) was recorded in 60% RDF of N and K applied (10:10, 40:20, 30:20, 20:40) at vegetative growth, pre-flowering, flowering and bunch development stage in banana cultivar Grand Naine under subtropical conditions.

Water productivity and economics of rabi sunflower as influenced by nitrogen and potassium fertigation schedules

Water productivity and economics of rabi sunflower as influenced by nitrogen and potassium fertigation schedules

Water productivity of wheat cultivars under saline irrigation and foliar potassium fertigation

Availability of fresh water is one of the limiting factors affecting the growth and yield of a variety of crops. Besides this, declining water table depths and deterioration of its quality is rampant in many parts of the world today. Salt-affected irrigated land in the world is increasing over the years. Sustaining crop growth and yield with proper management of irrigation water under saline environment necessitates modification in the conventional crop cultivation practices. A field experiment was conducted on two winter wheat (Triticum aestivum L.) cultivars (viz. salt tolerant cultivar KRL-1-4 and salt non-tolerant cultivar HD-2894) under saline irrigation regimes (1.7 to 12 dSm-1) with and without foliar potassium fertigation in the research farm of the Water Technology Center (WTC), ICAR-IARI, New Delhi, India. In this experiment potassium was applied in the ratio of K+: Na+ (1: 10) as foliar application during the heading stage of the crop. The KRL-1-4 cultivar under foliar treatment resulted in increase in water productivity by 6.3 to 21.1% as compared to the non-foliar treatments with irrigation water salinity ranging from 1.7 to 12 dSm-1. The increase in water productivity of wheat with foliar potassium fertigation over the non-foliar application for the HD 2894 cultivar was found to vary from 3.8 to 14.9% with irrigation water salinity upto 12 dSm-1. Overall, it was observed that the water productivity of both cultivars under foliar potassium fertigation resulted in higher water productivity for all salinity regimes as compared to the non-foliar treatment.

Potassium and Nitrogen Fertigation Frequency on Pineapple Yield and Fruit Quality

Pineapple is a nutritionally demanding crop, with emphasis on potassium and nitrogen nutrients. In this context, the aim of this paper was to study the effect of nitrogen (N) and potassium (K) fertigation frequencies on the physical-chemical fruit characteristics of &amp;lsquo;P&amp;eacute;rola&amp;rsquo; pineapple crop. The experiment was conducted in a randomized block design, with 18 treatments and 4 replications. It was used a factorial scheme (4 &amp;times; 4) + 1 + 1, which represents: four N fertigation frequencies applied by surface drip irrigation (4, 7, 27 and 54 times throughout the crop cycle); four K fertigation frequencies (4, 9, 35 and 70 times); one additional treatment (irrigated, but without fertigation); and one control (non irrigated and non fertigated). The fruit characteristics analyzed were: fruit mass with crown, yield, soluble solids, pH, titratable acidity and SS/TA ratio. The N fertigation frequencies had no effect on variables evaluated, however, the K frequencies had a significant influence on fruit mass with crown, yield and pH. The results showed that the effect of K frequencies applied through fertigation on pineapple yield and fruit physical-chemical quality was more pronounced in comparison to the effect of N applications. Monthly potassium fertigations, followed by four applications throughout the crop cycle, provided the greatest increase in fruit quality, allowing higher values of fruit mass, yield and pH.

Nitrogen and potassium fertigation in bell pepper cultivated in greenhouse using fertigation managements

ABSTRACT The objective of the study was to evaluate the effect of different managements of fertigation and NK doses on the production of bell pepper fruit in a protected environment. The experimental design was randomized blocks in 3 x 5 factorial. The treatments were formed by the combination of three managements of fertigation (M1 - Based on the rate of absorption; M2 - Monitoring the electrical conductivity of the soil solution; M3 - Monitoring concentrations of N and K ions in the soil solution), with five doses of NK (0, 50, 100, 150 and 200% of the recommended dose) and four replicates. Six samples were collected and the following variables were evaluated: number, length and diameter of fruit, pulp thickness and fruit production. Except for diameter, all variables were affected by the interaction between the studied factors. The fertigation management by monitoring and controlling the ionic concentration of the soil solution is more efficient in the production of bell pepper. The fertigation management can be performed more efficiently from the managements M2 or M3, with NK doses of 144 and 165%, respectively, of the recommended concentration for the hydroponic cultivation of bell pepper.