Increasing Irrigation Frequency Research Articles

Effect of Seasons and Irrigation Regimes on Plant Growth and Water-Use of Container-Grown Photinia × fraseri

Abstract Water-use and plant growth of Fraser photinia (Photinia × fraseri Dress) were studied under varying irrigation regimes during 2 different growing seasons, winter and summer. Rooted cuttings were transplanted into 7.57 1 (2 gal) plastic containers containing Metro-mix 500 and greenhouse-grown under 2 irrigation frequencies (3.5 or 7-day intervals) and 3 replacement amounts (100%, 75% or 50% replacement of actual water-use). Increased irrigation frequency significantly reduced plant growth parameters of winter-grown plants, including shoot growth, leaf number, leaf area and shot dry weight. Decreased irrigation amount significantly increased root dry weight. Significant differences were not detected in growth measurements of summer-grown plants suggesting differences between experiments are seasonal in nature. Frequent irrigation resulted in poor plant pelformance under winter growing conditions of lower evapotranspiration (ET); however under summer growing conditions, frequent irrigation did not significantly affect plant growth. Decreased irrigation frequency significantly increased total water-use for winter-grown plants due to increased plant performance. No significant differences in water-use due to frequency in summer-grown plants was found.

Evapotranspiration, Water Use Efficiency, Moisture Extraction Pattern and Plant Water Relations of Rape (Brassica campestris) Genotypes in Relation to Root Development under Varying Irrigation Schedules

SUMMARYA field experiment was conducted on sandy loam soil at Hisar, India during the autumn seasons 1984–85 and 1985–86 to study root characters, evapotranspiration, water use efficiency, moisture extraction pattern and plant water relations of rape genotypes under varying irrigation schedules. Root volume and dry weight increased, while tap root and lateral root lengths decreased with irrigation. Increased irrigation frequency increased evapotranspiration but decreased water use efficiency. The relative water content and osmotic potential of the leaves increased with more frequent irrigation, but plant water retention capacity decreased. There were genotypic differences between the characters examined.

Nitrogen and potassium requirement of pineapple in relation to irrigation in Nigeria

The investigation studied the effect of fertilization with four nitrogen levels (0, 100, 150 and 200 kg/ha), four potassium levels (0, 100, 150 and 200 kg/ha) and four irrigation treatments (0, 3, 7 and 14-day interval) on the growth and yield of smooth Cayenne pineapples. Increasing irrigation frequency increased growth parameters of number of leaves, D-leaf length and days to 50% flowering. Fruit weight was highest at N = 150 kg/ha, K = 200 kg/ ha and irrigation once a week. Higher N levels (beyond 150 kg/ha) applied after the plant crop has been harvested did not further enhance yields of the ratoon crop. For K = 200 kg/ha potential and harvested yields were reduced in all irrigation treatments when N > 150 kg/ha.

Factors affecting yield and quality in irrigated wheat

SummaryTwo field experiments examined the effects of nitrogen fertilizer, irrigation frequency and three wheat varieties on the yield and quality of irrigated wheat on a heavy clay soil. In the first experiment, with irrigation supplied to all plots at mid-tillering and close to ear emergence, there were negative effects of nitrogen fertilizer on grain yield with the reverse occurring with grain protein. The variety Songlen had one of the highest grain yields combined with higher milling yields and flour protein. In the second experiment, yield was maximized with at least two irrigations, whilst increasing irrigation frequency reduced flour protein and dough development time. While WW15 gave the highest yields irrespective of nitrogen or irrigation treatments, this variety had the lowest flour protein. With only one irrigation or without irrigation, nitrogen fertilizer increased grain protein; more frequent irrigation reduced mean flour protein.

Water Management of Greenhouse Tomatoes

Abstract Crack-susceptible and crack-resistant tomato (Lycopersicon esculentum L. Mill.) cultivars were grown in soil beds and in bags filled with a peat-vermiculite mix. Plants in soil were drip-irrigated 1 or 4 times daily, or hand-watered every day or as needed based on soil moisture tension. Plants in bags received only drip-irrigation treatments. Genotype had the greatest effect on fruit cracking, with 3.8% by weight cracked fruit in the crack-resistant compared to 35.3% in the crack-susceptible cultivar. Growing plants in bags reduced the weight and the percentage of cracked fruit per plant, but, in both cultivars, total and No. 1 fruit weights were greatest from the soil treatments with drip-irrigation. Irrigation frequency and method did not affect fruit weight except in the crack-resistant cultivar grown in bags where increasing irrigation frequency increased weights. Cracking was decreased by 22% in tomatoes irrigated manually every day, compared to those irrigated only when needed. In the soil treatment, raising the irrigation frequency significantly decreased cracking in the susceptible, but not in the resistant cultivar. In the soilless treatment, frequent irrigation increased cracking in both cultivars.

The Fate of Diazinon Applied to Thatched Turf1

AbstractDiazinon [0,0‐diethyl‐0‐(2‐isopropyl‐6‐methyl‐4‐primidinyl) phosphorothioate] is widely used to control turfgrass insect pests. Poor control of soil‐inhabiting insects has been found where diazinon has been applied to thatched turfgrass stands. The purpose of this study was to evaluate the environmental fate of diazinon applied to turfgrass stands. A microecosystem was used to follow the fate of radiolabeled diazinon surface applied to Kentucky bluegrass (Poa pratensis L.) turfs, with or without a thatch layer, growing on Flanigan silt loam (fine, montmorillonitic, mesic Aquic Argiudoll) irrigated daily or every 4 days. Loss of diazinon by volatilization, leaching, and degradation accompanied by release of 14CO2 or incorporation of label into soil compounds was measured. The most degradation of parent compound occurred on turf containing a thatch layer irrigated daily where only 7% of the applied diazinon remained after 3 weeks. Between 32 and 47% of the parent compound remained in either turf with thatch irrigated every 4 days or turfs without thatch. The majority of the diazinon (96%) remained in the top 10 mm of the turf profile regardless of whether this was thatch or soil. In the presence of thatch, there was an accelerated rate of diazinon degradation as measured by release of 14CO2 from the two position on the pyrmidine ring. Increasing irrigation frequency on the thatched turf did not cause an increase in leaching but did increase diazinon breakdown. The results of the study suggest that where thatch is present, reduced control of insects is due both to a failure of the insecticide to move through the thatch and an increased rate of degradation.

THE NITROGEN FACTOR IN THE MANAGEMENT OF EFFLUENT-IRRIGATED SOILS

ABSTRACT Reuse of treated sewage effluents in agriculture is attracting much attention in Israel, not only as a useful means for preventing environmental pollution, but also as an important source of water for irrigation. Despite great differences in their sensitivity to available-N concentration, three different crops responded positively to modifications in a regular irrigation-fertilization regime. Increasing irrigation frequency increased N-uptake by Rhodes grass (Chloris gayana Kunth.), while increasing irrigation intervals in sugar beet restored sugar percentage that had dropped sharply after other irrigation treatments. Effluent irrigation replaced N-fertilization, resulting in a yield increase in cotton despite a small decline in lint percentage. A large savings of N-fertilizer was possible in all cases, and the hazards of nitrate leaching below the root zone were apparently diminished. The results indicate that adjusted management in an important tool for the control of nitrogen in effluent-irrigated fields. A similar approach may be useful also for the other components of partially treated wastewater some of which may involve long-term effects.

Irrigation frequency and total water application with trickle and furrow systems

One of the main attributes of trickle irrigation is that it enables the available water to be utilised as efficiently as possible. This is achieved through the elimination of waste that is an inevitable consequence of normal irrigation practice.The water requirements of crops can be calculated to a reasonable degree of accuracy using formulae that have been developed to relate evapotranspiration to the evaporation from a U.S. Class A pan evaporimeter, with suitable adjustments for the particular crop and the degree of ground cover.The aims of the experiments described in this paper were: 1.(1) to compare the yield of field tomatoes under trickle irrigation and furrow irrigation over a range of irrigation frequencies and amounts that can reasonably be used for both methods;2.(2) to compare the effects of irrigation frequency over a range of irrigation amounts that are typical for each irrigation method;3.(3) to compare the effects of irrigation amounts over a range of irrigation frequencies that are typical for each irrigation method;4.(4) to examine the interaction, if any, between irrigation frequency and amount.The results of the trial showed that there was no difference in yield between trickle irrigation and furrow irrigation over a range of conditions for which they could legitimately be compared. At the same time it should be realized that the results for furrow irrigation on small plots may not adequately represent the normal farm practice for this method, where less efficient watering occurs due to long runs and unavoidable inequalities in water application.For both irrigation methods there was a consistent trend of decreasing yields with increasing irrigation frequency. Where departures from this trend occurred in unusual irrigation conditions (i.e. continuous irrigation and prolonged drought) the effect is explained by physiological causes that relate to the particular conditions. In such cases only, there was an interaction between irrigation frequency and amount.For each irrigation frequency the highest yields were obtained for the optimum amounts as calculated to match the potential evapotranspiration rate. Equal amounts of under-watering and over-watering resulted in approximately the same reductions in yields.The results from the trial indicate that the highest yields and greatest efficiency of water use occur at frequent intervals with an amount of applied water approximately equal to that calculated from simple formulae relating evapotranspiration to measured pan evaporation. Extrapolation of the results of particular trials to other crops, soils and climates should be treated with caution. However, the agreement of the results with those predicted from physiological and empirical data, and the fact that the results from other experiments also agree with such formulae, give cause for confidence in predicting the responses to irrigation timing and amounts over a wide range of conditions.

Principles of Managing High Frequency Irrigation

AbstractThe consequences of increasing irrigation frequency are explored, taking into consideration the laws governing water flow in soil. As frequency increases, the waterholding capacity of the soil becomes less important because water is supplied as the plants require it. Soil water content, and therefore matric potential, are continuously high and only slightly dependent upon deep percolation rate. This makes the need for deep percolation to leach salts the only valid criterion for applying more water than the plants transpire. The need to apply extra water to those crops that require high soil water content is eliminated. Controlling the deep percolation rate rather than the soil water status requires measurements of flux rather than water potential as inputs for managing the quantity of water to be applied.

Effect of irrigation frequency and fungicide spray on yield and disease infection of onion

A two-year field experiment was conducted at Regional Agricultural Research Station, Jessore during the rabi seasons of 2002-2003 and 2003-2004 to find out the level of disease incidence under different levels of irrigation and fungicide spray on the bulb yield of onion. Four irrigation levels: no irrigation (I1), irrigation at 10 days interval (I2), 20 days interval (I3), and 30 days interval (14) with 4 spray schedules: no spray (F1), one spray at 40 days after transplanting (DAT) (F2), two sprays each at 40 and 55 DAT (F3) and three sprays each at 40, 55, and 70 DAT (F4) were used. Yield and yield attributes varied significantly (p = 0.05) between sprayed and unsprayed, and irrigated and non-irrigated treatments, respectively. Higher yields were obtained with the higher frequencies of irrigation and spray. Application of fungicide reduced the disease severity significantly, while irrigation had no significant effect on disease infection. But there was a decreasing trend of the disease severity with increasing irrigation frequency. The highest bulb yield of onion (12.45 t/ha) was obtained with a total water use of 245 mm in six applications including an effective rainfall of 16 mm and three sprays. The disease severity between sprayed and unsprayed plots ranged from 1.33 to 3.16 for I1, 1.08 to 2.33 for I2 1.16 to 2.83 for I3, and 1.16 to 3.00 for I4, respectively. Key Words: Onion, disease incidence, irrigation, water use efficiency. DOI: 10.3329/bjar.v34i3.3967 Bangladesh J. Agril. Res. 34(3) : 417-424, September 2009