scholarly journals Conservation and consumptive use of water with sugar cane under irrigation in the south coastal area of Puerto Rico

1969 ◽  
Vol 35 (1) ◽  
pp. 1-47
Author(s):  
D. K. Fuhriman ◽  
R. M. Smith
Keyword(s):  
Puerto Rico ◽  
Soil Moisture ◽  
Puerto Rican ◽  
Sugar Cane ◽  
High Efficiency ◽  
Root Zone ◽  
Field Scale ◽  
Consumptive Use ◽  
Irrigation Methods ◽  
Weather Factor

1. Prevailing methods of irrigation in Puerto Rico can be reasonably efficient in the use of water (about 50% retained) if the systems are carefully laid out and if the irrigators are well trained and conscientious. With the standard, short-run, big-furrow, McLane methods the greatest losses are caused by applying too much water in one irrigation and by applying water at times when the soil has very little available storage capacity. At its best, the short furrow (McLane) method has a high labor requirement and is therefore rather expensive. Properly designed sprinkler irrigation has shown a consistently high efficiency of about 75%. Major changes in irrigation methods, other than by sprinkling, would require alteration of field lay-outs, land preparation, cultural operations, and labor practices. Further study is needed to determine whether some such alterations might be feasible, and compatible with high cane yields. There are too many interdependent factors to permit much change in irrigation methods without upsetting other features of the system of cane culture as a whole. Details of irrigation methods (9) and of their efficiency (8) have already been reported elsewhere. 2. Regardless of the irrigation methods used, the periods of greatest opportunity for saving water with sugar cane are the first few and the last few months of the crop season. The greatest danger of damage to the crop because of lack of water normally comes during the season of peak growth which also corresponds with the highest average temperatures. Consumptive use of water at this time averages about 0.18 inch per day compared to 0.10 or 0.12 during the first and the last part of the season. 3. Soil moisture guides appear to offer the most promising present basis for determining when to irrigate. By depending upon soil moisture rather than upon arbitrary schedules or field men's judgment it appears to be possible to increase cane yields, save water, and save labor, all at the same time. These indications are being given extensive field scale tests by Luce and Co. at Aguirre. Both mercury type, tensiometers (constructed by the BPISAE shop at Beltsville) and Boyoucos type nylon resistance blocks are giving satisfactory results. The blocks are preferred because of simplicity of operations. Normal salt variations in soil have not affected block readings. Inherent block errors and block failures have been satisfactorily overcome by using 4 or more replicates at carefully selected stations representing a unit irrigation area. Any blocks which deviate seriously from the average are removed and replaced. The resistance or tension readings which serve as the basis for irrigation have been established by our tank and field studies and by laboratory soil moisture tension curves. For soil like the Santa Isabel clay in the area from Juana Díaz to Aguirre it is not safe to let the soil moisture tension in the main root zone of cane go much beyond one atmosphere. With any Puerto Rican soil a safe tension for irrigation should probably correspond with a point which is at least 5% above the wilting point on a laboratory pF (moisture retention) curve. 4. Present field results indicate that high sugar cane yields per acre probably mean less water use per unit of crop produced. This is the basis for a field scale experiment by Luce and Co. comparing two, block-controlled soil moisture levels, each with two levels of fertilization. 5. Under Puerto Rican conditions, crop characteristics and soil moisture levels probably overshadow the influence of variations in the weather factor on evapotranspiration much more often than under climates of the temperate zone where the weather factor is highly variable. In any detailed considerations of climatic influences, the weather records from Aguirre, San Juan, and Mayagüez, indicate that differences in wind movement should be given major consideration along with hours of sunshine and seasonal temperatures.

ВОДНЫЙ РЕЖИМ ОРОШАЕМЫХ СОЛОНЦОВЫХ КОМПЛЕКСНЫХ ПОЧВ И ОСОБЕННОСТИ ЕГО РЕГУЛИРОВАНИЯ

2020 ◽  
Author(s):  
Valery Yashin
Keyword(s):  
Soil Moisture ◽  
Ground Water ◽  
Irrigation Water ◽  
Surface Runoff ◽  
Root Zone ◽  
Irrigation Methods ◽  
Salt Flats

Представлены материалы исследований формирования режима влажности и динамики грунтовых вод орошаемых солонцовых комплексных почв при различных способах полива, проведенные в Волгоградском Заволжье. Установлена значительная неравномерность распределения влажности почвы при поливах дождеванием. Отмечается поверхностный сток по микрорельефу до 30% от поливной нормы, что приводит к недостаточности увлажнения корневой зоны на солонцах и переувлажнению почв в понижениях микрорельефа и потере оросительной воды на инфильтрационное питание грунтовых вод.The article presents the materials of research on the formation of the humidity regime and dynamics of ground water of irrigated saline complex soils under various irrigation methods, conducted in the Volgograd Zavolzhye. A significant unevenness in the distribution of soil moisture during irrigation with sprinkling has been established. There is a surface runoff on the microrelief of up to 30% of the irrigation norm, which leads to insufficient moisture of the root zone on the salt flats and waterlogging of the soil in the microrelief depressions and loss of irrigation water for infiltration feed of ground water.

scholarly journals Field-scale soil moisture bridges the spatial-scale gap between drought monitoring and agricultural yields

2020 ◽  
Author(s):  
Noemi Vergopolan ◽  
Sitian Xiong ◽  
Lyndon Estes ◽  
Niko Wanders ◽  
Nathaniel W. Chaney ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Spatial Scale ◽  
Root Zone ◽  
Maize Yield ◽  
Remotely Sensed ◽  
Drought Monitoring ◽  
Surface Model ◽  
Field Scale ◽  
Yield Data ◽  
Scale Modeling

Abstract. Soil moisture is highly variable in space, and its deficits (i.e. droughts) plays an important role in modulating crop yields and its variability across landscapes. Limited hydroclimate and yield data, however, hampers drought impact monitoring and assessment at the farmer field-scale. This study demonstrates the potential of field-scale soil moisture simulations to advance high-resolution agricultural yield prediction and drought monitoring at the smallholder farm field-scale. We present a multi-scale modeling approach that combines HydroBlocks, a physically-based hyper-resolution Land Surface Model (LSM), and machine learning. We applied HydroBlocks to simulate root zone soil moisture and soil temperature in Zambia at 3-hourly 30-m resolution. These simulations along with remotely sensed vegetation indices, meteorological conditions, and data describing the physical properties of the landscape (topography, land cover, soil properties) were combined with district-level maize data to train a random forest model (RF) to predict maize yields at the district- and field-scale (250-m) levels. Our model predicted yields with a coefficient of variation (R2) of 0.61, Mean Absolute Error (MAE) of 349 kg ha−1, and mean normalized error of 22 %. We captured maize losses due to the 2015/2016 El Niño drought at similar levels to losses reported by the Food and Agriculture Organization (FAO). Our results revealed that soil moisture is the strongest and most reliable predictor of maize yield, driving its spatial and temporal variability. Consequently, soil moisture was also the most effective indicator of drought impacts in crops when compared with precipitation, soil and air temperatures, and remotely-sensed NDVI-based drought indices. By combining field-scale root zone soil moisture estimates with observed maize yield data, this research demonstrates how field-scale modeling can help bridge the spatial scale discontinuity gap between drought monitoring and agricultural impacts.

scholarly journals Response of Native White Sorghum to Irrigation under Different Nitrogen-Fertility Levels and Seeding Rates in Lajas Valley, Puerto Rico

1969 ◽  
Vol 50 (2) ◽  
pp. 92-112
Author(s):  
R. Vázquez ◽  
A. Eschenwald-Hess ◽  
M. J. Martínez-Luciano
Keyword(s):  
Puerto Rico ◽  
Soil Moisture ◽  
Field Experiment ◽  
Dry Matter ◽  
Root Zone ◽  
High Moisture ◽  
Nitrogen Levels ◽  
Nitrogen Fertility ◽  
Native White ◽  
Active Root

A field experiment was conducted at Lajas Substation in order to study the effects of four irrigation and three nitrogen levels under three different seeding rates on dry-matter yields of White Native sorghum. The following irrigation treatments were tried: High moisture, plots irrigated when the average soil-moisture suction in the active root-zone reached 0.7 atm.; medium moisture, irrigated when the average soil-moisture suction reached 2.0 atm.; low moisture, irrigated when the average soil-moisture suction reached 5.0 atm., and nonirrigated plots were used as check. The nitrogen levels tested were 40, 80, and 120 pounds per acre per harvest. The seeding rates used were 10, 20, and 30 pounds per acre.

Cosmic Ray Neutron Sensing: Integration with land surface modelling using data assimilation for improved field-scale soil moisture estimates

2020 ◽  
Author(s):  
Amol Patil ◽  
Benjamin Fersch ◽  
Harrie-Jan Hendricks-Franssen ◽  
Harald Kunstmann
Keyword(s):  
Soil Moisture ◽  
Data Assimilation ◽  
Spatial Resolution ◽  
Land Surface ◽  
Root Zone ◽  
Cosmic Ray ◽  
Soil Parameters ◽  
Surface Model ◽  
Field Scale ◽  
Spatio Temporal

<p>Soil moisture is a key variable in atmospheric modelling to resolve the partitioning of net radiation into sensible and latent heat fluxes. Therefore, high resolution spatio-temporal soil moisture estimation is getting growing attention in this decade. The recent developments to observe soil moisture at field scale (170 to 250 m spatial resolution) using Cosmic Ray Neutron Sensing (CRNS) technique has created new opportunities to better resolve land surface atmospheric interactions; however, many challenges remain such as spatial resolution mismatch and estimation uncertainties. Our study couples the Noah-MP land surface model to the Data Assimilation Research Testbed (DART) for assimilating CRN intensities to update model soil moisture. For evaluation, the spatially distributed Noah-MP was set up to simulate the land surface variables at 1 km horizontal resolution for the Rott and Ammer catchments in southern Germany. The study site comprises the TERENO-preAlpine observatory with five CRNS stations and additional CRNS measurements for summer 2019 operated by our Cosmic Sense research group. We adjusted the soil parametrization in Noah-MP to allow the usage of EU soil data along with Mualem-van Genuchten soil hydraulic parameters. We use independent observations from extensive soil moisture sensor network (SoilNet) within the vicinity of CRNS sensors for validation. Our detailed synthetic and real data experiments are evaluated for the analysis of the spatio-temporal changes in updated root zone soil moisture and for implications on the energy balance component of Noah-MP. Furthermore, we present possibilities to estimate root zone soil parameters within the data assimilation framework to enhance standalone model performance.</p>

Field scale root zone soil moisture estimation by coupling cosmic-ray neutron sensor with soil moisture sensors

2020 ◽  
Author(s):  
Hami Said ◽  
Georg Weltin ◽  
Lee Kheng Heng ◽  
Trenton Franz ◽  
Emil Fulajtar ◽  
...  
Keyword(s):  
Water Management ◽  
Soil Moisture ◽  
Root Zone ◽  
Cosmic Ray ◽  
Agricultural Water ◽  
Field Scale ◽  
Agricultural Water Management ◽  
Soil Moisture Sensors ◽  
Major Disadvantage ◽  
Filter Approach

<p>Since it has become clear that climate change is having a major impact on water availability for agriculture and crop productivity, an accurate estimation of field-scale root-zone soil moisture (RZSM) is essential for improved agricultural water management. The Cosmic Ray Neutron Sensor (CRNS) has recently been used for field-scale soil moisture (SM) monitoring in large areas and is a credible and robust technique. Like other remote or proximal sensing techniques, the CRNS provides only SM data in the near surface. One of the challenges and needs is to extend the vertical footprint of the CRNS to the root zone of major crops. This can be achieved by coupling the CRNS measurements with conventional methods for soil moisture measurements, which provide information on soil moisture for whole rooting depth.</p><p>The objective of this poster presentation is to estimate field-scale RZSM by correlating the CRNS information with that from soil moisture sensors that provide soil moisture data for the whole root depth. In this study, the Drill and Drop probes which provide continuous profile soil moisture were selected. The RZSM estimate was calculated using an exponential filter approach.</p><p>Winter Wheat cropped fields in Rutzendorf, Marchfeld region (Austria) were instrumented with a CRNS and Drill & Drop probes. An exponential filter approach was applied on the CRNS and Drill and drop sensor data to characterize the RZSM. The preliminary results indicate the ability of the merging framework procedure to improve field-scale RZSM in real-time. This study demonstrated how to combine the advantages of CRNS nuclear technique (especially the large footprint and good representativeness of obtained data) with the advantages of conventional methods (providing data for whole soil profile) and overcome the shortcoming of both methods (the lack of information in the deeper part of soil profile being the major disadvantage of CRNS and the spatial limitation and low representativeness of point data being the major disadvantage of conventional capacitance sensors). This approach can be very helpful for improving agricultural water management.</p>

scholarly journals Fuzzy and process modelling of contour ridge water dynamics

2018 ◽  
Vol 378 ◽  
pp. 3-10
Author(s):  
Alexander Mhizha ◽  
John Ndiritu
Keyword(s):  
Fuzzy Logic ◽  
Soil Moisture ◽  
Rainwater Harvesting ◽  
Root Zone ◽  
Process Modelling ◽  
Water Dynamics ◽  
Field Scale ◽  
Model Soil ◽  
Distributed Process ◽  
Using Data

Abstract. Contour ridges are an in-situ rainwater harvesting technology developed initially for soil erosion control but are currently also widely promoted for rainwater harvesting. The effectiveness of contour ridges depends on geophysical, hydro-climatic and socio economic factors that are highly varied in time and space. Furthermore, field-scale data on these factors are often unavailable. This together with the complexity of hydrological processes at field scale limits the application of classical distributed process modelling to highly-instrumented experimental fields. This paper presents a framework that combines fuzzy logic and process-based approach for modelling contour ridges for rainwater harvesting where detailed field data are not available. Water balance for a representative contour-ridged field incorporating the water flow processes across the boundaries is integrated with fuzzy logic to incorporate the uncertainties in estimating runoff. The model is tested using data collected during the 2009/2010 and 2010/2011 rainfall seasons from two contour-ridged fields in Zhulube located in the semi-arid parts of Zimbabwe. The model is found to replicate soil moisture in the root zone reasonably well (NSE = 0.55 to 0.66 and PBIAS = −1.3 to 6.1 %). The results show that combining fuzzy logic and process based approaches can adequately model soil moisture in a contour ridged-field and could help to assess the water dynamics in contour ridged fields.

scholarly journals Modelling field scale water partitioning using on-site observations in sub-Saharan rainfed agriculture

2009 ◽  
Vol 6 (4) ◽  
pp. 5537-5563 ◽  
Author(s):  
H. Makurira ◽  
H. H. G. Savenije ◽  
S. Uhlenbrook
Keyword(s):  
Soil Moisture ◽  
Water Balance ◽  
Root Zone ◽  
Crop Growth ◽  
Deep Percolation ◽  
Field Scale ◽  
Dry Spell ◽  
Water Partitioning ◽  
Cultivation Techniques ◽  
Storage Structures

Abstract. Smallholder rainfed farming systems generally realise sub-optimal crop yields which are largely attributed to dry spell occurrences during crop growth stages. However, with improved farming practices, it seems possible to significantly increase yield levels even with little and highly variable rainfall. The presented results follow research conducted in the Makanya catchment in northern Tanzania where gross rainfall amounts to less than 400 mm/season which is insufficient to support staple food crops (e.g. maize). Alternative cultivation techniques such as runoff harvesting and in-field micro-storage structures are compared. These techniques aim to reduce soil and nutrient loss from the field but, more importantly, promote in-field infiltration and water retention. Water balance components have been observed in order to study water partitioning processes under different cultivation techniques. Based on rainfall, soil evaporation, transpiration, runoff and soil moisture measurements, a water balance model has been developed to simulate soil moisture variations over the growing season. It appears that about 50% of the diverted water leaves the root zone through deep percolation. Modelling shows that during the field trials the average productive transpiration flow ranged between 1.1–1.4 mm d−1 in the trial plots compared to 0.7–1.0 mm d−1 under traditional tillage practice. Productive transpiration processes accounted for 23–29% while losses to deep percolation accounted for 33–48% of the available water. Conclusions from the research are that the innovations tested are effective in enhancing soil moisture retention at field scale and that diversions allow crop growth moisture conditions to be attained with early rains. It is also concluded that there is more scope for efficient utilisation of the diverted runoff water if storage structures could be installed to regulate water flow to the root zone when required.

scholarly journals Estimating field scale root zone soil moisture using the cosmic-ray neutron probe

2015 ◽  
Vol 12 (12) ◽  
pp. 12789-12826 ◽  
Author(s):  
A. M. Peterson ◽  
W. D. Helgason ◽  
A. M. Ireson
Keyword(s):  
Soil Moisture ◽  
Root Zone ◽  
Cosmic Ray ◽  
Estimation Methods ◽  
Filter Method ◽  
Field Scale ◽  
Landscape Unit ◽  
Neutron Probe ◽  
Cumulative Change ◽  
Stability Method

Abstract. Many practical hydrological, meteorological and agricultural management problems require estimates of soil moisture with an areal footprint equivalent to "field scale", integrated over the entire root zone. The cosmic-ray neutron probe is a promising instrument to provide field scale areal coverage, but these observations are shallow and require depth scaling in order to be considered representative of the entire root zone. A study to identify appropriate depth-scaling techniques was conducted at a grazing pasture site in central Saskatchewan, Canada over a two year period. Area-averaged soil moisture was assessed using a cosmic-ray neutron probe. Root zone soil moisture was measured at 21 locations within the 5002 m2 area, using a down-hole neutron probe. The cosmic-ray neutron probe was found to provide accurate estimates of field scale surface soil moisture, but accounted for less than 40 % of the seasonal change in root zone storage due to its shallow measurement depth. The root zone estimation methods evaluated were: (1) the coupling of the cosmic-ray neutron probe with a time stable neutron probe monitoring location, (2) coupling the cosmic-ray neutron probe with a representative landscape unit monitoring approach, and (3) convolution of the cosmic-ray neutron probe measurements with the exponential filter. The time stability method provided the best estimate of root zone soil moisture (RMSE = 0.004 cm3 cm−3), followed by the exponential filter (RMSE = 0.012 cm3 cm−3). The landscape unit approach, which required no calibration, had a negative bias but estimated the cumulative change in storage reasonably. The feasibility of applying these methods to field sites without existing instrumentation is discussed. It is concluded that the exponential filter method has the most potential for estimating root zone soil moisture from cosmic-ray neutron probe data.

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