Crop Water Need Research Articles

Sensitivity of Crop Water Need to 2071–95 Projected Temperature and Precipitation Changes in Jamaica

Abstract This study uses empirical models to examine the potential impact of climate change, based on a range of 100-yr phase 5 of the Coupled Model Intercomparison Project (CMIP5) projections, on crop water need in Jamaica. As expected, crop water need increases with rising temperature and decreasing precipitation, especially in May–July. Comparing the temperature and precipitation impacts on crop water need indicates that the 25th percentile of CMIP5 temperature change (moderate warming) yields a larger crop water deficit than the 75th percentile of CMIP5 precipitation change (wet winter and dry summer), but the 25th percentile of CMIP5 precipitation change (substantial drying) dominates the 75th percentile of CMIP5 temperature change (extreme warming). Over the annual cycle, the warming contributes to larger crop water deficits from November to April, while the drying has a greater influence from May to October. All experiments decrease crop suitability, with the largest impact from March to August.

A MODERN APPROACH FOR FERTIGATION UNDER GATED PIPES TECHNIQUE AND ITS IMPACT ON MAIZE PRODUCTIVITY AT NORTH NILE DELTA

For improving nitrogen utilization efficiency by maize crop under gated pipes irrigation technique, a field experiment was conducted at El-Hamoul district, Kafr Elshiekh governorate during the summer season of 2011. The experiment included traditional furrow irrigation, gated pipes and alternative furrows irrigation by gated pipes technique, Two forms of mineral nitrogen fertilizers Urea (CO (NH2)2) and ammonium nitrate (NH4NO3) were applied at the recommended dose (135 Kg N Fed-1) either as soil dressing or through irrigation as compared with the control treatment (without nitrogen application), The main obtained results could be summarized as follows: Using gated pipes technique for irrigating maize crop resulted in less amount of water applied compared to traditional furrow irrigation method. On the other hand, gated pipes technique saved irrigation water by 19.74 and 30.77 % for gated pipe and alternative gated pipes techniques, respectively as compared with traditional furrowirrigation. This improved irrigation techniques led to decrease actual water consumptive use, improved water application efficiency and increased the contribution of ground water table in the crop water need. There was no effect on maize yield due to different irrigation techniques. However, gated pipes and alternative gated pipes recorded the highest values of grain yield (3.3 and 2.6 %) and stalk yield (47.6 and 15.1%) over the traditional furrow irrigation, respectively. Whereas, maize grain yield increased by about 62.1 , 59.7, 58.8 and 45.8 over control treatment due to application of ammonium nitrate applied by dressing method, urea applied withirrigation water, urea applied by dressing method and ammonium nitrate applied withirrigation water, respectively. Maize grain yield took the same trend of stalk yield. It can be observed that gated pipes technique for all furrows under ammonium nitrate applied by dressing method achieved the highest grain and stalk yields followed by treatment alternate furrows which irrigated by gated pipes under urea applied withirrigation water. The highest mean values of crop and field water use efficiencies were achieved under gated pipes alternative furrow techniques and Urea applied withirrigation water. Nitrogen use efficiency and N recovery % were increased with gated pipes irrigation techniques under ammonium nitrate applied by dressing method and urea applied withirrigation water Net income from water unit and economical efficiency increased with gated pipes techniques (for all furrow and alternative furrow) comparing with traditional furrow irrigation treatment.

Root system distribution of sugarcane irrigated with domestic sewage effluent aplication by subsurface drip system

Irrigation with domestic sewage effluent (DSE) has been recommended by subsurface dripping, as it can obtain a high rate of irrigation efficiency and faster use of salts in comparison with other irrigation methods. The study aimed at evaluating the area, the length and the effective depth of the root system of sugarcane irrigated with DSE by subsurface drip system and with different irrigation rates at depths of 0.00-0.20, 0.20-0.40, 0.40-0.60 and 0.60-0.80m. The experiment was carried out in the municipality of Piracicaba, in the state of São Paulo (SP), Brazil, in a sugarcane area irrigated with DSE in a completely randomized blocks set up in furrows, with three replications and four treatments, which are: one area without irrigation (AWI) and three irrigated areas meeting 50% (T50%), 100% (T100%) and 200% (T200%) of the crop's water need between each round of irrigation. T100% and T200% provided smaller areas and lengths of roots in the two deepest layers, as compared to AWI and T50%, which stimulated the development of deeper roots due to the water stress. TWI, T100% and T200% presented 80% of the roots up to a depth of 0.40m and T50% treatment presented 76.43% of roots total.

Deficit irrigation in a production setting: canopy temperature as an adjunct to ET estimates

Water available for agricultural use is declining worldwide as a result of both declining water resources and increasing application costs. Managing crop irrigation under conditions where the water need cannot be fully met represents the future of irrigation in many areas. On the southern high plains of Texas there is interest among producers to reduce the amount of water applied to cotton. In this study, a producer’s efforts to reduce water application to a cotton crop were assessed in terms of a comparison between evapotranspiration, rainfall, and irrigation that is widely used in the region. The producer was able to reduce water application to meet intended reductions relative to the evapotranspiration estimates but, depending on the method used for calculating the crop water need, he tended to over water the crop in two out of three intended deficit irrigation regimes. Analysis of continuously monitored canopy temperatures provided verification of over-irrigation. Continuously monitored canopy temperature is proposed as a useful adjunct to evapotranspiration approaches to deficit irrigation management.

Evaluation of irrigation management in a Canal Command area based on Agrometeorology and Remote Sensing

Efficacy of irrigation management of wheat and mustard crops grown in Western Yamuna Canal Command area was determined in the present study from agro-climatic data merged with Maximum Likelihood Classified (MXL) satellite image and from irrigation scheduling efficiencies obtained through FAO model CROPWAT. For computing irrigation scheduling efficiencies, amount of water supplied at different growth stages, soil water depletion and crop water need have been taken into account. Agro-meteorological data in combination with MXL classified crop map approximated the deficiency of applied irrigation amount compared to requirement. Irrigations at 35-80 Days After Sowing (DAS) for two times of applications, 30-60-90 DAS for three, 21-50-80-110 DAS in case of four and 20-45-70-90-120 DAS in case of five irrigations have yielded better scheduling efficiencies for wheat than other times of applications in all soil associations.