Rainfed Production Systems Research Articles

High yielding spring bread wheat germplasm for global irrigated and rainfed production systems

Global wheat (Triticum aestivum L.) production must increase 2% annually until 2020 to meet future demands. Breeding wheat cultivars with increased grain yield potential, enhanced water-use efficiency, heat tolerance, end-use quality, and durable resistance to important diseases and pests can contribute to meet at least half of the desired production increases. The remaining half must come through better agronomic and soil management practices and incentive policies. Analyses of the recent International Yield Trials indicate that grain yields of the best new entries were usually 10% higher than the local checks globally, as well as within a country across sites. Variation in yield across sites within a country/region underline the role of genotype × environment (GE) interaction and provides opportunities to select for stable genotypes, which is not often done. The lack of proper analysis undermines proper utilization of germplasm with high yield potential and stability in the national wheat breeding programs. Some of the best performers in irrigated areas were amongst the best in semiarid environments, reinforcing the fact that high yield potential and drought tolerance can be improved simultaneously. The best performing lines often had genotypic base of widely adapted genotypes Kauz, Attila, Baviacora, and Pastor, with genetic contributions from other parents including synthetic wheat. We recommend within country multilocation analysis of trial performance for a crop season to identify lines suiting particular or different locations within a country. The immediate feedback on GE interaction will also help in breeding lines for countries having substantial variation across locations and years.

Categorisation of soils based on potassium reserves and production systems: implications in K management

Crop fertilisation with potassium in rainfed agriculture in India is not practised, merely on the assumption that Indian soils are rich in potassium and crops do not need external K supply. However, under continuous cropping in rainfed regions, huge crop K removals are reported, up to 150–200 kg/ha annually, depending upon amount and distribution of rainfall and biomass production. Thus, most of the crops essentially deplete soil K reserves. The present study evaluates the soil K reserves under diverse rainfed production systems and categorises rainfed soils based on different soil K fractions. Depth-wise sampling was done from 21 locations across different soil types under 8 production systems, and various fractions of soil K were determined. Total K was highest in Inceptisols (1.60–2.28%), followed by Aridisols (1.45–1.84%), Vertisols and Vertic sub-groups (0.24–1.72%), and Alfisols and Oxisols (0.30–1.86%), showing a wide variation within each group. Nonexchangeable K reserves were found in a proportionate manner to total K in most of the soil profile. Unlike nonexchangeable K reserves, Vertisols had higher exchangeable K than Inceptisols and Alfisols/Oxisols. Nonexchageable K showed significant positive correlation with total K in Inceptisols and Vertisols, whereas it was non-significant in Alfisols/Oxisosls. However, significant positive correlations were recorded with exchangeable K and nonexchangeable K in all soil types, indicating the dynamic equilibrium between 2 soil K fractions. Nonexchangeable K reserves were included along with exchangeable K in categorising soils into 9 groups for evolving better strategies to manage soil K fertility in rainfed agriculture in India. Finger millet and groundnut crops at Bangalore and Anantapur regions (category I) need immediate attention on K nutrition, as these soils are low in both exchangeable and nonexchangeable K. Similarly, crops grown on soils of S.K. Nagar, Ballowal-Saunkri, and Rakh-Dhiansar, with low exchangeable K and medium nonexchangeable K, would need K fertilisation as these crops (maize and pearlmillet) are K-exhaustive (category II). Pearl millet and upland rice in category III and cotton in category IV need K additions at critical stages. Upland rice in category V needs a maintenance dose of K. In category VI, cereal crops may not need K additions immediately as they have medium exchangeable K and high nonexchangeable K. Long-term sorghum cropping may need K supply after few years (category VII). Soils in category VIII are adequate in nonexchangeable K and medium exchangeable K and the crops, groundnut, cotton, sorghum, and soybean, may not need external K immediately. For soils in category IX, K fertilisation is not required to the crops (sorghum and soybean) as these soils have high exchangeable and nonexchangeable K.

Forecasting Yield Behavior of Potato, Mustard, Rice, and Wheat Under Irrigation

Current agriculture development policy focuses on maximizing harvest without sacrificing the economics of crop production by judicious utilization of natural and human resources. Irrigated production systems are favored because of attributes not provided in rain-fed production systems. In India planners must determine how to supply food for its citizens. This study examined, using records from 1971 to 2001, changes in yield, area under cultivation, and production efficiency, of the dry season crops: rice (Oryza sativa L.), wheat (Triticum aestivum L.), potato (Solanum tuberosum L.), and mustard (Brassica juncea L.), which in the future may compete in time and space. Forecasting was made with respect to yield of each crop, area under cultivation, and production efficiency. Different Auto Regressive (AR) and Auto Regressive Integrated Moving Average (ARIMA) models explained yield trends. The study revealed that there existed a gap between the achieved average production efficiency and the potential production efficiency of each crop. Results indicated that production efficiency of rice declined, but production efficiency of potato, wheat, and mustard improved up to 2001. Forecasting yield trends indicated that potato has the potential to supply food requirements in the near future and mustard can be used as short duration crop within the existing cropping sequences. It appears that potato has a better return per unit of input use, and should be considered for inclusion in the cropping system instead of rice, which requires more water and has declining production efficiency.

QTL analysis of genotype x environment interactions affecting cotton fiber quality.

Cotton is unusual among major crops in that large acreages are grown under both irrigated and rainfed conditions, making genotype x environment interactions of even greater importance than usual in designing crop-improvement strategies. We describe the impact of well-watered versus water-limited growth conditions on the genetic control of fiber quality, a complex suite of traits that collectively determine the utility of cotton. Fiber length, length uniformity, elongation, strength, fineness, and color (yellowness) were influenced by 6, 7, 9, 21, 25 and 11 QTLs (respectively) that could be detected in one or more treatments. The genetic control of cotton fiber quality was markedly affected both by general differences between growing seasons ("years") and by specific differences in water management regimes. Seventeen QTLs were detected only in the water-limited treatment while only two were specific to the well-watered treatment, suggesting that improvement of fiber quality under water stress may be even more complicated than improvement of this already complex trait under well-watered conditions. In crops such as cotton with widespread use of both irrigated and rainfed production systems, the need to manipulate larger numbers of genes to confer adequate quality under both sets of conditions will reduce the expected rate of genetic gain. These difficulties may be partly ameliorated by efficiencies gained through identification and use of diagnostic DNA markers, including those identified herein.

El Niño-Southern Oscillation effects on peanut yield and nitrogen leaching

Peanut growers in north Florida asked for help in managing the crop to increase yield and reduce yield variability, using information on the pattern of large-scale climate. The objectives of this study were to explore at 4 locations in the peanut belt of Florida and southern Georgia the potential for improving peanut crop performance by altering crop management according to the phase of the El Nino-Southern Oscillation (ENSO). The CROPGRO-Peanut model was used to simulate peanut yield responses to climate and management. The effects of planting date and irrigation management options on the mean and variability of simulated crop yield and nitrogen leaching in different ENSO phases were estimated. This case study showed potential for enhancing peanut yields (1 to 8%) and reducing yield variability (2 to 12%) by tailoring planting dates to expected ENSO conditions, while at the same time reducing potential environmental damages from nitrogen leaching by 1 to 11%. Locations which appeared to have no ENSO linkages currently showed most responses to tailored management in this simulation study. Tailored management calls for later planting during an El Nino, and earlier planting in a La Nina. When planting dates were tailored to ENSO phases, simulations showed at least 10% lower nitrogen leaching from rainfed production systems in about 70% of the years. Among ENSO phases, La Nina seasons were shown to have greater nitrogen leaching, with little response to management changes relative to El Nino seasons. Tailored management may be most advantageous in El Nino seasons as a result of higher yields and lower nitrogen leaching. Further research is needed before options derived from simulations and optimization can be recommended and adopted with confidence by growers and extension advisors.

Risk Assessment of Herbicide-Resistant Crops: A Latin American Perspective Using Rice (Oryza sativa) as a Model1

Herbicide-resistant crops (HRCs), particularly glyphosate-resistant soybean, are increasingly important in Latin America. Prior to commercial release of these crops, their short- and long-term risks should be thoroughly assessed. A risk assessment should include the identification and characterization of potential hazards and an estimation of the likelihood of these hazards occurring. For HRCs the agro-ecological hazards are mostly related to the occurrence of herbicide-resistant (HR) weeds and crop volunteers and the adverse effects from the use of pesticides within the agricultural area. Herbicide-resistant rice is used as a case study to visualize the key components of such a risk assessment. For this purpose, a model that simulates a typical rain-fed rice production system in Central America was developed. The model was used to investigate the selection of HR weedy rice populations under various scenarios. Scenarios included contrasting weed management practices, hybridization levels between the comme...

Rainwater management for increased productivity among small-holder farmers in drought prone environments

A critical analysis of conventional water resources assessments and re-visiting the on-farm water balance suggests large scopes for water productivity improvements in small-holder rainfed farming systems in drought prone environments of Eastern and Southern Africa. The paper addresses key management challenges in trying to upgrade rainfed agriculture, and presents a set of field experiences on system options for increased water productivity in small-holder farming. Implications for watershed management are discussed, and the links between water productivity for food and securing of water flow to sustain ecosystem services are briefly analysed. Focus is on sub-Saharan Africa hosting the largest food deficit and water scarcity challenges.The paper shows that there are no agro-hydrological limitations to doubling on-farm staple food yields even in drought prone environments, by producing more “crop per drop” of rain. Field evidence is presented suggesting that meteorological dry spells are an important cause for low yield levels and it is hypothesised that this may constitute a core driver behind farmers risk aversion strategies. The dry spell induced risk perceptions contribute amongst others to soil nutrient mining due to insignificant investments in fertilisation. For many small-holder farmers in the semi-arid tropics it is simply not worth investing in fertilisation (and other external inputs) as long as the risk for crop failure remains a reality every fifth year with risk of yield reductions every second year, due to periodic water scarcity during the growing season (i.e., not necessarily cumulative water scarcity).Results are presented from field research on small-holder system innovations in the field of water harvesting and conservation tillage. Upgrading rainfed production systems through supplemental irrigation during short dry-spells is shown to dramatically increase water productivity. Downstream implications of increased upstream withdrawals of water for upgrading of rainfed food production are discussed.Finally it is argued that some of the most exciting opportunities for water productivity enhancements in rainfed agriculture are found in the realm of integrating components of irrigation management within the context of rainfed farming, e.g., supplemental or micro irrigation for dry spell mitigation. Combining such practices with management strategies that enhance soil infiltration, improve water holding capacity and plant water uptake potential, can have strong impact on agricultural water productivity. This suggests that it is probably time to abandon the largely obsolete distinction between irrigated and rainfed agriculture, and instead focus on integrated rainwater management.

Smallholder farming systems in Asia

Agricultural production in Asia emphasises intensive rice and wheat production. Other systems are associated with maize, cassava, trees and a range of secondary crops. Both monoculture and multiple cropping systems are common, with crops being grown for subsistence and cash. Irrigated agriculture is well developed in high potential areas, but most countries are still heavily dependent on rain-fed production systems. In Southeast Asia, shifting cultivation is practised widely and is associated with deforestation, weed invasion and erosion. Multi-purpose livestock are integrated with cropping in small-scale, mixed farming systems that characterise Asian agriculture.

Crop–animal systems in Asia: implications for research

The importance of crop–animal systems in Asia, the multiple roles played by animals and the opportunities for increasing their contribution to these systems justifies continued research effort. An assessment of the role of livestock in mixed farming systems in 14 countries has identified priority systems, technical constraints and weaknesses in the national organisations. Future research needs to focus on the rain-fed production systems, where most of the livestock are found. There is an overriding need for a farming systems perspective to the research agendas that involves inter-disciplinarity and community-based participation. Such an approach will be more complex, require concentrated effort and more efficient resource use, but will be associated with considerable benefits due to a greater integration of effort.

Crop–animal systems in Asia: importance of livestock and characterisation of agro-ecological zones

Crop–animal systems, in which livestock play a multi-purpose role, are the backbone of Asian agriculture. In the future, increased productivity from livestock will be necessary in these systems to meet the increased demand for animal products, to alleviate poverty and to improve the livelihoods of resource-poor farmers. Agriculture in the region is characterised by diverse and complex production systems, which reflect the wide range of physical environments. In Southeast Asia, the main agro-ecological zones are characterised by humid/sub-humid climates, whilst those in South Asia are arid/semi-arid. Irrigated agriculture is well developed in high potential areas but, with the exception of Pakistan, the countries still depend heavily on rain-fed production systems. Most soils are of low fertility and some, such as the vertisols, present management problems. The natural vegetation consists of forests and native grasslands, with the latter more common in South Asia. Land degradation is a major concern and threatens the sustainability of the farming systems.

Identification of suitable cultivars for organically grown maize (Zea mays) French bean (Phaseolus vulgaris L.) cropping system of Eastern Himalayas

An experiment was conducted at Umiam, Meghalaya, to assess the performance of different cultivars of maize (Zea mays L.) followed by no-till French bean (Phaseolus vulgaris L.) in cropping system mode under organic pro- duction system. During 2015, 2016 and 2017. The experiment was conducted with 10 cultivars of maize (8 com- posite cultivars and 2 local lines) followed by 10 cultivars of French bean (8 improved cultivars and 2 local variet- ies). Among all the maize cultivars evaluated over the years, maximum and minimum values of cob length, cob weight, green cob yield and kernel yield were noticed in variety RCM 1-61 and Local white respectively. Signifi- cantly higher chlorophyll index at 60 days after sowing (DAS) was recorded in RCM 1-61 followed by RCM 1-3 and minimum in RCM 1-1 followed by Hemant. Moreover, RCM 1-3 and RCM 1-2 varieties of maize recorded significantly higher crude protein content, whereas RCM 1-3 followed by Local Yellow recorded higher crude fi- bre against the other varieties of maize. The average highest yield of French bean in terms of green pod was re- corded in Naga local (8.91 t/ha) followed by RCM FB 18 (7.93 t/ha), RCM FB 19 (5.74 t/ha) and RCM FB 80 (5.73 t/ha). The maximum maize-equivalent yield (17.1 t/ha) and system productivity (6.3 t/ha) was observed for RCM 1-61 (maize cultivar)Naga local (French bean) followed by RCM 75 (maize)RCM FB 18 (French bean) sequence. The highest net returns (`2,24,059/ha) also recorded from the RCM 1-61 (maize cultivar)Naga local (French bean) cropping sequence. The soil organic carbon concentration was also enhanced after 3 years owing to adoption of maizeFrench bean cropping sequence and the highest value (21.8 g/kg) was recorded in RCM 1- 61 (maize cultivar)Naga local (French bean) sequence. The present study reveals the scope of successful culti- vation of French bean in no-till maize fallow under organic rainfed production system.

Economic Sustainability of Dry Land Use: The Case Study of Irsal, Lebanon

ABSTRACT Sustainable agriculture is the development of technology and practices that maintain the production of a safe nutritious food that is sustainable at a long term both economically and physically. In Lebanon, sustainable agriculture is still a new approach due to the impact of the civil war on this sector leading to the degradation of natural resources. The main objective of this paper is to study the economic sustainability of a transition from a traditional agropastural system to a rainfed fruit production system in the dry land of Irsal, northeast of Lebanon. Economic and financial analyses for livestock and cherry productions were conducted under different operational scale (small, medium, and large) to estimate systems profitability, and thus justify the economic motivation for such changes. The cherry crop was used in this study since it is the most dominant crop in the current changes that are taking place. The results indicate that, the transition from the agropastoral system to fruit production is justifiable given the economic motivations and the increase in the returns due to such changes. Fruit tree production is more profitable and less demanding for time and labor as compared to the old system. However, the continuous existence of the ruminant flocks is due to the fact that they represent a cash stock that can be liquidated in times of need.

Gas Exchange Characteristics of the Flue-Cured Tobacco (Nicotiana Tabacum L.) Cultivars Grown under Two Production Systems

The net photosynthetic rate (PN), intercellular CO2 concentration (Ci), stomatal conductance (gs), transpiration rate (E), water use efficiency (WUE), and leaf biomass production of four American flue-cured tobacco (Nicotiana tabacum L.) cultivars K 326, K 358, and Speight G 28 were compared with three local Indian cultivars 16/103, Special FCV, and PCT-7, during 1994 and 1995 crop seasons under irrigated and rainfed production systems (Northern light soils, NLS, and Karnataka light soils, KLS) in India. By comparison, the American tobacco cv. K 326 showed the highest PN and gs. A positive correlation was found between PN and biomass production in all the varieties tested (r = 0.55 in NLS and 0.73 in KLS). The American cultivars were superior than the local cultivars in their biomass production and PN under Indian farming conditions.

Effect of conservation tillage on crop yields, soil erosion, and soil properties under furrow irrigation in western Colorado

AbstractConservation tillage (CS) is used widely in rainfed and sprinkler-irrigated production systems but adoption of CS on furrow-irrigated cropland has been limited. Some crops and crop rotations are more conducive to conservation tillage under furrow irrigation than others. The objective of this research was to evaluate CS in a furrowirrigated crop rotation of corn, soybean, winter barley, and dry bean at Fruita, Colorado in 1991 and 1992. Infiltration rates were 24 and 50% higher and advance times were 37 and 25% longer in the CS treatment during 1991 and 1992, respectively, compared with conventional tillage (CV). Furrows in the CV treatment were 8 and 25% wider than those in the CS treatment after the first and sixth irrigations, respectively. This indicates more soil movement with CV than with CS. In 1992, soil water content in the CS treatment was 17, 17, and 27% higher than with CV throughout the growing season for corn, soybean, and dry bean, respectively. Grain yields of winter barley, soybean, dry bean, and corn were not affected significantly by tillage treatment. Profitability of CS and CV was quite similar when all four crops in the rotation were considered together. This research was conducted under conditions expected to be similar to those that could be used by growers and indicates that corn, soybean, winter barley, and dry bean can be grown successfully in rotation using conservation tillage under furrowirrigated conditions. Successful adoption of conservation tillage under furrow irrigation will require growers to adopt encompassing new production management practices and possibly purchase new equipment such as planters and cultivators that will operate in high residue conditions, and growers must overcome any psychological barriers they may have to maintaining high amounts of surface crop residue when furrow irrigating.

U 234/U 238 ratios in coastal marine waters and calcium carbonates : Blanchard Richard L., 1965. J. geophys. Res., 70 (16): 4055–4061.

U 234/U 238 ratios in coastal marine waters and calcium carbonates : Blanchard Richard L., 1965. J. geophys. Res., 70 (16): 4055–4061.