• Authors:
    • Humphreys, E.
    • Yadvinder-Singh
    • Eberbach, P. L.
    • Katupitiya, A.
    • Kukal, S. S.
    • Balwinder-Singh
  • Source: Field Crops Research
  • Volume: 121
  • Issue: 2
  • Year: 2011
  • Summary: Intensive cultivation of rice and wheat in north-west India has resulted in air pollution from rice straw burning, soil degradation and declining groundwater resources. The retention of rice residues as a surface mulch could be beneficial for moisture conservation and yield, and for hence water productivity, in addition to reducing air pollution and loss of soil organic matter. Two field experiments were conducted in Punjab, India, to study the effects of rice straw mulch and irrigation scheduling on wheat growth, yield, water use and water productivity during 2006-2008. Mulching increased soil water content and this led to significant improvement in crop growth and yield determining attributes where water was limiting, but this only resulted in significant grain yield increase in two instances. There was no effect of irrigation treatment in the first year because of well-distributed rains. In the second year, yield decreased with decrease and delay in the number of irrigations between crown root initiation and grain filling. With soil matric potential (SMP)-based irrigation scheduling, the irrigation amount was reduced by 75 mm each year with mulch in comparison with no mulch, while maintaining grain yield. Total crop water use (ET) was not significantly affected by mulch in either year, but was significantly affected by irrigation treatment in the second year. Mulch had a positive or neutral effect on grain water productivity with respect to ET (WP ET) and irrigation (WP I ). Maximum WP I occurred in the treatment which received the least irrigation, but this was also the lowest yielding treatment. The current irrigation scheduling guidelines based on cumulative pan evaporation (CPE) resulted in sub-optimal irrigation (loss of yield) in one of the two years, and higher irrigation input and lower WP I of the mulched treatment in comparison with SMP-based irrigation scheduling. The results from this and other studies suggest that farmers in Punjab greatly over-irrigate wheat. Further field and modelling studies are needed to extrapolate the findings to a wider range of seasonal and site conditions, and to develop simple tools and guidelines to assist farmers to better schedule irrigation to wheat.
  • Authors:
    • Schwartz, R. C.
    • MacDonald, J. C.
    • Tolk, J. A.
    • Baumhardt, R. L.
  • Source: Agronomy Journal
  • Volume: 103
  • Issue: 3
  • Year: 2011
  • Summary: Cattle (Bos taurus) grazing intensifies production of the dryland wheat (Triticum aestivum L.)-sorghum [Sorghum bicolor (L.) Moench]-fallow (WSF) rotation in the U. S. Southern High Plains. Stubble-mulch (SM) tillage controls weeds and counteracts soil compaction. No-till (NT) increases soil water at planting and dryland crop yields, but added grazing effects are unknown. Our objectives were to quantify dryland winter wheat and sorghum yield responses to grazing and tillage practices. At the USDA-ARS Conservation and Production Research Laboratory, Bushland, TX, we established all WSF rotation phases in triplicate ungrazed and grazed paddocks beginning 1999 on a Pullman clay loam (fine, mixed, superactive, thermic Torrertic Paleustoll) using SM tillage. During spring 2004, NT or SM tillage were superimposed within grazing main plots. Cattle gain, soil water aft er fallow, and crop yield were compared during 2005 to 2009 using a split-plot randomized complete block design. Cattle, stocked at 1.8 Mg ha(-1), grazed sorghum stover and growing wheat an average of 29 d for a mean gain of 147 kg ha(-1). Soil water at planting was unaffected by grazing, but increased from 14 to 28 mm with NT. Although grazing seldom reduced yield of wheat or sorghum, NT in ungrazed plots increased crop yields sufficiently (0.96-2.6 Mg ha(-1)) in 2008 and 2009 to off set any value added by grazing. We conclude that cumulative grazing effects in NT plots reduced soil water storage and depressed yield. We recommend post-wheat-harvest SM tillage to disrupt soil compaction and restore grazed soil productivity.
  • Authors:
    • Robertson,G. P.
    • Hamilton,S. K.
    • Jasrotia,P.
    • Bhardwaj,A. K.
  • Source: Agriculture, Ecosystems & Environment
  • Volume: 140
  • Issue: 3-4
  • Year: 2011
  • Summary: Intensively cropped agricultural production systems should be managed to improve soil quality and ecological processes and ultimately strengthen system capacity for sustained biological productivity. We examined the long-term changes (>20 years) in soil quality and productivity with incorporation of ecological management principles in a set of intensively managed row crop systems of the upper Midwest, USA. Replicated experimental treatments include corn (maize)-soybean-wheat cropping systems under four different management regimes: (a) conventional tillage and fertilizer/chemical inputs ( Conventional), (b) no tillage with conventional fertilizer/chemical inputs ( No-till), (c) conventional tillage with 30% of conventional fertilizer/chemical inputs and a leguminous cover crop ( Reduced Input), and (d) conventional tillage with no fertilizer/chemical input and a leguminous cover crop ( Organic). Effects of these treatments on soils were compared by developing a soil quality index (SQI) from 19 selected soil health indicators. An old field community maintained in early succession provided a benchmark for comparison. Reduction in tillage or fertilizer ( No-till, Reduced Input and Organic) resulted in increased SQI and improved crop production. The No-till (SQI=1.02) and Reduced Input (SQI=1.01) systems outperformed Conventional management (SQI=0.92) in nitrogen availability and use efficiency, soil stability and structure improvement, and microbial nitrogen processing. Improvements in soil quality corresponded with increased primary production and crop yield in these systems, illustrating the value of an ecologically defined SQI for assessing the long-term effects of fertility and tillage management regimes in agricultural production systems.
  • Authors:
    • Rizzi, N. E.
    • Fey, E.
    • Lana, M. do C.
    • Bertol, O. J.
  • Source: Ciência Rural
  • Volume: 41
  • Issue: 11
  • Year: 2011
  • Summary: The no-tillage system, has contributed to improvements in agricultural soils, among them the like increases in nutrient concentrations of mineral elements in soil. However, it has been found that this increase concentration occurs mainly in the first few centimeters of the superficial top layer and so risks of nutrient losses by runoff, and associated of the soil, which concurs for losses of mineral elements through of runoff, with economic and environmental damages, are high. This study evaluated the total concentration, in runoff, of mineral elements potassium (K), calcium (Ca), magnesium (Mg) and copper (Cu) in total form and the soluble and particulate concentration form of K, in runoff caused to simulated rainfall of different intensitiesy applied over soil under no-till system and submitted to simulated after application of organic or mineral fertilizers in no-till soil. The fertilizers did not affect the concentration of mineral elements studied nutrients in runoff, except in condition of more high intense rainfall and soil under after organic manure application, which promoted runoff with showed the higher highest concentration of soluble and total K. Independent Irrespective of the type of fertilizers utilized type, the rainfall of higher intensity resulted in higher concentrations of all the mineral elements and forms studied, either in total, soluble or particulate form, evidencing the economic and environmental benefices, risks and suggesting that with the adoption of practices for runoff contention of runoff practices must be adopted, even in tilled croplands areas managed under no-till system.
  • Authors:
    • Beres, B. L.
    • Carcamo, H. A.
    • Dosdall, L. M.
    • Yang, R. C.
    • Evenden, M. L.
    • Spaner, D. M.
  • Source: Agronomy Journal
  • Volume: 103
  • Issue: 6
  • Year: 2011
  • Summary: Most semiarid regions of the northern Great Plains are prone to wheat stem sawfly (Hymenoptera: Cephidae, Cephus cinctus Norton) attack. As an alternative to the wheat ( Triticum aestivum L.)-fallow system, our objective was to determine if continuous cropping infested wheat stubble would inhibit wheat stem sawfly (WSS) emergence. Adult sawfly emergence from undisturbed stubble was compared to stubble harrowed with heavy tine or rotary drum harrows before recropping. Adult emergence from a control of "no recropping" was compared to direct seeding infested stubble with (i) air drills configured with knife-type openers spaced 23 or 30 cm apart, (ii) an air drill configured with high disturbance shovel-type sweep openers, and (iii) a low disturbance air drill equipped with disc openers. Pre-seed heavy tine harrowing reduced adult sawfly emergence but usually required a high tension setting. No-till planting into infested spring wheat stubble also lowered WSS emergence compared to leaving the field fallow. A system of heavy tine harrows and an air drill equipped with knife openers spaced 30 cm apart reduced WSS adult emergence in spring by 50 to 70%. Grain yield was optimized in spring wheat with air drills equipped with narrow knife openers; in winter wheat optimal yield was obtained with the low disturbance disc drill configurations. Our results indicate incremental benefits from continuous cropping rather than fallowing fields infested with WSS, which is a sustainable alternative to conventional tillage. A systems approach is recommended that integrates these practices with diversified nonhost crop phases and resistant cultivars.
  • Authors:
    • Garcia, F.
    • Garcia, A.
    • Ernst, O.
    • Cano, J.
    • Bordoli, M.
    • Beux, L.
    • Bautes, C.
    • Barbazan, M.
    • Quincke, A.
  • Source: Agrociencia (Montevideo)
  • Volume: 15
  • Issue: 2
  • Year: 2011
  • Summary: The objectives of this study were to summarize the recent information generated in the country related to the potassium fertilization and find a tentative critical level of Potassium (K) in soil for various crops in Uruguay, using the most widely used K soil test. The data come from 50 K-response experiments in barley, wheat, corn, soybeans, sorghum, and sunflower, conducted by different working groups from 2004 to 2010, in soils with different texture and exchangeable K levels. The fertilizer rates ranged from 0 to 240 kg/ha of K 2O and in all cases the source of K was broadcasted KCl at planting date. Potassium fertilizer increased crop yield in 15 of 50 sites (Pr
  • Authors:
    • Ferrari, S.
    • Picoli, P.
    • Lazarini, E.
    • Barbosa, C.
  • Source: Cientifica (Jaboticabal)
  • Volume: 39
  • Issue: 1/2
  • Year: 2011
  • Summary: The objective of this study was to evaluate the straw effect of four cover crops [grain sorghum ( Sorghum bicolor L. Moench), sun hemp ( Crotalaria juncea L.), pearl millet ( Penisetum americanum L.), and brachiaria ( Brachiaria brizantha cv. Marandu)] sown at two different times and a fallow area and its effects on soybean cultivated in succession in a no tillage system. The study was carried out from march/08 to april/09 in the experimental farm of the College of Engineering, a unit of the Universidade Estadual Paulista (UNESP), located in Selviria, a county of the state of Mato Grosso do Sul, (51degrees22′W and 20degrees22′S, with 335 m altitude), Brazil, in an Oxisol. The treatments consisted in the sowing of the four cover crops on March 27 and April 23 of 2008 and in the use of a fallow area. The experiment was set in the field according to a randomized complete block design with eight repetitions. Forage crops (sunhemp and B. brizantha) sown in two seasons do not change the soybean yield. Soybean yield on sorghum and millet sown in March was higher than that observed for the same crops sown in April. The grasses used are shown as a viable option for the production of dry matter for soybean sown in March.
  • Authors:
    • Fiorin, J.
    • Nicoloso, R.
    • Tornquist, C.
    • Amado, T.
    • Campos, B.
  • Source: Revista Brasileira de Ciencia do Solo
  • Volume: 35
  • Issue: 3
  • Year: 2011
  • Summary: Soil C-CO 2 emissions are sensitive indicators of management system impacts on soil organic matter (SOM). The main soil C-CO 2 sources at the soil-plant interface are the decomposition of crop residues, SOM turnover, and respiration of roots and soil biota. The objectives of this study were to evaluate the impacts of tillage and cropping systems on long-term soil C-CO 2 emissions and their relationship with carbon (C) mineralization of crop residues. A long-term experiment was conducted in a Red Oxisol in Cruz Alta, RS, Brazil, with subtropical climate Cfa (Koppen classification), mean annual precipitation of 1,774 mm and mean annual temperature of 19.2degreesC. Treatments consisted of two tillage systems: (a) conventional tillage (CT) and (b) no tillage (NT) in combination with three cropping systems: (a) R0 - monoculture system (soybean/wheat), (b) R1 - winter crop rotation (soybean/wheat/soybean/black oat), and (c) R2 - intensive crop rotation (soybean/black oat/soybean/black oat+common vetch/maize/oilseed radish/wheat). The soil C-CO 2 efflux was measured every 14 days for two years (48 measurements), by trapping the CO 2 in an alkaline solution. The soil gravimetric moisture in the 0-0.05 m layer was determined concomitantly with the C-CO 2 efflux measurements. The crop residue C mineralization was evaluated with the mesh-bag method, with sampling 14, 28, 56, 84, 112, and 140 days after the beginning of the evaluation period for C measurements. Four C conservation indexes were used to assess the relation between C-CO 2 efflux and soil C stock and its compartments. The crop residue C mineralization fit an exponential model in time. For black oat, wheat and maize residues, C mineralization was higher in CT than NT, while for soybean it was similar. Soil moisture was higher in NT than CT, mainly in the second year of evaluation. There was no difference in tillage systems for annual average C-CO 2 emissions, but in some individual evaluations, differences between tillage systems were noticed for C-CO 2 evolution. Soil C-CO 2 effluxes followed a bi-modal pattern, with peaks in October/November and February/March. The highest emission was recorded in the summer and the lowest in the winter. The C-CO 2 effluxes were weakly correlated to air temperature and not correlated to soil moisture. Based on the soil C conservation indexes investigated, NT associated to intensive crop rotation was more C conserving than CT with monoculture.
  • Authors:
    • Hontoria, C.
    • Lammerding, D.
    • Tenorio, J.
    • Walter, I.
  • Source: Agronomy Journal
  • Volume: 103
  • Issue: 2
  • Year: 2011
  • Summary: It is widely accepted that conservation tillage management affords benefits to soil properties and reduces production costs; therefore these practices could be attractive to farmers from semiarid regions. The objective of this study was to assess the long-term effects of different tillage practices under semiarid conditions on macroaggregate stability (water stable aggregates, WSA), soil organic carbon (SOC), and particulate organic carbon (C-POM) content of an Alfisol from Spain. The experimental design involved a split plot and four randomized blocks in which tillage was the main factor and crop rotation (fallow-wheat-pea-barley) the secondary factor. Three tillage systems were compared: no tillage (NT), minimum tillage (MT), and conventional tillage (CT). Soil samples were collected on November 2006 and October 2007. In November 2006 no significant differences in WSA were found among the tillage treatments. In October 2007, however, the mean WSA in the upper soil layer for the NT was significantly higher, 24%, that in the CT. No significant differences were seen for the subsurface layer. Under NT, the SOC and C-POM values for the surface soil layer were significantly higher than those for the other treatments on both sampling dates. At the subsurface depth, no significant differences were seen in either of these variables. The SOC and C-POM values were more homogeneous throughout the soil profile in the plowed soil than in the NT for which the corresponding values were more stratified. The results show that NT will help improve soil structure and soil fertility, which is particularly relevant to semiarid conditions like the area studied.
  • Authors:
    • Zeng, Y.
    • Li, W.
    • Liang, H.
    • Nong, M.
    • Yang, W.
    • Liu, Y.
  • Source: Guizhou Agricultural Sciences
  • Issue: 11
  • Year: 2011
  • Summary: A non-tillage intercropping test of potato varieties of Qingshu series was conducted in mulberry garden in winter to seek a fine intercropping pattern and to screen the suitable potato varieties. The results showed that compared with potatoes of conventional non-tillage cultivation, growth traits of the five potato varieties of Qingshu series were better in different growth periods, such as plant height, stem diameter, leaf number, and the yield structure was improved. Potato weight and potato number per plant were increased by 21.14% and 16.32%, respectively. Potato production and the proportion of larger potatoes were raised by 5.92% and 11.94%, respectively. The yield of Qingshu 8 was the highest (37 070.37 kg/hm 2), 8.98% higher than CK. Therefore, mulberry intercropping potatoes was a new cultivation way to be generalized and applied in the production practice. Qingshu 8 was an ideal potato variety for non-tillage intercropping in mulberry garden.