Soil physical changes and maize growth in a structurally fragile tropical soil due to mulching and duration between irrigation intervals

Under tropical meteorological conditions, the volume of soil explored by plant roots is crucial for crop growth as it allows increased water and nutrient use efficiency. We hypothesized that, under different irrigation intervals, leguminous mulch can extend the duration between irrigation events but maintain crop performance, because decreased evaporative fluxes also reduce constraints to root exploration imposed by mechanical stress. We evaluated the combined effects of leguminous mulch and irrigation intervals on soil physical properties to determine whether the growth and productivity of maize were modified in a structurally fragile tropical soil. The experiment involved the following treatments: 4‐day irrigation intervals with soil mulched (4C) or bare (4S), 6‐day irrigation intervals with soil mulched (6C) or bare (6S), 8‐day irrigation intervals with soil mulched (8C) or bare (8S) and 10‐day irrigation intervals with soil mulched (10C) or bare (10S). Mulch decreased soil penetration resistance and increased to 4 days the favourable time for root development in drying soil. Relative to bare soil, mulch with a 6‐day irrigation interval almost doubled nitrogen uptake post‐tasselling, which decreased nitrogen remobilization and increased the crop growth rate during this stage. These conditions had a positive effect on the transpiration rate and stomatal conductance as well as on the growth and yield of maize. A 6‐day irrigation interval with mulch compared to 4 days with bare soil resulted in similar conditions for root development, but greater uptake of nitrogen (102.73–78.70 kg/ha) and better yield (6.2–5.3 t/ha), which means greater efficiency in nitrogen and water use.     

Film fully-mulched ridge-furrow cropping affects soil biochemical properties and maize nutrient uptake in a rainfed semi-arid environment

Abstract

This study evaluated the effects of plastic mulched ridge-furrow cropping on soil biochemical properties and maize (Zea mays L.) nutrient uptake in a semi-arid environment. Three treatments were evaluated from 2008 to 2010: no mulch (narrow ridges with crop seeded next to ridges), half mulch (as per no mulch, except narrow ridges were mulched), and full mulch (alternate narrow and wide ridges, all mulched with maize seeded in furrows). Compared to the no mulch treatment, full mulch increased maize grain yield by 50% in 2008 and 25% in 2010, but reduced yield by 21% in 2009 after low precipitation in early growth. Half mulch had a similar grain yield to no mulch in the three cropping years, suggesting half mulch is not an effective pattern for maize cropping in the area. Mulch treatments increased aboveground nitrogen (N) uptake by 21?34% and phosphorus (P) uptake by 21?42% in 2008, and by 16?32% and 14?29%, respectively, in 2010; but in 2009 mulching did not affect N uptake and decreased P uptake. Soil microbial biomass and activities of urease, β-glucosidase and phosphatase at the 0?15 cm depth were generally higher during vegetative growth but lower during reproductive growth under mulch treatments than no mulch. Mulching treatments increased carbon (C) loss of buried maize residues (marginally by 5?9%), and decreased light soil organic C (15?27%) and carbohydrate C (12?23%) concentrations and mineralizable C and N (8?36%) at harvest in the 0?20 cm depth compared with no mulch, indicating that mulching promotes mineralization and nutrient release in soil during cropping seasons. As a result of these biological changes, mineral N concentration under mulch was markedly increased after sowing in upper soil layers compared with no mulch. Therefore, our results suggest that mulched cropping stimulated soil microbial activity and N availability, and thus contributed to increasing maize grain yield and nutrient uptake compared with no mulch.     

Mulch effect on successive crop yields and soil carbon in Tonga

Intensification of crop production in Tonga has resulted in a move to mechanical soil preparation, often with a rotary hoe, and a consequent loss in both chemical physical fertility. An experiment was conducted on a clay loam soil (Typic Argiudoll) on the Forestry Vaini Research Station, Tongatapu Island, Tonga, to investigate the effect of a once‐off application of mulch on yield and quality of watermelon, maize and capsicum grown in rotation over a 1‐yr period. The treatments applied were a nonmulched control, transparent plastic and 200‐mm‐thick applications of locally available coconut sawdust, guinea grass and mature coconut fronds. The fresh fruit yield of watermelon in all the mulch treatments was 7.3–18.1% higher than in the nonmulched control. There was no significant effect of thick vegetative mulch on maize grain dry matter yield; however, the maize yield was significantly lower in the transparent plastic mulch than in the other treatments. The capsicum marketable fruit yield in the following crop was increased by 49–73% in all the vegetative mulch treatments compared to the non‐mulched control. The higher crop yields with the vegetative mulch were attributed to the measured lower soil temperatures and higher soil moisture in these treatments. There was no effect of mulch on soil total N (TN), but soil total C (TC), soil labile C (LC) and the carbon management index (CMI) were increased.     

降雨和前期含水量对大别山区不同作物坡面产流产沙的影响

基于霍山县水土保持试验站3个径流小区（茶叶、桑树、红芋）2016—2017年逐日连续观测数据，定量研究土壤含水量与天然降雨条件下产流产沙规律与动态变化特征。结果表明：（1）4—7月为产流高峰期，该时期各小区产流量占年产流量的76%（桑树），57%（茶叶），70%（红芋）。3种作物对产流产沙的抑制效果为茶树地 > 桑树地 > 红芋地。（2）各作物年内土壤含水量变化趋势相似，全年变化呈"W"形。其中表层土壤平均含水量排序为茶树地 > 桑树地 > 红芋地，与作物抑制产流产沙效果排序一致。秋季土壤水分稳定性最强，夏季最弱。全年以桑树为例的乔木对土壤水分稳定效果最好。（3）降雨参数与土壤含水量之间灰色关联度大小为历时 > 平均雨强 > I₃₀ > I₆₀ > 雨量。作物小区内产流量贡献度最大变量为降雨侵蚀力，而就产沙量而言，茶叶地与红芋地的产沙量贡献度最大变量为I₃₀，对桑树地产沙贡献度最大变量为降雨量。     

Zum Einfluß von obstbaulichen Bodenpflegemaßnahmen auf Lumbriciden,insbesondere Lumbricus terrestris L .

Influence of orchard soil management on lumbricids, especially Lumbricus terrestris L. In a long-term soil management experiment (apple orchard treated with cultivation methods such as grass mulch, grass harvest, straw mulch, clean cultivation) 6 plots were selected in order to study the abundance and biomass of earthworm populations. The following results were obtained: In all treatments with the exception of straw mulch L. terrestris represented the majority (60.5% on average) of the lumbricid population. Their share in the biomass amounted to 93.3%. The earthworm biomass was the highest in grass mulch; a close correlation was observed between the litter production (grass and leaves) and the biomass of L. terrestris. Added farm yard-manure on plots with grass mulch had no additional positive effect on earthworms. Although a higher earthworm biomass was found under grass mulch in comparison with straw mulch, the species diversity was higher in the latter. Clean cultivation had a highly detrimental effect on all earthworms, especially on the horizontally burrowing species. The annual nitrogen turnover by L. terrestris in mulched orchards was estimated to approx. 50 kg N/ha.     

西辽河平原覆膜和浅埋对滴灌玉米生长的影响

为对比研究覆膜和浅埋对滴灌玉米生长的影响,以西辽河平原为研究区,设置膜下滴灌与浅埋滴灌2种灌溉方式和高、中、低3种灌溉水平,对滴灌玉米生长指标、根系分布、耗水量及产量等进行分析,寻求适宜试验区玉米高效节水灌溉模式。结果表明:(1)平均叶面积指数膜下滴灌较浅埋滴灌处理高13%～20%。膜下滴灌根系在30 cm土层内分布均匀,浅埋滴灌根系分布较膜下滴灌深10 cm。(2)膜下滴灌总耗水量较浅埋滴灌低9%,节水效果明显。(3)平水偏枯年膜下滴灌处理产量高于浅埋滴灌7%～15%,平水偏丰年膜下滴灌处理的产量低于浅埋滴灌处理6%～19%(p0.05)。(4)中水处理产量高,水分生产率最大,为最佳灌水处理。(5)对不同研究区通过多年平均降雨量和当年降雨预报推算生育期降雨量,对于268.32 mm的地方推荐使用膜下滴灌更佳,灌溉定额为186.1 mm,灌水7次。降雨量268.32 mm的地方推荐使用浅埋滴灌更佳,灌溉定额为228.0 mm,灌水8次。研究结果可为试验区及类似地区玉米高效灌溉生产提供理论依据。     

Utilization of MSW Compost In Nursery Stock Production

This three year study was conducted to evaluate the suitability of municipal solid waste (MSW) compost as a soil amendment or a mulch to suppress weeds in the production of field grown nursery stock. In the soil amendment experiment, compost was applied at the rates of 0, 56, and 112 t/ha and incorporated into the soil prior to planting. In the mulch/weed control experiment, 224 t/ha of compost was applied to one set of plots as a mulch after planting and compared to plots treated with herbicide and untreated controls. Each plot in both experiments contained four rows with one each of red maple (Acer rubrum L.), sugar maple (Acer saccharum Marsh.), white pine (Pinus strobus L.), and pin oak (Quercus palustris Muenchh.). Mortality and weed counts were determined during the first growing season. Annual measurements of crown height, crown width, and caliper (at the 1 foot level) were made the following three winters. Two inches of compost mulch (224 t/ha) provided adequate weed control only in the first year. Mowing suppressed the weeds that invaded the plots beyond the first year. For maples, first year mortality in plots mulched with 224 t/ha compost or amended with 112 t/ha compost was significantly less than unamended controls. In subsequent years, the mulched maples grew more than trees in the unamended controls. In the plots amended with 56 or 112 t/ha compost, sugar maples had increased height, canopy, and caliper growth compared to the unamended controls. The hearty pin oak saplings survived transplanting and there was a significant increase in caliper growth in plots amended with 112 t/ha (1 inch) of compost. Mortality of white pine increased when mulched with 224 t/ha compost. Increased mortality was most likely due to high concentrations of ammonium and soluble salts in the immature compost. Beyond the first year, there were no negative impacts on the growth of white pine from any of the compost treatments.     

Effects of ridge‐furrow and plastic mulching planting patterns on microflora and potato tuber yield in continuous cropping soil

Planting patterns have distinctive effects on the soil micro‐ecological environment and soil quality. To explore the effects of film mulch ridge‐furrow (FMRF) cropping on soil microbial properties and potato yield, a study was conducted in 2013 and 2014 in a continuously cropped field under nonfilm‐mulched flat plot (CK), half‐mulched flat plot (T1), fully mulched ridge cropping (T2), fully mulched furrow cropping (T3), half‐mulched ridge cropping (T4) and half‐mulched furrow cropping (T5) planting patterns. Our results indicate that T3 increased the average bacteria/fungi (B/F) ratio by 253% compared to CK. On average, half‐mulched ridge cropping increased the bacteria population and aerobic Azotobacter by 9 and 19%, respectively, compared with CK. On average, T3 had the greatest inhibitory effect on fungi populations. Half‐mulched furrow cropping had the most anaerobic Azotobacter and nitrifying bacteria. The study showed that FMRF increased soil bacteria, especially Azotobacter but reduced fungi and actinomycetes. Treatment T2 gave the greatest potato yield, followed by T4, whereas the greatest biomass yield was recorded in T4. Full‐mulch furrow cropping methods produced the greatest nutrient use efficiency. The findings of this study enhance our understanding of soil microbe and plant responses to plastic mulch and planting patterns under semi‐arid conditions.     

Crop and water productivity,profitability and energy consumption pattern of a maize-based crop sequence in the North Eastern Himalayan Region,India

Mono-cropping is the most common farming practice followed in the North Eastern Hilly Region (NEHR) of India and farmers leave the land fallow after harvesting the main crop. The identification of suitable sequential crops is essential to increase the cropping intensity, land-use efficiency and overall productivity of the land. Therefore, a study was carried out during 2008–09, 2009–10 and 2010–11 on maize (rainy season) followed by table pea, mustard, French bean and groundnut (post rainy season). Sequence crops were imposed with paddy straw mulch at 5.0 t ha^?1 and without mulch. The availability of water and moisture retention was higher (p < 0.05) on mulched plots, yield was also higher. However, recorded soil temperature was higher on mulched plots at 08.00 hours and lower at 12.00 and 16.00 hours compared with the no-mulch plots. Recorded maize equivalent yield, production efficiency, economics and total energy use and output (MJ ha^?1) were higher for maize–French bean.     

Colored plastic mulches affect soil temperature and tuber production of potato

Abstract

The main crops on which plastic mulch is widely used in Mexico include tomato, bell pepper, eggplant, melons, watermelons, and strawberry; however, very little research has been performed on potato. One of the main benefits associated with plastic mulching is the modification of the microclimate around the plant. To obtain a positive microclimate modification studies are required to understand how plastic mulch affects growth and yield of a given species. Previous field research assessing the response to colored plastic mulching in potato shows no consistent results on yield, maybe because it has been performed under different geographical latitudes. Potato in Mexico is conventionally cultivated on bare soil combined with various irrigation systems. The objective of the present study was to examine the effect of colored plastic mulches on soil temperature, growth, yield and photosynthetic response of potato plants. The experiment was conducted in Northeast Mexico and the treatments included were: black plastic mulch (BPM); white-on-black plastic mulch (W/B), silver-on-black (SPM), aluminum-on-black plastic mulch (APM) and a control that consisted of bare soil cultivated plants. Treatments were arranged in a randomized complete block design with four replications. Results suggest that average daily mean soil temperature was linearly and negatively correlated with total yield and yield of first-quality tubers. Total yield and yield of first-quality tubers of plants mulched with W/B, SPM and APM was significantly higher (p≤0.05) than those of control plants. Leaf area and shoot dry weight were increased when soil temperatures were higher due to the effect of radiation transmission to the soil, however, this decrease was associated with a decrease in tuber production. The results of our study indicate that plants grown under BPM, which induced the highest soil temperature, showed marginal difference in yield compared with control plants, suggesting that colored plastic mulches have a positive effect on yield through decreased rise in soil temperature.     

Effects of vetiver grass (Vetiveria nigritana) strips, vetiver grass mulch and an organomineral fertilizer on soil, water and nutrient losses and maize (Zea mays, L) yields

Soil erosion remains a serious problem on most agricultural fields especially in the humid tropics. Experiments were conducted between 2003 and 2005 to test the efficiency and efficacy of using vetiver grass strip (VGS), vetiver grass mulch (VGM) and an agronomic practice of using an organomineral fertilizer (OMF) capable of improving soil structure and a control, as treatments, on soil and water conservation and improvement of maize yields. The treatments, in three replicates, were laid out in a randomized complete block design on 7% runoff plots on an Alfisol in the sub humid region of Southern Nigeria. Soil physical conditions were significantly best under VGM plots and least under VGS plots. Nevertheless, runoff and soil loss were generally in the increasing order of VGS, VGM and OMF. Although mean runoff and soil loss on VGS plots were 36.6% and 28% of the value of the control plot in 2003, when 2 tonnes/ha of vetiver grass mulch was applied to the control plot in 2004, these values were increased to 61.5% and 48.4%, respectively indicating a significant reduction of runoff and soil loss on the mulched plots. Vetiver grass mulch (VGM) at 6 tonnes/ha was more effective than VGS plots in reducing runoff than soil loss. Whereas mean runoff for VGM, VGS and OMF plots were 28.67, 38.44 and 42.44 mm, respectively, the corresponding mean soil losses at 6 tonnes/ha were 980.5 kg/ha, 389 kg/ha and 1251 kg/ha, respectively. Mean soil losses were 629 kg/ha and 591.5 kg/ha higher on VGM than VGS plots at 4 tonnes/ha and 6 tonnes/ha, respectively. Mean No₃-N levels of runoff water on the VGS plots were 40.4% and 65.6% of the levels of the OMF and the control plots, respectively over 2003 and 2004. Nutrient loads of eroded sediments were highest for OMF plots and least for VGS plots. Carbon, Nitrogen and P contents of eroded sediments were 22–23.5%, 12–35.9%, and 20.6–37.6% lower on VGS plots than other treatments.

The significant beneficial effect of OMF in producing the highest yields was dwarfed by the potential danger of water pollution by nutrient loads in the absence of a soil erosion control measure. Although the differences were not significant, grain yields on VGM plots were 4% and 47.4% higher than on VGS plots when 4 and 6 tonnes/ha of grass mulch were applied.     

Response of soil properties and yam yield to Chromolaena odorata (Asteraceae) and Tithonia diversifolia (Asteraceae) mulches

Plant materials differ in their chemical composition, rate of decomposition and suitability as mulch materials. Experiments were conducted during 2006–2007 and 2007–2008 cropping seasons for early yam cultivation at Owo in the forest–savanna transition zone of southwest Nigeria to study the effect of Chromolaena odorata and Tithonia diversifolia mulches applied at 0.0, 5.0, 7.5, 10.0 and 12.5 t ha^?1 on soil chemical properties, leaf nutrient composition, growth and tuber yield of white yam (Dioscorea rotundata Poir). Both C. odorata and T. diversifolia mulches reduced soil bulk density and temperature; increased concentrations of soil organic matter (SOM), total N, available P, exchangeable K, Ca and Mg, leaf N, P, K, Ca and Mg; enhanced growth and yield of yam compared with control. The values of SOM, total N and available P and leaf N and P concentrations increased with increasing mulch rate. C. odorata mulch and T. diversifolia mulch applied at 10.0 and 7.5 t ha^?1, respectively, was found to be suitable for yam production. T. diversifolia mulch compared with C. odorata mulch produced higher values of soil chemical properties, leaf nutrient concentrations, growth and yield of yam. T. diversifolia mulch produced 19% and 18% higher tuber yield compared with C. odorata mulch during 2006–2007 and 2007–2008 cropping seasons, respectively.     

耕作措施对土壤特性及作物产量的影响

通过夏玉米田间试验研究了不同耕作措施及秸秆覆盖对土壤特性、水分状况、作物产量及水分利用效率的影响。试验处理包括常规耕作、深松、秸秆覆盖、垄作、浅坑及免耕。结果表明,秸秆覆盖可显著提高土壤蓄水量、作物产量及水分利用效率。其保水增产效果在干旱年份更加明显。深松可有效打破犁底层降低其密度,可增加作物根深、根长及根重,提高作物产量和水分利用效率。免耕可提高夏玉米早期田间土壤含水率,保持相同产量。     

Sunflower ( Helianthus annuus L.) Seeding Rate Additions to Forage Oat-Legume Mixtures in Newfoundland

Lingonberry (Vaccinium vitis‐idaea L.) cvs “Sussi”; and “Sanna”; were cultivated on mineral soil with four different soil surface treatments (Sphagnum peat mulch, sand mulch, plastic mulch and herbicide 3‐syclohexyl‐5, 6‐trimethylenurasil (lenasil)). Amount of annual weeds, plant coverage and yield were observed over five years. Weeds were most abundant in the first two observation years. Sand mulch was the least efficient for the control of annual weeds for both cultivars, whereas lenasil was the most efficient for “Sussi”;, and peat mulch for “Sanna”;. The plant coverage increased steadily throughout the years in the “Sussi”; plots, especially in plots mulched with peat. The spreading of “Sanna”; was slower in all treatments. It was best in plots mulched with peat or sand. Overall, “Sanna”; was more productive, with the highest yield on sand mulch and the lowest on lenasil‐treated plots. “Sussi”;, instead, yielded best on lenasil plots and poorest on sand.     

Effect of annual applications of pelletized dolomitic lime on soil chemical properties and grass productivity

Lime in pelletized form is potentially more convenient for farmers than ground limestone, as it can be applied using conventional fertilizer‐spreading equipment. Pelletized lime is intended to maintain an optimum soil pH when applied annually at a rate of 350 kg lime/ha/yr. Interactions between lime and N fertilizer rate were examined by applying 0, 75, 150, 225 and 300 kg N/ha/yr (as calcium ammonium nitrate) in combination with 0, 175, 350 and 525 kg pelletized dolomitic lime/ha/yr over 3 yr to a permanent grassland sward used for silage production in County Down, Northern Ireland. Equal rates of ground lime, from the same source as the pelletized lime, were applied as a comparison. Effects on soil chemical properties, grass dry matter (DM) yield and herbage nutrient removal were examined. Lime maintained or slightly increased the soil pH, particularly in the top 2.5 cm of the profile, but there was no difference in the performance of pelletized lime compared to ground lime in any of the parameters measured. Lime had no significant effect on grass DM yield or grass quality; however, there was a significant (P < 0.05) reduction in yield at the first cut, particularly in year 2, when the highest lime rate (525 kg lime/ha/yr) was applied in the absence of N fertilizer. The dolomitic nature of the lime (11% Mg) resulted in significant (P < 0.001) increases in soil and herbage magnesium levels, and this could be beneficial for reducing the incidence of grass tetany in grazing animals. The P content of the herbage was also significantly higher in plots receiving lime, which suggests that lime may have enhanced the mineralization of P or stimulated root growth.     

Influence of different mulch treatments on growth rate and activity of the earthworm Eudrilus eugeniae (Kinberg)

Growth characteristics of the earthworm Eudrilus eugeniae and the impac of its activity on soil properties were studied in soil culture. The highest growth rate, fecundity and total weight increase were recorded in cassava mulch, compared with cocoyam mulch, grass and plantain pseudo trunk mulch treatments. With animal manure treatments, growth rate was highest in poultry manure compared with cow and goat manures although total weight increases were highest in poultry and goat manures and lowest in cow manure. The worm activity expressed as percentage reduction of soil bulk density was greatest in cassava mulch followed by grass mulch, cocoyam mulch and plantain pseudo trunk mulch in that order. Various animal manures did not differ in this aspect. Total soil N and soil organic matter increased significantly in cassava and grass mulch treatmens while in plantain pseudo trunk mulch these factors decreased. Soil pH increased in cocoyam and plantain mulch treatments and decreased in cassava and grass mulch treatments.     

Tillage and mulch effects on productivity and water use of pea and soil carbon stocks

Soil management can notably influence crop production under rainfed farming; however, improper soil management is one of the key factors threatening sustainability. The objective of this 3 years’ study was to evaluate the performance of two types of tillage: conventional tillage (CT) and zero tillage (ZT) systems with four mulches; paddy straw mulch (PSM), maize stubble (MS), Imperata cylendrica (thatch grass, TG) and no mulch (NM) on yield and water use of pea (Pisum sativum) and physico-chemical properties of soil. CT and PSM have registered 11.1% and 36.1% higher pod yield, 10.0% and 40% improvement of water use efficiency (WUE) and 9.7% and 49.2% better harvest monetary benefit (HMB) over ZT and NM, respectively. Soil moisture content (SMC) was higher with ZT than CT. Placement of mulch has considerably higher SMC on upper soil layer over NM, but at deeper depth, there was no such evidence. The soil organic carbon (SOC) was considerably improved by 4.1% with ZT than CT, whereas, MS improved SOC by 1.9% than NM. The findings clearly suggested that CT along with PSM registered improvement in pod yield, WUE and HMB, but ZT and MS improved SOC at different soil depths and responded to carbon stock management.     

Influence of Polyethylene Mulch,Irrigation Regime,and Potassium Rates on Field Cucumber Yield and Related Traits

Cucumber (Cucumis sativus) was field grown from April 2001–July 2001 to determine the effects of mulch, irrigation regime, and potassium (K) rates on yield and related traits (i.e., leaf relative water content, water-use efficiency, and macronutrition). This was a factorial experiment with two irrigation levels (125% A pan daily versus 75% A pan every three days), two mulch levels (mulched versus unmulched), and three K₂O levels (20, 40, or 60 g/m²). Plants receiving reduced water application (75% A pan every 3 days) showed significant reductions in all parameters when compared with well-watered plants (125% A pan daily). The use of black polyethylene mulch (BPM) covers improved the plant dry matter, chlorophyll concentrations, fruit yield, and relative water content in leaves of well-watered plants and also improved K availability to the plants by keeping soil moisture higher than that of stressed plants without mulch. Using BPM increased plant water-use efficiency compared with that under the reduced water (RW) treatment. Reduced water application enhanced electrolyte leakage compared with that recorded under the well-watered (WW) treatment. Mulching decreased electrolyte leakage under the RW treatment. Increased K rates significantly enhanced leaf K in the mulched and WW plants. However, increased K rates did not increase leaf K in the RW plants. Reduced water application reduced leaf concentrations of all nutrients tested, i.e., nitrogen (N), phosphorus (P), K, calcium (Ca), and magnesium (Mg). However, mulching enhanced the concentrations of these elements, although their concentrations were still lower than those under the WW treatment. These results clearly indicate that field-grown number plants under mulched treatments were less stressed under semi-arid conditions and also that mulched treatments increased K availability to the plants.     

不同生育期淋洗对微咸水滴灌玉米农田水盐及产量的影响

为了明确不同淋洗时间对微咸水滴灌农田脱盐和增产的影响,在内蒙古河套灌区进步村节水综合试验站开展了微咸水滴灌试验,分别在拔节期(T1)、抽雄期(T2)、灌浆期(T3)设置1次畦灌淋洗,以及生育期无淋洗(CK)共4个处理,研究不同生育期淋洗对微咸水滴灌农田水盐及作物产量的影响。结果表明:不同生育期淋洗后0-60 cm平均土壤含水率提高了18.9%,且T1、T2和T3处理0-40 cm土壤含水率显著高于CK处理,持续时间分别为12,25,28天;生育期淋洗后土壤储水量和作物耗水量分别平均增加了20.92%和21.52%。生育期淋洗后膜内平均盐分降低了78.0%,拔节期、抽雄期、灌浆期淋洗后盐分分别下降了0.20,0.36,0.44 mS/cm。淋洗后膜内0-60 cm脱盐率平均提高55.01%,60-100 cm脱盐率平均提高125.79%,且淋洗后膜外脱盐率高于膜内,平均高38.90%。拔节期淋洗显著提高产量及其构成因子,产量提高了18.8%,穗长、穗宽和行粒数分别提高6.8%,5.5%,7.0%,收获指数提高了7.8%(P<0.05);抽雄期淋洗产量提高了8.1%(P<0.05),而灌浆期淋洗对产量无显著影响(P>0.05),故在拔节期淋洗土壤作物受盐分胁迫时间较短,增产效应最明显。     

Effects of mulch location on banana weevil,soil and plant nutrients,soil water and biomass in banana fields

Major constraints to banana (Musa spp., genome group AAA) production, a dietary staple for over 70 million people in sub-Saharan Africa, are pest infestations, poor nutrition and inadequate water. Although mulch can improve soil water and nutrient status, many farmers believe it also promotes the proliferation of banana weevil (Cosmopolites sordidus), one of the most serious banana pests. In this study, we evaluated the effects of mulch location (mulch to base of banana pseudostem; mulch recessed 1 m from the pseudostem) on banana weevil, soil and plant nutrient status, soil water, and banana growth and development. After 3 years, the fully mulched plots had significantly more soil Ca and Mg than plots that did not receive mulch. Banana foliar K concentration was significantly higher in both mulch treatments (full and recessed) than in the control (no mulch) plots. The mulched plots had greater recharge after rainfall events and higher soil water contents during dry periods due to increased infiltration in the mulched plots. However, the mulched plots also exhibited significantly higher banana weevil densities and greater plant damage than the control plots. There was no difference in weevil damage with mulch location, although weevil density was higher in the fully mulched plots throughout most of the trial. Despite greater weevil damage, the treatments that were mulched yielded significantly heavier bunches. Hence the effects of the mulch on soil water infiltration and banana foliar nutrient status outweighed the detrimental effects of banana weevil damage.