Evaluation of Teff, Lupins, Sorghum and Other

New Potential Dryland Crops in Northeastern Oregon

William Payne, Oregon State University Agronomist,
Columbia Basin Agricultural Research Center, Pendleton, Oregon

Because of growing economic and environmental concerns over traditional wheat-based cropping systems rotations, there has recently been heightened interest in alternative rotation crops in the inland Pacific Northwest. Research has shown for years that the winter wheat/summer fallow rotation, which constitutes the major cropping system in Northeastern Oregon, promotes soil organic matter decline and soil erosion. There is a growing perception that there is a need to move on to cropping rotations which reduce or eliminate fallow, while maintaining or perhaps even increasing profitability.

Among other things, an appropriate crop species for rotation with wheat must be adapted to local soil and weather conditions, economically viable in terms of price and market potential, and fit into management schemes that benefit the wheat crop. Because there exists genetic variability within a crop species for adaptability to biotic and abiotic constraints of a particular region, a range of varieties usually needs to be tested. Ideally, a plant breeder should be involved to help identify which variety is best suited for a specific cropping system. Cropping system components which need to be considered include residue, disease and weed management, and well as crop water supply. Finally, to be economically viable, an alternative crop must have a potential market. One therefore needs to have some information on such things as approximate market price, and potential market size.

The Pacific Northwest has a somewhat unusual weather pattern compared to most of the semi-arid world. One well known principal feature is that most rainfall comes during the winter months. Another important feature is the rapid transition from growing conditions that are cold and damp to those that are hot and dry. This is illustrated with daily temperature and daily

vapor pressure deficit values during a twenty year period (Fig. 1 and 2). Figure 1 also illustrates that temperatures during May of 1998 have rendered this season a particularly difficult for 'warm season' crops. Vapor pressure deficit, which is a measure of the difference between how much moisture the atmosphere can contain (which is determined by temperature) and how much it

does contain (i.e., atmospheric humidity) constitutes the most important driving force for the rate of crop transpiration and water evaporation from the soil. Vapor pressure deficit is inversely related to crop water-use efficiency. If the vapor pressure deficit doubles during the spring months in the PNW, crop water-use efficiency is halved.

In many respects, the early part of the spring is more suited to crops adapted to cooler and wetter climates, whereas the latter part and the summer months are more suited to "warm season" crops with good heat and drought tolerance. In order to be a successful alternative crop in the PNW, the former group needs to be harvested before heat and vapor pressure deficit become damaging, whereas the latter group needs on the one hand to be sown late enough that temperatures are sufficiently warm, but on the other hand before the seed bed is too dry for good emergence.

With these points in mind, we have this year begun evaluating experimental rotation crops for their suitability for annual rotation with winter wheat. For each species, market viability was tentatively assessed, and water use was being measured. Furthermore, for each species under consideration, we have obtained the active collaboration of a leading plant breeder. The crop species include currently being evaluated are white and narrow-leafed lupins, corn, sorghum, pearl millet, teff, pigeon peas, and soybeans. We have used small plot (120 ft2), on-station plot experiments as a cost-effective method of making preliminary evaluations. A brief description of each crop follows.

LUPINS

Lupins are self-pollinating, mostly indeterminate leguminous species that has been cultivated for several thousand years. The size of the area over which this species is naturally distributed, the diversity of soil and climatic conditions, and the range of uses for this species have resulted in a wide variability for most morphological characters, for seed size and composition, and for tolerance to stress, especially disease. Seed protein content ranges from 33 to 47%, according to genotype and location, and oil content varies from 6 to 13% .

Four species of the genus Lupinus (L. albus, L. angustifolius, L. luteus, L. mutabilis) are cultivated in the world for one or more of three main uses: i) human food, because of their high protein and oil contents; ii) green manure, contributing to an increase of organic matter content and soil nitrogen content; and iii) ruminant feed, either as green forage in the areas of traditional cultivation or, more and more, as grains introduced as protein supplements in the diets of ruminants. The potential market through industrial processing or through on-farm use is very large in Western Europe. The absence of alkaloid or trypsine inhibitors allow the grains to be used directly on poultry, cattle, and sheep farms either whole, cracked, or ground. Because of its agronomic characteristics, which include contribution of nitrogen and dry matter white lupin could contribute to the sustainability of the crop rotation.

White lupin originated in the Mediterranean and along the Nile valley. It was first introduced into the southeastern United States in the 1930's for use primarily as a plowdown green manure for succeeding crops. During the past 15 years, there has been renewed interest in white lupins in the northern Midwest and northeastern parts of the US, and in Canada.

The domesticated narrow-leafed lupin remains largely untested in the Pacific Northwest. This species, which is largely a product of Australian research, is grown on more than 3 million acres in Western Australia. The narrower leaf morphology of this lupin species ought to facilitate greater water-use efficiency and maintenance of cooler temperatures during hot, windy weather. This could be a useful trait in the Pacific Northwest because, similar to peas, pod set in lupin is deleteriously affected by high temperatures.

Seed protein content of lupin ranges from 33 to 47%, according to genotype and location, and oil content varies from 6 to 13%. The absence of alkaloid or trypsine inhibitors allow the grains to be used directly on poultry, cattle, and sheep farms either whole, cracked, or ground. Because of the high oil and protein content of lupin, the potential market through industrial processing or through on-farm use is very large. However, the international market for lupin will really take off if it can be used extensively as an industrial oil.

Major biotic constraints to lupin production include larvae (seed corn maggot) and fungus disease. Currently there are no insecticides labeled for use in lupin. Anthracnose, a seed-borne disease presenting itself very early in the cycle, is a major threat. Symptoms include cankers on the stems which curl and break. In addition to disease resistance, current breeding efforts

are being directed towards resistance to high pH, frost, and drought. Efforts are also directed towards the introduction of dwarfing and determinate genotypes to increase yield stability.

It has been estimated in Australia that a seed yield ratio of white lupin/winter wheat of 1/1.5 is likely to make white lupin competitive. Because of its contribution of nitrogen and dry matter to the soil, lupin could contribute to increased sustainability of crop systems.

SORGHUM

Sorghum (Sorghum vulgare, S. bicolor (L.)) is a common name for corn-like grasses native to Africa and Asia, where they have been cultivated since ancient times. Sorghum is cultivated worldwide for fodder, grain, and syrup production. Grassy sorghums, including Sudan grass, are widely grown for fodder and pasture. Sorghum cultivation for grain began in Egypt thousands of years ago. Today grain sorghums are the staple food for millions of people in China, India, and Africa.

Although sorghum was brought to the U.S. during early colonial days, it did not become an important crop until farming expanded into the drier regions, where it generally out-yielded other cereals. Today, nearly all of the varieties grown in the U.S. are dwarf types, with stems from 3 to 5 feet in height, that trace back to African origins. Grain sorghum in the US serves primarily as livestock feed, and is suitable for harvesting with combines.

Grain sorghum leaves are relatively broad, have numerous but small stomata, and are covered with a waxy bloom. Under moisture stress, leaves tend to roll along the midrib. These features afford the plant greater drought resistant and water-use efficiency than most other grain crops. Sorghum is much more heat- and drought- tolerant than corn. In India, Sudan, and along the Senegal river basin, sorghum is grown entirely on residual moisture.

Nearly all the sorghum grain consumed in the United States is used for livestock feed. Many years ago, older sorghum varieties contained high levels of tannin, rendering them unsuitable for feed. However, modern varieties no longer contain appreciable tannin levels. For feed use, sorghum grain should be ground for most classes of livestock, since the grains are small and relatively hard. In feeding value, sorghum is almost equal to kernel corn. Sorghum protein content is greater than that of corn, and about equal to that of wheat. It has less fat content than com but more than wheat. Sorghum generally sells at about 90% the price of corn.

Although most sorghum grain is consumed in the US as livestock food, there is nonetheless a potential export market for sorghum as food. Of the approximately 740 million bushels produced annually in 1966 and 1967, about one-third was exported--mainly to Japan, India and Europe. Most of that was probably used as food. For food use, the grain may be roughly ground and made into breadlike preparations, used after grinding and stewing as a mush or porridge, or made into flour for mixing with wheat flour for breads. Varieties with waxy endosperms are a source of starch having properties similar to tapioca. The grain is also a source of native beers, particularly in Africa.

Some quantities of grain sorghums go into industrial uses in the US. Starch is manufactured by a wet-milling process similar to that used for corn starch. The starch is then made into dextrose for use in foods. Starch from waxy sorghums is used in adhesives and for sizing paper and fabrics, also in the "mud" used in drilling for oil. The grain is also a source of grain- and butyl alcohol.

Most sorghums now being grown in this country are from hybrid seeds. Use of such seed, coupled with improved agronomic practices, have resulted in recent average yields which are more than double those being obtained from 1952 to 1956. In the Panhandle of Texas, the most profitable rotation is winter wheat-sorghum-fallow, which lends itself well to no-till systems.

The Pacific Northwest may have a comparative advantage for sorghum grain quality, because shatter cane is currently not a problem in the region. Based on this advantage, it is probably unwise to grow Sudan grass x hybrid crosses in the region, because they can cross with Johnson grass (Sorghum halepense) and Sudan grass to produce shatter cane. Birds are another potential biotic constraint to grain sorghum production.

PEARL MILLET

Pearl millet (Pennisetum glaucum) ranks as the world's fourth most important tropical food cereal, with 64 million acres currently grown. These are mostly in semi-arid Africa and India, where it is a staple food crop for human consumption. Modern pearl millet varieties are early maturing, and well adapted to drought and sandy acid soils of low fertility. Pearl millet is highly responsive to fertilizer and moisture on well drained soils. For PNW growing conditions, however, it is important to note that, traditionally, pearl millet has done poorly under conditions of low temperature or poorly drained soils.

Pearl millet was first grown as a summer pasture forage crop in the southeastern US in 1875. Until recently, its cultivation was restricted mostly to a hybrid forage crop on about 1.5 million acres. There is now, however, renewed interest in pearl millet as a grain crop. Most utilization research on pearl millet grain in the US is directed towards its use as a feed grain. Compared to corn, pearl millet is much more tolerant to heat and drought. Furthermore, pearl millet grain is higher in crude protein, and 40% higher in lysine and methionine. Substitution of pearl millet grain for corn therefore reduces the need for high protein feed ingredients and supplemental amino acids. The grain hybrid HGM 100 TM, from Tifton has been marketed since 1991. The grain is used in poultry and animal rations, and is currently sold at the same price as corn.

The grain filling period of pearl millet is shorter than that of grain sorghum, which may be of advantage in terminal drought situations. Some pearl millet varieties will mature before early sorghum grain hybrids, unless the growing season has below normal temperatures.

Grain breeding programs for pearl millet have been established at Kansas State University, USDA/ARS in Tifton, Georgia, and the University of NebraskaBLincoln. Most varieties developed in Nebraska and Kansas flower in middle to late August in west Nebraska. Photoperiod sensitivity is evident in some varieties, which results in delayed flowering in northern sites. Grain pearl millet normally flowers in 60-65 days after planting and requires 90-100 days to reach grain maturity.

Current agronomic research in the US has been conducted on planting date, row spacing, weed control, and fertilizer response. Breeding efforts are focused on regional adaptability. Pearl millet yields have exceeded sorghum in some locations, principally where the season is short, rainfall low, or soils sandy. Population improvement also continues for herbicide tolerance. There is currently no herbicide recommendation for pearl millet.

The chinch bug is the main insect pest of pearl millet. When this insect is present in a region, pearl millet should not be planted next to ripening wheat fields. Because of pearl millet's low tolerance to cool temperatures, poorly drained soils, and certain insects, it is doubtful that current varieties of pearl millet will become a viable rotation crop for wheat in the PNW.

TEFF

Teff [Eragrostis tef (Zucc.) Trotter], known commonly as love-grass, annual bunch grass, or warm-season annual bunch grass, was domesticated in Ethiopia between 4000 and 1000 BC. The word >teff' is thought to have originated from the Amharic word teffa which means lost, due to the extremely small size of the grain.

British colonial agronomists experimented with teff as a substitute crop for summer fallow in Kenya. Because of its relatively short cycle and shallow rooting depth, teff was found to offer substantial protection from soil and water erosion compared to fallow, but to extract relatively little soil water.

Teff is grown primarily as a cereal crop in Ethiopia. The grain is ground into flour, fermented, and made into a sour-dough type flat bread. Teff is eaten as porridge or used as an ingredient in home-brewed alcoholic drinks. Teff is also grown for livestock forage. In Ethiopia, teff straw from threshed grain is considered to be an excellent forage that is superior to straws from other cereal species. In the U.S., teff remains a largely experimental crop, with limited use as a flour by specialty mills. Small acreage of teff is grown for grain production and sold to Ethiopian restaurants (such as in Carlson, Idaho) or utilized as a late-planted livestock forage (such as in Larson, Minnesota). The nutritional value of teff grain is similar to the traditional cereals, but teff is considered to have excellent amino acid composition. Its lysine levels are higher than wheat or barley, and slightly less than rice or oats. Teff contains very little gluten, and is higher in several minerals than other cereals, particularly in iron.

Teff is classified as intermediate between tropical and temperate grasses. It is adapted to soil environments ranging from drought-prone to water-logged. Despite its small seed size, teff is an aggressive competitor once established. Maximum teff production occurs at altitudes of 1800B2100 m, and at growing season rainfall of 450B550 mm. Teff has a temperature range of 10B27°C. Teff is day length sensitive and flowers best during 12 hours of daylight.

PROSO MILLET

Proso millet, Panicum miliaceum (L.), is a warm season grass capable of producing seed 60 to 90 days after planting. It has been grown in dry zones of many countries of the world, including China, Afghanistan, Romania, Turkey and India. Currently proso is grown in the high plains of the US, where production has been quite variable. Acreage has been dependant upon survival of winter wheat, advent and demise of government programs, and market price. US acreage has averaged 200,000 acres. South Dakota and North Dakota were the largest producers until 1985, but since then Nebraska and Colorado have expanded to equal acreage.

Proso is used as bird and livestock feed in the US, and for livestock and human consumption in other countries of the world. Feed value of proso millet for cattle and swine is generally considered to be equal to that of grain sorghum. Some processing is necessary to crack the hard seed coat to allow for better digestion. The economics of raising proso millet for livestock feed depend on yield levels and production costs relative to other feed grains. Currently, proso brings approximately $5/bu, but the market is relatively small, and could probably easily be saturated.

Proso produces enough plant material to be considered a forage crop. It should be harvested soon after the seed begins to fill to avoid loss of seed during harvest. It has not been used extensively as forage because of pubescence on the stems and leaves. When forage is desired, farmers generally prefer foxtail millet.

In a crop rotation, proso can be used to gain an extra cash crop every three years in a wheat- proso-fallow rotation. It also can be grown as a cash crop when wheat acres are reduced by government programs to less than one-half of the total acres of the farm. Proso is a potential candidate for flex-cropping, because it can be planted late as a catch crop to replace winter wheat lost to freezing, wind erosion, drought or hail.

Proso is a very efficient user of soil water and can produce a grain crop on low rainfall. Studies at Akron, Colorado, indicate that proso begins producing grain after only 6 inches of total water use, whereas winter wheat requires at least 9 to 10 inches. Proso has a shallow rooting system limited to the upper 2 to 6 inches, and is one of the most efficient crops at removing moisture from the topsoil. It also is highly water-use efficient. Proso requires 270 lbs of water per lb of dry matter, compared to wheat, which requires 530/lb.

Although Proso was often thought to rely on summer rains and use very little stored subsoil moisture, Nebraska research suggests that soil water levels at planting may be used to predict proso grain yield with a high degree of success. This suggests that Proso may do well in the Mediterranean-like climate of the inland Pacific Northwest.

Proso fits in rotation with row crops and small grains. Proso can possibly replace summer fallow in a winter wheat-fallow rotations, which provides more surface cover and makes it easier to meet the requirements of conservation compliance.

PIGEON PEA

Pigeon pea (Cajanus cajan), known commonly as congo pea, red gram, non-eye pea, and dahl, is a vigorous, drought-tolerant legume widely grown in subtropical and tropical regions as an

edible and forage legume. It is one of the most common legumes of the subtropics because of its very wide adaptability. Pigeon pea is extremely tolerant to drought and heat. It possesses a deep taproot which well adapted to dryland conditions, because it can penetrate plough layers, and take up sparingly soluble sources of phosphate. Peas can be harvested in the dry stage and marketed as dried peas.

Pigeon pea varieties are classified as tree-type, tall or dwarf. Although it can be grown as tree cultures in the tropics, pigeon pea must be grown as an annual in most parts of the U.S. since plants are killed by freezing temperatures. In the US, it is grown as erect, short-lived shrubs, attaining a height of six to eight ft. Pigeon pea is deep rooted and drought resistant, growing especially well on semi-arid systems. It has poisonous roots, and therefore often planted as a hedge around some crops, such as cassava, to keep out mole rats.

Pigeon peas are commercially important in India, which imports 8,000 to 10,000 metric tons of peas per year. India's population, which is 80% vegetarian, comprises the world's largest legume- consuming market is projected to soon pass China as the world's most populated country. India cannot produce enough pigeon pea to satisfy internal demand. Pigeon pea is also gaining a niche market in the US because of its growing Indian population.

There is a potential market in the US for pigeon peas as fodder, because the pods, seeds and leaves are excellent fodder for cattle. It is also widely used for hay and silage (often with molasses), especially the small-seeded varieties. If cut for hay when the pods are well developed, it should be cut successively higher. The ground seeds can be incorporated as a source of protein in poultry rations.

CORN AND SOYBEANS

 

Two alternative crop species that are not new to the region, but are being re-evaluated in the light of recent genetic improvements, are soybeans and corn. Currently, four soybean varieties are being tested, one of which is very early. The hope is that it can flower and mature before the very hot and dry period during late July. Alternatively, very late varieties might be able to successfully flower and fill pods after this period, provided sufficient amounts of water reserves are available in the soil profile.

There are also four varieties of corn being tested, three of which have been the most successful varieties tested thus far in STEEP II experiments. The fourth is an early dwarf variety which has worked in other dry zones of the country, and which has the advantage that it can be planted and harvested using conventional drills and combines.

RESULTS

These preliminary data are presented to give an initial evaluation of whether any of these crops appear to have immediate- to medium-term potential as rotation crops on the one hand or, on the other hand, appear to have little potential and perhaps ought to be eliminated from further consideration at the end of this two year experiment. Nonetheless, they are preliminary data, and as such definite conclusions cannot be drawn from them. For some crops, yield and/or water-use data were not available as of this writing.

In general, for crops other than narrow leafed lupins, yields ranged from disappointing to disastrous (Table 1). It is probable that, at least in some cases, yields were hampered more by our unfamiliarity with the crop under these growing conditions than by poor suitability of the crop per se. This underscores the fact that, if any of these crops are to become viable alternative crops for rotation with wheat, further research will be required.

Table 1. Yield and soil profile water storage at harvest for several alternative crops at Moro and Pendleton, 1998. Numbers in parentheses indicate number of varieties tested.

Species

Grain Yield (lbs/acre)

Standard Dev.

(lbs/acre)

Water Stored at Harvest

(Inch)

Standard Dev.

(Inch)
Location Pendleton Moro Pendleton Moro Pendleton Moro Pendleton Moro
Sorghum (2)

1047

 

725

280

267

9.0

6.1

0.8

0.1
Corn (4)

1586

1046

301

239

9.0

6.2

0.8

0.4
Pearl millet (1)

303

192

110

29

10.0

6.8

1.0

0.6
Soybean (4)

306

149

175

55

8.2

6.4

0.6

0.5
Teff (2)

172

40

40

24

10.0

----

1.5

-----
Pigeonpea (1)

271

Deer

86

----

8.6

-----

0.5

------
Spring Wheat

-----

-----

-----

-----

6.4

5.5

1.2

0.1

Of the crops listed in Table 1, only sorghum and corn seemed to be close to achieving agronomically viable yields. For these crops, we can use water-use efficiency data from the literature to estimate how close we are to realizing genetically potential values, and how genetics and agronomy might contribute to closing existing gaps for these growing environments. For example, a globally accepted value for water-use efficiency of grain sorghum is 340 lbs acre-1 per inch of water used (corrected for regional atmospheric evaporative demand). Thus, for 16" of water use, one ought to be able to produce 5,440 lbs acre-1 of sorghum. The fact that we achieved much less than that value at Pendleton demonstrates that we have the wrong combination of genotype and agronomic package (seeding rate and date, fertilizer amount and application, etc., tillage system) for these growing conditions. Until we can approach this level of water-use efficiency, it is doubtful that sorghum will be commercially viable. For sorghum, a major problem appeared to be emergence from slightly crusted soils. This is a problem which has been successfully managed in Texas and elsewhere through a combination of breeding and tillage. In a major effort to address this, next spring we will conduct research under different tillage systems and planting dates on 50 sorghum varieties, including many from Nebraska and Texas which have been bred for cold as well as drought tolerance.

Despite the low yields for pigeonpea and soybeans, the study demonstrated that both these species were able to emerge during the cool spring, and to survive the dry and hot period in late July and August. At Pendleton, soybeans were able to extract greater amounts of water than either sorghum or corn, suggesting that perhaps later maturing varieties could be used. Field data from an unrelated experiment by a local grower seemed to also suggest this.

Pigeon pea has uncharacteristically small size, poor groundcover and an apparent photoperiod response, suggesting that this particular variety was unsuited to our conditions. Nonetheless, the crop continued to flower and its leaves remained turgid throughout the hot season, suggesting there may still be scope for considerable improvement with this crop, at least in the Pendleton area. Yield data were not available from Moro because deer ate the plants.

Teff and pearl millet did particularly poorly at both Pendleton and Moro. Given the cool nights and poorly drained soils (relative to Africa and Indians soils on which it is normally grown), this did seem surprising in the case of pearl millet. For teff, much of the problem may have been due to our unfamiliarity. The extremely small seeds made this sowing and threshing of crop very difficult. Compared to sorghum and corn, it did extract less water, but this may have been related to its poor stand.

Yields were disastrously low for white lupins at both Pendleton and Moro. Although plants flowered regularly, pod set was very poor, perhaps due to hot temperatures. However, the narrow-leafed lupin yields were very encouraging (Table 2). In particular, there does appear to be good agronomic potential for Merrit, the earliest variety. An interesting aspect of these data is that this crop performed better in the drier area.

We feel optimistic enough about these data to begin on-farm testing next year, and are ordering seeds of even newer and earlier varieties from Australia.

Table 2. Yield (lbs/acre) of four varieties of narrow leafed lupins at Moro and Pendleton. Varieties range from earliest on the left to latest on the right.

Location Merrit Yorrel Danja Chitick
Moro

1237

702

569

34

Pendleton

778

488

303

1


 

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