Archives of Agronomy and Soil Science

Aparecido, Lucas Eduardo de Oliveira; Moraes, José Reinaldo da Silva Cabral de; Rolim, Glauco de Souza; Martorano, Lucieta Guerreiro; Meneses, Kamila Cunha de; Valeriano, Taynara Tuany Borges

doi: 10.1080/03650340.2019.1566715pmid: N/A

Sunflower is a species that is sensitive to local climate conditions. However, studies that use artificial neural networks (ANNs) to evaluate this influence and create tools such as agricultural zoning of climate risk (ZARC) have not been conducted for this species. Due to the importance of sunflower as a human food source and for biodiesel production, and also the necessity of conducting research to evaluate the suitability of this oleaginous species under different climatic conditions. Thus, we seek to construct a ZARC for sunflower in Brazil simulating sowing on different dates and using meteorological elements spatialized by ANNs. Climate data were used: air temperature (T), rainfall (P), relative air humidity (UR), solar radiation (MJ_m−2_d−1) and wind velocity (U2). Climatic regions considered suitable for the cultivation of sunflower had average annual values for T between 20 and 28°C, P between 500 and 1.500 mm per cycle, and soil water deficit (DEF) below 140 mm per cycle. A neural network is an efficient tool that can be used in spatialization of climate variables quickly and accurately. Sunflower sowing in the spring and summer are the ones that provide the largest suitable areas in southeastern Brazil, with 58.13 and 64.36% of suitable areas, respectively.

Bordoloi, Nirmali; Baruah, Kushal Kumar; Bhattacharyya, Pradip; Gupta, Prabhat Kumar

doi: 10.1080/03650340.2019.1566716pmid: N/A

Identification of the combination of tillage and N fertilization practices that reduce agricultural Nitrous oxide (N2O) emissions while maintaining productivity is strongly required in the Indian subcontinent. This study investigated the effects of tillage in combination with different levels of nitrogen fertilizer on N2O emissions from a rice paddy for two consecutive seasons (2013–2014 and 2014–2015). The experiment consisted of two tillage practices, i.e., conventional (CT) and reduced tillage (RT), and four levels of nitrogen fertilizer, i.e., 0 kg N ha–1 (F1), 45 kg N ha–1 (F2), 60 kg N ha–1 (F3) and 75 kg N ha–1 (F4). Both tillage and fertilizer rate significantly affected cumulative N2O emissions (p < 0.05). Fertilizer at 45 and 60 kg N ha–1 in RT resulted in higher N2O emissions over than did the CT. Compared with the recommended level of 60 kg N ha−1, a 25% reduction in the fertilizer to 45 kg N ha−1 in both CT and RT increased nitrogen use efficiency (NUE) and maintained grain yield, resulting in the lowest yield-scaled N2O-N emission. The application of 45 kg N ha−1 reduced the cumulative emission by 6.08% and 6% in CT and RT practices, respectively, without compromising productivity.

Matos, Christiano; Teixeira, Rafael; Silva, Ivo; Costa, Maurício; Silva, Antônio

doi: 10.1080/03650340.2019.1566717pmid: N/A

Certain plant combinations can stimulate the mineralization of soil organic matter (SOM), thereby changing the storage of soil organic carbon and affecting the physical and chemical soil properties. The aim of this study was to evaluate whether competition between weeds and maize can stimulate SOM decomposition. Eight treatments were performed: monoculture of maize and weeds (Amaranthus viridis, Bidens pilosa, and Ipomoea grandifolia), maize in competition with weeds, and non-cultivated soil. During cultivation, the rhizosphere priming effect (RPE) on SOM was estimated. Additionally, at 60 days after planting, soil samples were collected to measure the C contents of particulate (POM) and mineral-associated (MAOM) organic matter. From the 43rd day of cultivation onwards, the coexistence between maize and B. pilosa led to the highest RPE values, while maize vs. A. viridis showed negative RPE. Maize vs. A. viridis and maize vs. I. grandifolia caused increase in MAOM-C and decreases in POM-C. Ipomoea grandifolia monoculture and maize vs. B. pilosa led to the highest MAOM-C losses and reduced POM-C compared to the non-cultivated soils. Here it is demonstrated that competition between maize and B. pilosa increases SOM mineralization, while competition between maize and A. viridis or I. grandifolia retards this process.

Zheng, Lijian; Ma, Juanjuan; Sun, Xihuan; Guo, Xianghong; Li, Yongye; Ren, Rong; Cheng, Qiyun

doi: 10.1080/03650340.2019.1566718pmid: N/A

Ways of understanding and quantifying the effectiveness of new irrigation methods are required in order to more precisely evaluate them, including the effect of root growth on water storage pit irrigation (WSPI). In this study, the effective root growth zone (ERGZ) of 5-year-old apple trees under WSPI and traditional surface irrigation (CK) treatment was estimated using stable isotope technology during two seasons 2015 and 2016. The stable isotopes of water in stems and different soil depths were analyzed using four analysis methods (namely direct inference, the Romero-Saltos model, the IsoSource model and the coupled model). Results showed that the ERGZ depth under surface irrigation ranged from 10 cm to 60 cm, with the main contribution at 0–40 cm during the growth stage. Under water storage pit irrigation, the ERGZ depth for the apple tree was deeper and ranged from 20 cm to 100 cm, with the main contribution of ERGZ deepened to 20–100 cm after the earlier of shoot rapid-growing stage. The use of a water storage pit irrigation system on apple demonstrated improved root growth in the middle-depth soils, as compared to traditional surface irrigation.

Iqbal, Nadeem; Manalil, Sudheesh; Chauhan, Bhagirath S.; Adkins, Steve W.

doi: 10.1080/03650340.2019.1566720pmid: N/A

Cotton is an important cash crop grown on 2.5% of the world’s arable land in over 100 countries, and has a 31% share of the world’s fibre market. In Australia, cotton is also a leading crop and contributes around AUD $3 billion to the total agricultural production. Weeds are a major biotic constraint resulting in yield losses of up to 90% and revenue losses of around AUD $100 billion globally and $4 billion to Australian agriculture. Genetically-modified (GM) crops have refashioned the weed management with more dependency on glyphosate. Such overreliance has led to the evolution of 43 glyphosate-resistant (GR) weed populations globally, with 16 species reported from Australia. Such GR weeds along with volunteer glyphosate-tolerant (GT) plants are now decreasing the value of the GM crops and forcing growers to spend more time and effort, and investment in their management. Weed management strategies need to be diversified and integrated with non-chemical methods and alternative herbicides not only to achieve efficient control, but to reduce the rate of evolution of GR weeds. In future, research is needed to improve integrated weed management through development and use of competitive and multiple herbicide-tolerant (HT) crops, organic herbicides, bio-herbicides, RNAi technology and robotics.

Zaheer, Muhammad Saqlain; Raza, Muhammad Aown Sammar; Saleem, Muhammad Farrukh; Khan, Imran Haider; Ahmad, Salman; Iqbal, Rashid; Manevski, Kiril

doi: 10.1080/03650340.2019.1566954pmid: N/A

Plant growth-promoting rhizobacteria (PGPR) play an important role in improving crop growth but have not been studied sufficiently. A wire house experiment was conducted in Pakistan to determine the combined effect of inoculating wheat seeds with PGPR on the subsequent growth and yield of the wheat. The experiment included four treatments: T0 – no-inoculation (control), T1 – Azospirillum brasilense inoculation, T2 – Rhizobium pisi inoculation and T3 – co-inoculation with A. brasilense and R. pisi. Development and growth attributes, as well as final yield of wheat, were studied. Co-inoculation of seeds with both strains increased significantly wheat grain yield, the number of grains per plant and 1000-grain weight by 36%, 11% and 17%, respectively, compared to non-inoculated control. While crop growth rate increased for, respectively, 5.5% and 33% at tillering and flag leaf stages, corresponding values for T3 were about 9% and 14% higher than values for sole inoculations in T1 and T2. Co-inoculation also significantly increased leaf epicuticular wax and relative water content as compared to the control treatment. Thus, inoculation of wheat seeds with A. brasilense and R. pisi and their combination is a promising method to improve growth, yield and quality of wheat.

Melgarejo, Pablo; Legua, Pilar; Pérez-Sarmiento, Francisco; Martínez-Font, Rafael; Martínez-Nicolás, Juan José; Giordani, Edgardo; Tozzi, Francesca; Hernández, Francisca

doi: 10.1080/03650340.2019.1569758pmid: N/A

The maritime ports and terminals periodically carry out dredging activities. This operation is necessary in order to avoid the excessive accumulation of sediments in the areas of maneuvering and berthing of ships. Thus, the objective of this study was to investigate the effect that dredged remediated sediments have on the quality and bioactive components of pomegranate (Punica granatum L.) cultivar ‘Purple Queen’. Pomegranate trees were grown on three substrate-based treatments: Peat 100% (Pt as a control), dredged remediated sediments 100% (DRS), and a 50% mixture of each (Pt-DRS). Pomegranate fruits and two types of juices (juice of arils and juice of arils plus carpellary membranes) were characterized. The results showed that the use of dredged remediated sediments 100% (DRS) negatively affected yield, numbers of fruit per tree, and fruit weight average of pomegranate fruits. However, neither fruit quality nor composition of pomegranates grown on this substrate and mixture were affected. The tested media showed suitable horticultural properties for pomegranate cultivation, at which the Pt and Pt-DRS had better plant responses than the DRS one.

Filipek-Mazur, Barbara; Tabak, Monika; Koncewicz-Baran, Małgorzata; Bobowiec, Aneta

doi: 10.1080/03650340.2019.1571268pmid: N/A

Because of low content of available iron (Fe) in soils and its poor mobility in plants, iron fertilization is necessary. Different forms of iron (mineral salts, chelates, nanomaterials) and fertilization strategies (soil and foliar application of solid or liquid fertilizers) are used. The effect of solid mineral fertilizers (A: a mixture of ammonium nitrate and dolomite; B: a mixture of ammonium nitrate and sulfate) enriched with iron sulfate was assessed during a three-year pot experiment. Iron addition did not change the yield of spring rape (first year) or maize (second and third year) significantly, and the effect on iron content in the plants was ambiguous. Fertilizer B with iron had the greatest yield-forming effect, increasing the yield of aboveground parts by 355–874%, and of roots by 211–692% in particular years. All fertilizers (especially containing sulfur) acidified the soil. After the experiment, pH of the soil fertilized with sulfur was 4.1, and of the unfertilized soil – 5.2. Iron addition increased the content of mobile and exchangeable iron in the soil by 12–110% and 2–58%, respectively, but not the content of the fraction bound to MnOx. Combination of sulfur and iron fertilization has a potential to improve soil abundance and plant yield.

Li, Shan; Xiao, Yi; Li, Qiquan; Wang, Changquan; Li, Bing; Yuan, Dagang; Tao, Qi; Gao, Xuesong; Zhao, Bin; Li, Yiding

doi: 10.1080/03650340.2019.1571269pmid: N/A

The vertical dynamics of paddy soil organic carbon (SOC) play an important role in soil quality and carbon cycling. In this study, we used an exponential decay function to estimate the vertical dynamics of SOC content and determined its influencing factors in a typical paddy soil area of the Chengdu Plain from the 1980s to the 2010s. Our results show an overall increase in SOC stocks at 0–100 cm from 11.8 Tg in the 1980s to 13.7 Tg in the 2010s. SOC content increased at depths of 0–40 cm and declined at depths of 40–100 cm over the past three decades. The exponential decay function parameters C0 and k significantly increased by 31.4% and 18.2% respectively, which suggests the vertical pattern of SOC distribution changed. The increase in nugget effects of C0 and k and the decrease in the relative contributions of the parent material, subgroup and distance-to-river indicate that extrinsic factors played increasing roles in the vertical variation of SOC content. Our study concludes that rice planting has led to vertical variations of SOC content and decreased the effects of intrinsic factors on the vertical variation of SOC content of Chengdu Plain paddy soils over the past three decades.

Basak, B. B.

doi: 10.1080/03650340.2019.1571681pmid: N/A

The chemical reactivity of Indian rock phosphates (RPs) was measured by five chemical extraction methods (i.e. water, neutral ammonium citrate (NCA), 2% citric acid (CA), 2% formic acid (FA) and absolute citrate solubility (ACS)). These measurements were assessed by agronomic response data obtained by growing ryegrass and palmarosa in two highly weathered acidic soils under pot culture experiment. The phosphorus (P) solubility value of RP measured by different methods followed the order: ACS > 2% CA > 2% FA > NAC > water. Considering triple superphosphate (TSP) as a standard reference P fertilizer, the agronomic response of RPs followed the order Udaipur RP > Jhabua RP ≥ Purulia RP > Mussorie RP. Methods based on citrate solubility (i.e. NAC, 2% CA and ACS) were significantly and positively correlated with agronomic response irrespective of the plant species and soil types. The best correlation value obtained with NCA indicated that P solubility in NAC solution may offer better prediction of agronomic effectiveness of RP in terms of biomass yield, relative agronomic efficiency (RAE) and P recovery efficiency. So, the present investigation will help to predict the agronomic effectiveness of low-grade RP based on chemical methods.