Choosing soil management systems for rice production on lowland soils in South Brazil

Lowland soils are commonly found in the state of Rio Grande do Sul, Southern of Brazil, where they represent around 20% of the total area of the state. Deficient drainage is the most important natural characteristic of these soils which therefore are mainly in use for flood-irrigated rice (Oriza sativa). Degradation in these soils is progressively getting stronger since the intensity of agricultural activities leads to a higher soil density, and a lower water infiltration rate. There is a growing interest by farmers to grow other crops such as soybean in rotation with rice but this degradation has become an obstacle to do so. Soil analyses have showed differences in physical, chemical and biological properties as a result of management practices adopted by farmers. This paper shows how a soil management system was chosen by farmers in relation to irrigation and drainage constraints. Parameters were considered by farmers: soil type, (expected changes in) quality of soil structure, choice of machinery, farm size, management level, labor, inputs in terms of fertilizer and pesticides, opportunities for rotation with crops other than rice. The three management system currently in use (Conventional, Semi-direct and Pre-germinated), are taken as examples. The study showed that although farmers are well aware of potentially better management systems when considering soil quality, they were often (especially the small farmers) forced to reject the choice for the best system

Design and evaluation of a no-tillage seeder for small scale vegetable production using a two-wheeled tractor in Coahuila, Mexico

Currently used conventional tillage systems for small-scale vegetable production in the region of Saltillo, Coahuila, Mexico require a considerable amount of hand labor, energy and materials for all activities. Seedbed preparation can require up to 60% of the total production cost in some systems in Mexico. Further, soil is degraded and eroded due to the system. Conservation tillage may reduce costs and prevent soil degradation, but appropriate tools, such as, no-tillage seeders for small-scale farmers are not available. This papers reports on the design and construction of a prototype of a no-tillage seeder for small-scale conservation tillage using a 2-wheeled tractor. Three main functions received particular attention: opening of the soil, placing seed and/or fertilizer and closing the slot. Because of its vapor conservation and good seedling emergence, tools to create T-shaped slots were chosen, with adapted depth control and closing and covering devices. A systematic design process was applied in order to reach the required decisions. Function diagrams were defined from where morphologic charts guided the selection of the configuration of the seeder. A preliminary evaluation included testing of two furrow opener disc types (notched and fluted), and four crop residue levels, 0, 30, 60 and 100%, with respect to performance of the seeder. An evaluation showed that with low cover amounts a consistent and firm seed cover was obtained, but emergence quality decreased due to insufficient residue cover. The notched disc had a better performance than the fluted disc. The inverted T-shape in the soil was not always sustained due to technical flaws. It was possible to build a prototype under 2000 dollars with basic tools in a local workshop. Further research will focus on the biological performance and improvement of the mechanical components and performance

Research on a special scarifier mechanism with finite element analysis method

Abstract—A scarifier mechanism with rotary tillage and antirotary grubbing is proposed for inducing the power of tillage in hardens soil. MAT147 material modal is amended by experimental method and soil high-speed cutting finite element modal is build through SPH method, further, the tools parameter of proposed mechanism and soil cutting speed are studied by FEA numerical simulation through orthogonal experiments method. Finally, the result shows that the proposed mechanism with proper structural parameters and work speeds can reduce the requirement of power of tillage and increase the working efficiency of small agricultural machinery

Dryland maize yields and water use efficiency in response to tillage and nutrient management practices in China

Rainfed crop production in northern China is constrained by low and variable rainfall. This study explored the effects of tillage and nutrient management practices on maize (Zea mays L.) yield and water use efficiency (WUE), at Shouyang Dryland Farming Experimental Station in northern China during 2003-2008. The experiment was set-up using a split-plot design with 3 tillage methods as main treatments: conventional, reduced (till with crop residue incoperated in fall but no-till in spring), and no-till. Sub-treatments were 3 NP fertilizer rates: 105-46, 179-78 and 210-92 kg N and P ha. -1 Maize grain yields were greatly influenced by the amount of growing season rainfall, and by soil water contents at sowing. Mean grain yields over the 6-year period in response to tillage treatments were 5604, 5347 and 5185 kg ha, under reduced, no-till and conventional tillage, respectively. Mean WUE was 13.7, 13.6 and 12.6 kg ha mm under reduced, no-till, and conventional tillage, respectively. Mean soil water contents at sowing and at harvest were significantly influenced by tillage treatments. At harvest time, the no-till treatment had ~8-12% more water in the soil than the conventional and reduced tillage treatments. Under conventional tillage, grain yields increased with NP fertilizer application rates. However, under reduced tillage, grain yields were highest with lowest NP fertilizer application rate. In conclusion, grain yields and WUE were highest under reduced tillage at modest NP fertilizer application rates of 105 kg N and 46 kg P per ha. No-till increased soil water storage by 8-12% and improved WUE compared to conventional tillage

The 'Brazilian Test' as an indicator of workability for paddy soils in Vietnam

Farmers in Mekong delta prefer to till their soil in dry conditions when possible. They claim that crops establish and yield better when the field have been ploughed when dry compared to the wet preparation by puddling. Experiments were carried out to investigate the optimum workabilty range for the soils (heavy clay soils without any sand) in the area. A simple laboratory test procedure to serve as an alternative to field testing was developed. The test assesses the behaviour of soil under compressive forces. Soil aggregates from 5 different soils in the area were compressed into small discs at various mosture content levels and aggregate size classes. After drying, the tensile strength of the discs was determined using the “Brazilian test”. It was found that the strength of the discs was strongly dependent on moisture content at compaction, aggregate size and compressive force, but also the organic matter content of the soils played an important role. The Brazilian test provided useful information with respect to soil behaviour under tillage, in addition to the field tests

Soil quality assessment of rice production systems in South of Brazil

Soil quality, as a measure of the soil capacity to function, can be quantified by indicators based on physical, chemical and biological properties. Maintaining soil quality at a desirable level in the rice cropping system is a very complex issue due to the nature of the production systems used. In the state of Rio Grande do Sul, Brazil, rice production is one of the most important agricultural activities in the region. The study presented here was conducted with the following objectives: (i) to identify soil quality factors present from a set of soil indicators, (ii) to identify which selected indicators within these factors could discriminate between management systems or soil classes, (iii) to establish a minimum data set (MDS). Soil quality assessment was based on multivariate statistical analysis using the SPSS program. For this study, 29 soil biological, chemical and physical indicators were evaluated to characterize aspects of regional soil quality. Data were collected from rice fields located in the Camaquã region of Rio Grande do Sul that were under the three main soil management systems for rice. Different factors were found as the most important to discriminate either management systems or soil classes. The most powerful soil attributes retained into MDS for distinguishing differences in soil quality of rice production under different management systems and soil classes were copper, potassium, earthworm number, microbial quotient, manganese, organic matter, magnesium, iron, water stable aggregates, soil respiration, mineralizable N

Crop residue, manure and fertilizer in dryland maize under reduced tillage in northern China: I grain yields and nutrient use efficiencies

The rapidly increasing population and associated quest for food and feed in China has led to increased soil cultivation and nitrogen (N) fertilizer use, and as a consequence to increased wind erosion and unbalanced crop nutrition. In the study presented here, we explored the long-term effects of various combinations of maize stover, cattle manure and nitrogen (N) and phosphorus (P) fertilizer applications on maize (Zea mays L.) yield and nutrient and water use efficiencies under reduced tillage practices. In a companion paper, we present the effects on nutrient balances and soil fertility characteristics. The ongoing factorial field trial was conducted at Shouyang Dryland Farming Experimental Station in northern China from 1993 onwards. The incomplete, determinant-optimal design comprised 12 treatments, including a control treatment, in duplicate. Grain yields and N, P, and potassium (K) uptakes and N, P and K use efficiencies were greatly influenced by the amount of rain during the growing season (GSR), and by soil water at sowing (SWS). There were highly significant interactions between GSR and added stover and manure, expressed in complex annual variations in grain yield and N, P and K use efficiencies. Annual mean grain yields ranged from 3,000 kg ha¿1 to 10,000 kg ha¿1 and treatment mean yields from 4,500 kg ha¿1 to 7,000 kg ha¿1. Balanced combination of stover (3,000¿6,000 kg), manure (1,500¿6,000 kg) and N fertilizer (105 kg) gave the highest yield. Stover and manure were important for supplying K, but the effects differed greatly between years. Overall mean N recovery efficiency (NRE) ranged from 28% to 54%, depending on N source. NRE in wet years ranged from 50% to 90%. In conclusion, balanced combinations of stover, manure and NP fertilizer gave the highest yield and NRE. Reduced tillage with adding stover and manure in autumn prior to ploughing is effective in minimizing labor requirement and wind erosion. The potentials of split applications of N fertilizer, targeted to the need of the growing crop (response farming), should be explored to further increase the N use efficiency

Vee(n)houderij : rendabel mobiel melken in het Westelijk veenweidegebied

Over de problematiek van de melkveehouderij in het veengebied. Mobiele melkstal, mobiel melken in de regio Woerden - Bodegrave