Dan Putnam

University of California, Davis | UCD · Department of Plant Sciences

Forage systems in arid zones are characterized primarily by the limitation of water, thus, forage systems can be divided into two major categories: rainfed forages and irrigated forages. These two distinct forage systems are the basis of several important economic sectors, which produce a range of products for different markets, both export and dom...

It is well known that California experiences dramatic swings in precipitation that are difficult to predict and challenging to agriculture. In times of drought, groundwater serves as a crucial savings account that is heavily relied upon. However, few tools exist to proactively refill this crucial reserve in wet years. We explored the idea of intent...

Background: Lignin is a complex, phenolic polymer found in plant cell walls that is essential for mechanical support, water and mineral transport, and defense in vascular plants. Over ten different enzymes play a role in the synthesis of lignin in plants. Suppression of any one enzyme or combinations of these enzymes may change the concentration a...

In California, alfalfa is grown on a large area ranging between 325,000 and 410,000 hectares and ranks among the thirstiest crops. While the hay production industry is often scrutinized for the large usage of the state’s agricultural water, alfalfa is a crucial feed-supplier for the livestock and dairy sectors, which rank among the most profitable...

The introduction of genetically engineered (GE) alfalfa requires a mechanism for producers to successfully grow and market alfalfa (Medicago sativa L.) hay destined for GE‐sensitive markets such as organic and export. A process of coexistence includes elements of respect for diverse agricultural systems, improved communication, scientific knowledge...

This study was carried out to develop a model to explore the economic viability of subsurface drip irrigation (SDI) for alfalfa production in the major alfalfa production regions of California. Data from previously published studies on alfalfa under drip irrigation were applied to establish the relationship between hay yield and seasonal water use....

The productivity and persistence of perennial grass species and individual cultivars of tall fescue [Schedonorus arundinaceus (Schreb.) Dumort., nom. cons] and orchardgrass (Dactylis glomerata L.) were evaluated in response to early-season irrigation termination. Twenty-five perennial grass species/cultivars were evaluated under three irrigation re...

Climate change, which is currently characterized by increased atmospheric CO 2, rising temperature , and altered pattern of precipitation, is affecting agricultural productivity. Rising temperatures and shifting precipitation patterns will alter the ability to meet crop water requirements, water availability, crop productivity, and costs of water a...

The nutritional value of various crops can be improved by engineering plants to produce high levels of proteins. For example, because methionine deficiency limits the protein quality of Medicago Sativa (alfalfa) forage, producing alfalfa plants that accumulate high levels of a methionine-rich protein could increase the nutritional value of that cro...

Abstract Text: Previous research on nitrate (NO3-) supplementation in dairy cattle diets demonstrated that NO3- is effective in decreasing methane (CH4) production; however, it also induced nitrous oxide (N2O) production under the rumen simulated conditions. One possible strategy to mitigate concomitant N2O emission is by enhancing the activity of...

Sustainable and environmentally benign switchgrass production systems need to be developed for switchgrass to become a large-scale dedicated energy crop. An experiment was conducted in California from 2009 to 2011 to determine the sustainability of low- and high-input irrigated switchgrass systems as a function of yield, irrigation requirement, cro...

Forages are a large component of agroecosystems worldwide, and contribute significantly to world food production. A wide diversity of plants are cultivated as forages, from succulent legumes (alfalfa and clovers), to cool- and warm-season perennial grasses and annual crops such as corn and oats. Forages may be harvested as hay, grazed pasture, rang...

Climate trends and foreign oil dependency have led to a search for alternative sources of energy, such as biomass energy crops. Switchgrass (Panicum virgatum L.) has shown promise as a high yielding energy crop in the United States. The objectives of this study were to evaluate cultivar Trailblazer switchgrass adaptability, biomass yield potential,...

The production potential of switchgrass (Panicum virgatum L.) has not been estimated in a Mediterranean climate on a regional basis and its economic and environmental contribution as a biofuel crop remains unknown. The objectives of the study were to calibrate and validate a biogeochemical model, DAYCENT, and to predict the biomass yield potential...

Altering lignin biosynthesis through genetic approaches impacts the digestibility of alfalfa (Medicago sativa L.) in ruminant systems. Field-grown alfalfa lines engineered for reduced caffeic acid 3-O-ethyltransferase (COMT), caffeoyl CoA 3-O-methyltransferase (CCOMT), and their respective non-transformed controls were harvested four times, and sam...

Ethanol use in California is expected to rise to 1.62 billion gallons per year in 2012, more than 90% of which will be trucked or shipped into the state. Switchgrass, a nonnative grass common in other states, has been identified as a possible high-yielding biomass crop for the production of cellulosic ethanol. The productivity of the two main ecoty...

Although there are many influences on crop productivity, selection of alfalfa (Medicago sativa) cultivar sets the upper genetic potential for yield and other performance traits. Variety testing programs, such a those at the University of California provide a scientific approach to selection by growers and seed companies, but variety selection is st...

In recent years, there has been a trend in California from harvesting hay in small hay bales of about 125 pounds to very large bales of 1,300 pounds or more. This shift is driven by both production considerations and the preferences of some consumers, but has significant implications for the hay market and its many consumer segments. We conducted a...

Evapotranspiration (ET) of fully-irrigated and deficit-irrigated (no irrigation in July, August, and September) was measured in five alfalfa fields at various locations throughout California. Seasonal ET ranged from 838 to 1,651 mm, which differed from historical seasonal ET. Deficit irrigation reduced ET, but the ET difference between fully-irriga...

The loss of protein by plant proteases during ensiling of forage legumes reduces forage quality, causing both lower animal performance and potential by negatively impacting on nitrogen loss to the environment. Polyphenol oxidase (PPO) enzyme catalyzes the oxidation of phenolic compounds to o-quinones, these easily react with amino acids, proteins o...

The export of N as a pollutant from dairies or other animal facilities can be reduced by land application programs that synchronize plant-available soil N with crop N demand. A simple, but reasonable, representation of N content over time by small grain forages is needed to assist in management of manures in dairy forage systems. Our objective in t...

Many alfalfa (Medicago sativa L.) fields are sprayed each year with insecticides to control Egyptian alfalfa weevil (Hypera brunneipennis) and the alfalfa weevil (Hypera postica). Overseeding various species of legumes and grasses into established alfalfa has been proposed as a method to mitigate weevil damage without insecticides. Established fiel...

Alfalfa is California’s single largest agricultural water user due to its large acreage and long growing season. As a result, interest exists in midsummer deficit irrigation (no irrigation in July, August, and September) of alfalfa in water-rich areas to provide water for water-short areas with the amount of transferred water equal to the differenc...

Alfalfa protein is poorly utilised by ruminants due to its rapid degradation in rumen. The objective of the study was to assess the influence of spraying tannic acid (TA) on chopped alfalfa hay on in vitro rumen fermentation and nitrogen (N) retention by sheep. Alfalfa hay with and without TA was fed to sheep to determine nutrient digestibility and...

Tannins may reduce rumen degradability of protein, increase the proportion of feed protein reaching the lower digestive tract for enzymatic digestion and thereby increase the efficiency of protein utilization. The objective was to assess the effects of different types and levels of tannins on rumen in vitro gas production and its kinetics, in vitro...

Evapotranspiration (ET) of fully-irrigated and deficit-irrigated (no irrigation in July, August, and September) was measured in five alfalfa fields at various locations throughout California. Seasonal ET ranged from 33 to 58 inches, which differed from historical seasonal ET. Deficit irrigation reduced ET, but the ET difference between fully-irriga...

Evapotranspiration (ET) of fully irrigated and deficit irrigated (no irrigation in July, August, and September) was measured in four commercial alfalfa fields with the eddy covariance (EC) and surface renewal (SR) energy balance methods. Both EC and SR methods were used in the fully irrigated part of the fields, while the SR method only was used in...

Alfalfa ET from two opposite sections of a 16.2 ha field was estimated using: 1) soil moisture depletion between irrigations from neutron backscatter (NP) and Enviroscan Capacitance (ES) probes, 2) surface renewal (SR) analysis of sensible heat flux into and out of the crop and 3) a fitted yield by ET production function and the yield decrease asso...

Alfalfa is California's single largest agricultural water user due to its large acreage and long growing season, using 490,000 to 677,000ha-m of water each year. Because of the high water usage, interest exists in midsummer deficit irrigation (no irrigation in July, August, and September) of alfalfa to provide water for transfer from water-rich are...

Unfortunately, yield and quality are generally inversely related. This presents a real dilemma for growers who seek to maximize both yield and quality. Frequent cutting to produce high-quality hay results in low yield, whereas, a long interval between cuts increases yield but quality is reduced. The best cutting strategy ("go for yield" or "go for...

Forage quality testing defines the language of value between the dairy and forage sector. From a nutritionist's viewpoint, forage quality consists of many analyses that, together, provide a prediction of performance in a balanced ration for the dairy cow. Marketing systems, on the other hand, require a few simple criteria that can be related to val...

components. In dense populations, many kernels may not develop. This occurs in some genotypes due to poor Plants grown at noncompetitive densities (isolated plants) can be pollination resulting from a delayed silking period com- yield and its components of plants in these densities with those of isolated plants. The highest grain yield in all exper...

Water transfers from agriculture have largely occurred through fallowing of agricultural land. However, this type of transfer has negative consequences economically, socially, and environmentally. A partial solution to water shortages in drought years could be voluntary transfers of a portion of irrigation water used in alfalfa production in drough...

sample when the alfalfa reaches the maturity stage of 1/10th bloom. When this level was established, the common practice was to harvest at 10% bloom. However, with the market incentive for higher quality, growers rarely let their hay mature beyond the bud stage. The literature suggests that the tissue values be increased by 10% if taken before the...

The interactions between cutting schedule and variety were examined in a 3-year study with 18 varieties and 3 cutting schedules on the UC Davis campus. Cutting intervals ranging from 24 days to 33 days between cuts generally had a stronger influence on yield and quality than did variety. Early cutting schedules resulted in significantly lower yield...

An objective of every alfalfa grower is to maximize both yield and quality to receive optimum returns without jeopardizing stand life. However, yield and quality are typically inversely related; the highest quality is almost never associated with the highest yield. Since quality affects price and animal production, growers must discover a compromis...

While alfalfa provides many positive attributes contributing to environmental health, several issues associated with water quality have become apparent in recent years. Although alfalfa is not highly pesticide intensive, several pesticides have been implicated in water quality contamination. Specifically, the potential for contamination of surface...

The alfalfa weevil complex is the most severe insect pest of alfalfa in California. Because weevil larvae are the first insect pests of the production year to require management actions consideration of possible effects on pest management for the rest of the season must be made. Organophosphate and carbamate insecticides have provided acceptable we...

Alfalfa uses approximately 18.7% the state's agricultural water, a larger percentage than any other single crop. Reduced water availability for agriculture is probable in the coming years in many areas of the state, driven by urbanization and environmental demands. Therefore, examination of deficit irrigation strategies is warranted. More informati...

Harvest timing has a profound effect on the yield and forage quality of alfalfa hay. Early harvest results in low yield but high forage quality and price, while delayed harvest increases yield but reduces forage quality and price. Since gross revenue is a function of both yield and price, it is important for growers to select the optimum cutting sc...

Some insecticides used for controlling Egyptian alfalfa weevil have been detected in California's surface waters and are of concern, due to their impact on water quality and toxicity to some aquatic life. To assess the impact of insecticide choice on water quality, we collected tail-water samples from on-farm alfalfa sites in the northern Sacrament...

The Egyptian alfalfa weevil (alfalfa weevil in some areas) during most years is the most severe insect pest of alfalfa in California. These pests feed on alfalfa leaflets and stems, reducing hay yields. Several insecticides provide acceptable control of this pest. Historically, product choice has been driven by efficacy on the pest, cost, presence...

The "optimal cutting schedule" for alfalfa hay is described as a function of the trade-off between rising yield and falling quality of alfalfa over time and the local market prices being offered for different qualities of hay during the harvest season. Field test results quantify the yield/quality tradeoff for a California case study. A general dec...

Generalized growth curves for yield and quality changes over time were developed for three California locations (the Intermountain region and the Sacramento and San Joaquin Valleys). Daily rates in change among the seasons and locations differed due to temperature and weather variations. Yield increased and quality decreased more rapidly in the lat...

Accurate forage analysis that is representative of a lot of hay is needed by nutritionists for ration balancing and by buyers and sellers of hay in determining a price for the crop. A lot of hay is generally considered to be hay from the same cutting, field, species, variety, maturity stage and curing conditions that has been stored under similar c...

Forages dominate the low-desert agricultural landscape. Competition for water resources is intensifying in desert regions at the same time that demand for high-quality forage crops is increasing. California is a forage-deficit state and is likely to remain so in the future. To improve and sustain forage production in the desert, research and educat...

Because the neurotoxic common vetch (Vicia sativa L.) legume seems to have come into some use in man's diet, we have investigated, using Pico-Tag analysis, the stability of the vetch neurotoxins to cooking. When heated in water at 100 °C for 3 h, γ-glutamyl-β-cyanoalanine (γ-gluBCA) cyclized extensively to form pyroglutamic acid and β-cyanoalanine...

Increased world demand for high-quality edible oil requires agronomic practices that increase oilseed yields with minimal environmental impact. We hypothesized that strip intercrops of canola (Brassica napus L.) and soybean [Glycine max (L.) Merr.] would increase seed, oil, and protein yields compared with sole crops. Canola (cv. Global) was grown...

Grain of 21Amaranthus accessions (eight species) was analyzed for crude fat, fatty acid profiles (FAP), and vitamin E (tocopherols and tocotrienols). Contents of (1→3), (1→4) β-glucan were determined in 12 accessions (four species), and trypsin inhibitor activity (TIA) in 20 accessions (six species). FAP and vitamin E profiles were compared to thos...

Fatty acid profiles (FAP), tocopherol (T), and tocotrienol (T3) contents, total lipid contents, and trypsin inhibitor activity were quantitated from thirteen accessions of camelina (Camelina sativa L. Crantz), a little-known oilseed. Camelina seeds of ten accessions were also assayed for ß-glucans. FAP (%) of camelina oils were: oleic (14.1 to 19.5...

Vitamin E isomers are important antioxidants, but their variation is poorly documented in pseduocereal grains such as amaranths. Using normal-phase, high-performance liquid chromatography with fluorescence detection, seeds of thirteen amaranth (Amaranthus cruentus L.,A. hypochondriacus L.) accessions were surveyed for the composition of tocols. The...

Three experiments were conducted to determine optimal substitution of lupin for soybean meal in dairy cattle diets; the effects of whole versus ground lupins and the effects of whole lupins versus whole soybeans on milk production were examined. In the first experiment, 57 cows were assigned randomly to treatments in blocks of five by calving order...

Understanding the agronomic importance of planting date and cold temperatures during germination may lead to the development of better management strategies for spring-sown white lupin (Lupinus albus L.). We conducted two experiments to determine optimum planting dates for spring-sown white lupin and to determine the effect of vernalization on plan...

Variation in seed yield and protein levels of sweet white lupin (Lupinus albus L. cv. Ultra) in the North Central USA has limited production of the crop in this region. Poor N nutrition from biological or exogenous sources may be one of the causes of this variation. Studies were conducted under irrigation in 1988, 1989, and 1990 at Becker, MN, on a...

Timing of N uptake and N 2 fixation may be important determinants of yield and seed N concentration in spring sown white lupine ( lupinus albus L.). This study was initiated to determine N 2 fixation, N and dry matter (DM) accumulation and distribution patterns, and nodulation as influenced by Bradyrhizobium sp. ( lupinus ) inoculation and N fertil...

The following three articles fall into a new and distinct category of contributions published in the Journal of Natural Resources and Life Sciences Education. They are called Case Study articles. Interest in providing problem-solving and decision-making experiences in education has sparked interest in the adaptation of decision cases for publicatio...

When grown on sandy soil, spring-seeded sweet white lupin (Lupinus albus L.) is usually subject to moisture stress. Late-germinating broadleaf weeds also compete with the crop and reduce yields. The objectives of this study were to determine the effects of five irrigation levels, two row spacings (15 and 76 cm), and late-germinating weeds on lupin...

Two intercrop patterns and sole crops of mustard (Brassica hirta Moench) and sunflower (Helianthus annuus L.) were planted in 1988 and 1989 on a Waukegan silt loam soil (fine-silty over sandy or sandyskeletal, mixed, mesic Typic Hapludoll) at Rosemount, MN, to examine mechanisms for overyielding [Land Equivalent Ratio (LER) > 1.0] in this intercrop...

Apios americana Medikus (apios) is a wild tuberous legume with potential as a crop plant. Five apios accessions were grown in sand culture in two greenhouse experiments to examine the effect of N fertilization and inoculation with Bradyrhizobium japonicum on yield and plant characteristics. A common soybean B. japonicum strain (USDA76) was applied...

If corn-soyabean intercrops are to replace corn grown alone, maintenance of yield and improvements in forage quality are important. Total yields and inter-crop competition in corn-soyabean intercropping experiments have been discussed previously (Putnam et al., 1985). In Part II yield composition, components and protein content are presented for in...

Intercropped corn and soyabean were grown in a randomized block design (RBD) and a systematic design (SD) in 1981 and 1982 to evaluate total yield, yield complementarity, crop competition and land-use efficiency as affected by corn and soyabean densities. In the RBD, three corn density treatments were applied to corn–corn–soyabean–soyabean, corn–co...

Corn (Zea mays L.) and soybean (Glycine max L. Merr.) were intercropped in various planting patterns in 1980, 1981, and 1982 on a Hadley fine sandy loam (coarse-silty, mixed, nonacid, mesic Typic Udifluvent) to determine if corn:soybean mixtures might provide silage superior to pure corn for ruminants. All but one of the intercrop planting patterns...

Choosing an alfalfa variety is arguably one of the most important decisions to make in an alfalfa operation. Variety selection impacts yield, forage quality, pest resistance and the life of a stand. The consequences of a poor decision last for years after establishment. Poor stand persistence can increase stand establishment costs (stands must be r...

There have been more than ten years of research experience and six years of grower experience with glyphosate-resistant (Roundup-Ready or RR) alfalfa to date. Here, we discuss the technical experiences with this technology, performance, and several of the positive and negative aspects. The information presented reflects grower views as well as rese...

Roundup-Ready® alfalfa was released in June of 2005, the first trait to be commercialized in alfalfa (Medicago sativa L.) using biotechnology. Traditional alfalfa varieties will likely be grown in close proximity to these new biotech varieties. While most users will probably not be sensitive to the presence of these varieties, other markets (partic...

A key question with regards to the introduction (and later suspension) of Roundup Ready trait in alfalfa is whether this technology would permanently harm those growers who did not wish to adapt this technology. The key concern is the possibility of gene flow that would contaminate GE sensitive crops (primarily organic and export growers) to the po...

In low price years like 2009, alfalfa growers scramble to find ways to improve profitability and often consider reducing inputs. However, many inputs are closely linked to yield or forage quality and cutting back could reduce overall profitability. Here, we consider several of the inputs where it may be feasible to cut costs and alternatively ident...

Forage quality has a large impact on market price and profitability. Nationwide, the marketing systems of Total Digestible Nutrients (TDN) and Relative Feed Value (RFV) are primarily 'fiber-based' marketing systems, since they depend upon Acid Detergent Fiber (ADF) and Neutral Detergent Fiber (NDF) lab measurements. Average change in California mar...

Several important benefits have been described for alfalfa. These are its rich habitat for wildlife, soil improving characteristics, N 2 fixation, its abilities to trap sediments and prevent water and air pollution, take up nitrate pollutants, provide an insectary for diverse beneficial insects, as well as to provide open space for aesthetic reason...

A range of alternative annual forage crops that could be grown in California are reviewed. We have grouped these into three general categories, fall-seeded annual cereals and grasses, fall seeded annual legumes, and summer annuals (excluding corn, which is covered elsewhere in this proceedings). This review is not comprehensive, but provides an ove...

Overseeding another forage species into a depleted alfalfa stand can extend stand life and improve the yield and marketability of the hay. Potential overseeded forage species include annual and perennial grasses and legumes. The species selected for overseeding can affect yield, forage quality, and the suitability of the forage for the end market....

The alfalfa stem nematode is the most serious nematode pest of alfalfa in the United States, causing serious yield, forage quality, and stand losses in infected fields to seedling as well as established stands. However, in recent years this pest was not a major concern to California growers as it was only occasionally found in alfalfa fields. Then,...

We determined the change in forage quality of two reduced lignin transgenic alfalfa (Medicago sativa L.) populations, compared to appropriate controls and grown in diverse environments. Harvests were taken beginning at late vegetative stage and continued at 5 day intervals for 5 total harvests. Forage samples were analyzed for crude protein, neutra...

About 40% of the alfalfa hay in the United States is produced in the 11 western US states of Arizona, California, Colorado, Idaho, Montana, Nevada, New Mexico, Oregon, Utah, Washington, and Wyoming. This region also supplies the vast majority of the seed for the nation's alfalfa plantings, and it contributes significantly to exports of alfalfa hay...

Alfalfa harvest timing has a profound effect on forage yield and quality, as well as profitability. Unfortunately, yield and quality are inversely related. Yield increases but quality decreases as harvest is postponed. Producers must make the decision whether to aim for high forage quality to receive the premium price or to maximize yield but recei...