Browsing by Subject "Sowing date"

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Adaption to rainfall and temperature variability through integration of mungbean in maize cropping
(2021) Khongdee, Nuttapon; Cadisch, Georg
Climate change has threatened global agricultural activities, particularly in tropical and subtropical regions. Rainfed cropping regions have become under more intense risk of crop yield loss and crop failure, especially in upland areas which are also prone to soil erosion. In Thailand, maize is one of the important economic crops and mostly grown in upland areas of northern regions. Maize yield productivity largely depends on the onset of seasonal rainfall. Uncertainty of seasonal rainfall adversely affects maize yield productivity. Therefore, coping strategies are urgently needed to stabilize maize yields under climate variability. In order to identify suitable coping strategies, early maize sowing and maize and mungbean relay cropping were tested on upland fields of northern Thailand. The specific aims of this thesis were (i) monitoring growth and yield performance of maize and mungbean under relay cropping, (ii) testing early maize sowing and maize – mungbean relay cropping as coping strategies under rainfall variations (Chapter 2), (iii) testing effects of relay cropping on growth and yield of mungbean under weather variability (Chapter 4), (iv) determining suitable sowing dates under erratic rainfall patterns by using a modelling approach (Chapter 3), and (v) developing a technique for diagnosis of crop water stress in maize by thermal imaging technique (Chapter 5). Specifically, in Chapter 2 early maize planting or relay cropping strategies were assessed for growth and yield performance of maize under heat and drought conditions. Maize planted in July showed, regardless of sole or relay cropping, low grain formation as a consequence of adverse weather conditions during generative growth. However, July-planted maize relay cropping produced higher above ground biomass than July-planted maize sole cropping and early planting of maize in June. Despite unfavourable weather conditions, maize was, at least partly, able to compensate for such effects when relayed cropped, achieving a higher yield compared to maize sole cropping. June-planted maize sole cropping, however, was fully able to escape such a critical phase and achieved the highest grain yield (8.5 Mg ha-1); however, its associated risk with insufficient rain after early rain spells needs to be considered. Relay cropping showed to be an alternative coping strategy to cope with extreme weather as compared to maize sole cropping. However, relay cropping reduced maize growth due to light competition at young stages of maize before mungbean was harvested (Chapter 2). This negative impact of relay cropping is partly off-set by considering of land equivalent ratio (Chapter 4). Land equivalent ratio indicated a beneficial effect of relay cropping over maize and mungbean solecropping (LER = 2.26). During high precipitation, mungbean sole cropping produced higher yield (1.3 Mg ha-1) than mungbean relay cropping (0.7 Mg ha-1). In contrast to the period of low precipitation, mungbean relay cropping used available water more efficiently and was able to establish its plant, while mungbean sole cropping could not fully withstand severe drought and heat. Mulching effects of maize residues conserved soil water which was then available for mungbean to grow under extreme weather condition. WaNuLCAS modelling approaches can be used to support the decision of maize sowing date in northern Thailand to cope with climate change as indicated by goodness of fit of the model validation (R2 = 0.83, EF = -0.61, RMSE = 0.14, ME = 0.16, CRM = 0.02 and CD = 0.56) (Chapter 3) using forty-eight-year of historical rainfall patterns of Phitsanulok province. Only 27.1% of rainfall probability was classified as a normal rainfall condition. Consequently, maize in this region had faced with high rainfall variability. From long term simulation runs, the current maize sowing date led to strong maize yield variation depending on rainfall condition. Early maize sowing i.e. 15 and 30 days before farmers and staggered planting produced higher yield than current farmers’ practice (mid of July) in most conditions (91.7%). Simulations revealed that water was the most limiting factor affecting maize growth and yield while nutrients (N and P) had only limited impact. Results of the WaNuLCAS model could be used to identify optimal maize planting date in the area prone to soil erosion and climate variation of northern Thailand; however, the model cannot fully account for heat stress. Thermal imaging technique is a useful method for diagnose maize water status. As presented in chapter 5, the developed Crop Water Stress Index (CWSI) using a new approach of wet/dry references revealed a strong relationship between CWSI and stomatal conductance (R2 = 0.82). Our study results established a linear relationship to predict final maize grain yield and CWSI values at 55 DAS as follows “Yield = -16.05×CWSI55DAS + 9.646”. Both early planting of maize and/or relay cropping with legumes are suitable coping strategies for rainfall variability prone regions. The positive response of early planting and legume relay cropping offers the opportunity of having a short-duration crop as sequential crop, providing an additional source of protein for humans and fostering crop diversification on-site. This leads to a win-win situation for farmers, food security and the environment due to an enhanced sustainability of this cropping system.
Lentil production in Germany : testing different mixed cropping systems, sowing dates and weed controls
(2012) Wang, Lina; Claupein, Wilhelm
As a kind of legume crop, lentils (Lens culinaris Medik.) with their high nutritional value are grown mainly for human consumption in many regions of the world. The crop has benefits in crop rotation due to its symbiotic N-fixation, which is important especially in organic farming, and it can also increase crop biodiversity in arable land. In Europe, lentils are considered one of the popular leguminous food crops. However, the cultivation and scientific research on lentils were neglected in Germany and Central Europe over the past 50 years. Recently, farmers have begun to realize the value of lentils and have re-introduced the crop into organic and conventional farming in Central Europe. The lentil plant has a weak stalk and is easily lodging. Lodging plants cannot be completely cut and picked up by combine harvesters, and result in yield loss, especially under the wet conditions that often occur in Central Europe. To avoid lodging of crop, lentils were commonly grown in mixed cropping with cereals, such as oat (Avena sativa L.), barley (Hordeum vulgare L.) and rye (Secale cereale L.). However, there is little current information on lentil cultivation under temperate climates in this region. One of the most relevant challenges for growing lentil is how to explore its yield potential adapt to the local conditions. Moreover, lentil plant has a low competition capacity against weeds which are always one of the big agronomic problems especially on organic farm. Therefore, three field experiments presented in this dissertation were carried out to design and improve lentil cropping systems under organic farming in Germany in terms of productivity and competitiveness performance, suitable species and proportion of companion crops, lentil cultivars, sowing dates, weed control, and seed quality. The results should be used to adapt lentil cropping systems to different local climatic conditions in Germany. The specific objectives were (i) to optimize lentil-based mixed cropping systems through different combinations of companion crops (barley, wheat (Triticum aestivum L.), oat, linseed (Linum usitatissimum L.) and buckwheat (Fagopyrum esculentum Moench)) and mixing ratios, which were expected to show different performance on crop productivity, weed infestation, and lentil lodging, (ii) to determine whether different sowing time (early, medium, late) have effects on a standard lentil-barley mixed cropping system in regard to crop yield and weed control, (iii) to test whether woodchip mulch can help suppressing weeds and increasing crop yield in lentil monocropping and mixed cropping, (iv) to determine whether different mixing ratios affect seed protein content in lentil-cereals (barley, wheat) mixed cropping system. To achieve the first objective, a two-year field experiment of mixed cropping of lentils with five spring-sown companion crops: naked-barley, wheat, oats, linseed and buckwheat was conducted at the organic research station Kleinhohenheim in 2009 and 2010. Besides sole lentil and sole companion crops, three mixing ratios (3:1, 1:1, 1:3) were used. Lentil grain yield was 1.47 t ha-1 in monocropping and 0.58-1.07 t ha-1 in mixed cropping, depending on the mixing ratio and companion crop (Chapter 2). The land equivalent ratio (LER) was higher in mixed cropping than in monocropping generally. Lentil-wheat and lentil-barley mixed cropping with a ratio of 3:1 resulted in the highest LER (ca. 1.50) whereas lentil-linseed had the lowest LER in all ratios. Lowest lodging was observed in lentil-wheat and lentil-oat mixed cropping. Additionally, mixed cropping with ratios of 3:1, 1:1 and 1:3 (lentil: companion crop) reduced weed biomass by 29 %, 41 % and 24 %, respectively, compared with lentil monocropping. The results indicated that lentil mixed cropping in the study seemed more promising than monocropping under the given conditions of the location. Except for the linseed, all tested species can be well used as companion crops especially the two cereals (barley and wheat) which can be recommended. The mixing ratio should consider the total yield advantage (LER), the risk of crop lodging, and marketing considerations of both crops. To achieve the second objective of the study, another two-year (2009-2010) field trial was carried out at two sites: the organic research station Kleinhohenheim (KH) and the conventional research station Oberer Lindenhof (OLI) (Chapter 3). The crop was sown at three dates (early, medium and late) in the period from March to May. Four genotypes of lentil: Anicia, Schwarze Linse, Hellerlinse and Berglinse were mixed-cropped with naked-barley at a ratio of 3:1 (lentil:barley) at each sowing date. Results showed that grain yield of crops was significantly higher at the earliest sowing both for lentils (3.0 t ha-1 at KH, 2.4 t ha-1 at OLI) and barley (1.2 t ha-1 at KH, 2.6 t ha-1 at OLI). Lentil seed per plant, barley seed per ear, and thousand kernel weight of crops decreased significantly with delayed sowing. At KH experimental site, weed biomass increased significantly with delayed sowing and was independent of the lentil genotype, whereas sowing date had no significant effect on overall weed biomass production at OLI. The results indicated that early sowing can increase the yield of lentils, and can also be used as an indirect method of weed control in organic farming. To further control weeds to achieve the third objective, a field experiment of applying woodchips mulch on lentils was carried out at the organic research station Kleinhohenheim, in the years 2009 and 2010 (Chapter 4). Two years on average, an amount of 160 m3 ha-1 (fresh matter) woodchips mulch reduced weed biomass and weed density in both cropping systems compared to no mulch treatment, with a reduction by 43 % and 29 % (sole), and by 51 % and 30 % (mixed) respectively. Mixed cropping of lentils with barley (3:1) also decreased weed biomass compared with lentil sole cropping; however, no effect on weed density was observed. Lentil grain yield from sole and mixed cropping was 3.0-3.4 t ha-1 and 2.1-2.2 t ha-1 (2009), and 1.0-1.1 t ha-1 and 0.8-0.9 t ha-1 (2010). Barley grain yield was 1.4 t ha-1 in 2009 and 0.7 t ha-1 in 2010. Despite decreasing weeds, the mulch did not improve crops grain yields in mixed or sole cropping. The combination of woodchip mulch and mixed cropping is useful to reduce weed infestation in cropping systems where chemical or mechanical weed control is not possible and for crops with a low capacity for competition against weeds. Another focus of the study was on seed quality (protein content), especially for the cereals (Chapter 5). The two mixed cropping systems: lentil-wheat and lentil-barley with five seeding ratios (4:0, 3:1, 1:1, 1:3, 0:4) were tested at the organic research station Kleinhohenheim in 2009 and 2010 (originated from the experiment 1). Results showed that cereal grain protein increased significantly when their proportion was reduced in the mixture with lentils. Wheat crude protein increased from 10.3 % (2009) and 11.0 % (2010) in monocropping to 11.5 % (2009) and 15.1 % (2010) in mixed cropping with 75 % lentils. Barley crude protein increased in the same way from 13.7 % in monocropping to 15.8 % in mixed cropping with 75 % lentils. However, lentil protein content did not differ significantly across all mixing ratios. Total crude protein in a mixture was significantly higher than that in cereals or lentils monocropping. Mixed cropping with lentils can thus be an option to obtain a high protein content of wheat which is important for a suitable breadmaking quality, particularly in organic farming. Summarizing, the overall results of the study will open new options for growing lentils in Central Europe from where the crop has vanished over the last decades and may guide the future of lentil production in multi-cropping.