Irrigated Grain Research Articles

Distribution and redistribution of mineral nutrients and dry matter in grain sorghum as affected by soil salinity

Abstract A study was made of the effects of soil salinity on dry matter production, grain yield, and the uptake, distribution and redistribution of mineral nutrients in irrigated grain sorghum. Soil salinity (EC, 3.6 mS/cm) reduced seedling establishment by 77%, and dry matter and grain yields per plant by 32%; grain yield/ha was reduced by 84%. Salinity reduced grain number per head, but not individual grain size. The accumulation of dry matter and most nutrients was reduced by salinity, but the distribution and redistribution of nutrients within the plant were largely unaffected. Redistributed dry matter provided 52 and 31% of the grain dry matter for control and salt‐affected plants, respectively. Salt‐affected plants had a greater proportion of their sulfur (S), magnesium (Mg), sodium (Na), and chloride (Cl) in stems and leaves than control plants at maturity. Grain had 50–90% of the nitrogen <N), phosphorus (P), S, and Mg, 20–50% of the potassium (K), manganese (Mn), zinc (Zn), and copper (Cu), but <...

THE FARM LEVEL EFFECTIVENESS OF SELECTED IRRIGATION POLICY MEASURES1

ABSTRACT: The on‐farm economic effectiveness of government capital grants, subsidized interest rates, and the Canadian Wheat Board (CWB) delivery quota levels in terms of adoption and/or expansion of irrigation in Saskatchewan is tested. The annualized net income at 5 and 20 years of three representative farm types ‐ a dryland grain farm, an irrigated grain farm, and an irrigated mixed farm ‐ are used in the analysis. Tradeoffs between income levels and the risks associated with adoption/expansion of irrigation are evaluated using mean‐standard deviation tradeoff and stochastic dominance. Risk differences arise due to reduced business risk through higher yields and increased financial risk through higher borrowing when adopting or expanding irrigation. Capital grants and subsidized interest rates are effective policy measures for dryland grain farms adopting irrigation because the farms are left in a similar risk position. However, these grants and interest rates are not effective policy measures in the medium run (5 years) for irrigated grain farms expanding irrigation because they lower the farm's risk efficiency. In the long run (20 years), the capital grants and subsidized interest rates need to be combined with open CWB delivery quotas before the risk position can be improved for irrigated grain farms expanding irrigation. Finally, the grants and interest rates need to be combined with increased irrigated hay production for risk efficiency to increase in both the medium and long run (5 and 20 years, respectively) on irrigated mixed farms expanding irrigation.

Effects of application of water and nitrogen on nutrient use from corn and sorghums by pigs (1993)

An experiment was conducted to determine the effects of growing conditions on nutrient yield and quality of corn and sorghum. Main effect treatments were: corn (C), bronze pericarp heterozygous-yellow endosperm sorghum (BS), and yellow pericarp homozygous-yellow endosperm sorghum (YS); optimal irrigation (I) and minimal irrigation (MI); 100 lb/acre of N fertilization (F) and no N fertilization (NF), in a 3 × 2 × 2 factorial arrangement. Grains were grown in 1988 (Year 1, with little rainfall) and 1989 (Year 2, with above average rainfall) in the semi-arid environment at Garden City, KS. In Year 1, sorghums yielded 15% more grain than C, and YS yielded 1.2% more grain than BS. Irrigation increased yield by 90%, and N application increased yield by 7%. In year 2, C yielded 11% more grain than the sorghums. In the pig metabolism study, C had greater nitrogen digestibility (ND) than sorghums in both years, greater biological value (BV) and nitrogen retention in Year 2, but lower BV in Year 1. Yellow sorghum had greater ND than BS in Year 1. Corn had increased cost per unit of utilizable nitrogen (CUN) and utilizable energy (CUE) and reduced utilizable nitrogen per inch of available water (UNW) and utilizable energy per inch of available water (UEW) for both years compared to BS and YS. In conclusion, optimally irrigated grains had higher nutritional value than minimally irrigated grains, and growing the grains under varying agronomic conditions did affect their nutritional quality.; Swine Day, Manhattan, KS, November 18,1993

Bonanza Club: 35 Years of Maximum Crop Production and Extension Education in Southwestern Kansas

The Bonanza Club was created by Grant County, Kansas, agricultural leaders in 1955, when rapid regional change was occurring. The Bonanza Club is one component of a county extension crops program. Its goal is to provide timely and useful information regarding new and successful agronomic practices applied by producers and to encourage the use of those that prove beneficial. Each year selected fields are enrolled by producers and cropping practices are documented. During a fall tour of enrolled fields, producers describe their production practices and local seed dealers, extension agents, and specialists discuss cultivars and practices. After fall harvest, worksheets are compiled into a report booklet, and an awards banquet is held to recognize participants and achievements. The report booklet is distributed at the awards banquet and to other interested extension and agribusiness personnel. As of 1989, 117 participants with 1200 crop entries representing 34 425 ha have been enrolled. The annual budget, $2200, is provided by local businesses. The fall crop tour and awards banquet have been well-attended. Bonanza Club grain yields of irrigated grain sorghum [Sorghum bicolor (L.) Moench.], corn (Zea mays L.), and wheat (Triticum aestivum L.) have averaged above county averages by 30, 12, and 41%, respectively. The Bonanza Club has been an excellent source of information for local producers and changing cropping practices have been documented in southwestern Kansas.

Effect of Composted Manure on Soil Chemical Properties and Nitrogen Use by Grain Sorghum

Compared to fresh manure, composting reduces material quantity, hauling and spreading costs, odor, and weed seed viability, while improving physical properties. The availability of nutrients for plant growth, however, may be less from manure compost. Objectives of this field study were to evaluate beef cattle manure compost as a nutrient source for irrigated grain sorghum [Sorghum bicolor (L.) Moench] and to determine the effects of annual compost and N fertilizer applications on soil chemical properties. Five rates of manure compost (0, 0.9, 1.8, 3.6, and 7.2 ton dry matter/acre) and four rates of N fertilizer (0, 55, 110, and 165 lb/acre) in a factorial arrangement were applied annually from 1987 to 1990 on a Ulysses silt loam (fine silty, mixed, mesic, Aridic Haplustoll) at Tribune, KS. Grain yields were greater from combinations of compost and N fertilizer than from either applied alone. The apparent fertilizer efficiency was 13% for compost compared with 36% for N fertilizer. Soil P, K, and organic matter increased linearly with increased rates of compost. Conversely, increased rates of N fertilizer decreased soil P and K, while having no effect on organic matter. Soil Na levels were increased by compost additions but not to excessive levels. Soil NO3−-N levels were not affected by compost applications but were increased by N fertilizer. Manure compost is effective for maintaining or increasing soil chemical levels, especially P, without excessive accumulation of NO3−; but should be applied with N fertilizer for optimum grain production.

Grazing Winter Wheat: II. Height Effects on Response to Production System

AbstractCurrent wheat (Triticum aestivum L.) cultivars are shorter and have more lodging resistance than previous cultivars. Thus, the reduction in height and lodging caused by grazing may be less desirable now than previously. The objective of this research was to compare the growth and yield response to grazing of hard red winter wheat cultivars that vary in height and other traits. Siouxland, a tall cultivar, Vona, a semidwarf, and Q588, a short hybrid, were grown 2 yr in irrigated grain and grazed production systems. In 1986, Siouxland yielded the same in grain and grazed systems and was insensitive to grazing termination date except that severe grazing after 15 March reduced yield 20%. In contrast, Vona and Q588 yielded less in all grazed systems than in the grain system and were more sensitive to grazing termination date than Siouxland because they had lower leaf area and headed earlier. Grazing until 29 March reduced yield of Vona and Q588 two to five times more than Siouxland. In 1987, grazing increased yield of Siouxland and Vona by 41 and 23%, respectively, while reducing yield of Q588 by 8% in a lodging‐prone environment (330 mm spring irrigation) because Siouxland and Vona lodged without grazing and Q588 did not. With 130 mm spring irrigation, lodging was less and all cultivars responded similiarly to grazing. In conclusion, grazing is more likely to reduce the yield of a lodging‐resistant short cultivar with high yield potential than a tall cultivar that is susceptible to lodging.

Grazing Winter Wheat: I. Response of Semidwarf Cultivars to Grain and Grazed Production Systems

AbstractMost wheat (Triticum aestivum L.) research in west Texas is conducted in ungrazed wheat that is managed solely for grain production (grain system). In contrast, most commercial wheat is planted early and grazed by cattle (Bos spp.) prior to management for grain production (grazed system). The objective of this research was to understand cultivar × production system interactions. Four semidwarf cultivars, TAM 105, Newton, Vona, and TAM 108, were grown in irrigated grain and grazed production systems for 3 yr. Grazed wheat headed 2.3 d later, had 57 and 62% as much above‐ground biomass and leaf area at heading, was 80% as tall, and yielded 80% as much as wheat grown in the grain system. There was a significant cultivar × system interaction for grain yield 2 yr (P = 0.088 in 1982, P = 0.001 in 1984) caused by differential cultivar response to yield constraints such as lodging, winterkilling, and shattering. In the 3‐yr combined analysis there was no cultivar × system interaction; however, the cultivar × system × year interaction for grain yield was significant (P = 0.003) because yield constraints within systems were not consistent across years. In 1984, extra fertilizer and insecticide reduced grain yield of TAM 108 by 18% (P = 0.001) in the grain system due to increased lodging while having no measurable effect on grain yield in the grazed system. If production systems frequently differ in type or degree of yield constraints, then breeders and agronomist must be concerned with cultivar × system interactions.

Assessment of dose to man from releases of 99Tc in fresh water systems.

The objective of this paper is to evaluate the dose to man from releases of 99Tc in a fresh water system and to identify the biospheric transfer parameters to which the total dose is the most sensitive. Only internal exposure is taken into account, as the external irradiation leads to a negligible dose contribution. Two release modes were considered: continuous (routine) releases and accidental releases. The concentrations in the biospheric compartments subsequent to routine releases were calculated according to International Atomic Energy Agency procedures. For the accidental releases, a more dynamic approach was adopted, especially for the milk and meat compartments. A routine-release scenario typical for the Mol site has been applied, and the biospheric compartment leading to the highest dose contribution was shown to be the irrigated grain. The biospheric transfer parameters to which the first-year doses were the most sensitive consisted mainly of the mass interception factor for grain and the milk transfer factor. The doses in following years were very dependent on the value of the root zone removal rate. The accidental-release scenario resulted in committed dose equivalent that are strongly influenced by the time of year at which the release occurs.

An analysis of the environmental limitation to yield of irrigated grain sorghum during the dry season in tropical Australia using a radiation, interception model

Variation in yield of irrigated grain sorghum (Sorghum bicolor L. Moench) grown during the dry season in tropical Australia was analysed in terms of the amount of photosynthetically active radiation (PAR) intercepted, its efficiency of use in dry matter production and the proportion of dry matter partitioned to grain. Three commercial hybrids (Texas 610SR, Dekalb DK55, Pacific Monsoon) grown under favourable conditions on two soil types (Cununurra Clay and Ord Sandy Loam) yielded similarly, but there was a significant effect of sowing date. Grain yield was highest (9.5 t ha-1 at 14% moisture) in the May sowing, with the lowest yield (7.4 t ha-1) being obtained in the April sowing. Yield was intermediate from a July sowing. Differences in grain yield across the dry season were not related to the amount of PAR intercepted, nor to the efficiency of conversion of intercepted PAR into net aboveground dry matter, but rather to differences in dry matter partitioning. A stable efficiency of conversion of 2.4 g MJ-1 of intercepted PAR was recorded for the entire crop cycle for sorghum crops growing under favourable growing conditions in this environment. This conversion efficiency for a tropical C4 cereal is similar to maximum values, but higher than average conversion efficiencies over the entire crop cycle obtained for temperate C3 cereals growing in temperate regions. Temperature did not affect this conversion efficiency, but had a pronounced effect on the duration of crop development.

Interfacing simulation models for predicting profitability of irrigated gain sorghum

A network-discrete event simulation model written in SLAM II is interfaced with a plant growth model to examine the impact that irrigation equipment failures have on crop production and profitability under irrigation scheduling of grain sorghum. The SLAM II simulation language provides a means of combining discrete and/or continuous simulation models with “real world” network interaction of the models. Results indicate that the timing and duration of the breakdown of irrigation equipment can have a significant impact on the profitability of irrigated grain sorghum.

Self-Regenerating Annual Forage Legumes for Double Cropping with Irrigated Wheat or Sorghum

SUMMARYTwo relay intercropping systems were investigated on an irrigated clay soil: first, wheat with a self-regenerating summer legume and, secondly, grain sorghum with a winter growing legume. A range of summer and winter legumes were evaluated. Phasey bean (Macroptilium lathyroides), a free seeding annual, regenerated vigorously as the wheat matured in early summer; cut twice after the wheat harvest it yielded (including the wheat stubble) 7.5 t ha−1 dry matter. Low seed production jeopardized the regeneration of other summer legumes. Subterranean clover (Trifolium subterraneum) regenerated under the maturing grain sorghum crop as did snail medic (Medicago scutellata) and woolly, pod vetch (Vicia dasycarpa). Together with the sorghum stubble they yielded 5–6 t ha−1 between sorghum crops. The benefits of including self-regenerating forage legumes in irrigated grain cropping systems is discussed.

Economic considerations of mouse-plague control in irrigated sunflower crops

During a localized plague of the house mouse ( Mus musculus) the population within an irrigated sunflower crop was estimated to be 2716 mice/ha 7 weeks before harvest. These mice were estimated to have caused a reduction of 12·4% of the expected yield up to that time. The crop was then subjected to a variety of control techniques, the most successful of which resulted in a reduction of 90% in the mouse population. Using 3·4 g/day as the amount of sunflower seed each mouse would consume or damage it was estimated that a 90% effective control programme would result in an increase of 20·4% in the harvested yield. Similar estimates for other irrigated grain crops indicate that mouse-plague control is an economically sound proposition.

Modelling seasonal grain sorghum yields in subtropical Australia

The seasonal variability of irrigated grain sorghum yields has been examined in terms of the quantitative effects of environmental variables on the yield components of the average genotype using stepwise regression techniques. Flow models have been formulated of yield development indicating the likely pattern of interaction between plant and environmental factors. Growth before anthesis affected both leaf area development (amount and display) and the number of sites (flowers) where grain could be produced. The most important yield component was grain number per unit ground area and this, more than grain size, affected the amount of photosynthate which could be stored. An equation was developed in which the assimilate produced before anthesis could be partitioned between vegetative dry matter production and number of flowers, according to accumulated temperature and radiation. Anthesis assimilate supply played a rôle in determining actual grain number set and influenced initial grain growth rates—and hence potential grain size. Post-anthesis assimilate surplus determined actual grain development and was related to temperature and radiation terms. It has been postulated that the balance between assimilate supply and respiratory loads during grainfilling dictates not only the magnitude of the optimum temperature response surface but also the tuning of the optimal temperature. Under reduced assimilate surplus, grain sorghum showed temperate, rather than tropical, growth behaviour, posing potential limits for tropical production zones.

SORGHUM AND BARLEY IN SOUTHERN ALBERTA: GRAIN YIELD RESPONSE TO IRRIGATION AND FERTILIZER

The seasonal water requirements of irrigated grain sorghum, the interaction between water use and applied N fertilizer, and the comparative water use efficiences of sorghum and barley were determined in southern Alberta over a 3-yr period. Peak daily water use of 6 mm for sorghum was 1 mm lower than that determined previously for barley. Seasonal water use (500 mm) was 20% greater than for barley because of sorghum’s longer growing season. Under adequate irrigation, both sorghum and barley responded linearly to applied N up to 80 kg/ha, but when water was restricted, sorghum showed less response than barley. Water-use efficiency (kg of grain/m3 of water used) decreased for both crops with increasing water availability but maximum yields were achieved under irrigation. When sorghum was favored with a long, warm growing season, it produced as much grain (6900 kg/ha) and used water as efficiently (1.25 kg/m3) as did barley.

Atrazine dissipation in irrigated sorghum cropping in southern New South Wales

Summary:Dissipation of atrazine after pre‐emergence application to irrigated grain sorghum was investigated in an experiment on a Birganbigil clay loam at Yanco Agricultural Research Centre in the Murrumbidgee Irrigation Areas of New South Wales. Dissipation followed first‐order kinetics with a half‐life of 70 days. This rate of disappearance did not differ significantly between application rates of 2.5 and 10 kg/ha. Removal of volunteer plant growth with non‐residual chemicals or by cultivation during the winter fallow periods had no significant effect on the levels of atrazine residues in the soil and dissipation rate did not differ significantly between the 2 years of the experiment. A laboratory incubation experiment demonstrated that dissipation of atrazine in Birganbigil soil was more rapid than in three other soils from the Murrumbidgee and Murray Valleys. Dissipation rate and atrazine adsorption were both correlated with the organic carbon content of the soils, which ranged from 1.43% to 0.72%. There was no correlation between either dissipation rate or adsorption and clay content, even though clay contents ranged from 37 to 78%.

Single vs. double cropping under two levels of fertilization with and without irrigation

Abstract A corn‐small grain cropping sequence resulted in a greater total grain yield than corn or small grain alone or grain sorghum double cropped with small grain. Drought restricted yield responses to N, P and K in non‐irrigated plots but under irrigation grain yield for each cropping sequence was directly related to fertilizer applied. All fertilizer treatments increased soil acidity. Phosphorus and K applied at 26 and 50 kg/ha, respectively for each crop in the sequence maintained P and K levels in the soil. After three years, the high rate of fertilizer (87 and 166 kg/ha of P and K, respectively) resulted in greater soil P and K values than the low rate of fertilizer.

Studies on the productivity of grain sorghum. II. Effects of wilting treatments at different stages of growth on the development, nitrogen uptake and yield of irrigated grain sorghum.

In pot trials sorghum cv. H-726 was irrigated when soil pF reached 1.5, 2.0, 2.5 or 2.8 beginning at the 4-leaf stage, or was subjected to drought periods of 4-36 days or to wilting, successive wilting when no recovery occurred at night, or further periods of 3 or 6 days without water. Successive wilting or severe moisture stress decreased growth, grain yield, fodder yield and grain protein content but not grain starch content. Water stress at heading retarded peduncle elongation while stress at early grain filling decreased panicle wt., grain number and dry wt./panicle and 1000-grain wt. Moderate water deficit tended to produce more elongated roots. Drought for 10 days at the vegetative stage increased growth and yield if wilting did not take place

Soil Water Depletion—Yield Relationships of Irrigated Sorghum, Wheat, and Soybeans

ABSTRACT A PPROXIMATELY 4 billion m3 A of groundwater is pumped annually to irrigate sorghum, wheat and soybeans grown in the fine-textured soils of the Southern High Plains. Declining groundwater storage and the high costs of pump-ing necessitate that water be applied only when it is needed to prevent appreciable yield reductions. Rela-tionships between soil water deple-tion and grain yields provide a rational basis for scheduling irrigations based on soil water in J:he major root zone. Relationships between soil water depletion on Pullman clay loam and yields of grain sorghum, winter wheat and soybeans were derived from 12-crop years of irrigation water manage-ment research conducted at the USDA Southwestern Great Plains Research Center, Bushland, Texas. Significant curvilinear relationships, which were fit by the general quad-ratic equation, were obtained in all years. Measured soil water deple-tion in the 0- to 120-cm depth accounted for 57 to 99 percent of the treatment yield variability within years. Depletion of soil water in the 0-to 120-cm depth to -15 bars potential resulted in best estimate relative yields of 73 percent for adequately irri-gated grain sorghum, 80 percent for winter wheat, and 47 percent for soybeans. The shape of the depletion-relative yield curves in the drierthan-normal seasons were similar for the three crops. However, in the 20 to 70 percent relative yield range, soil water depletion in the 0- to 120-cm profile was approximately 2.7 cm greater for wheat and sorghum than for soybeans. The lowest soil water contents measured in the 0-to 120-cm profile under prolonged stress were 1.3, 4.6, and 5.6 cm below -15 bars potential for soy-beans, grain sorghum and winter wheat, respectively. Based on depletion to below -15 bars, plant avail-able water exceeded the -1/3 to -15 bar range by 8.3 percent for soybeans to 35.7 percent for winter wheat. The relationship between soil water depletion and relative yields of grain sorghum obtained from a graded furrow study was similar to relation-ships previously obtained from level border studies. Results indicate that data obtained from level border plots can be applied directly to graded furrow irrigations on simi-lar soils in the Southern High Plains.

No-Till Seeding of Irrigated Sorghum Double Cropped after Wheat

ABSTRACT IRRIGATED grain sorghum was successfully no-till seeded into wheat residue immediately following wheat harvest in the Southern High Plains. Grain sorghum grown with clean tillage and seeding was grown for comparison. No-till seedlings generally emerged faster, grew taller, and matured up to 5 days earlier than controls. Grain yields for a 5-yr study averaged 5,690 kg/ha for no-till and 5,070 kg/ha for clean-till, a 12 percent increase. No-till required only one-fifth as much time between crops to prepare and plant a seedbed. No-till reduced fuel requirements, including harvest, by 55 percent.

Grain sorghum canopy temperature as influenced by clouds

Canopy temperature of irrigated grain sorghum [Sorghum bicolor (L.) Moench] was monitored using an infrared thermometer during short-term changes in solar radiation. Canopy temperature is defined as the blackbody temperature that would produce the same radiation level that enters the instrument field-of-view from the crop canopy. Canopy temperature fluctuations of 3° C within 3 min were observed. These fluctuations followed closely the fluctuation in solar radiation. Due to the sudden changes in canopy temperature caused by radiation changes, care should be taken when attempting to estimate canopy temperature using infrared thermometry on days of variable radiation. The data indicated that on the descent portion of a radiation change approximately 1 to 2 min were required for near steady-state canopy temperature. Less time was required for steady-state conditions on the ascent portion of a radiation change.