Rainfed Locations Research Articles

Aquifer connectivity assessment using stable isotope and hydrochemical analysis in the Raimanuk and its surrounding area on the Timor island

Raimanuk and its surroundings are a potential agricultural area in Indonesia. Sufficient groundwater in this area was a significant factor for supporting agricultural activities and household needs. Therefore, identifying the aquifer connectivity is essential to determine the groundwater utilization pattern in this area. This research aims to determine the aquifer connectivity based on stable isotopes and hydrochemical from the groundwater and the meteoric water (rainwater). The groundwater samples were taken from ten deep wells, six dug wells, and four springs. While the meteoric water samples were taken from four rainfed locations, samples were analyzed using Los Gatos Research DLT-100, Ion Chromatography Metrohm 830IC, and acid-base titration. The result shows there are four groups of groundwater. Group I is the springs that come from local meteoric water. Group II consists of the dug wells that evaporated and showed a relationship to the meteoric water that falls in higher elevations. Group III was the drilled well groundwater from the local flow system. Furthermore, Group IV is the drilled well groundwater with a more enriched δ18O isotope ratio due to water-rock interaction. Even though they are in a different group, there is a hydraulic connection between Group III and IV.

Estimating the economic value of green water as an approach to foster the virtual green-water trade

Green water – precipitation that is stored in the soil as moisture and consumed in the production of biomass – provides the main source of water for crop cultivation, pasturelands, forestry, and terrestrial ecosystems. At a local level, green water is land-bound and cannot be easily allocated between uses. However, at the global level, agricultural commodities and their embodied virtual water are traded between countries. This trade typically sees the cultivation of crops in water abundant rainfed locations exported to regions that would otherwise have employed local irrigation resources. The result is a global saving of irrigation water and the negative environmental externalities associated with irrigation. In addition, scarce blue water resources are freed up for other (often higher valued) uses.Here we assess whether there is an economic rationale for the virtual green-water trade and the increased and intentional allocation of crop cultivation to water abundant rainfed locations. We model a realistic case study of maize cultivation on representative farms in 16 major maize producing regions (across four continents) and provide the first spatially variable estimates of the economic value of the green water employed. These economic values are contrasted with the economic value of blue water used for irrigation. We find that the volume of green water employed in the cultivation of maize varies between 409 m3/tonne and 1547 m3/tonne; the estimated economic value of green water varies between $ −0.04 m3 and $0.12 m3. We demonstrate how these economic value estimates can inform crop allocation decisions in favour of green water-based cultivation and inform decisions regarding the intensification and horizontal expansion of rainfed agriculture. In so doing, we aim to provide a further rationale for the green water-based measures that have been identified in the literature as the principal means of providing the additional fresh water needed to address pressing global challenges beyond the case study.

New Rainfed-Drought Rice Variety developed through In Vitro Mutagenesis

In vitro mutagenesis (IVM), a technique combining tissue culture and gamma irradiation (30 Gy 60Co), was performed with a modern upland rice variety NSIC 2001 Rc 9 (NSIC Rc9), locally known as Apo. The breeding strategy was implemented to improve the variety’s grain quality, specifically its grain size and shape, and amylose content. The induced mutation strategy regenerated 55 IVM1 families from which the IVM2 population was generated comprising of 206 segregating plants. Phenotypic variability assessment conducted in 2009 wet season resulted in the selection of 150 plants with acceptable phenotypes. After a series of evaluations and selection for grain quality, drought stress tolerance and grain yield, seven elite lines were selected for multi-environment trial (MET) in four rainfed locations. The MET identified four lines ready for nomination to the National Cooperative Testing (NCT) for further evaluation and recommendation to the National Seed Industry Council (NSIC) as a new variety for release. In 2015, the line PR41395-NSICRc9-IVM2009DS 50-1-4 (IVM-032) was entered into NCT as one of the breeding lines evaluated under the rainfed-drought prone rice ecosystem. In 2019, the line was released as a new variety recommended for cultivation and consumption. The IVM-032 was officially registered as NSIC 2019 Rc572 and with the variety name of Sahod Ulan 28.

Yield gaps of lucerne (Medicago sativa L.) in livestock systems of Argentina

AbstractArgentina grows the second‐largest area of lucerne in the world. Despite its importance, a yield gap exists between potential and measured yields, but factors contributing to it are still unclear. This study aimed to identify management factors and research needs to reduce the lucerne yield gap to improve the livestock systems in this region. We used meteorological data coupled with lucerne crop modelling and measured yields from the National Lucerne Cultivar Evaluation Network (NLCEN) to quantify the lucerne yield gap in nine sites located within the Argentinian Pampas (between parallels 30–45°S and meridians 58–65°W) and three sites outside the Pampas. Specifically, we used the model developed by McCall & Bishop‐Hurley (2003), adapted and calibrated for lucerne in Argentina by Berone et al. (2017) to estimate the potential yield (PY) for 12 locations (three irrigated and nine rainfed), and compared those results with measured yields from the NLCEN to calculate yield gaps. We found the average available photosynthetic active radiation (PAR) and temperatures were sufficient to achieve 21.5 ± 3.7 t dry matter (DM) ha−1 yr−1 under rainfed conditions (environments with mean annual rainfall from 400 to 1,200 mm). However, the average measured yield from the NLCEN was 16.8 ± 2.4 t DM ha−1 yr−1 (a 22% gap). Potential yields ranged between 10 and 25 t DM ha−1 yr−1 under rainfed conditions and between 25 and 39 t DM ha−1 yr−1 for irrigated crops. As latitude increased rainfed locations had lower yields, while irrigated locations had higher yields. Adding irrigation was predicted to increase yields to 35.4 ± 2.0 t DM ha−1 yr−1 (a 53% gap) in rainfed sites. For irrigated locations, the gap was smaller (27.3 ± 3.5 vs 32.4 ± 2.2 t DM ha−1 yr−1 for measured vs potential yield, respectively), and most likely linked to nutrient deficits. Also, current grazing management was estimated to achieve approximately 50% less grazing efficiency than optimal grazing management. Our results demonstrated that the livestock industry can potentially increase animal production under current environmental conditions. The four main adjustments to achieve this are increased use of irrigation, increased use of fertilisers, earlier commencement of grazing in spring and increased stocking rates. The costs of irrigation, fertilisers and grazing management are envisaged to be small compared with potential increases in incomes and thus profitability available to beef and dairy farmers using lucerne as a major feed source in Argentina.

CONCEPT AND RATIONALE OF EVOLUTIONARY BARLEY BREEDING UNDER CLIMATE CHANGE IN JORDAN

In this study, we reviewed the climate changing and the impact on crop production, and evolutionary breeding as adaptation key to crop resilience. The increasing climate change impact on the agriculture system has renewed interest to the broadest possible germplasm base for a resilient and sustainable food system. Heterogeneous populations developed through evolutionary plant breeding could be the ideal solution to reduce the effects of environment variability on cereal crop planted under low-input conditions.The study assessed the genetic basis of adaptation of a barley population which evolved in different rainfed locations and years in Jordan without any human selection as suggests model of plant breeding strategy to improve food security, nutrition, income and resilience of smallholder farmers in the dryland regions in the climate change scenarios. The study suggests that the breeder can shift the undesirable traits in evolutionary populations by practicing individual selection for specific adaptations, or individual selection from populations showing wide adaptations and high stability. On the other hand, the breeder can overcome the undesirable traits by keeping the highest variations within the population by seed sieving to remove small seed and plant mowing for tallest head.

Identification of pigeonpea genotypes with wider adaptability to rainfed environments through AMMI and GGE biplot analyses

Pigeonpea [Cajanus cajan (L.) Millspaugh] is an important pulse crop grown under Indian rainfed agriculture. Twenty eight pigeonpea genotypes were tested for stability and adaptability across ten rainfed locations in the States of Telangana and Karnataka, India using AMMI (additive main effects and multiplicative interaction) model and GGE (genotype and genotype by environment) biplot method. The grain yields were significantly affected by environment (56.8%) followed by genotype × environment interaction (27.6%) and genotype (18.6%) variances. Two mega environments were identified with several winning genotypes viz., ICPH 2740 (G15), TS 3R (G10), PRG 176 (G8) and ICPL 96058 (G22). E2 (Gulbarga, Karnataka), E3 (Bidar, Karnataka) and E6 (Vikarabad, Telangana) were the most discriminating environments. Genotypes, ICPH 2740, PRG 176 and TS 3R were the best cultivars in all the environments whereas PRG 158 (G9), ICPL 87119 (G12), ICPL 20098 (G19) and ICPL 96058 (G22) were suitable across a wide range of environments. Genotypes, ICPH 2740 and PRG 176 can be recommended on a large scale to the farmers with small holdings to enhance pigeonpea productivity and improve the food security

Residual effects of nitrogen application and legume crops on the economics of spring wheat and canola

The objective of this article is to summarize the results of a study conducted over six years at seven rainfed locations on the Canadian Prairies to determine the residual effects of preceding legume crops and past N fertilizer application rates on the economics of subsequent spring wheat and canola. Earn 0.5 CEUs in Crop Management by reading this article and taking the quiz at www.certifiedcropadviser.org/education/classroom/classes/552.

Large-Scale Dryland Cropping Systems

A large-scale dryland cropping systems research and demonstration project at the Southwest ResearchExtension Center near Tribune, Kansas, evaluated two summer crops (corn and grain sorghum) along with winter wheat in crop rotations varying in length from 1 to 4 years. The rotations were continuous grain sorghum, wheat-fallow, wheat-corn-fallow, wheat-sorghum-fallow, wheat-corn-sorghum-fallow, and wheatsorghumcorn-fallow. The objective of the study is to identify cropping systems that enhance and stabilize production in rain-fed locations to optimize economic crop production. Averaged across the past 7 years, wheat yields ranged from 22 to 25 bu/a and were not affected by length of rotation. Corn and grain sorghum yields (7-year average) were about twice as great when following wheat than when following corn or grain sorghum. Grain sorghum yields were almost twice as great as those of corn in similar rotations.

Pasture and the theory of diversification

Diversifying farm activities can reduce the business risk of agricultural production. The aim of the present study was to investigate the effect of diversifying the types of dairy pastures sown on (1) the average seasonal growth rate (kg DM/ha/day) of pasture and (2) the variability of seasonal growth rate of pasture over time by diversifying the types of pastures grown on a dairy farm. This approach is similar to the approach used to assess the diversification of annual cropping activities, although repeated harvest of pasture by grazing animals and the seasonality of pasture DM production complicates the question. The question investigated was ‘How does substituting chicory (Cichorium intybus L.) or tall fescue (Festuca arundinaceae Schreb.) monocultures for a perennial ryegrass (Lolium perenne L.)–white clover (Trifolium repens L.) pasture in increasing proportions affect (1) the average growth rate (kg DM/ha.day) of pasture and (2) the variability of growth rate of pasture in each season?’. The biophysical model DairyMod was used to simulate 30 years growth of a mixed sward of perennial ryegrass and white clover and monocultures of chicory and tall fescue for two rain-fed locations in the high-rainfall zone of southern Australia. Including chicory in the pasture base had the potential to increase pasture growth rate during the summer–early autumn period compared with growing perennial ryegrass–white clover alone. This increase in pasture growth rate increased variability, and reduced growth rates in late autumn–winter and spring. The simulated growth rates of tall fescue and perennial ryegrass were strongly correlated in all seasons; hence, tall fescue did not reduce the variability of total DM. Further analysis would include price correlations and variability and consider the whole-farm implications. The analysis presented here for the high-rainfall zone showed that introducing alternative forages may have benefits in terms of increasing pasture growth rates at critical times of the production year, but the variability of the growth rate was not reduced.

Registration of ‘Serenut 5R’ Groundnut

‘Serenut 5R’ (Reg. No. CV‐129, PI 676092) is a new high‐yielding, spanish‐type groundnut (Arachis hypogaea L. subsp. fastigiata var. vulgaris) with two seeds per pod. Serenut 5R was released in 2010 by the National Semi‐Arid Resources Research Institute, Soroti, Uganda. It was a selection from the ICRISAT advanced line ICGV‐SM 93535. Serenut 5R originated from a cross made between ICGM 522 and ‘RG 1’. ICGV‐SM 93535 was developed by using repeated bulk selections for groundnut rosette disease resistance, using the infector row technique at the ICRISAT‐Malawi research station. Performance tests in replicated trials were performed in Uganda in 2008 and 2009. Trials were performed in two seasons each year and averaged over 10 rainfed locations in Uganda. Serenut 5R matures in 100 to 110 d, similar to the widely grown control cultivar Serenut 3R. Serenut 5R resulted in significantly higher pod yields (16%) than Serenut 3R, and the shellout percentage for Serenut 5R was 4.8% higher than Serenut 3R. Seed testa is red, and the seeds are slightly larger than those of Serenut 3R. The sound mature kernel count for Serenut 5R was 38.7 g 100−1 compared with 32.38 g 100−1 for Serenut 3R, an increase of 19.51%. The dormancy period for Serenut 5R was significantly less than Serenut 3R.

Effects of genotype and environment on grain yield and quality traits in bread wheat (T. aestivum L.)

Genotype (G), environment (E) and their interaction (GEI) play an important role in the final expression of grain yield and quality attributes. A multi-environment trial in wheat was conducted to evaluate the magnitude of G, E and GEI effects on grain yield and quality of wheat genotypes under the three rainfed locations (hereafter environment) of Central Anatolian Plateau of Turkey, during the 2012-2013 cropping season. Grain yield (GY) and analyses of test weight (TW), protein content (PC), wet gluten content (WGC), grain hardness (GH), thousand kernel weight (TKW) and Zeleny sedimentation volume (ZSV) were determined. Allelic variations of high and low molecular weight glutenin subunits (HMW-GS and LMW-GS) and 1B/1R translocation were determined in all genotypes evaluated. Both HMW-Glu-1, 17+18, 5+10 and LMW-Glu-3 b, b, b corresponded to genotypes possessing medium to good quality attributes. Large variability was found among most of the quality attributes evaluated; wider ranges of quality traits were observed in the environments than among the genotypes. The importance of the growing environment effects on grain quality was proved, suggesting that breeders' quality objectives should be adapted to the targeted environments.

Transgenic alteration of ethylene biosynthesis increases grain yield in maize under field drought‐stress conditions

A transgenic gene-silencing approach was used to modulate the levels of ethylene biosynthesis in maize (Zea mays L.) and determine its effect on grain yield under drought stress in a comprehensive set of field trials. Commercially relevant transgenic events were created with down-regulated ACC synthases (ACSs), enzymes that catalyse the rate-limiting step in ethylene biosynthesis. These events had ethylene emission levels reduced approximately 50% compared with nontransgenic nulls. Multiple, independent transgenic hybrids and controls were tested in field trials at managed drought-stress and rain-fed locations throughout the US. Analysis of yield data indicated that transgenic events had significantly increased grain yield over the null comparators, with the best event having a 0.58Mg/ha (9.3bushel/acre) increase after a flowering period drought stress. A (genotype×transgene)×environment interaction existed among the events, highlighting the need to better understand the context in which the down-regulation of ACSs functions in maize. Analysis of secondary traits showed that there was a consistent decrease in the anthesis-silking interval and a concomitant increase in kernel number/ear in transgene-positive events versus nulls. Selected events were also field tested under a low-nitrogen treatment, and the best event was found to have a significant 0.44Mg/ha (7.1bushel/acre) yield increase. This set of extensive field evaluations demonstrated that down-regulating the ethylene biosynthetic pathway can improve the grain yield of maize under abiotic stress conditions.

Net Return Risk for Malting Barley Production in Western Canada as Influenced by Production Strategies

The objective of this study was to evaluate the impact of agronomic practices on net return (NR) risk for malting barley (Hordeum vulgare L.) production. This study used data from two field experiments conducted from 2005 to 2008 at eight rainfed locations in western Canada. The first part of this study included 30 production strategies of barley type, seeding rate, and N rate for four regions. The second part of this study included 10 production strategies of seeding date and seeding rate for four regions. A stochastic simulation model was specified to compute the NR. Yield, protein, plumpness, and price were random in the model, drawn from multivariate distributions based on field data and historical price data. The malting cultivar CDC Copeland had higher NR than AC Metcalfe or feed barley. Seeding early at a rate of 200 to 300 seeds m−2 had higher NR than late seeding or higher seeding rates. A fertilizer rate of 60 to 90 kg N ha−1 had higher NR. A producer with high risk aversion preferred strategies that were less risky including: less N fertilizer, growing feed barley in regions that have high protein and smaller price premiums for malting, and seeding later.

Genotype X seed production environment interaction on the performance of sorghum (Sorghum bicolor [L.] Moench) under irrigation

The ecological conditions prevailing during seed development, maturation and harvesting affect the physical and the physiological characters of the seed produced. The interactive of seed source and genotype on the performance of sorghum (Sorghum bicolor {L.} Moench) grown under irrigation was investigated. One-field experiment was conducted for two consecutive seasons (2006/07-2007/08) in the Demonstration Farm of the Faculty of Agriculture at Shambat. The seeds were obtained from four different locations, viz; two rain-fed locations (Damazin and Gedarif) and two irrigated locations (Khashm el Girba and Sinnar). The cultivars used were two improved (Tabat and Wad Ahmed) and two local cultivars (Arfaa Gadamak and Zahrat elgadambalia). The results indicated that, among the measured attributes, seed source had only significant effects on grain yield, number of heads per plant and number of seeds per head. The highest grain yield was obtained from seeds produced under rain-fed locations (2.0 tones/ha) compared to irrigated locations (1.6 tones/ha). The high yield of the rain-fed location was associated with greater number of heads per plant and number of seeds per head. Irrespective of the seed source, the improved cultivars out yielded the local ones in most of the parameters measured. In this respect, the improved cultivars had significantly greater number of grains/head and greater yield compared to the local cultivars. In contrast, the local cultivars were earlier compared to the improved ones. It is apparent, however, that sorghum seeds obtained from diverse environments can be grown provided that suitable cultivars are selected according to the prevailing environmental conditions.

Yield potential and forage quality of annual forage legumes in southern Alberta and northeast Saskatchewan

There is limited information on the adaptability of small and medium-seeded annual legumes in Western Canadian cropping systems. Pea (Pisum spp.), vetch (Vicia, Lathyrus spp.), medic (Medicago spp.), alfalfa (Medicago spp.), berseem clover (Trifolium alexandrinum L.), arrowleaf clover (T. vesiculosum L.), Persian clover (T. resupinatum L.), balansa clover [T. michelianum Savi. var. balansae (Boiss.) Azn.], rose clover (T. hirtum All.), crimson clover (T. incarnatum L.) and black lentil (Lens culinaris Medik.) were grown at Lethbridge and Brooks, Alberta, and at Melfort and Nipawin, Saskatchewan over a 2 or 3 yr period to assess their forage yield potential under irrigation and dryland conditions. Measurements included plant height, stand establishment, flowering date, forage yield and forage quality. Peas, winter and hairy vetch, and berseem clover were the top yielding species across locations (5452–6532 kg ha-1). Berseem clover, hairy vetch, winter vetch, Nitro alfalfa, and Persian clover yielded in excess of 9000 kg ha-1 under irrigation at Brooks. Hairy and winter vetches, Magnus pea, chickling vetch (Lathyrus sativus L.) and berseem clover yielded over 4300 kg ha-1 in dryland and rainfed locations at Lethbridge, Melfort and Nipawin. These entries had an upright growth habit, established quickly and were normally harvested twice. Crude protein concentration and yields were higher in legumes at irrigated locations in Alberta than rainfed locations in central Saskatchewan. Burr medic at the Brooks irrigated location produced the highest crude protein yield of 2495 kg ha-1. Berseem clover, Persian clover, Nitro alfalfa, hairy and winter vetches show promise as legumes in short term rotations, as green manures and intercrops for increasing forage quality in silage or late season grazing in Western Canada. Key words: Medicago, Trifolium, Vicia, Pisum, Lens, forage yield, forage quality

Evaluation of Soil Nitrate as a Predictor of Nitrogen Requirement for Sugar Beet Grown in a Mediterranean Climate

Rational N fertilization is important to reduce environmental impact of fertilization and to increase profitability in crop production. An evaluation of preplant soil nitrate concentration in soil to estimate optimum N rate for autumn‐sown sugar beet (Beta vulgaris L.) was done by performing 33 N response experiments in different locations between 1989 and 2000. For each location and year, the N rate for maximum beet and sucrose production and the economic optimum N rate for adjusted beet production (yield adjusted for sucrose concentration) were estimated. Nitrate N concentration in the soil (0–30 cm deep) before fertilization ranged between 6 and 156 mg kg−1. This concentration allows one to distinguish between N responsive and nonresponsive sites when no particular leaching (tile‐drained soils in rainy winters—more than 470 mm from October to January—or furrow irrigated) or water stress limitations exist (rainfed locations with less than 350 mm annual rainfall—less than 170 mm during spring). A critical value for the preplant soil nitrate was determined, above which no response to N fertilizer can be expected. This value was 39 mg kg−1 for beet production and 33 mg kg−1 for adjusted beet production. Preplant soil nitrate also provided an accurate estimation of the optimum N rate for adjusted beet production under the same conditions (R2 = 0.93). It is concluded that soil nitrate before planting can be a useful method for assessing N fertilizer rate in production of sugar beet under a Mediterranean climate in soils where leaching is not favored by tile draining or where yield potential is not excessively limited by water supply.

Effects of Nitrogen and Sulfur on Canola Yield and Nutrient Uptake

Spring canola (Brassica napus L. var. napus) is becoming a significant oilseed crop adapted to the western USA. Often N and S limit crop growth. Field experiments were established to study the effects of N and S fertilization on seed yield, oil content, and N, P, K, and S uptake of spring canola. Four N rates in combination with three S rates were evaluated on two irrigated and three rainfed locations in the western triangle area of Montana near Conrad. Seed yields ranged from 0.1 to 3.8 Mg ha−1. Seed yield and oil content N responses were closely related to available N (fertilizer N plus soil NO3–N in 90 cm of soil). Seed oil content varied from 370 to 510 g kg−1 and was depressed by increasing N. Optimum seed and oil yield occurred at about 200 kg N ha−1. Two of the experimental sites responded to S. About 20 kg S ha−1 was adequate for optimum seed and oil yields. At the optimal N and S levels, total plant N, P, K, and S uptake averaged 140, 25, 170, and 60 kg ha−1, respectively. Of the total N, P, K, and S accumulation, about 40% of the N, 30% of the P, and 85% of the K and S remained in the postharvest residue.

Effect of Weed Removal on Productivity of Chickpea (Cicer arietinum L.) and Lentil (Lens culinaris Med.) in a Mediterranean Environment

AbstractThree field experiments were conducted on chickpea (Cicer arietinum L.) and four on lentil (Lens culinaris Med.) at different winter‐sown rainfed locations in Jordan from 1988/89 to 1990/91 to study the effect of the duration of weed‐free and weed‐infested conditions on yields and yield components of the crops. Chickpea seed yields were reduced on average by 81 % and straw yields by 63 % when fields remained weed infested until harvest compared with weed‐free conditions throughout the growing season. The corresponding lentil seed and straw yield decreases were 63 % and 55 %. As the duration of weed‐free period increased and the duration of weed‐infested period decreased, yields increased. However, the critical period of weed interference was between 35 and 49 days after emergence in chickpea and between 49 and 56 days after emergence in lentil, when these crops were at an advanced stage of vegetative growth. There were significant negative correlations between the weed dry weight and the seed or straw yields. The reduction in seed yields in both crops because of weed interference occurred mainly through the reduced number of pods /plant, which in turn was partly the result of reduced number of secondary branches. In chickpea, some reduction also occurred through reduced 100‐seed weight.

Dry matter yield and nutritive value of four summer annual crops in north‐west Spain (Galicia)

AbstractForage production based on summer annual crops is a common agricultural practice in many areas of the world where the growing season is favourable.0An investigation was conducted over 3 years to compare the dry matter (DM) yield and quality of four annual crops; maize (Zea mays L.), sunflower (Helianthus annus L.), sudangrass (Sorghum bicolor L. Moensch) and sorghum (Sorghum bicolor L. Moensch) x sudangrass; in two rainfed locations with different summer temperatures in north‐west Spain (Galicia). The crops were compared at three harvest dates; first weeks of August and September and, except for sunflower, at a later silage stage.The comparative forage yields of each crop varied depending on location and harvesting date, reflecting their suitability for the climate of the location.At Mabegondo, with relatively mild summer temperatures (16.5 °C), maize throughout summer and sunflower until September produced higher DM yields than sudangrass and sorghum × sundangrass. At this location the silage DM yields for maize, sorghum × sudangrass and sundangrass were respectively 15.2, 9.92 and 7.79 t ha−1. At Puebla de Brollón, where the average temperature from June to September was about 2 °C higher than at Mabegondo, the DM production of the sudan‐type crops were similar to maize, while sunflower was significantly lower at the September harvest. The silage DM yields were: maize 14.07 t ha−1 sorghum x sudangrass, 14.05 t ha−1, sudangrass 12–26 t ha−1.The in vitro dry matter digestibility (IVDMD) of maize was always higher than that of the other crops, with an average value of 700 g kg−1.It is concluded that, in north‐west Spain, maize is the most suitable summer crop for maximum yield of good quality forage from the first week of August through to the normal silage stage in October.

Forage production and quality of several crop rotations and pastures in northwestern Spain

AbstractMultiple cropping has been used for many years to increase production in temperate areas of Europe where the growing season is favourable and is important when land area is limiting.The purpose of this 3‐year study was to determine how several different cropping systems affected forage production potential at three rainfed locations in northwestern Spain (Galicia). The cropping systems compared were: single crop maize; double crop systems of maize‐rye, maize oats+ vetch, and maize‐Italian ryegrass; three crops in a two‐year rotation of maize‐Italian ryegrass (12‐months) forage rape; 2‐year pasture maize and two contrasting 3‐year grass‐legume mixtures.There was an increase in dry matter (DM) production as cropping intensity increased. The one‐year double cropping systems always yielded more than three crops in two years, which in turn outyielded single crop maize or 3‐year pastures. The highest DM yields were 20–9 t ha‐1 from the maize‐oats‐I‐vetch rotation. Maize was the principal crop determining total production, yielding about 70% of the total DM for the double cropping systems. The maize component gave similar annual yields in the multiple crop and maize‐pasture rotations, but the use of maize allowed double cropping, which increased production compared with 3‐year pasture.Forage rape gave the highest in vitro dry matter digestibility (IVDMD) of 773–815 g kg‐1 while the oats‐I‐vetch mixture gave the highest crude protein (CP) concentration (105‐217 g kg‐1). The maize crops had the lowest CP content (62‐76 g kg‐1) though digestibility was high (653‐713 g kg‐1).