Termos para indexação: Phaseolus vulgaris, balanço hídrico do solo, drenagem, sonda de nêutrons.
Evapotranspiration of irrigatedcommonbeanunder no-tillage on differentcovercropmulches
Abstract – The objective of this work was to determine the effect of differentcovercropmulches on the evapotranspiration of irrigatedcommonbean cultivar Pérola. The experiment was carried out during two years, 2002/2003 and 2003/2004, at Embrapa Arroz e Feijão, in Santo Antônio de Goiás, GO, Brazil, on a Rhodic Haplustox, in a randomized block design, with four replications. In the first year, the treatments consisted of seven cover crops grown under no-tillage: Brachiaria brizantha cv. Marandu; corn (Zea mays L.) associated with B. brizantha; pigeon pea (Cajanus cajan (L.) Millisp); millet (Pennisetum glaucum (L.) R. Br. cv. BN-2); Panicum maximum cv. Mombaça; sorghum (Sorghum bicolor (L.) Moench cv. BR 304); and Stylosanthes guianensis cv. Mineirão. In the second year, it was added another covercrop, Crotalaria juncea L. The evapotranspiration during the commonbean cycle was determined using the field water balance methodology, and it ranged from 259.8 to 343.7 mm, depending on the covercrop and year. B. brizantha and P. maximum mulches, due to their highest dry weights, provided the lowest water losses through evapotranspiration. The highest differences among cover crops related to commonbeanevapotranspiration occurre in the initial and later stages of bean cycle.
Laikipia County, like other parts in ASALs is predominantly characterised by low and variable rainfall, which rarely exceeds 750 mm. This amount is sufficient average rainfall to sustain crop growth if only it is well distributed over the crop life to obtain good yields. However, yields of most crops are known to be greatly reduced by periods of more than 10 consecutive dry days at critical growth stages of the crop which has become common with changing weather patterns in Laikipia. The high temperature (16 -26 o C) experienced in the county increases evapotranspiration leading to high moisture losses further compromising the amount of water available for crop growth. There has been erratic weather patterns leading to frequent floods and droughts, (Laikipia County Integrated Development Plan [LCIDP], 2013) resulting in crop failure recorded in one out of every three seasons (Laikipia Wildlife Forum [LWF], 2013). Common beans require good tillage that ensures there is sufficient soil volume available to the roots to permits water percolation. The soil should also be well aerated. The production of common beans is constrained by among other things, tillage methods. In Laikipia County, the common practice in land preparation among small scale farmers is manual digging. This method does not prepare land appropriately or in time. The method is tedious, time consuming and does not go deep enough to break hardpans that may be present in the soil. There is limited information on alternative methods of land preparation for bean production in Laikipia County. Some of the methods like herbicide use are not friendly to the environment and are expensive to sustain. Others like minimum tillage are limited by the amount of area that can be prepared within a given period of time. It is for this reason that this experiment was designed to evaluate the effects of tillage methods on growth
The experimental design was a split plot with two factors and 3 replicates. The main factor studied was the planting method of the cover crops: direct seeding after maize harvest with no- tillage (DS) or seeding after soil preparation with conventional tillage operations after maize harvest (CT). Direct seeding allowed earlier planting dates, the soil was untilled, and the previous maize residue was on the soil surface. On the other hand, seeding after conventional tillage had later planting dates and the soil was tilled with the maize residue incorporated into the soil. These are the differences between the two planting methods under real field conditions and this is what we tested. The second factor studied was the different winter covercrop species: winter barley (Hordeum vulgare L., cv.Hispanic), oilseed rape (Brassica napus L., cv. Madrigal), winter rape (Brassica rapa L., cv. Perko), common vetch (Vicia sativa L., cv. Armantes), and a control treatment with bare soil during winter. The size of each experimental plot was 6 m by 18 m.
As the world is experiencing increasing population, so is the increasing demand for food hence, the need to open more lands arises. This must be done in such a way that soil degradation is avoided in that, the soil is prepared to serve as a sink rather than a source of atmospheric impurities. However, it is based upon the avoidance of the soil being a source of atmospheric pollutants that conservation tillage along with some complimentary practices such as soil cover and crop diversity , argues that conservation tillage is a component of conservation agriculture (CA) , propended that conservation tillage system can increase water use efficiency by 25-40%. However, little information on how conservation tillage influences the water use efficiency (WUE) of drought tolerant crops with short maturation period, such as beans is limiting our understanding on the importance of such practices in improving the production of drought tolerant commonbean varieties. Despite these limitations, conservation tillage is still efficient in the maintenance of surface soil cover through retention of crop residues achievable by practicing zero tillage and minimal mechanical soil disturbance . This study seeks to compare effects of tillage practices on WUEs and yields of drought tolerant bean varieties in Machakos County using three tillage systems CT, MT and ZT along with four varieties GLPX92, KATX56, KAT/B1 and KATRAM.
Commonbean (Phaseolus vulgaris L.) stands out as one of the main crops produced in Brazil, an agricultural product extremely appreciated by Brazilians. Planting of crops associated with irrigation is a viable alternative, among cultural practices, in improving productivity. The objective of this study was to verify the effect of the presence and absence of dead cover (surface straw) and of different irrigation slides on the development and productivity of the beancrop. The soil used does not present evident erosion, with very small granular structure, very porous, soft, friable, plastic and sticky, excessively drained consistency, being classified as Red Latosol Eutrophric typical clay texture. The experimental design was divided into sub-divided plots, with four replications, with two plots with and without mulch on the surface, and subplots with 5 irrigation slides: 25, 50, 75, 100 and 125% of daily real evapotranspiration. To evaluate the productive agronomic characteristics, only the two central rows of each plot were considered as useful area, scoring 0.5m at each end. The evaluated parameters were: fresh mass, number of grains, number of pods, mass of 100 grains, production. Quantitative data were submitted to analysis of variance (ANOVA), followed by regression analysis. Conventional planting presented lower results than no - tillage in the characteristics evaluated, except for the production that obtained very similar values in both systems of planting. The no-tillage system provided better yields for the bean development, so that 100% irrigation would be recommended for the farmer.
Abstract – Nitrogen is an essential nutrient to commonbean and its shortage is observed in almost all types of soils. The objective of this work was to evaluate the performance of irrigatedcommonbean grown under no-tillage in succession to differentcover crops and in relation to nitrogen topdressing fertilization in a Dystrophic Red Latosol (Typic Hapludox). The treatments were seven cover crops: Brachiaria brizantha cv. Marandu, B. brizantha associated with corn (Zea mays L.), pigeon pea (Cajanus cajan L. Millisp), millet (Pennisetum glaucum L. R. Br.), Panicum maximum cv. Mombaça, sorghum (Sorghum bicolor L. Moench) and Stylosanthes guianensis cv. Mineirão. The beancrop (cv. Perola) was seeded on the covercrop and 0, 30, 60, and 120 kg ha -1 of N (urea) were topdressed. The cover crops affected the commonbean grain yield. The highest grain
Soil N (nitrate and ammonium) concentrations in GSF subplots peaked 30 dap, but were higher than other treatments 90 dap. The high rate CRF subplots appeared to delay peak release of N until 60 dap, but had lower N 90 dap than the GSF subplots. The inorganic nitrogen decline across time in GSF and low rate CRF subplots is likely from crop uptake. However, GSF subplots had higher inorganic nitrogen peaks, and the greater nitrogen remaining in the soil at the last sample period could have been an effect of the lower plant population in GSF subplots.
week before covercrop termination as influenced by covercrop with tillage (CC-Till), no covercrop with tillage (NC-Till), covercrop with no till (CC-NT), and no covercrop with no till (NC- NT) treatments. Note: Pore size classes include; macropores (> 1000 µm diameter), coarse mesopores (60-1000 µm), fine mesopores (10-60 µm diameter), micropores (< 10 µm diameter). Bar indicates least significant difference (0.05) value for pore size distribution. .......................... 78 Figure 4.1 The Parlange and Green-Ampt (G&A) models fitted to measured ponded infiltration data for
The effects of tillage, crop rotation, covercrop and depth of sampling on soil physical properties for the second year (2012) are shown in Table 3. Significant covercrop x depth of sampling interactions (p<0.05) were found for BDY, Ds/ Do, GWC and TPS. In addition, there was a significant crop rotation x depth of sampling interaction for GWC (p<0.05). The interaction between covercrop and depth of sampling is presented in Fig. 2 for BDY and TPS, respectively. They suggest that the benefits of the covercrop (rye) roots in de- creasing soil bulk density (reducing soil compaction) and increasing total porosity were more prominent in the top 10 cm of the soil. At deeper depths (20-60 cm), the influ- ence of rye is no longer felt since BDY and TPS were higher in rye planted plots as compared to no-rye plots. This is understandable, since most rye roots were concen- trated in the 0-10 cm depth. Our results agree with those by Villamil et al. (2006) who reported similar findings. The covercrop x depth of sampling interaction showed that Ds/ Do was 25% (0-10 cm) and 14% (10-20 cm) greater in plots planted to rye as compared with plots with no covercrop. This same interaction also showed that GWC was 10% greater in covercrop compared with no covercrop plots in the 10 cm layer of the soil. Blanco-Canqui et al. (2011) also reported a 4% increase in soil water content with covercrop. These results suggest an improvement in bio-pores which have been reported to increase water retention and infiltration (Bruce et al., 1992; Joyce et al., 2002; Wilson et al., 1982) and to reduce runoff and soil loss. However, T a b l e 1. Means for soil texture at four depths in a silt-
Faculty of Agriculture, University of Adnan Menderes, 09100 Aydin, Turkey.
The cotton growing in Turkey has monoculture system and any crop is not grown in approximately five months between two cotton growing which caused lower seed cotton yield, poor lint quality and early leaf senescence. The influences of differenttillage systems and winter cover crops on cotton lint yield and quality were evaluated in Aegean Region of Turkey during two cotton-growing seasons. In second year compared to the first year, the dry matter yield of covercrop root residues increased by 40% in conventional tillage system and 60% in no tillage system. Similar increases were also determined for residue organic matter yield in soil. Dry matter and organic matter in soil harvest residues were higher in conventional tillage system as compared to no tillage system. Among covercrop treatments common vetch + oat and hairy vetch + oat mixtures provided the highest dry matter and organic matter in soil harvest residues. Cotton lint yield and quality were not affected by covercrop treatments and tillage systems. Also, tillage by covercrop interactions was non-significant for cotton lint yield and quality. During the observations at 50% boll opening period of cotton, it was monitored that leaf senescence decreased under no-tillage cotton production system in both years.
Soil properties were analyzed by depth (0–5 cm and 5–15 cm) with four replications for each increment. Individual soil properties were evaluated with mixed-effects ANOVA models in R (R Core Team, 2016) with field and replicate as random effects and tillage and residue removal as fixed effects. The interaction term for tillage × stover removal was included. This method com- pared soil effects for all treatments except for those with cover crops. Separately, covercrop effects were tested by conducting the same type of analysis using only no-till treatments with moder- ate or high stover removal rates in the comparison. Fixed effects for covercrop and stover removal (moderate or high only) were evaluated in this second series of analyses. In the results and dis- cussion for this second set of analyses, only covercrop effects are discussed because this was the primary effect of interest. To assist in presentation and discussion, the results from NT35 and NT60 are repeated in the tables, as they were included in the statistical analysis of both datasets. All treatment effects were evaluated with P < 0.1. The tables report the mean value for each soil prop- erty and the text includes the mean value and SE. The CV was calculated for each soil property to show sample variability and help interpret the statistical results. The SD was divided by the mean and multiplied by 100 to express the CV as a percentage.
At different points throughout the growing season SPAD and NDVI readings were taken and along with ear leaf N concentration, provide indicators of crop N status; Table 7 summarizes this data. Plant chlorophyll and canopy cover were measured using a SPAD meter and hand-held Greenseeker ® technology. As a general rule SPAD readings increased with N application, as one would expect with the exception of the three-year rotation CT covercrop plots. We see that CT plots in 2014, with a very wet June, tend to have higher SPAD readings at V6-V8 than did NT plots, indicating a greener leaf with more N in the plant at the time of reading. This difference appears to be lessened, or lost, by the R1 stage as there was no clear trend for ear leaf N in the two-year rotation data, nor was this trend observed in 2015. In addition, rotation and covercrop treatments appeared to have very little effect on SPAD readings.
All material supplied by Trinity College Library is protected by copyright (under the Copyright and Related Rights Act, 2000 as amended) and other relevant Intellectual Property Rights. By accessing and using a Digitised Thesis from Trinity College Library you acknowledge that all Intellectual Property Rights in any Works supplied are the sole and exclusive property of the copyright and/or other I PR holder. Specific copyright holders may not be explicitly identified. Use of materials from other sources within a thesis should not be construed as a claim over them.
12 management of irrigation quantity along with the rate and timing of nutrients application are of critical importance to obtain desired results in terms of productivity and nutrient use efficiency (Jat et al., 2011). A good soil management programme protects the soil from water and wind erosion, provides a good, weed-free seedbed for planting, destroys hardpans or compacted layers that may limit root development, and allows maintenance or even an increase of organic matter (Ali et al., 2018). Use of excessive tillage is often harmful to soil. Therefore, currently there is a significance interest and emphasis on the shift to the conservation and no-tillage methods for the purpose of controlling erosion process (Adugna, 2019). Tillage is an effective farm activity to improve soil tilth and soil physical conditions (Khan et al., 2010).
Water relations are among the most important physical phenomena that affect the use of soils for agricultural, ecological, environmental, and engineering purposes. In sub-Saharan African, water is most critical in limiting crop production and yields especially in the Arid and Sub-arid regions. The soil water storage, available water content and soil water balance under various covercrop residue management practices in a Nitisol were evaluated in a field experiment at the Kabete Field Station, University of Nairobi. The effects of surface mulching, above and below ground biomass and roots only incorporated of velvet bean (Mucuna pruriens), Tanzanian sunhemp (Crotalaria ochroleuca) and purple vetch (Vicia benghalensis) cover crops, fertilizer and non fertilized plots on soil water balance were studied. The experimental design was a split plot and tomato (Lycopersicon esculentum) was the test crop. Since water content was close to field capacity, the drainage component at 100 cm soil depth was negligible and evapotranspiration was therefore derived from the change in soil moisture storage and precipitation. Residue management showed that above and below ground biomass incorporated optimized the partitioning of the water balance components, increasing moisture storage, leading to increased tomato yields and water use efficiency (WUE). Furthermore, vetch above and below ground biomass incorporated significantly improved the quantity and frequency of deep percolation. Soil fertilization (F) and non fertilization (NF) caused the most unfavourable partitioning of water balance, leading to the lowest yield and WUE. Tomato yields ranged from 4.1 in NF to 7.4 Mg ha -1 in vetch treated plots. Vetch above and belowground biomass incorporated had significant (p ≤ 0.1) yields of 11.4 Mg ha -1 compared to all other residue management systems. Vetch residue treatment had the highest WUE (22.7 kg mm -1 ha -1 ) followed by
The average soil moisture content (Wc) for all variants, depths and years was 25.19%. The average moisture for all investigation years and depths per particular tillage systems ranged from 23.43% (CT), 23.68% (RT), 25.30% (CP), 25.95% (CM) to 27.59% (NT). Statistically signifi- cant differences were recorded between NT and CT or RT tillage systems. Based on the differences in average moisture values of all depths among particular tillage systems for each year separately, significant differences were recorded for soybeans grown in 1997 between NT and CT, RT or CP systems. Similar results were also ob- tained for soybeans grown in 1999, where significant dif- ferences were recorded between NT and CT or RT, as well as between CT and CM tillage systems. Differences in average moisture values recorded for winter wheat of both growing seasons are significant only between NT and CT or RT tillage systems. The lowest average mois- ture content of all years per particular tillage systems at the depth of 05 cm was determined in CT and at 1520 and 3035 cm in RT, while the highest moisture content at all three depths were recorded in NT system. At the depth of 05 cm the recorded difference is significant only between NT and CT, at the depths of 1520 and 30 35 cm between NT and CT or RT tillage systems. Aver- age soil moisture values of all years point to the trend of increased moisture in NT and CM tillage systems com- pared to CT and RT systems. Statistically significant dif-
5 S YNTHESIS , C ONCLUSIONS AND R ECOMMENDATIONS
In this study, subsoiling improved the soil conditions for plant growth by reducing soil density and strength, and improved water infiltration capacity of the soil. Potential benefits that may arise include less ponding of water on the soil surface, better aeration and conditions for root growth (Aase et al, 2001; Bengough and Mullins. 1990). However, the grain yield response that was observed on the different soils over the course of this study was small and variable, with average yield benefits from sub-soiling only averaging out to be about 5%. These results are similar to that reported in past research in prairie soils and elsewhere. (Mermut et al, 1992; Grevers and de Jong, 1992; Grevers and de Jong, 1993; Hamilton-Manns et al., 2002; Wang et al., 2009). The optimum configuration for sub-soiling with the paraplow in terms of alteration of soil properties and improvement of crop yield was the conventional, normal recommended configuration of 45 cm shank spacing and 45 cm depth. Wider spacing and shallower depths generally had no, or negative effects, compared to the control. Small differences were observed when comparing the spring and fall timing of tillage. Subsoil tillage is reported to be most effective in normal to dry soil conditions (Grevers and de Jong, 1993) as long it not so dry as to cause soil surface disturbance or greatly increase the draft requirement to pull the equipment. Lower soil moisture levels are typically observed in the fall. While drier conditions typically encountered in fall may be more conducive for effective soil loosening, the freeze-thaw and wet- dry cycles between fall tillage and seeding in the spring maybe sufficient to degrade some of the tillage effects. Producers may find greater success with either depending on soil conditions. It is recommended that future work be conducted on evaluation of subsoiling under drier conditions than those encountered in the current study.
There is a growing interest among growers to utilize production techniques that reduce soil erosion, minimize nutrient leaching, suppress weed emergence, and build soil quality and organic matter. Cover crops are now being widely used by both conventional and organic growers to accomplish these tasks and also to maintain high soil fertility. Cover crops have a profound impact on soil quality by adding to the soil organic matter pool, enhancing soil structure and fertility, improving soil water holding capacity, reducing the loss of nutrients and sediments in surface run-off, and suppressing weed populations. Additional beneﬁts from cover crops include reduction of insect and disease spread, enhanced microbiological attack of soil pathogens, increase in soil microbial biomass, and biological activity.
The conventional sowing practices are one of the reasons for low crop yield in the country (Khan et al., 1990). To mechanize sowing operation, a suitable drill should be used to place the seed and fertilizer in the zone of adequate moisture and at desired depth. Singh et al. (2007) reported that strip till drilling produced higher values of growth, yield attributing characters, grain and straw yield as compared to conventional sowing methods. Keeping in view the importance of tillage practices and sowing methods, the present research study was conducted to evaluate the performance of differenttillage practices, sowing methods and their effect on weed biomass and yield of mungbean underirrigated condition.