HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Abstract Figures Only Full Text (PDF) Free Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Hayes, R. Articles by Singh, S. P. Search for Related Content PubMed Articles by Hayes, R. Articles by Singh, S. P. Agricola Articles by Hayes, R. Articles by Singh, S. P. Related Collections Other Legumes Crop Rotation Systems Other Cropping Systems

Legumes

Response of Cultivars of Race Durango to Continual Dry Bean Versus Rotational Production Systems

Univ. of Idaho, 3793 N 3600E, Kimberly, ID 83341-5076

^* Corresponding author (singh{at}kimberly.uidaho.edu)

	ABSTRACT

TOP ABSTRACT INTRODUCTION MATERIALS AND METHODS RESULTS AND DISCUSSION REFERENCES

 
Continual dry bean (CB, Phaseolus vulgaris L.) production in the same field for 2 or more consecutive years is common worldwide. However, the effects on and performance of dry bean cultivars in the CB production system is not known. The objectives of this research were to (i) determine effects of the CB production system on seed yield, seed weight, and days to maturity of race Durango cultivars; (ii) determine the correlations for those three traits between the CB and rotational production (RP) systems; and (iii) identify superior cultivars within and across both production systems. Medium-sized (25–40 g 100 seed^–1) cultivars of great northern (8), pink (3), pinto (9), and red (5) of race Durango released between 1932 and 1998 were evaluated from 1999 to 2001 in a field that had been under 50 yr of CB production at the University of Idaho, Kimberly Research and Extension Center. Concurrently, they were evaluated under the standard RP system. The cultivar effects and cultivar x year interaction effects were significant (P < 0.01) for seed yield, seed weight, and days to maturity in both production systems. Continual dry bean production reduced mean seed yield by 68%, seed weight by 11%, and days to maturity by 6 d. Large differences among cultivars existed within and between market classes in both production systems. On average, great northern and pinto cultivars had the greatest reduction (71%) and pink (56%) followed by red (66%) cultivars had the least reduction in seed yield due to CB production. Cultivars UI 537, UI 239, Viva, and Harold had the highest levels of resistance to CB production. Despite significant (P < 0.01) positive phenotypic correlation between the two production systems for seed yield (r² = 0.70), seed weight (r² = 0.90), and days to maturity (r² = 0.67), testing of dry bean cultivars using both production systems is suggested for identification of superior cultivars to be grown either within or across production systems.

Abbreviations: CB, continual dry bean production • CBI, continual dry bean production intensity index • CSI, continual dry bean production susceptibility index • PR, percent reduction in seed yield due to continual dry bean production • RP, rotational production system • QTL, quantitative trait loci

Response of Cultivars of Race Durango to Continual Dry Bean Versus Rotational Production Systems

Univ. of Idaho, 3793 N 3600E, Kimberly, ID 83341-5076

^* Corresponding author (singh{at}kimberly.uidaho.edu)

Received for publication October 30, 2006.
Continual dry bean (CB, Phaseolus vulgaris L.) production in the same field for 2 or more consecutive years is common worldwide. However, the effects on and performance of dry bean cultivars in the CB production system is not known. The objectives of this research were to (i) determine effects of the CB production system on seed yield, seed weight, and days to maturity of race Durango cultivars; (ii) determine the correlations for those three traits between the CB and rotational production (RP) systems; and (iii) identify superior cultivars within and across both production systems. Medium-sized (25–40 g 100 seed^–1) cultivars of great northern (8), pink (3), pinto (9), and red (5) of race Durango released between 1932 and 1998 were evaluated from 1999 to 2001 in a field that had been under 50 yr of CB production at the University of Idaho, Kimberly Research and Extension Center. Concurrently, they were evaluated under the standard RP system. The cultivar effects and cultivar x year interaction effects were significant (P < 0.01) for seed yield, seed weight, and days to maturity in both production systems. Continual dry bean production reduced mean seed yield by 68%, seed weight by 11%, and days to maturity by 6 d. Large differences among cultivars existed within and between market classes in both production systems. On average, great northern and pinto cultivars had the greatest reduction (71%) and pink (56%) followed by red (66%) cultivars had the least reduction in seed yield due to CB production. Cultivars UI 537, UI 239, Viva, and Harold had the highest levels of resistance to CB production. Despite significant (P < 0.01) positive phenotypic correlation between the two production systems for seed yield (r² = 0.70), seed weight (r² = 0.90), and days to maturity (r² = 0.67), testing of dry bean cultivars using both production systems is suggested for identification of superior cultivars to be grown either within or across production systems.

Abbreviations: CB, continual dry bean production • CBI, continual dry bean production intensity index • CSI, continual dry bean production susceptibility index • PR, percent reduction in seed yield due to continual dry bean production • RP, rotational production system • QTL, quantitative trait loci

	INTRODUCTION

TOP ABSTRACT INTRODUCTION MATERIALS AND METHODS RESULTS AND DISCUSSION REFERENCES

 
DRY BEAN is grown in diverse production systems worldwide. These systems vary from the monoculture system to various forms of inter-cropping, mixed-cropping, and relay-cropping systems with different annual and/or perennial species (Singh, 1992; Woolley et al., 1991). Various forms of intercropping are practiced in Latin America, Africa, and other regions of the world where farmers have relatively small land holdings and often grow two or more crops together in the same field either part of the time or throughout the entire production season. For example, the relay cropping of dry bean is common in Latin America where corn (Zea mays L.) often is planted first with or without nonclimbing or semi-climbing dry bean, followed by a climbing dry bean cultivar late in the season when ears on the corn plant are fully developed. In this inter-crop followed by relay-crop type system, farmers maximize land usage and try to assure the year-round supply of food, feed, fiber, and fuel. These traditional production systems also are known to conserve soil fertility and moisture, and minimize soil erosion. Monoculture dry or green bean production predominates in large, fully or partially mechanized farms in the more affluent regions of countries such as Argentina, central and southern Brazil, Canada, and the USA. In monoculture production systems, short to long rotations are used with dry bean grown only once in 2 to 7 yr. However, use of short rotation (i.e., dry bean planted twice in the same field in <3 yr) and CB production for 2 or more years in the same field is a common production system worldwide. This system is often used when dry bean prices are high and/or farmers are not able to accommodate dry bean within the standard RP systems. In countries such as Argentina, Bolivia, and Brazil, where some deforestation is still occurring and newly cleared land is being brought into cultivation, CB production, at least for the first few years, is common. Also, farmers are sometimes forced to CB production because there is a lack of other economically viable options. The many benefits of crop rotation include minimizing the build up of diseases, insect pests, and weeds, and improving soil fertility, water holding capacity, yield, and nutritional quality are well known. In contrast, knowledge regarding the effect of CB production on seed yield and other traits, and the response of dry bean cultivars to CB production is lacking.

Dry bean was introduced in the western USA from Mexico (Gentry, 1969; Kaplan, 1956; Kaplan and Lynch, 1999). The Native Americans grew dry bean in dryland or rainfed, low-input subsistence production systems for millennia. Since the advent of irrigation systems in the first half of the 20th century in the western USA, dry bean production has occurred in well tilled, irrigated, and fertilized soils often using the RP systems. Thus, major factors contributing to higher production costs of dry bean include the use of pesticides, fertilizers, water, and farm machinery. These factors have been shown to have adverse effects on fresh water resources, ecosystems, and cause increased soil erosion. As these environmental issues increase in importance, it must be recognized that most dry bean breeding since the turn of the 20th century until now has been conducted using intensively managed RP systems. Thus, it is not known if favorable, environment-sensitive genes and quantitative trait loci (QTL) that might have existed in dry bean landraces grown by Native Americans and early settlers to resist soil compaction, drought, soil mineral deficiencies, and to compete with weeds exist in the modern cultivars.

Dry bean has been grown continuously in a field at the University of Idaho, Kimberly Research and Extension Center since the farm was acquired in 1950 (Singh et al., 2001a). Because soil in this field is compacted, water holding capacity and infiltration are reduced creating a stressful environment for growth and development of the common bean. Therefore, this field is unique for production systems studies, comparison of cultivars developed over time, and breeding cultivars for sustainable dry bean production systems. The objectives of this research were to (i) determine the effects of CB production on seed yield, seed weight, and days to maturity of 25 race Durango dry bean cultivars released between 1932 and 1998; (ii) determine correlation for the three traits between the CB and RP systems; and (iii) identify superior cultivars within and across both production systems.

	MATERIALS AND METHODS

TOP ABSTRACT INTRODUCTION MATERIALS AND METHODS RESULTS AND DISCUSSION REFERENCES

 
Eight medium-sized (25–40 g 100 seed^–1) great northern, three pink, nine pinto, and five red bean cultivars released between 1932 and 1998 were evaluated in the field that had been under CB production for the past 50 yr. These cultivars predominantly possessed characteristics of the race Durango (synonymous with Gene Pool 5, Singh, 1989) that originated in the semiarid and arid central highlands of Mexico (Singh et al., 1991). These 25 cultivars also were evaluated in adjacent fields (<15 m distance) that had been under a crop rotation system. An average of 4-yr of crop rotation are popular in southern Idaho [e.g., (3 yr alfalfa–dry bean)–(small grain–sugar beet or potato–small grain–dry bean)–(3 yr alfalfa–small grain–dry bean)]. These experiments were conducted at the University of Idaho, Kimberly Research and Extension Center from 1999 to 2001. Pre-plant soil samples were taken for chemical and physical analyses and herbicides [Sonalan (ethalfluralin)] at 3.5 L ha^–1 were incorporated 10 to 12 d before planting. Despite the fact that no apparent deficiencies of any nutrient was found, plots were fertilized each year with an average of 200 kg ha^–1 of 11 N: 52 P: 0 K 2 wk before planting, a practice that is commonly done in the region to minimize unexpected soil heterogeneity and facilitate optimum plant growth. In addition, the CB field was deep plowed in 2001. A randomized complete block design with four replicates was used in each production system. Each plot consisted of four rows, each 5.5 m long spaced 0.56 m apart. Twenty-five seeds per linear meter were planted. Six surface-furrow or gravity irrigations (approximately 70 mm water irrigation^–1) were applied during the growing season in both fields. Two cultivations during the vegetative growth period and hand weeding were used to minimize soil compaction and to control weeds.

Growth habit was recorded during flowering and verified near physiological maturity when approximately 95% pods had turned from green to tan or yellowish-brown according to Singh (1982). Also, number of days from planting to physiological maturity was recorded. Seed yield (kg ha^–1) measurements were collected from the two center rows of each plot that were allowed to field dry after they were cut, threshed 8 to 10 d later, cleaned, and weighed after 8 to 10 wk of storage in a heated room (24°C constant temperature) when seed moisture had stabilized at 12% by weight. At that time, 100-seed weight (g) was recorded. All data for each production system were analyzed separately using a mixed model (McIntosh, 1983) that had cultivars as fixed effects and years and replicates random effects. Phenotypic correlation coefficients between the two production systems were determined for seed yield, seed weight, and days to maturity. Furthermore, formulae from Fischer and Maurer (1978) were adopted to determine the CB production intensity index (CBI) for each year as, CBI = [1- (Y_CB/Y_RP)], where Y_CB and Y_RP are the mean seed yield of all 25 cultivars under the CB and RP systems, respectively. Mean percent reduction (PR) was calculated for each cultivar as PR = [1- (Y_cb/Y_rp)]*100, where Y_cb and Y_rp are the mean seed yield of each cultivar under the CB and RP systems, respectively. Continual dry bean production susceptibility index (CSI) for each cultivar was calculated as, CSI = PR/(CBI*100). All data were analyzed using the SAS (v 9.1) PROC GLM statistical package (SAS Institute, 2004).

	RESULTS AND DISCUSSION

TOP ABSTRACT INTRODUCTION MATERIALS AND METHODS RESULTS AND DISCUSSION REFERENCES

 
Mean squares associated with the cultivar and cultivar x year interaction effects were significant (P < 0.01) for seed yield, seed weight, and days to maturity in both production systems (Table 1 ). Interactions that were different in magnitude as well as different in rank orders among the years and cultivars occurred in either production system. For example, great northern US 1140 had a lower yield than UI 465 in RP system in 1999, however, the opposite occurred in 2000 and 2001 (Table 2 ). Similarly, pinto Frontier tended to have consistently equal or higher yield than Burke in the RP system each year, whereas in the CB system Burke yielded higher than Frontier. However, the year effect was significant in both production systems only for seed yield. Mean square for the year effect for seed weight was significant only in CB and for days to maturity only in RP.

As noted earlier, the CB production for 2 or more years consecutively is common in many regions of the world including North America. However, it is very unlikely that growers would continue to plant dry bean in the same field when the CBI reach significantly high values, that is, 0.50 or greater, that result in corresponding seed yield losses of 50% or more. Thus, to minimize yield losses in short-term CB production systems, yearly or alternate year deep plowing may be advisable provided it does not enhance soil erosion and does not have adverse effects on other soil properties conducive to favorable dry bean production. Conversely, the negative effects associated with CB production may be accentuated in "no-till" and "minimum-tillage" production systems.

Although considerable differences were found within each market class of dry bean cultivars, pinto and great northern market classes had an average of 71% seed yield reduction due to CB production (Table 2). Mean reduction in seed yield of red cultivars was 66%. The pink cultivars, in general, were least affected (56% average yield reduction) by CB production. The mean seed yield of red cultivars was also significantly higher than that of great northern and pinto in RP, but the differences in their mean seed yields were not significant (P > 0.05) in the CB production system. It is worth noting that dry bean cultivars such as Burke (Hang et al., 1998), Harold (Burke et al., 1995), NW 63 (Burke, 1982b), and Viva (Burke, 1982a) developed by the USDA-ARS researchers at Prosser, WA, in general exhibited moderate to high levels of resistance to drought (Miller and Burke, 1983; Muñoz-Perea et al., 2006, 2007; Singh et al., 2001b), low soil fertility (Westermann and Singh, 2000), and Fusarium root rot (Burke and Miller, 1983). This superior performance is largely attributed to use of a "purgatory-plot" system at Roza, WA which is characterized by a heavy infestation of Fusarium root rot, moderate drought and soil fertility stresses, and deliberate establishment of pre-plant soil compaction with alternate-year dry bean production (Miller and Burke, 1983; P. Miklas, unpublished data, 2006) that has been used for germplasm screening and selection for decades. It is therefore not surprising that the USDA-ARS-Prosser cultivars and cultivars such as UI 239 (Myers et al., 1997) and UI 537 (Myers et al., 1993) that were developed at Kimberly, ID but tested at Roza before their release also exhibited the highest levels of resistance to the CB production system. It is also worth mentioning that there has been an excellent collaboration and exchange of germplasm between the USDA-ARS and University of Idaho researchers. Breeding lines from the latter program have been routinely screened in USDA-ARS plots before release. It is thus inferred that the CB production induces a general stress for moisture and nutrient availability and dry bean cultivars resistant to drought and low soil fertility may perform well in the CB production systems. On the other hand, cultivars such as UI 59 (Dean, 2000) and Weihing (Coyne et al., 2000) great northern, Frontier (Grafton et al., 1999) and Kodiak (Kelly et al., 1999a) pinto, and UI 3 (Dean, 2000) red that were among the most susceptible to the CB production system may also be generally susceptible to drought (Muñoz-Perea et al., 2006, 2007; Singh et al., 2001b).

When the mean seed yield over the 3 yr in the CB production system was plotted against the mean seed yield in the RP system, the 25 dry bean cultivars could be classified into four groups (Fig. 1 ). Cultivars in the top-right quadrant comprising UI 537, UI 239, Viva, and Harold had high seed yield in both production systems. In contrast, Frontier, Matterhorn (Kelly et al., 1999b), and others in the top-left quadrant yielded well in the RP system but, on average, these had low seed yield in the CB production system. Similarly, those in the lower-left quadrant performed poorly in both production systems. The actual causes for these differences would be worth investigating. Also, the relationship between yield stability of dry bean cultivars, plant and seed uptake and concentration of nutrients, water uptake and water use efficiency, and their significance to breeding high-yielding dry bean cultivars for the CB production system needs to be determined.

View larger version (9K): [in this window] [in a new window]   Fig. 1. Classification of 25 dry bean cultivars according to the mean seed yield in the continual dry bean and rotational production systems evaluated at the University of Idaho, Kimberly, ID from 1999 to 2001.

As noted earlier, the CB production system also reduced seed weight by an average of 11% (Table 2). Thus, dry bean growers and processors interested in maximizing the recovery percentage (i.e., percentage of good quality marketable seed in the harvested lot) should preferably avoid growing dry bean in the CB production system. Alternatively, cultivation of high-yielding cultivars resistant to CB production with minimum reduction in seed weight such as UI 537 pink should be preferred. In addition, to minimize yield losses, yearly or alternate-year deep plowing may be advisable to facilitate root penetration and water infiltration deeper in the soil horizon.

	ACKNOWLEDGMENTS

 
We thank Marie Dennis for assistance with plot management and Henry Terán and Margarita Lema for data analysis and preparation of summary tables and figure. We also thank Mark Brick, Gary Lehrsch, and Bahman Shafii for statistical advice.

	REFERENCES

TOP ABSTRACT INTRODUCTION MATERIALS AND METHODS RESULTS AND DISCUSSION REFERENCES

 

• Burke, D.W. 1982a. Registration of pink beans Viva, Roza, and Gloria. Crop Sci. 22:684.[Free Full Text]
• Burke, D.W. 1982b. Registration of red Mexican beans Rufus, NW-59, and NW-63. Crop Sci. 22:685–686.[Free Full Text]
• Burke, D.W., and D.E. Miller. 1983. Control of Fusarium root rot with resistant beans and cultural management. Plant Dis. 67:1312–1317.
• Burke, D.W., M.J. Silbernagel, J.M. Kraft, and H.H. Koehler. 1995. Registration of Harold pink bean. Crop Sci. 35:943.[Free Full Text]
• Coyne, D.P., D.S. Nuland, D.T. Lindgren, J.R. Steadman, D.W. Smith, J. Gonzales, J. Schild, J. Reiser, L. Sutton, C. Carlson, J.R. Stavely, and P.N. Miklas. 2000. Weihing great northern disease resistant dry bean. HortScience 35:310–312.[Free Full Text]
• Dean, L.L. 2000. History of bean research and development. p. 3–11. In S.P. Singh (ed.) Common Bean Research, Production, and Utilization. Proc. of the Idaho Bean Workshop, Twin Falls. 3–4 Aug. 2000. Univ. of Idaho, Moscow.
• Fischer, R.A., and R. Maurer. 1978. Drought resistance in spring wheat cultivars. I. Grain yield responses. Aust. J. Agric. Res. 29:897–912.[CrossRef][Web of Science]
• Gentry, H.S. 1969. Origin of the common bean, Phaseolus vulgaris. Econ. Bot. 23:55–69.[Web of Science]
• Grafton, K.F., J.R. Venette, and K.C. Chang. 1999. Registration of ‘Frontier’ pinto bean. Crop Sci. 39:876–877.[Free Full Text]
• Hang, A., M.J. Silbernagel, P.N. Miklas, and G.L. Hosfield. 1998. Registration of Burke pinto bean. Crop Sci. 38:885.[Free Full Text]
• Kaplan, L. 1956. The cultivated beans of the prehistoric southwest. Ann. Mo. Bot. Gard. 43:189–251.
• Kaplan, L., and T.F. Lynch. 1999. Phaseolus (Fabaceae) in archaeology: AMS radiocarbon dates and their significance for pre-Colombian agriculture. Econ. Bot. 53:261–272.[Web of Science]
• Kelly, J.D., G.L. Hosfield, G.V. Varner, M.A. Uebersax, and J. Taylor. 1999a. Registration of ‘Kodiak’ pinto bean. Crop Sci. 39:292–293.[Free Full Text]
• Kelly, J.D., G.L. Hosfield, G.V. Varner, M.A. Uebersax, and J. Taylor. 1999b. Registration of ‘Matterhorn’ great northern bean. Crop Sci. 39:588–589.[Free Full Text]
• McIntosh, M.S. 1983. Analysis of combined experiments. Agron. J. 75:153–155.[Abstract/Free Full Text]
• Miller, D.E., and D.W. Burke. 1983. Response of dry beans to daily deficit sprinkler irrigation. Agron. J. 75:775–778.[Abstract/Free Full Text]
• Muñoz-Perea, C.G., R. Allen, D.T. Westermann, J.L. Wright, and S.P. Singh. 2007. Water use efficiency among dry bean landraces and cultivars in drought-stressed and non-stressed environments. Euphytica 155:393–402.[Web of Science]
• Muñoz-Perea, C.G., H. Terán, R.G. Allen, J.L. Wright, D.T. Westermann, and S.P. Singh. 2006. Selection for drought resistance in dry bean landraces and cultivars. Crop Sci. 46:2111–2120.[Abstract/Free Full Text]
• Myers, J.R., K.D. Stewart-Williams, R.E. Hayes, M.W. Lancaster, and J.J. Kolar. 1997. Registration of ‘UI 239’ small red bean. Crop Sci. 37:287–288.[Free Full Text]
• Myers, J.R., K.D. Stewart-Williams, J.J. Kolar, and R.E. Hayes. 1993. Registration of ‘UI 537’ pink bean. Crop Sci. 33:205.[Free Full Text]
• SAS Institute. 2004. SAS user's guide: Statistics. Cary, NC.
• Singh, S.P. 1982. A key for identification of different growth habits of Phaseolus vulgaris L. Annu. Rep. Bean Improv. Coop. 25:92–95.
• Singh, S.P. 1989. Patterns of variation in cultivated common bean (Phaseolus vulgaris, Fabaceae). Econ. Bot. 43:39–57.[Web of Science]
• Singh, S.P. 1992. Common bean improvement in the tropics. Plant Breed. Rev. 10:199–269.
• Singh, S.P., P. Gepts, and D.G. Debouck. 1991. Races of common bean (Phaseolus vulgaris, Fabaceae). Econ. Bot. 45:379–396.[Web of Science]
• Singh, S.P., R. Hayes, M. Dennis, and E. Powers. 2001a. Effects of 50 years of continual bean cropping on yield and other characters of dry bean cultivars. Ann. Rep. Bean Improv. Coop. 44:77–78.
• Singh, S.P., R. Hayes, C. Robison, M. Dennis, and E. Powers. 2001b. Response of bean (Phaseolus vulgaris L.) cultivars to drought stress. Annu. Rep. Bean Improv. Coop. 44:45–46.
• Terán, H., and S.P. Singh. 2002. Comparison of sources and lines selected for drought resistance in common bean. Crop Sci. 42:64–70.[Abstract/Free Full Text]
• Wallace, D.H. 1985. Physiological genetics of plant maturity, adaptation and yield. Plant Breed. Rev. 3:21–167.[Medline]
• Westermann, D., and S.P. Singh. 2000. Patterns of response to zinc deficiency in dry bean of different market classes. Annu. Rep. Bean Improv. Coop. 43:5–6.
• Woolley, J.R. Lépiz I., T. De A. Portes Castro, and J. Voss. 1991. Bean cropping systems in the tropics and subtropics and their determinants. p. 679–706. In A. van Schoonhoven and O. Voysest (ed.) Common beans: Research for crop improvement. CAB Int., Wallingford, UK and CIAT, Cali, Colombia.

This article has been cited by other articles:

				S. P. Singh, H. Teran, C. G. Munoz-Perea, M. Lema, M. Dennis, R. Hayes, R. Parrott, K. Mulberry, D. Fullmer, and J. Smith Dry Bean Landrace and Cultivar Performance in Stressed and Nonstressed Organic and Conventional Production Systems Crop Sci., August 7, 2009; 49(5): 1859 - 1866. [Abstract] [Full Text] [PDF]

				S. P. Singh, H. Teran, M. Lema, M. F. Dennis, R. Hayes, and C. Robinson Breeding for Slow-Darkening, High-Yielding, Broadly Adapted Dry Bean Pinto 'Kimberly' and 'Shoshone' Journal of Plant Registrations, September 1, 2008; 2(3): 180 - 186. [Abstract] [Full Text] [PDF]

This Article Abstract Figures Only Full Text (PDF) Free Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Hayes, R. Articles by Singh, S. P. Search for Related Content PubMed Articles by Hayes, R. Articles by Singh, S. P. Agricola Articles by Hayes, R. Articles by Singh, S. P. Related Collections Other Legumes Crop Rotation Systems Other Cropping Systems