Advances in precision agriculture in south-eastern Australia. IV. Spatial variability in plant-available water capacity of soil and its relationship with yield in site-specific management zones

2009 ◽  
Vol 60 (9) ◽  
pp. 885 ◽  
Author(s):  
M. A. Rab ◽  
P. D. Fisher ◽  
R. D. Armstrong ◽  
M. Abuzar ◽  
N. J. Robinson ◽  
...  

Spatial variability in grain yield can arise from variation in many different soil and terrain properties. Identification of important sources of variation that bear significant relationship with grain yield can help achieve more effective site-specific management. This study had three aims: (i) a geostatistical description/modelling of the paddock-level spatial structure in variability of plant-available water capacity (PAWC) and related soil properties, (ii) to determine optimal number of management zones in the paddock, and (iii) to assess if the variability in PAWC and related soil properties is significantly associated with the variability in grain yield across the management zones. Particle size distribution, bulk density (BD), field capacity (FC), permanent wilting point (PWP), and soil water content (SWC) at sowing were measured at 4 soil depths (to 0.60 m) at 50 representative spatial sampling locations across a paddock near Birchip (Victoria). PAWC and plant-available water at sowing (PAWs) were derived from these data. Moderate to strong spatial dependence across the paddock was observed. The magnitude of the structural variation and of range varied widely across different soil properties and depths. The south-east edge and the central areas of the paddock had higher clay content, FC, PWP, PAWC, and lower PAWs. The paddock was divided into 6 potential management zones using combined header yield and normalised difference vegetation index (NDVI). The adequacy of zoning was evaluated using relative variability (RV) of header yield and soil properties. The mean RV for 3 zones differed little from that of 6 management zones for header yield and for each measured soil property, indicating division of the paddock into 3 zones to be adequate. The results from residual maximum likelihood (ReML) analysis showed that low yield zones had significantly higher clay content, FC, PWP, SWC, and PAWC and significantly lower PAWs than both medium and high yield zones. The mean FC, PWP, and PAWC in the low yield zones were, respectively, 25%, 26%, and 28% higher, and PAWs 36% lower than their corresponding values in the high yield zones. Linear regression analysis indicated that 59–96% of the observed variation in grain yield across management zones could be explained by variation in PWP. The practical implications of these results are discussed.

2009 ◽  
Vol 33 (6) ◽  
pp. 1547-1560 ◽  
Author(s):  
José Miguel Reichert ◽  
Jackson Adriano Albuquerque ◽  
Douglas Rodrigo Kaiser ◽  
Dalvan José Reinert ◽  
Felipe Lavarda Urach ◽  
...  

Dispersed information on water retention and availability in soils may be compiled in databases to generate pedotransfer functions. The objectives of this study were: to generate pedotransfer functions to estimate soil water retention based on easily measurable soil properties; to evaluate the efficiency of existing pedotransfer functions for different geographical regions for the estimation of water retention in soils of Rio Grande do Sul (RS); and to estimate plant-available water capacity based on soil particle-size distribution. Two databases were set up for soil properties, including water retention: one based on literature data (725 entries) and the other with soil data from an irrigation scheduling and management system (239 entries). From the literature database, pedotransfer functions were generated, nine pedofunctions available in the literature were evaluated and the plant-available water capacity was calculated. The coefficient of determination of some pedotransfer functions ranged from 0.56 to 0.66. Pedotransfer functions generated based on soils from other regions were not appropriate for estimating the water retention for RS soils. The plant-available water content varied with soil texture classes, from 0.089 kg kg-1 for the sand class to 0.191 kg kg-1 for the silty clay class. These variations were more related to sand and silt than to clay content. The soils with a greater silt/clay ratio, which were less weathered and with a greater quantity of smectite clay minerals, had high water retention and plant-available water capacity.


2002 ◽  
Vol 11 (4) ◽  
pp. 381-390
Author(s):  
A. TALKKARI ◽  
L. JAUHIAINEN ◽  
M. YLI-HALLA

In precision farming fields may be divided into management zones according to the spatial variation in soil properties. Clay content is an important soil characteristic, because it is associated with other soil properties that are important in management. Soil survey data from 150 sampling sites taken from an area of 218 ha were used to predict the spatial variation of clay percentage geostatistically in an agricultural soil in Jokioinen, Finland. The exponential and spherical models with a nugget component were fitted to the experimental variogram. This indicated that the medium-range pattern could be modelled, but the short-range variation could not, due to sparsity of sample points at short distances. The effect of sampling density on the kriging error was evaluated using the random simulation method. Kriging with a spherical model produced a map with smooth variation in clay percentage. The standard error of kriging estimates decreased only slightly when the density of samples was increased. The predictions were divided into three classes based on the clay percentage. Areas with clay content below 30%, between 30% and 60% and over 60% belong to non-clay, clay and heavy clay zones, respectively. With additional information from the soil samples on the contents of nutrients and organic matter these areas can serve as agricultural management zones.;


Rangifer ◽  
2004 ◽  
pp. 83-91 ◽  
Author(s):  
Christian Uhlig ◽  
Tore E. Sveistrup ◽  
Ivar Schjelderup

Numerous investigations have documented changes in vegetation due to reindeer grazing in Finnmark County, Northern Norway. However, rather few studies have focused on impacts of reindeer grazing on soil properties. The aim of this investigation was to identify possible changes in physical and chemical soil properties due to reindeer grazing. Furthermore, root distribution was detected. At four different locations on Finnmarksvidda three sample sites each were selected subjectively according to lichen and plant cover: A) ample, B) reduced, and C) poor lichen and plant cover. It was supposed that differences in lichen and plant cover were due to differences in reindeer grazing intensity. Results showed that the organic layer beneath ample lichen cover had an about 20% higher CEC and a 30—50% higher concentration of plant available Ca and Mg and total Mg compared to those beneath reduced ones. At sites with poor lichen and plant cover, an organic layer was mostly missing. The exposed mineral Eh-horizons at these sites had a significant (P<0.05) higher organic C content, higher CEC, concentrations of total P, Ca and K, and plant available K, when compared to E-horizons beneath better lichen covers. Rooting depth and amounts of plant available water in the rooting zone were lower at sites with reduced and poor lichen cover. A relation was found between soil organic C and CEC for all soil samples, indicating that soil organic matter is an essential key factor for soil fertility at the investigate sites on Finnmarksvidda. Assuming that differences in lichen and plant cover are related to differences in grazing intensity, results indicate that overgrazing by reindeers can cause a significant degradation of the organic layer, followed by significant losses of essential plant nutrients, a reduction in plant available water and consequently soil fertility.


2012 ◽  
Vol 58 (10) ◽  
pp. 1075-1090 ◽  
Author(s):  
Hou-Long Jiang ◽  
Guo-Shun Liu ◽  
Shu-Duan Liu ◽  
En-Hua Li ◽  
Rui Wang ◽  
...  

2019 ◽  
Vol 45 (1) ◽  
pp. 23-27
Author(s):  
Erlei Melo Reis ◽  
Mateus Zanatta ◽  
Carlos Alberto Forcelini

ABSTRACT Wheat leaf blights caused by Drechslera siccans, D. tritici-repentis, especially D. tritici-repentis, are difficult to be controlled by site-specific fungicide mixtures. Due to development of resistance, the use of double site-specific mixtures has shown control inferior to 50%. In an experiment conducted in the field with the wheat cultivar Jadeite 11, in 3 x 6 m plots and four replicates, the effect of a muli-site fungicide added to fungicide mixtures on the control of leaf blights was evaluated. The effect of the following mixtures was evaluated: picoxystrobin + cyproconazole, kresoxim-methyl + epoxiconazole, azoxystrobin + cyproconazole, pyraclostrobin + epoxiconazole, pyraclostrobin + fluxapyroxad, trifloxystrobin + prothioconazole and azoxystrobin + propiconazole, added of five mancozeb levels, 0; 1.5; 2.0; 2.5 and 3.0 kg/ha. The first application occurred after 30% leaf incidence, and the remaining two occurred at 15 and 18-day intervals. The fungicides were applied with a backpack sprayer pressurized by CO2, delivering 180 L/ha. Leaf blights severity was quantified, control was calculated, the percentage of chlorophyll in flag leaves was determined, and grain yield was assessed. The mean control of leaf blights by the mixtures without addition of the multi-site fungicide was 44%. The disease severity reduced as a function of the addition of mancozeb levels for all treatments. Control superior to 80% was obtained with the mixtures kresoxim methyl + epoxiconazole and pyraclostrobin + epoxiconazole, both added at least 2.0 kg/ha mancozeb. There was a positive reflex on the increase in wheat grain yield as a function of control, varying from 3005 kg/ha for the best treatment to 2026 kg/ha for control.


Agronomy ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 2005
Author(s):  
Jacek Długosz ◽  
Anna Piotrowska-Długosz ◽  
Karol Kotwica ◽  
Ewelina Przybyszewska

The application of various conditioners in agriculture is one of the management practices used to improve soil quality and plant growth and development. The aim of this study was to assess the effect of a multi-component conditioner on the selected soil properties and maize (Zea mays L.) growth and yield. The effect of a conditioner on a set of soil properties and maize growth and yield was studied in one-year experiments carried out at three study sites, which were under a conventional tillage system. All of the study sites were located on farms in three geographic mezoregions in the Kuyavian-Pomeranian Region (Midwestern Poland). The studied soils were Haplic Luvisol (Janocin and Kobylnica) and Albic Luvisols (Krukówko) that were composed of sandy loam. A one-way analysis of variance (ANOVA) was used to determine the effect of a conditioner Solactiv on the soil and plant properties. The conditioner significantly affected the soil enzyme activities such as dehydrogenase (DHA), fluorescein sodium salt hydrolysis level (FDAH) and carboxymethylcellulose cellulase (CMC—cellulase); wherein the last one increased by about 16–20%. The application of Solactiv also increased the available K content (about 11%) but not the content of the microbial biomass C and N. Total porosity (TP), which was significantly higher in the soil treated with conditioner than in the control soils, increased the available water capacity (AWC) (about 2.2%). The higher AWC in the treated soil indicated the greater contribution of the mesopores in the TP (about 4%). A significantly higher readily available water capacity (RAWC) and small pores available water capacity (SAWC) was determined in the treated soils compared to the controls. Of the plant properties, only plant height, fresh cob biomass (BBCH 87–89) and fresh plant biomass (BBCH 84–85) were significantly increased by the conditioner. The application of Solactiv is considered to be a promising approach for developing sustainable agriculture by improving the soil’s biological activity and water-related properties.


2007 ◽  
Vol 71 (6) ◽  
pp. 1902-1908 ◽  
Author(s):  
Pingping Jiang ◽  
Stephen H. Anderson ◽  
Newell R. Kitchen ◽  
Kenneth A. Sudduth ◽  
E. John Sadler

2009 ◽  
Vol 60 (9) ◽  
pp. 870 ◽  
Author(s):  
R. D. Armstrong ◽  
J. Fitzpatrick ◽  
M. A. Rab ◽  
M. Abuzar ◽  
P. D. Fisher ◽  
...  

A major barrier to the adoption of precision agriculture in dryland cropping systems is our current inability to reliably predict spatial patterns of grain yield for future crops for a specific paddock. An experiment was undertaken to develop a better understanding of how edaphic and climatic factors interact to influence the spatial variation in the growth, water use, and grain yield of different crops in a single paddock so as to improve predictions of the likely spatial pattern of grain yields in future crops. Changes in a range of crop and soil properties were monitored over 3 consecutive seasons (barley in 2005 and 2007 and lentils in 2006) in the southern section of a 167-ha paddock in the Mallee region of Victoria, which had been classified into 3 different yield (low, moderate, and high) and seasonal variability (stable and variable) zones using normalised difference vegetation index (NDVI) and historic yield maps. The different management zones reflected marked differences in a range of soil properties including both texture in the topsoil and potential chemical-physical constraints in the subsoil (SSCs) to root growth and water use. Dry matter production, grain yield, and quality differed significantly between the yield zones but the relative difference between zones was reduced when supplementary irrigation was applied to barley in 2005, suggesting that some other factor, e.g. nitrogen (N), may have become limiting in that year. There was a strong relationship between crop growth and the use of soil water and nitrate across the management zones, with most water use by the crop occurring in the pre-anthesis/flowering period, but the nature of this relationship appeared to vary with year and/or crop type. In 2006, lentil yield was strongly related to crop establishment, which varied with soil texture and differences in plant-available water. In 2007 the presence of soil water following a good break to the season permitted root growth into the subsoil where there was evidence that SSCs may have adversely affected crop growth. Because of potential residual effects of one crop on another, e.g. through differential N supply and use, we conclude that the utility of the NDVI methodology for developing zone management maps could be improved by using historical records and data for a range of crop types rather than pooling data from a range of seasons.


Sign in / Sign up

Export Citation Format

Share Document