播期及生长调节剂对间作大豆倒伏和产量的影响

以大豆、玉米带状复合种植模式为基础,大豆选用耐荫抗倒伏品种‘渝豆11’,玉米选用半紧凑品种‘成单30’,试验采用两因素裂区设计,主区为播期(A),A1为大豆、玉米同期播种,A2为大豆较玉米晚播14 d,副区为9种不同种类及浓度的植物生长调节剂(B),分别于2022年春季和2023年春季在西南大学歇马科研基地进行试验.研究在大豆、玉米带状间作模式下不同播期及生长调节剂对间作大豆产量及其构成因素、根系形态特征和倒伏及茎秆形态特征的影响,研究结果如下:(1)播期及植物生长调节剂对间作大豆产量及其构成因素具有显著影响.播期上同期播种大豆产量高于晚播大豆(A1>A2),其中A1B5、A1B8处理优于其他处理,其两年平均产量较对照分别增长48.56%、40.92%.A1B5处理的单株粒数、单株粒质量、百粒质量最大,较对照两年平均分别提高33.96%、48.56%、10.93%.(2)播期及植物生长调节剂对间作大豆倒伏及相关指标具有显著影响.晚播大豆平均倒伏率较同期播种大豆增加了20.84%,抗折力、茎粗显著减少,株高、主茎节数显著增加,而节间长在两播期间无显著差异.(3)播期及植物生长调节剂影响间作大豆根系形态特征.在不同生育期,大豆总根长、根尖数总体上同期播种大豆优于晚播.在不同时期,整体上大豆总根长为S3307>DTA-6>6-BA,而大豆根尖数为DTA-6>S3307>6-BA.综上所述,在大豆、玉米带状间作模式下,在初花期喷施DTA-6的产量优于S3307和6-BA,同期播种喷施60 mg/L DTA-6产量最高,其次是50 mg/L S3307,但是S3307处理下的大豆倒伏率较DTA-6更低,且产量与DTA-6差异不显著,更适宜机械化收割,利于应用推广.

Analysis on Waxy Corn/Soybean Intercropping Pattern and Economic Benefit

The research mainly analyzed effects of waxy corn/soybean intercropping on yields of the two crops, as well as agronomic characters, and the economic benefits of the mode. The results showed that although yields of waxy corn and soybean went down by 21.19% and 31.04% per unit area, land equivalent ratio（1.48） kept higher than 1, suggesting the intercropping improves land use rate. Besides, due to the practice of intercropping, many characters of waxy corn grew, but of soybean declined. The economic benefits from high to low were waxy corn/soybean intercropping, monoculture of waxy corn, and monoculture of soybean.

Effects of Intercropping Patterns on Dry Matter Accumulation and Transportation of Maize(Zea mays L.) and Soybean[Glycine max(L.) Merrill]

[Objective] The aim was to discuss the group dry matter accumulation and economic benefits under the patterns of intercropping maize （Zea mays L.） with soy-bean [Glycine max （L.） Merril ]. [Methods] Zhengdan-958 and Luhuang-1 were used as the testing breeds to study the effects of intercropping patterns on dry matter accumulation and transportation of maize and soybean in Huang-huai-hai. [Results] For maize, the dry matter accumulation amounts per hectare of intercropping was significant higher than that of the monoculture patterns, especial y after silking, when it reached extremely level; while for soybean, the dry matter accumulation amounts before flowering and after flowering of monocropping were al significantly higher than that of the intercropping patterns. For both maize and soybean, the transfer amounts of monocropping were al significantly or extremely significantly higher than that of intercropping; and the transfer ratio of maize intercropping was 0.59% higher than that of maize monocropping, while for soybean, it was 4.74% higher. Fitted dry matter accumulation with Logistic equation, it showed that the difference in maximum dry matter accumulation rate between maize monocropping and intercropping reached significant level, while for soybean, the maximum dry matter accumulation rate and its appearance time as wel as duration time between intercropping and monocropping were al reached significant level. The total land equivalent ratio of intercropping was 1.30. From yield and output value, the total yield of intercropping were 10.97 t/hm2, 0.64% and 326.85% higher than monocropping of maize and soy-bean, respectively. The total output value of intercropping was 25 796.23 yuan/hm2, respectively 12.67% and 104.68% higher than of maize and soybean monocropping. [Conclusion] The study lays a basis for improving grain yield and economic benefits.

The Effectiveness of Coccinellids as Natural Enemies of Aphids in Maize, Beans and Cowpeas Intercrop

A field study was conducted in Busia district of Kenya to elucidate the dynamics of ladybirds in mixed stands of maize, beans and cowpeas to determine their efficacy as sole control measures for Aphids. Maize, beans and cowpeas were intercropped using conventional husbandry practices and the general Coccinellid quantified as follows： Colonies of four Coccinellids, starved for 12 hours to enhance feeding on Aphids were assessed. The effects of weather on the abundance of Coccinellids were also investigated and involved collection of meteorological data from the Busia District Agricultural Office （BDAO） and from Busia Farmers Training Centre （BFTC） and relating them to the abundance and predation values. The predator population was most abundant in the mixed stands of maize and beans （2.33 predators/30 Aphids） as compared to their occurrence in pure stands of cowpeas （0.85 predators/30 Aphids）. The genus Cheilomenes spp. was the most ubiquitous predator with a mean of 4.00 individuals/30 Aphids while Hippodamia variegata was the least abundant predator species with a mean of 0.92 individuals/30 Aphids in all the agro-ecosystems. The larvae of Hippodamia variegata were the most bio-efficient, consuming 32.44 Aphids while their adults were the least bio-efficient, consuming 4.22 individuals for a period of 12 hours. The Coccinellids consumed more Aphids at higher aphid densities （24.05 Aphids） than at lower aphid densities （9.44 Aphids） over the same period of time. Rainfall and relative humidity had significant （F = 3.675; P 〈 0.05） effects on the abundance of Coccinellids. Temperature had significant （F = 3.58; P 〈 0.05） effect on the abundance of Coccinellids though at a lower level. Rainfall （r = -0.162） and relative humidity （r = - 0.084） were both inversely correlated with the abundance of Coccinellids. On the other hand, temperature was positively correlated （r = 0.159） with the prevalence of Coccinellids indicating that warmer and drier conditions favoured their multiplication.