- Authors:
- Muchaonyerwa, P.
- Chiduza, C.
- Dube, E.
- Source: Soil & Tillage Research
- Volume: 123
- Year: 2012
- Summary: A study was conducted to determine the effects of oat (Avena sativa) and grazing vetch (Vicia dasycapa) winter cover crops and fertilization regimes on soil organic matter (SOM) in an irrigated maize-based (Zea mays L.) conservation agriculture (CA) system following four years of continuous practice. Separate plots of oat and grazing vetch cover crops were grown in winter and then maize was planted in all plots in the following summer season. The four fertilization regimes used were: (i) fertilizer applied to the cover crops and the maize crop (F1), (ii) fertilizer applied to cover crops only (F2), (iii) fertilizer applied to the maize crop only (F3) and (iv) no fertilizer applied (F4). Control plots (weedy fallows) were included and the treatments were laid out in a randomized complete block design with three replications. Soil samples from 0-5, 5-20 and 20-50 cm depths were analyzed for total SOM, particulate organic matter (POM) fractions, hot water soluble C (HWC) and C-associated with water stable macro- and micro-aggregates (WSAC). While total SOM was more concentrated in the 0-5 cm soil depth across treatments, a lack of maize fertilization (F2 and F4 regimes) significantly (P
- Authors:
- Haghighi, B. J.
- Miri, H. R.
- Ebrahimi, S. M.
- Source: Advances in Environmental Biology
- Volume: 6
- Issue: 4
- Year: 2012
- Summary: The purpose of this study was evaluating the growth and compare yield and water consumption of corn under treatments of conventional tillage, reduced tillage and no tillage during the different irrigation intervals. This study was conducted at Arsanjan city, southern Iran in 2009. The experiment was split plot in randomized completely blocks design with three tillage methods (conventional tillage without residues, minimum tillage and conservation residues, and no tillage and reserve residues) as main factor and irrigation intervals (8 days, 11 days and 14 days intervals) as sub factor with four replication. Result of this study showed that 8 days irrigation interval and conventional tillage produced the highest grain yield, biological yield, ear number, seed number and seed weight in comparison with other treatments. But, by increasing irrigation interval to 14 days and decreasing water usage, no tillage and reserve residue treatment could prevent reduction in grain yield. In general results showed that residues management by reserving residue as a surface cover and improves tillage method to minimum and no tillage can increase corn yield through improvement soil organic carbon which is the main goal in conservation agriculture. We can reach to economic corn yield by reducing irrigation times and saving water usage in warm and dry regions, so it is possible to plant corn in this area directly in residue of previous crop.
- Authors:
- Hellin, J.
- Wall, P.
- Sayre, K.
- Erenstein, O.
- Dixon, J.
- Source: Journal of Sustainable Agriculture
- Volume: 36
- Issue: 1-2
- Year: 2012
- Summary: Conservation agriculture's underlying principles-minimal soil disturbance, soil cover and crop rotation-are increasingly recognized as essential for sustainable agriculture. This article summarizes three contrasting cases of adapting conservation agriculture (CA) to smallholder conditions in the (sub)tropics: a) irrigated rice-wheat systems in South Asia; b) rainfed maize/wheat and irrigated wheat systems in Mexico; and c) rainfed maize in Southern Africa. In the South Asia case, farm surveys show rapid and widespread adoption of zero tillage wheat-primarily due to a substantial cost saving (15-16%). In the other cases, uptake so far has been limited-although long-term trials show continuously higher and more stable yields both for maize and wheat. Under marginal conditions CA can generate substantial yield increases-averaging some 50% over conventional smallholder maize yields of 1 ton per ha over 6 years in on-farm trails in Southern Africa. The diverse experiences attest to the wide adaptability of CA systems, which can generate clear economic and potentially enormous environmental benefits. The case studies and wider literature however also reiterate the substantial challenges in terms of targeting, adapting and adopting CA-particularly for smallholders in the (sub)tropics. CA systems are best developed in situ through a multi-stakeholder adaptive learning process to create viable CA-based options that are technically sound, economically attractive, and socially acceptable.
- Authors:
- Kadyampakeni, D.
- Fandika, I. R.
- Zingore, S.
- Source: Irrigation Science
- Volume: 30
- Issue: 1
- Year: 2012
- Summary: The performance of a bucket drip irrigation system (BDI) powered by treadle pump was evaluated on tomato and intercropped maize/bean crops, between 2005 and 2007 in Malawi. It was a split plot experiment with three replicates. The BDI system consisted of a 1,300-l tank mounted 1.5 m above ground and connected with a 32-mm mainline and 15-mm lateral lines spaced at 1 m by 0.6 m. A treadle pump was used to uplift water to the tank. Tomato and intercropped maize/bean were irrigated every 4 days. The system reduced labour and water by >25% and it showed high uniform application depth and wetted diameter. Yields were significantly different between tomato varieties ( P
- Authors:
- de Ridder, N.
- Vanlauwe, B.
- Pypers, P.
- Guto, S. N.
- Giller, K. E.
- Source: Agronomy Journal
- Volume: 104
- Issue: 1
- Year: 2012
- Summary: Soil fertility gradients develop on smallholder farms due to preferential allocation of inputs. A multi-location on-farm trial was conducted in Meru South, Central Kenya whose overall aim was to test minimum tillage and crop-residue retention practices in socio-ecological niches across heterogeneous smallholder farms. We identified three soil fertility classes together with the farmers, namely: good, medium, and poor. In each soil fertility class, two tillage (minimum or regular) and two crop residue (removed or retained) practices were tested for four consecutive seasons. Maize (Zea mays L.) grain yields in the good fields were above 2.5 Mg ha(-1) across cropping seasons and cumulated yields were not influenced by tillage or crop residue management. The grain yields in the medium fields ranged between 1.3 and 5.4 Mg ha(-1) and were greater with crop residue retention. In the poor fields, grain yield was
- Authors:
- Ribeiro, L.
- Mendes, M. P.
- Silva, E.
- Cerejeira, M. J.
- Source: Environmental Science & Pollution Research
- Volume: 19
- Issue: 7
- Year: 2012
- Summary: Purpose: To assess groundwater exposure to pesticides, in agricultural areas of 'Ribatejo' region (Portugal), and the influence of some key factors in that exposure, field, laboratory and modelling studies were carried out. Methods: The study was performed in maize, potato, sugar beet, tomato and vegetables agricultural areas, located in a shallow aquifer, with pesticides use and, in most cases, with irrigation practices. Pesticides used in the studied agricultural areas and having leaching potential were selected, being considered also other pesticides included in priority lists, defined in Europe. Evaluation of groundwater exposure to pesticides was carried out by successively: (1) groundwater sampling in seven campaigns over the period 2004-2006; (2) pesticide analysis [including isolation and concentration from the groundwater samples and further determination by gas chromatography-mass spectrometry (GC-MS) of 14 herbicides, four insecticides and two metabolites]; and (3) analysis and discussion of the results by applying joint correspondence analysis (JCA). Results: From the 20 pesticides and metabolites selected for the study, 11 were found in groundwater. Pesticides and metabolites most frequently detected were atrazine, alachlor, metolachlor, desethylatrazine, ethofumesate, alpha-endosulfan, metribuzine, lindane and beta-endosulfan. The results showed that groundwater exposure to pesticides is influenced by local factors - either environmental or agricultural, as precipitation, soil, geology, crops and irrigation practices. Spring and autumn were more associated with the detection of pesticides being more likely to observe mixtures of these compounds in a groundwater sample in these transition seasons. Conclusions: This work evidences the importance of models, which evaluate pesticides environmental behaviour, namely their water contamination potential (as Mackay multicompartimental fugacity model) and, specially, groundwater contamination potential (as GUS and Bacci and Gaggi leaching indices), in pesticide selection. Moreover, it reveals the importance to adapt proper statistical methods according to level of left-censored data. Using JCA was still possible to establish relations between pesticides and their temporal trend in a case study where there were more than 80% of data censored. This study will contribute to the Tagus river basin management plan with information on the patterns of pesticide occurrence in the alluvial aquifer system.
- Authors:
- Source: Journal of Cotton Research and Development
- Volume: 26
- Issue: 1
- Year: 2012
- Summary: Field experiment was conducted at Cotton Research Station, Srivilliputtur during 2005-2008 to study the response of summer irrigated cotton to the preceding crop, residue management and INM practices. The results revealed that maize as a preceding crop was advantageous with its stalk incorporated with the highest seed cotton yield of 1573 kg/ha and was comparable with maize as a preceding crop with stalk removed. With regard to INM practices, application of 100 per cent RD of fertilizers+azophos registered the highest seed cotton yield and was comparable with 75 per cent RD of fertilizers+azophos, 100 per cent RD of fertilizers+FYM and 100 per cent RD of fertilizers alone indicating that 75 per cent RD of fertilizers+azophos was optimum to get economic yield.
- Authors:
- Source: Journal of Food, Agriculture and Environment
- Volume: 10
- Issue: 2
- Year: 2012
- Summary: Panzhuang Irrigation District is one of the Yellow River irrigation areas. The spatial and temporal distribution of water resources is severely uneven in the upper, middle and lower reaches of the irrigation district. In order to solve this problem, it is necessary to study the differences of crop water consumption (evapotranspiration-ET), irrigation amount, soil water and water use efficiency (WUE) of winter wheat, summer maize and cotton which are the main crops in the irrigation district. This paper improved calculating methods of the capillary rise and percolation of the established model. The model was then applied to the upper, middle and lower reaches of the irrigation district. Conclusions by the model simulation were as follows: (I) The model could simulate the dynamics of water balance components of wheat-maize and cotton relatively accurately in the irrigation district. (II) Winter wheat and summer maize (wheat-maize) had the highest ET in the upper reaches, followed by the middle reaches and then the lower reaches. There was almost no difference for cotton ET in the upper, middle and lower reaches. (III) Irrigation amount of wheat-maize was 225-300 mm in the upstream, 300 mm in the middle reaches, and 500 mm in the downstream. Cotton irrigation quantity was 60-150 mm in the upper and middle reaches, and 60-390 mm in the lower reaches. (IV) Soil water basically showed a decreasing trend in growth periods of wheat-maize and cotton in the middle and lower reaches, its recharge was primarily from irrigation of wheat. Combined with other references, there was a trend of soil drying in the North China Plain. (V) Mean values of water use efficiency (WUE) of winter wheat, summer maize and cotton were highest in the middle reaches and lowest in the upstream and downstream.
- Authors:
- Source: Advances in Environmental Biology
- Volume: 6
- Issue: 4
- Year: 2012
- Summary: In most areas of Isfahan Province, the maize is cultivated as a second crop after harvesting the wheat or barely and the farmers of this region are confronting with time-limit problems in performing correct yield of providing the soil bed, and the tillage is an expensive and energy-consuming yield. Thus, for examining the effect of tillage on the elimination of mechanical yield and saving the time and the expense of performing yield as well as the effect of appropriate date for planting the maize on the performance and its components, an experiment is conducted as a split plot design, 4 times in the agricultural year 2010 in Mourchekhort area of Isfahan. The factors including tillage in two levels (Current Tillage "CT" and Non-tillage "NT") on the main plot and the planting date in three levels (29 th June-15 th July-28 th July) with 15-day interval on the secondary plot were operated on the maize sort No. I704. The tillage system is not significantly effective on the biological performance. In tillage system, the performance of the grain, the number of corns in the maize row and the total number of corn in the maize showed respectively 10%, 12% and 22% increases, compared to those in nontillage system. On 29 th June, the weight of one-thousand corns was decreased 13% and the performance of the corn, the number of corns in the maize row and the total number of corns in the maize was respectively increased in 35%, 16% and 30% compared to those on 29 th July. Reciprocal effect of tillage system and planting dates didn't effect on the corn's performance and its components. Considering the results achieved, the best planting date for both tillage systems in this area is 29 th June.
- Authors:
- Coquet, Y.
- Justes, E.
- Benoit, P.
- Alletto, L.
- Source: Agriculture, Ecosystems & Environment
- Volume: 153
- Year: 2012
- Summary: Water drainage and herbicide degradation and leaching were studied during four years in a continuous maize field managed with two tillage systems and two types of fallow periods. The tillage systems consisted of either a conventional practice with mouldboard ploughing (28 cm-depth) or a conservation practice with superficial tillage (
